Hypophosphatemia induced by mechanical ventilation in patients with chronic obstructive pulmonary disease.

The aim of this study was to assess prospectively the variations of serum phosphorus concentration (P) after onset of mechanical ventilation (MV) in patients with chronic obstructive pulmonary disease (COPD) and acute respiratory acidosis. In 14 COPD patients, we measured P, PaCO2, and pH, immediately before MV (H0), then one hour (H1), 4 (H4), 7 (H7), 12 (H12), and 24 h (H24) after starting MV. P at H0 was in or above the normal range in ten patients and below normal range in four patients. P decreased significantly (p less than .001) after MV at H1, H4, H7, H12, and H24. Hypophosphatemia was present in all patients after MV, but was severe (p less than .3 mmol/L) in only two patients. There was a significant correlation (r = .56 p less than .01) between the decrease of P and the increase of pH after MV. Hypophosphatemia was a constant and early finding after institution of MV in COPD patients and was presumably related to an intracellular shift of P secondary to the correction of respiratory acidosis.

Cardiac arrhythmias during the combined use of intravenous aminophylline and terbutaline in status asthmaticus.

The purpose of this study was to evaluate prospectively the occurrence of cardiac arrhythmias during the combined therapy with intravenous aminophylline and terbutaline in 29 consecutive patients with status asthmaticus. The 24-hour Holter recordings were performed during continuous intravenous infusions of aminophylline (0.56 +/- 0.20 mg/kg/h) and terbutaline (0.034 +/- 0.014 microgram/kg/min). Serum theophylline concentration was 12.1 +/- 3.8 micrograms/ml and never reached the toxic level (greater than 20 micrograms/ml). Premature ventricular contractions (PVCs) were absent in 35 percent of patients and 48 percent had rare unifocal PVCs (less than 10/h). Only 17 percent of patients (five of 29) exhibited severe ventricular arrhythmias: PVCs greater than 10/h (n = 3), multifocal PVCs (n = 1); and a short run of ventricular tachycardia (n = 1). Serious supraventricular arrhythmias occurred in only 7 percent of patients (two of 29) who developed sustained runs of atrial tachycardia. These arrhythmias were always clinically well tolerated and spontaneously resolved without any antiarrhythmic treatment. We conclude that severe arrhythmias are rarely observed during combined therapy with aminophylline and terbutaline in status asthmaticus.