Comparison of Cardiac Output Measurement by Noninvasive Method with Electrical Cardiometry and Invasive Method with Thermodilution Technique in Patients Undergoing Coronary Artery Bypass Grafting

Objective: This study was conducted to compare the cardiac output by using Electrical Cardiometry (EC), a noninvasive method of continuous cardiac output monitoring during cardiac surgery with pulmonary artery catheter (PAC) derived cardiac output. Design: Prospective observational clinical study. Setting: Cardiac surgery operating room of a tertiary care cardiac center. Participants: Twenty five patients undergoing coronary artery bypass surgery with cardiopulmonary bypass. Measurements and Main Results: A total of 150 double data of cardiac output were compared with Thermodilution Cardiac Output (TDCO) and Thoracic Electrical Bioimpedance (TEBCO). The TDCO value ranges from 1.8-6.9 litre·min-1 with a mean of 4.39 ± 1.16 litre·min-1 and TEBCO ranges from 1.8-7.1 litre·min-1 with a mean of 4.21 ± 1.16 litre·min-1. The averaged Bland-Altman analysis for TDCO and TEBCO revealed that a mean bias was 0.18 and limit of agreement was -1.25 - 0.89 litre·min-1 and the percentage error (PE) ranged from 22%-32%. The precision for the TDCO was measured to be ±16.2% and the precision for TEBCO was ±19.6%. Receiver Operating Characteristic (ROC) curve analysis between TDCO and TEBCO with a cutoff of 15% shows a sensitivity of 84% and specificity of 63 and area under ROC curve of 0.80. Mountain plot between TDCO and TEBCO shows that a median percentile is 0.25 and value of 97.5 percentile is 1.525. Conclusions: The present study indicates that the electric cardiometry device yields numerically comparable results to cardiac outputs derived from the PAC during the cardiac surgery. Therefore, electrical cardiometry can be used to evaluate haemodynamic variables with clinically acceptable accuracy, when invasive methods are to be avoided or not available.

The Effects of Etomidate and Propofol Induction on Hemodynamic and Endocrine Response in Patients Undergoing Coronary Artery Bypass Graft Surgery on Cardiopulmonary Bypass

Aim: To compare the effects of propofol and etomidate induction on hemodynamic parameters and serum cortisol levels in patients with normal left ventricular function undergoing elective coronary artery bypass graft surgery on cardiopulmonary bypass. Material and Method: After approval from the Institute Ethics committee hundred American Society of Anesthesiologists (ASA) grade II or III patients undergoing scheduled coronary artery bypass surgery on cardiopulmonary bypass were enrolled in the study. Patients were allocated randomly to receive either propofol or etomidate for anesthesia induction. Anesthesia was maintained in both groups with sevoflurane, vecuronium bromide for muscle relaxation (0.1 mg/kg, boluses) and fentanyl up to a total dose of 20 mcg/kg. Result: The baseline serum cortisol values were within normal limits in both the groups. The serum cortisol levels in the propofol group increased more than two fold, whereas the values in the etomidate group decreased by close to fifty percent on weaning from cardiopulmonary bypass (CPB). There was no significant difference in serum cortisol levels in the two groups at twenty-four hours after induction, although the values were close to double the baseline levels. Hemodynamically, etomidate group was more stable than propofol group following induction of anesthesia (P < 0.05). Conclusion: The surge in serum cortisol levels on the initiation of CPB seen after the use of propofol is prevented by the use of etomidate. Serum cortisol levels in both groups are well above the baseline at twenty-four hours without any untoward effects. Etomidate provides more stable hemodynamic parameters when used for induction of anesthesia as compared to propofol.