Possible Risk Factors for Severe Complications Occurring after Primary Total Knee Arthroplasty.

Objective Total knee arthroplasty is one of the most common orthopedic surgeries. Readmission due to severe complications after total knee arthroplasty is a grave concern to surgeons. In this study, we evaluated the risk factors for severe complications after primary total knee arthroplasty. Methods We retrospectively collected clinical data of 2,974 patients who underwent primary total knee arthroplasty from July 2013 to June 2019 in our hospital. Postoperative complication ≥ grade Ⅲ was defined as severe complication according to Clavien-Dindo classification system. Binary logistic regression was used to identify the predictive risk factors for severe complications. Results The complication rate after primary total knee arthroplasty was 6.8% and severe complication rate was 2.5%. Male (OR = 2.178, 95%CI: 1.324-3.585, P= 0.002), individuals above 75 years old (OR = 1.936, 95%CI: 1.155-3.244, P= 0.012), arrhythmia (OR = 2.913, 95%CI: 1.350-6.285, P= 0.006) and cerebrovascular disease (OR = 2.804, 95%CI: 1.432-5.489, P= 0.003) were predictive risk factors for severe complications after primary total knee arthroplasty. Conclusion Advanced age, male, arrhythmia, and cerebrovascular disease might be patients-related risk factors for postoperative severe complications after primary total knee arthroplasty. Special attention should be paid to patients with risk factors.

[Association of Perioperative Allogeneic Red Blood Cell Transfusion with Postoperative Infections].

Allogeneic red blood cell transfusion can induce transfusion-related immunomodulation while correcting anemia and improving oxygenation,and thus may be associated with the increased risk of postoperative infections.However,the available studies have conflicting conclusions.Preclinical studies demonstrate transfusion-related immunomodulation is associated with transfusion amounts.Stored red blood cells can cause more significant immunosuppression than fresh blood products,while leukoreduction alleviates the negative effect on immune system.However,clinical studies do not reach agreements on these issues.Recently,accumulating multi-center,large-sample-size,real-world studies have reported significant associations of all ogeneic red blood cell transfusion in cardiac,orthopedic,hepatic,pancreatic,gastrointestinal,and vesical surgeries with postoperative infections.Considering the limitations of previous studies,future research should focus on multiple operations,prolong the time interval between transfusion and surgery,include different infections into outcomes,and define the postoperative infections accurately in the premise of adequate samples.High-quality clinical evidence could help to optimize the utilization of blood products and improve the postoperative outcomes.

Recurrent Myocardial Infarction and Catecholamine-Induced Cardiomyopathy: A Case Report.

Pheochromocytomas or paragangliomas are rare and the diagnosis remains a challenge for clinicians. We present a woman suffering from recurrent myocardial infarction and cardiomyopathy, who was finally diagnosed with paraganglioma. Pheochromocytomas or paraganglioma should be considered in the differential diagnosis of a patient with symptoms possibly referring to acute coronary syndrome and cardiomyopathy.

Assessing Empathy in Anesthesia Residents with the Chinese Version of the Consultation and Relational Empathy: A Pilot Standardized Patient Program.

Objectives To validate the reliability of the Chinese version of the Consultation and Relational Empathy (CARE) in physician-standardized patient (SP) encounter. We also tried to examine the agreement between video-based ratings and in-room ratings, as well as the agreement between the faculty ratings and SP ratings. Methods The CARE was translated into Chinese. Forty-eight anesthesia residents were recruited to make preoperative interview in SP-counter. Performance of each resident was graded by in-room raters, video raters and SP raters. Consistency between different raters was examined. Results The Chinese-CARE measure demonstrated high scale reliability with a Cronbach's alpha value of 0.95 and high consistency in the in-room ratings in intraclass correlation (coefficient=0.888,P<0.001). Despite a good consistency in intraclass correlation, video ratings were significantly higher than in-room ratings (39.6±7.1vs. 24.0±10.0,P<0.001), and Wilcoxon signed-rank test indicated that the pass/fail rate was significantly higher based on video ratings than based on in-room ratings (45/48vs. 22/48, P<0.001). SP ratings had a moderate consistency with in-room faculty ratings (coefficient=0.568,P<0.001), and there was no significant difference between the pass/fail rates based on the in-room ratings and SP ratings (22/48vs. 28/48, P=0.12). Conclusions The Chinese-CARE measure is reliable in the assessment of empathy during preoperative anesthesia interview. In-room and video ratings are not equivalent, while SP may provide a feasible alternative for the faculty rater in the assessment of communication skills with an appropriate measure.

A Survey of Surgical Patient's Perception about Anesthesiologist in a Large Scale Comprehensive Hospital in China.

Objectives This study aim to evaluate patient's perception about anesthesiologists' job roles and investigate their expectations for anesthesia care.Methods We designed a self-administered questionnaire for this cross-sectional survey study and delivered questionnaire forms to adult in-patients who were scheduled for elective surgery before pre-operative anesthetic visit the day before surgery. We collected information of respondents' demographic data, education background, health literacy and previous experience of anesthesia, perception of anesthesiologist's job, the expectation on anesthesia care. Descriptive analyses, χ [2] test and multiple linear regression analysis were used for data analysis. Results Of 550 participants, 521（94.7%）completed the questionnaire. In these respondents, 335 (64.3%) considered anesthesiology as an independent medical discipline, 225 (43.2%) believed that anesthesiology department was an independent clinical department, and 243 (46.6%) recognized anesthesiologists as qualified doctors. Only 21.5% of them knew that anesthesiologists also work in the intensive care unit and 26.9% of them knew that anesthesiologists also work in pain clinic as well. Younger patients (ß=-0.044, P<0.001), those with higher education (ß=1.200, P<0.001), or with better health literacy (ß=0.781, P=0.005) had significant more knowledge about the job roles of anesthesiologists. Most patients demanded pre-anesthetic visit (80.5%), expected availability of preoperative anesthetic clinic (74.1%), wished to receive more information about anesthesia (91.3%) and anesthesiologist (77.4%).Conclusions Patients' perception about anesthesiologists might be limited. Efforts should be made on education about anesthesia, especially for elderly patients and those under-educated patients. Preoperative anesthetic clinic is expected by most in-patients.

Prediction of Hidden Blood Loss During Posterior Spinal Surgery.

Objective Identification of the risk factors for extraordinary hidden blood loss (HBL) could clarify the underlying causes and provide more appropriate management. This study aims to identify the predictors of HBL in spinal surgery.Methods Medical records were retrospectively retrieved to collect the data of patients who undergoing posterior thoracic and lumbar fusion surgery or scoliosis surgery. Demographic information, perioperative visible blood loss volume, as well as laboratory results were recorded. The patients receiving fusion surgery or scoliosis surgery were further divided into the HBL positive subgroup and the HBL negative subgroup. Differences in the variables between the groups were then analyzed. Binary logistic regression analysis was performed to determine independent risk factors associated with HBL.Results For patients undergoing posterior spinal surgery, the independent risk factors associated with HBL were autologous transfusion (for fusion surgery P=0.011, OR: 2.627, 95%CI: 1.574-2.782; for scoliosis surgery P<0.001, OR: 2.268, 95%CI: 2.143-2.504) and allogeneic transfusion (for fusion surgeryP<0.001, OR: 6.487, 95%CI: 2.349-17.915; for scoliosis surgery P<0.001, OR: 3.636, 95%CI: 2.389-5.231).Conclusions Intraoperative blood transfusion might be an early-warning indicator for perioperative HBL.

[Perioperative Restrictive Red Blood Cell Transfusion:Recent Advances in Research and Clinical Guidelines].

Perioperative restrictive red blood cell(RBC)transfusion strategy,in which a trigger of hemoglobin(Hb)<7 g/dl is used,is of great benefits to save blood storage and reduce transfusion-related adverse events including infections,immunologic risks,and circulatory overload.Human body can display a series of compensatory mechanisms to acute anemia,including increased cardiac output,favored oxyhemoglobin dissociation,and lung vascular dilation.Therefore,moderate Hb decrease does not necessarily lead to hypoxemia.Patients undergoing hip surgery or suffering from septic shock and/or upper gastrointestinal bleeding can benefit from restrictive RBC transfusion;however,restrictive transfusion may be associated with adverse outcomes in patients with coronary heart disease or undergoing cardiac surgery.Restrictive RBC transfusion strategies have been included in described in many different guidelines.Most of them recommended Hb<7 g/dl to be a trigger for allogeneic RBC transfusion.For patients with an Hb of 7-10 g/dl,the application of restrictive RBC transfusion should be based on the expected blood loss,compensatory ability,and metabolic rate.

Irrationality of Allogeneic Red Blood Cell Transfusion in Intraoperative Cell Salvage Patients: a Retrospective Analysis.

Objective Although intraoperative cell salvage (ICS) has been widely used to reduce the demand for allogeneic blood transfusion, patients who use ICS approach still have not completely avoided chances of blood transfusion. This study aims to investigate the rate of allogeneic red blood cell(RBC) transfusion in patients receiving ICS, and to evaluate irrationality of allogeneic RBC transfusion and its risk factors.Methods Medical records of all patients associated with ICS approach from January 2013 to July 2014 were retrospectively reviewed. Theoretical hemoglobin level after reinfusion of salvaged RBC at the end of operations was estimated. Irrational transfusion was defined as initiating allogeneic transfusion with theoretical hemoglobin above 100 g/L. The clinical variables, including the surgical department, gender, age, body weight, ratio of blood loss to estimated blood volume(EBV), salvaged blood volume and preoperative hemoglobin level were subsequently compared between patients who received rational transfusion and those did not. Logistic regression was performed to identify the risk factors for irrationality of allogeneic RBC transfusion in these patients.Results Of 1487 patients with ICS approach in this study, the rate of allogeneic RBC transfusion was 31.4%(467/1487), and the rate of irrational allogeneic RBC transfusion was 26.0% (341/1313). Patients with irrational transfusion were younger (t=4.656, P<0.001), with lower body weight (t=3.910, P<0.001) and slightly lower preoperative HGB level (t=2.822, P=0.005) than those with rational transfusion, but had significantly larger salvaged blood volume (U=-10.926, P<0.001) and higher ratio of blood loss to EBV (U=-17.067, P<0.001), disregarding whether they preoperatively met anemia criteria or not (U=-1.396, P=0.163). Preoperative hemoglobin level (OR=1.975, P=0.005) and the ratio of blood loss/EBV (OR=5.392, P<0.001) were independent risk factors leading to the irrational allogeneic RBC transfusion.Conclusions The irrationality of allogeneic RBC transfusion existed in ICS patients, which may be associated with the preoperative hemoglobin level and the ratio of blood loss to EBV. Determining the HGB levels before transfusion is required to avoid unnecessary blood administration. Doctors should keep their knowledge in blood management updated and improve their awareness of rational transfusion for a better patients care.

Perioperative Safety of Patients Undergoing Unilateral or Simultaneous Bilateral Total Knee Arthroplasty.

Objective To analyze the perioperative safety of patients undergoing unilateral or simultaneous bilateral total knee arthroplasty(TKA). Methods Totally 500 patients who had undergone unilateral or simultaneous bilateral TKA between December 2014 to December 2015 were retrospectively reviewed. They were divided into two groups:unilateral group(n=310)and bilateral group(n=190).The general data,perioperative transfusion,and complications were compared between these two groups. Results Patients in unilateral group had significantly higher ASA scores(χ2=8.344,P=0.015) and NYHA grade(χ2=7.537,P=0.023)than in bilateral group.Patients in bilateral group had significantly higher posterior drainage volume(t=44.984,P=0.000). Transfusion rate(χ2=42.896,P=0.000) was significantly higher and the lowest postoperative hemoglobin was significantly lower(t=0.006,P=0.000)in the bilateral group. The episodes of transfusion(χ2=1.025,P=0.599) and the amount of transfused packed red blood cells(χ2=3.836,P=0.429) were similar between two groups. There was no significant difference in the length of postoperative hospital stay(t=0.310,P=0.756),admission to intensive care unit(χ2=0.317,P=0.895),and incidences of complications(χ2=0.047,P=0.475). Conclusions For patients with low ASA scores and NYHA grade,simultaneous bilateral TKA is recommended. For older patients with high ASA score,poor cardiac function,and high incidences of complications,unilateral TKA is recommended.

Effect of Point-of-care Hemoglobin/Hematocrit Devices and Autologous Blood Salvage on Reduction of Perioperative Allogeneic Blood Transfusion.

Objective To evaluate the effect of point-of-care hemoglobin/hematocrit (POC HGB/HCT) devices and intraoperative blood salvage on the amount of perioperative allogeneic blood transfusion and blood conservation in clinical practice.Methods A total of 46 378 medical records of 22 selected hospitals were reviewed. The volume of allogeneic red blood cell and plasma, number of patients transfused, number of intraoperative autologous blood salvage, total volume of autologous blood transfusion, and amount of surgery in the year of 2011 and 2013 were tracked. Paired t-test was used in intra-group comparison, while t-test of two isolated samples carried out in inter-group comparison. P<0.05 was defined as statistically significant difference.Results In the hospitals where POC HGB/HCT device was used (n=9), the average allogeneic blood transfusion volume per 100 surgical cases in 2013 was significantly lower than that in 2011 (39.86±20.20 vs. 30.49±17.50 Units, t=3.522, P=0.008). In the hospitals without POC HGB/HCT meter, the index was not significantly different between 2013 and 2011. The average allogeneic blood transfusion volume was significantly reduced in 2013 than in 2011 in the hospitals where intraoperative autologous blood salvage ratio [autologous transfusion volume/(autologous transfusion volume+allogeneic transfusion volume)] was increased (n=12, t=2.290, P=0.042). No significant difference of the above index was found in the hospitals whose autologous transfusion ratio did not grow.Conclusion Intraoperative usage of POC HGB/HCT devices and increasing autologous transfusion ratio could reduce perioperative allogeneic blood transfusion.

Influence of Anesthetic Brochure on Patient's Information Gain, Preoperative Anxiety, Trust, and Satisfaction.

Objective To assess the impacts of anesthetic brochure on anesthetic information gain, preoperative anxiety, trust to anesthesiologists, and satisfaction to the preanesthesia visit for patients undergoing general anesthesia. Methods Totally 134 patients scheduled for elective thyroid surgery under general anesthesia in Peking Union Medical College Hospital were assigned to two groups using the random number table method, among whom 68 patients received brochure before preoperative visit (brochure group) and 66 patients did not (control group). Questionnaires with items for evaluating patient's information gain, preoperative anxiety and trust were completed after preanesthetic visit. Patient's satisfaction with preanesthetic visit was evaluated on the second postoperative day. Results Compared with the control group, patients in the brochure group had significantly higher information gain scores (7.2±1.8 vs. 5.2±2.1, P<0.001) and satisfaction scores (25.0±3.4 vs. 22.7±3.1, P<0.001). There was no significant difference in anxiety scores and trust scores between these two groups. Conclusion Preoperative anesthetic brochure-assisted education can improve information gain and satisfaction among patients undergoing general anesthesia; however, it can not remarkably alter patient's preoperative anxiety and trust.

Predictors for Massive Blood Loss During Posterior Correction of Congenital Scoliosis in Pre-school Children:A Retrospective Observation.

Objective To investigate the predictors for massive blood loss during posterior correction of congenital scoliosis in pre-school children. Methods Totally 124 children under six years of age,who received posterior correction of congenital scoliosis,were divided into two groups according to the ratio of intraoperative blood loss (BL) and estimated blood volume (EBV). Massive blood loss was defined as BL/EBV>0.15,and minor or moderate blood loss as BL/EBV≤0.15. All the records,including demographics,intraoperative fluids,pre- or postoperative laboratory parameters,and the length of hospital stay,were compared between these two groups. Results There were 57 children in the moderate or minor blood loss group and 67 children in the massive blood loss group. When compared with moderate or minor blood loss group,children in massive blood loss group had significantly lower body weight,shorter body height,longer anesthesia period,and more autologous or allogeneic transfusion (P<0.05). Binary Logistic regression analysis showed that body weight lower than 15 kg was the independent predictor for massive blood loss (OR=0.435,95% CI=0.197-0.962). Conclusions The incidence of massive blood loss is about 54% in children under six years of age who have received posterior correction of congenital scoliosis. The body weight of lower than 15 kg is an independent predictor for massive blood loss during the surgery.

Anesthesia Strategies and Perioperative Optimization for Patients with Ankylosing Spondylitis Undergoing Total Hip Replacement Surgery.

Objective To identify the characteristics of anesthesia and perioperative management for ankylosing spondylitis (AS) patients undergoing total hip arthroplasty (THA). Methods Totally 63 patients scheduled for single THA in PUMC Hospital from January 1st 2013 to June 1st 2015 were included in this retrospective analysis,among whom 21 patients were diagnosed of AS. The perioperative clinical data included:demographic data,American Society of Anesthesiologists (ASA) classification,medical history,airway assessment,preoperative laboratory examinations,electrocardiogram,pulmonary function tests,intubation information,operation time,intraoperative intake and output volume,postoperative hospital stay,and postoperative complications. Results Significantly fewer AS patients undergoing THA were evaluated as ASA classification I than non-AS patients (9.5% vs. 33.3%,P=0.041). AS patients had significantly higher level of preoperative high-sensitivity C-reactive protein [(17.0±14.8)mg/L vs.(4.3±7.1)mg/L,P<0.001],platelets [(275.0±71.3)×10(9)/L vs. (237.7±68.0)×10(9)/L,P=0.048] and neutrophils [(4.7±1.7)×10(9)/L vs. (3.9±1.4)×10(9)/L,P=0.044] and higher incidence of pulmonary function abnormality (42.9% vs.16.7%,P=0.024).More AS patients were induced with scoline (14.3% vs.0,P=0.012). More AS patients underwent THA with Mallampati classification 3 (28.6% vs.7.1%,P=0.022),reduced neck extension(47.6% vs.2.4%,P<0.001),Cormack-Lehane classification2(56.3% vs.15.4%,P=0.002)and 3 (18.8% vs.0,P=0.005),while much fewer AS patients had Cormack-Lehane classification1 (25.0% vs.84.6%,P<0.001).A variety of difficult airway tools were used in intubation (AS group:Macintosh laryngoscope:14%,Macintosh laryngoscope with stylet:38%,visualization laryngoscope:24%,visualization stylet:10% and fiber bronchoscope:14%;non-AS group:57%,24%,12%,5% and 2%,respectively). The use of intraoperative autologous blood transfusion (33.3% vs.11.9%,P=0.041) and postoperative 24 h drainage (61.9% vs.31.0%,P=0.019) were more common in AS group. However,no statistical difference existed in the success rate of first intubation,postoperative hemoglobin,postoperative hematocrit,and postoperative hospitalization(all P>0.05). Conclusions AS patients undergoing THA have elevated preoperative inflammatory markers,with high incidence of pulmonary function abnormality and difficult airway. In consideration of high risk of surgery and anesthesia,adequate airway evaluation and optimization of perioperative management are needed to ensure the patients' safety.

Influence of Sex on Remifentanil's Cough-prevention Effect during Anesthetic Emergence.

OBJECTIVE: To investigate the influence of sex on the cough-preventing effect of target-controlled infusion(TCI)of remifentanil during anesthetic emergence. METHODS: A total of 25 female(group F)and 25 male(group M)patients undergoing thyroidectomy were recruited in the current study. Anesthesia was maintained with sevoflurane and remifentanil TCI.At the end of the surgery,inhalational anesthetics were discontinued,and remifentanil TCI at an effect-site concentration(Ce)of 2.0 ng/ml was maintained during emergence until extubation. The cough score,blood pressure,and heart rate(HR)during peri-extubation period as well as the respiratory rate,calm score,and sore throat score after extubation were evaluated. RESULTS: During extubation,the proportion of patients with no cough or just a single cough was significantly higher in group F than in group M(88% vs. 64%,P=0.047). Mean arterial pressure(P=0.025,P=0.037)and HR(P=0.035)were significantly increased during extubation compared with preoperative levels in group M. CONCLUSIONS: Sex may influence the cough-preventing effect of remifentanil TCI during anesthetic emergence. At a Ce of 2.0 ng/ml,remifentanil has better cough-preventing effect and more stable hemodynamic status in females than in males.

Evaluation of risk factors for arytenoid dislocation after endotracheal intubation: a retrospective case-control study.

OBJECTIVE: To investigate the risk factors for postoperative arytenoid dislocation. METHODS: From September 2003 to August 2013, the records of 16 patients with a history of postoperative arytenoid dislocation were reviewed. Patients matched in terms of date and type of procedures were chosen as the controls (n=16). Recorded data for all patients were demographics, smoking status, alcoholic status, preoperative physical status, airway evaluation, intubation procedures, preoperative laboratory test results, anesthetic consumption and intensive care unit stay. For arytenoid dislocation cases, we further analyzed the incidences of the left and right arytenoid dislocation, and the outcomes of surgical repair and conservative treatment. Categorical variables were presented as frequencies and percentages, and were compared using the chi-squared test. Continuous variables were expressed as means±SD and compared using the Student's unpaired t-test. To determine the predictors of arytenoid dislocation, a logistic regression model was used for multivariate analysis. RESULTS: Sixteen patients with postoperative arytenoid dislocation were enrolled, with a median age of 52 years. Most postoperative arytenoid dislocation patients (15/16, 93.75%) received surgical repair, except one patient who recovered after conservative treatment. None of the postoperative arytenoid dislocation patients were smokers. Red blood cell (P=0.044) and hemoglobin (P=0.031) levels were significantly lower among arytenoid dislocation cases compared with the controls. CONCLUSIONS: Non-smoking and anemic patients may be susceptible to postoperative arytenoid dislocation. However, neither of them was independent risk factor for postoperative arytenoid dislocation.

[Triggers, mechanisms, and potential clinical applications of cerebral ischemic tolerance].

Ischemic tolerance exists in many organs, among which the cerebral ischemic tolerance and its potential clinical applications are most notable. The discovery of new triggers of cerebral ischemic tolerance has brought more interesting insights into the molecular mechanisms. The remote ischemic preconditioning and pharmacological induction of cerebral ischemic tolerance have shown promising clinical safety and feasibility, and therefore may be important breakthroughs in the clinical application of cerebral ischemic tolerance.

[Expressions of neuropathic pain-related proteins in the spinal cord dorsal horn in rats with bilateral chronic constriction injury].

OBJECTIVE: To evaluate the pain-related behavioral changes in rats with bilateral chronic constriction injury(bCCI)and identify the expressions of neuropathic pain-related proteins. METHODS: The bCCI models were established by ligating the sciatic nerves in female Sprague Dawley rats. Both mechanical hyperalgesia and cold hyperalgesia were evaluated through electronic von Frey and acetone method. Liquid chromatography-mass spectrometry/mass spectrometry was applied to characterize the differentially expressed proteins. RESULTS: Both mechanical withdrawal threshold and cold hyperalgesia threshold decreased significantly on the postoperative day 7 and 14, when compared with na ve or sham rats(P <0.05). Twenty five differentially expressed proteins associated with bilateral CCI were discovered, with eighteen of them were upregulated and seven of them downregulated. CONCLUSIONS: The bCCT rats have remarkably decreased mechanical and cold hyperalgesia thresholds. Twenty five neuropathic pain-related proteins are found in the spinal cord dorsal horn.

Intraoperative thromboelastography-guided transfusion in a patient with factor XI deficiency: A case report.

BACKGROUND: Factor XI (FXI) deficiency, also known as hemophilia C, is a rare bleeding disorder of unpredictable severity that correlates poorly with FXI coagulation activity. This often poses great challenges in perioperative hemostatic management. Thromboelastography (TEG) is a method for testing blood coagulation using a viscoelastic hemostatic assay of whole blood to assess the overall coagulation status. Here, we present the successful application of intraoperative TEG monitoring in an FXI-deficient patient as an individualized blood transfusion strategy. CASE SUMMARY: A 21-year-old male patient with FXI deficiency was scheduled to undergo reconstructive surgery for macrodactyly of the left foot under general anesthesia. To minimize his bleeding risk, he was scheduled to receive fresh frozen plasma (FFP) as an empirical prophylactic FXI replacement at a dose of 15-20 mL/kg body weight (900-1200 mL) before surgery. Subsequent FFP transfusion was to be adjusted according to surgical need. Instead, TEG assessment was used at the beginning and toward the end of his surgery. According to intraoperative TEG results, the normalization of coagulation function was achieved with an infusion of only 800 mL FFP, and blood loss was minimal. The patient showed an uneventful postoperative course and was discharged on postoperative day 8. CONCLUSION: TEG can be readily applied in the intraoperative period to individualize transfusion needs in patients with rare inherited coagulopathy.

[Perioperative airway management for patients with morbid obesity].

The excess fatty tissues on the head, neck, thorax, and abdomen of morbid obese patients can impede the patency of the upper airway and impair lung functions. Meanwhile, these patients often have comorbidities such as obstructive sleep apnea, hypoventilation syndrome, chronic obstructive pulmonary disease, and asthma, which may result in difficult airway, intraoperative hypoventilation, and postoperative respiratory depression. Therefore, perioperative airway management for morbid obese patients may pose a big challenge to anesthesiologists. Anesthesiologists should know well about the pathophysiological features of respiratory system and grasp rational management principles, so as to improve the safety and effectiveness of perioperative airway management and optimize the clinical prognosis.

[Expression changes of metabotropic glutamate receptor 5 in neuropathic pain].

OBJECTIVE: To investigate the expression changes of metabotropic glutamate receptor 5 (mGluR5) in neuropathic pain. METHODS: Eighty-four adult male Sprague Dawley rats weighing 180-220 g were randomly divided into 7 groups (n = 12) : control group; S3, S7, and S14 groups: rats received the sham operation, the mechanical pain threshold was measured, and then the rats were decapitated and the ipsilateral lumbar spinal cord dorsal horn and dorsal root ganglion (DRG) samples were obtained on the 3rd, 7th, 14th postoperative day, respectively; C3, C7, and C14 groups: the chronic sciatic nerve constriction (CCI) model was established, the mechanical pain threshold was measured and the samples were obtained on the 3rd, 7th, 14th postoperative day, respectively. The expression level of mGluR5 mRNA and protein in the spinal cord and DRG were measured using the reverse transcriptase polymerase chain reaction and Western blot. RESULTS: In the CCI group, the mechanical pain threshold in each observation day was significantly lower than in the sham operation group (P < 0.05). In the spinal cord, the expressions of mGluR5 mRNA and protein were significantly elevated in the C3 group than in the S3 and the control group (P < 0.05). On the 7th and the 14th postoperative day, no significant difference was found in the expression of mGluR5 mRNA and protein between CCI groups and the sham operation groups or the control group. No change was detected in DRG mRNA or protein. CONCLUSION: mGluR5 is differentially expressed in spinal cord in response to neuropathic pain, which suggests that mGluR5 may be involved in the mechanism of neuropathic pain.