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Biomedical subjects

J Takezawa

Publications and source records attributed to J Takezawa.

At least 55 records · Page 3Linked to original sources
PubMed1989

High-frequency oscillation for persistent fetal circulation after repair of congenital diaphragmatic hernia.

A female neonate who had been diagnosed as having congenital diaphragmatic hernia by ultrasonography was delivered by cesarean section. After the hernia was repaired, she developed hypoxemia and hypercapnia, probably due to persistent fetal circulation (PFC). Neither conventional mechanical ventilation (CMV) nor manual ventilation improved the respiratory status. High-frequency oscillation (HFO) successfully improved pulmonary gas exchange, but we failed to wean the patient from HFO by using intermittent HFO. The patient was again placed on CMV for weaning and was extubated on the 12th ICU day. We conclude that HFO can be an alternative respiratory modality in patients with respiratory failure due to PFC after the repair of congenital diaphragmatic hernia.

Female↗
PubMed1989

Effects of norepinephrine on renal function in septic patients with normal and elevated serum lactate levels.

Effects of iv norepinephrine (NE) on renal function were investigated retrospectively in 15 patients with hyperdynamic septic shock. All patients had either a low systolic BP less than 80 mm Hg, and/or oliguria less than 0.5 ml/kg-h. We examined their serum creatinine level (SCr), daily urine flow (UF), 24-h creatinine clearance (Ccr), and hemodynamic indices before and during NE infusion. Before NE administration, the patients were divided into those with with a serum lactate level (Lac) less than 20 mg/dl (group A, n = 9) and greater than 20 mg/dl (group B, n = 6). NE was infused continuously at rates between 0.05 and 0.24 microgram/kg.min which increased systolic BP by greater than or equal to 20 mm Hg. Cardiac index was not significantly changed in either group. In group A, NE increased both UF (p less than .05), and systemic vascular resistance index (SVRI) (p less than .01), but did not affect Ccr. In group B, NE did not increase UF nor SVRI, and decreased Ccr significantly (p less than .05). It is concluded that NE increased UF and SVRI only when Lac was in normal range; otherwise, NE reduced renal function. Thus, when administering NE to increase UF, both Lac and renal function should be monitored carefully.

Adult↗
PubMed1989

Prediction of arterial oxygen partial pressure from intrapulmonary venous admixture.

A short program was developed to predict the PaO2 at a given FIO2 by using arterial and mixed venous blood gas data obtained at an FIO2 of 1.0. Our program resolves Adair's equation and the shunt equation inversely, on the assumption that intrapulmonary venous admixture and the arteriovenous oxygen content difference remain constant during the study. The study was conducted on 19 patients with respiratory failure who were intubated and mechanically ventilated. According to linear regression analysis, regression coefficients of 0.91 and 0.97 were obtained between the measured PaO2 values and those estimated by the arterial/alveolar oxygen tension ratio (PaO2/PaO2) and our program, respectively (n = 23). The PaO2 values were predicted more accurately by our program than those calculated by PaO2/PaO2. Because our program is simple enough to be carried out with a pocket computer, it may be helpful in a bedside decision of lowering FIO2, especially in patients who require a high FIO2 level to maintain sufficient arterial oxygenation.

Blood Gas Analysis↗
PubMed1989

Jet flow-regulated expiratory resistance to maintain constant CPAP during the entire respiratory phase.

We have developed a new continuous positive airway pressure (CPAP) device that consists of a microcomputer, a pressure transducer, and a pair of electronic interface valves. One of these valves creates the inspiratory demand flow, and the other creates the opposing jet flow by acting as an expiratory valve to maintain a constant CPAP. By controlling the two electronic interface valves, the airway pressure can be kept constant during the entire respiratory cycle. We compared our device with CPAP systems supplied with commercially available ventilators: the Puritan-Bennett 7200a, the Bear 5, the Servo 900C, and the CV 2000. A two-chambered spring loaded model lung was used to simulate inspiration and a piston pump model lung to simulate active exhalation. We compared both the inspiratory triggering work (WWIt) and expiratory flow-resistive work (WE) of each ventilator while in CPAP mode by calculating the corresponding areas of the pressure-volume loops using electrical integration. The WWIt of our apparatus and demand-flow ventilators was much smaller than that of the CV 2000. In our device, WE was also much smaller than those of the others. These results indicate that our device can be used for CPAP without causing airway pressure fluctuation, and therefore, without imposing an extra workload on the patient.

Humans↗
PubMed1989

Gravity-dependent atelectasis. Radiologic, physiologic and pathologic correlation in rabbits on high-frequency oscillation ventilation.

The authors identify the radiologic features of progressive atelectasis induced under conditions of reduced lung volume. Control (n = 5) and experimental (n = 7) animals were placed on high-frequency oscillation (HFO) ventilation (mean airway pressure: 3 cm H2O) for 6 hours. In the experimental animals, lung volume was artificially reduced by pneumoperitoneum during HFO ventilation. Computed tomography scans and chest radiographs were obtained every hour, and arterial blood gases analyzed. No changes were detected in the control animals. In the experimental animals, in which hypoxemia developed, homogeneous opacity in the dependent lung was found on CT images, and chest radiographs showed a diffuse homogenous shadow with loss of lung volume. Study of pathologic sections from the lung showed that the roentgenographic findings represented atelectasis. The lung was divided into three zones, from dependent to nondependent regions: severe atelectasis, mild atelectasis, and normal lung. Hyperinflations eliminated atelectasis seen on the CT images and alleviated hypoxemia; however an undesirable effect that causes barotrauma also was observed.

Animals↗
PubMed1989

[Quantitative comparison of ventilator-induced work during simulated CPAP in eight demand-flow valve ventilators].

The ventilator-induced work during continuous positive airway pressure (CPAP) mode in demand-valve ventilators was evaluated by using a piston pump as a simulator for active breathing. A piston pump delivered and withdrew a stroke volume of 500 ml at rates of 10, 20 and 40 cycle.min-1 with a sinusoidal waveform. A hot-wire flowmeter and a differential pressure transducer were interposed between the pump and ventilators and their signals were fed to a microcomputer to display a pressure-volume loop. The area of the loop was divided into the four parts. Inspiratory work associated with the opening of the demand valve was represented by the area of baseline airway pressure (BPa) during inspiration. The remaining area during inspiration reflected the work done by the ventilators. Expiratory work for overcoming the flow resistance of the expiratory apparatus was represented by the area above BPa during exhalation. The fourth was the area below the baseline during exhalation. The Puritan-Bennett 7200a, the Bear 5, the Siemens Servo 900C, the Hamilton Veolar, the Bird 6400ST, the Engström Erica, the Dräger EV-A, and the CPU-1 were examined at varying CPAP and pressure support levels. Because of demand valve oscillation throughout inspiration, the inspiratory workload of the Bear 5, the Siemens Servo 900C, the Hamilton Veolar, the Bird 6400ST, and the Dräger EV-A could not be calculated. Expiratory flow-resistive work was higher in the Siemens Servo 900C and the Bird 6400ST than the others. The present system can assess the entire performance of ventilators, and may serve to compare ventilators' performance.

Evaluation Studies as Topic↗
PubMed1989

[Three cases with an extensive lesion in the dependent portion of the lungs diagnosed by chest CT-scan].

Three patients whose lung diseases are diagnosed with CT-scan are reported. A patient showed severe hypoxemia without any abnormal shadow on chest X-P. CT-scan revealed a diffuse and extensive lesion in the dependent portion. We performed his respiratory care in prone position. CT-scan of the second patient with aspiration pneumonia revealed that the lesion existed in the dependent portion. Cardiogenic pulmonary edema of the third patient was found to be distributed mainly in the dependent portion by CT-scan. We consider that CT-scan is useful when chest X-P gives little information.

Humans↗
PubMed1988

[Reevaluation of direct radioimmunoassay for plasma cAMP concentration].

In order to evaluate the validity of the direct radioimmunoassay of plasma cAMP level by using Yamasa cyclic AMP assay kit, we determined the cyclic AMP concentration of normal human plasma before and after purification through anion-exchange chromatography. We found that 1) the direct assay before purification gave almost the same values as the indirect assay after purification by anion-exchange chromatography, 2) hemolysis did not affect the results of the direct assay, 3) the plasma cAMP was stable for up to 12 weeks when 5 mM EDTA was added to the blood at the time of sampling and stored below -20 degrees C and 4) the cAMP concentration did not decrease by repeated freeze-thawing of the plasma samples for up to 10 times. These results indicate that the direct radioimmunoassay of plasma cAMP concentration in normal subjects can give the same values as those obtained after purification by anion-exchange chromatography. Although further investigation is needed to clarify whether these results can be equally applied to patient's plasma with various diseases, the direct assay offers a convenient and accurate method to determine plasma cAMP concentration.

Blood Preservation↗
PubMed1988

Rapid determination of amphotericin B levels in serum by high-performance liquid chromatography without interference by bilirubin.

A high-performance liquid chromatographic method for the determination of amphotericin B concentrations in human serum without bilirubin interference was developed and compared with a microbiological assay. The high-performance liquid chromatographic assay utilized a reversed-phase trimethyl silica column, simple sample preparation, and visible detection. Reproducibility studies yielded coefficient-of-variation ranges from 1.02 to 2.11% for within-day precision and 2.88 to 4.32% for between-day precision. The correlation coefficient with the microbiological assay was 0.984 for amphotericin B.

Amphotericin B↗
PubMed1988

[Effect of combination therapy with an adriamycin-lipiodol emulsion and a mitomycin C microcapsule in hepatocellular carcinoma complicated by portal thrombosis].

An intra-arterial injection of an Adriamycin-Lipiodol emulsion and a Mitomycin C microcapsule has been given to two patients of hepatocellular carcinoma (HCC) complicated with a tumor thrombosis of the portal trunk. One patient showed a partial response, while the other evidenced no change, alpha-Fetoprotein decreasing from 4510 to 419 ng/ml in the partial response case, and from 328 to 283 ng/ml in the no change case. In each instance the hepatic injury treated by this combination therapy was mild and reversible. Bone marrow suppression by this therapy was not demonstrated. Thus, this therapy is thought to be applicable to cases of hepatocellular carcinoma complicated with a tumor thrombosis of the portal trunk who should not be indicated for transcatheter arterial embolization.

Aged↗