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Biomedical subjects

K Shibutani

Publications and source records attributed to K Shibutani.

At least 37 records · Page 2Linked to original sources
PubMed1987

Critical level of oxygen delivery after cardiopulmonary bypass.

The relationship between oxygen uptake (Vo2) and delivery (Do2) was examined in 64 patients immediately after cardiopulmonary bypass. In 44 patients with lactate levels below 2.5 mmol/L, Vo2 decreased proportionally when Do2 decreased below 300 ml/min X m2. At a Do2 over this level, Vo2 plateaued at 105 +/- 13 (SD) ml/min X m2. In a contrasting group of 22 patients with blood lactate levels above 2.5 mmol/L, Vo2 changes depended on changes in Do2 both alone and below 300 ml/min X m2.

Cardiopulmonary Bypass↗
PubMed1986

Effects of intermittent positive-pressure ventilation on cardiac output measurements by thermodilution.

Sequential thermodilution measurements of cardiac output in mechanically ventilated patients undergoing cardiac surgery demonstrated a cyclic modulation which correlated with changes in airway pressure, and was not affected by opening the pericardium. There was no satisfactory point for single measurements, which suggests that random thermodilution measurements of cardiac output during intermittent positive-pressure ventilation should be avoided, even when triplicate measurements are performed. To estimate the mean cardiac output, at least two measurements should be made at predetermined points of the ventilatory cycle. We recommend paired measurements at midinspiration and end-expiration.

Adult↗
PubMed1983

Critical level of oxygen delivery in anesthetized man.

Fifty-eight patients studied were anesthetized with diazepam, pancuronium, and a moderate dose of fentanyl; 99 sets of multiple hemodynamic variables were measured after sternotomy and before cardiopulmonary bypass. The relationship between oxygen consumption (VO2) and oxygen delivery (DO2) was studied. The critical value of DO2 was identified to be 330 ml/min X M2 or 8.2 ml/min X kg by an analysis of the regression lines. When DO2 was less than 330 ml/min X M2, the value of VO2 decreased in proportion to a decrease in DO2 and VO2 was expressed as: VO2 = 0.36 X DO2 - 11.20 (n = 30, r = 0.77, p less than 10(-6). At DO2 greater than 330 ml/min X M2, VO2 values plateaued at 109 +/- 16 (SD): n = 69; r = -0.02, p greater than 0.05; while mixed venous oxygen tension (PVO2) decreased in proportion to the decrease in DO2, suggesting compensatory increase of oxygen extraction. A decrease of VO2 at DO2 less than 330 ml/min X M2 suggests tissue oxygen deprivation occurred.

Adult↗
PubMed1982

Hemodynamic and respiratory changes in surgery of the morbidly obese.

The risk of surgery for the morbidly obese is well known. Suprisingly little information is available regarding the hemodynamic changes during surgery. This study provides data on this important subject and compares them with those of normal nonobese patients. Obese patients demonstrated signifying elevated preoperative, intraoperative, and postoperative right atrial, mean pulmonary artery, and pulmonary artery wedge pressures. Preoperatively, hemodynamic variables were in the high range of normal in obese patients. Significantly greater decreases in cardiac index, right ventricular stroke work (RVSW), and left ventricular stroke work (LVSW) were noticed intraoperatively. Although the RVSW returned to baseline values in the postoperative period, the cardiac index and LVSW remained depressed. Left ventricular function as assessed by Sarnoff curves demonstrated persistent shifts to the right during and after operation. No such shifts were noticed in nonobese patients. Although they were hemodynamically stable and without any other clinical evidence of cardiac abnormality, asymptomatic obese patients had reduced left ventricular contractility (LVSW/pulmonary artery wedge [PAW] pressure ratio) even in the resting state. Obese patients reacted to the stress of surgery and anesthesia by a more specific left ventricular dysfunction that was greater after intubation and in the immediate postoperative period.

Adolescent↗