Sphygmomanometer for Invasive Blood Pressure Monitoring in a Medical Mission

In patients undergoing high-risk surgery or presenting with major comorbidities, invasive arterial pressure monitoring is often used as the standard of care;¹  however, its availability one of the challenges an anesthesiologist may face in remote areas.²  After ultraviolet disinfection, a sphygmomanometer and an intravenous infusion set can be assembled to deliver effective continuous arterial pressure monitoring without a functioning monitor (panel A).

This setup described does not allow for a zeroing process. Instead, the heparin solution is injected through the stopcock to make the air column pressure in the tube (shown by the sphygmomanometer) reach the level of the patient’s mean arterial pressure (panel B). When the system is opened to the patient, it can be seen that the sphygmomanometer pointer fluctuates with the cardiac cycle. Its advantages include beat-to-beat blood pressure monitoring and accurate blood pressure reading at low pressures.³  It has the same complications as conventional arterial monitoring, like thrombosis and air embolus. Constant attention is needed to keep the catheter patent, and the tube should be flushed frequently. It also should be noted that this setup can only reflect the trend of mean arterial pressure rather than systolic and diastolic pressures. Simultaneous non-invasive blood pressure monitoring is recommended to overcome this shortcoming. None of these limitations should take away from the usefulness of this device in the field, because only simple pieces of equipment are needed, and the overall trend of pressure will be accurate.