by Kris Nelson, RN, CCRN, CFRN, EMT-P; Survival Flight Nurse
The Survival Flight team at Michigan Medicine transports a small number of high risk obstetrical patients (on average, 5 patients per calendar year). Though low in volume, these transports are considered high risk for both the mother and the fetus given the environment of transport vehicle (rotor wing, fixed wing) and the limited monitoring capabilities specifically for fetal well-being during the transport.
These transports present challenges to the medical crews relative to concerns as simple as patient comfort when considering temperature, ambient noise, vibration and communication, to actual monitoring of maternal blood pressure, heart rate and the overall clinical picture. Additionally, transports of these patients frequently include the inability to monitor fetal heart rate (FHR) during the transport phase. This is of great concern, particularly since these obstetrical patients are considered “high risk.”
FHR monitoring can be accomplished utilizing commercial FHR monitors. However, the cost of those monitors are often prohibitive compared to the volume of transports performed. They require specific testing (Electromagnetic Interference or “EMI”) per Federal Aviation Administration regulations. They can also be very bulky, heavy and not practical for the transport environment given the space limitations, weight restrictions, environmental factors.
Commercially available hand-held dopplers are reasonably priced. However, the ability to hear the Doppler signal (much like using a stethoscope) is virtually impossible as the air medical transport environment is loud with aircraft noise, communications between crew members and ground control and other aircraft. This is in addition to the fact that the medical crew members are helmeted. Monitoring FHR can and should be documented prior to transport (and on arrival) but there has been no practical method to do so during transport which remains a critical time frame compelling investigation into a simple and cost effective method to monitor FHR during the transport itself.
The Flight Nurses on the Survival Flight team are trained and certified under the Medical Director to perform “Point of Care Ultrasound” (POCUS) exams in the pre-hospital and transport phase, and have been doing these exams for the last two years. These assessments have concentrated on utilizing the FAST and RUSH exams, performing LUNG and IVC exams in conjunction with the clinical examinations of the patients that they transport. Using the portable SonoSite IViz (FUJIFILM SonoSite, Inc.) device, the flight crews have become adept and knowledgeable in its use. A review of the IViz operating manual revealed that the device had the capability to measure FHR.
Testing was done with the IViz in the “OB mode” to scan for and then calculate the FHR on both a simulated FHR model and on a pregnant volunteer (18-week gestation). Repeated testing on both models proved that the IViz was excellent for accurately detecting and calculating as well as recording FHR. The SonoSite IViz should prove to be an easy device to utilize for our needs and a dependable method for monitoring FHR in the transport environment.
The following video provides a brief and simplified tutorial of this procedure:
We want to thank the University of Michigan Emergency Medicine Clinical Ultrasound Faculty for their tireless efforts in providing instruction and mentorship to the Survival Flight nurses as we attempt to fully integrate the use of ultrasound into our clinical practice.