Recent animal studies have shown that aggressive volume replacement toward more than normotension causes a marked increase in blood loss from the site of vascular injury and produces significant mortality in animal model of near-fatal(40-50ml/kg
bleeding) uncontrolled hemorrhagic shook(UCHS). The purpose of this study was to establish near-fatal UCHS model in rat and to find the optimal level of preoperative fluid resuscitation in near-fatal UCHS. We could establish UCHS model in rat by
transsecting the terminal branch of ileocolic artery and vein. The mean survival time was 54 munutes with no fluid resuscitation. We used this UCHS model to compare the effects of resuscitation to mean arterial pressure of 60 to 80, 100mmHg.
Fourty-one
mature rats(350 to 500gm) were instrumented and subjected to intraperitoneal bleeding. Ten minutes after transsecting ileocolic vessel, normal saline infusion was begun at 10ml/100g/hr except control group(no fluid resusctation, n=12) and
continued
as
needed to maintain the following endpoints: group I (MAP=60mm Hg, n=11), group II(MAP=80mmHg, n=12), and group III(MAP=100mmHg, n=6). When mean arterial pressure was changed to ±5mmHg from each desired mean arterial pressure, normal saline
infusion was
ceased or maintained. All animals were observed for 120 minutes or unitil death. No animal survived until 120 minutes. Mean survival time was 48.9minutes, 95.8 minutes, 75.8 minutes, and 75.8 minutes for control group, group I, II, and III,
respectively. Intraperitoneal hemorrhege volume for four groups was 2.5ml/100g, 6.2ml/100g, 6.7ml/100g, and 9.8ml/100g. In setting of UCHS we conclude that maintenance of the hypotensive state (MAP=60mmHg) with normal saline infusion causes less
blood
loss and may be preferable definitive surgical repair of bleeding site.
|