卡巴胆碱对烧伤犬肠内补液时肠黏膜血流量和吸收效率的影响

目的 研究卡巴胆碱对50%总体表面积(TBSA)Ⅲ度烧伤休克Beagle犬肠内补液时肠黏膜血流量和吸收效率的影响.方法 成年雄性Beagle犬18只,采用凝固汽油燃烧法造成约(51.2±2.6)%TBSAⅢ度烧伤,伤后0.5 h开始按Parkland公式量和速率补液.随机将动物均分为静脉输葡萄糖一电解质液(GES)组(VGES)、肠内输GES组(EGES)和肠内输GES/卡巴胆碱组(EGES/CAR,含0.25 μg/kg卡巴胆碱的GES).在动物清醒状态下观察两个肠内补液组伤后8 h内小肠黏膜血流量(IBF)、水和Na+的吸收速率,以及3组动物血浆Na+浓度、血浆容量(PV)和伤后8 h小肠组织Na+-K+-ATP酶活性的变化.结果 伤后两个肠内补液组水和Na+的吸收速率均较伤前显著降低(P均＜0.05),EGES/CAR组自伤后1.5 h和2.5 h起显著高于EGES组(P均＜0.05),但8 h两组均低于伤前和按Parkland公式补液速率(P＜0.05).EGES组对肠内补液不耐受(腹泻)发生率为83%,显著高于EGES/CAR组的50%.伤后8 h EGES/CAR和EGES组输入肠内的液体仅有47.1%和63.8%被吸收;EGES/CAR组吸收液体总量和吸收率显著多于EGES组.伤后各组IBF均较伤前显著降低;伤后8 h已恢复到伤前水平(P＞0.05);EGES/CAR组IBF伤后2 h起高于EGES组(P＜0.05),但两个肠内补液组伤后8 h仍显著低于伤前和VGES组水平(P均＜0.05).3组伤后8 h小肠黏膜Na+-K+-ATP酶活性比较:VGES组＞EGES/CAR组＞EGES组(P＜0.05).两个肠内补液组伤后8 h内的血浆Na+浓度和PV均显著低于VGES组(P均＜0.05),但伤后4 h起EGES/CAR组显著高于EGES组(P均＜0.05).结论 50%TBSAⅢ度烧伤早期IBF和Na+-K+-ATP酶活性显著降低,肠内补液的吸收效率显著低于按Parkland公式输入速率,不能维持静脉补液的血浆Na+浓度和PV;而卡巴胆碱能增加IBF和Na+-K+-ATP酶活性,提高肠内补液的吸收速率、PV和血浆Na+浓度,改善口服补液的疗效.

Effect of carbachol on intestinal mucosa blood flow and absorption rate of glucose-electrolyte solution during enteral resuscitation for 50%total body surface area full-thickness burn injury in dog

OBJECTIVE: To investigate the effect of carbachol (CAR) on blood flow of intestinal mucosa and absorption rate of glucose-electrolyte solution (GES) during enteral resuscitation of burn shock in dog. METHODS: Eighteen male Beagle dogs were subjected to a (51.2+/-2.6)% total body surface area (TBSA) full-thickness flame injury, and fluid resuscitation was given according to Parkland formula 0.5 hour after burn. Animals were randomly divided into intravenous infusion of GES group (VGES group, n=6), enteral infusion of GES group (EGES group, n=6) and EGES containing 0.25 microg/kg of CAR group (EGES/CAR group n=6). In the first 8 hours post burn, intestinal absorption rate of water and Na+, intestinal mucosa blood flow (IBF), the plasma volume (PV) and plasma concentration of Na+ were continuously determined without anesthesia. At the end of 8 hours animals were sacrificed, and specimens of gut tissue were taken to determine the activity of Na+-K+-ATPase. RESULTS: The intestinal absorption rate of water and Na+ was reduced markedly after burn in two enteral resuscitation groups and much lower than pre-injury levels and the expected infusing rate according to Parkland formula. It was found that the absorption rate of water and Na+ from 1.5 hours and 2.5 hours in EGES/CAR group were significantly higher compared with those in EGES group (all P<0.05). During 8 hours after burn, only 47.1% and 63.8% of fluids enterally infused in EGES and EGES/CAR groups were absorbed by the gut. The volume of fluid absorbed and the fluid absorption rate were significantly higher in EGES/CAR group than those in EGES group (P<0.05). Incidence of gut intolerance (diarrhea) was 83% in EGES group, which was higher than that of in EGES/CAR group (50%). IBF was significantly decreased compared with pre-injury levels in all groups. Enteral infusion of CAR led to a significant elevation of IBF in EGES/CAR compared with GES group from 4 hours after burn, but it was still lower than pre-injury levels and those in VGES group. The Na+-K+-ATPase activity between three groups ranked as follows: VGES group>EGES/CAR group>EGES group (P<0.05). Within 8 hours post injury, PV and plasma concentration of Na+ in two enteral resuscitation groups were much lower than those in VGES group, but from 4 hours after burn the values in EGES/CAR group were higher than those in EGES group (all P<0.05). CONCLUSION: 50%TBSA full-thickness flame injury led to a markedly decrease in intestinal absorption rate of water and Na+. The total volume of fluid absorbed by intestine in 8 hours was significantly lower in enteral resuscitation groups compared to the regime of the Parkland formula. CAR promoted intestinal absorption rate and PV by increasing the intestinal blood flow and Na+-K+-ATPase activity, and it seems to exert a helpful effect on the resuscitation of burn shock with electrolyte solution per oral route.