Testing the reliability of a new ultrasonic cardiac output monitor, the USCOM, by using aortic flowprobes in anesthetized dogs.
We have used an animal model to test the reliability of a new portable continuous-wave Doppler ultrasonic cardiac output monitor, the USCOM. In six anesthetized dogs, cardiac output was measured with a high-precision transit time ultrasonic flowprobe placed on the ascending aorta. The dogs' cardiac output was increased with a dopamine infusion (0-15 microg x kg(-1) x min(-1)). Simultaneous flowprobe and USCOM cardiac output measurements were made. Up to 64 pairs of readings were collected from each dog. Data were compared by using the Bland and Altman plot method and Lin's concordance correlation coefficient. A total of 319 sets of paired readings were collected. The mean (+/-sd) cardiac output was 2.62 +/- 1.04 L/min, and readings ranged from 0.79 to 5.73 L/min. The mean bias between the 2 sets of readings was -0.0l L/min, with limits of agreement (95% confidence intervals) of -0.34 to 0.31 L/min. This represents a +/-13% error. In five of six dogs, there was a high degree of concordance, or agreement, between the 2 methods, with coefficients >0.9. The USCOM provided reliable measurements of cardiac output over a wide range of values. Clinical trials are needed to validate the device in humans.
Critchley
Lester A
LA
*Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China; and †School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
Peng
Zhi Y
ZY
Fok
Benny S
BS
Lee
Anna
A
Phillips
Robert A
RA
D000818:Animals; D001011:Aorta / Q000502:physiology; D002302:Cardiac Output; D004285:Dogs; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D013815:Thermodilution; D018608:Ultrasonography, Doppler
Connors AF, Speroff T, Dawson NV, et al. The effectiveness of right heart catheterization in the initial care of critically ill patients. JAMA 1996;276:889–97.
Van De Water JM, Miller TW, Vogel RL, et al. Impedance cardiography: the next vital sign technology? Chest 2003;123:2028–33.
Clarke DE, Raffin TA. Thoracic electrical bioimpedance measurement of cardiac output: not ready for prime time. Crit Care Med 1993;21:1111–2.
Weil MH. Electrical bioimpedance for noninvasive measurement of cardiac output. Crit Care Med 1997;25:1455.
Perrino AC Jr, Fleming J, LaMantia KR. Transesophageal Doppler ultrasonography: evidence for improved cardiac output monitoring. Anesth Analg 1990;71:651–7.
Spahn DR, Schmid ER, Tornic M, et al. Noninvasive versus invasive assessment of cardiac output after cardiac surgery: clinical validation. J Cardiothorac Anesth 1990;4:46–59.
Wong DH, Tremper KK, Stemmer EA, et al. Noninvasive cardiac output: simultaneous comparison of two different methods with thermodilution. Anesthesiology 1990;72:784–92.
Schmid ER, Spahn DR, Tornic M. Reliability of a new generation transesophageal Doppler device for cardiac output monitoring. Anesth Analg 1993;77:971–9.
Huntsman LL, Stewart DK, Barnes SR, et al. Noninvasive Doppler determination of cardiac output in man: clinical validation. Circulation 1983;67:593–602.
Nidorf SM, Picard MH, Triulzi MO, et al. New perspectives in the assessment of cardiac chamber dimensions during development and adulthood. J Am Coll Cardiol 1992;19:983–8.
Bland JM, Altman DG. Measuring agreement in method comparison studies. Stat Methods Med Res 1999;8:135–60.
Mantha S, Roizen MF, Fleisher LA, et al. Comparing methods of clinical measurement: reporting standards for Bland and Altman analysis. Anesth Analg 2000;90:593–602.
Lin LI. A concordance correlation coefficient to evaluate reproducibility. Biometrics 1989;45:255–68.
Stetz CW, Miller RG, Kelly GE, Raffin TA. Reliability of the thermodilution method in the determination of cardiac output in clinical practice. Am Rev Respir Dis 1982;126:1001–4.
Critchley LA, Critchley JA. A meta-analysis of studies using bias and precision statistics to compare cardiac output measurement techniques. J Clin Monit Comput 1999;15:85–91.
Edmonds ZV, Mower WR, Lovato LM, Lomeli R. The reliability of vital sign measurements. Ann Emerg Med 2002;39:233–7.
Rutten AJ, Ilsley AH, Skowronski GA, Runciman WB. A comparative study of the measurement of mean arterial blood pressure using automatic oscillometers, arterial cannulation and auscultation. Anaesth Intensive Care 1986;14:58–65.
Bednarik JA, May CN. Evaluation of a transit-time system for the chronic measurement of blood flow in conscious sheep. J Appl Physiol 1995;78:524–30.
Dean DA, Jia CX, Cabreriza SE, et al. Validation study of a new transit time ultrasonic flow probe for continuous great vessel measurements. ASAIO J 1996;42:M671–6.