|Year : 2021 | Volume
| Issue : 1 | Page : 17-25
Effect of dexmedetomidine on hemodynamics and recovery profile in children undergoing laparoscopic Stephen–Fowler's Stage-2 orchidopexy under general anesthesia: A prospective randomized controlled study
AH Shruthi, G Anuradha, YR Chandrika
Department of Anesthesiology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
|Date of Submission||02-Jul-2020|
|Date of Decision||25-Sep-2020|
|Date of Acceptance||06-Oct-2020|
|Date of Web Publication||22-Feb-2021|
Dr. A H Shruthi
Department of Anesthesiology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Background: Stephen–Fowler's Stage-2 (SF-2) orchidopexy for high intra-abdominal testes poses the challenge of both laparoscopic and open urogenital surgery to the pediatric anesthesiologist. Balanced anesthesia supplemented with regional analgesia remains the standard technique adopted. Studies involving intravenous (IV) dexmedetomidine as an adjuvant anesthetic in children are sparse.
Aims and Objectives: The aim and objective was to study the effect of IV dexmedetomidine on intraoperative hemodynamic stability, airway reflexes, and hemodynamic responses to extubation and postoperative analgesia.
Materials and Methods: This prospective randomized controlled study was conducted on thirty children undergoing laparoscopic SF-2 repair to receive balanced anesthesia with isoflurane. Group D patients received IV dexmedetomidine 1 μg/kg bolus over 10 min after induction followed by an infusion at 0.5 μg/kg/h and Group C patients received regional analgesia. Hemodynamic parameters, sedation, agitation, pain scores, time to rescue analgesia, and time to discharge were documented.
Results: A significant change was discernible in the heart rate and systolic blood pressure with intraoperative hemodynamic stability in Group D patients, which was comparable to baseline values. Smoother extubation with better hemodynamic stability (P < 0.001) and decreased agitation (P < 0.05) were noted in Group D patients. Children in Group C were observed to have lower sedation scores postoperatively (P < 0.05). Time to rescue analgesia was statistically significantly prolonged in Group D (P < 0.001) without any change in time to discharge from hospital.
Conclusion: IV dexmedetomidine 1 μg/kg bolus followed by an infusion of 0.5 μg/kg/h gives better intraoperative hemodynamic stability with smoother extubation and prolonged postoperative analgesia without undue side effects in children undergoing SF-2 orchidopexy.
Keywords: Children, dexmedetomidine, general anesthesia, laparoscopic, Stephen–Fowler's Stage-2 orchidopexy
|How to cite this article:|
Shruthi A H, Anuradha G, Chandrika Y R. Effect of dexmedetomidine on hemodynamics and recovery profile in children undergoing laparoscopic Stephen–Fowler's Stage-2 orchidopexy under general anesthesia: A prospective randomized controlled study. Indian Anaesth Forum 2021;22:17-25
|How to cite this URL:|
Shruthi A H, Anuradha G, Chandrika Y R. Effect of dexmedetomidine on hemodynamics and recovery profile in children undergoing laparoscopic Stephen–Fowler's Stage-2 orchidopexy under general anesthesia: A prospective randomized controlled study. Indian Anaesth Forum [serial online] 2021 [cited 2021 May 9];22:17-25. Available from: http://www.theiaforum.org/text.asp?2021/22/1/17/309738
| Introduction|| |
Laparoscopy has been commonly used in both diagnostic and therapeutic treatment of undescended testes (UDT). For high intra-abdominal testis, two-staged Stephen–Fowler's (SF) orchidopexy is performed. Balanced anesthesia with multimodal analgesia is the standard technique adopted. Dexmedetomidine, a potent a2adrenergic receptor agonist, is a frequently used drug due to its excellent sedative, analgesic, and sympatholytic properties without causing respiratory depression., Because of the above actions, it is known to reduce the dose of sedatives, analgesics, and anesthetics administered concomitantly. Intravenous (IV) dexmedetomidine has been successfully used in pediatric laparoscopic surgeries. Studies using IV dexmedetomidine in pediatric urogenital surgeries are lacking. We hypothesized that IV dexmedetomidine as an adjuvant to isoflurane administered as a bolus followed by infusion would provide better hemodynamic stability intraoperatively and better recovery profile in children undergoing laparoscopic SF-2 orchidopexy compared to the standard technique of general anesthesia (GA) supplemented with regional analgesia.
| Materials and Methods|| |
This prospective, randomized controlled study was conducted on thirty children undergoing SF-2 orchidopexy under GA at a tertiary pediatric referral hospital between June 2019 and March 2020.
Institutional ethical committee approval was obtained (institutional review board No. IGICH/ACA/EC/P108/2019-20), and the study was registered under the Clinical Trials Registry of India (REF/2020/05/033572). Children aged between 1.5 and 11 years belonging to American Society of Anesthesiologists (ASA) physical status I and II were included in the study. Children suffering from congenital heart disease, pulmonary disease, or severe obstructive sleep apnea and syndromic association were excluded from the study.
After preanesthetic evaluation, a written informed consent was obtained from the parents. As per the institutional protocol, all children received IV antibiotics preoperatively. Standard nil per oral guidelines were followed. All children were premedicated with injection midazolam 0.05 mg/kg IV in the preoperative holding area.
Standard ASA monitors such as pulse oximetry, capnometry, electrocardiography, and noninvasive blood pressure were attached before induction; baseline parameters were recorded; and IV fluid infusion was started. After preoxygenation, induction was done with propofol 2 mg/kg and fentanyl 2 μg/kg, and intubation was facilitated with atracurium 0.5 mg/kg IV. Paracetamol 15 mg/kg, dexamethasone 0.1 mg/kg, and ondansetron 0.1 mg/kg IV were administered to all children. Anesthesia was maintained with air–oxygen mixture (50:50); isoflurane 1%–2% was titrated to hemodynamic parameters within the range of ± 20% of baseline values; and muscle relaxation with atracurium infusion was done at a dose of 10 μg/kg/h.
Bradycardia was defined as heart rate (HR) <60 beats/min, tachycardia being 20% increase from the baseline HR, hypertension as 20% increase in systolic blood pressure (SBP), and hypotension as 20% decrease from the basal value. Bradycardia was initially managed by the cessation of surgical stimulus and by administering atropine 0.01 mg/kg IV if there was no response to cessation of stimulus by surgeon. Hypotension was managed by concomitantly reducing the fraction of inspired concentration of isoflurane by 0.5% and infusion of IV fluids based on hourly calculations. If there was no response to these measures, the infusion rate of dexmedetomidine was decreased or stopped and the child was excluded from the study. Fentanyl 1 μg/kg was administered if there was tachycardia or hypertension, despite the administration of 1.3 minimum alveolar concentration of isoflurane.
The patients were divided into two groups of 15 each based on computer-generated randomization. Patients belonging to Group D (study group) received dexmedetomidine 1 μg/kg bolus diluted to 10 mL in normal saline over 10 min before pneumo-insufflation of the peritoneum, followed by 0.5 μg/kg/h maintenance infusion, which was continued till the beginning of skin closure. Laparoscopic port sites were infiltrated with levobupivacaine 0.125%. Those in Group C (control group) were administered single-shot epidural analgesia at T12–L1 intervertebral junction using loss of resistance to saline technique, and 0.5 mL/kg levobupivacaine 0.125% was injected. Atracurium infusion was discontinued at the beginning of closure of skin incision, and isoflurane and medical air were cut off at the end of skin closure. Residual neuromuscular blockade was reversed using neostigmine 0.05 mg/kg and glycopyrrolate 0.01 mg/kg. The patients were extubated after meeting the standard extubation criteria.
Patients were assessed for discharge from the postanesthesia care unit (PACU) using Modified Aldrete score [Annexure 1]. A score ≥9 was the discharge criterion used.
The patients were monitored for HR, SBP, oxygen saturation (SpO2), end-tidal carbondioxide (EtCO2), and temperature (temp), which were recorded at induction, intubation, every 5 min for the initial 15 min, and thereafter every 15 min till the end of surgery. Post extubation, the parameters were recorded every 5 min for 15 min followed by every 30 min for 1 h. The extubation quality was graded using Extubation Quality 5-point scale [Annexure 2]. Any incidence of cough, laryngospasm, bronchospasm, or desaturation was noted for a period of 15 min post extubation. SpO2 <93% was documented as desaturation. Post extubation, sedation was evaluated using Ramsay Sedation Scale and emergence delirium using Pediatric Anesthesia Emergence Delirium (PAED) scale (minimal score is 0 and maximal is 20). If PAED score was 10 or more, the child was considered delirious [Annexure 3]. If the child was inconsolable for 5 min with parental presence, midazolam 0.05 mg/kg was administered as rescue medication. Pain was assessed using Faces, Leg, Activity, Cry, Consolability Behavioral pain assessment (FLACC) scale for children up to 7 years and visual analog scale (VAS) for older children [Annexure 4]. Time to first rescue analgesic was noted. Fentanyl IV 1 μg/kg was administered if FLACC score was ≥4 or VAS score was ≥3. Time to discharge from the hospital was documented. The number of intraoperative repeat doses of fentanyl was noted. Any incidence of postoperative nausea and vomiting or other side effects was noted.
The sample size was based on a pilot study. With the power of the study being 80% and confidence limits at 95%, a minimum sample size required to detect 15% difference in HR in addition to a standard deviation (SD) of 12.856 between the study and control groups, was 11 patients in each group. We conducted the study with 15 patients in each group to compensate for possible dropouts. Descriptive and inferential statistical analysis was carried out. Results on continuous measurements were presented on mean ± SD, and results on categorical measurements were presented in number (%). Student's t-test (two tailed, independent) was used to test the significance of the study parameters on a continuous scale for intergroup and intragroup analyses on metric parameters. Levene's test for homogeneity of variance was performed to assess the homogeneity of variance. Chi-square/Fisher's exact test was used to test the significance of the study parameters on a categorical scale between the two groups. Nonparametric data (scores) were expressed as median ± interquartile range and analyzed using the Kruskal–Wallis test. Statistical software SPSS version 24.0 (IBM Inc., Chicago, IL, USA) was used for the data analysis.P < 0.05 was considered statistically significant.
| Results|| |
Both the groups were comparable with respect to demographic characteristics and duration of surgery [Table 1].
Baseline values of both HR and SBP were comparable between the two groups. However, intraoperatively, HR at 60 and 75 min, at extubation and post extubation for 15 min, was statistically significantly lower in Group D (P < 0.05) than Group C and closer to baseline values [Figure 1].
|Figure 1: Heart rate (in beats per minute). Data are presented as mean ± standard deviation *P < 0.05. PE: Post extubation|
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SBP in Group D intraoperatively from 15 to 90 min and at extubation and post extubation for 30 min was lower than those in Group C and was statistically significant (P < 0.05) [Figure 2].
|Figure 2: Systolic blood pressure (in mmHg). Data are presented as mean ± standard deviation *P < 0.05. PE: Post extubation|
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SpO2, EtCO2, and temperature were comparable between both the groups (P > 0.05).
None of the patients in Group D had emergence delirium in comparison with those in Group C where the incidence was 33.3%. Furthermore, significantly lower PAED scores were observed in the study group compared to the control group [Table 2].
|Table 2: Postoperative Paediatric Anaesthesia Emergence Delirium scale (median [interquartile range])|
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Sedation scores were statistically significantly higher in Group D when compared to Group C at 5 and 10 min post extubation (P = 0.0003 and P = 0.33, respectively) [Figure 3].
|Figure 3: Ramsay Sedation Scores. Data are presented as mean ± standard deviation *P < 0.05|
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Pain scores were comparable in the study and control groups beyond 2 h post extubation (P > 0.05). Furthermore, the observed pain scores were higher in the control group compared to that of the study group [Table 3].
|Table 3: Postoperative pain scores (Faces, Leg, Activity, Cry, Consolability Behavioral Pain Assessment scale/visual analog scale) (median [interquartile range])|
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Four patients (26.67%) in the control group required repeat dose of fentanyl intraoperatively. Furthermore, the time to first rescue analgesic in the study group (128.67 ± 33.14 min) was statistically significantly prolonged compared to that of the control group (70 ± 32.13 min) with P = 0.00003.
All children in Group D had smooth extubation with extubation quality score of 1 except for one patient who had mild cough (score 2). However, one child in Group C had poor extubation with laryngospasm (score 5) and had severe coughing and straining (score 4). Two children in Group C also had desaturation. All children responded to treatment. These findings though had no statistical significance have clinical significance because of the poor extubation quality.
The incidence of tachycardia being 33.3% was statistically significant (P = 0.0421) in the control group and was more than the incidence of hypertension (20%). Hypotension was seen in one patient in the study group 15 min post extubation and improved with IV fluid infusion. None of the patients had bradycardia.
None of the patients in both the groups had bronchospasm or postoperative nausea and vomiting or other side effects.
Time to discharge from the hospital was comparable between the two groups (P > 0.05). Time to discharge from the PACU was not compared in the present study.
| Discussion|| |
The findings of this study suggest that IV dexmedetomidine as an adjuvant provides stable hemodynamics intraoperatively and a smoother extubation with a better recovery profile and a longer time to first rescue analgesic without any major adverse effects.
Cryptorchidism means failure in descent of the testes during fetal development from the abdomen into the ipsilateral scrotum. The incidence varies and is about 1%–4.6% in full-term boys and 1.1%–45% in preterm neonates on at least on one side, which makes cryptorchidism the most common anomaly in boys. This anomaly can be bilateral in up to 30% of cases. Congenital UDT descends spontaneously mostly between 2 and 4 months of age due to increased pituitary gonadotropins. Thus, a lower incidence of 1%–2% is seen between 3 and 12 months of life. “Watchful wait” for spontaneous descent is done till the child is 6 months of age. The incidence of nonpalpable testes is 20% of UDT, of which that of intra-abdominal testes is 40%.
Surgery is preferred over hormonal treatment (often used as an adjuvant) for UDT, with orchidopexy having 95% success rate. Two-staged SF procedure has higher success (80%–85%) in the treatment of high intra-abdominal testes. SF Stage-1 surgery includes division of testicular vessels on the affected side to increase the mobility of the testis and a gap of 6–9 months to allow collateralization of the deferential artery. SF Stage-2 involves a combined inguinal and laparoscopic approach to bring the testis down to the scrotum. Thus, management of SF-2 includes anesthetic considerations of both open and laparoscopic surgery in a pediatric patient to the anesthesiologist. With pneumo-insufflation of peritoneum with carbon dioxide (CO2), raised intra-abdominal pressure causes sympathoadrenal response, resulting in increased systemic vascular resistance and an increased PaCO2 is seen due to the absorption of insufflated CO2. Along with the above changes, a decrease in functional residual capacity requiring an increase in minute ventilation due to cephalad shift of diaphragm is noted. In addition, those resulting from patient positional changes, that is, Trendelenburg position, causes an increase in venous return.
Dexmedetomidine is known to cause hypotension and bradycardia when administered as a slow infusion due to a2agonism. Smania et al. in their study found that initial dose of dexmedetomidine at 1 μg/kg followed by a maintenance dose of 0.5 μg/kg/h as an adjuvant to isoflurane anesthesia, in children submitted to videolaparoscopic appendectomy, kept the HR and blood pressure stable, also in periods of heightened surgical stimulation. Similar findings have been observed in the present study with dexmedetomidine at same doses as above, which provided a better recovery profile as well.
Intra- and postoperative analgesia in SF-2 procedure needs multimodal management with opioids, nonsteroidal anti-inflammatory drugs and central neuraxial blockade, or local infiltration at the port site. Dexmedetomidine is known to exert dose-dependent analgesic effects through binding to α2-receptors in the dorsal horn of the spinal cord and the supra-spinal sites by the inhibition of release of substance P. Intraoperative need for less opioids and the advantage of increased time to first rescue analgesic were noticed in patients receiving dexmedetomidine, which is much in accordance with the meta-analysis by Cho et al., on the effectiveness of dexmedetomidine in pediatric tonsillectomy.
Preoperative preparation addresses the issue of increased anxiety associated with multiple surgeries in this subset of patients. Avoidance of preoperative administration of anxiolytics to study the incidence of emergence delirium is unacceptable because anxiety before and during the induction of anesthesia has been associated with an increased risk of postoperative negative behavioral changes apart from emergence delirium. Because of the above reason and as per the institutional practice, midazolam at 0.1 mg/kg was administered as an anxiolytic preoperatively in all patients. The incidence of emergence delirium in the control group in this study was 33.3% in accordance with Ghai et al. who reported an incidence of emergence delirium of 35% in the control group in children undergoing cataract surgery after premedication with oral midazolam 0.5 mg/kg.
In the current study, the PAED scale, the only validated scale for rating emergence delirium, was used. The investigators who proposed the PAED scale assessed children 10 min after awakening. However, the modification used by Ghai et al. in the PAED scale in their study was adopted in this study. The modification was due to the reason that in early stages the children who were asleep were receiving a rating of 4 on the first three items of the PAED scale (i.e., they were not able to make eye contact, they were not aware of the surroundings, and their actions were not purposeful) and children who were asleep were not agitated. These scores were rated as 0. Dexmedetomidine provides sedation and anxiolysis by acting on these receptors in the locus coeruleus of the pons via the reduction in the release of noradrenaline, facilitating the action of inhibitory neurons.
Dexmedetomidine at a dose of 1 μg/kg as bolus followed by infusion at 0.5 μg/kg caused bradycardia in three patients (20%) and hypotension in one (6.67%), which was transient and responded to treatment. However, IV dexmedetomidine at a dose 0.5 μg/kg as a bolus in children undergoing laparoscopic hernia repair had little effect on hemodynamics.
Vagal stimulation caused by insertion of Veress needle or peritoneal stretch with gas insufflation, can result in bradyarrhythmias. Even with GA and neuraxial blockade, laryngospasm and/or bradycardia can occur during spermatic cord manipulation requiring deeper levels of GA during these steps of the procedure. Hence, using dexmedetomidine as an adjuvant can ensure deeper planes by its hypnotic and analgesic action.
Laparoscopy and orchidopexy are associated with an increased risk of postoperative nausea and vomiting due to manipulation of the testis. The use of dexmedetomidine reduces the incidence of postoperative nausea and vomiting by unknown mechanisms. However, nausea and vomiting were not seen in any patients in both the groups because of the use of dual anti-emetics, which is as per the institutional protocol and the supporting literature available.
Kim et al. in their study noted that intraoperative dexmedetomidine 1 μg/kg bolus, followed by 0.1 μg/kg/h infusion, significantly reduced anesthetic requirements and emergence agitation during recovery without delaying discharge in children undergoing ambulatory surgery such as hernioplasty or orchidopexy. In the present study, it was observed that the use of dexmedetomidine infusion did not have any effect on discharge time from the hospital. However, few studies have shown significant prolonged emergence time and PACU discharge time owing to the sedative effect in the immediate postoperative period, but with no complications.
A limitation of this study is that no specific equipment was used to monitor the depth of anesthesia (Bispectral index (BIS) or entropy), and also the possible correlation of hemodynamic perturbations caused by nociceptive stimuli. Lack of evaluation of the correlation between emergence delirium and pain scales may be a cause for bias. Because the study involves small sample size and thus the number of patients recruited for the study may have been inadequate to study the effects of dexmedetomidine, a large multicentric study would be better to extrapolate the above results on a huge population.
| Conclusion|| |
IV dexmedetomidine given as a bolus at a dose of 1 μg/kg followed by infusion at 0.5 μg/kg provides hemodynamic stability intraoperatively with smoother extubation and favorable recovery profile and longer time for rescue analgesics without undue side effects in children undergoing laparoscopic SF stage 2 orchidopexy under GA compared to the standard technique of GA supplemented with regional analgesia.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]