Objective:To investigate the effect of aortic root repair and replacement on the surgical effect and postoperative complications of Stanford type A aortic dissection.Methods:By retrospective case-control study, 190 patients with Stanford type A aortic dissection admitted to the Affiliated Hospital of Jining Medical College from August 2020 to December 2023.According to the different surgical treatment methods, they were divided into repair group ( n=65) and replacement group ( n=125). Patients in the repair group received aortic root repair, while patients in the replacement group received aortic root replacement, that was, Bentall operation. The surgical related indexes, surgical effect, postoperative outcome and mid-term survival rate of the two groups were compared. The measurement data conforming to the normal distribution were expressed by the mean standard deviation ( ± s), and the comparison between groups adopted t-test; The measurement data of skewed distribution were expressed by M( Q1, Q3), and the comparison between groups was conducted using the rank sum test. Counting data were expressed by the number of cases and percentage (%), and the comparison between groups was conducted by chi-square test or Fisher exact probability method. Results:There was no significant difference in distal aortic operation, cardiopulmonary bypass time, hypothermic circulatory arrest time and occlusion time between repair group and replacement group ( P>0.05).There was no significant difference in ventilator-assisted time, intensive care unit stay time, visual analogue score(VAS) after waking up and hospitalization time between repair group and replacement group ( P>0.05).There was no significant difference between the two groups in 30-days mortality rate after discharge (9.2% vs 11.2%) and postoperative complications (18.5% vs 22.4%) ( P>0.05). Kaplan-Meier survival curve analysis showed that there was no significant relationship between the medium-term survival rate of patients in repair group and replacement group ( χ2=0.46, P=0.500). During the follow-up period, one patient in the replacement group underwent reoperation, including Bentall operation, with an interval of 14 months. Conclusions:the choice of aortic root repair or replacement has no effect on the surgical effect and postoperative complications of Stanford A aortic dissection patients. The short-term and medium-term survival rate of aortic root repair is similar to that of replacement, and no patient received proximal surgery again during the follow-up period, which is feasible and safe.

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.

Objective To evaluate the effect of dexmedetomidine on the efficacy of patient-controlled intravenous analgesia (PCIA) with morphine after elective radical gastrectomy. Methods One hundred and twenty ASA Ⅰ or Ⅱ patients aged 41-64 yr weighing 50-80 kg undergoing elective radical gastrectomy were randomly divided into 2 groups of 60 patients, according to the composition of PCIA solution:group I morphine (group M)and group Ⅱ morphine + dexmedetomidine (group MD). In group M the PCIA solution contained morphine 100 mg in 200 ml of normal saline (NS), while in group MD the PCIA solution contained morphine 100 mg+dexmedetomidine 200 μg in NS 200 ml. PCIA was started immediately after operation. A loading dose of 6 ml was given iv at the end of operation. PCIA setting was as follows:background infusion 1 ml/h, bolus dose 3 ml and lockout interval 10 min. VAS score was maintained at ≤4 and Ramsay score at 2-3. The total amount of morphine consumed, the number of attempts and successfully delivered doses within 24 and 48 h after operation were recorded. Postoperative complications including nausea, vomiting, bradycardia, hypotension, oversedation and respiratory depression were recorded. Results The total amount of morphine consumed, the number of attempts and successfully delivered doses within 24 and 48 h after operation were significantly smaller and the incidence of nausea and vomiting and pruritus was significantly lower in group MD than in Sroup M. No bradycardia,hypotension, oversedation or respiratory depression was observed in either group. Conclusion Dexmedetomidine added to intravenous morphine PCA can improve the analgesic efficacy after radical gastrectomy with less adverse effects.

Objective To investigate the dose-respeuse relationship of levobupivacaine for spinal anesthesia in patients undergoing cesarean section.Methods Sixty ASA Ⅰ or Ⅱ patients aged 25-35 yr weighing 60-90 kg scheduled for elective cesarean section under spinal anesthesia were enrolled in this study.Spinal puncture was performed at the L3,4 interspace.A 25 G spinal needle was inserted into the subarachnoid space cephalad.The patients were randomized to receive levobupivacaine 7.5 mg (group L1 ),10 mg (group L2),12.5 mg (group L3) or 15 mg (group L4) diluted to 3 ml with 5% glucose over 30 s (n = 15 each).The degree of pain was evaluated at the time of skin incision using visual analogue scales (VAS) (0 = no pain and 10 = worse pain ever).Effective analgesia was defined as VAS = 0.Spinal analgesia was inadequate when VAS≥1 and then 1% lidocaine 5-10 ml was given epidurally.The doses of levobupivacaine for effective analgesia in 50% and 95% of patients ( ED50 and ED95 ) and 95 % confidence interval were calculated by Probit method.Results The ED50 of levobupivacaine was 9.0 mg (95% confidence interval 7.8-9.9 mg) and ED95 13.2 mg (95% confidence interval 11.6-17.6 mg) for spinal anesthesia.Conclusion The ED50 and ED95 of levobupivacaine for spinal anesthesia in patients undergoing cesarean section are 9.0 mg and 13.2 mg respectively.