Search

Fiberoptic bronchoscopy revealed an ectopic tracheal bronchus to the right upper lobe arising 3 cm above the carina. An endobronchial blocker (COOPDECH™, Osaka, Japan) was positioned in the proximal right intermediate bronchus, blocking the middle and inferior lobes. Although the right upper lobe was ventilated, it did not obstruct the surgical field via a right anterior thoracotomy. The patient was ventilated using pressure-control ventilation with inspiratory pressure 20 cm H2O, positive end-expiratory pressure (PEEP) 6 cm H2O, and tidal volume 500 mL at an FIO2 1.0 after collapse of the right middle and lower lobes. The femoral artery was cannulated with a 20-Fr arterial cannula and the femoral vein with a 28-Fr venous cannula positioned into the right atrium with the tip in the superior vena cava to establish CPB. An antegrade cardioplegia cannula was inserted into the ascending aorta with a flexible cross-clamp subsequently applied. The heart was arrested initially by using antegrade cold blood cardioplegia. Myocardial protection was provided using mild systemic hypothermia (341C), and antegrade cold blood cardioplegia was given throughout the procedure at 30-minute intervals.

Background/Purpose: Blood perfusion to the coronary artery (CA) during venoarterial (VA) extracorporeal membrane oxygenation (ECMO) was examined to determine whether it was receiving highly oxygenated ECMO blood or desaturated blood from the pulmonary circulation of diseased lungs. Methods: In the first experiment, left ventricle output and oxygen saturation in the left ventricle (LV) and CA were measured in dogs placed on VA ECMO. In the second experiment, dogs with an artificial subclavian-pulmonary artery shunt were placed on VA ECMO at 100 mL/kg/min, and oxygen saturation was measured as the shunt flow increased. Results: Without an artificial shunt, a substantial portion of coronary perfusion was found to be supplied by the left ventricle (54 + 30%), even at a high ECMO flow rate of 100 mL/kg/min and low LV output (22 + 17%) relative to ECMO flow. With a shunt, oxygen saturation in the CA was more than 95%, even when shunt flow was only 7.5% of ECMO flow and output from the left ventricle was less than 25% of the ECMO flow rate. Conclusions: These results suggest that an excessive "lung rest" strategy during VA ECMO may produce suboptimal coronary oxygenation possibly leading to myocardial damage. The presence of a small left-to-right shunt may prevent coronary hypoxia.

A multicenter randomised trial was conducted in nine neonatal centers in Japan to re-evaluate the safety and the efficacy of high frequency oscillatory ventilation using the piston type oscillator (Hummingbird) in the treatment of respiratory failure in preterm infants weighing between 750 and 2000 g at birth. A total of 92 infants were enrolled in the study. Forty-six infants were allocated to high frequency oscillatory ventilation and 46 infants to conventional mechanical ventilation. There were no differences in sex, birth weight, gestation and Apgar score between groups. The study was begun 2.0 ± 1.6 h (mean ± S.D.) after birth in the high frequency oscillation group and 1.7 ± 1.5 h after birth in the conventional mechanical ventilation group. The absence of intraventricular hemorrhage was confirmed by echography in all cases before beginning ventilation. Mortality was similar in high frequency oscillatory ventilation and conventional mechanical ventilation (0 and 2%). The incidence of intraventricular hemorrhage was also similar in the high frequency and conventional mechanical ventilation groups (15 and 13% overall; 4 and 2% in grades III and IV, respectively). Nine percent of the infants in high frequency oscillatory ventilation and 13% in conventional mechanical ventilation developed bronchopulmonary dysplasia, but the difference was not significant. The frequency of air leaks was also equal in both groups. Periventricular leukomalacia was detected in 9% of infants on conventional mechanical ventilation and 2% on high frequency oscillation, but the difference was not significant. Mean airway pressure was significantly higher in the high frequency oscillatory ventilation group and the infants on high frequency oscillation showed a significantly higher arterial to alveolar oxygen tension ratio after 6 h of treatment. These results suggest that high frequency oscillatory ventilation does not increase the risk of severe complications such as air leaks, intraventricular hemorrhage or periventricular leukomalacia when it is used by experienced neonatologists. Indeed high frequency oscillatory ventilation helps provide better oxygenation with higher mean airway pressure without increasing the risk of bronchopulmonary dysplasia and severe complications such as air leaks and intraventricular hemorrhage.