The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

INDEPENDENT LUNG VENTILATION IN A PATIENT WITH COMPLEX CONGENITAL HEART DISEASE.

Donna Levine MEd, RRT, Tina Carmichael RRT, Peter C. Laussen MD, BS, Children's Hospital, Boston, MA

Independent lung ventilation (ILV) has been beneficial in treating unilateral lung disease when there are significant differences in mechanics between the two lungs^{1,2}. We report the use of ILV in a 22 year old women with respiratory failure and circulatory collapse who was referred to our ICU for ECMO. She had a history of complex congenital heart disease including double outlet right ventricle, pulmonary atresia and hypoplastic left ventricle. She underwent several surgical palliations resulting in a single ventricle heart with limited pulmonary blood flow (PBF). An aortic-to-pulmonary artery central shunt supplied pulsatile PBF to the left lung and RUL. A "classic" Glenn shunt (SVC -to-right pulmonary artery) supplied non-pulsatile PBF to the RML and RLL. Effective PBF to the RML and RLL was therefore dependent on passive, non-pulsatile flow and a transpulmonary pressure gradient between the SVC pressure and the left atrial pressure. Prior to this illness she was active with a baseline room air SpO_{2} of 85%. Her admission ABG was PaO_{2} 42 mmHg, PaCO_{2} 44 mmHg, pH 7.15 on PCV, FiO_{2} 1.0, PiP/PEEP 28/6 cmH_{2}O, rate 12. SpO_{2} was 55%, CXR showed opacification of the left lung and hyperinflation of the right lung and she required vasopressors. There was no response to 40 ppm of inhaled nitric oxide. Because of the variable lung pathology and pulmonary vascular physiology, a 35FG left endobronchial tube was placed and ILV instituted. Two Servo 900C ventilators were synchronized and a Vt of 5 cc/kg was delivered to each lung. PiP/PEEP on the right lung was 17/4 cmH_{2}O and 28/8 cmH_{2}O on the left lung. The 24 hour CXR showed the right lung with normal inflation and the left lung was expanded. SpO_{2} was 85% on FiO_{2} of 0.55. Vasopressors were reduced, ABGs and hemodynamics improved. She was extubated on day 5 and discharged on day 8. This case demonstrates the advantage of ILV in a patient with abnormal pulmonary blood flow and variable lung mechanics. Following a Glenn anastomosis, effective passive PBF, and therefore venous return to the systemic ventricle, may be severely limited by the use of high intrathoracic pressure during mechanical ventilation. ILV, in this case, enabled reduced ventilator pressures and normal inflation to the lung supplied by the Glenn shunt, with immediate improvement in arterial oxygenation and blood pressure.

1. Ost D, Corbridge T: Independent lung ventilation. Clinics in Chest Med 17:591-601, 1996

2. Schmitt HJ, Mang H, Kirmse M: Unilateral lung disease treated with patient-triggered independent lung ventilation: a case report. Resp Care 39:906-911, 1994

The 44th International Respiratory Congress Abstracts-On-DiskĀ®, November 7 - 10, 1998, Atlanta, Georgia.

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