Objective To evaluate the accuracy of ultrasound-measured inferior vena cava (IVC) diameter in assessment of the preoperative blood volume in elderly patients.Methods Sixty patients,aged 60-75 yr,with body mass index 20-25 kg/m2,of ASA physical status Ⅰ-Ⅲ,scheduled for elective transurethral resection of prostate,were randomly divided into 3 groups (n =20 each):control group (group C),lactated Ringer's solution group (group RL),and hydroxyethyl starch group (group H).Lactated Ringer's solution 8 ml/kg was infused intravenously in group RL.Hydroxyethyl starch 130/0.4 8 ml/kg was infused intravenously in group H.SpO2,mean arterial pressure (MAP),HR and central venous pressure (CVP) were monitored before and after fluid therapy.The IVC diameters,both during expiration (IVCe) and inspiration (IVCi),were measured using ultrasound.IVC collapsibility index (IVC-CI) was calculated.Results The IVCeand IVCi were significantly increased,and IVC-CI was decreased after fluid therapy as compared with those before fluid therapy in RL and H groups.Compared with group C,the IVCe and IVCi were significantly increased,and IVC-CI was decreased after fluid therapy in RL and H groups.IVCe and IVCi were positively correlatedwith CVP (r=0.746 and 0.697,respectively).IVC-CI was negatively correlated with CVP (r =-0.547).Conclusion Ultrasoundmeasured IVC diameter provides better accuracy in assessing the preoperative blood volume in elderly patients.

ObjectiveTo investigate the role of phosphatidylinositol 3-kinase/protein-serine-threonine kinases (PI3K-Akt) signal pathway in the protection of myocardium against ischemia-reperfusion (I/R) injury by diasoxide postconditioning in rats.MethodsThirty-six male SD rats weighing 250-300 g were randomly divided into 4 groups using random number table (n =9 each):group I/R; group diazoxide (group D); group wortmannin (PI3K inhibitor) (group W) and group wortmannin + diazoxide (group WD).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 4 ml/kg,intubated and mechanically ventilated.Myocardial I/R was produced by 30 min occlusion of left anterior descending coronary artery followed by 120 min reperfusion.0.1％ dimethyl sulfoxide (the vehicle for diazoxide and wortmannin)/diazoxide at 0.47 mg· kg-1 · min-1/wortmannin at 1 μg·kg-1 ·min-1 was infused for 15 min starting from 25 min of ischemia in groups I/R,D and W respectively.In group DW wortmannin was infused at 5 min before diazoxide infusion.Blood samples were collected from left ventricle at the end of 120 min reperfusion for measurement of lactate dehydrogenase (LDH) activity.Myocardial infarct size was measured.Myocardial specimens were obtained for determination of apoptosis index (the number of apoptotic cells/the total number of cells examined) and expression of Bcl-2 and Bax.Bcl-2/Bax ratio was calculated.ResultsDiazoxide postconditioning significantly decreased plasma LDH activity,myocardial infarct size,apoptosis index and Bax expression in myocardium and increased myocardial Bcl-2 expression and Bcl-2/Bax ratio in group D compared with group I/R.Wortmannin partly counteracted the protective effects of diazoxide postconditioning against myocardial infarct.There was no significant difference in the above variables between groups I/R and W.ConclusionPI3K-Akt signal pathway is involved in the protective effects of diazoxide postconditioning on myocardium against I/R injury.