Theophylline toxicity in a premature neonate - Elimination kinetics of exchange transfusion

Exchange transfusion was utilized in the treatment of a 1871 gram female, 32 weeks gestational age, who received an IV bolus of aminophylline at 11 h for the treatment of apnea, with subsequent tachycardia and hypotension. At 22 h, plasma theophylline was 369.29 μmol/L (67 mg/L). During a single volume exchange transfusion at 33 h, the plasma theophylline decreased 19% and the estimated removal of theophylline was 13.5% of the whole body theophylline. The theophylline apparent half-times before, during, and after the exchange were 52.5, 6.6, and 53.3 h respectively.