Closing volume measurement was adapted for application in apneic intubated, artifically ventilated subjects. A bolus of nitrogen was used as the marker gas. Inspiration and exhalation at a slow, uniform rate between residual volume and total lung capacity was provided by a 7000-ml syringe. Closing volumes in seven anesthetized subjects were similar to those reported for supine, conscious individuals by previous investigators. This adaptation of closing volume measurement should be useful in studying pulmonary dysfunction during anesthesia and during artificial ventilation of patients in respiratory failure.

Adult↗

PubMedDate not supplied

Halothane and enflurane protect against bronchospasm in an asthma dog model.

Experimental asthma was induced in 6 dogs previously sensitized to ascaris antigen by ventilating them with aerosolyzed ascaris antigen for 10 minutes. Pulmonary resistance was calculated from simultaneous pressure and flow measurements at a long volume 200 ml above functional residual capacity. Prior to administration of aerosolyzed ascaris antigen, pulmonary resistance was 2.35 +/- 0.56 (mean +/- SEM) cm H2O/L/sec in dogs anesthetized with thiopental. Twenty minutes after the end of ascaris antigen administration, pulmonary resistance was 5.72 +/- 1.29 in dogs given additional thiopental, 3.18 +/- 0.62 in dogs anesthetized with halothane (0.87% inspired concentration), and 3.03 +/- 0.60 in dogs anesthetized with enflurane (2.2% inspired concentration). These differences in responses of pulmonary resistance were statistically significant at 0.05 level. Halothane and enflurane were equally effective in decreasing pulmonary resistance in an ascaris antigen dog model of asthma.

Airway Resistance↗

PubMedDate not supplied

Components of the alveolar-arterial oxygen tension difference in anesthetized man.

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Adult↗