RESUMEN
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.
Asunto(s)
Quemaduras/fisiopatología , Carbacol/farmacología , Fluidoterapia , Absorción Intestinal/efectos de los fármacos , Flujo Sanguíneo Regional/efectos de los fármacos , Animales , Quemaduras/terapia , Modelos Animales de Enfermedad , Perros , Electrólitos/farmacocinética , Electrólitos/uso terapéutico , Glucosa/farmacocinética , Glucosa/uso terapéutico , Mucosa Intestinal/irrigación sanguínea , Masculino , ResucitaciónRESUMEN
OBJECTIVE: To investigate the effect of carbachol (CAR) on gastric emptying and gastric mucosa partial pressure of carbon dioxide (PgCO2) in the resuscitation of burn shock with oral administration of glucose-electrolyte solution (GES) in dogs. METHODS: Twenty-four adult male Beagle dogs were randomly divided into 4 groups: 35% total body surface area (TBSA) III degree burn resuscitated with oral GES (35% TBSA GES, n=6), 35% TBSA III degree burn with oral GES containing 20 microg/kg of CAR (35% TBSA GES/CAR, n=6), 50% TBSA III degree burn with oral GES (50% TBSA GES, n=6) and 50% TBSA III degree burn with oral GES containing 20 microg/kg of CAR (50% TBSA GES/CAR, n=6). Dogs were subjected to 35% TBSA or 50% TBSA full-thickness flame injury respectively. Thirty minutes after burn, dogs were given GES or GES containing CAR according to Parkland formula (1/2 of 4 mlxkg(-1)x1% TBSA(-1) within 8 hours post burn, and the remaining 1/2 within next 16 hours post burn) by gavage. The gastric emptying rate, PgCO2 and intolerance symptoms were determined at 2, 4, 8 and 24 hours post burn. RESULTS: The gastric emptying rate was significantly decreased in all groups after the burn (P<0.05), and it was 51.5% at 2 hours after burn in 35% TBSA GES group and 39.2% at 4 hours after burn in 50% TBSA GES group. It was gradually ameliorated, but still much lower than pre-injury levels (both P<0.05). The gastric emptying rate in GES/CAR group were significantly higher at all time points after injury than those in 35% GES group (P<0.05), and it was higher than that in 50% GES group at 8 hours and 24 hours (both P<0.05). The gastric emptying rate restored to pre-injury levels (P>0.05) in 35% GES/CAR group, and it was still lower than pre-injury level in 50% GES/CAR group (P<0.05). The PgCO2 were significantly elevated in all groups post burn (all P<0.05), and could not return to pre-injury levels. The PgCO2 in GES/CAR group were significantly higher at all time points after injury than those in 35% GES group (P<0.05), and it was higher than that in 50% GES group at 4 hours and 24 hours (P<0.05). The degree of gastric intolerance symptoms could be ranked as follows: 50%TBSA GES group (83.3%, 5/6)>50% TBSA GES/CAR group (50.0%, 3/6)>35%TBSA GES group (16.7%, 1/6)>35%TBSA GES/CAR group (0, 0/6). CONCLUSION: The results indicate that CAR has a significant effect in improving gastric emptying and gastric ischemia during oral resuscitation of burn shock with a glucose electrolyte solution.