INTRACOLON COOLING INCREASES SURVIVAL RATE IN THE RAT MODEL OF LETHAL HEMORRHAGE

Background: The objective of this study was to investigate whether transrectal intracolon (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 intracolon temperature either at 37°C (TRIC37) or at 10°C (TRIC10) post-HS. In the surface cooling (SC) rats, the body temperatures were maintained at the same level as the esophageal temperature of the TRIC10 rats. A separated group of TRIC10 rats were resuscitated (Res) at 90 min post-HS. A total of six groups were as follows: (i) Sham TRIC37 (n = 5), (ii) Sham TRIC10 (n = 5), (iii) HS TRIC37 (n = 5), (iv) HS TRIC10 (n = 6), (v) HS SC (n = 6), and (vi) HS TRIC10 + Res (n = 6). Results: An average post-HS survival time was 18.4 ± 9.4 min in HS TRIC37 and 82 ± 27.82 min in the HS SC group. In striking contrast, the HS TRIC10 group exhibited an average survival time of 150.2 ± 66.43 min. The post-HS blood potassium level rose significantly in the HS TRIC37 and HS SC, whereas it remained unchanged in the TRIC10 groups. Post-HS intestinal damage occurred in HS TRIC37 and HS SC groups but virtually absent in HS TRIC10 groups. After resuscitation at 90 min post-HS, all HS TRIC10 rats were fully recovered from the lethal HS. Conclusions: TRIC10 reversed the high blood potassium level, prevented the intestinal damage, and prolonged the survival duration by sixfold relative to normothermia and by twofold compared with SC post-HS. All TRIC10 rats were successfully resuscitated at 90 min post-HS.