Neonatal pneumothorax pressures: determination in a randomised experimental study in a in vivo animal model (original) (raw)

Background: Recruitment maneuvers (RM) pursue reversing atelectasis during general anesthesia but are associated with potential risks such as pneumothorax. Objective: To determine pneumothorax pressures in newborns using healthy piglets less than 48 hours old. Animals and Methods: Ten healthy Landrace-Large White piglets (weight 3.2 ± 0.5 kg) were put under anesthesia with bilateral chest tube catheterization and then randomly allocated into two groups: one with positive end-expiratory pressure (PEEP) and fixed inspiratory driving pressure (IDP) of 15 cm H2O (PEEP group), and the second one with ZEEP (PEEP = 0 cm H2O) and non-fixed IDP (ZEEP group). Both groups had pressure-controlled ventilation. Maximal inspiratory pressure (MIP) was raised at two-minute intervals with steps of 5 cm H2O until air leak was observed through the chest tubes. Results: MIP causing pneumothorax was 90.50 ± 15.71 cm H2O with no statistically significant difference between the two groups. This MIP matches pneumothorax pressures previously described in adult cadavers and are similar to those in an ex vivo open thorax rabbit model. Several limitations apply to the study such as no CT confirmation of barotrauma or absence of histological study. Conclusions: This is the first study done determining pneumothorax pressures in an in vivo model. Performing RM in healthy newborns is a safe procedure in terms of pneumothorax within the usual pressure range described in the literature.