Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
Introduction: Laser Doppler flowmetry has been utilized to assess microvascular blood flow of various organs perioperatively. The purpose of this study is to assess usefulness of laser Doppler flowmetry to monitor microvascular blood flow of the sigmoid colon during abdominal aortic surgery.
Methods: Following IRB approval, 7 patients undergoing abdominal aortic surgery were studied. Anesthesia was induced with etomidate (0.2-0.3 mg/kg), sufentanil (1-2 mg/kg) and vecuronium (0.2-0.3 mg/kg) and maintained with air/oxygen and isoflurane. Each patient had a radial arterial line and a pulmonary artery catheter. The Laser Doppler flow probe (Vasamedics, St. Paul, MN) was placed in contact with the serosa of the sigmoid colon against the mesentery. Sigmoid colonic tissue blood flow by the laser Doppler flowmeter (BPM2 blood perfusion monitor, Vasamedics) in conjunction with mean blood pressure and cardiac output was assessed (1) before aortic cross-clamping, (2) during aortic cross-clamping, and (3) after aortic unclamping following completion of aortic reconstruction. Data were analyzed with repeated measures ANOVA, paired t-test and Pearson correlation matrix. A p<0.05 was considered statistically significant. Results were expressed as mean +/- standard deviation.
Results: Sigmoid colonic tissue blood flow significantly decreased after aortic cross-clamping (28.1 +/- 4.8 ml/min/100g) compared with the value before aortic cross-clamping (51.9 +/- 11.3 ml/min/100g) (p<0.01). Following aortic unclamping, sigmoid colonic tissue blood flow increased back to (41.7 +/- 7.4 ml/min/100g) (p<0.01). Changes in cardiac output were also significant after aortic cross-clamping (4.5 +/- 0.9 l/min) compared with the values before aortic cross-clamping (5.3 +/- 1.1 l/min) and after aortic unclamping (5.7 +/- 1.5 l/min) (p<0.01). However, there were no significant correlations between sigmoid colonic blood flow and cardiac output or mean blood pressure noted. None of these patients developed postoperative ischemic colitis.
Discussion: Sigmoid colonic tissue blood flow decreased after aortic cross-clamping but increased significantly after aortic unclamping. The sigmoid colonic tissue blood flow of 41.7 +/- 7.4 ml/min/100g was quite sufficient to prevent postoperative ischemic colitis. The assessment of sigmoid colonic blood flow by laser Doppler flowmetry is quite useful and may help to prevent postoperative ischemic colitis. (Table 1)
Results: Means +/- SD, *: p < 0.01
1. Am J Phys 236(1)F80-87, 197