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Biomedical subjects

D M Philbin

Publications and source records attributed to D M Philbin.

81 records · Page 5Linked to original sources

Hemodynamic consequences of the combination of isoflurane anesthesia (1 MAC) and beta-adrenergic blockade in the dog.

The hemodynamic response to the combination of isoflurane (1 MAC) and propranolol (0.5 mg/kg) was studied in 12 intact ventilated dogs following basal anesthesia with chloralose-urethane. When propranolol was administered during isoflurane anesthesia, stroke volume was maintained with a higher pulmonary capillary wedge pressure (3.2 plus or minus 0.7 mm Hg to 6.3 plus or minus 1.4 mm Hg), while systemic vascular resistance remained unchanged. When isoflurane was administered to the previously beta-adrenergically blocked dog, there were declines in systemic pressure and cardiac output (P smaller than 0.01) and in pulmonary arterial pressure and stroke volume (P smaller then 0.05), without change in systemic vascular resistance. When isoflurane was subsequently discontinued, these changes were reversed, and in addition, systemic vascular resistance increased (P smaller than 0.05). These data indicate that isoflurane has pharmacologic properties compatible with a peripheral beta-adrenergic stimulating action.

Anesthesia↗

Effects of diltiazem on renin-aldosterone and ACTH-adrenocortical function during upper abdominal surgery.

STUDY OBJECTIVE: To observe the effects of continuous intravenous infusion of diltiazem on the renin-aldosterone system and ACTH-adrenocortical axis responses during surgical stimulation. DESIGN: Randomized study of intravenous diltiazem. SETTING: Operating room at the Hyogo Medical College Hospital. PATIENTS: Twenty-three patients undergoing upper abdominal surgery were divided into two groups: the control group (n = 10) and the diltiazem group (n = 13). All the patients were without any complications and classified as ASA physical status I. INTERVENTIONS: Patients in the diltiazem group received an infusion of 10 micrograms/kg/min for 90 to 120 minutes following skin incision. MEASUREMENTS AND MAIN RESULTS: Plasma adrenocorticotropic hormone, plasma aldosterone and cortisol concentrations, and plasma renin activity were determined with radioimmunoassay before the induction of anesthesia at 10, 30, 60, and 90 minutes after skin incision and at the end of anesthesia. Renin activity did not change significantly. Maximal increases in plasma adrenocorticotropic hormone, aldosterone, and cortisol observed 90 minutes after skin incision were 355 +/- 95 pg/ml, 118 +/- 30 pg/ml, and 14.2 +/- 2.3 micrograms/dl in the control group versus 246 +/- 41 pg/ml, 119 +/- 25 pg/ml, and 15.0 +/- 1.8 micrograms/dl in the diltiazem group, respectively, and there were no significant differences between these groups. Adrenocorticotropic hormone was significantly lower in the diltiazem group compared with that in the control group 60 minutes after the start of surgery (p less than 0.05). There was marked natriuresis (40 +/- 25 microEq/min vs 470 +/- 147 microEq/min at the 90-minute mark) and diuresis (0.16 +/- 0.13 ml/min vs 2.53 +/- 0.88 ml/min) in the diltiazem group. CONCLUSIONS: Diltiazem at this dose increased urine output and sodium excretion without affecting most of these hormonal responses to surgical stimulation. These findings suggest that diltiazem has beneficial renal effects independent of hormonal concentrations.

Abdomen↗

Hemodynamic effects of metocurine in patients with coronary artery disease receiving propranolol.

This study was undertaken to determine the circulatory effects of metocurine (dimethyltubocurarine) in 7 men scheduled for coronary artery surgery who had been receiving propranolol for at least 6 weeks before morphine-N2O-O2 anesthesia. The study was divided into 4 measurement periods: (1) control after induction; (2) 5 minutes after administration of 0.35 mg/kg of metocurine; (3) 10 minutes after; (4) 20 minutes after. There were no significant changes in mean blood pressure, heart rate (HR) central venous pressure or arterial blood gases throughout the study. Cardiac index rose significantly from a control value of 1.89 +/- 0.1 L/min/m2 to 2.39 +/- 0.2 L/min/m2 in period 2 and remained elevated throughout (2.53 +/- 0.3 and 2.33 +/- 0.2 Lmin/m2). Systemic vascular resistance (SVR) fell from a control value of 20.2 +/- 1.8 units to 16.1 +/- 1.6 units in period 2 and remained below control in periods 3 and 4 (17.2 +/- 1.8 and 16.9 +/- 1.3). These data suggest that metocurine produced a significant decrease in SVR in the presence of propranolol, resulting in an increase in cardiac output (and stroke volume) in a compensated heart, to maintain perfusion pressure. The possibility of a central (cardiac) effect cannot be excluded, but the lack of an increase in HR suggests it would not be clinically significant.

Adult↗