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Biomedical subjects

H Tokioka

Publications and source records attributed to H Tokioka.

29 records · Page 2Linked to original sources
PubMed1990

Efficacy of flow-by during continuous positive airway pressure ventilation.

We investigated clinically the differences in respiratory work of patients imposed by three modes of one ventilator: the flow-by system, the demand valve system, and the pressure support system. Inspiratory work using flow-by and pressure support systems was reduced sufficiently when compared to the demand valve system. Moreover, fluctuation of the airway pressure was minimal with the flow-by mode. These results suggest that the flow-by mode is beneficial to patients breathing spontaneously with continuous positive airway pressure.

Aged↗
PubMed1990

[The effect of pressure support ventilation on breathing patterns and the work of breathing].

We assessed breathing patterns during pressure support ventilation (PSV) and its relationship with the work of breathing in 10 postoperative patients. With increasing levels of pressure support, minute ventilation and tidal volume increased with a decrease in respiratory frequency. Increased minute ventilation was achieved by increased mean inspiratory flow. Duty cycle, however, decreased with PSV. This decrease might allow the diaphragm a longer rest period between contractions, which might decrease the risk of diaphragmatic fatigue. Furthermore, PSV reduced the inspiratory work added by a ventilator to near zero. Oxygen consumption was also decreased with PSV. We conclude that PSV improved the breathing patterns and minimized the work of breathing spontaneously via a ventilator.

Adult↗
PubMed1989

Comparison of pressure support ventilation and assist control ventilation in patients with acute respiratory failure.

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on the breathing pattern, work of breathing and blood gas exchange in 8 patients with acute respiratory failure. During ACV, the tidal volume was set at 10 ml/kg, and the inspiratory flow was set at 50 to 70 l/min. During PSV, the pressure support level selected was 27 +/- 5 cm H2O to make the breathing pattern regular. Tidal volume was significantly higher (908 +/- 179 ml vs. 633 +/- 96 ml) during PSV than during ACV at a lower peak airway pressure. Respiratory frequency was lower (15 +/- 4 breaths/min vs. 24 +/- 5 breaths/min) during PSV than during ACV, associated with a lower duty cycle, which improved synchrony between the patient and the ventilator. The oxygen cost of breathing, an estimate based on the inspiratory work added by a ventilator and the oxygen consumption, did not change significantly. PaO2 was significantly higher during PSV than during ACV. We conclude that PSV using high levels of pressure support can improve the breathing pattern and oxygenation and fully sustain the patient's ventilation while matching his inspiratory efforts.

Adult↗
PubMed1989

Effect of pressure support ventilation on breathing patterns and respiratory work.

We assessed the effect of pressure support ventilation (PSV) on breathing patterns and the work of breathing in 10 postoperative patients. Minute ventilation (VE) increased by 8% with 5 cm H2O PSV and 10% with 10 cm H2O PSV compared to 0 cm H2O PSV. The increase in VE was achieved by increased mean inspiratory flow (24% with 5 cm H2O PSV and 67% with 10 cm H2O PSV) and a decrease in duty cycle (13% with 5 cm H2O PSV and 39% with 10 cm H2O PSV). The decrease in duty cycle along with a decrease in respiratory frequency allowed a greater expiratory time including a rest period for the respiratory muscles, which might minimize the risk of muscle fatigue. Furthermore, the inspiratory work added by the ventilator was near zero with 5 cm H2O PSV and 10 cm H2O PSV. Oxygen consumption also decreased significantly with 5 cm H2O PSV. We conclude that PSV improves the breathing patterns and minimizes the work of breathing spontaneously via a ventilator.

Adult↗
PubMed1988

Use of diltiazem to control circulatory fluctuations during resection of a phaeochromocytoma.

This report describes the use of diltiazem to control circulatory fluctuations during anaesthesia in five patients undergoing resection of a phaeochromocytoma. Diltiazem was administered continuously i.v. before anaesthesia and during surgery until the draining vein from the tumour had been ligated. Arterial pressure and systemic vascular resistance decreased in association with the infusion of diltiazem. Heart rate was stable, and there was no ventricular tachyarrhythmia. Arterial pressure was controlled easily during the manipulation of the tumour, and there were no hypotensive episodes after the removal of the tumour.

Adrenal Gland Neoplasms↗
PubMed1987

Effects of intracoronary infusion of arterial blood or Fluosol-DA 20% on regional myocardial metabolism and function during brief coronary artery occlusions.

Effects of intracoronary infusion (50 ml/min) of arterial blood, oxygenated or unoxygenated Fluosol, or Plasmalyte A on hemodynamics, electrocardiogram, regional myocardial function, and lactate metabolism were studied in six closed-chest dogs during 2 min occlusions of the left anterior descending coronary artery followed by 10 min of reperfusion. Normal hemodynamics were maintained with infusion of arterial blood and oxygenated Fluosol, whereas unoxygenated Fluosol and Plasmalyte A resulted in hemodynamic deterioration similar to that noted with no treatment. Ischemic zone systolic fractional area change, an index of systolic function measured by two-dimensional echocardiography, remained normal during the occlusion supplemented with intracoronary arterial blood (49 +/- 7%), was moderately hypokinetic with oxygenated Fluosol (31 +/- 10%), and became severely hypokinetic with unoxygenated Fluosol (14 +/- 14%), with Plasmalyte A (2 +/- 13%), and in the absence of treatment (5 +/- 9%). Only infusion of arterial blood resulted in no ST segment elevation or lactate production. Thus intracoronary infusion of arterial blood during brief coronary occlusion maintained normal myocardial function and aerobic metabolism. Infusion of oxygenated Fluosol resulted in amelioration of the decline in regional function after coronary occlusion, but not complete protection.

Angioplasty, Balloon↗
PubMed1985

The acute effects of prostaglandin E1 on the pulmonary circulation and oxygen delivery in patients with the adult respiratory distress syndrome.

Prostaglandin E1 was administered intravenously to 10 patients who had the adult respiratory distress syndrome associated with severe infection in order to investigate its hemodynamic effects. Infusion of PGE1 significantly decreased the mean pulmonary arterial pressure, mean systemic arterial pressure, pulmonary vascular resistance and systemic vascular resistance, and increased the cardiac index, oxygen delivery and oxygen consumption. No significant difference was noted in the intrapulmonary shunt fraction. These results indicate that administration of PGE1 improves pulmonary hemodynamics and tissue oxygenation in patients with acute respiratory distress syndrome, by reducing right ventricular afterload and increasing the cardiac index.

Aged↗
PubMedDate not supplied

Experimental evaluation of a new transducer tipped catheter.

The accuracy and fidelity of a new transducer-tipped catheter (Camino Laboratories) was compared in 10 closed chest anesthetized dogs with standard Millar catheters. Simultaneous Camino and Millar measurements of left ventricular pressures and its first derivative (dp/dt) were recorded in control, after Isoprenaline infusion and during left anterior descending coronary artery balloon occlusion, to vary the pressures for comparison. Linear regression analysis comparing the Camino and Millar systems yielded a good correlation, and one way analysis of variance showed no difference between the two catheter readings, thus revealing that the recently developed Camino disposable transducer-tipped catheter provides accurate measurements of left ventricular pressure and its first derivative.

Animals↗