Continuous versus intermittent thermodilution cardiac output measurement during orthotopic liver transplantation

Abstract

SummaryWe evaluated intermittent and continuous thermodilution cardiac output data in 12 patients undergoing orthotopic liver transplantation. Measurements were performed at 16 predefined time points between induction of anaesthesia and 3 h after reperfusion of the liver graft. Cardiac output measurements yielded 192 data pairs (intermittent cardiac output range: 1.8-18.9 l.min ¹1 , continuous cardiac output range: 3.3-20.0 l.min ¹1 ). During most of the procedure the correlation between intermittent and continuous cardiac output measurements was significant (r = 0.87, p < 0.0001), accompanied with a bias of ¹0.240 l.min ¹1 and a degree of precision of 1.789 l.min ¹1 (< 10.0 l.min ¹1 : 1.137 l.min ¹1 , Ն10.0 l.min ¹1 : 2.220 l.min ¹1 ). However, in the early phases after caval clamping and after reperfusion, accuracy was not acceptable. Only during these phases did the difference between the mean values of pulmonary artery blood temperature and rectal temperature increase (after caval clamping) or decrease (after reperfusion). In conclusion, despite acceptable levels of accuracy and precision between intermittent and continuous cardiac output measurement under stable conditions, both methods showed markedly decreased accuracy and precision in the early phases after caval clamping and after reperfusion, possibly owing to increased thermal noise.

Continuous cardiac output monitoring - further applications of the thermodilution principle

“…An excellent bias (±0.0213 ± 0.59 l/min) was detected before and more than 45 min after CPB. In agreement with our findings in cardiac patients, the discrepancy between BCO and CCO occurred when rectal temperature and pulmonary artery blood temperature showed opposite slopes [15]. During this period, but not during the ensuing time points, the central blood temperature decreased while the rectal temperature increased, indicating thermal equilibration between central and cooler peripheral compartments.…”

“…Our group evaluated BCO versus CCO in 30 patients undergoing coronary artery bypass surgery with the use of a hypothermic cardiopulmonary bypass (CPB) technique [14]. This hypothesis was supported by a subsequent study in 12 patients undergoing orthotopic liver transplantation [15]. There was, however, a lack of agreement up to 45 min after CPB.…”

Cardiac Output Monitoring Using Indicator-Dilution Techniques: Basics, Limits, and Perspectives

“…CPATD CO measurements have been shown to correlate well with IB-PATD CO measurements under a wide range of CO in patients [62][63][64][65][66][67][68] (Table 1) and in animal models. 69,70 CPATD CO measurements were also compared with electromagnetometry and ultrasound using aortic flowprobes, representing most closely a "gold standard" for continuous determination of CO, in cardiac surgery patients, as well as in the presence of an LV assist device, allowing predetermination of aortic blood flow.…”

“…74 Although CPATD and IB-PATD rely on the same principle of thermodilution, extreme temperature variations can cause poor correlation between them. In patients recovering from hypothermia after cardiopulmonary bypass 75 or liver transplantation, 65 IB-PATD CO exceeded CPATD CO significantly until resolution of hypothermia. Indeed, IB-PATD CO may be less sensitive to thermal noise because the magnitude of the temperature change induced by the single cold saline bolus is much greater than the small heat signals induced with CPATD CO.…”

Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graft

“…Continuous cardiac output was collected every minute by a thermal catheter (Swan‐Ganz Baxter 744HF75, Deerfield, IL). At each collection time, data were obtained when catheter thermal noise disappeared,11 usually between 5 and 8 minutes after each change. In all determinations, we choose the lowest values for mean systemic blood pressure and the highest values for mean pulmonary blood pressure within 10 minutes after each point of the study.…”