The American review of respiratory disease
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Am. Rev. Respir. Dis. · Sep 1993
Comparative Study Clinical TrialSafety of bronchoalveolar lavage in patients with adult respiratory distress syndrome.
Although shown to be safe in many other lung disorders, the safety of fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) in critically ill patients with adult respiratory distress syndrome (ARDS) remains unproven. We conducted a prospective study to evaluate the safety of BAL in patients with ARDS. There were 438 patients with ARDS at our institution during the study period. ⋯ One pneumothorax developed during the procedure. No deaths occurred that were related to the procedure. We conclude that FOB and BAL can be performed safely and are reasonably well-tolerated in patients with ARDS.
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Am. Rev. Respir. Dis. · Sep 1993
Comparative StudyOptimizing alveolar expansion prolongs the effectiveness of exogenous surfactant therapy in the adult rabbit.
We evaluated four ventilator patterns after the administration of 80 mg/kg bovine lipid extract surfactant (LES) to anesthetized, paralyzed, saline-lavaged New Zealand white rabbits. Two ventilator types were compared: high frequency oscillatory ventilation (HFO) versus conventional mechanical ventilation (CMV), each at high (HI) and low (LO) end-expiratory lung volumes (EELV); n = 6, each group; treatment duration = 4 h. Target PaO2 ranges were > 350 mm Hg for groups with high EELV (i.e., HFO-HI and CMV-HI) and 70 to 100 mm Hg for those with low EELV (i.e., HFO-LO and CMV-LO). ⋯ The deflation P-V curve (p = 0.0004), lamellar body (p < 0.00001) and lavage fluid (p = 0.0002) phospholipid levels were superior after the high EELV strategy. We conclude that ventilator pattern strongly influences exogenous surfactant efficacy. Benefits arise from keeping EELV high enough to prevent atelectasis and using small (approximately 2 ml/kg) tidal volumes to prevent overdistension.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Sep 1993
Comparative StudyComparison of ventilatory support with intratracheal perfluorocarbon administration and conventional mechanical ventilation in animals with acute respiratory failure.
We investigated the efficacy of intratracheal perfluorocarbon (PFC) administration combined with mechanical ventilation to support gas exchange in adult animals with acute respiratory failure. These were compared with a similar group of animals treated with continuous positive-pressure ventilation (CPPV) with respect to respiratory parameters and postmortem lung histology. After lung lavage with saline, 18 adult rabbits were divided into three groups (n = 6 per group). ⋯ Only in the PFC group were significant decreases in airway pressures and increase in respiratory system compliance seen. In the CPPV group, PaO2 stayed around 60 mm Hg and PaCO2 gradually increased. PFC treatment with conventional mechanical ventilation in acute respiratory failure proved to be a successful supportive technique to improve gas exchange at low inflation pressures.
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Am. Rev. Respir. Dis. · Aug 1993
Bicarbonate does not increase left ventricular contractility during L-lactic acidemia in pigs.
Lactic acidosis decreases left ventricular contractility, but whether bicarbonate increases left ventricular contractility during lactic acidosis in vivo is controversial. Therefore, we measured hemodynamics and left ventricular mechanics before and after bicarbonate administration during L-lactic acid infusion in 15 anesthetized pigs. The pigs were beta-blocked and atrially paced to minimize indirect effects of acidosis on contractility. ⋯ These effects were not significantly different from the effects of saline. Bicarbonate did not significantly increase Emax (4.2 +/- 0.8 to 4.9 +/- 0.8 mm Hg/ml) and was indistinguishable from saline (5.0 +/- 0.7 to 5.2 +/- 0.7 mm Hg/ml). We conclude that bicarbonate infusion does not directly increase left ventricular contractility during lactic acidemia in pigs within this pH range.
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Am. Rev. Respir. Dis. · Aug 1993
Effects of periodic obstructive apneas on venous return in closed-chest dogs.
With sleep apnea syndrome, mean cardiac output (CO) may fall. This implies a fall in venous return (VR) that is equal to the product of the pressure gradient for VR (GVR)--mean circulatory pressure (MCP)--right ventricular end-diastolic pressure and the conductance for VR (Gv). During airway obstruction there could also be shifts of blood volume between central and peripheral circulatory compartments. ⋯ With RA apneas, GVR and MCP increased by 55% (p < 0.05) and Gv decreased by 63% (p < 0.05). On O2, there were no changes in GVR or Gv, and changes in CO were predictable from the baseline VR curve. With O2 there was an increase in central blood volume by 21.0% (p < 0.01) during the apneic phase.(ABSTRACT TRUNCATED AT 250 WORDS)