Intracolon Cooling Increases Survival Rate in the Rat Model of Lethal Hemorrhage

Abstract

Background The objective of this study is to investigate whether Trans-Rectal Intra-Colon (TRIC) cooling can prolong the survival duration in a rat hemorrhagic shock (HS) model. Methods A lethal-HS was induced by bleeding 47% of the total blood volume. A TRIC device was placed into the colon to maintain the intra-colon temperature either at 37 °C (TRIC37°C) or TRIC10°C pos-HS. In the surface cooling (SC) rats, the body temperatures were maintained at the same level as the esophageal temperature of the TRIC10°C rats. A separated group of TRIC10°C rats were resuscitated (Res) at 90 minutes post-HS. A total six groups were: (i) Sham-TRIC37°C (n = 5); (ii) Sham-TRIC10°C (n = 5); (iii) HS-TRIC37°C (n = 5); (iv) HS-TRIC10°C (n = 6); (v) HS-SC (n = 6); and (vi) HS-TRIC10°C + Res (n = 6). Results An average post-HS survival time was 18.4 ± 9.4 minutes in HS TRIC37°C and 82 ± 27.82 minutes in the HS SC group. In striking contrast, the HS TRIC10°C group exhibited an average survival time of 150.2 ± 66.43 minutes. The post-HS blood potassium level rose significantly in the HS-TRIC37°C and HS-SC, whereas remained unchanged in the TRIC10°C groups. Post-HS intestinal damage occurred in HS-TRIC37°C and HS-SC groups but virtually absent in HS TRIC10°C groups. Following resuscitation at 90 min post-HS, all HS-TRIC10°C rats were fully recovered from the lethal HS. Conclusions TRIC10°C reversed the high blood potassium level, prevented the intestinal damage, and prolonged the survival duration by 6-fold relative to normothermia and by 2-fold compared to SC post-HS. All TRIC10°C rats were successfully resuscitated at 90 min post-HS.