Critical care medicine
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Critical care medicine · Apr 1987
Increased pulmonary alveolar-capillary permeability in patients at risk for adult respiratory distress syndrome.
Two methods for predicting adult respiratory distress syndrome (ARDS) were evaluated prospectively in a group of 81 multitrauma and sepsis patients considered at clinical high risk. A popular ARDS risk-scoring method, employing discriminant analysis equations (weighted risk criteria and oxygenation characteristics), yielded a predictive accuracy of 59% and a false-negative rate of 22%. ⋯ Lung scanning achieved a predictive accuracy of 71% (after excluding patients with unilateral pulmonary contusion) and gave no false-negatives. We propose a combination of clinical risk identification and functional determination of PACP to assess a patient's risk of developing ARDS.
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Mechanical ventilatory support of bronchoscopic procedures by conventional volume-cycled ventilation (VCV) is technically difficult and can result in unreliable gas delivery or excessive alveolar pressure. An alternate support mode is jet ventilation through an open, uncuffed endotracheal tube. To quantitate gas delivery and airway pressures (Paw) during bronchoscopy using this technique, we used a mechanical-lung model and 15 human subjects. ⋯ VCV with a deflated cuff provided much lower levels of ventilation, although Paw levels were also low. These delivered minute ventilations, and Paw levels were similar in six normal volunteers jet ventilated through a 9-mm jet endotracheal tube with a bronchoscope in place. Finally, in nine patients requiring mechanical ventilatory support during bronchoscopic procedures, this jet technique provided alveolar ventilation (i.e., PaCO2) and Paw levels comparable to those obtained on baseline VCV before bronchoscopy.
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Critical care medicine · Apr 1987
Case ReportsAtrial fibrillation with high degree atrioventricular block masquerading as ventricular fibrillation masquerading as asystole during cardiac arrest.
Ventricular fibrillation (VF) can masquerade as asystole. We report a 54-yr-old male in cardiac arrest who, on surface ECG, appeared to be in VF or asystole. ⋯ AF with a high degree block can masquerade as VF, which simultaneously masquerades as asystole, and can be correctly diagnosed by bedside intracardiac monitoring. Patients who have a flat line rhythm which may represent asystole, fine ventricular fibrillation, or atrial fibrillation with a high degree atrioventricular block may warrant a trial of electrical countershock, high-dose atropine, or transthoracic pacing.
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Tracheal wall movement can affect the lateral wall pressure and seal of an endotracheal cuff. This paper studies the relationship between proximal airway pressure (Paw) and the pressure in high-volume, low-pressure, tracheal tube cuffs. ⋯ Thus, adequate gas flow in the ventilator circuit cannot assure minimal pleural pressure changes. Decreases in cuff pressure may indicate inadequate CPAP and may explain why "just seal" pressure in endotracheal cuffs may not always prevent aspiration.