Noninvasive positive pressure ventilation following esophagectomy: Safety demonstrated in a pig model

BACKGROUND: Respiratory complications occur in 20% to 65% of patients who have undergone esophagectomy. While noninvasive positive pressure ventilation (NPPV) is associated with fewer complications than endotracheal intubation (ET), it is relatively contraindicated after esophagectomy due to potential injury to the anastomosis. We created ex vivo and in vivo pig models to determine the pressure tolerance of an esophagectomy anastomosis and compare it to esophageal pressure during NPPV. METHODS: We created a stapled side-to-side, functional end-to-end esophagogastric anastomosis. With continuous intraluminal pressure monitoring, we progressively insufflated the anastomosis with a syringe until we detected an anastomotic leak, and recorded the maximum pressure before leakage. We performed this experiment in 10 esophageal specimens and 10 live pigs. We then applied a laryngeal mask airway (LMA) to five live pigs and measured the pressure in the proximal esophagus with increasing ventilatory pressures. RESULTS: The perforation was always at the anastomosis. The ex vivo and in vivo anastomoses tolerated a mean of 101 ± 44 cm H₂O and 84 ± 38 cm H₂O before leak, respectively. There was no significant difference between the pressure thresholds of ex vivo and in vivo anastomoses (P = .51). When 20, 30, and 40 cm H₂O of positive pressure via LMA were delivered, the esophagus sensed 5 ± 4 cm H₂O (25%), 11 ± 11 cm H₂O (37%), and 15 ± 9 cm H 2 O (38%), respectively. CONCLUSIONS: Our pig model suggests that an esophagectomy anastomosis can tolerate a considerably higher pressure than is transmitted to the esophagus during NPPV. NPPV may be a safe alternative to ET after esophagectomy.