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QUERIES AND RESPONSES Archive- Page 3 Click for: Recent Q & A Page,
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Query (Asked by Saji from Calicut)Please tell me the dosage of buprenorphine for PCA. |
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Response by Dr. Mary Korula (Posted on 14th December, 2006) The PCA dose of buprenorphine is 0.03-0.1mg as bolus dose with a lockout interval of 8-20minutes. It causes lot of sedation, vomiting and nausea, hence people have added naloxone and droperidol to the infusion. Background infusions are not generally recommended with this. It seems to compare well with PCA morphine with a potency ratio of 24:1. Most of the studies are from Taiwan and China.(Reference-6th edition Miller 's Anesthesia) |
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Query (Asked by Atul Vyas from Jabalpur) What is submental intubation & when it is required? |
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Response by Dr. Anjan Trikha (Posted on 12th December, 2006) Sub mental intubation is a technique that is used in patients with pan facial fractures requiring corrective surgery where nasal intubation is not possible and oral intubation too has to be avoided. The ETT tube is placed as routine with a laryngoscope and its proximal end is brought out sub mentally through an incision at the floor of the mouth. We are routinely doing it patients with pan facial fractures posted for maxillo facial corrective surgery. |
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Query (Asked by Nidha ) During lap surgery, CO2 insufflation causes rise in BP even without hypercarbia, due to catecholamine release. Do we need to control it, particularly since the use of inhalationals to control BP increase risk of arrhythmias due to sensitization of myocardium by catecholamines and CO2 |
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Response by Dr. Mary Korula (Posted on 12th December, 2006) During lap surgery, the carbon dioxide and BP often increase. Concentration of Inhalational agents may have to be increased, so also additional analgesics may be required. The ventilation will have to be increased also, mainly by increasing the rate of ventilation so that the CO2 is brought back to normal levels. I presume you are worried that the hypercarbia and the increased concentration of drugs like halothane can sensitize the myocardium, precipitating arrhythmias. This is usually not so difficult to treat once the CO2 levels are brought under control with a little hyperventilation. Using pressure controlled mode instead of volume controlled mode may also prevent the use of high tidal volumes. Bradycardias are common due to visceral vagal effects which respond to anticholinergics and again this is more common when adequate analgesics are not administered to obtund these vagal effects. Isoflurane and sevoflurane cause lesser myocardial sensitization, avoiding nitrous oxide helps prevent increase in abdominal pressure and the systemic effects. |
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Query (Asked by Seshadri from Delhi) What is the difference between a "servo" ventilator and a "pneumatic oxygen powered" ventilator. Does a oxygen powered ventilator has limitations? |
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Response by Dr. J Divatia (Posted on 11th December, 2006) A servo mechanism is technically one in which an intervention is made in an attempt to reach a target, the effect on the target parameter is measured and a correction is made in the intervention delivered subsequently in order to meet the given target. It is in effect, a feedback loop. However the early microprocessor ventilators were called servo ventilators as a trademark of the Siemen's company. Today the company is taken over by Maquet, and they make a range Servo ventilators. However most sophisticated ICU ventilators today are microprocessor controlled and use servo or feedback mechanisms in their functioning. They are usually powered by electricity and gas in used only to deliver the required oxygen / air mixture and flow rate. A pneumatically powered ventilator runs on the driving pressure of air or oxygen, and that is essential to drive the various parts in the ventilator circuit. Most often such ventilators are simple transport ventilators. Some of these require electrical power but only for display of parameters on a screen. If electrical supply is shut off, the ventilator will still run, however monitoring and display functions may not. Pneumatic ventilators do not require electrical power but may deplete the gas cylinder more quickly. Electronic controlled ventilators allow more precise settings, but there is a chance of battery failure. When working with pneumatic circuits, one must be aware that some gas is used for operating circuits or valves , which is exhausted to the atmosphere and not delivered to the patient. Acceptable levels of gas internal gas consumption are < 5L/min. Thus a gas cylinder may empty faster than calculated from the delivered flow rate and capacity of the cylinder. |
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Query (Asked by Eyayalem Melese from Ethiopia) Please brief me the anaesthetic considerations for a patient with Myasthenia Gravis. Is regional anaesthesia recommended? |
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Response by Dr. Manimala Rao (Posted on 5th December, 2006) Myasthenia gravis is an auto immune disease with antibodies against ACH receptors The characteristic features of the disease are respiratory muscle weakness, ptosis, ineffective cough and decreased deglutition. The pre op evaluation should focus on the recent course of the disease, the muscle groups affected, drug therapy and any other co morbidities. Many of these patients present for thymectomy or concomitant unrelated surgical or obstetric procedures. Those with respiratory problems and difficulty in deglutition pose more problems for the anaesthesiologist. These should be aggressively treated and the condition to be optimized. A thorough pre op check is mandatory. The drugs and the dosages taken have to be listed systematically. These patients are usually on anti choline esterases and steroids and some times on other immuno suppressants .the anticholine esterases can reduce the levels of serum choline esterase levels. They are highly sensitive to non depolarizing relaxants. Steroids can reduce the immunity. Avoid sedative and narcotic pre medication. Build a good rapport with the patient and allay their anxiety. If general anaesthesia is a must these patients can be managed with out the use of relaxants. Propofol, sufentanyl and sevoflurane are the drugs of choice for induction and maintenance. If muscle relaxant is required then the choice is atracurium or precisely cis atracurium. Whenever a relaxant is used it is imperative one should monitor the block .In a retrospective review for thymectomy it has been shown that a combination of bupivacaine and sufentanyl epidurally for pain relief along with propofol and sevoflurane as the base anesthetic had less respiratory depression and better outcomes. (can j anesth48 446-451 2001).The combination was superior to the balanced anaesthesia with a relaxant. Epidural anaesthesia has been successfully used in obstetric patients requiring caesarian section. Medico legal aspects and controversies do exist in a neurological disease but graded epidurals seem to work well in obstetrics. The controversy regarding the stopping of anti choline esterase drugs is always present They are stopped only if there is high vagal dominance, or if there is worry regarding anastamosis disruption. They can also prolong the ester type of local anesthetics. A thorough pre op check with relevant investigations, optimizing drug therapy, choosing the correct anesthetic technique, combination better than balanced technique, regional alone as in obstetrics or orthopedic surgery and in severe cases ventilating electively would bring down the anesthetic morbidity |
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Query (Asked by Nidha ) Some RA enthusiasts are promoting cervical epidural as a primary anaesthetic of choice for thyroidectomies and all kinds of neck surgery. What is the expert's opinion on this trend? |
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Response by Dr. Anjan Trikha (Posted on 3rd December, 2006) Yes cervical epidural can be administered for neck surgeries. The best part about anesthesia is that surgeries can be carried out under different techniques by different anesthetists and each one of the anesthesiologist can defend his technique - primarily because of his expertise and the facilities available. I have seen video films for a series of cervical epidural for neck surgeries in a couple of conferences. All the presenters reported excellent results and no morbidities!!!!!!!!. The advantages quoted were primarily cost and standard advantages of epidurals over GA and quick discharge. I personally have nothing against the technique and as long as patient's choice and safety is taken into consideration the same can be used. My concern is whether the anesthesiologists advocating these would prefer to use them on themselves and next of their kin!!!! I personally have never given it and would never want it to be given to me if I ever need to under go a neck surgery. |
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Query (Asked by Saji from Calicut) While using circle absorber in paediatrics can we use the adult canister? |
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Response by Dr. Mary Korula (Posted on 1st December, 2006) In older children, an adult canister can be used with a smaller anaesthesia bag and pediatric corrugated tubing. Fresh gas flow is adjusted to 200ml/kg with a minimum of 3-4l/min. Once controlled ventilation is established, gas flows are decided with the help of endtidal PCO2.Compared to the resistance of ET tube , additional resistance of the canister is trivial . The ratio of the Childs tidal volume to total circuit volume is small, changes in the anaesthetic concentration can take some time to reach equilibrium unless higher gas flows are used. In young infants, adult systems should be used with caution because it does not provide adequate humidity especially when fresh CO2 absorbers are added to the circuit. Heat and moisture exchanging filters should be used. Adult circle systems may also add extra airway resistance to breathing ,especially when the inspiratory valve gets wet and sticky. So should not be used for spontaneous respiration. Circuit compliance may diminish the accuracy of measured tidal volume. If using uncuffed tubes and ventilators, use the pressure controlled mode to adjust for leaks rather than the volume mode! Special circle breathing systems for pediatrics with small canisters are available too but make sure the components fit into our standard machines. For further reading, Smiths Anaethesia for Infants and Children-7th edition- 2006. |
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Query (Asked by Sanjay Agrawal from Lucknow) Kindly tell me the perioperative fluid therapy in paediatric neurosurgical cases. What should be the right fluid for maintenance in such cases. What should be therapy in neonates? |
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Response by Dr. H. H. Dash (Posted on 28th November, 2006) In full term neonate one can use either normal saline or Ringer Lactate during Anaesthesia. The fluid calculation remains same as we calculate it for any other paediatric patient. If you are using normal saline one should monitor serum sodium level and also look for hyperchloremic acidosis. Along with the above parameters one must monitor the serum glucose level frequently so as to prevent hypoglycemia during surgery. In premature neonate one can use glucose along with half normal saline or Ringer Lactate. |
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Query (Asked by Rashmin from Abd) What type of anaesthesia should i give in a patient operate for caesarian section who had undergone surgery for brain tumor 2 months back? |
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Response by Dr. H. H. Dash (Posted on 28th November, 2006) The patient who had undergone Neurosurgery two months back one must assess and evaluate the following things: (1). Any residual tumor or pathological lesion left inside the cranial cavity. (2). Type of disability the patient is having after surgery. (3). What are the drugs the patient is taking after surgery. (4). Any other problems the patient is having. Once you have assessed the above points then you are anaesthetic technique for other surgery becomes easy. If the patient has got residual tumor one has to take care of intracranial pressure and cerebral blood flow. If the patient had got disability like monoplegia, hemiplegia or quadriplegia use of suxamethonium is deferred in such situation. And this patient usually requires good hydration. If the patient is receiving any antiepileptic treatment one should continue the morning dose of antiepileptic drugs. Last but not the least if the patient has any hormonal problem for which he/she is receiving hormonal therapy one should take care of the hormonal replacement. Finally, one has to take a decision about the anaesthetic technique after evaluating all the above points. |
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Query (Asked by Saroj Patnaik from Chennai ) How is third space loss calculated? Are there any guidelines for replacement of third space loss ? |
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Response by Dr. Mary Korula (Posted on 22nd November, 2006) The most significant internal fluid losses during surgery are cavitary losses and third space losses which constitute the non functional extracellular compartment formed by transport of fluids from the cells and extracellular space into a nonfunctional extracellular space. During major procedures , large amounts of fluids are sequestered into the third space from the functional extracellular space according to the degree of surgical trauma. In general, in mild surgical trauma, this is replaced as 2- 4ml/kg/hr,for moderate- 6ml/kg/hr.and for major abdominal surgeries, taken as 8-10ml/kg/hr. The exact quantity of sequestered fluid is difficult to ascertain, so these third space losses are just approximates. These infusion rates are estimates of initiating isotonic fluid replacement either normal saline or Ringers lactate. These rates will have to be adjusted to the patients response and length of surgery. This translocation continues into the post-operative period, hence the losses at start and end of surgery are not the same., It may have to be gradually reduced towards the end of surgery. It is wellworth remembering 'all preset formulations are only guidelines and not golden rules'. These fluids take about 3days for elimination from the body and if the renal function is compromised at any stage, this might constitute overload. One recent study showed upto 3L positive balance did not change ECV but above this can cause problems like increased demand on the heart, lungs, decreased tissue oxygenation and wound healing, coagulation problems, abdominal compartment syndrome etc. These guidelines may be more important in children where errors in fluid management are poorly tolerated. The type of fluids to be used is still a big debate- crystalloids vs colloids. high volume therapy vs restricted fluid therapy. The general consensus is start with crystalloids and then replace with crystalloid-colloids combinations. There are enough papers supporting both. Use of invasive monitoring - CVP, urine output all help. Again there are recent papers suggesting that going by traditional hourly urine output measurements as guides to fluid replacements may not be accurate and can lead to fluid overloading. So best is to choose a middle path remembering each fluid has has dose limits and disadvantages. |
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Query (Asked by Prabhaker from Vellore) A 30 year old man with spine instrumentation with pedicle screws and fixation 2 years back at levels T12-L1 has come for a below/knee amputation on the Right side. He has a paraperesis (Power of both lower limbs 3/5 with intact pressure and touch sensation). Can I give a spinal for him? |
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Response by Dr. Anjan Trikha (Posted on 20th November, 2006) A spinal block can be given to this patient - there is no contraindication. The issues involved are however important. The patient has spinal implants at T12 - L1 levels, and parapaeresis in both the lower limbs. There could be medico legal issues in the post op period in case the neural symptoms worsen after surgery and anesthesia. There could be a possibility of diificulty in positioning of the patient for the spinal and during surgery. I would personally go in for a GA. |
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Query (Asked by Hesham from Doha, Qatar) I would like to know how to calculate the cost of inhalation volatile anesthetics for each patient we operate upon. Is there any equation for that purpose providing that we know the FGF & the concentration used |
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Response by Dr. Manimala Rao (Posted on 19th November, 2006) This can be obtained by multiplying the dial concentration with fresh gas flow, FGF x dial concentration = the number of ml of vapour per minute. This has to be converted to ml of liquid which can be obtained by: Molecular weight (divide)/Density in Grams per ml x22,400 at room temperature. 22,400 is the volume of any gas at STP. The easiest is to ask the manufacturers and suppliers to provide the table regarding the cost. They work out the cost to different anesthetic agents and give you how much it costs at different settings. We get that from our Abbot dealers. You could try the same or use this formula to work out for the dial setting and fresh gas flow for vapour and convert the same to ml in liquid. If density is given in grams per/ dl then convert the same to ml. I do hope you will be able to calculate. |
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Query (Asked by Anand from Pune) What are causes of unilateral pulmonary oedema & treatment? |
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Response by Dr. Manimala Rao (Posted on 17th November, 2006) Unilateral pulmonary oedema usually occurs when any obstructive pathology is relieved. It could be mechanical, effusion, tumor or even pneumothorax. The obstruction could be laryngospasm which could lead to negative pulmonary oedema. This is usually bilateral but at times could be asymmetrical or rarely unilateral. The obstructive pathology when unilateral and relieved could end up in sudden unilateral oedema. the physiology is sudden release of obstruction and increased intrapleural pressures, coupled with hypoxia hypercarbia and acidosis can lead not only to increase in intra pleural pressures but also increase in hydrostatic pressure increase in capillary permeability. Blood may be redistributed to pulmonary circulation. This is more commonly observed in infants and children. Airway reactivity could be a triggering factor. The incidence is rare and some times could be dangerous. Early diagnosis and management with peep and mechanical ventilation or simple CPAP in less severe cases is beneficial. Use of nitric oxide in unilateral pulmonary edema has been tried in the management. Use of protease inhibitor for re expansion for bilateral pleural effusion has been tried. Quick diagnosis and ventilatory management is the most important aspect for good recovery |
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Query (Asked by Eyayalem Melese from Ethiopia) What anesthetics considerations should be taken for a patient undergoing abdominal iliac aneurysm? I need to know more about the long acting muscle relaxant. |
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Response by Dr. Mary Korula (Posted on 16th November, 2006) Regarding muscle relaxants for aorto-ileac aneurysms, I don't think it really matters what you use unless you have other concomitant medical disorders like IHD, hypertension etc when you want a controlled rate and blood pressure -you wouldn't want to use pancuronium then. If renal involvement, atracurium would be best. It also depends on whether you will be using sensory or motor evoked potentials for spinal cord monitoring. Motor evoked potentials are very sensitive to muscle relaxants, so you may have to taper the MR dose at the time of monitoring or use a Nerve stimulator. If you are using regionals like epidurals, the doses of MR can be drastically brought down. But local anaesthetics can interfere with evoked potentials too, so opioid based epidurals are far more suitable in these periods. |
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Query (Asked by Nidha) Neonates with full stomach undergoing RSI. Does the force applied during cricoid pressure need to be different to avoid damage to the delicate laryngeal structures |
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Response by Dr. Mary Korula (Posted on 16th November, 2006) I really don't know how much cricoid pressure must be applied to neonates for RSI. There is a lot of debate over this even regarding adult pressure for effectiveness. 40Newtons used to be the older teaching, its come down to 30N and now some say 20N is enough if applied correctly and adequately. There is one reference which says 100cms of water applied in infant cadavers was shown to be sufficient to prevent gastric regurgitation. But the main thing to remember is to be effective, it has to be done in the sniffing position and increasing pressure as the child goes into deeper planes of anaesthesia or esophageal ruptures have been reported. The thyroid cartilage and cricoid are closer in children, the cricoid more anterior and angled and many a time you actually block the laryngeal view if not done properly |
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Query (Asked by Balasubramaniaguhan from Karaikudi ) Is there any formula to adjust the dose of heavy Bupivacaine for spinal anaesthesia, based on height? |
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Response by Dr. Anjan Trikha (Posted on 14th November, 2006) No fixed dosage schedules have been mentioned as there are so many variables - height, baracity, speed of injection barbotage etc etc. The general rule that could be followed would be - Dose for hyperbaric bupivacaine in an adult is taken to be 1mg for 1.5 segment blockade of nerve roots. This dose does not take into consideration adjuvants that are added. Recent literature however has refuted any effect of height of the patient on the level of block achieved but has stressed on the dose, baricity and position of patient. This is under acceptable limits. |
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Query (Asked by Anand from Pune) Should we aim for tight glycemic control of blood sugar in a medial ICU? |
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Response by Dr. J. Divatia (Posted on 6th November, 2006) In surgical patients in the ICU, the trial by Van den Berghe showed that best results were obtained by maintaining blood sugar at 80-110, as compared to <200mg%. In a subsequent trial in medical ICU patients, the same authors found a subgroup of patients who stayed >4 days in ICU to have similar results. However attempting to control sugar to 80-110 may be difficult unless your ICU has excellent well trained nursing staff who can monitor BSL frequently and titrate the insulin infusion. Also, very tight control may lead to increased incidence of hypoglycemia; hence it is recommended in the Surviving Sepsis guidelines to maintain sugar levels less than 150mg% (80-150). It is advisable to maintain BSL < 150. A level of 180 or 200 is too high and should not be the target in medical or surgical ICU patients. |
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Query (Asked by Deepa from Pondicherry) What is the difference between the ventiltory modes - APRV and BIPAP? |
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Response by Dr. J. Divatia (Posted on 27th October, 2006) BIPAP (Drager) This is a pressure-controlled mode of ventilation. The clinician sets the Inspiratory Positive airway Pressure, PEEP and inspiratory time. The ventilator triggers the breath which is pressure controlled, time cycled and ends at the set PEEP. The difference between the 'old' pressure controlled ventilation and BIPAP in the Drager is that the expiratory valve in this ventilator is designed so that it opens just slightly during the inspiratory phase if the spontaneously breathing patient is exhaling at that time. This allows spontaneous breathing while maintaining the set inspiratory pressure. BIPAP functions as a pressure controlled SIMV mode. The set number of mandatory breaths are supported as pressure controlled breaths, additional spontaneous breaths are assisted by the pressure support level set. Airway Pressure Release Ventilation (APRV) can be looked on as a variation of BIPAP. The clinician sets the Pressure High and the Pressure low or release pressure and the time spent at each pressure. The pressure at the high level is extremely long, allowing a very short time for expiration to the lower pressure. It can be looked upon as an extreme inverse ratio BIPAP (8:1). APRV allows the patient to breath spontaneously during any phase of ventilators' mechanical cycle. |
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Query (Asked by Sanjit Roy from Kolkata) My brother has been diagnosed with MND. He has been in the hospital since September 9, 2006 and on ventilation ever since. Repeated attempts to wean him off the ventilator have proved unsuccessful. However, he needs ventilator support on an intermittent basis. In the present scenario, doctors have advised that to bring him home, he has to be put on home ventilator. Kindly advise us on the following: 1. What kind of a ventilator can be used at home? 2. What degree of medical supervision will be required? 3. What will be the cost of a home ventilator? 4. Any other medical equipment/infrastructure required at home? |
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Response by Dr. J Divatia (Posted on 27th October, 2006) Does your brother have a tracheostomy or is he receiving non-invasive ventilation by nasal / oral mask? If he has tracheostomy, you will need an invasive ventilator, but a simple one will do. It should have basic modes CMV, and pressure support. It should be electrically powered and not pneumatically driven. You will need good basic nursing care, suction apparatus and suction cathers. you will need either a reliable source of oxygen cylinders or an oxygen concentrator. Perhaps a pulse oximeter, more as a pulse monitor than as an oximeter, presuming his lungs are essentially normal. If he is on non-invasive ventilation, then he will need a non-invasive ventilator, with a facility for spontaneous and controlled (timed) ventilation. The cost can vary between 1.5 to 4 lakhs. Hope this helps. Good luck. |
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Query (Asked by J Edward Johnson from Nagercoil) A 45yrs male with COPD & IHD/old IW infarction & chronic AF, on digoxin & verapamil -was posted for Laparotomy for small bowel growth. Given CSE. With epidural catheter in situ bupivacaine 12.5mg with fentanyl 25mcg & epidural top up with 2% Xylocaine 2-4ml given. After 30mts pt developed severe hypotension. I tried to manage with IV fluids & IV phenylepherine 100mcg increment 2 doses. But pt developed severe bradycardia & hypotension- not improved I then used mephentamine. My question is why PE failed to increase BP & produced bradycardia. |
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Response by Dr. Yatin Mehta (Posted on 25th October, 2006) Phenylephrine is a pure alfa-agonist so it is known to produce bradycardia if the BP goes up which it did not. Also patients on both verapamil and digoxin can develop bradycardia which anyway patients with IWMI are more prone to develop. Patients with AF have lost their atrial kick so their cardiac output may be down by upto 30%. Patients with previous MI already have a reduced ejection fraction. so it not surprising that the patients had persistent decrease in BP after subarachnoid block. I would have given GA instead. |
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Query (Asked by Deepa Baskar from Pondicherry) A patient with hereditary spherocytosis presents with massive spleen for splenectomy. His platelet count is 70,000, with no symptoms. Which is the ideal time for platelet transfusion? |
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Response by Dr. Manimala Rao (Posted on 25th October, 2006) Hereditary spherocytosis is inherited anemia due to intrinsic defects in the spectin molecule which maintains the shape. The transfused platelets as well as patients own platelets are destroyed. They have such a short life that transfusion may be needed on a daily basis. The increased activity of the spleen leads to sequestration. The patient you referred does not have any symptoms as well as the count is 70,000. the best time is to give platelets after ligation of the hilum and also look for accessory spleen which can also destroy the cells. If the platelet counts are less than 30,000 some advise IVIG few days before so that the count can be above 30,000. It is safe to give transfusion at the time of induction and at the time of ligation of hilum. |
| Query (Asked by Saji KM from Maldives) I am working in an island nation and very often we have to shift patients by air to higher centres. Some needs respiratory support also. Using the ambu bag is a problem sometimes as patient is in a stretcher fixed on the floor and we are sitting in the seat with seat-belt fixed...My question is whether it is safe If I attach a tube of sufficient length between the one-way valve at patient-end and the bag using appropriate connectors. This would have prevented the risk of accidental extubation when the vehicle jerks very badly in bad weather. |
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by Dr. J. Divatia (Posted on 20th October, 2006) Good idea. There
should be no problem if you attach a long tube between the one-way valve
and the bag. The dead space is only from the patient upto the valve
anyway. You might just have to squeeze the bag a bit harder. |
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Query (Asked by Anand from Pune) Is it necessary to adjust dose of antibiotic in critically ill patient according to creatinine clearance even if patient is on daily hemodialysis? |
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Response by Dr. J. Divatia (Posted on 12th October, 2006) It is necessary to give the drug at the dose and interval recommended for the calculated or measured GFR. For most antibiotics an additional dose similar to the calculated dose needs to be given immediately after hemodialysis. For vancomycin, a single dose of 1gm lasts for 5-7 days even when the patient is being dialysed, as it is not dialysable. It is best to look up the manufacturer's recommendations for specific drugs and to refer to a reference manual. A useful website is www.uphs.upenn.edu/bugdrug/antibiotic_manual/renal.htm |
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Query (Asked by Arokia Arul from Nagercoil) 38yrs primi, PIH, asthmatic for elective LSCS. Epidural catheter placed at T11-12, 2% lidnocaine with epinephrine 7ml and 50mcg fentanyl given, postop analgesia 1%bupivacaine 7ml and 2.5mgm morphine (bolus) injected 4 hrs after surgery. Approximately 6hrs later she developed hypotension, tachycardia, sweating & itching of the face. What could be the reason? |
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Response by Dr. Anjan Trikha (Posted on 10th October, 2006) Surprising that for LSCS an epidural was inserted at T11- 12 ! There is no mention about the length the catheter inserted in the epidural space. The symptoms of hypotension. tachy, sweating and itching were all due to post op analgesic dose of bupivacaine and morphine. Itching could be due to initial fentanyl and later morphine in epidural space. The hypotension could be explained by the 7 ml of bupivacaine via the epidural catheter at T11 - 12. Most probably the patient would have been a 'bit dry' at the time the analgesic dose was given which caused the hypotension and the tachycardia. It is not uncommon for patients after LSCS under an epidural block to be fluid deficit if the same have been not replaced adequately taking into account the intra operative blood loss. Other things to be considered are the fact that the patient had PIH and asthma. Any of the drugs that she was taking for PIH if taken in the post op period with out proper fluid replacement could cause hypotension, tachycardia and sweating. |
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Query (Asked by Sumit Vasdev from Chandigarh) Is clonidine available in India for intrathecal use? |
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Response by Dr. Anjan Trikha (Posted on 6th October, 2006) No! It is not available in India for IV of Intrathecal use. |
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Query (Asked by K. T. George from Cochin) A 52 yr old male pt with frostbite, both legs and both palms gangrenous with acute renal failure, on dialysis, output 50ml/day. Surgeon wants to take up for amputation both legs and fingers. How can we proceed? |
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Response by Dr. Manimala Rao (Posted on 5th October, 2006) I would give minimum dose of ketamine anesthesia 0.3mg-0.5mg/kg Patient should be NBM at least 4-6hrs and use glyco for reducing the excess secretions which are not a great problem in this dosage. You can also supplement 25mics of fentanyl as adjuvant along with 1-2 mg of midazolam. keep all necessary airway equipment if need arises. |
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Query (Asked by Balasubramaniaguhan from Karaikudi) 22 yrs old female primi at 28 weeks of gestation presented with pain in the abdomen for past 24 hrs.USG Abdomen shows free fluid in the abdomen and a provisional diagnosis of appendicular perforation was made. What is the anaesthetic technique of choice and if spinal what should be the dose of bupivacaine? |
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Response by Dr. Anjan Trikha (Posted on 17th September, 2006) I think the technique I would follow is a GA rather than spinal. 28 weeks gestation is a bit of a concern but the incidence of going into labour for GA and spinal are nearly the same. A ruptured appendix is a provisional diagnosis could be any other thing too. In any case if spinal needs to be given one would need a block till about T6 at least so depending upon the height and keeping in mind that the patient is pregnant one would decide the dose. If spinal needs to be done - for what ever reasons - spinal bupivacaine 8 mg with 20 - 25 mics of fentanyl should suffice. Continuous epidural could be a better option. I would still insist on a GA. |
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Query (Asked by Nilegaonkar S from Pune) A 15 year old boy with cirrhosis, posted for splenectomy. INR 1.6 after three FFPs. Platelet count 29000. Surgeon requests epidural for post-op pain, and feels plat count need not worry as it will rise when splenic artery is tied. Is it wise to proceed with epidural and the surgery with this platelet count? |
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Response by Dr. Mary Korula (Posted on 7th September, 2006) 15 yr old with cirrhosis I would not give a regional for this child for the simple reason that he has liver disease and dysfunction where his bleeding parameters are deranged. The INR is corrected only after FFPS. Platelet count is still low, he has a dynamic thrombocytopenia. In ITP patients, with static thrombocytopenia and large spleens, the thrombocytopenia is due to sequestration in the spleen and usually the platelet count comes up dramatically after the splenic vein is ligated. Here the counts may not come up, bleeding parameters may be deranged till liver function comes back to normal. Besides there are so many other ways of rendering anesthesia and post-op analgesia for this child, why take a chance? A regional is not absolutely necessary here even if you take into account the risk -benefit ratios. I think there would be no way of justifying an epidural in this case if a neurological complication occurs. |
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Query (Asked by H. S. Saini from Ludhiana) Should there be accidental extravasation of relaxant due to misplaced IV cannula, what precautions should be taken? |
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Response by Dr. Mary Korula (Posted on 7th September, 2006) Most of the muscle relaxants are acidic in nature, atracurium having the lowest pH. There will not be much of a reaction with dermal tissues as alkaline drugs like thiopentone. The adequate plasma levels may not be achieved if it is for intubation and patient may be only partially paralyzed for surgery. Intermediate acting drugs may take longer time for elimination from muscle and tissues but shouldnt be a source of worry! Must be careful with longer acting drugs like pancuronium though, it may be wise to use a nerve stimulator to monitor residual paralysis after reversal and also go by clinical signs. Neostigmine if given I/V may have a shorter action compared to I/M or S/c pancuronium, recurarisation may be a possibility, monitoring of these patients till full recovery is mandatory. |
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Query (Asked by Satish from kurnool) A 3 year old child for emergency mandible fixation, weighing 10 kg, Hb-8gm%, failed nasal intubation & developed pulmonary oedema. What could be the reason? |
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Response by Dr. Manimala Rao (Posted on 31st August, 2006) The causes of pulmonary oedema during induction of anesthesia are mainly due to hypoxia, respiratory obstruction, overloading with fluids, anaphylactic reaction to drugs, anemia contributing to both anemic hypoxia as well as fluid overloading, and if the patient has inherent cardiac problem which was not evaluated properly. This child with 8 gms Hb is on the border line of anemia. Repeated intubations could lead to some obstruction in a child while holding the mask. You have not mentioned whether there was a drop in saturation. Even if it is to the level of 90% would harm the oxygenation in patients with borderline anemia in a three year old weighing 10 kilos. If there was any inadvertent increase in the fluid given at the time of induction, could also contribute. Evaluate again and you may be able to delineate the cause more effectively. |
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Query (Asked by DJ from Jaipur ) Are ropivacaine and levobupivaciane available in India. Where to get them from for thesis purpose? |
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Response by Dr. Anjan Trikha (Posted on 28th August, 2006) None of the two local anesthetics mentioned are available in India.In case you have friends abroad they could help you but the numbers required for a thesis could be a problem |
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Query (Asked by Saroj patnaik from Chennai ) 1.What should be the gap of time between two spinal analgesia procedures? 2.Can we repeat spinal analgesia intraoperatively for a prolonged surgery? |
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Response by Dr. Anjan Trikha (Posted on 22nd August, 2006) There are no standard recommendations regarding the gap between 2 SAB blocks. I am not aware of any studies that address this issue. Repeating a SAB between surgery should technically cause no problems though issues to be considered would be positioning and asepsis both at the LP site and the surgery site. Continuous spinal anesthesia has been used often with out any problems so a repeat block for continuation of the anesthesia should offer no problems as long as the dose of the LA and hemodynamics are taken care. Repeat SAB in an event of a failed SAB block is practiced by some, specially in cases of difficult airway and full stomach where conversion to GA could be a problem. |
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Query (Asked by Thomas Abraham from Abudhabi, UAE) A patient of road traffic accident, with multiple perforation of bowel, ruptured pancreas and spleen, hemo-pneumo-mediastinum & laceration on medial side of upper lobe of right lung. What precautions to be taken for anesthesia? |
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Response by Dr. Manimala Rao (Posted on 14th August, 2006) The case is a RTA with poly trauma. Every patient requires resuscitation and stabilization. In this particular case patient needs to have a chest drain, cvp line intubation and ventilation, a ryles tube insertion and may require vasopressors therapy after fluid and blood to keep up the pressure. This patient requires urgent surgery and may not have lot of time for resuscitation. With above mentioned measures patient has to be taken up for surgery with blood products and blood handy. These patients are likely candidates for DIC and later on for MOFS All have to be considered at the time of taking up for surgery. An informed consent is mandatory. The anesthetic technique is general anesthesia with highly titrating doses of induction and other drugs. If blood pressure is low one can give ketamine and rapid sequence intubation if he already not intubated. Since these patients are intubated at emergency room, one can give the additional doses of relaxant and fentanyl. Post operative elective ventilation is a must. These patients need at least 4-5 days of ICU care and pain relief and support of organ systems. |
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Query (Asked by Satish Lahure from Amravati ) Please specify from where could I get EMLA cream, (eutectic mixture of Local anesthetic Lignocaine and Prilocaine) Will you please give me address in India where it is freely available |
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Response by Dr. Anjan Trikha (Posted on 13th August, 2006) It is easily available in Delhi. The local product is known as Prilox cream and Neon makes it. |
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Query (Asked by Anand Tiwari from Pune) In patient on SIMV+PS ventilation if breath rate is kept as 10 on machine ie 6 second or respiratory cycle if I:E is 1:2 then which part of inspiratory cycle provides the SIMV supported breath and in which part patient takes his own breath. Does control mode breath and minute ventilation settings matter? |
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Response by Dr. J. Divatia (Posted on 2nd August, 2006) I presume that you are working with the Siemens (Maquet) Servo ventilator. In this ventilator, even when you select the SIMV mode, you must set the minute volume and the Control mode rate (Breaths per minute). This is because the tidal volume is calculated as MV divided by the set Control Mode rate. The Control Mode rate also determines the time for the ventilator breath. If it is set at 15, then 4 seconds are available for each ventilator breath, if is set at 10, 6 seconds are available, and so on. This includes inspiration plus expiration. Also select the inspiratory time and the pause time. The TV, inspiratory time and pause time will determine the pattern of the mandatory breath. The SIMV rate is however set separately. Thus to set SIMV, select SIMV (plus pressure support), and set the SIMV rate. Note that the SIMV rate should never be more than the Control Mode respiratory rate. In the SIMV mode, only the set number of SIMV breaths (e.g. 10, in this case) will be preset breaths delivered by the ventilator. All other breaths will be spontaneous patient breaths which are pressure supported. The question is how and when will the ventilator breaths be delivered and synchronized with the patient’s inspiratory effort. In order to understand triggering of mandatory breaths and duration of spontaneous (or pressure supported breaths) on the Servo, we need to understand the SIMV Cycle, which is made up of the SIMV period and Spontaneous Period. If the SIMV rate is set to 10/min, the SIMV Cycle is defined as 60/SIMV rate or 6 seconds. If the Breaths per minute (set Control Mode rate) is 15, then the SIMV period is defined as 60/Breaths per minute or 4 seconds. If IE ratio is 1:2, then I is 1.33 seconds and E is 2.66 seconds. The spontaneous period is defined as the difference between SIMV cycle (6 seconds) and SIMV period (4 seconds) = 2 seconds. If you draw a line of 6 cm, with each cm representing 1 second, then the entire line represents a SIMV cycle. The first 4 cm represent the SIMV period, and the last 2 cm represent the spontaneous period. A patient effort during the SIMV period triggers a machine breath with the preset values. This can happen once for every SIMV cycle. A patient trigger during the spontaneous period allows spontaneous (or pressure supported) breaths through the ventilator. A patient breath during the spontaneous period cannot trigger a ventilator breath. Thus if the patient is not breathing at all only the preset machine (mandatory) breaths will be delivered (10 per minute, once every 6 seconds). When the patient starts to breathe he will get the Pressure Support in the spontaneous period (2 seconds), and if he triggers in the SIMV period (4 seconds) the set mandatory breath will be delivered. In the next SIMV period the ventilator will wait for the patient to trigger but if the patient has not triggered within the first 90% of the SIMV period a mandatory breath will be delivered. Thus the Control Mode rate (Breaths per minute) is important not only to calculate the tidal volume, but along with the set SIMV rate, it determines the time available for the ventilator delivered breath and the time available for spontaneous breathing. |
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Query (Asked by Umesh from Chennai) What do the terms 'response time' and 'averaging time' mean in pulse oximetry? |
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Response by Dr. Mary Korula (Posted on 25th July, 2006) The pulse rate determination is not the same as the SaO2 determination in pulse oximeters. SaO2 and pulse rate calculations are based on independent time intervals. The pulse rate update is based on the previous 5 or 2 second interval. During each interval , the oximeter measures the time between the plethysmographic waveform peaks to calculate the pulse rate. Normally microprocessors calculate the SpO2 at 50 or 60Hz/sec. These calculations are averaged to determine the displayed SpO2. The displayed average is based on specific time periods and updated at specific intervals that depend on the selected response mode. This method of averaging provides a stable reading with low sensitivity to interference while retaining the ability to respond quickly to saturation changes because it allows erroneous SpO2 values like from probe movement and electrosurgery to be discarded. The Response mode indicates the SaO2 and pulse rate averaging time referred to as S or N or F modes (Slow, Normal or Fast). Ref: Ohmeda Oximeter Operation manual |
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Query (Asked by T Alcantara from Quezon city, Philippines) A diagnosed case of Breast CA Stage 3 s/p modified radical mastectomy, on 3rd cycle of chemotx who came in due to uterine bleeding secondary to incomplete abortion (retained placental tissue). Patient was in resp distress & could not tolerate lying down, decreased breath sound on left with wheezes & rhonchi on right. CXR: patchy density on R hilum (? pneumonic process, pulm congestion). They were entertaining sepsis in the immunocompromised. pt was asked for emergency D & C. My advise was to do a low spinal and if possible do the procedure with patient sitting & if she can tolerate D & C in a semirecombent position. However, pt insisted on being put to sleep so she was intubated & put to sleep. How will you approach management of this patient? |
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Response by Dr. Anjan Trikha (Posted on 22nd July, 2006) The decision to administer a general anesthetic was correct in such a case. There is no role for any neuraxial block in a scenario of a patient with bleeding P/V in respiratory distress with inability to lie supine and with a suspected diagnosis of impending sepsis. The past history of radical mastectomy on chemo would have no bearing on this decision to administer a general anesthetic. Spinal - low or otherwise is a relative contraindication in such cases. |
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Query (Asked by Sudhakar from Madurai) 26yrs female presented with bleeding PV, diagnosed as ruptured ectopic. Preoperatively pt was haemodynamically stable but her heamoglobin was 4.5gm/dl. Which is the ideal method of anaesthesia for this patient? why? |
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Response by Dr. Anjan Trikha (Posted on 19th July, 2006) There are no two views about the fact that the patient should receive a general anesthetic. A ruptured ectopic with anemia and emergency surgery would surely warrant a GA as hemodynamics & oxygenation can be better controlled with a GA than a neuraxial block in such a case. It is very unlikely that a patient with a Hb of 4.5 would have stable hemodynamics. She should be pale, tachycardiac and have a border line systolic BP. Rapid sequence induction after setting up of invasive monitoring and adequate fluid resuscitation is the technique of choice. There may be need for post op ventilation too so extubation may be delayed and carried out after HCt has been brought to near normal level. Spinal and epidural would offer no benefit to such a patient. Continuous epidural may have the benefit of better post op pain control but pain can be adequately managed by other modalities too. Invasive monitoring if needed is better tolerated under a GA than a neuraxial block. |
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Query (Asked by Selvakumar from Coimbatore) 32/f posted for LMCA aneurysm clipping. Had two normal deliveries, last 6years back. Pregnancy associated hypertension on both occasion. No untoward complications. No other major medical history. All routine blood investigations normal, except for reversal of A/G ratio. Pt's GCS 15/15. induced with propofol and fentanyl relaxed with atracurium. Intubated. & maintained on atracurium infusion, isoflurane0.4% to 0.8% and nitro patch. Monitored with ECG V5,SpO2, EtCO2. NIBP, CVP and hourly urine output. almost two hrs went on well with this routine technique. Just two minutes after applying temporary clipping, first I noticed a fall in SpO2 from 100 to 85, NIBP showed 50 systolic, EtCO2 showed 10mmHg, CVP 20cm, no radial & femoral pulse felt.. I informed the surgeon, He told there is no major bleeding near aneurysm. I used dobutamine and within in a minute it responded. What is the reason for sudden lowering of BP? Post op Pt is doing good without any neurological deficit. |
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Response by Dr. H. H. Dash (Posted on 18th July, 2006) Fall in blood pressure along with simultaneous decrease in EtCO2 upto10mm Hg and Spo2 85% and CVP increasing to 20cm H2O suggest that there was massive venous air embolism. How and why it happened after temporary clipping is very difficult to explain. The other cause could be due to stunned myocardium as the patient is a known hypertensive for long time. To diagnose this ECG changes are paramount. But I strongly feel stunned myocardium is unlikely in this case. As regards, the management is concerned I must congratulate for managing your patient very well. |
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Query (Asked by Bhaskar Dutta from Dibrugarh ) Which preoperative investigations are mandatory (for an anaesthetist) for a 35yr old pregnant lady coming for elective LSCS, who is a diagnosed case of SLE for the last 8 yrs? What is the anaesthetic technique of choice in this patient? |
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Response by Dr. Manimala Rao (Posted on 18th July, 2006) SLE is an auto immune chronic disease with multi system involvement, mainly affecting women of child bearing age. Antibodies and immune complexes play a pivotal role .Pre op assessment should include thorough examination of all systems as there is multi organ involvement. It should also aim at maternal and fetal risk as well as consider the drug usage and dosage as well as anesthetic management. The clinical signs which can affect the anesthetic management are aseptic meningitis, high blood pressure, pericarditis, pneumonia, coagulation abnormalities and recurrent thromboembolism. Anemia and thrombopenia significantly alter coagulation and are a great concern .Pregnancy with overt disease has bad outcomes and renal flare up have worse outcomes. Review of literature shows that general anesthesia is given more number of times as compared regional as it is contraindicated by the presence of either neurological or hematological complications. Difficult intubation should also be kept in mind .The most frequent complications are hematological and cardiovascular followed by renal flares. 5-37% of patients have lupus anticoagulant factor It causes prolongation of coagulation lab parameters but at the same time can cause systemic intravascular thrombosis Use of antiplatelet drugs and anticoagulants make the regional technique unsafe and contraindicated. Renal flare-ups are common and one should use drugs which have least effect on the renal function. General anesthesia appears to be safer option and I would use G.A with out hesitation Investigations pertaining to these systems are mandatory. A graded epidural could be contemplated when there are no coagulation abnormalities, or the presence of LAF, anticardiolupin antibody. General anesthesia may be a safer bet in this particular patient. Constant monitoring titrating the drugs and understanding of the gravity of SLE and a team effort would reduce the complications. Use of thio and suxamethoneum for intubation midazolam and fentanyl in titrated doses after the delivery should not give rise to many problems. Atracurium could be the drug of choice for prolonging relaxation. Oxygen therapy and watch for any coagulation abnormality is mandatory. |
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Query (Asked by I J Rajesh from Madurai) I had an 18 year old head injured patient with GCS 3-4 posted for emergency craniotomy (for removal of SDH-already intubated & resuscitated in casualty) I induced with Thio 250mg, vecuronium 6mg & fentanyl 100 maintained with O2 N2O & isoflurane 0.6%, ventilated with 600ml Vt, F-16 I;E 1;2- few minutes after dural opening brain started to bulge drastically & we administered Mannitol (300ml), Frusemide 60mg, (Dexa 8mg preop by neurosurgeon) but unable to control brain bulge & had to close without bone. How to avoid this what other steps would have prevented this? |
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Response by Dr. H. H. Dash (Posted on 18th July, 2006) The acute brain bulge during removal of SDH is commonly encountered due to massive haematoma or may be due to counter coup injury in the other side of the brain which may gets aggravated following evacuation of SDH. In such situation it is the neurosurgeon who has to initiate prompt management. My sincere suggestion is in the face of acute brain bulge, that, you should have administered intravenous thiopentone drip. Thiopentone decreases both cerebral blood volume and cerebral oxygen consumption thereby offers brain protection. To avoid such problem in future one must analyze the CT Scan properly and must co-relate with the clinical finding. |
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Query (Asked by Sanjith from Pune) What is a guarded L.P and how is it performed? |
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Response by Dr. Anjan Trikha (Posted on 12th July, 2006) The term guarded spinal is not an anesthetic term. Spinal anaesthesia when given under extreme caution / under certain predetermined safe guards can be termed as guarded spinal. The term does not denote any special procedure but signifies extreme caution. Alternatively a spinal given under close supervision too can be termed as guarded spinal. |
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Query (Asked by Jiju T N from Kottayam) Anaesthetic implications of isolated dextrocardia? Preferred choice of Anaesthesia? |
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Response by Dr. Yatin Mehta (Posted on 12th July, 2006) 1. There is no real major anaesthetic implication of isolated dextrocardia except if you are monitoring ECG (specifically ST segment analysis) chest lead (V5) should be placed on right side not on left. 2. Right internal jugular cannulation and insertion of PAC may be difficult. 3. Regarding choice of anesthesia - there is no preferred choice of anaesthetic form dextrocardia point. The choice of anaesthetic should be dictated by patient's other considerations. Ref: Wayward Pulmonary artery catheter: Chand RK, Dhole S, Dholakia H, Mehta Y. JCTVA 20:3; page 456, 2006 |
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Query (Asked by Selvakumar from Coimbatore) What may be the reason for severe hypotension following renal transplant in the recipient? 30/m well conducted G.A. No intraopertive complication. urine was draining about 100ml every 15 minutes. after anastamosis. |
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Response by Dr. Mary Korula (Posted on 8th July, 2006) Usually hypotension occurs because of fluid imbalance. Its mandatory to replace the high urine output and maintain hydration from the beginning. This is especially so in children. Metabolic Acidosis can cause hypotension and if pre-op acidosis is not corrected by dialysis, that could be a reason. This is transient though and corrects after the transplant. Pre-op undetected septicemia can be worsened with immunosupression. This can be another cause of hypotension. Pericardial effusion and uremic pericarditis persisting after dialysis are other causes if renal function after transplant doesnt improve.Other medical causes would include cardiac and respiratory causes like an unexpected pneumothorax due to rupture of bullae. Recently, we had such a case. Anastomotic leaks and surgical causes should be ruled out. Aggressive control of pre-op blood pressure with 5-6 long-acting anti-hypertensives used to be a common cause for hypotension after transplant in earlier days, but this practice has been discontinued over the years. |
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Query (Asked by Anand from Chennai) What is Neurological and Adaptive Capacity Score? |
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Response by Dr. H. H. Dash (Posted on 6th July, 2006) "Neurological and Adaptive Capacity Score (NACS)" was described in 1982 by Anial Tison et al. It was developed to evaluate the neurobehaviour of term, healthy newborns ; specifically, to detect CNS depression from drugs administered to the mother during labour and delivery and to differentiate these effects from those associated with perinatal asphyxia and trauma at birth. NACS, using 20 criteria, evaluates five general areas (I), Adaptive Capacity (II), Passive tone (III), active tone, (IV) Primary Reflexes and (V) General neurologic status. Each criterion is given a score of 0, 1 & 2 0 = Absent or grossly abnormal 1 = Medicine or slightly abnormal 2 = or normal Max. Possible score is 40. (I). Adaptive Capacity (Five points) (II). Passive Tone (Four points) (III). Active Tone (Five points) (IV). Primary Reflexes (Three points) (V). General Assessment (Three points) The NACS is only available in below mentioned journals: Anesthesiology 1982 ; 56 : 340 - 50 Anesthesiology 2000. Jan ; 92 (1) 237- 46. |
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Query (Asked by Arokia Arul from Nagercoil) 42 yrs male, smoker posted for vericose vein stripping. Anesthesia induced with propofol, morphine LMA 4# maintained with N2O,O2&Halo. Bradycardia treated with atropine 0.6 given, developed hemodynamically significant atrial fibrillation. How to proceed? |
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Response by Dr. Yatin Mehta (Posted on 24th June, 2006) In a 42 year old patient the most likely cause of AF is post atropine along with halothane and probably a light plane of anaesthesia i.e. its probably benign and not secondary to CAD. Because it is haemodynamically significant and patient is already under G.A., I would cardiovert him. It is highly likely to convert to SR. If it does not, after a couple of shocks then either give amiodarone (300 mg in slow infusion) or a beta blocker like Esmolol or Metoprolol all of them will certainly reduce the rate and restore haemodynamic stability or even may revert to SR. In any case after reducing the rate with stable BP one should go ahead with the case but not with halothane! |
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Query (Asked by Rajan & Udita from Udaipur) Use of Oxygen vis a vis Air-Oxygen mixture during cardiac anaesthesia, their indications, advantages and disadvantages. |
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Response by Dr. Yatin Mehta (Posted on 9th June, 2006) Some centres use only oxygen while others use O2 + Air during cardiac anaesthesia. Although short term 100% O2 inhalation may not have any adverse effects, still why to use higher O2 than necessary? Many people use a mixture till CPB and use 100% O2 after coming off a) so that microbubbles get absorbed b) PaO2 is generally on the lower side immediately after coming off CPB so that would take care of it. c) If there is a protamine reaction at least PO2 is taken care of. Off pump CABG people generally use O2 + Air otherwise but many use 100% O2 during anastamosis as there is hypotension, arrhythmias, lung retraction or hypoventilation (deliberate to facilitate surgery) during this period. |
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Query (Asked by Rebecca Reeves from Nottingham, UK) What are the associated contra indications of using facial CPAP with an oesophageal tear? |
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Response by Dr. J. Divatia (Posted on 7th June, 2006) Non-invasive CPAP or noninvasive positive pressure ventilation can allow air to enter the pharynx and GI tract. Insufflation of the esophagus and stomach can occur to a greater extent if the airway is obstructed, or the patient has respiratory distress with aerophagy. In patients with an existing esophageal tear, exposing the esophagus to higher pressures and flow associated with CPAP or NIPPV could possibly cause the tear to extend. It can also allow air to track into the mediastinum. Both the above can cause mediastinitis which is a serious, often fatal complication of esophageal perforation. Thus NIPPV and CPAP should not be used in such patients, and tracheal intubation should be preferred. NIPPV should also probably not be applied to treat respiratory failure after upper GI surgery. Again, the anastomoses may be subjected to greater stress with and may result in anastomotic dehiscence. A Case Report of Esophageal Perforation Associated With Noninvasive Ventilation has been reported. (Chest. 2002;122:1857-1858.) Thus I would not ordinarily recommend the use of noninvasive CPAP or NIV in patients with esophageal perforation. |
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Query (Asked by M.Kannan from Tirunelveli) Is there any lower age limit in using Propofol. Can it be safely used in new born and infant |
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Response by Dr. Mary Korula (Posted on 28th May, 2006) Propofol had been discouraged in very small infants and neonates due to lack of studies regarding its safety in this age group. However it is still being used all over the world for short procedures like MRI, diagnostic procedures and for treating laryngospasms. It is discouraged because of the life threatening complications like bradycardia, apnea and hypotension especially in smaller kids. More and more case reports on Propofol Infusion Syndrome is the cause for withdrawal of long term infusions for sedation in ICU . This includes sudden bradycardia, complete heart blocks, hyperlipedemia, liver function abnormalities, metabolic acidosis, rhabdomyolysis and myoglobinuria. Acute pancreatitis has also been reported in kids after propofol. More studies are required to establish its safety. The safe dose and duration still remain unclear. Infants and smaller weight babies need 50-100% more dosage than older children to maintain plasma concentrations due to their increased volume of distribution. Why some kids are more susceptible is also unclear. Lack of substrate and cellular hypoxia , build-up and direct toxicity of fatty acids account for the clinical features, so one should be aware of this fact. Adequate carbohydrate delivery (6mg/kg/min) is recommended with infusions. Early identification might be possible by measurement of acyl –carnitines (not a bedside teat yet) and subclinical signs of B- oxidation. For short procedures, 1.5-2mg/kg is generally used and boluses of 0.5-1mg/kg as required for additional doses. But most of the studies have shown on an average , they require induction doses of atleast 4mg/kg (double that of adult dose) and this is also the minimum dose per hour recommended for short-term infusions. For treatment of laryngospasm and deepening anaesthesia , dose recommendations are 0.25-0.8mg/kg . |
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Query (Asked by Eyayalem Melese from Ethiopia) What anesthetics considerations should be taken for HIV patient who is on ART& undergoing surgery? |
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Response by Dr. Mary Korula (Posted on 28th May, 2006) Though the routine use of new antiretroviral therapies including protease inhibitors have caused decrease in the morbidity and mortality, significant drug interactions are now being reported especially with the highly active HAART therapy. There are so many ART drugs available now and all have their unique side effects. Of importance are the protease inhibitors, with wide ranging side effects like Glucose intolerance, Hyperlipedemia, abnormal fat distribution, high aminotransferase concentrations and Hepatitis. The most important concern may be inhibition of cytochrome P-450 which is required for metabolism of many drugs. Ritonovir, one of the popular ART drug, is a one of them and has been shown to inhibit metabolism of Fentanyl and reduce its clearance by 67%.So chances of respiratory depression with the usual doses are quite high. The same applies to benzodiazepines and opiates. Careful titration is mandatory while using these drugs. It can boost the actions of other protease inhibitors also. These patients may be on other drugs for tuberculosis, toxoplasmosis , mycobacterium, fungal infections etc. We still don’t have enough database for definite conclusions. For updates, look up http//HIVinsite.ucsf.edu. Especially look for peripheral neuropathy, renal toxicity, pancreatitis, bone marrow depression, lactic acidosis, respiratory problems Anaesthetic drugs should be used with caution as in all these conditions elsewhere. So a good pre-op assessment and drug history is mandatory. Intensive investigations including blood count, clotting functions, pulmonary, liver and renal tests to choose the best relaxants. Remember HIV is a multi-organ disease, affecting cardiac, pulmonary, hematological, gastro-intestinal and neurological problems. Cardiac considerations including coronary arteriosclerosis, drug interactions with antihypertensives, anti-arrhythmic, digoxin, warfarin, and other cardiac drugs should be kept in mind. Pulmonary status may be more important .Respiratory problems may make regional anaesthesia a good option wherever possible. |
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Query (Asked by Chetan from Nagpur) Can you please guide me about the optimal concentration of bupiviaine and fentanyl for continuous thoracic epidural analgesia for thoracotomies as well as the infusion rate |
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Response by Dr. Anjan Trikha (Posted on 9th May, 2006) The most commonly used concentrations for thoracic epidural infusion for post op pain are - Bupivacaine 0.125% + 2 ug / ml of fentanyl. This solution is not available commercially but can be made by the hospital pharmacy for ensuring sterility or can be made by the anesthesiologist himself. The volume to be infused varies between 5 - 15 ml / hour. The volume needs to be adjusted according the the dermatomes involved and the response of the infusion. Frequent checks for the loss of sensory sensations need to be done, and the rate adjusted. Alternatively Bupivacaine 0.125% and fentanyl 4 ug/ml can also be used. Personally I use the former solution first and if the patient is not pain free ( VAS = / < 3) both at rest and at movement I switch over to the second solution. I also often start the infusion just before the surgery has ended and continue the same in the post op. |
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Query (Asked by Tasalam from Karachi) I want to know that is there any hemodynamic stability by adding ketamine0.3 mg/kg with 0.5% bupivacaine 20 ml in epidural anaesthesia. |
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Response by Dr. Anjan Trikha (Posted on 9th May, 2006) The combination of bupivacaine and ketamine has been used epidurally for post op pain relief and also for decreasing the opioid requirement in the intra operative & pot op period. There have been reports of better hemodynamic stability and less use of vasopressors when ketamine - bupivacaine epidural solutions were used as compared to bupivacaine - fentanyl or bupivacaine alone solutions. In these reports the hemodynamic parameters were monitored as part of the studies done primarily to evaluate the opioid sparing effects and / or better quality of analgesia of ketamine - bupivacaine solutions. I am not aware of any reports where ketamine - bupivacaine solutions were used PRIMARILY to achieve better hemodynamics. I have personally been involved in one of such studies where such solutions were used. We found no significant difference in hemodynamics when bupivacaine alone or bupivacaine - ketamine solution was used epidurally, though opioid requirements and time to first supplementary analgesia dose were significantly different between the two solutions. I am also not aware of any personal communications printed or otherwise where such a solution has been used out of choice for better hemodynamics. |
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Query (Asked by Sanjith from Pune) I am working in a neuro trauma unit which deals with a huge load of the above mentioned pts on a daily basis. I am regularly achieving the central venous access through the jugular route. I would like to know whether this route would hamper the venous drainage, if so, is there any evidence for the same? |
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Response by Dr. H. H. Dash (Posted on 8th May, 2006) We also do lot of internal jugular vein cannulation in our busy Neurosurgical operation theatre. If there occurs kinking of neck vessels due to position then you may land up in problem that is brain bulge otherwise no problems. Fixing of the cannula may come out during cleaning of head with antiseptic solutions prior to surgery. To avoid all these we carry out subclavian cannulation more frequently. |
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Query (Asked by Divesh from Delhi) Difference between Bilevel pap and Biphasic pap |
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Response by Dr. Manimala Rao (Posted on 29th April, 2006) Most call it as bi level pap as it is applied in inspiration as well as in expiration. Since two levels are used in the two phase of respiration it is often referred as bi pap bi level pap or even biphasic pap. I did find anything separate for the biphasic pap. All the articles mention both names. Since the it is used in the two phases of respiration it is often referred as biphasic |
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Query (Asked by Magdy Farid from KSA ) Post operative pneumothorax ,causes and management |
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Response by Dr. Manimala Rao (Posted on 29th April, 2006) Your question is a very long one to answer. The post operative causes are very much related to the type of surgical procedures. The cardiac and lung surgeries are more likely to develop pneumothorax. As for anesthesia is concerned one should look at the pre op causes. Patients who are having COPD are more likely to develop it during surgery or in the post op period. respiratory Obstruction due to any cause can lead to high pressures and lead to barotrauma. Severe bronchospasm leading to use of high pressures could lead to the same. Subclavian vein cannulation can give rise to the same. Pneumomediastinum has been reported after tracheal injury during intubation. Endotracheal tube obstruction due to any reason be it a mucus plug or a herniated cuff can give rise to a pneumothorax. Bracheal plexus block can produce a pneumothorax. There are any no of causes and one has to have at least the common ones in mind, when we doing a procedure, using a technique or a particular surgery. Even nephrectomies can cause the same. What is most important is to understand the various etiological factors and look for the same and have a high degree of suspicion .It is important to diagnose the same and take necessary action which is life saving. Tachycardia oxygen desaturation, hypotension are a few warning signs. Absence of breath sounds and hyper resonant note on percussion can be of help. Xray chest will clinch the diagnosis. If it is a tension pneumothorax as an immediate measure one can insert a large bore iv canula in the second intercostal space in the mid clavicular line. IF the hemodynamics and oxygenation are alright then tube thoracostomy is the answer. It is humanly not possible to give all the etiological factors and one should keep in mind that it is a treatable condition and simple thocostomy inserted on the side of pneumothorax in the anterior-mid axillary line in the 6th intercostal space at the earliest is life saving |
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Query (Asked by A M Jagadeesh from Bangalore) What is the criteria for tidal volume in children. Sometimes 12-15 ml/kg also is not enough to control EtCO2 as well as PaCO2. Even though BMR & cardiac output are fairly comparable & within normal limits the TV requirements vary for children of same weight. |
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Response by Dr. Anjan Trikha (Posted on 26th April, 2006) There are so many variables when we are ensuring normocapnia. Some of the variables that effect are - TV, RR ( i.e. Minute ventilation), compliance of the ventilatory circuits etc, circuits been used, ventilatory device, dead space, and condition of lungs. In adults these variables also effect the ventilatory mechanics but they become much more significant in neonates and children. Thus there could be a difference in TV needed for maintaining normocapnia. |
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Query (Asked by S.Saravanan from Cuttack) What is the role of Inj. ACTH in the treatment of post dural puncture head ache? I am using last one year in the dose of 20 IU Intramuscularly for LSCS pt who suffer PDPH after spinal anaesthesia. It is working really well. But I don't know the mechanism? Please explain. |
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Response by Dr. Anjan Trikha (Posted on 26th April, 2006) ACTH has been used for treatment of PDPH. It is not a popular modality as better options that have been authenticated have been described. ACTH supposedly helps in PDPH by causing water retention. This is just an extension of the first line of treatment of PDPH i.e. good hydration. In ensuring good fluid intake one ensures a good volume of CSF formation that is ultimately leaking and causing low pressure headache after spinal tap. ACTH is supposed to add to this. I am unaware of any RCTs or prospective trials where the use of ACTH has been authenticated. |
