Objective To evaluate the effect of inverse ratio ventilation (I ∶ E =1 ∶ 1) on ventilatory function during pneumoperitoneum in the obese patients undergoing laparoscopic surgery.Methods Sixty patients,aged 30-64 yr,of ASA physical status Ⅰ or Ⅱ],with body mass index of 30-40 kg/m2,scheduled for elective laparoscopic radical resection of rectal carcinoma,were divided into 2 groups (n =30 each) using a random number table:I∶E =1∶1 mode of ventilation after pneumoperitoneum (group A),and I∶E =1∶2 mode of ventilation after pneumoperitoneum (group B).Anesthesia was induced with midazolam,fentanyl,propofol and vecuronium.The patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with infusion of propofol and remifentanil,sevoflurane inhalation,and intermittent iv boluses of vecuronium.In group A,the patients received I ∶ E =1 ∶ 1 after pneumoperitoneum.In group B,the patients received I ∶ E =1 ∶ 2.PaO2,PaCO2,peak inspiratory pressure (PIP),mean airway pressure (Pmean),dynamic compliance (Cdyn),intrapulmonary shunt (Qs/Qt),PETCO2,RR,MAP and HR were recorded immediately after intubation,and at 30,60 and 120 min of pneumoperitoneum.Results Compared with group B,PaO2,Pmean and Cdyn were significantly increased,and PIP and Qs/Qt were decreased,and no significant changes were found in RR,PET CO2,PaCO2 and hemodynamic parameters in group A.Conclusion Inverse ratio ventilation (I ∶ E =1 ∶ 1) can effectively improve ventilatory function during pneumoperitoneum in the obese patients undergoing laparoscopic surgery without exerting adverse effects on hemodynamics.

Objective To explore the effect of different type of atrial fibrillation(AF) on plasma brain natriuretic peptide(BNP) level in male patients.Methods Fifty-eight hospitalized male patients with AF were enrolled,including 35 cases with paroxysmal AF,14 cases with persistent AF,and 9 cases with permanent AF.All subjects had the examination of echocardiography/electrocardiogram within 24 h after admission.Venous blood sample were collected in a quiet prostration state on the next early morning for BNP detection.The plasma BNP level was determined by radioimmunology-assay(RIA).Results The average level of plasma BNP in male patients with permanent AF(2343.25 ± 820.24)μg/L was significantly higher than those with persistent AF([576.43 ± 223.07]μg/L,t=8.74,P＜0.001) and paroxysmal AF([632.74 ± 103.93]μg/L,t=8.73,P＜0.001),but there was no significant difference between the last two groups(t=0.59,P＞0.05).Conclusion BNP is a sensitive indicator of early heart function impairment related with AF,particularly elevates in male patients with permanent AF.

Objective To investigate the influence of different head and neck positions on airway sealing pressure (OLP) with i-gel laryngeal mask airway (LMA) in patients undergoing elective surgery under general anesthesia with mechanical ventilation.Methods Thirty ASA Ⅰ or Ⅱ patients of both sexes aged 32-64 yr with a body mass index of 18-30 kg/m2 undergoing elective surgery under general anesthesia with LMA were studied.Size 4 i-gel LMA was placed blindly after induction of anesthesia and connected to anesthetic circuit.The criteria for successful placement were easy inflation with small leak,peak inspiratory pressure (PPeak) within normal range and normal PETCO2 wave form.Fiberoptic bronchoscopy was performed to check the position of LMA.OLP,expiratory tidal volume ( VTE ),PPeak and efficiency of mechanical ventilation were measured in different head and neck positions.OLP was measured by gradually increasing airway pressure until PPeak was reached.The measurement was stopped when there was large leak or OLP ＞ 35 cm H2 O.The efficacy of ventilation was evaluated by manually inflating the lungs (perfect:easy inflation,no audible leak; satisfactory:easy inflation,small leak; poor:difficult inflation,large leak).Results Flexion of the head significantly increased OLP and PPeak and decreased VTE,while hyperextension significantly decreased OLP and PPeak and increased VTE as compared with middle position of the head.Lung ventilation was less satisfactory when the head was flexed.Turning the head to either side did not affect ventilation.Conclusion Flexion of the head should be avoided when i-gel LMA is used during anesthesia.

Objective To evaluate the effects of propofol and sevoflurane anesthesia on cognitive function and amyloid beta protein ( Aβ) deposition in hippocampi of aged mice. Methods Thirty?six SAMP8 mice, aged 6 months, weighing 29-32 g, were randomly assigned into 4 groups ( n=9 each) using a random number table: control group ( group C ) , propofol anesthesia group ( group P ) , sevoflurane anesthesia group (group S) and propofol plus sevoflurane anesthesia group (group PS). In group P, propofol 140 mg∕kg was injected intraperitoneally, when righting reflex occurred, additional propofol 70 mg∕kg was given, and when it occurred again, additional propofol 40 mg∕kg was given. Group S continuously inhaled 1% sevoflurane for 120 min. Group PS continuously inhaled 2% sevoflurane for 120 min, and when righting reflex occurred, additional propofol 40 mg∕kg was given. Anesthesia was maintained for 120 min in P, S and PS groups. Before anesthesia and at 7, 14 and 28 days after anesthesia, Morris water maze test was performed, and the escape latency was recorded. Hippocampi were obtained to determine the expression of Aβ using immuno?histochemistry. Results Compared with group C, the escape latency was significantly prolonged at 7 days after anesthesia, and the expression of Aβwas up?regulated at 7, 14 and 28 days after anesthesia in group S, and no significant change was found in the parameters mentioned above in P and PS groups. Compared with the value at 7 days after anesthesia, the expression of Aβ was significantly down?regulated at 14 and 28 days after anesthesia in group S, and no significant change was found in the expression of Aβ at 14 and 28 days after anesthesia in C, P and PS groups. Conclusion Although sevoflurane anesthesia promotes Aβ deposition in hippocampi, it only causes short?term cognitive dysfunction, however, anesthesia with propofol or with propofol in combination with sevoflurane produces no influence in aged mice.

Objective To evaluate the role of histone methylation in the spinal cord in maintenance of neuropathic pain (NP) in rats.Methods Sixty healthy male Wistar rats, weighing 200-250 g, aged 6-8 weeks, were randomly divided into 5 groups (n =12 each) using a random number table: control group (C group), sham operation group (S group), NP group, chaetocin group (CH group), and dimethyl sulfoxide (DMSO) group.NP was induced by chronic constriction injury (CCI) to the sciatic nerve in NP, CH and DMSO groups.The sciatic nerve was only exposed in group S.H3K9 methylation methyltransferase inhibitor chaetocin 50 μg was injected intrathecally in group CH, and the equal volume of DMSO was given instead in group DMSO for 4 consecutive days, starting from 2nd day after CCI.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured before CCI (T0),before administration on 2nd day after CCI (T1), and at 5, 7, 9 and 14 days after CCI (T2-5).Six rats in each group were sacrificed after measurement of pain threshold at T3 and T5, and the lumbar segment of the spinal cord was removed for detection of the methylated H3K9 expression by immunohistochemistry.Results Compared with C group, no significant change was found in the MWT, TWL and methylated H3K9 expressionat each time point in S group (P＞0.05) , the MWT was significantly decreased, and the TWL was shortened at T1-5, and the methylated H3K9 expression was up-regulated at T3 and T5 in NP and DMSO groups, and the MWT was significantly decreased, and the TWL was shortened at T1 in CH group (P＜ 0.05).Compared with NP group, the MWT was significantly increased, and the TWL was prolonged at T2-5, and the methylated H3K9 expression was down-regulated at T3 and T5 in CH group (P＜0.05) , and no significant change was found in the MWT, TWL and methylated H3K9 expression at each time point in DMSO group (P＞0.05).Conclusion Histone methylation in the spinal cord is involved in the maintenance of NP in rats.

Objective To evaluate the effect of fentanyl on the efficacy of low-dose ropivacaine for spinal anesthesia in patients undergoing anorectal surgery.Methods Forty ASA Ⅰ or Ⅱ patients,aged 20-55 yr,with body mass index 18-28 kg/m2,scheduled for anorectal surgery,were randomly divided into 2 groups (n =20 each):0.5％ ropivacaine 7.5 mg group (group R) and 0.3％ ropivacaine 6.0 mg+ fentanyl 10 μg group (group RF).A catheter was implanted into the subarachnoid space (L3.4 interspace) and advanced caudally until lumbar region.Group R received hyperbaric 0.5％ ropivacaine 1.5 ml.Group RF received 2.0 ml mixture of hyperbaric 0.3％ ropivacaine 6.0 mg and fentanyl 10μg.The onset time of sensory and motor block,upper level of sensory block,and duration of sensory and motor block were recorded.Motor block was assessed by modified Bromage scale.Results Compared with group R,the duration of sensory and motor block was significantly shortened,and modified Bromage scores were significantly decreased in group RF (P ＜ 0.05 or 0.01),and no significant change was found in the onset time of sensory and motor block and upper level of sensory block between the two groups (P ＞ 0.05).Conclusion 0.3 ％ ropivacaine 6.0 mg combined with fentanyl 10 μg provides satisfactory spinal anesthesia for anorectal surgery,with lower degree and faster recovery of motor block.

Objective To evaluate the effects of different head-down tilt (HDT) angles on respiratory mechanics and cerebral circulation during laparoscopic radical resection of rectal carcinoma in the patients.Methods Thirty patients of both sexes,aged 40-64 yr,of ASA physical status Ⅰ or Ⅱ,with body mass index ＜ 30 kg/m2,scheduled for elective laparoscopic radical resection of rectal carcinoma,were included in the study.Anesthesia was induced with midazolam,fentanyl,propofol and cis-atracurium and maintained with targetcontrolled infusion of propofol and remifentanil and cis-atracurium when needed.At 5 min after supine position,5 min after 30° HDT,5 min after 35° HDT,5 min after 40° HDT,and 30 min after pneumoperitoneum (T1-5),airway pressure (Paw),peak airway pressure (PIP),lung compliance (Cpat) and jugular bulb blood pressure (JBP) were recorded.Blood samples were taken from the radial artery and jugular bulb for blood gas analysis and arterial partial pressure of oxygen (PaO2),partial pressure of carbon dioxide in artery (PaCO2),arterial oxygen saturation (SaO2),jugular bulb oxygen partial pressure (PjvO2),and jugular bulb venous saturation (SjvO2) were recorded at each time point mentioned above.Results Paw,PIP,MAP,PaCO2,JBP,PjvO2 and SjvO2 were significantly increased as compared with those obtained when the patients were in supine position,increased gradually with the increasing HDT angles,and decreased to the level obtained when the patients were in supine position at 30 min after pneumoperitoneum.Cpat and PaO2 were significantly decreased as compared with those obtained when the patients were in supine position decreased gradually with the decreasing HDT angles,and increased to the level obtained when the patients were in supine position at 30 min after pneumoperitoneum.Conclusion HDT-induced effects on respiratory mechanics and cerebral circulation increase with increasing angles during laparoscopic radical resection of rectal carcinoma; thus the optimum HDT angle is smaller than 40° for the patients undergoing this kind of surgery.

Objective To evaluate the effect of 6% hydroxyethyl starch 130∕0. 4 on acute kidney injury in elderly patients in a prospective, multicenter, randomized, double?blind, controlled clinical tri?al. Methods A total of 120 patients of both sexes, aged 65-82 yr, weighing 56-83 kg, of American So?ciety of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective orthopaedics and hernia surgery, were divided into either hydroxyethyl starch group ( group HES) or lactated Ringer′s solution group ( group LR) , with 60 patients in each group. Hydroxyethyl starch and lactated Ringer′s solution were infused intra?venously at a rate of 7. 5 ml∕kg during 1st hour of surgery in HES and LR groups, respectively. Lactated Ringer′s solution was then infused at a rate of 5 ml∕kg starting from 2nd hour of surgery until the end of sur?gery in both groups. Before surgery, at the end of surgery and at 1, 3 and 5 days after surgery, blood sam?ples and urine specimens were collected for determination of the concentrations of neutrophil gelatinase?asso?ciated lipocalin, interleukin?18 (IL?18), plasma creatinine, urine β2 microglobulin and urine albumin.
The estimated glomerular filtration rate was calculated. Results The level of urine IL?18 was significantly higher at each time point after surgery than before surgery and immediately after the end of surgery ( P<0.05) . There were no significant differences between the two groups in the levels of urine IL?18, plasma creatinine, plasma and urine neutrophil gelatinase?associated lipocalin, plasma IL?18, urineβ2 microglob?ulin and urine albumin and estimated glomerular filtration rate at each time point ( P>0.05) . Conclusion Compared with lactated Ringer′s solution, 6% hydroxyethyl starch 130∕0.4 does not aggravate acute kidney injury in elderly patients.

Objective To evaluate the efficacy of preoperative transversus abdominis plane (TAP) block for improving analgesia after radical resection of colorectal cancer in elderly patients.Methods Fiftysix American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients of both sexes,aged 75-86 yr,weighing 52-78 kg,scheduled for elective radical resection of colorectal cancer under general anesthesia,were divided into 2 groups (n=28 each) using a random number table:TAP block group (group T) and control group (group C).After anesthesia induction,ultrasound-guided bilateral TAP block was performed,and 0.40％ ropivacaine 25 ml was injected into each side in group T.Both groups received patientcontrolled intravenous analgesia (PCIA) with fentanyl after surgery.PCIA solution contained fentanyl 600 μg and azasetron 10 mg in 100 ml of normal saline.The PCIA pump was set up with a 2 ml bolus dose,a 15 min lockout interval and background infusion at a rate of 2 ml/h,and visual analogue scale score was maintained≤ 3.When the visual analogue scale score＞3,tramadol 50-100 mg was intravenously injected as rescue analgesic.The number of patients requiring rescue analgesic,consumption of fentanyl during PCIA and the number of successfully delivered doses were recorded within 24 h after surgery.The adverse reactions such as hematoma at the puncture site,nausea and vomiting,respiratory depression,chest tightness and pruritus were recorded.Results Compared with group C,the number of patients requiring rescue analgesic was significantly decreased,and the consumption of fentanyl and the number of successfully delivered doses during PCIA were decreased in group T (P＜0.05).No hematoma was found at the puncture site in group T.No respiratory depression,chest tightness or pruritus was found in the two groups,and there were no significant differences in the incidence of nausea and vomiting between the two groups (P＞0.05).Conclusion Preoperative TAP block can reduce the consumption of fentanyl and enhance the efficacy of analgesia after radical resection of colorectal cancer in elderly patients.

Objective To evaluate the relationship between the change rate of regional cerebral ox-ygen saturation ( rSO2 ) and early postoperative cognitive function during laparoscopic surgery in elderly pa-tients. Methods Fifty American Society of Anesthesiologists physical status Ⅰ-Ⅱ patients, aged 65-80 yr, scheduled for elective laparoscopic radical resection for colorectal cancer under general anesthesia, were enrolled in this study. rSO2 was recorded at 5 min before anesthesia induction ( T0 ) , 5 min after tra-cheal intubation ( T1 ) , 5 min after changing position ( T2 ) , 1 h after changing position ( T3 ) , 5 min after stopping pneumoperitoneum ( T4 ) , and 5 min after changing to supine position at the end of pneumoperito-neum ( T5 ) . The change rate of rSO2 was calculated at T3 . Mini-Mental State Examination scores were per-formed at 1 day before surgery and 3 days after surgery. The patients were divided into cognitive disorder group and non-cognitive disorder group. Results Compared with non-cognitive disorder group, rSO2 was significantly increased at T2-5 , and the change rate of rSO2 was enlarged in cognitive disorder group ( P<0. 05) . The change rate of intraoperative rSO2 was negatively correlated with Mini-Mental State Examination scores at 3 days after surgery (r=-0. 516, P<0. 01). Conclusion The increased change rate of rSO2 during laparoscopic surgery may be related to the development of early postoperative cognitive dysfunction in elderly patients.