Search PubMed⌕ Search

Biomedical subjects

M Takaori

Publications and source records attributed to M Takaori.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Effect of superimposed high frequency oscillation on pulmonary edema induced by intrapulmonary injection of hydrochloric acid in dogs].

Effect of superimposed high frequency oscillatory ventilation on pulmonary gas exchange was investigated in seven anesthetized and paralyzed dogs with pulmonary edema induced by intrapulmonary injection of hydrochloric acid. Efficacy of the ventilatory modes (HFO:6 Hz and 12 Hz) was evaluated observing changes in ventilation-perfusion mismatch, which was demonstrated by using six inert gas elimination method. The ventilation with 6 Hz HFO had no significant effect on PaO2, true shunt, and perfusion distribution. With 12 Hz HFO, PaO2 showed a tendency to increase from 57 +/- 18 mmHg at IPPV to 144 +/- 117 mmHg (0.05 less than P less than .01), and the true shunt decreased from 42.2 +/- 29.0% at IPPV to 16.6 +/- 25.8% (P less than 0.05). However, no change appeared in the perfusion distribution. During the ventilation with 12 Hz HFO increased mean airway pressure produces a PEEP-like effect, which may improve the pulmonary gas exchange by opening small airways, namely a decrease in the true shunt rather than an improvement in the ventilation-perfusion maldistribution.

Animals↗
PubMed1991

[Hepatic circulation and anesthesia].

Hepatic artery blood flow changes to buffer portal blood flow alterations, maintaining a constant total hepatic blood flow. Portal blood flow is regulated by preportal organs, such as intestine, pancreas and spleen. The liver plays an important role as a blood reservoir for cardiovascular homeostasis. Hepatic blood volume is mobilized actively to the systemic circulation by sympathetic stimulation. Sinusoid, the specialized capillary of the liver, and Disse's space are separated by endothelial cells, which have numerous fenestrations, allowing effective exchanges of solutes between hepatocytes and blood. Unidirectional blood flow in the acinus causes functional differences of hepatocytes according to the lobular zones. Although the majority of anesthetics decreases liver blood flow in a dose dependent manner, halothane inhibits hepatic arterial buffer response, while isoflurane and narcotics preserve it. Energy depletion, cellular acidosis, alteration of calcium homeostasis and superoxide-induced membrane damage, are all implicated as important factors for ischemia-induced liver injury. A better understanding of ischemia-induced derangements of cell function will lead to more rational preservation of the liver cells in the future.

Anesthetics↗
PubMed1991

[Intraoperative fluid therapy by lactated Ringer's solution with various concentrations of potassium].

Lactated Ringer's solutions, whose concentration of potassium was 10 or 20 mEq.l-1, were infused into 10 and 9 patients undergoing surgical operations under general anesthesia, respectively. Effects of these fluid therapies on serum potassium and blood sugar were studied comparing with the effect of infusion of regular lactated Ringer's solution. A decrease in serum potassium concentration seen with the regular lactated Ringer's solution during the surgery was minimized with the lactated Ringer's solutions of 10 or 20 mEq.l-1 of potassium. With the lactated Ringer's solutions of higher concentrations of potassium, an increase in blood sugar level, which was noted with the regular lactated Ringer's solution, was not observed although all the lactated Ringer's solutions contained 0.7% of glucose. Furthermore, base excess remained at a normal level in patients of high potassium groups, but it decreased in patients of the regular potassium group. Lactated Ringer's solutions of high potassium levels are useful to maintain serum potassium and glucose levels at more normal levels during surgical procedures under general anesthesia.

Adult↗
PubMed1991

[A simple expression of the intrapulmonary ventilation-perfusion ratio distribution curves].

We propose a method to express the intrapulmonary ventilation-perfusion distribution curves obtained by 6 inert gas elimination technique. A VA/Q distribution curve was obtained by calculating the amount of perfusion distributed in each fraction of the VA/Q as percentage of the cardiac output and then averaging them to obtain a single distribution curve. By this method, it is possible to simplify the representation of the distribution curve, to clarify the serial changes through the experiment, and further to compare different patterns in several experimental groups.

Humans↗
PubMed1990

Effect of hemodilution on capillary and arteriolovenous shunt flow in organs after cardiac arrest in dogs.

The purpose of this study was to observe the changes in capillary and arteriolovenous shunting blood flow after cardiac arrest and subsequent resuscitation by venous return occlusion produced by inflation of an intra-atrial balloon and cross-clamping of the ascending aorta, and to determine how hemodilution might modify such changes. Organ capillary blood flow and the fractional distribution of cardiac output were measured by the microsphere (9-microns diameter) trapping method in dogs. Simultaneously, the arteriolovenous shunt rate was measured by continuous collection of venous blood drained at 4.8 ml.min-1 for 2 min from the brain, kidney, liver, splanchnic organs, skeletal muscle of the pelvic limb, and all of the systemic circulatory organs. The capillary blood flow of the brain, thyroid gland, pancreas, and stomach decreased after circulatory arrest in five nonhemodiluted dogs (group C); arteriolovenous shunt rate was unchanged after circulatory arrest in this group. However, with hemodilution, which was induced either before (pre group, n = 5) or after (post group, n = 5) circulatory arrest, no change occurred in the shunt rate in any of the organs, with the exception of an increase in the systemic arteriolovenous shunt rate in the pre group. Capillary blood flow was maintained at almost the same level as before circulatory arrest in the pre group, but increased significantly in several organs of the post group. The data indicated that hemodilution might be effective for prevention of organ ischemia after cardiac arrest.

Animals↗
PubMed1990

[Measurement of airway resistance by an interrupter technique in anesthetized dogs during methacholine induced bronchoconstriction].

Airway resistance was measured by an interrupter technique in anesthetized and paralyzed dogs. Bronchoconstriction was then induced by the inhalation of methacholine hydrochloride at a concentration of 25 or 50 mg . ml-1 for ten minutes. Airway resistance was measured again immediately after the inhalation of methacholine and 50 minutes later. Under normal conditions, airway resistance increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K1 + K2X. K1 and K2 were calculated by a least square method. As a result, K1 increased markedly immediately after the inhalation of methacholine and returned to the control level thereafter. However, it was still higher than the control 50 minutes later. On the other hand, no statistically significant changes were observed because the changes in K2 were variable. In some cases, K2 increased, while in others it was unchanged. K2 decreased in more cases, however, and a negative value was often seen. This inverse correlation between flow and resistance was supposed to reflect the occurrence of small airway obstructions during the end expiratory phase. Therefore, it was considered that this method is capable of detecting small airway abnormalities which could not be detected by %FEV1.0.

Airway Resistance↗
PubMed1989

Effects of alveolar hypoxia on pulmonary capillary beds.

Using open chested dogs (n = 12), we tested the hypothesis that the pulmonary capillary changes its caliber in response to alveolar hypoxia. Animals were placed in a left upright lateral position. Pulmonary perfusion was measured by electromagnetic flow transducers attached to the main and left pulmonary arteries. Systemic artery, pulmonary artery and pulmonary vein pressures were measured via catheters inserted into them. Shunt flow through the pulmonary capillary beds was evaluated by the microsphere method, injecting a mixture of three different size (3, 9 and 15 microm) radioactive microspheres into the inferior vena cava. Right one lung ventilation with left lung atelectasis or left lung insufflation of 5 cmH2O (O2 or He) was achieved by occluding the left main bronchus with a blocker attached to an endotracheal tube. Right one lung ventilation caused redistribution of the perfusion from the left lung to the right lung. Left pulmonary vascular resistance increased significantly, while total pulmonary vascular resistance showed no significant changes. The shunt ratios of the 3 and 9 microm microspheres were not changed by right one lung ventilations with left lung atelectasis or insufflation. The shunt ratio of the 3 microm microspheres through the left lung was significantly higher than that through two lungs during both the two lung and one lung ventilations. We concluded that caliber changes in the pulmonary capillary do not occur in response to alveolar hypoxia.

Journal Article↗
PubMed1989

Effects of hypocapnia and hypercapnia on splanchnic circulation and hepatic function in the beagle.

The effects of mild hypocapnia (PaCO2 22 mm Hg) and hypercapnia (PaCO2 59 mm Hg) on the splanchnic circulation and hepatic function were studied in six pentobarbital anesthetized, laparotomized, mechanically ventilated beagles. Tidal volume and respiratory frequency were held constant throughout the measurements. Hepatic artery blood flow (HABF) and portal vein blood flow (PVBF) were measured by electromagnetic flowmeters. Hepatic function was assessed by indocyanine green (ICG) elimination kinetic analysis after intravenous injection of the dye. Hypocapnia caused a decrease in HABF without affecting the systemic circulation. Hypercapnia, on the other hand, caused a significant increase in cardiac output without changing mean arterial pressure. There was a significant increase in PVBF and total hepatic blood flow (THBF = PVBF + HABF). Despite the increases in PVBF and THBF, the half-life of ICG was significantly longer during hypercapnia (9.09 +/- 0.79 min) than during hypocapnia (7.16 +/- 0.37 min), and plasma ICG clearance was smaller during hypercapnia (4.79 +/- 0.44 ml.min-1) than during hypocapnia (5.44 +/- 0.33 ml.min-1) or normocapnia (5.27 +/- 0.50 ml.min-1), indicating the depressed hepatic function during hypercapnia. We conclude that mild hypocapnia decreases HABF without affecting hepatic function and that mild hypercapnia is associated with a depression of hepatic function in spite of the increases in PVBF and THBF.

Animals↗
PubMed1989

[The effect of IPPV, with or without PEEP, on central venous pressure].

Changes in central venous pressure (CVP) during intermittent positive pressure ventilation with a Bennett 7200 respirator were measured in 30 postoperative patients without hemodynamic abnormalities. The tidal volume was changed from 300 ml to 900 ml and the PEEP was changed from 0 cmH2O to 8 cmH2O, step by step, respectively. Mean airway pressure (Pmean), maximal airway pressure (Pmax), arterial blood pressure, and heart rate were measured simultaneously with the measurement of CVP. CVP increased linearly with increases in the tidal volume and PEEP. A linear correlation was seen between Pmean and CVP. The value of A was 7.5 +/- 6.2 cmH2O and that of B was 0.32 +/- 0.13 when the equation of the regression line was Y = A + BX, where X was Pmean and Y was CVP. The coefficient of correlation was 0.88 +/- 0.09 (n = 30, P less than 0.01). The value of CVP during intermittent positive pressure ventilation increased linearly at rate which was 32% of the increase in Pmean. The value of CVP was considered to be 7.5 +/- 6.2 cmH2O when Pmean was zero. There was no change in the arterial blood pressure and heart rate throughout the measurement. This suggests that increases in CVP might not reflect any accompanying hemodynamic change.

Central Venous Pressure↗
PubMed1989

[The effect of hemodilution on capillary blood flow and arteriovenous shunt after resuscitation in dogs].

The present study was designed to elucidate the adverse effects of temporary circulatory arrest upon the capillary blood flow and arteriovenous shunt and additionally to observe how hemodilution may improve such microcirculatory deterioration. The organ capillary blood flow and organ fraction of cardiac output were measured by the microsphere (phi 9 microns) trapping method in 14 organs. Simultaneously, the arteriovenous shunt rate was measured by continuous collection of drained venous blood at 4.8 ml.min-1 for two minutes from the brain, kidney, liver, splanchnic organs, skeletal muscle of the pelvic limb and all systemic circulatory organs. In five non-hemodiluted dogs (C group), the capillary blood flows decreased in the thyroid gland and pancreas at 30 minutes after circulatory arrest, and in these organs as well as in the brain and stomach at 90 minutes after the arrest. Change in the fraction of cardiac output was similar to that in the capillary blood flow. The arteriovenous shunt rate was unchanged after circulatory arrest. The remaining ten dogs were hemodiluted with dextran-70 solution either before (Pre group, five dogs) or after (Post group, five dogs) circulatory arrest. Both groups of hemodilution maintained the capillary blood flow and showed no alteration of the arteriovenous shunt rate after circulatory arrest, except for an increase in the systemic arteriovenous shunt rate in the Pre group. These results suggest that hemodilution maintains the capillary blood flow at a normal level and ameliorates the oxygen supply into organs after circulatory arrest.

Animals↗
PubMed1989

[Dose dependent effects of dichloroacetate on lactic acidosis in dogs].

Dose dependent effects of DCA (dichloroacetate) on lactic acidosis were studied in 30 mongrel dogs under pentobarbital anesthesia. Lactic acidosis was induced by infusion of either lactate (n = 15) or pyruvate (n = 15) for 20 min. In each dog, saline or DCA (100 mg.kg-1 or 300 mg.kg-1) was given for ten min iv. at ten min after the beginning of lactate or pyruvate infusions. Reduction in serum pyruvate levels was more prominent than that in lactate levels in both the lactate and pyruvate infusion groups. DCA in a dose of 100 mg.kg-1 was more effective to reduce serum pyruvate levels and arterial pH than 300 mg.kg-1 of DCA. There were no differences between saline and DCA (100 mg.kg-1 or 300 mg.kg-1) administrations in mean arterial pressure and cardiac index. This study confirmed the hypothesis that DCA reduces serum lactate levels via acceleration of pyruvate metabolism. It was concluded that the ability of DCA to reduce serum lactate levels is dose-dependent and a large dose of DCA (300 mg.kg-1) would not be necessary for lactic acidosis.

Acetates↗
PubMed1988

Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K1 values.

The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflations decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K(1) + K(2)X. K(1), calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K(2) value of the endotracheal tube used in this study (Portex((R)) I.D. 8 mm, length 26 cm) was quite high (5.0 cmH(2)O.1(-2).sec(2)), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K(1) measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.

Journal Article↗