Motoshi Kainuma

Hepatic venous hemoglobin oxygen saturation predicts liver dysfunction after hepatectomy.

A fiberoptic flow-directed catheter inserted into the hepatic vein continuously measures hepatic venous oxygen hemoglobin saturation (ShvO2). This study determined whether intraoperatively measured ShvO2 could predict postoperative serum activities of aminotransferases and patient outcome in 83 patients undergoing hepatectomy. The duration of intraoperative ShvO2 less than or equal to 10, 20, 30, 40, and 50% was calculated in each case. Significant increases in postoperative serum aminotransferases were associated with more than 1, 11, 31, 51, and 181 min of duration of ShvO2 less than or equal to 10, 20, 30, 40, and 50%, respectively. The incidence of postoperative liver failure significantly increased when the duration of ShvO2 less than or equal to 20, 30, and 40% exceeded 11, 31, and 51 min, respectively. The mortality from liver failure was significantly higher when the duration of ShvO2 less than or equal to 30 and 40% exceeded 31 and 51 min, respectively. Therefore, intraoperative monitoring of ShvO2 may predict not only the increase in postoperative serum aminotransferases but also patient outcome in terms of postoperative liver failure after hepatectomy.

Monitoring hepatic venous hemoglobin oxygen saturation in patients undergoing liver surgery

Hepatic venous oxygen saturation (ShvO2) was continuously monitored in 33 consecutive patients undergoing hepatic lobectomy. Fiberoptic pulmonary artery catheters were inserted into the hepatic vein (HV) and in the pulmonary artery through the right internal jugular vein before anesthetic induction. The success rate and mean time for HV catheterization were 100% and 14 min, respectively. The only complication of the procedure was nonsustained atrial or ventricular arrhythmias. Eighteen patients showed decreases in ShvO2 to less than 30% at skin incision, at temporary cessation of hepatic inflow, and/or at surgical manipulation of the liver. Clinical HV catheterization was easy to accomplish and may be a valuable technique in studying the extent and significance of hepatic ischemia during liver surgery.

Effect of acute changes in renal arterial blood flow on urine oxygen tension in dogs.

The relationships between urine oxygen tension (PuO2), PaO2, and acute changes in renal arterial blood flow (RBF) were studied in 19 anesthetized dogs. Indwelling sensors that measure continuously PO2 were inserted into the femoral artery and the ureter. RBF was measured by an electromagnetic flowmeter placed over the renal artery. PuO2 increased significantly from 36 to 72 torr during a stepwise increase in PaO2 from 70 to 180 torr. RBF was decreased in a stepwise fashion from a baseline value of 5.51 to 4.16, 2.13, and finally to .20 ml/kg.min by aortic constriction. PuO2 decreased significantly from a baseline value of 72 torr to 66, 57, and finally to 23 torr. The correlation coefficient between RBF and PuO2 was .84, which was significantly higher than that between RBF and femoral arterial pressure or that between RBF and urinary flow rate. This study demonstrates that PuO2 is a sensitive indicator of acute RBF changes in normal, healthy dogs.

The effect of dobutamine on hepatic blood flow and oxygen supply-uptake ratio during enflurane nitrous oxide anesthesia in humans undergoing liver resection

Liver surgery is often accompanied by hepatic hypoperfusion and hypoxia, and it is controversial whether catecholamines increase hepatic blood flow and oxygen supply. The effects of 3 micrograms.kg-1.min-1 dobutamine on hepatic circulation and oxygen balance were examined in patients anesthetized with enflurane, nitrous oxide, and oxygen for liver surgery. Dobutamine did not cause a significant increase in hepatic arterial blood flow. However, total hepatic blood flow and portal venous blood flow were increased, resulting in an increase in hepatic oxygen delivery (HDO2). The increase in HDO2 was not associated with an improvement of hepatic oxygen supply-uptake ratio, since hepatic oxygen uptake (HVO2) also increased. After hepatectomy, the increases in portal venous blood flow and HDO2 were not accompanied by an increase in HVO2. The stimulation of hepatocellular oxygen metabolism by dobutamine and depressed responsiveness of adrenoceptors on hepatocytes in which metabolism was already augmented are the likely explanation for the different reactions before and after hepatectomy.

Feasibility of Neuromuscular Electrical Stimulation Immediately After Cardiovascular Surgery

OBJECTIVE To determine the safety and feasibility of neuromuscular electrical stimulation (NMES) from postoperative days (PODs) 1 to 5 after cardiovascular surgery. DESIGN Pre-post interventional study. SETTING Surgical intensive care unit and thoracic surgical ward of a university hospital. PARTICIPANTS Consecutive patients (N=144) who underwent cardiovascular surgery were included. Patients with peripheral arterial disease, psychiatric disease, neuromuscular disease, and dementia were excluded. Patients with severe chronic renal failure and those who required prolonged mechanical ventilation after surgery were also excluded because of the possibility of affecting the outcome of a future controlled study. INTERVENTIONS NMES to the lower extremities was implemented from PODs 1 to 5. MAIN OUTCOME MEASURES Feasibility outcomes included compliance, the number of the patients who had changes in systolic blood pressure (BP) >20 mmHg or an increase in heart rate >20 beats/min during NMES, and the incidence of temporary pacemaker malfunction or postoperative cardiac arrhythmias. RESULTS Sixty-eight of 105 eligible patients participated in this study. Sixty-one (89.7%) of them completed NMES sessions. We found no patients who had excessive changes in systolic blood pressure, increased heart rate, or pacemaker malfunction during NMES. Incidence of atrial fibrillation during the study period was 26.9% (7/26) for coronary artery bypass surgery, 18.2% (4/22) for valvular surgery, and 20.0% (4/20) for combined or aortic surgery. No sustained ventricular arrhythmia or ventricular fibrillation was observed. CONCLUSIONS The results of this study demonstrate that NMES can be safely implemented even in patients immediately after cardiovascular surgery.

Extremely prolonged vecuronium clearance in a brain death case.

VECURONIUM is commonly used in the critical care setting. One reason is its relatively short duration of action, which allows clinical assessment of patients within a few hours after discontinuing administration of the drug. We recently encountered a case in which extremely prolonged vecuronium action was observed.

Cervical epidural anaesthesia in carotid artery surgery

The successful anaesthetic management using a cervical epidural technique is reported in three patients undergoing carotid artery surgery. Adequate analgesia was obtained in all cases and the adequacy of cerebral blood flow was easily judged by the patients state of consciousness. Cervical epidural anaesthesia could be a safe and reasonable technique for the management of patients who need carotid artery surgery.

Use of Pulse Oximetry for Monitoring Tracheostomy Tube Obstruction

Experimental studies were performed on dogs for monitoring postoperative tracheostomy tube obstruction using a pulse oximeter. While a 25% obstruction of the cross-sectional area of the tube did not alter the oxygen saturation, obstruction of 40% and above resulted in a drop in the oxygen saturation level which corresponded to the degree of obstruction. The greater the degree of obstruction, the sooner was the fall of oxygen saturation. Therefore a pulse oximeter could be effectively put to use to monitor tracheostomy tube obstruction.