Bw. Bottiger et al., CONTINUOUS VERSUS INTERMITTENT CARDIAC-OUTPUT MEASUREMENT IN CARDIAC SURGICAL PATIENTS UNDERGOING HYPOTHERMIC CARDIOPULMONARY BYPASS, Journal of cardiothoracic and vascular anesthesia, 9(4), 1995, pp. 405-411
Citations number
30
Categorie Soggetti
Anesthesiology,"Peripheal Vascular Diseas","Cardiac & Cardiovascular System
Objective: Continuous thermodilution cardiac output (CCO) measurement
was clinically evaluated in patients who underwent coronary revascular
ization using hypothermic low-flow, low-pressure cardiopulmonary bypas
s (CPB). Design: Prospective study. Setting: University hospital setti
ng. Participants: 30 cardiac surgical patients. interventions: CCO was
correlated to standard bolus cardiac output (ICO) obtained at end-exp
iration. Interventions: CCO was correlated to standard bolus thermodil
ution cardiac output (ICO) obtained at end-expiration. Measurements an
d Main Results: Measurements were taken at selected time points (n = 1
8) before anesthesia induction, before CPB, and 5 minutes to 12 hours
after CPB. A total of 540 data pairs were thus obtained. ICO ranged fr
om 1.9 to 9.9 L/min, CCO from 1.5 to 9.9 L/min. Correlation between IC
O and CCO was highly significant (r = 0.872; p < 0.01), accompanied by
an excellent accuracy (bias -0.0213 L) and precision (0.59 L) before
CPB and more than 45 minutes after CPB. However, during the first 45 m
inutes after CPB, there was no correlation (r = 0.273) between ICO and
CCO, and ICO tended to be relatively high, whereas CCO measurements s
howed relatively low values. During the first 45 minutes after hypothe
rmic CPB, but not during the ensuing time period, central blood temper
ature decreased, which may be interpreted as a lack of thermal equilib
ration between central and peripheral compartments. It is hypothesized
that thermal instability in combination with increased respiratory va
riations in pulmonary artery blood temperature caused inhomogenous rew
arming of different body sites and might be the main reason for the la
ck of correlation between ICO and CCO. Conclusions: Despite an excelle
nt correlation, accuracy, and precision between CCO and ICO before CPB
and more than 45 minutes after hypothermic CPB, a lack of correlation
in the early phase after CPB has been found. Further investigation is
needed to elucidate tire underlying cause of these findings and to cl
arify whether ICO or CCO or both fail to represent the real cardiac ou
tput up to 45 minutes after weaning from hypothermic CPB. Copyright (C
) 1995 by W.B. Saunders Company