Pulse contour analysis and transesophageal echocardiography: a comparison of measurements of cardiac output during laparoscopic colon surgery.

BACKGROUND: Pulse wave analysis (PWA) allows cardiac output (CO) measurement after calibration by transpulmonary thermodilution. A PWA system that does not require previous calibration, the FloTrac/Vigileo (FTV), has been recently developed. We compared determinations of CO made with the FTV to simultaneous measurements using transesophageal echocardiography (TEE). METHOD: Ten ASA I-II patients scheduled for laparoscopic colorectal surgery were studied. A radial 20-gauge cannula was inserted and connected to a hemodynamic monitor and a FTV system for PWA and determination of CO (CO(PWA)). TEE CO (CO(TEE)) was determined as previously described. Measurements were made after intubation, 5 min after establishing the lithotomy position, 5 min after establishing pneumoperitoneum, every 30 min, or each time mean arterial blood pressure decreased below basal values. Statistical analysis was made with the Bland and Altman method. RESULTS: Eighty-eight measurements were compared. The CO(TEE) values ranged from 3.23 to 12 Lt/min (mean 6.21 +/- 1.85). Values for CO(PWA) ranged from 2.9 to 8.5 Lt/min (mean 4.84 +/- 1.14). Bias was 1.17 and limits of agreement -2.02 and 4.37. The percentage error between all CO(TEE) and CO(PWA) measurements was 40% (27%-50%) mean (range). CONCLUSION: During laparoscopic colon surgery, clinically important differences were observed between CO determinations made with TEE and FTV.

The volume of lactated Ringer's solution required to maintain preload and cardiac index during open and laparoscopic surgery.

BACKGROUND: Recent studies have emphasized the importance of perioperative fluid restriction. However, fluid restriction regimens may increase the likelihood of insufficient perioperative fluid administration or may result in excess intravascular crystalloid replacement. We postulate that the use of transesophageal echocardiography may reduce the amount of crystalloid administered during open and laparoscopic colorectal surgery. METHODS: Fifteen ASA I and II patients scheduled for open colorectal surgery, and 15 patients scheduled for laparoscopic surgery were studied. Lactated Ringer's solution was infused during the procedures. Left ventricular end diastolic volume index (LVEDVI) and cardiac index were assessed throughout surgery and used to guide the rate of lactated Ringer's solution administration. Statistical analysis was performed with Student's t-test for unpaired samples. RESULTS: The rate of crystalloid administration required to maintain baseline LVEDVI and cardiac index was 5.9 +/- 2 mL x kg(-1) x h(-1) for open surgery and 3.4 +/- 0.8 mL x kg(-1) x h(-1) for laparoscopic surgery (P < 0.01). This slower rate for laparoscopic surgery was offset by the longer surgical duration. CONCLUSION: The rate of crystalloid solution to maintain baseline LVEDVI and cardiac index was greater in open surgery than laparoscopic surgery, and lower than commonly recommended for colorectal surgery.