The effect of anaesthesia and aortic clamping on cardiac output measurement using arterial pulse power analysis during aortic aneurysm repair*

Abstract

SummaryThe LiDCO TM plus monitor (LiDCO Ltd, Cambridge, UK) uses pulse contour analysis of the arterial pressure waveform to indicate changes in stroke volume and cardiac output. Calibration against a lithium indicator dilution method is required to permit display of absolute values in addition to trends. The effect of haemodynamic changes during anaesthesia and surgery on this calibration factor has not previously been studied. Therefore, we investigated whether it remained constant during elective abdominal aortic aneurysm surgery in 15 patients. Comparison between the calibration factor values at different time points was made by repeated recalibration throughout the peri-operative period. Calibration factor increased by a mean of 53% after anaesthesia (epidural plus general) (p = 0.03) and decreased by a mean of 40% after aortic clamping (p = 0.0001). Recalibration should be undertaken after induction of anaesthesia and after aortic clamping if absolute values of cardiac output and stroke volume are required.

Validation of cardiac output measurement with the LiDCOTM pulse contour system in patients with impaired left ventricular function after cardiac surgery*

“…Their results showed a wide range of limits of agreement and they concluded that LiDCO did not accurately predict rapid decreases in cardiac output or the effects of fluid resuscitation in dogs. Beattie and co-workers also observed an underestimation of thermodilution cardiac output using LiDCO after induction of general and epidural anaesthesia with associated abrupt drops in afterload [22]. Both groups recommended frequent recalibration after decreases in cardiac pre-load and afterload as well as following suspected deterioration in ventricular contractility.…”

Less invasive methods of advanced hemodynamic monitoring: principles, devices, and their role in the perioperative hemodynamic optimization

“…This good correlation was corroborated by Costa et al [27] when they validated the LidCOplus against intermittent thermodilution measurements in patients with hyperdynamic conditions. On the other hand, the uncalibrated pulse power analysis using the Pulse CO algorithm performed less well when used in comparison to the PAC based thermodilution in patients undergoing CABG [28] or when used in very dynamic conditions such as the clamping and unclamping of the aorta in AAA surgery [29]. Concluding, the LidCOplus technology appears to be a reliable substitute to the more invasive thermodilution method via the PAC, provided that the system is calibrated in regular intervals when an absolute value rather than a simple trend of the CO is required.…”

Arterial pressure waveform analysis versus thermodilution cardiac output measurement during open abdominal aortic aneurysm repair

“…3,7 Studies in patients with low systemic vascular resistance (SVR), such as sepsis and liver failure, and studies during rapid haemodynamic change, show conflicting results. 17,18 In addition, reperfusion of the lower extremities after a period of ischaemia may cause an inflammatory response, decreasing vascular resistance. 17,18 In addition, reperfusion of the lower extremities after a period of ischaemia may cause an inflammatory response, decreasing vascular resistance.…”