|LETTERS TO EDITOR
|Year : 2021 | Volume
| Issue : 1 | Page : 99-100
Flush valve malfunction of a central venous pressure transducer causing inadvertent excessive fluid administration
GN Chennakeshavallu, Sruthi Sankar
Division of Cardiothoracic and Vascular Anesthesia, Meenakshi Multi Speciality Hospital, Thanjavur, Tamil Nadu, India
|Date of Submission||06-Mar-2020|
|Date of Acceptance||16-Aug-2020|
|Date of Web Publication||22-Feb-2021|
Dr. G N Chennakeshavallu
Division of Cardiothoracic and Vascular Anesthesia, Meenakshi Multi Speciality Hospital, Thanjavur - 613 005, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Chennakeshavallu G N, Sankar S. Flush valve malfunction of a central venous pressure transducer causing inadvertent excessive fluid administration. Indian Anaesth Forum 2021;22:99-100
|How to cite this URL:|
Chennakeshavallu G N, Sankar S. Flush valve malfunction of a central venous pressure transducer causing inadvertent excessive fluid administration. Indian Anaesth Forum [serial online] 2021 [cited 2021 May 9];22:99-100. Available from: http://www.theiaforum.org/text.asp?2021/22/1/99/309836
Central venous pressure (CVP) monitoring port may be shared for fluid administration in certain circumstances (e.g., single-lumen catheters or in patients requiring multiple infusion of cardioactive drugs). In such situations, the accuracy of CVP monitoring depends on the rate of fluid administered. We report a rare incident when CVP monitoring line shared for continuous pressure measurement and simultaneous fluid administration led to inadvertent excessive fluid administration due to flush valve of the pressure transducer being fixed in open position.
We inserted a triple lumen central venous catheter (CVC) under local anesthesia in an adult patient posted for off-pump coronary artery bypass grafting (OP-CABG). Due to inadequate peripheral venous access, we shared the CVP monitoring port for concomitant pressure monitoring and fluid administration with three-way stopcock open to both pressure monitoring line and intravenous fluid line. The other two ports of CVC were used for the inotrope/vasopressor and vasodilator infusion, respectively. The CVP was monitored using a pressure transducer (Medex, Smiths Medical, and Mexico) and displayed a reading of 14 mmHg with a fluid rate of approximately 100 ml/h. During verticalization of the heart and with increase in the rate of intravenous fluid, the CVP trace was above the scale and had a reading of 50 mmHg. We observed back flow of blood from the arterial monitoring line and the fluid source in the pressure bag of the flush system was found empty. On searching for the cause, we found the transducer flush valve of CVP line to be in open position which led to inadvertent excessive fluid being pushed into the circulation from the fluid source in the pressure bag. Fortunately, our patient had no signs of fluid overload. The intra- and post-operative course of the patient was uneventful.
Pressure transducers are important components of hemodynamic monitoring. The components required to set up a pressure transducer include a transducer kit with a fluid line, a heparinized fluid bag, mounting plate, pressure infusion bag, and a monitor with a cable to connect the transducer. The transducer kit may contain single or two transducers. A single fluid source and pressure bag may be used to flush all the units simultaneously. The design of the transducer flush valve may vary. The most common designs are a flush valve with a pigtail, which is pulled to flush the tubing and a flush valve with two plastic wings which are squeezed to flush the tubings.
In our case, the movable plastic wing of the flush valve was fixed in open position when the valve was squeezed to flush the system [Figure 1]. This led to unintentional excessive fluid being infused into the circulation within a few minutes because the flush pressures are typically >300 mmHg. Gorlinger et al. have reported markedly increased rinsing flow from the fluid source in the pressure bag due to a faulty pressure transducer. In their report, the high CVP displayed on transduction in patients with normal cardiac function was the clue to identify such a problem. However, in the present case, as the CVP monitoring line was used for fluid bolus administration simultaneously and with adoption of Trendelenburg position during OP-CABG, we did not rely on the CVP waveform and pressure reading for monitoring intravascular volume status. Although such large volume infusion within a short span did not have any consequences in our patient, this could have great impact in pediatric patients subjecting them to complications of volume overload.
|Figure 1: Representative image showing the arterial and central venous pressure transducer. The flush valve of central venous pressure transducer is fixed in open position (red arrow). A single flush line is connected to both arterial and central venous pressure transducer (white arrow)|
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Therefore, we conclude that clinicians should be aware of such problems associated with pressure transducer and constantly vigilant toward the trace and readings displayed by the transducer. When pressure transducers are used properly, they are safe and a valuable tool.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Ho AM, Dion PW, Karmakar MK, Jenkins CR. Accuracy of central venous pressure monitoring during simultaneous continuous infusion through the same catheter. Anaesthesia 2005;60:1027-30.
Ortega R, Connor C, Kotova F, Deng W, Lacerra C. Use of pressure transducers. N Engl J Med 2017;376:e26.
Gorlinger K, Kehren CJ, Peters J. Mini-epidemic of erroneous central venous pressure measurements resulting from the malposition of a specific part of a pressure transducer system. Anesthesiology 2009;110:1417-8.