PURPOSE: Pulmonary artery (PA) hypertension is a serious disease that remains underdiagnosed. Bedside screening for undiagnosed PA hypertension by non-cardiologist sonographers may be possible with focused echocardiography. It is unknown whether trained medical residents can use color and continuous wave Doppler to estimate PA pressures that correlate well with technologist-performed and cardiologist-read echocardiographic determinations.
METHODS: Second and third year medical residents on elective in critical care ultrasound were trained in a standardized and validated 5 hour lecture module for interpretation and a 3 hour practice module for acquisition in focused echocardiography. Consecutive medical ICU or intermediate care patients awaiting or having had formal echocardiography, in which PA systolic pressure is routinely calculated, were enrolled. Residents evaluated for tricuspid regurgitation in parasternal short axis, apical four chamber or subcostal views. If significant regurgitation was present, the resident obtained a maximal velocity with continuous wave Doppler, and software on the devices (Sonosite M turbo and Zonare) allowed calculation of a right ventricular systolic pressure from the modified Bernoulli equation. Residents then evaluated the inferior vena cava diameter and collapsibility to determine right atrial pressure which was added to determine PA systolic pressure. Residents also evaluated right ventricular dimension and contractility.
RESULTS: We present a preliminary analysis of our results. Four residents performed a total of 20 studies. Kappa between resident and cardiologist for diagnosis of PA hypertension was 0.60 (standard error 0.18), corresponding to good inter-observer agreement. Residents correctly identified 9 out of 10 cases of PA hypertension diagnosed by formal echocardiography.
CONCLUSIONS: After an eight hour training course, medical resident determination of elevated PA systolic pressure showed good inter-observer agreement with PA pressure obtained on comprehensive echocardiography read by board-certified cardiologists.
CLINICAL IMPLICATIONS: Medical residents can be taught to screen for PA hypertension noninvasively in the critically ill after an eight hour course in focused echocardiography.
DISCLOSURE: The following authors have nothing to disclose: Jonathan Caronia, Klaus Lessnau, Babak Tofighi, Jon Jordan, Bushra Mina
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