American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · May 2000
Time course and recovery of exacerbations in patients with chronic obstructive pulmonary disease.
Although exacerbations of chronic obstructive pulmonary disease (COPD) are associated with symptomatic and physiological deterioration, little is known of the time course and duration of these changes. We have studied symptoms and lung function changes associated with COPD exacerbations to determine factors affecting recovery from exacerbation. A cohort of 101 patients with moderate to severe COPD (mean FEV(1) 41.9% predicted) were studied over a period of 2.5 yr and regularly followed when stable and during 504 exacerbations. ⋯ In the 404 exacerbations where recovery of PEFR to baseline values was complete at 91 d, increased dyspnea and colds at onset of exacerbation were associated with prolonged recovery times (p < 0.001 in both cases). Symptom changes during exacerbation do not closely reflect those of lung function, but their increase may predict exacerbation, with dyspnea or colds characterizing the more severe. Recovery is incomplete in a significant proportion of COPD exacerbations.
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Am. J. Respir. Crit. Care Med. · May 2000
Implications of extubation delay in brain-injured patients meeting standard weaning criteria.
We hypothesized that variation in extubating brain injured patients would affect the incidence of nosocomial pneumonia, length of stay, and hospital charges. In a prospective cohort of consecutive, intubated brain-injured patients, we evaluated daily: intubation status, spontaneous ventilatory parameters, gas exchange, neurologic status, and specific outcomes listed above. Of 136 patients, 99 (73%) were extubated within 48 h of meeting defined readiness criteria. ⋯ Median hospital charges were $29,057.00 higher for extubation delay patients (p < 0.001). This study does not support delaying extubating patients when impaired neurologic status is the only concern prolonging intubation. A randomized trial of extubation at the time brain-injured patients fulfill standard weaning criteria is justifiable.
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Am. J. Respir. Crit. Care Med. · May 2000
Predictors of mortality in acute respiratory distress syndrome. Focus On the role of right heart catheterization.
Right heart catheterization (RHC) has been suspected of increasing mortality. The acute respiratory distress syndrome (ARDS) is a frequent reason for RHC. We designed a retrospective cohort study of 119 consecutive ARDS patients admitted to two medical intensive care units of tertiary care hospitals in which two different approaches are used for hemodynamic monitoring: RHC on demand (Henri Mondor Hospital [HM]) and no use of RHC (Ambroise Paré Hospital [AP]). ⋯ However, administration of epinephrine/norepinephrine and a nonpulmonary cause of ARDS were each independently associated with death. It is only when administration of vasopressors was omitted from the model that RHC, septic shock, and SAPS II became independent predictors of mortality. These results suggest that: (1) the use of vasopressors, but not of RHC, represents an important prognostic factor; and (2) not taking into account the use of these drugs may be misleading when assessing the influence of RHC on outcome.
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Am. J. Respir. Crit. Care Med. · May 2000
Effects of inverse ratio ventilation and positive end-expiratory pressure in oleic acid-induced lung injury.
Continuous as well as cyclic (with each expiration) lung collapse in acute respiratory failure can be reduced by positive end-expiratory pressure (PEEP) or short expiration times, as in inverse ratio ventilation (IRV). In 20 pigs with oleic acid-induced lung edema, we compared the effects of a PEEP of 20 cm H(2)O with IRV, using an inspiratory-to-expiratory ratio of 3:1 without external PEEP. During IRV, expiration times of 0.5 or 1.0 s were obtained with respiratory rates of 30 breaths/min or 15 breaths/min, respectively. ⋯ PEEP reduced shunt and improved oxygenation to a greater extent than the two modes of IRV, although there was a large variation within each group. The improvement, irrespective of which ventilatory mode was superior in a particular pig, was caused by greater and more even aeration of the lung, whereas the perfusion distribution with PEEP was the same as with IRV. Thus, the strategy of stabilizing the lungs through short expiration times, as in IRV, did not offer any advantages in our lung injury model.
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Am. J. Respir. Crit. Care Med. · May 2000
The effect of intensive plasma water exchange by hemofiltration on hemodynamics and soluble mediators in canine endotoxemia.
High volume hemofiltration (HVHF) (200 ml/kg/h) improves hemodynamics in experimental septic shock but is difficult to apply clinically. Accordingly, we studied whether less intensive HVHF (80 ml/kg/h) can still improve hemodynamics in experimental septic shock. We also investigated its effect on the serum concentrations of several inflammatory mediators, including endothelin (ET-1), endotoxin (LPS), tumor necrosis factor-alpha (TNF-alpha), and 6-keto prostaglandin F(1alpha) (6-kepto PGF(1alpha)). ⋯ Median clearances of ET-1 and 6-keto PGF(1alpha) during intensive CVVH were 8.8 and 25.9 ml/m, respectively. We conclude that intensive CVVH attenuates the early component of endotoxin-induced hypotension and reduces serum concentrations of endothelin-1. The effect of CVVH on blood pressure is not explained by convective clearance of the mediators in question.