- Email: [email protected]
Study on blood gas, acid-base balance, and metabolism during profound hypothermia by surface cooling
714
ABSTRACTS,
I5TH
rewarming, but did not recover to the precooling level even 2 hr later. (3) There were no marked changes in lung lipids in dogs which were merely maintained under ether anesthesia without cooling. These results suggest the ability of deep hypothermia to protect the lung is not plausible. Lung surfactant was influenced in hypothermia hy suppression of lipid metabolism in the lung, by alveolar hypaperfusion, and by changes in hormones relating to production or secretion of surfactant. It did not recover early after rewarming to 37°C. Consequently, administration of essential fatty acids, CDP-cholin, and corticosteroid is recommended to protect lung surfactant before operations in patients who exhibit respiratory insufficiency or malnutrition. It was essential to continue meticulous respiratory support for at least 2 hr after deep hypothermia.
100.
Changes of Vasoactice Substances during and after Simple Deep Hypothermia for OpenHeart Surgery. T. KURODA,* M. MORIMom, + K. INOKAWA,’ J, TSUCAXE,* Y. IKEDA,* H. Yozu~r~~,* AND H. SHIDA * (Second Department of Surgery, Faculty of Medicine, Shinshu University, Matsumoto 390, Japan).
The lung plays an important role in the metabolism of various vasoactive substances. In simple for open-heart surgery, the deep hypothermia metabolic role of the lung was studied in relation to lung complaints or low cardiac output syndrome (LOS) after the operation. In this present study, the plasma concentrations of dopamin+ hydroxylase (DBH), 5-hydroxytryptamine ( 5-HT), angiotensin I( AI), angiotensin II{ AII), aldosterone ( PA), and angiotensin converting enzyme activity (ACEA) were simultaneously determined during and after the hypothermia. The following results were obtained: (1) Plasma DBH and 5-HT decreased in the cooling period and gradually returned to normal in the rewamung period; thereafter these values showed no significant change. (2) In the cooling period, the ratio of AI1 formation from AI decreased, suggesting that metabolism of angiotensin in the lung decreased. (3) Plasma ACEA showed no characteristic change, suggesting little physiological significance for AH formation, From the above-mentioned results, it is concluded that the irritability of the heart is reduced during the cooling period, and the so-called serotonin-induced pulmonary injury is observed little after the operation. Moreover, homeostasis in the renin-angiotensin system is still maintained in most of the patients during hypothermia.
ANNUAL 101.
MEETING Hypothermia Prolongs Hypertensive Response of Lewodopa. P. POPOVIC, V. POPOVIC, AND Y. HARADA (Department of Physiology, Emory University Medical School, Atlanta, Georgia 30322).
It has been documented that levodapa has profound effect on cardiovascular system. Levodopa (dopamine) stimulates alpha and beta adrenergic receptors. Generally, dopamine causes a rise in blood pressure and an increase in cardiac contractile forces. In this work the effect of levodopa on arterial blood pressure in hypothermic rats was studied and compared to the effect of norepinephrine. Roth drugs were used in the amounts producing similar maximal bIood pressure increase in unanesthetized normothermic animah. Thirty-two female Sprague-Dawley rats (202 f 8 g) were used. The animals’ aortic arch was chronically cannulated (PE10) 20 days prior to experiment. Levodopa (20 mg/kg) or norepinephrine (0.1 m/kg) was dissolved in saline (0.4 ml) and administered through the cannula. Hypothermia (17.7 z 0.5”C) was induced by the hypercapnic-hypoxic cooling technique. In normothermic rats levodopa increased the mean arterial blood pressure from 120 to I60 mm Hg in 5 min. Arterial blood pressure returned to the normal value in 15 min. Norepinephrine increased the mean arterial blood pressure from 117 -+- 3 to 155 f 12 mm Hg in 1 min. The return to normal value was observed after 2-5 min. In hypothermic animals levodopa increased the arterial blood pressure from 81 f 4 to 1162 k 7 mm Hg in I5 min, and the blood pressure stayed at this level for 4 hr while norepinephrine increased the pressure from 81 * 4 to 116 z 7 min Hg in 2 to 5 min. The pressure returned to the control value after 15 to 30 min. Thus it appears that hypothermia significantly prolongs the hypertensive response to levodopa administered to the rat. One of the possibilities is that action of the enzyme dopa decarboxylase is decreased in hypothermia. These results indicate that hypothermia offers a new approach for studying levodopa action on cardiovascular system. 102.
Study on Blood Gas, Metabolism during
Acid-Base Balance, and Profmmd Hypothermia by Surface Coolittg. M. MIYAZAKI,* K. YODA,* Y. TANAKA,’ Ch. OKUDA,* AND K. OGLI * (Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyoku, Japan).
Profound hypothermia deep ether anesthesia
by surface for open-heart
cooling under ,surgery was
ABSTRACTS,
15TH
successfully carried out in order to obtain cardiac arrest for periods of over 1 hr at core temperatures below 20°C. The cocktail lytique or neuroleptics were given in divided doses as premed&&ion, and deep ether hypothermia was rapidly induced in the patient by an ice water bathing method using specially devised equipment. The method was applied to infants and children who were unable to be subjected to extracorporeal circulation. Periodical measurements were done on blood gas, acidbase balance, cortisol, HGH, and NEFA, together with the determination of blood level of ether concentration. Results were compared with the data of other types of profound hypothermia induced by N,O-0, and muscle relaxant anesthesia with rewarming by extracorporeal circulation. Rapid induction was achieved using NeO-Op-halothane and was maintained with closed ether or semi-cIosed N&-ether of 5 to 7.5% at blood levels from 148 to 286 and finally to 41 mg/dl. Maintenance of high P,Oo and hypercarbia at about 30°C have a favorabIe effect while inducing hypothermia. Catecholamines increased from normal values to 0.86 rig/ml of epinephrine and 1.86 rig/ml of norepinephrine after cardiac arrest. Elevations of blood sugar, lactate, and pyruvate were also noted. Those changes, metabolic acidosis, and a - fO1 difference, however, were milder in the ether group than in the light anesthesia with muscle relaxant group, though severe metabolic acidosis was noted in cyanotic cases. Very few transient complications such as temporary visual disturbance were noted, but satisfactorily low mortality was obtained. EEG reveals completely reversible changes.
103.
Efect of Atierial Carbon Cerebral Blood Plow thermia. Y. KAWASHIMA,* I. Ko.sucr,* K. OKMA,’
Dioxide Tension on during Deep HypoH. YOSHIKAWA,’ T. KITAGAKI,’ T. KAWAJCAMI,’ AND Y. SENOH * (Departments of Anesthesiology, The Kanto Teishin Hospital and Teikyo University School of Medicine, Second Department of Surgery, Okayama University School of Medicine, Higashigotanda, Shinagawa-ku, Tokyo 141 Japan ) .
Cerebral blood flow (CBF) is primarily regulated by arterial carbon dioxide tension in normothermia. There have been few studies, however, concerning the regulation being preserved at lower body temperatures. The study was designed to clarify the regulation of CBF by arterial Pw, during surface-induced deep hypothermia in anesthetized dogs. CBF was measured by the radioactive microspheres technique of Rudolph and
ANNUAL
MEETING
715
Haymann. The experiment consisted of two parts. In the first experiment, CBF and arterial PCO, were measured simultaneously at control (37.5”(Z), 24”C, and 18°C in nine dogs cooled by ice-water immersion under deep ether anesthesia. A linear relationship between CBF and arterial Pco, was obtained at each temperature. Increase in CBF per unit PcO, inzrement was decreased in accordance with the descent in the body temperature. In the second experiment, the PO, level was changed in three steps by adding CO, into the inspired gas after dogs were anesthetized by a large dose of morphine (5 mg/kg) and cooled to and kept at 24°C. Pw, levels obtained were 21.8, 44.8 and 68.9 mm Hg. Distribution of cardiac output to the brain in the low Pw, group was decreased to 78.1 f 15.3% of that in the normal PO, group, and increased to 125.2 k 31.8% of that in the high Pro, group. CBF per 100 g brain tissue also showed the similar changes, i.e., 78.7 k 13.0% at at high Pw2. It may low P.20, and 143 f 40.6% be concluded from these results that the regulation of CBF by arterial PCO, is preserved although the sensitivity is much decreased when compared to that in normothermia.
104.
Central Neruous System Consequences in Children of Cardiac Surgery Using Simple Deep Hypothermia and Circulatory Arrest. H. BABA, I. IWAMOTOA K. UCHIDA, K. MATSUO, SHIMA ’
Chuo Omura
N.
HIROTA,”
AND
N.
XAWA-
(Department of Surgery, Nagasaki National Hospital, 1001, Kubara-Go, 856, Japan).
This study is concerned with the influences of simple deep hypothermia on the central nervous system by means of intelligence test and electroencephalogram (EEG) before and after cardiac surgery. Method: The EEGs were recorded before and I month after surgery in 108 of a series of 134 long-term survivors (mean age of 6 years). In six of them, EEGs were also recorded continuously until the third postoperative day in order to analyze frequency and voltage. Formal psychological testing was carried out on 82 patients before and 1 month after the operation. Results: ( 1) Temporary unconsciousness was postoperatively observed in two (l-5%) of 134 patients. (2 ) In 82 patients, normal IQ was obtained postoperatively except for one patient. (3) Transitory neurologic symptoms were observed early in the postoperative period in 46 (34%) of I34 patients, but they usually disappeared 3 days after operation. (4) By analysis of a sum of voltages calculated for every wave, beta waves were most dominant immediately after the opera-
ABSTRACTS,
I5TH
rewarming, but did not recover to the precooling level even 2 hr later. (3) There were no marked changes in lung lipids in dogs which were merely maintained under ether anesthesia without cooling. These results suggest the ability of deep hypothermia to protect the lung is not plausible. Lung surfactant was influenced in hypothermia hy suppression of lipid metabolism in the lung, by alveolar hypaperfusion, and by changes in hormones relating to production or secretion of surfactant. It did not recover early after rewarming to 37°C. Consequently, administration of essential fatty acids, CDP-cholin, and corticosteroid is recommended to protect lung surfactant before operations in patients who exhibit respiratory insufficiency or malnutrition. It was essential to continue meticulous respiratory support for at least 2 hr after deep hypothermia.
100.
Changes of Vasoactice Substances during and after Simple Deep Hypothermia for OpenHeart Surgery. T. KURODA,* M. MORIMom, + K. INOKAWA,’ J, TSUCAXE,* Y. IKEDA,* H. Yozu~r~~,* AND H. SHIDA * (Second Department of Surgery, Faculty of Medicine, Shinshu University, Matsumoto 390, Japan).
The lung plays an important role in the metabolism of various vasoactive substances. In simple for open-heart surgery, the deep hypothermia metabolic role of the lung was studied in relation to lung complaints or low cardiac output syndrome (LOS) after the operation. In this present study, the plasma concentrations of dopamin+ hydroxylase (DBH), 5-hydroxytryptamine ( 5-HT), angiotensin I( AI), angiotensin II{ AII), aldosterone ( PA), and angiotensin converting enzyme activity (ACEA) were simultaneously determined during and after the hypothermia. The following results were obtained: (1) Plasma DBH and 5-HT decreased in the cooling period and gradually returned to normal in the rewamung period; thereafter these values showed no significant change. (2) In the cooling period, the ratio of AI1 formation from AI decreased, suggesting that metabolism of angiotensin in the lung decreased. (3) Plasma ACEA showed no characteristic change, suggesting little physiological significance for AH formation, From the above-mentioned results, it is concluded that the irritability of the heart is reduced during the cooling period, and the so-called serotonin-induced pulmonary injury is observed little after the operation. Moreover, homeostasis in the renin-angiotensin system is still maintained in most of the patients during hypothermia.
ANNUAL 101.
MEETING Hypothermia Prolongs Hypertensive Response of Lewodopa. P. POPOVIC, V. POPOVIC, AND Y. HARADA (Department of Physiology, Emory University Medical School, Atlanta, Georgia 30322).
It has been documented that levodapa has profound effect on cardiovascular system. Levodopa (dopamine) stimulates alpha and beta adrenergic receptors. Generally, dopamine causes a rise in blood pressure and an increase in cardiac contractile forces. In this work the effect of levodopa on arterial blood pressure in hypothermic rats was studied and compared to the effect of norepinephrine. Roth drugs were used in the amounts producing similar maximal bIood pressure increase in unanesthetized normothermic animah. Thirty-two female Sprague-Dawley rats (202 f 8 g) were used. The animals’ aortic arch was chronically cannulated (PE10) 20 days prior to experiment. Levodopa (20 mg/kg) or norepinephrine (0.1 m/kg) was dissolved in saline (0.4 ml) and administered through the cannula. Hypothermia (17.7 z 0.5”C) was induced by the hypercapnic-hypoxic cooling technique. In normothermic rats levodopa increased the mean arterial blood pressure from 120 to I60 mm Hg in 5 min. Arterial blood pressure returned to the normal value in 15 min. Norepinephrine increased the mean arterial blood pressure from 117 -+- 3 to 155 f 12 mm Hg in 1 min. The return to normal value was observed after 2-5 min. In hypothermic animals levodopa increased the arterial blood pressure from 81 f 4 to 1162 k 7 mm Hg in I5 min, and the blood pressure stayed at this level for 4 hr while norepinephrine increased the pressure from 81 * 4 to 116 z 7 min Hg in 2 to 5 min. The pressure returned to the control value after 15 to 30 min. Thus it appears that hypothermia significantly prolongs the hypertensive response to levodopa administered to the rat. One of the possibilities is that action of the enzyme dopa decarboxylase is decreased in hypothermia. These results indicate that hypothermia offers a new approach for studying levodopa action on cardiovascular system. 102.
Study on Blood Gas, Metabolism during
Acid-Base Balance, and Profmmd Hypothermia by Surface Coolittg. M. MIYAZAKI,* K. YODA,* Y. TANAKA,’ Ch. OKUDA,* AND K. OGLI * (Department of Anesthesiology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyoku, Japan).
Profound hypothermia deep ether anesthesia
by surface for open-heart
cooling under ,surgery was
ABSTRACTS,
15TH
successfully carried out in order to obtain cardiac arrest for periods of over 1 hr at core temperatures below 20°C. The cocktail lytique or neuroleptics were given in divided doses as premed&&ion, and deep ether hypothermia was rapidly induced in the patient by an ice water bathing method using specially devised equipment. The method was applied to infants and children who were unable to be subjected to extracorporeal circulation. Periodical measurements were done on blood gas, acidbase balance, cortisol, HGH, and NEFA, together with the determination of blood level of ether concentration. Results were compared with the data of other types of profound hypothermia induced by N,O-0, and muscle relaxant anesthesia with rewarming by extracorporeal circulation. Rapid induction was achieved using NeO-Op-halothane and was maintained with closed ether or semi-cIosed N&-ether of 5 to 7.5% at blood levels from 148 to 286 and finally to 41 mg/dl. Maintenance of high P,Oo and hypercarbia at about 30°C have a favorabIe effect while inducing hypothermia. Catecholamines increased from normal values to 0.86 rig/ml of epinephrine and 1.86 rig/ml of norepinephrine after cardiac arrest. Elevations of blood sugar, lactate, and pyruvate were also noted. Those changes, metabolic acidosis, and a - fO1 difference, however, were milder in the ether group than in the light anesthesia with muscle relaxant group, though severe metabolic acidosis was noted in cyanotic cases. Very few transient complications such as temporary visual disturbance were noted, but satisfactorily low mortality was obtained. EEG reveals completely reversible changes.
103.
Efect of Atierial Carbon Cerebral Blood Plow thermia. Y. KAWASHIMA,* I. Ko.sucr,* K. OKMA,’
Dioxide Tension on during Deep HypoH. YOSHIKAWA,’ T. KITAGAKI,’ T. KAWAJCAMI,’ AND Y. SENOH * (Departments of Anesthesiology, The Kanto Teishin Hospital and Teikyo University School of Medicine, Second Department of Surgery, Okayama University School of Medicine, Higashigotanda, Shinagawa-ku, Tokyo 141 Japan ) .
Cerebral blood flow (CBF) is primarily regulated by arterial carbon dioxide tension in normothermia. There have been few studies, however, concerning the regulation being preserved at lower body temperatures. The study was designed to clarify the regulation of CBF by arterial Pw, during surface-induced deep hypothermia in anesthetized dogs. CBF was measured by the radioactive microspheres technique of Rudolph and
ANNUAL
MEETING
715
Haymann. The experiment consisted of two parts. In the first experiment, CBF and arterial PCO, were measured simultaneously at control (37.5”(Z), 24”C, and 18°C in nine dogs cooled by ice-water immersion under deep ether anesthesia. A linear relationship between CBF and arterial Pco, was obtained at each temperature. Increase in CBF per unit PcO, inzrement was decreased in accordance with the descent in the body temperature. In the second experiment, the PO, level was changed in three steps by adding CO, into the inspired gas after dogs were anesthetized by a large dose of morphine (5 mg/kg) and cooled to and kept at 24°C. Pw, levels obtained were 21.8, 44.8 and 68.9 mm Hg. Distribution of cardiac output to the brain in the low Pw, group was decreased to 78.1 f 15.3% of that in the normal PO, group, and increased to 125.2 k 31.8% of that in the high Pro, group. CBF per 100 g brain tissue also showed the similar changes, i.e., 78.7 k 13.0% at at high Pw2. It may low P.20, and 143 f 40.6% be concluded from these results that the regulation of CBF by arterial PCO, is preserved although the sensitivity is much decreased when compared to that in normothermia.
104.
Central Neruous System Consequences in Children of Cardiac Surgery Using Simple Deep Hypothermia and Circulatory Arrest. H. BABA, I. IWAMOTOA K. UCHIDA, K. MATSUO, SHIMA ’
Chuo Omura
N.
HIROTA,”
AND
N.
XAWA-
(Department of Surgery, Nagasaki National Hospital, 1001, Kubara-Go, 856, Japan).
This study is concerned with the influences of simple deep hypothermia on the central nervous system by means of intelligence test and electroencephalogram (EEG) before and after cardiac surgery. Method: The EEGs were recorded before and I month after surgery in 108 of a series of 134 long-term survivors (mean age of 6 years). In six of them, EEGs were also recorded continuously until the third postoperative day in order to analyze frequency and voltage. Formal psychological testing was carried out on 82 patients before and 1 month after the operation. Results: ( 1) Temporary unconsciousness was postoperatively observed in two (l-5%) of 134 patients. (2 ) In 82 patients, normal IQ was obtained postoperatively except for one patient. (3) Transitory neurologic symptoms were observed early in the postoperative period in 46 (34%) of I34 patients, but they usually disappeared 3 days after operation. (4) By analysis of a sum of voltages calculated for every wave, beta waves were most dominant immediately after the opera-