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Objective:To evaluate the effect of paravertebral nerve block (PVNB) combined with general anesthesia on intraoperative regional cerebral oxygen saturation (rScO 2) in elderly patients undergoing thoracoscopic lobectomy. Methods:Seventy American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes, aged 60-85 yr, with body mass index of 18-25 kg/m 2, were divided into 2 groups ( n=35 each) using a random number table method: general anesthesia group (group G) and PVNB combined with general anesthesia group (group PG). PVNB was performed at T 4 and T 6 with 0.5% ropivocaine 10 ml for each site under ultrasound guidance before induction of anesthesia in group PG.After induction of anesthesia, anesthesia was maintained with IV propofol and remifentanil, and a patient-controlled intravenous analgesia pump was connected at the end of operation.The maximum and minimum rScO 2 and cumulative time of rScO 2 below the baseline value were recorded.The rScO 2 was recorded before anesthesia (T 0), at 5 min before one-lung ventilation (T 1), at 5 min after one-lung ventilation (T 2) and at tracheal extubation (T 3). The length of postoperative hospital stay and complications within 30 days after operation were recorded. Results:Compared with group G, the minimum rScO 2 and rScO 2 at T 2 and T 3 were significantly increased, the incidence of postoperative cognitive dysfunction was reduced ( P<0.05), and no significant change was found in the other parameters mentioned above in group PG ( P>0.05). Conclusion:PVNB combined with general anesthesia can improve intraoperative rScO 2 and reduce the development of postoperative cognitive dysfunction in elderly patients undergoing thoracoscopic lobectomy.
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Objective:To identify the risk factors for decrease in regional cerebral oxygen saturation (rScO 2) during one-lung ventilation (OLV) in the patients undergoing thoracic surgery. Methods:A total of 175 patients of both sexes, aged ≥55 yr, with expected operation time≥2 h, scheduled for elective thoracic surgery with OLV, were selected in the Fourth Hospital of Hebei Medical University from August 2017 to September 2018.The rScO 2 was continuously monitored from the beginning of anesthesia induction until removal of tracheal intubation.General anesthesia, general anesthesia combined with epidural block or general anesthesia combined with local nerve block were used.The baseline characteristics, previous medical history and history of anesthesia surgery, type of surgery, method of anesthesia, duration of anesthesia, duration of OLV, duration of surgery, and intraoperative adverse events (hypoxemia, hypotension, bradycardia, etc.) were recorded.According to whether a decrease in rScO 2 occurred during OLV (absolute value of rScO 2 was less than 65% or a decrease of more than 20% of the baseline value), the patients were divided into 2 groups: low rScO 2 group and normal rScO 2 group.Multivariate logistic regression analysis was used to identify the risk factors for decrease in rScO 2 during OLV. Results:One hundred and seven patients developed decrease in rScO 2 during OLV, with an incidence of 61.1%.The results of logistic regression analysis showed that hypoxemia was an independent risk factor for decrease in rScO 2, and general anesthesia combined with epidural block was a protective factor for decrease in rScO 2 during OLV. Conclusion:Hypoxemia is an independent risk factor for decrease in rScO 2 during OLV, while general anesthesia combined with epidural block is a protective factor for decrease in rScO 2 in the patients undergoing thoracic surgery.
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Objective To study the distribution of the regions of ultrasound-guided erector spinae plane block (ESPB) at the level of T5 transverse process.Methods Thirty male patients,aged 18-64 yr,with body mass index of 18-24 kg/m2,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective thoracotomy,were enrolled in this study.ESPB was conducted with 0.5％ ropivacaine hydrochloride 0.4 ml/kg at the level of T5 transverse process under ultrasound guidance before induction of general anesthesia.Blocks in each thorax and back region (the left side of the body was divided into 18 different regions based on the anatomical "landmarks" on the body surface,No.1-18) were assessed by cold stimulation.Effective block in each region was recorded at 10,15,20,25,30,40 and 50 min after administration.The adverse reactions such as pneumothorax,puncture hematoma and local anesthetic intoxication were recorded.Results The blocking range was basically fixed at 30 min after a single ESPB injection at the level of T5 transverse process,and the regions covered from the sternal angle to the level of the rib arch.The regions of effective block were No.1-3 and 5-7 in ≥95％ patients,and the regions of effective block were No.1-15 and 17 in patients ≥90％ and ＜ 95％.No patients developed adverse reactions such as pneumothorax,puncture hematoma or local anesthetic intoxication.Conclusion The regions of effective ultrasound-guided ESPB at the level of T5 transverse process are mainly distributed in T2-T8 thoracodorsal skin areas.
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Objective To evaluate the role of mitochondrial ATP-sensitive potassium(mito-KATP) channels in dexmedetomidine-induced attenuation of myocardial ischemia-reperfusion(I∕R)injury in rats. Methods Forty pathogen-free healthy male Sprague-Dawley rats, aged 8-12 weeks, weighing 200-350 g, were divided into 5 groups(n=8 each)using a random number table: sham operation group(group S), I∕R group, dexmedetomidine group(group DEX), a specific mito-KATPchannel blocker 5-hydroxyde-canoate(5-HD)group(group 5-HD)and dexmedetomidine plus 5-HD group(group DEX+5-HD). Myo-cardial I∕R was produced by occlusion of the anterior descending branch of the left coronary artery for 30 min followed by 120 min reperfusion in pentobarbital sodium-anesthetized rats. Dexmedetomidine 5 μg∕kg was intraperitoneally injected at 15 min prior to reperfusion in group DEX.5-HD 40 mg∕kg was intraperitoneally injected at 30 min prior to reperfusion in group 5-HD. In group DEX+5-HD, 5-HD 40 mg∕kg and dexme-detomidine 5 μg∕kg were intraperitoneally injected at 30 and 15 min prior to reperfusion, respectively. The parameters of cardiac function such as left ventricular systolic pressure(LVSP), left ventricular end-dias-tolic pressure(LVEDP)and the maximum rate of increase or decrease in left ventricular pressure(±dp∕dtmax)were recorded before ischemia(T0)and at 60 and 120 min of reperfusion(T1,2). Blood samples were collected from the carotid artery at the end of reperfusion for determination of the concentrations of cre-atine kinase-MB(CK-MB)and cardiac troponin I(cTnI)in serum. The animals were then sacrificed, and hearts were removed for determination of the myocardial infarct size in the left ventricular myocardial tissues. Results Compared with group S, the LVSP and ±dp∕dtmaxwere significantly decreased, and the LVEDP was increased at T1-2, and the concentrations of CK-MB and cTnI in serum and myocardial infarct size were increased in the other groups(P<0.05). Compared with group I∕R, the LVSP and ±dp∕dtmaxwere signifi-cantly increased, and the LVEDP was decreased at T1-2, and the concentrations of CK-MB and cTnI in ser-um and myocardial infarct size were decreased in group DEX, and the LVSP and ±dp∕dtmaxwere significant-ly increased at T1-2, the concentrations of CK-MB and cTnI in serum and myocardial infarct size were de-creased(P<0.05), and no significant change was found in LVEDP in group DEX+5-HD, and no signifi-cont change was found in the parameters mentioned above in group 5-HD(P>0.05). Compared with group DEX, the LVSP and ±dp∕dtmaxwere significantly decreased, and the LVEDP was increased at T1-2, and the concentrations of CK-MB and cTnI in serum and myocardial infarct size were increased in DEX+5-HD group(P<0.05). Conclusion The mechanism by which dexmedetomidine attenuates myocardial I∕R inju-ry is partially related to promotion of mito-KATPchannel opening in rats.
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Objective To determine the optimal dose of oxycodone for patient-controlled intravenous analgesia (PCIA) after gastrointestinal surgery when combined with dexmedetomidine in elderly patients.Methods Sixty patients of both sexes,aged 65-80 yr,weighing 50-75 kg,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,undergoing elective open gastrointestinal surgery,were divided into 3 different doses of oxycodone groups (group O1,group O2 and group O3,n=20 each) using a random number table.At 15 min before the end of surgery,oxycodone 0.1 mg/kg was intravenously injected,and PCIA pump was connected simultaneously.In O1,O2 and O3 groups,the PCIA solution contained dexmedetomidine 2.0 μg/kg and oxycodone 0.3,0.5 and 0.7 mg/kg in 100 ml of 0.9％ normal saline,respectively.The PCIA pump was set up to deliver a 0.5 ml bolus dose with a 15-min lockout interval and background infusion at 2 ml/h.Oxycodone 0.05 mg/kg was intravenously injected as a rescue analgesic after surgery,postoperative pain was assessed using a verbal rating scale,and the verbal rating scale score was maintained ≤4.The number of successfully delivered doses and requirement for rescue analgesics were recorded within 48 h after surgery,and the rate of rescue analgesia was calculated.The occurrence of adverse reactions such as nausea,vomiting,dizziness,respiratory depression,somnolence,bradycardia,hypotension and over-sedation was recorded.Patients' satisfaction with analgesia at postoperative 72 h and the length of postoperative hospital stay were also recorded.Results Compared with group O1,the rate of rescue analgesia after surgery and the number of successfully delivered doses were significantly decreased,and the degree of patients' satisfaction with analgesia was increased in O2 and O3 groups,and the incidence of nausea and somnolence was significantly increased in group O3 (P＜0.05).Compared with group O2,no significant change was found in the rate of rescue analgesia after surgery or the number of successfully delivered doses (P＞0.05),and the incidence of nausea and somnolence was increased in group O3 (P＜0.05).Conclusion When combined with dexmedetomidine 2.0 μg/kg,the optimal dose of oxycodone for PCIA is 0.5 mg/kg after gastrointestinal surgery in elderly patients.
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Objective:To investigate the effects of dexmedetomidine on perioperative cardiac adverse events in elderly patients with coronary heart disease.Methods:Sixty elderly patients,who were diagnosed as coronary heart disease and underwent gastric cancer operation,were randomly divided into 2 groups (n=30):the dexmedetomidine group (Dex group) and the control group.In the Dex group,dexmedetomidine was administered intravenously at 0.5 μtg/(kg.h) after a bolus infusion at 0.5 μg/kg for 10 min before anesthesia induction.In the control group,equal volume of normal saline was infused instead of dexmedetomidine.The 2 groups received the same anesthesia treatment.The venous bloods were collected at the preoperative 0 h and postoperative 24 h.The concentrations of cardiac troponin (cTnⅠ),N-terminal pro-brain natriuretic peptide (NT-proBNP) and hypersensitive C-reactive protein (hs-CRP) were determined.The ECG was monitored at the above time and the postoperative incidence of cardiac adverse events was recorded.Results:The levels of cTnⅠ,NT-proBNP and hs-CRP in serum were elevated in the 2 groups after the operation.Compared with the control group,the levels of cTnⅠ,NT-proBNP and hs-CRP were significantly decreased in the Dex group (P＜0.05).Compared with the control group,the incidence ofbradycardia were significantly increased,while the myocardial ischemia and tachycardia were significantly decreased in the Dex group during the operation (P＜0.05);the incidence of silent myocardial ischemia and arrhythmia was significantly reduced at 3 days after operation in the Dex group (P＜0.05).Conclusion:Dexmedetomidine could decrease the incidence of cardiac adverse events in elderly patients with coronary heart disease.
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Objective To compare the postoperative analgesic effect of the single dose of oxycodone and dezocine in patients who underwent gynecological laparoscopic operation. Methods Sixty patients who underwent elective gynecological laparoscopic operation were randomly divided into two groups (n=30): oxycodone group (group O) and dezocine group (group D). Fifteen minutes before the end of surgery, oxycodone 0.1 mg/kg was given in O group, and dezocine 5 mg was given to D group. Twenty minutes before the end of surgery, tropisetron 5 mg was given to both groups. Analgesia was maintained by propofol-remifentanil with TCI. The mean arterial pressure (MAP) and heart rate (HR) of T1, T2, T3 and T4 were recorded respectively in both two groups. After the operation, pain of visual analogue scale (VAS) was assessed in 2 h ,4 h , 6 h and 24 h, respectively. Results There were no significant differences in MAP and HR between two groups at T1, T2, T3 and T4 (P＞0.05). The VAS score was significantly lower in group O than that of group D (P＜0.05). There was significant difference in the incidence of nausea between the two groups (P＜0.05). Conclusion Single dose of oxycodone 0.1 mg/kg can be used for postoperative analgesia after gynecological laparoscopic operation, and which has better analgesia than that of dezocine, except for the adverse reaction of nausea.
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Objective To evaluate the effect of obesity on the potency of propofol for sedation.Methods Sixty patients of both sexes, aged 35-55 yr, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ , scheduled for elective operation under general anesthesia, were enrolled in the study.The patients were divided into 2 groups (n=30 each) according to the body mass index (BMI) : normal body weight (BMI ＜ 25 kg/m2) group (group C) and obesity (BMI 30-40 kg/m2) group (group O).No patients received premedication.Propofol was given by target-controlled infusion.The initial target plasma concentration of propofol was set at 1.2 μg/ml.After the target concentration was steadily maintained for 30 s, it was increased in 0.3 μg/ml increment until the patients lost consciousness (OAA/S score =1).The target plasma concentration of propofol was recorded during each period.The median effective concentration (EC50) and 95％ confidence interval of propofol for loss of consciousness was calculated using probit analysis.Results The EC50 and 95％ confidence interval of propofol for loss of consciousness were 3.82 (3.73-3.90) and 3.29 (3.20-3.37) μg/ml in group C and group O, respectively.Compared with group C, the EC50 was significantly decreased in group O (P＜0.05).Conclusion Obesity can enhance the potency of propofol for sedation.
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Objective To investigate the effect of volume therapy with 6％ hydroxyethyl starch (HES) 130/0.4 on mesenteric microcirculation in a rabbit model of hypovolemia.Methods Sixty-four adult male rabbits,weighing 2.0-2.3 kg,were randomly divided into 4 groups( n =16 each):control group (group C),hypovolemia group (group HM),Ringer's solution group (group RS) and 6％ HES 130/0.4 group (group HES).The animals were anesthetized with sodiun pentobarbital 3.0-3.5 mg/kg.Femoral artery,femoral vein and right internal jugular vein were cannulated for MAP monitoring,blood withdrawing and fluid adminstration.Hypovolemia was induced by withdrawing blood from femoral vein of 30％ blood volume in 30 min in groups HM,RS and HES.In group C,no blood was withdrawed.In group RS,Ringer's solution 3 times of the volume of blood withdrawn was infused,while 6％ HES 130/0.4 equal volume of blood withdrawn was infused via right internal jugular vein immediately at the end of blood withdrawing.MAP and HR were recorded and femoral artery and femoral vein blood samples were taken before blood withdrawing (T0),immediately at the end of blood withdrawing(T1 ),immediately at the end of volume therapy(T2 ) and 30 min after volume therapy(T3 ).DO2,VO2 and ERO2 were calculated.Diameter and blood flow speed of microvessel were determined.Results Compared with group C,HR was significantly increased,MAP decreased,diameter and blood flow speed of microvessel were decreased at T1～3,DO2 was increased at T1 in group HM.Compared with group HM,MAP was significantly increased at T2,HR decreased at T2,3,DO2and VO2 were increased at T1～3,diameter of arteriole was increased at T2 whlie decreased at T3,diameter of veinule and blood flow speed of microvessel were increased at T2,3 in group RS,MAP was significantly increased at T2,HR was decreased whlie DO2 and VO2 were decreased,VO2,ERO2,diameter and blood flow speed of microvessel were increased at T2,3 in group HES.Compared with group RS,DO2,VO2 and ERO2 were significantly decreased at T3 in group HES.Conclusion Volume therapy with 6％ HES 130/0.4 can improve mesenteric microcirculation,organ perfusion and oxygen metabolic in a rabbit model of hypovolemia.
