Agreement and clinical utility of 2 techniques for measuring cardiac output in patients with low cardiac output.
BACKGROUND
The reliability of cardiac output obtained with the bolus technique is a problem.


OBJECTIVE
To compare measurements of cardiac output measured with bolus and continuous techniques in patients with low cardiac output and to determine if measurements obtained with the continuous technique increased the number of subsequent clinical decisions.


METHODS
In 60 intensive care patients, a nurse recorded a single continuous cardiac output measurement and then obtained the mean of 3 consecutive bolus determinations. The medical records of these 60 patients (experimental group) for the next 48 hours and of 60 other patients with regular or mixed venous oximetry catheters (control group) were reviewed to assess the occurrence of cardiac output events and the frequency of clinical decisions based on the events.


RESULTS
Mean cardiac output was 4.46 L/min by the continuous technique and 5.20 L/min by the bolus technique (P = .011) for the experimental group. Median bias between the 2 types of measurements was -0.10 L/min (P = .79). Twenty-three of the pairs (38%) had an absolute percent difference greater than 15%. Of these, 18 (78%) had a higher bolus reading. Treatment decisions per 48 hours were 9.9 for the experimental group and 8.6 for the control group (P = .014). Median length of stay was 2 days less in the experimental group (P = .02), and mean highest cardiac output was 0.81 L/min higher (P = .009).


CONCLUSIONS
Measurements of cardiac output determined with the continuous technique may be more precise than measurements determined with the bolus technique. Continuous cardiac output information increases the number of treatment decisions and actions that may shorten hospital length of stay.
Albert
N M
NM
Division of Nursing, Cleveland Clinic Foundation, Ohio, USA.
Spear
B T
BT
Hammel
J
J
D002302:Cardiac Output / Q000502:physiology*; D002303:Cardiac Output, Low / Q000175:diagnosis* / Q000451:nursing*; D002407:Catheterization, Swan-Ganz; D003422:Critical Care / Q000379:methods; D003657:Decision Making; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012044:Regression Analysis; D015203:Reproducibility of Results; D013815:Thermodilution