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Objective To evaluate the effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic ischemia?reperfusion(I∕R)in rats. Methods Healthy male Wistar rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups(n=16 each)using a random number table: sham operation group(Sham group), hepatic I∕R group(I∕R group)and limb ischemic preconditioning group(LIP group). In LIP group, the lower limb blood flow was blocked for 10 min with an elastic rubber tourniquet at the right groin followed by 30?min reperfusion through releasing the tourni?quet. Hepatic I∕R injury was induced by occlusion of the portal vein, hepatic artery and common bile duct for 30 min followed by reperfusion in I∕R and LIP groups. Eight rats in each group were selected at 6 h of reperfusion and samples from the cardiac apex were taken for determination of plasma concentrations of tumor necrosis factor?alpha(TNF?α)and interleukin?10(IL?10)by radioimmunoassay. Then the rats were sacrificed and the small intestine tissues and brain tissues were removed. Intestinal damage was as?sessed and scored according to Chiu. The activity of myeloperoxidase(MPO)in intestinal mucosa was de?tected by colorimetric method. The pathological changes of brain tissues were examined under a light micro?scope. The ultrastructure of brain tissues was observed under an electron microscope. Eight rats in each group were randomly selected at 6 h of reperfusion, and Evans blue(EB)2 mg∕kg was injected through the caudal vein over 1 min. Then the rats were sacrificed, brain tissues were removed for measurement of EB content, and the brain water content was calculated. Results Compared with Sham group, Chiu′s score and MPO activity in intestinal tissues were significantly increased, the brain water content and EB content were increased, and the concentrations of TNF?α and IL?10 in plasma were increased in I∕R group and LIP group(P <0.05). Compared with I∕R group, Chiu′s score and MPO activity in intestinal tissues were significantly decreased, the brain water content and EB content were decreased, and plasma IL?10 concentrations were increased(P <0.05), no significant change was found in plasma TNF?α concentra?tions(P>0.05), and the pathological changes of brain tissues were significantly attenuated in LIP group. Conclusion Limb ischemic preconditioning can attenuate intestinal injury and brain injury induced by he?patic I∕R, and the mechanism may be related to inhibiting systemic inflammatory responses of rats.
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Objective To compare the baroreflex sensitivity (BRS) when controlled hypotension was performed with sevoflurane versus isoflurane in the pediatric patients.Methods Sixty male American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients,aged 3-16 yr,with body mass index of 20-28 kg/m2,scheduled for elective scoliosis surgery under general anesthesia,were randomly divided into 2 groups (n=30 each) using a random number table:sevoflurane-induced hypotension group (group Sev) and isoflurane-induced hypotension group (group Iso).Anesthesia was induced with midazolam,sufentanil and propofol.Endotracheal intubation was facilitated with rocuronium.Anesthesia was maintained with closed-circuit low flow anesthesia with either sevoflurane or isoflurane,maintaining mean arterial pressure at 55-65 mmHg and bispectral index values at 40-60 during surgery.Cardiovascular BRS was measured before induction of anesthesia (T0),immediately after intubation (T1),immediately after the end-tidal inhalational anesthetic concentration reached 1 minimal alveolar concentration (T2),and at 10,20 and 30 min after target hypotension (mean arterial pressure 55-65 mmHg) was achieved (T3-5).Results There was no significant difference in BRS at T0-2 between the two groups (P＞0.05).Compared with the value at To,the BRS was significantly decreased at the other time points in the two groups (P＜0.05).Compared with the value at T1,the BRS was significantly increased at T2,and decreased at T3-5 in the two groups (P＜0.05).The BRS was significantly lower at T3-5 than at T2 in the two groups (P＜0.05).The BRS was significantly lower at T3-5 in group Sev than in group Iso in the two groups (P＜0.05).Conclusion Sevoflurane produces better efficacy than isoflurane when used for controlled hypotension in the pediatric patients.