The American review of respiratory disease
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Am. Rev. Respir. Dis. · Apr 1991
Factors determining pulmonary deposition of aerosolized pentamidine in patients with human immunodeficiency virus infection.
Although aerosolized pentamidine (AP) has recently been approved for prophylaxis and is undergoing clinical trials for treatment of pneumocystis, pneumonia (PCP), factors important in the deposition of AP have not been described. Using radioaerosol techniques, deposition was measured in 22 patients receiving AP for prophylaxis or treatment of PCP. In all patients total and regional deposition of pentamidine, breathing pattern, pulmonary function (PFT), regional ventilation, and type of nebulizer were analyzed. ⋯ The major factor influencing pentamidine deposition was aerosol delivery (mg deposited versus mg inhaled; r = 0.963, p less than 0.0001; n = 26). The nebulizer was an important determinant of aerosol delivery, with the AeroTech delivering between 2.5 and 5 times more drug than the Respirgard. These observations are important in assessing treatment failure and cost of therapy.
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Am. Rev. Respir. Dis. · Mar 1991
Randomized Controlled Trial Clinical TrialPressure-time product during continuous positive airway pressure, pressure support ventilation, and T-piece during weaning from mechanical ventilation.
The objective of this study was to compare the effects of continuous positive airway pressure (CPAP), pressure support ventilation (PS), and T-piece on the pressure-time product (PTP) during weaning from mechanical ventilation. The PTP is an estimate of the metabolic work or oxygen consumption of the respiratory muscles. We studied 10 intubated patients recovering from acute respiratory failure of various etiologies. ⋯ The contribution of the decrease in PEEPi to the reduction in PTP(es) amounted to 36%. With PS-5, respiratory system mechanics and PEEPi were not significantly different compared with T-piece. With CPAP-0, PTP tended to be lower than with T-piece.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Mar 1991
Decreased oxyhemoglobin affinity in patients with sleep apnea syndrome.
Oxyhemogloblin affinity (P50 at pH 7.4, PaCO2 = 40 mm Hg, temperature = 37 degrees C) and 2,3-DPG concentration were assessed in 15 nonsmokers (14 men and one woman 46 to 63 yr of age) with sleep apnea syndrome (SAS) and in 10 normal subjects (eight men and two women 22 to 48 yr of age). In patients with SAS, mean nocturnal apnea index was 46 +/- 20/h, and mean nocturnal SO2 was 86 +/- 6% versus 94.6 +/- 1.8% during the daytime. Daytime mean P50 of the patients was 28.5 +/- 1.2 mm Hg versus 27.1 +/- 0.3 mm Hg in the normal subjects (p less than 0.05). ⋯ P50 and 2,3-DPG both decreased and returned to normal values. In conclusion, the oxyhemoglobin dissociation curve is shifted to the right in patients with SAS and there is an increase in 2,3-DPG. These could be protective mechanisms against the development of polycythemia, pulmonary hypertension, and cor pulmonale.