The influence of hemorrhagic shock on ventilation through needle cricothyroidotomy in pigs

Abstract

BackgroundThe aim of this study was to examine the effects of controlled hemorrhage and shock on oxygenation and ventilation using needle cricothyroidotomy and jet ventilation in an animal model. MethodsTwenty-four male pigs were randomly allocated into 4 groups: SHOCK (animals in hemorrhagic shock only), CRICH (animals that underwent needle cricothyroidotomy only), SHOCK+CRICH (animals in hemorrhagic shock + needle cricothyroidotomy), and SHAM (anesthetized animals submitted to surgical preparation only). All animals were surgically prepared and were observed for a period of 40 minutes (T0 − T40). Hemodynamic and blood gas variables were compared using analysis of variance and Bonferroni post hoc testing at a level of significance of 95%. ResultsCRICH and SHOCK+CRICH developed respiratory acidosis, with a progressive decrease of arterial pH after T20, and they presented a significant increase of PaCO2 levels after T10, when compared with SHAM and SHOCK (P < .001). When SHOCK+CRICH was compared with CRICH, it presented a larger increase of PaCO2 after T10 (P = .036) and an even more significant increase after T20 (P = .009). ConclusionHemorrhagic shock anticipated and intensified the retention of carbon dioxide and respiratory acidosis during manual jet ventilation through needle cricothyroidotomy in comparison with animals with jet ventilation but without shock. The results found in this work should be considered in future protocols for the assistance of victims of trauma in prehospital settings.