Genetic Evidence for Causal Association Between Hypertension and Chronic Pain:A Bidirectional Two-Sample Mendelian Randomization Study

Objective The extent to which the association between hypertension and chronic pain in observational studies is either causally linked or influenced by other shared risk factors has not been substantially addressed.In the present study,Mendelian randomization(MR)was employed to examine the potential causal relationship between hypertension and risk of chronic pain.Methods The study data were derived from the pooled dataset of the genome-wide association study(GWAS),enabling the evaluation of the causal effects of hypertension on various types of chronic pain including chronic headache as well as chest,abdominal,joint,back,limb,and multisite chronic pain.We performed a bidirectional two-sample MR analysis using random effect inverse variance weighting(IVW),MR-Egger,weighted median,and weighted mode,quantified by odds ratio(OR).Results Genetically predicted essential hypertension was associated with an increased risk of chronic headache(OR=1.007,95%CI:1.003-1.011,P=0.002)and limb pain(OR=1.219,95%CI:1.033-1.439,P=0.019).No potential causal associations were identified between chronic pain and essential hypertension in the reverse direction MR(P>0.05).In addition,there was no potential causal association between secondary hypertension and chronic pain(P>0.05).Conclusion This study provided genetic evidence that a unidirectional causal relationship exists between essential hypertension and the increased risks of chronic headache and limb pain,and no causal relationship was found between secondary hypertension and chronic pain.These findings offer theoretical underpinnings for future research on managing hypertension and chronic pain.

Intraoperative Blood Pressure Lability Acts as a Key Mediator in the Impacts of Goal-Directed Fluid Therapy on Postoperative Complications in Patients Undergoing Major Spine Surgery

Objective Although goal-directed fluid therapy(GDFT)has been proven to be effective in reducing the incidence of postoperative complications,the underlying mechanisms remain unknown.The aim of this study was to examine the mediating role of intraoperative hemodynamic lability in the association between GDFT and the incidence of postoperative complications.We further tested the role of this mediation effect using mean arterial pressure,a hemodynamic indicator.Methods This secondary analysis used the dataset of a completed nonrandomized controlled study to investigate the effect of GDFT on the incidence of postoperative complications in patients undergoing posterior spine arthrodesis.We used a simple mediation model to test whether there was a mediation effect of average real variability between the association of GDFT and postoperative complications.We conducted mediation analysis using the mediation package in R(version 3.1.2),based on 5,000 bootstrapped samples,adjusting for covariates.Results Among the 300 patients in the study,40%(120/300)developed postoperative complications within 30 days.GDFT was associated with fewer 30-day postoperative complications after adjustment for confounders(odds ratio:0.460,95%CI:0.278,0.761;P=0.003).The total effect of GDFT on postoperative complications was-0.18(95%CI:-0.28,-0.07;P<0.01).The average causal mediation effect was-0.08(95%CI:-0.15,-0.04;P<0.01).The average direct effect was-0.09(95%CI:-0.20,0.03;P=0.17).The proportion mediated was 49.9%(95%CI:18.3%,140.0%).Conclusions The intraoperative blood pressure lability mediates the relationship between GDFT and the incidence of postoperative complications.Future research is needed to clarify whether actively reducing intraoperative blood pressure lability can prevent postoperative complications.

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.

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.

Urgent Tracheal Resection and Reconstruction Assisted by Temporary Cardiopulmonary Bypass:a Case Report

SEVERE tracheal stenosis can not only cause criti- cal medical problems such as severe shortness of breath, hypoxia, and even orthopnea, but also impose overwhelming challenges on thephysicians, particularly the anesthesiologist. Life-threa- tening airway obstruction can make the patient＇s gas ex- change extremely difficult. Though several options could be offered regarding the treatment of tracheal stenosis, normally, tracheal resection and following reconstruction is the first choice for severe airway stenosis.1 Successful surgical intervention relies on the close communication and cooperation between surgeons and anesthesiologists.

Ultrasound-guided Transversus Abdominis Plane Block Improves Postoperative Analgesia and Early Recovery in Patients Undergoing Retroperitoneoscopic Urologic Surgeries:A Randomized Controlled Double-blinded Trial

Objective To evaluate the effects of ultrasound-guided transversus abdominis plane(TAP) block on postoperative analgesia and early recovery in patients undergoing retroperitoneoscopic urologic surgeries.Methods This was a randomized,controlled,double-blinded trial.Eligible patients scheduled for retroperitoneoscopic urologic surgeries were randomly assigned to two groups.Group TAP received ultrasound-guided TAP block with 0.5% ropivacaine 20 ml at 30 minutes before surgery,and Group C received TAP sham block with normal saline.All patients received retroperitoneoscopic urologic surgeries under general anesthesia.The primary outcome was the severity of pain after surgery.Secondary outcomes included opioids consumption,analgesics,postoperative nausea and vomiting,time to Foley catheter removal and to passage of flatus,length of post-anesthesia care unit stay and hospital stay.Results Eighty patients completed the study,forty cases in each group.Compared to the Group C,the Group TAP had lower visual analogue scale pain scores within two postoperative days(all P<0.05).They also had less consumption of intraoperative fentanyl(2.0±0.5 vs. 3.8±0.7 μg/kg,P<0.05),reduced incidence of postoperative rescue analgesic usage(12.5% vs. 45.0%,P<0.05),and lower incidence of postoperative nausea and vomiting within postoperative 48 hours(12.5% vs. 25.0%,P<0.05) when compared to the Group C.In addition,Group TAP had a shortened post-anesthesia care unit stay(25±8 vs. 49±12 minutes,P<0.05),and a greater proportion of patients discharged within postoperative three days(57.5% vs. 35.0%,P<0.05).Conclusion Preoperative ultrasound-guided TAP block is an effective technique to improve postoperative analgesia and early recovery in patients undergoing retroperitoneoscopic urologic surgeries.

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.

CHANGES OF INTERLEUKIN-6 AND RELATED FACTORS AS WELL AS GASTRIC INTRAMUCOSAL pH DURING COLORECTAL AND ORTHOPAEDIC SURGICAL PROCEDURES

Objective To investigate the changes of perioperative serum levels of interleukin-6(IL-6), C-reactive protein (CRP), and cortisol, as well as gastric intramucosal pH (pHi) and plasma lactate, aiming to compare systemic changes and tissue perfusion during colorectal and orthopaedic surgical procedures. Methods Twenty patients were randomly assigned to two groups, 10 cases of operation on vertebral canal, 10 cases of colorectal radical operation.Venous blood was drawn at 1 day before operation, 2, 4, and 6 hours following skin incision, and 1 day after operation, in order to measure serum IL-6, CRP, and cortisol.pHi and plasma lactate were also measured at the same time points.Results Serum concentrations of IL-6 and cortisol increased gradually following operation, reaching the peak value at 6 hours from the beginning of operation.CRP was not detectable until the first day after operation.Peak concentration of IL-6 had positive relationship with CRP.These variables changed more significantly in colorectal group than that in orthopaedic group (P<0.05).pHi decreased gradually, reaching the lowest level at 4 hours from the beginning of operation, and to more extent in colorectal group than that in orthopaedic group (P<0.05).Conclusion IL-6 may reflect tissue damage more sensitively than CRP.Colorectal surgery might induce systemic disorder to more extent, in terms of immuno-endocrinal aspect as well as tissue perfusion, reflected with pHi.

Obesity paradox among elderly patients with coronary artery disease undergoing non-cardiac surgery

Background High body mass index （BMI） is a risk factor for chronic cardiac disease. However, mounting evidence supports that high BMI is associated with less risk of cardiac morbidity and mortality compared with normal BMI, also known as the obesity paradox. There- fore, we sought to determine the existence of the obesity paradox in regard to perioperative 30-day cardiac events among elderly Chinese patients with known coronary artery disease undergoing non-cardiac surgery. Methods A post-hoc analysis of a prospective, multi-institutional cohort study was performed. Patients aged 〉 60 years with a history of coronary artery disease and undergoing non-cardiac surgery were grouped according to BMI： underweight （〈 18.5 kg/m2）, normal weight （18.5-24.9 kg/m2）, overweight （25-29.9 kg/m2） and obese （≥ 30 kg/m2）. Demographic information, perioperative clinical variables and incidence of 30-day postoperative cardiac adverse event were retrieved from a research database. Results We identified 1202 eligible patients （BMI： 24.3 ± 3.8 kg/m2）. Across BMI groups, a U-shaped distribution pattern of incidence of 30-day postoperative major cardiac events was observed, with the lowest risk in the overweight group. When using the normal-weight group as a reference, no difference was found in either the obesity or overweight groups in terms of a major cardiac adverse event （MACE）. However, risk of a 30-day postoperative MACE was significantly higher in the underweight group （odds ratio [OR] 2.916, 95% confidence interval [CI]： 1.072-7.931, P = 0.036）. Conclusion Although not statistically significant, the U-shaped relation between BMI and cardiac complications indicates the obesity paradox possibly exists.

Using ketamine in a patient with a near-occlusion tracheal tumor undergoing tracheal resection and reconstruction: A case report

BACKGROUND Tracheal tumors may cause airway obstruction and pose a significant risk to ventilation and oxygenation.Due to its rarity,there is currently no established protocol or guideline for anesthetic management of resection of upper tracheal tumors,therefore individualized strategies are necessary.There are limited number of reports regarding the anesthesthetic management of upper tracheal resection and reconstruction(TRR)in the literature.We successfully used intravenous ketamine to manage a patient with a near-occlusion upper tracheal tumor undergoing TRR.CASE SUMMARY A 25-year-old female reported progressive dyspnea and hemoptysis.Bronchoscopy showed an intratracheal tumor located one tracheal ring below the glottis,which occluded>90%of the tracheal lumen.The patient was scheduled for TRR.Considering the risk of complete airway collapse after the induction of general anesthesia,we decided to secure the airway with a tracheostomy with spontaneous breathing.The surgeons needed to transect the trachea 1-2 cartilage rings below and above the tumor borders:a time-consuming process.Coughing and movement needed be minimized;thus,we added intravenous ketamine to local anesthetic infiltration.After tracheostomy,an endotracheal tube was placed into the distal trachea,and general anesthesia was induced.The surgeons resected four cartilage rings with the tumor attached and anastomosed the posterior tracheal wall.We performed a video-laryngoscopy to place a new endotracheal tube.Finally,the surgeons anastomosed the anterior tracheal walls.The patient was extubated uneventfully.CONCLUSION Ketamine showed great advantages in the anesthesia of upper TRR by providing analgesia with minimal respiratory depression or airway collapse.

Calpain Inhibitor Reduces Cancer-induced Bone Pain Possibly Through Inhibition of Osteoclastogenesis in Rat Cancer-induced Bone Pain Model

Background： Calpain, a calcium-dependent cysteine protease, has been demonstrated to regulate osteoclastogenesis, which is considered one of the major reasons for cancer-induced bone pain （CIBP）. In the present study, calpain inhibitor was applied in a rat CIBP model to determine whether it could reduce CIBP through regulation of osteoclastogenesis activity. Methods： A rat CIBP model was established with intratibial injection of Walker 256 cells. Then, the efficacy of intraperitoneal administered calpain inhibitor III （MDL28170, 1 mg/kg） on mechanical withdrawal threshold （MWT） of bilateral hind paws was examined on postoperative days （PODs） 2, 5, 8, 11, and 14. On POD 14, the calpain inhibitor＇s effect on tumor bone tartrate-resistant acid phosphatase （TRAP） stain and radiology was also carefully investigated. Results： Pain behavioral tests in rats showed that the calpain inhibitor effectively attenuated MWTs of both the surgical side and contralateral side hind paws on POD 5, 8, and 11 （P 〈 0.05）. TRAP-positive cell count of the surgical side bone was significantly decreased in the calpain inhibitor group compared with the vehicle group （P 〈 0.05）. However, bone resorption and destruction measured by radiographs showed no difference between the two groups. Conclusions： Calpain inhibitor can effectively reduce CIBP of both the surgical side and nonsurgical side after tumor injection in a rat CIBP model. It may be due to the inhibition of receptor activator of nuclear factor-kappa B ligand-induced osteoclastogenesis. Whether a calpain inhibitor could be a novel therapeutic target to treat CIBP needs further investigation.

A single-operator technique in ultrasound-guided regional anesthesia

During ultrasound-guided regional anesthesia,the operator typically holds the probe in one hand and the needle in the other hand.Meanwhile,another person is frequently needed to control the syringe.However,the availability of a-second-pair-of-hands could be challenging under many circumstances,such as operating room rush hours and off hours.In addition,an assistant,who is unfamiliar with the operator or the procedure,can make a seemingly short procedure a lengthy one,leading to delays or even adverse events due to miscommunication.There have been specialists come up with different solutions to solve this problem.[1-4]We developed a technique which allows a single operator to perform ultrasound-guided regional anesthesia.

Regional anesthesia and cancer recurrence in patients with late-stage cancer:a systematic review and meta-analysis

Background:Whether regional anesthesia may help to prevent disease recurrence in cancer patients is still controversial.The stage of cancer at the time of diagnosis is a key factor that defines prognosis and is one of the most important sources of heterogeneity for the treatment effect.We sought to update existing systematic reviews and clarify the effect of regional anesthesia on cancer recurrence in late-stage cancer patients.Methods:Medline,Embase,and Cochrane Library were searched from inception to September 2020 to identify randomized controlled trials(RCTs)and cohort studies that assessed the effect of regional anesthesia on cancer recurrence and overall survival(OS)compared with general anesthesia.Late-stage cancer patients were primarily assessed according to the American Joint Committee on Cancer Cancer Staging Manual(eighth edition),and the combined hazard ratio(HR)from random-effects models was used to evaluate the effect of regional anesthesia.Results:A total of three RCTs and 34 cohort studies(including 64,691 patients)were identified through the literature search for inclusion in the analysis.The risk of bias was low in the RCTs and was moderate in the observational studies.The pooled HR for recurrence-free survival(RFS)or OS did not favor regional anesthesia when data from RCTs in patients with late-stage cancer were combined(RFS,HR=1.12,95%confidence interval[CI]:0.58-2.18,P=0.729,I2=76%;OS,HR=0.86,95%CI:0.63-1.18,P=0.345,I^(2)=48%).Findings from observational studies showed that regional anesthesia may help to prevent disease recurrence(HR=0.87,95%CI:0.78-0.96,P=0.008,I2=71%)and improve OS(HR=0.88,95%CI:0.79-0.98,P=0.022,I^(2)=79%).Conclusions:RCTs reveal that OS and RFS were similar between regional and general anesthesia in late-stage cancers.The selection of anesthetic methods should still be based on clinical evaluation,and changes to current practice need more support from large,well-powered,and well-designed studies.

Difficult Airway for Patients Undergoing Spine Surgeries

INTRODUCTION The “cannot intubate, cannot ventilate” situation although rare is a nightmare for anesthesiologists. Difficult airway is defined as difficult facemask or supraglottic airway （SGA） ventilation, difficult SGA placement, laryngoscopy, tracheal intubation, or failed intubation. We presented three cases of difficult airway and their airway management.

Potential Effect of Preoperative Immunotherapy on Anesthesia of Patients with Anti-N-methyI-D-aspartate Receptor Encephalitis

Anti-N-methyl-D-aspartate receptor （anti-NMDA-R） encephalitis is a newly recognized neuro-autoimmune disease. Patients usually present with a series of neurological and psychiatric syndromes including memory impairment, seizures, dyskinesia, autonomic nervous system dysfunction, etc. Anti-NMDA-R encephalitis usually affects young women with teratoma being a common co-existing condition in nearly 47% of the diagnosed patients. Previous studies have shown that teratoma removal, being the current first-line therapy, may enhance the effectiveness of autoimmune therapy and decrease the incidence of relapse, However, poorly controlled encephalitis poses as a perioperative anesthetic risk. Therefore, timing of the surgery is of great concern and is a question yet to be answered. Due to low incidence of anti-NMDA-R encephalitis in general population, literature of the perioperative management in these group of patients is scarce. Only few case reports were found yet, none has discussed the issue of surgery timing. In this study, 6 patients with anti-NMDA-R encephalitis undergoing teratoma removal were reviewed, and timing of surgery and anesthetic management for these patients were discussed.

Remote video lecture education improves anesthesiology residency training in Tibet of China

To the Editor:The Qinghai-Tibet Plateau,called the roof of the world,is an extremely harsh environment with scarce medical resources.[1]After the founding of the People’s Republic of China,the Chinese government has invested a lot of financial support to develop Tibet Autonomous Region and to improve the quality of healthcare.The life expectancy of the whole district has increased from 36 years old in the 1950s to 68 years old currently,and the population has grown from less than 1 million in the 1950s to 3.31 million today.

RELAXED ASYNCHRONOUS ITERATIONS FOR THE LINEAR COMPLEMENTARITY PROBLEM

Presents a class of relaxed asynchronous parallel multisplitting iterative methods for solving the linear complementarity problem on multiprocessor systems. Establishment of the methods; Convergence theories; Numerical results.

Author＇s Reply to the Letter to Editor “Difficult Airway Management： Correct Concepts and Algorithm are Important for Patient Safety”

For the three cases listed in this article, difficult airway was anticipated preoperatively. We described how we intubated, but it did not mean what we did was the best choice.