Effects of one-lung ventilation on pulmonary hemodynamics and gas exchange in the newborn.

Abstract

For major thoracoscopic surgery, one-lung ventilation is mandatory. This is reasonably well tolerated in adults and children. The effects of one-lung ventilation on hemodynamics and gas exchange in newborns, however, are not known yet. Eight neonatal domestic pigs with a median age of 6 days (range: 3-9 days), and a mean body weight of 2.3 kg (1.7-2.8 kg) were intubated and ventilated in pressure-controlled mode (FIO2 = 1). Anesthesia was maintained with i.v. fentanyl/metomidate. After tracheotomy an endotracheal tube was positioned in the trachea, and a second tube in the left mainstem bronchus. One-lung ventilation was maintained for 120 min. Serial measurements were done before, during, and until 90 min. after one-lung ventilation. During one-lung ventilation, pulmonary artery pressure and intrapulmonary shunt increased from 15 +/- 1 to 18 +/- 1 mmHg (p = 0.004), and from 2.6 +/- 0.3 to 3.7 +/- 0.4% (p = 0.02), respectively. Arterial oxygen saturation remained unchanged at 100%. A slight increase in arterial PCO2 could easily be treated by increasing the respiratory rate. In conclusion, one-lung ventilation was not associated with major side effects in regard to hemodynamics and gas exchange in the neonatal pig.