Nobuo Nishimura

Respiratory changes after major burn injury

In 32 major burn patients, routine respiratory measurements and blood gases analysis were performed. Striking differences were found between survivors and nonsurvivors in these variables. Marked increases in minute volume and respiratory rate were observed in nonsurvivors starting from the 6th day postburn, while PaCO2 increased with larger tidal and minute volumes. At the same time, PaO2 was lower than in survivors. In survivors, the closing volume, maximum mid-expiratory flow rate, and peak flow rate were lower than the predicted normal values. This may indicate that after major burn injury, ventilatory power decreased and some pathological changes occurred in small airways and alveoli without apparent pulmonary complications. Marked differences in the changes of respiratory rate and min volume between survivors and nonsurvivors may indicate the value of simple respiratory measurements for prediction of outcome in burn patients.

Cardiovascular changes in the terminal stage of disease

In 11 patients with brain death, we measured cardiovascular parameters until cardiac arrest. After withdrawal of vasopressors, we observed marked falls in the cardiac output, systemic vascular resistance, heart rate and arterial pressure. In consequence, there was a marked decrease in oxygen delivery and the fall in arterial pressure established a vicious circle and circulatory death ensued. Most pronounced changes were left heart dysfunction and a fall in systemic vascular resistance. On the other hand, depression of the right side of the heart was half of that of left side, and the pulmonary circulation and volume status were well maintained until death. At the same time we found in these patients that body temperature and organ function except that of the brain were well maintained in brain dead patients. For resuscitation of apparently dead patients one must maintain not only cardiac functions but also systemic vascular functions.

Changes of hemodynamics and O2 transport associated with the perfluorochemical blood substitute, Fluosol-DA.

Hemodynamic, arterial O2 tension (Pao2) and transcutaneous O2 tension (PtcO2) changes associated with the infusion of 500 ml of Fluosol-DA were evaluated in 14 decerebrated patients. Flow-directed pulmonary artery catheters and the Clark-type oxygen electrode manufactured by Hoffmann-La Roche were utilized. The marked improvement of cardiovascular variables along with marked increases in Pao2 and PtcO2 may indicate a marked increase in skin circulation by the infusion of Fluosol. One patient exhibited a hypotensive episode during the infusion, which lasted only a short time, disappeared spontaneously, and did not prohibit the further infusion of Fluosol. We still consider that Fluosol will be clinically useful for increasing oxygen capacity and improving overall hemodynamic status as well as individual organ circulation.

Oxygen conformers in critically ill patients

In 104 patients with various pathological conditions, the correlation between oxygen consumption and oxygen delivery was analysed by the least square method. As reported by Peirce in 1977, we also found oxygen conformers among critically ill patients, but a tendency to oxygen regulator was never found in our patients.

Circulatory support with sympathetic amines in brain death

In 12 cases of brain death, the cardiovascular effects and changes of transcutaneous PO2 (PtcO2) during infusion of various sympathomimetic amines were determined. The larger amounts of vasopressors were necessary to maintain the blood pressure at more than 100 mmHg. With norepinephrine and dopamine, marked increase in blood pressure, cardiac output, systemic vascular resistance and also PtcO2 were observed. On the other hand, dobutamine was not an effective pressor agent in those situations. Even with more than 10 times the routinely used concentration of dobutamine, difficulties were encountered in keeping the blood pressure above 100 mmHg in many cases studied. With the infusion of dobutamine, a marked increase in cardiac output and heart rate were observed with a decrease in systemic vascular resistance and a fall in PtcO2 values in many occasions. In brain death, norepinephrine and dopamine will be recommended as the pressor agents in clinical practice. The changes of PtcO2 closely followed the changes of arterial blood pressure and did not parallel the changes of cardiac output or of heart rate.

P 50 in burn injury.

P50, 2,3-diphosphoglycerate (DPG), inorganic phosphorus (Pi), adenosine triphosphate (ATP), and blood gases were measured daily in 23 patients with burn injuries, until their death or discharge from the ICU. At the time of admission, P50 values were high. In nonsurvivors, P50 started to decline 1 week after the injury. Corrected P50 values to pH 7.4 were well correlated with DPG values. In survivors, P50 tended to correlated with Pi values, but in nonsurvivors at the septic or terminal stage, the values P50 did not correlate with Pi or ATP. Low P50 predicted the poor outcome of severely burned patients. At the convalescent stage of major burn injury, P50 and DPG were higher than normal and often remained elevated for weeks.

Metaraminol and dobutamine for the treatment of hypotension associated with epidural block.

In 14 patients undergoing major abdominal surgery, epidural analgesia was performed and cardiovascular changes were examined by insertion of Swan-Ganz catheters. To counteract the hypotensive episodes associated with epidural block, Dobutamine (1-3 micrograms/kg body wt min-1) and Metaraminol (0.5-1.5 micrograms/kg body wt min-1) in various doses were infused and the effects of these vasoactive agents were examined. Epidural analgesia decreased arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure and central venous pressure associated with marked decrease in cardiac index, stroke volume index, left ventricular and right ventricular stroke work without changes in systematic vascular resistance, pulmonary vascular resistance or heart rate. The infusion of Metaraminol caused a marked increase in arterial pressure, pulmonary arterial pressure, wedge pressure and central venous pressure. Calculated variables of stroke volume, systemic vascular resistance, left and right stroke work and cardiac work increased significantly. The infusion of Dobutamine caused a marked increase in arterial and pulmonary arterial pressure, wedge pressure, central venous pressure and cardiac index associated with those calculated changes of left and right stroke work and cardiac work, which were increased markedly. On the other hand, heart rate, stroke volume and pulmonary vascular resistance did not show any remarkable changes. Our study indicates that the fall in arterial blood pressure associated with epidural block may be due to marked decrease in cardiac output, and the infusion of Dobutamine is one of the desirable methods to counteract the hypotensive episode.

Cardiovascular effects of various colloidal solutions during major abdominal surgery

We examined the effects of various colloidal solutions on cardiovascular and oxygen transport variables for 26 patients undergoing gastrectomy under general anesthesia. Fluosol-DA, whole blood, 3% Dextran-40 (Saviosol), and 6% hydroxyethyl starch (hetastarch, Hespan) affected the right side of heart, but only whole blood and Fluosol-DA significantly increased cardiac output and oxygen delivery (Do2). Fluosol-DA may prove useful for critical care of hemorrhagic shock during operation or resuscitation in the immediate postoperative period.

Oxygen consumption and carbon dioxide production following open heart surgery

The VO2, VCO2 and RQ were measured in 24 patients after open heart surgery using a CO2 analyzer and O2 Consumption Calculator (Siemen Elma, Sweden). With prolonged ventilatory care, shivering was noticed in only one patient and VO2, VCO2 and RQ were rather stable and constant in patients in the Intensive Care Unit (ICU). With dopamine infusion the 3-5 kg body wt/min cardiovascular status was stable and the oxygen extraction ratio was a mean of 0.264. From those data we suggest that ventilatory support would be desirable for about 2 days for those patients in the post-operative period.

Changes of lung water and cardiovascular parameters during neurosurgical procedures associated with various types of infusion

With the Swan-Ganz catheter and double indicator technique cardiovascular parameters and lung water were measured in 16 neurosurgical procedures. Five hundred millilitres of whole blood, Manitol or Fluosol-DA, or 1000 ml of lactate-Ringer solution was infused within 30 min, and various parameters were estimated and analysed. Extravascular lung water did not change with either solutions. Fluosol-DA showed the most powerful pressure effects. With whole blood and Fluosol DA, cardiac output and oxygen availability increased. Marked hemodilution was observed with the infusion of either Manitol, Fluosol-DA or lactate-Ringer solution, but only Fluosol-DA insured adequate oxygen supply to tissues by increase in oxygen capacity in blood. Fluosol-DA proved to be one of the suitable colloidal solutions to improve the hemodynamics and hemodilution during operation.