The Influence of Airway Closure Technique for Right Pneumonectomy on Wall Tension During Positive Pressure Ventilation: An Experimental Study

Bronchopleural fistula (BPF) remains a significant source of morbidity and mortality after right pneumonectomy (RPN). Postoperative mechanical ventilation represents a primary risk factor for BPF. We undertook an experiment to determine the influence of airway diameter on suture line tension during mechanical ventilation after RPN. RPN was performed in 6 fresh human adult cadavers. After initial standard bronchial stump closure (BSC), the airway suture lines were subjected to 5 cm H₂O incremental increases in airway pressures beginning at 5-40 cm H₂O. To minimize airway diameter, a carinal resection was then performed with trachea to left main bronchial anastomosis and the airway suture lines subjected to similar incremental airway pressures. Wall tension (N/m) at the suture lines was measured using piezoresistive sensors at each pressure point. As delivered airway pressure increased, there was a concomitant increase in wall tension after BSC and carinal resection. At every point of incremental positive pressure, wall tension was however significantly lower after carinal resection when compared to BSC (P < 0.05). Additionally the differences in airway tension became even more significant with higher delivered airway pressure (P < 0.001). Airway diverticulum after BSC leads to significantly increased tension on the bronchial closure with positive airway pressure as compared to a closure which minimize airway diameter after RPN. This supports the role of Laplacian Law where small increases in airway diameter result in significant increases on closure site tension. Techniques which reduce airway diameter at the airway closure will more reliably reduce the incidence of BPF following RPN.