Masui. The Japanese journal of anesthesiology
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Comparative Study
[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. ⋯ 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.
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Case Reports
[Anesthetic management of a patient with Conradi's syndrome (chondrodysplasia punctata)--a case report].
Conradi's syndrome is a rare hereditary disease characterized by punctate epiphyseal calcifications. The symptoms include short stature, typical facies with hypertelorism, saddle nose, short neck, tracheal stenosis and scoliosis. ⋯ This is a report on a girl with Conradi's disease who developed respiratory problems due possibly to gastric aspiration during ophthalmic surgery under general anesthesia. Several anesthetic problems raised by this case are discussed.
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The respiratory flow velocity of 74 infants under halothane-nitrous oxide-oxygen anesthesia was measured, and the statistical relationship between the age in months and the flow velocity was obtained with least square method. The flow resistance of endotracheal tubes (size of 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0 mmI. ⋯ The mean flow resistance and respiratory work with each size of endotracheal tube were calculated by simulation technique using these data. These data coincided well with the data obtained by calculation based on in vitro experiments.
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Cardiopulmonary bypass (C-P bypass) was performed on two patients who had not responded to conventional cardiopulmonary resuscitation (CPR). The first patient, a 56-y-o male, with bilateral pulmonary thromboembolism repeatedly underwent cardiac massage and electric defibrillation for recurrent ventricular fibrillation. A veno-arterial bypass route was prepared during cardiac massage, and bypass circulation was started 3 hours after the onset of the first ventricular fibrillation. ⋯ Emergency veno-arterial bypass for CPR is effective means to maintain life until the cardiopulmonary and cerebral functions are restored. Recent advances in emergency C-P bypass are introduced and a new acronym extracorporeal lung and heart assist, ECLHA, is proposed. Emergency ECLHA with veno-arterial cannulations through percutaneous puncture will become a promising adjunct of cardiopulmonary-cerebral resuscitation in the near future.
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The changes in arterial partial pressure of oxygen were studied following intravenous injections of either ephedrine, 0.2mg.kg-1, or phenylephrine 2.5 micrograms.kg-1, to restore arterial hypotension. Eighty one adult patients underwent general anesthesia, being mechanically ventilated, were divided into two groups; both lung ventilation group (68 patients) and one lung ventilation group (13). In both lung ventilation group, PaO2/FIO2 changed from 390 +/- 132 to 400 +/- 137 mmHg, and 428 +/- 124 to 438 +/- 136 following administrations of ephedrine and phenylephrine, respectively. ⋯ In the one lung ventilation group, PaO2/FIO2 did not change significantly from 190 +/- 45 to 186 +/- 29 with ephedrine and 267 +/- 138 to 317 +/- 230 with phenylephrine. We observed neither arrhythmia, severe hypoxemia, nor decrease in PaO2/FIO2 by more than 100mmHg. These results indicate that with respect to changes in arterial partial pressure of oxygen, the clinical doses of ephedrine and phenylephrine can be safely administered to patients under general anesthesia to restore arterial hypotension.