Am. J. Respir. Crit. Care Med., Vol 155, No. 1, Jan 1997, 26-31.
Noninvasive monitoring of cardiac output in critically ill patients with thoracocardiography
KE Bloch, PC Baumann, R Stocker and EW Russi
Department of Internal Medicine, University Hospital of Zurich, Switzerland.
Thoracocardiography noninvasively estimates changes in cardiac output by
recording ventricular volume curves from an inductive plethysmographic
transducer placed around the chest near the xiphoid process. We evaluated
performance of thoracocardiography for estimation of cardiac output in 21
critically ill patients in comparison to thermodilution. A total of 201
paired cardiac output measurements were obtained over periods of 35 to 254
min. Since thoracocardiography tracks relative changes in cardiac output
but does not provide absolute values, the first cardiac output by
thermodilution in each patient was used to calibrate thoracocardiography
for comparisons of subsequent cardiac output estimates to thermodilution.
The mean difference (bias) of cardiac output (thoracocardiography -
thermodilution) was 0.0 L/min, the limits of agreement (bias +/- 2 SD)
included a range from -1.5 to +1.6 L/min. For estimations of relative
changes in cardiac output by thoracocardiography and thermodilution the
bias was 0%, and the limits of agreement -21 and +22%. We conclude that
thoracocardiography is a promising noninvasive technique for monitoring
cardiac output in critically ill patients.
