Use of pleural alkaline phosphatase content to diagnose tuberculous effusions.

ing changes in end-expiratory thoracic gas volume. Chest 1989; 96:613-16 3 Gay PC, Rodarte JR. Hubmayr RD. The effects of positive expiratory pressure on isovolume flow and dynamic hyperinflation in patients receiving mechanical ventilation. 4 Smith TC, Marmni JJ. Impact of PEEP on lung mechanics and work of breathing in severe airflow obstruction. 5 Kimball WR, Leith DE, Robins AG. Dynamic hyperinflation and ventilator dependence in chronic obstructive pulmonary disease. BD, et al. Respiratory mechanics in mechanically ventilated patients with respiratory failure.tance ofexpiratory positive-pressure systems. Labetalol To the Editor: We read with interest the report by Gonzalez and Ram' on the treatment ofhypertensive urgencies and emergencies and the letter by Mitchell and Sirgotm regarding recommended rates and cumulative doses of intravenous (IV) labetalol (Normodyne or Trandate). Most experience has focused on short-term intermittent or continuous IV infusion with adequate response attained below the 300-mg maximum cumulative doise... We report the usage (if long-term continuous infusion of labetalol in controlling the hypertension of a 40-year-old, 80-kg black man, who was admitted to our medical intensive care unit after cardiac and respiratory arrest with hypoxic encephalopathy. His blood pressure of 320/156 mm Hg omn admission was controlled initially with nitroprusside, 0.5 p.g/kg/min, and then replaced after 36 hours with a continuous infusiomn of labetalol. A continuous infusion of labetalol was used for 5 days at a rate of 20 to 30 mg/h, with blood pressure controlled between 154/94 and 134t77 mm Hg. No adverse effects on heart rate or resolving acute renal failure were noted. The patient was transferred to) a nursing ward on a regimen of 200 mg oforal labetalol every 6 h via nasogastric tube. The patient required a daily dose of480 to 720 mg ofIV labetalol. While dosage guidelines suggest that some patients may require 1.2 to 2.4 g of oral labetaloil daily, the same guidelines recommend stopping IV labetalol at the 300-mg cumulative dose.. No controlled trials exist to guide the clinician in long-term continuous labetalol infusion; however, a recent case report summarizes experience to date and documents usage of 120 to 180 mg/h for 14 days in a trauma patient.6