Comportamento pulmonar nos portadores de cardiopatias congênitas com hiperfluxo pulmonar após tratamento cirúrgico

Abstract

Objective: To evaluate the behavior of the pulmonary compliance and resistance of the airway passage in patients with high blood flow congenital heart disease undergoing surgical treatment with cardiopulmonary bypass. Method: The static pulmonary compliance and the airway resistance were evaluated in 35 patients during the intraoperative period, in four distinct instants: the first, before the thorax opening, with the infants being already anesthetized, under mechanical ventilation; the second, after thorax and pericardium opening, with the retractors in position; the third, five minutes after the end of cardiopulmonary bypass; the forth, after thorax closing. Pulmonary measurements were performed non-invasively by means of the airway occlusion at the end of inspiration, and the use of proper mathematical formula. In different periods, the observed and related variables with the pulmonary changes were: preoperative, the age, weight and systemic and pulmonary blood flow; intraoperative, the perfusion and the anoxia duration and the minimum body temperature; and, postoperative, duration of mechanical ventilatory support and the length of stay in the ICU. Results: At the end of the surgery, the pulmonary compliance showed a significant and immediate increase (P<0.001) in all the patients. Patients over 30-months as well as the ones with weight over 10kg showed greater increase; P=0.0004, P=0.0006, respectively. Patients with 50-minute duration of cardiopulmonary bypass delayed more to present increase of pulmonary compliance (P=0.04). The resistance of the airway passage did not present significant alteration at the end of surgical correction (P=0.393). Conclusion: All the patients presented pulmonary compliance improvement at the end of the surgery. It was influenced significantly by the age, weight and duration of cardiopulmonary bypass; however, the resistance of the airway passage has not changed.