Chest
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The effect of continuous positive airway pressure (CPAP) applied via a mask covering the nose and mouth (oral-nasal CPAP = ONCPAP) on obstructive sleep apnea (OSA) was studied in ten male patients with a mean (+/- SD) age of 48.1 +/- 11.1 years who could not tolerate nasal CPAP (NCPAP) due to nasal congestion. Using ONCPAP at pressures of 11.0 +/- 4.5 cm H2O, the apnea+hypopnea index was reduced from 58.3 +/- 22.3 (baseline night) to 5.2 +/- 1.6 events per hour (ONCPAP night) (p < 0.001). Five of these patients were studied on a subsequent night with a dual chamber mask allowing separate measurement of nasal and oral flow. ⋯ In a separate study, we compared the effects of a therapeutic level of CPAP pressure (12.8 +/- 2.5 cm H2O) applied through a nasal mask (NCPAP) and ONCPAP in a different group of patients (mean age 60 +/- 14.6 years) with moderate to severe OSA using NCPAP on a long-term basis. The apnea-hypopnea indexes on NCPAP nights (7.2 +/- 3.5) and ONCPAP nights (7.6 +/- 4.9 events per hour of sleep) were very similar. We conclude that ONCPAP may be a reasonable treatment alternative in patients who cannot tolerate NCPAP due to nasal congestion and that the pressure required to maintain upper airway patency may be similar to the level required using NCPAP.
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Comparative Study
Unplanned extubation. Predictors of successful termination of mechanical ventilatory support.
Unplanned extubation (self-extubation or accidental extubation) occurs commonly in mechanically ventilated patients, and many patients do not receive mechanical ventilation indefinitely. Unfortunately, weaning parameters are often unavailable in the setting of unplanned extubation, and it would be useful to define pre-extubation respiratory and ventilatory parameters that predict which patients require reintubation. ⋯ Reintubation after unplanned extubation should not be considered mandatory. Patients who require reintubation have significantly higher preextubation FIo2 and ventilatory requirements than patients who remain extubated.
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To learn about the status of junior faculty in the specialty of pulmonary diseases and about their attitudes concerning their future in academic medicine. ⋯ The success of junior faculty is important to the success of academic medicine. More attention should be paid to ensuring protected continuous time for research, educating about promotion, and improving funding opportunities.
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We studied hemodynamic and oxygen transport parameters in 12 stable critically ill patients on assist control (ACV), synchronized intermittent mandatory (SIMV), and pressure support (PSV) ventilatory modes. Patients were optimally ventilated on ACV, were awake, and capable of spontaneous breathing. After baseline measurements on ACV, patients were placed on SIMV and PSV for 30 min each and measurements were repeated at the end of each period. ⋯ Hemodynamic and oxygen transport parameters were not significantly different among the three groups, although there was a tendency toward higher cardiac index, oxygen transport, and oxygen consumption on SIMV and PSV. We conclude that in stable critically ill patients, SIMV and PSV used according to our study protocol for 30 min can provide adequate ventilation with lower airway pressure and possibly less adverse effects on hemodynamic and tissue oxygenation parameters compared with ACV. Because of a significant decrease in VT and an increase in f seen with SIMV, PSV may be a more desirable mode for ventilatory support.
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Work of breathing necessary to trigger a ventilator (WOBtr) was calculated during pressure support ventilation (PSV), and the effect of bias flow on WOBtr was evaluated. A spring-loaded bellows type lung model with two bellows placed in series was used to simulate spontaneous breathing. A Venturi mechanism of jet flow generated subatmospheric pressure inside the diaphragm bellows simulated inspiratory effort. ⋯ With bias flow, both triggering delay and WOBtr increased. An increase in bias flow at a given PS level resulted in both decreased pressure support time and tidal volume (VT). It is concluded that the bias flow system is not desirable for use during PSV.