Yoshiro Hayakawa

Perioperative monitoring of fluid responsiveness after esophageal surgery using stroke volume variation

Presented at:The 107th Annual Congress of Japan Surgical Society, Osaka International Convention Center, Japan, 11–13 April 2007. Objective: To assess the utility of a new arterial pressure-based cardiac output (FloTrac™) and central venous oximetry (PreSep™) monitoring system in the perioperative management of patients undergoing radical esophagectomy. Case series: From May 2006, a new analyzing device (Vigileo™ monitor; Edwards Lifesciences LLC, Tokyo, Japan), which can be used in combination with the FloTrac™ and PreSep™ sensors, has been used in nine patients who have undergone radical operations for thoracic esophageal cancer at our hospital. Stroke volume variation (SVV), calculated for each respiratory cycle and displayed on the Vigileo monitor, precisely predicted intravascular hypovolemia. The maximum SVV of patients who needed fluid resuscitation was significantly higher than that of patients who had a stable circulation. The mean value of the maximum SVV in the patient with or without fluid resuscitation was 25 ± 6.9 and 13 ± 1.4%, respectively (p < 0.04). In addition, continuous monitoring of central venous oxygen saturation enabled evaluation of oxygen supply to tissues to aid in determining the need for red blood cell transfusion. The Vigileo monitor (with Flo Trac and PreSep sensors) provided reliable information for the perioperative management of high-risk patients after highly invasive general surgery without the need for an invasive central or pulmonary catheter.

Effects of ligation and reperfusion of hepatic afferent vessels on the composition of liver cell membranes in the rat : 1H- and 31P-magnetic resonance spectroscopic analysis

Biochemical changes that occur within hepatic tissue of the rat during ischemia and subsequent reperfusion were investigated using magnetic resonance spectroscopy of liver extracts. Hepatic ischemia was produced in the rat by a continuous clamping of the left branches of the hepatic artery and portal vein. In the reperfusion experiments, the vascular clamps were released after 30 or 120 min of ischemic periods. At the end of the periods of ischemia and/or reperfusion, the left and middle hepatic lobes were dissected and processed for subsequent 1H‐MRS and 31P‐MRS analyses. Phosphatidylcholine, sphingomyelin, phosphatidic acid and phos‐ phatidylethanolamine contents all showed reduction of about 30% after 120 min of ischemia. In contrast, the content of lysophosphatidylcholine showed relatively small changes following ischemia. Ten minutes after initiation of reperfusion, further decline of the total phospholipid content resulting in as much as 42% reduction was observed. Then it recovered to nearly the control level when ischemia was for 30 min, but to only 65% of the control level when ischemia was for 120 min. The cholesterol/‐N‐(CH3)3 ratio, generally regarded as a parameter for membrane fluidity, showed about a 40% increase when ischemia was for 120 min, a change toward decreased membrane fluidity. These results appear to reflect ischemia/reperfusion‐induced changes of membrane phospholipid metabolism