The American review of respiratory disease
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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.
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Am. Rev. Respir. Dis. · Jan 1991
Estimating left ventricular filling pressure during positive end-expiratory pressure in humans.
In the critically ill, accurate measurements of left ventricular (LV) filling pressure using pulmonary artery occlusion pressure (Ppao) are important for diagnostic and therapeutic purposes. In patients receiving positive end-expiratory pressure (PEEP), Ppao may not reflect LV filling pressure because of elevated pericardial pressure (Ppc). It has been proposed that in humans, Ppc and right atrial pressure (PRA) are equal, so that referencing Ppao to PRA may improve the assessment of LV filling pressure when Ppc is elevated. ⋯ PEEP was sequentially increased from zero to 15 cm H2O. We found that PRA always exceeded Ppc (p less than 0.01) and increased less with PEEP than did Ppc (p less than 0.05). At less than or equal to 5 cm H2O PEEP, both Ppao and nadir Ppao were similar to each other and to PLAtm.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Nov 1990
Determination of serum concentrations of type III procollagen peptide in mechanically ventilated patients. Pronounced augmented concentrations in the adult respiratory distress syndrome.
Type III procollagen peptide (PCP) is a byproduct of type III collagen synthesis and a potential marker of collagen secretion. In chronic diffuse interstitial lung diseases, elevated PCP concentrations have been found in serum as well as in bronchoalveolar lavage fluid. It has been proposed that PCP is a marker of early, active stages of fibrosis. ⋯ PCP concentrations in patients with ARDS were extremely elevated compared with those in control subjects (p less than 0.001) and correlated positively with FiO2 (r = 0.71, p less than 0.01). These results support the pathophysiologic concept of early fibrogenesis in ARDS. As preventing pulmonary fibrosis in ARDS is essential in improving survival rate, we believe PCP can be a valuable diagnostic tool in ARDS.
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Am. Rev. Respir. Dis. · Nov 1990
Effect of pentoxifylline on hemodynamics, alveolar fluid reabsorption, and pulmonary edema in a model of acute lung injury.
We investigated the effect of pentoxifylline (PTX) on the development of pulmonary edema in a model of adult respiratory distress syndrome in rabbits. Lung injury was induced by repeated saline lavages in adult rabbits weighing 2.5 to 3.5 kg. Rabbits pretreated with PTX (20 mg/kg bolus followed by 20 mg/kg/h infusion) developed significantly lower amounts of lung edema 4 h after saline lavage (extravascular lung water to dry weight ratio [W/D], 6.9 +/- 0.6 SD versus 8.9 +/- 0.5 in control animals). ⋯ To determine if PTX decreased lung water by accelerating active alveolar fluid reabsorption, a single 60-ml aliquot of saline was instilled into the lungs of normal rabbits treated with saline or PTX. Both groups had a similar decrease in lung water content 1 and 4 h later. Our data indicate that PTX reduces edema formation in rabbits after saline lavage, not by lowering microvascular pressures for fluid filtration or by acceleration alveolar fluid reabsorption, but possibly by its anti-inflammatory effect on neutrophil function.