Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1976
Effect of mechanical ventilation with end-inspiratory pause on blood-gas exchange.
The effects of end-inspiratory pause (EIP) on gas exchange were measured in 10 adult patients with acute respiratory insufficiency while maintained on mechanical ventilation. Four inspiratory patterns were studied with a constant tidal volume (10 to 15 ml/kg body weight), respiratory rate (9 to 12 breaths/min), FIO2 (0.5) and end-expiratory pressure. Inspiratory flow rate (V insp) and EIP time were varied to produce a control pattern (V insp = 60 L/min, EIP = 0), 2 EIP patterns of 0.6 and 1.2 seconds with a similar V insp and a "slow" flow pattern (V insp = 30 L/min) without EIP. ⋯ Arterial oxygenation was unchanged with both EIP and "slow" flow patterns when compared to control. Dead-space ventilation (VD/VT) and Paco2 were significantly decreased (p less than 0.01) as EIP was increased from 0 to 1.2 seconds, but remained unchanged with slow inspiratory flow. Thus, EIP improved the efficiency of ventilation with no apparent improvement in oxygenation in patients with acute respiratory insufficiency.
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Anesthesia and analgesia · Jan 1976
Circulatory changes during anesthetic induction: impact of d-tubocurarine pretreatment, thiamylal, succinylcholine, laryngoscopy, and tracheal lidocaine.
Circulatory changes after IV d-tubocurarine (3 mg), thiamylal (4 mg/kg) plus succinylcholine (2 mg/kg) and followed by direct laryngoscopy with or without intratracheal lidocaine spray (2 mg/kg) just before endotracheal intubation (EI), were measured in 40 adult patients. Pretreatment with d-tubocurarine did not alter mean arterial pressure (MAP), heart rate (HR), or central venous pressure (CVP). One minute after thiamylal-succinylcholine and just before laryngoscopy, MAP was 15 torr less than the awake value (p less than 0.05) and HR was 13 beats/min greater than the awake value (p less than 0.05). ⋯ However, the pressor and HR changes following EI were more transient when tracheal lidocaine was used (20 patients) and these patients were more likely to tolerate the tracheal tube without immediate additional anesthesia. The incidence of ventricular dysrhythmias was not altered by tracheal lidocaine. Compared with awake values, the cardiac index did not change significantly following intubation but stroke volume was decreased (p less than 0.05), with or without tracheal lidocaine.
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Anesthesia and analgesia · Jan 1976
Cardiovascular effects of enflurane and halothane on the rhesus monkey.
Ten rhesus monkeys were chronically instrumented to compare the cardiovascular effects of enflurane and halothane. In 17 experiments, each monkey was evaluated in the awake state and after equilibration at each of many anesthetic levels. End-expired gas concentrations were expressed in multiples of human minimum alveolar concentrations (MAC) for comparison. ⋯ At equal MAC levels, no significant differences were detected between halothane and enflurane. Cardiac output and aortic flow acceleration were obtained on one of the animals for both agents. Results were consistent with those for the other measured parameters.