An experimental model for the study of transcapillary fluid balance in hypothermia

Disturbed fluid balance is a significant clinical problem in hypothermia and rewarming. We have therefore investigated whether the transcapillary fluid balance in rats exposed to hypothermia and rewarming could be studied with the use of a wick method. Double nylon wicks were sewn into the abdominal skin and left there for one hour, then removed to double-bottomed conic vials and centrifuged. Wick fluid was collected and colloid osmotic pressure measured. Blood samples were taken simultaneously for measurement of hematocrit, hemoglobin, red cell count and plasma colloid osmotic pressure. This was done at 37 degrees C (prehypothermic), 13 degrees C (hypothermic) and at 30 degrees C (during rewarming). Blood pressure was also recorded. The model provides a good method to investigate the colloid osmotic changes of both plasma and interstitium during hypothermic situations.