Chest
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Comparative Study
Gas exchange during mechanical ventilation and spontaneous breathing. Intermittent mandatory ventilation after open heart surgery.
Pulmonary gas exchange rates in eight patients after open heart surgery were studied during weaning from the ventilator. We investigated continuous positive pressure ventilation (CPPV), intermittent mandatory ventilation (IMV) and spontaneous breathing with continuous positive airway pressure (CPAP). During each mode of ventilation we measured: CO2 production (VCO2), O2 consumption (VO2), cardiac output (CO), PaO2, Qs/QT and functional residual capacity (FRC). ⋯ The latter result is discussed on the basis of two mechanisms: Vds was reduced and alv eff CO2 was increased. We conclude that compared to CPPV, IMV decreases mean alveolar pressure and reduces dead space ventilation at constant FRC and with constant oxygenation. This may explain why, in the weaning process, IMV makes it possible to start spontaneous breathing very early.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathoracic intercostal nerve block with phenol in open chest surgery. A randomized study with statistical evaluation of respiratory parameters.
Seventy-three patients who underwent thoracic surgery were randomly selected for intraoperative intercostal nerve block using phenol (32 block and 41 control subjects). The patients were divided into three groups: pneumonectomies, lobectomies and explorative thoracotomies and evaluated by pain level, respiratory function parameters (VT, IRV, ERV, VC) and blood-gas analysis, both six and 24 hrs after surgery. The patients who had intraoperative nerve block using phenol enjoyed a more comfortable postoperative period. In particular, respiratory parameters were statistically better.
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Randomized Controlled Trial Comparative Study Clinical Trial
Esophageal gastric tube airway vs endotracheal tube in prehospital cardiopulmonary arrest.
We evaluated the efficacy of the esophageal airway (EA) by prospectively randomizing 175 prehospital cardiopulmonary arrest patients to receive either an esophageal gastric tube airway (EGTA) or an endotracheal tube (ET). If attempts with the initial airway failed, the alternate airway was attempted. The cost of training paramedics in EA use was considerably less than the ET ($80 vs $1,000). ⋯ The incidence of neurologic residual (ET 50 percent, EGTA 36.4 percent) and congestive heart failure (ET 40 percent, EGTA 45.5 percent) in surviving ET and EGTA patients did not differ (NS). An additional 125 consecutive patients with only the opportunity to receive an EA were also evaluated and did not differ in mortality, neurologic residual, or congestive heart failure from ET patients. We conclude that the EA is a satisfactory alternative to the ET for short-term prehospital use in cardiopulmonary arrest patients.
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Continuous positive pressure ventilation is associated with a reduction in left ventricular preload and cardiac output, but the mechanisms responsible are controversial. The decrease in left ventricular preload may result exclusively from a decreased systemic venous return due to increased pleural pressure, or from an additional effect such as decreased left ventricular compliance. To determine the mechanisms responsible, we studied the changes in cardiac output induced by continuous positive pressure ventilation in eight patients with the adult respiratory distress syndrome. ⋯ As positive end-expiratory pressure increased from 0 to 20 cm H2O, stroke volume and biventricular end-diastolic volumes fell about 25 percent, and biventricular ejection fraction remained unchanged. At 20 cm H2O positive end-expiratory pressure, volume expansion for normalizing cardiac output restored biventricular end-diastolic volumes without markedly changing biventricular end-diastolic transmural pressures. The primary cause of the reduction in left ventricular preload with continuous positive pressure ventilation appears to be a fall in venous return and hence in right ventricular stroke volume, without evidence of change in left ventricular diastolic compliance.
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A 57-year-old woman with squamous carcinoma of the right lung (hilum) developed acute massive hemoptysis with syncope and hypotension. Resuscitation was complicated by the development of massive systemic air embolus, and the patient died.