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Physiologic variations during induced hypothermia in the dog
Research Southern
Society Abstracts Society
for Clinical
Research
ABSTRACTS OF PAPERS PRESENTED AT THE ANNUAL MEETING, NEW ORLEANS, LOUISIANA, JANUARY 29, 1955 PHYSIOLOGIC VARIATIONS DURING INDUCED HYPOTHERMIA IN THE DOG. H. M. Ausherman, W. K.
DACTIL (N-ETHYL-~ PIPERIDYL-DIPHENYL-ACETATE HYDROCHLORIDE) IN TREATMENT OF VENTRICULAR ARRHYTHMIA INDUCED BY OUABAIN.
Nowill, S. Boyarsky, H. E. Hall and W. W. Shingleton (introduced by J. V. Warren*). Dept. of Anes-
D. P. Baumann and L. D. Seager (introduced by P. L. Day*). Univ. of Arkansas School of Medi-
thesia, V. A. Hospital, Div. of Anesthesia and Urology and the Dept. of Surgery, Duke University Hospital and School of Medicine, Durham, N. C.
cine, Little Rock, Ark. Recent attempts to find an effective antifibrillary agent for use in the arrhythmia of hypothermia has led to the trial of many drugs with indifferent results. Studies with dactil@ (Lakeside Laboratories, Inc.) have suggested its applicability in this regard. Its effectiveness in the prevention of ventricular fibrillation due to benzol and epinephrine in hypothermic and normothermic dogs has been presented in a preliminary report elsewhere. As another phase of this study ventricular arrhythmia was induced by intravenous ouabain in pentobarbital anesthetized dogs. Dactil was administered in a slow, continuous intravenous drip until definite results were determined. Intermittent electrocardiographic tracings were obtained as necessary as a criterion of the status of the rhythm. Amounts of ouabain required to produce a ventricular rhythm varied considerably (0.07 to 0.395 mg./kg.). Dactil was given as a 0.5 to 1.0 per cent saline solution 10 to 50 mg. per or minute. Reversion to a supraventricular normal sinus rhythm occurred in fifteen of twenty experimental procedures completed to date. Present evidence suggests this drug may act in part by depressing ventricular irritability.
Recent enthusiasm for the use of induced hypothermia for cardiac surgery and the hibernation technic for severe infection and other shock-like states prompted the authors to familiarize themselves with the technics and physiologic variations of induced hypothermia in the dog. Hypothermia was produced most rapidly and efficiently by emersion in ice water under pentothal@ or nembutal@ sodium anesthesia. Biologic functions tested were as follows: blood pressure, pulse rate and electrocardiographic changes, respiratory rate, tidal and minute volume, oxygen consumption, electroencephalographic patterns, serum potassium and sodium, arterial pH, carbon dioxide tension, per cent oxygen saturation, hematocrit, renal and hepatic functions. Respiratory rate, minute volume and oxygen consumption are markedly depressed. Arterial carbon dioxide pressure and pH vary toward respiratory alkalosis. Arterial blood remains well oxygenated until respiration is nearly absent. Serum sodium was essentially unchanged but serum potassium was decreased. Blood pressure and pulse rate declined progressively with the decrease in rectal temperature. Electrocardiographic changes were those associated with a sinus bradycardia and alkalosis. Hypothermia in the dog appears to be a relatively safe procedure at body temperatures at or above 25’~. and for less than twelve hours. Temperatures below 25”~. and for more than twelve hours have a progressively higher mortality.
SERUM LIPID FRACTIONS IN INDUCED AND SPONTANEOUS HYPOTHYROIDISM; MODIFICATION BY BETA-SITOSTEROL. M. M. Best,* C. H. Duncan, J. D. Wathen and H. D. Kerman. * Inst. of Medical Research, Univ. of Louisville School of Medicine, Louisville, Ky. Serum lipid fractions were followed in a group of patients with congestive failure rendered hypothyroid by I-131. Four patients with rheumatic mitral stenosis had initially
* Asterisks indicate members. JULY,
1955
13
Society Abstracts Society
for Clinical
Research
ABSTRACTS OF PAPERS PRESENTED AT THE ANNUAL MEETING, NEW ORLEANS, LOUISIANA, JANUARY 29, 1955 PHYSIOLOGIC VARIATIONS DURING INDUCED HYPOTHERMIA IN THE DOG. H. M. Ausherman, W. K.
DACTIL (N-ETHYL-~ PIPERIDYL-DIPHENYL-ACETATE HYDROCHLORIDE) IN TREATMENT OF VENTRICULAR ARRHYTHMIA INDUCED BY OUABAIN.
Nowill, S. Boyarsky, H. E. Hall and W. W. Shingleton (introduced by J. V. Warren*). Dept. of Anes-
D. P. Baumann and L. D. Seager (introduced by P. L. Day*). Univ. of Arkansas School of Medi-
thesia, V. A. Hospital, Div. of Anesthesia and Urology and the Dept. of Surgery, Duke University Hospital and School of Medicine, Durham, N. C.
cine, Little Rock, Ark. Recent attempts to find an effective antifibrillary agent for use in the arrhythmia of hypothermia has led to the trial of many drugs with indifferent results. Studies with dactil@ (Lakeside Laboratories, Inc.) have suggested its applicability in this regard. Its effectiveness in the prevention of ventricular fibrillation due to benzol and epinephrine in hypothermic and normothermic dogs has been presented in a preliminary report elsewhere. As another phase of this study ventricular arrhythmia was induced by intravenous ouabain in pentobarbital anesthetized dogs. Dactil was administered in a slow, continuous intravenous drip until definite results were determined. Intermittent electrocardiographic tracings were obtained as necessary as a criterion of the status of the rhythm. Amounts of ouabain required to produce a ventricular rhythm varied considerably (0.07 to 0.395 mg./kg.). Dactil was given as a 0.5 to 1.0 per cent saline solution 10 to 50 mg. per or minute. Reversion to a supraventricular normal sinus rhythm occurred in fifteen of twenty experimental procedures completed to date. Present evidence suggests this drug may act in part by depressing ventricular irritability.
Recent enthusiasm for the use of induced hypothermia for cardiac surgery and the hibernation technic for severe infection and other shock-like states prompted the authors to familiarize themselves with the technics and physiologic variations of induced hypothermia in the dog. Hypothermia was produced most rapidly and efficiently by emersion in ice water under pentothal@ or nembutal@ sodium anesthesia. Biologic functions tested were as follows: blood pressure, pulse rate and electrocardiographic changes, respiratory rate, tidal and minute volume, oxygen consumption, electroencephalographic patterns, serum potassium and sodium, arterial pH, carbon dioxide tension, per cent oxygen saturation, hematocrit, renal and hepatic functions. Respiratory rate, minute volume and oxygen consumption are markedly depressed. Arterial carbon dioxide pressure and pH vary toward respiratory alkalosis. Arterial blood remains well oxygenated until respiration is nearly absent. Serum sodium was essentially unchanged but serum potassium was decreased. Blood pressure and pulse rate declined progressively with the decrease in rectal temperature. Electrocardiographic changes were those associated with a sinus bradycardia and alkalosis. Hypothermia in the dog appears to be a relatively safe procedure at body temperatures at or above 25’~. and for less than twelve hours. Temperatures below 25”~. and for more than twelve hours have a progressively higher mortality.
SERUM LIPID FRACTIONS IN INDUCED AND SPONTANEOUS HYPOTHYROIDISM; MODIFICATION BY BETA-SITOSTEROL. M. M. Best,* C. H. Duncan, J. D. Wathen and H. D. Kerman. * Inst. of Medical Research, Univ. of Louisville School of Medicine, Louisville, Ky. Serum lipid fractions were followed in a group of patients with congestive failure rendered hypothyroid by I-131. Four patients with rheumatic mitral stenosis had initially
* Asterisks indicate members. JULY,
1955
13