Feasibility of preclinical cardiac output and systemic vascular resistance in HEMS in thoracic pain--the ultrasonic cardiac output monitor.

BACKGROUND: Cardiac output (CO) and systemic vascular resistance (SVR) are important hemodynamic parameters in emergency patients and for clinical early goal-directed therapy. This study evaluated the feasibility of CO and SVR determination using preclinical continuous wave Doppler ultrasound in a helicopter emergency medical service (HEMS) on emergency patients presenting with or without thoracic pain as a pilot observational study.

METHODS: Forty-four consecutive medical emergency patients (62.8 +/- 22 years of age, 23 males) were classified at the scene as with (15 patients, 69 +/- 14 years of age, 40% male) or without (29 patients, 60 +/- 25 years of age, 59% male) thoracic pain by an emergency physician. Hemodynamic parameters were determined based on continuous wave Doppler noninvasively (USCOM, Sydney, Australia): stroke volume (SV), CO, cardiac index (CI), minute distance (MD), and SVR.

RESULTS: Noninvasive SV, MD, CO, CI, and SVR determination is feasible using preclinical ultrasound in HEMS. Thoracic pain patients had higher SVR (2,709 +/- 891 vs 1,499 +/- 661 dyne*sec*cm-5) and lower CO/CI (3.37 +/- 1.1 vs 5.06 +/- 2.9 L/min, CI: 1.67 +/- 0.58 vs 3.18 +/- 1.34 L/min/m2) as well as a reduced aortic minute distance (11.2 +/- 3.3 m/min vs 19.1 +/- 8 m/min, P = .001) than patients without thoracic pain. Highest cardiac outputs were measured during and within 30 minutes after seizures (n = 5, 7.5 +/- 3.05 L/min). The range of CO measured in six cardiopulmonary resuscitation patients was 2.7 to 12 L/min; the level of CO was not associated with the establishing of sustained circulation.

CONCLUSIONS: Determining SV, CO/CI, and SVR in different emergency situations in HEMS using rapid CW Doppler ultrasound is feasible. Thoracic pain patients have increased SVR and lower CO/CI and reduced aortic minute distance than do non-thoracic pain patients in the preclinical setting.