Continuous measurement of cardiac output using stochastic system identification techniques.

Indicator dilutions techniques offer the most reliable methods of determining clinical cardiac output because of the elastic nature of the cardiac vessels. A catheter-mounted beating filament affords a simple means of supplying "heat" indicator, but is power and temperature limited because of possible patient injury. A stochastic signal processing method using pseudorandom binary infusion of heat offers a process of enhancing the signal to noise sufficiently to facilitate a computation of cardiac output over a reasonable time period (5 min) with a clinically acceptable error.

Continuous thermodilution cardiac output measurement in sheep.

A technique has been developed to continuously measure cardiac output by means of the principles of thermodilution. Pulmonary artery catheters were modified by placing a 10 cm filament near the usual injectate port. Small amounts of heat were infused according to a randomly repeating binary on-off sequence.

Evaluation of a continuous thermodilution cardiac output catheter.

The authors evaluated a thermodilution catheter designed to continuously measure cardiac output (CO). A 10 cm long surface heating element is positioned in a Swan-Ganz catheter corresponding to a right atrial-ventricular site. Heat is repetitively deposited into flowing blood in a unique, pseudorandom binary form.

Continuous thermodilution cardiac output measurement in intensive care unit patients.

A new continuous thermodilution cardiac output measurement technique and companion flow-directed pulmonary artery catheter were evaluated in intensive care unit (ICU) patients. Continuous cardiac output was monitored for 6 hours in each patient, and, at selected intervals, a series of bolus thermodilution cardiac output determinations was made and averaged for comparison. A total of 222 data pairs was obtained in 54 patients.