Artificial intelligence model predicting postoperative pain using facial expressions: a pilot study

PURPOSE

This study aimed to assess whether an artificial intelligence model based on facial expressions can accurately predict significant postoperative pain.

METHODS

A total of 155 facial expressions from patients who underwent gastric cancer surgery were analyzed to extract facial action units (AUs), gaze, landmarks, and positions. These features were used to construct various machine learning (ML) models, designed to predict significant postoperative pain intensity (NRS ≥ 7) from less significant pain (NRS < 7). Significant AUs predictive of NRS ≥ 7 were determined and compared to AUs known to be associated with pain in awake patients. The area under the receiver operating characteristic curves (AUROCs) of the ML models was calculated and compared using DeLong's test.

RESULTS

AU17 (chin raising) and AU20 (lip stretching) were found to be associated with NRS ≥ 7 (both P ≤ 0.004). AUs known to be associated with pain in awake patients did not show an association with pain in postoperative patients. An ML model based on AU17 and AU20 demonstrated an AUROC of 0.62 for NRS ≥ 7, which was inferior to a model based on all AUs (AUROC = 0.81, P = 0.006). Among facial features, head position and facial landmarks proved to be better predictors of NRS ≥ 7 (AUROC, 0.85-0.96) than AUs. A merged ML model that utilized gaze and eye landmarks, as well as head position and facial landmarks, exhibited the best performance (AUROC, 0.90) in predicting significant postoperative pain.

CONCLUSION

ML models using facial expressions can accurately predict the presence of significant postoperative pain and have the potential to screen patients in need of rescue analgesia.

TRIAL REGISTRATION NUMBER

This study was registered at ClinicalTrials.gov (NCT05477303; date: June 17, 2022).

Machine learning model of facial expression outperforms models using analgesia nociception index and vital signs to predict postoperative pain intensity: a pilot study

BACKGROUND

Few studies have evaluated the use of automated artificial intelligence (AI)-based pain recognition in postoperative settings or the correlation with pain intensity. In this study, various machine learning (ML)-based models using facial expressions, the analgesia nociception index (ANI), and vital signs were developed to predict postoperative pain intensity, and their performances for predicting severe postoperative pain were compared.

METHODS

In total, 155 facial expressions from patients who underwent gastrectomy were recorded postoperatively; one blinded anesthesiologist simultaneously recorded the ANI score, vital signs, and patient self-assessed pain intensity based on the 11-point numerical rating scale (NRS). The ML models' area under the receiver operating characteristic curves (AUROCs) were calculated and compared using DeLong's test.

RESULTS

ML models were constructed using facial expressions, ANI, vital signs, and different combinations of the three datasets. The ML model constructed using facial expressions best predicted an NRS ≥ 7 (AUROC 0.93) followed by the ML model combining facial expressions and vital signs (AUROC 0.84) in the test-set. ML models constructed using combined physiological signals (vital signs, ANI) performed better than models based on individual parameters for predicting NRS ≥ 7, although the AUROCs were inferior to those of the ML model based on facial expressions (all P < 0.050). Among these parameters, absolute and relative ANI had the worst AUROCs (0.69 and 0.68, respectively) for predicting NRS ≥ 7.

CONCLUSIONS

The ML model constructed using facial expressions best predicted severe postoperative pain (NRS ≥ 7) and outperformed models constructed from physiological signals.

Neuroprotective effect of erythropoietin on anesthesia-induced neurotoxicity through the modulation of autophagy in Caenorhabditis elegans

Background

The anti-oxidative, anti-inflammatory, and anti-apoptotic effects of erythropoietin may provide neuroprotective effects. Erythropoietin also modulates autophagy signaling that may play a role in anesthesia-induced neurotoxicity (AIN). Herein, we investigated whether AIN can be attenuated by the neuroprotective effect of erythropoietin in the Caenorhabditis elegans (C. elegans).

Methods

Synchronized worms were divided into the control, Iso, EPO, and EPO-Iso groups. The chemotaxis index (CI) was evaluated when they reached the young adult stage. The lgg-1::GFP-positive puncta per seam cell were used to determine the autophagic events. The erythropoietin-mediated pathway of autophagy was determined by measuring the genetic expression level of let-363, bec-1, atg-7, atg-5, and lgg-3.

Results

Increased lgg-1::GFP puncta were observed in the Iso, EPO, and EPO-Iso groups. In the Iso group, only the let-363 level decreased significantly as compared to that in the control group (P = 0.009). bec-1 (P < 0.001), atg-5 (P = 0.012), and lgg-3 (P < 0.001) were expressed significantly more in the EPO-Iso group than in the Iso groups. Repeated isoflurane exposure during development decreased the CI. Erythropoietin could restore the decreased CI by isoflurane significantly in the EPO-Iso group.

Conclusion

Erythropoietin showed neuroprotective effects against AIN and modulated the autophagic pathway in C. elegans. This experimental evidence of erythropoietin-related neuroprotection against AIN may be correlated with the induced autophagic degradation process that was sufficient for handling enhanced autophagy induction in erythropoietin-treated worms.

Reduced side effects and improved pain management by continuous ketorolac infusion with patient-controlled fentanyl injection compared with single fentanyl administration in pelviscopic gynecologic surgery: a randomized, double-blind, controlled study

BACKGROUND

A combination of opioids and adjunctive drugs can be used for intravenous patient-controlled analgesia (PCA) to minimize opioid-related side effects. We investigated whether two different analgesics administered separately via a dual-chamber PCA have fewer side effects with adequate analgesia than a single fentanyl PCA in gynecologic pelviscopic surgery.

METHODS

This prospective, double-blind, randomized, and controlled study included 68 patients who underwent pelviscopic gynecological surgery. Patients were allocated to either the dual (ketorolac and fentanyl delivered by a dual-chamber PCA) or the single (fentanyl alone) group. Postoperative nausea and vomiting (PONV) and analgesic quality were compared between the two groups at 2, 6, 12, and 24 h postoperatively.

RESULTS

The dual group showed a significantly lower incidence of PONV during postoperative 2-6 h (P = 0.011) and 6-12 h (P = 0.009). Finally, only two patients (5.7%) in the dual group and 18 (54.5%) in the single group experienced PONV during the entire postoperative 24 h and could not maintain intravenous PCA (odds ratio: 0.056, 95% CI [0.007, 0.229], P < 0.001). Despite the administration of less fentanyl via intravenous PCA during the postoperative 24 h in the dual group than in the single group (66.0 ± 77.8 vs. 383.6 ± 70.1 μg, P < 0.001), postoperative pain had no significant intergroup difference.

CONCLUSIONS

Two different analgesics, continuous ketorolac and intermittent fentanyl bolus, administered via dual-chamber intravenous PCA, showed fewer side effects with adequate analgesia than conventional intravenous fentanyl PCA in gynecologic patients undergoing pelviscopic surgery.

Comparison of the Effect of Landmark-Based Midline and Paramedian Approaches on Spinal Anesthesia-Related Complications in Adult Patients: A Meta-Analysis of Randomized Controlled Trials

Background and Objectives: Spinal anesthesia is widely used in various types of surgery. However, several complications can occur afterward. This study aimed to identify differences in the incidence of anesthesia-related complications according to the approach methods (midline versus paramedian) for landmark-based spinal anesthesia. Materials and Methods: We searched electronic databases, including PubMed, EMBASE, CENTRAL, Scopus, and Web of Science, for eligible randomized controlled trials. The primary outcome was post-dural puncture headache (PDPH) incidence, and secondary outcomes were low back pain (LBP) incidence and success rate in the first trial of spinal anesthesia. We estimated the odds ratio (OR) with 95% confidence intervals (CI) using a random-effects model. Results: In total, 2280 patients from 13 randomized controlled trials were included in the final analysis. The incidence rates of PDPH were 5.9% and 10.4% in the paramedian and midline approach groups, respectively. The pooled effect size revealed that the incidence of PDPH (OR: 0.43, 95% CI [0.22-0.83]; p = 0.01; I2 = 53%) and LBP (OR: 0.27, 95% CI [0.16-0.44]; p < 0.001; I2 = 16%) decreased, and the success rate in the first attempt was higher (OR: 2.30, 95% CI [1.36-3.87]; p = 0.002; I2 = 35%) with the paramedian than with the midline approach. Conclusions: Paramedian spinal anesthesia reduced PDPH and LBP and increased the success rate of the first attempt.

Postoperative analgesic effects of the quadratus lumborum block in pediatric patients: a systematic review and meta-analysis

Background

This study assessed the postoperative analgesic efficacy and safety of the quadratus lumborum block (QLB) in pediatric patients.

Methods

Electronic databases were searched for studies comparing the QLB to conventional analgesic techniques in pediatric patients. The primary outcome was the need for rescue analgesia 12 and 24 hours after surgery. Secondary outcomes covered the Face-Legs-Activity-Cry-Consolability Scale (FLACC) scores at various time points; parental satisfaction; time to the first rescue analgesia; hospitalization time; block execution time; block failure rates, and adverse events.

Results

Sixteen randomized controlled trials were analyzed involving 1,061 patients. The QLB significantly reduced the need for rescue analgesia both at 12 and 24 hours after surgery (12 hours, relative risk [RR]: 0.45; 95% confidence interval [CI]: 0.01, 0.88; 24 hours, RR: 0.51; 95% CI: 0.31, 0.70). In case of 24 hours after surgery, type 1 QLB significantly reduced the need for rescue analgesia (RR: 0.56; 95% CI: 0.36, 0.76). The QLB also exhibited lower FLACC scores at 1 hour (standardized mean difference [SMD]: -0.87; 95% CI: -1.56, -0.18) and 6 hours (SMD: -1.27; 95% CI: -2.33, -0.21) following surgery when compared to non-QLB. Among QLBs, type 2 QLB significantly extended the time until the first rescue analgesia (SMD: 1.25; 95% CI: 0.84, 1.67). No significant differences were observed in terms of parental satisfaction, hospitalization time, block execution time, block failure, or adverse events between QLB and non-QLB groups.

Conclusions

The QLB provides non-inferior analgesic efficacy and safety to conventional methods in pediatric patients.

Effects of remimazolam combined with remifentanil on quality of recovery after ambulatory hysteroscopic surgery: a prospective, observational study

BACKGROUND

Remimazolam, a new benzodiazepine, is known for its quick onset of effects and recovery time. Recently, it has been licensed for general anesthesia and sedation in Korea and its use is increasing in other countries. However, less is known about its effect on postoperative recovery. We used a patient-reported outcome questionnaire to examine the effect of remimazolam on postoperative recovery.

METHODS

Patients who underwent hysteroscopy on day surgery basis were administered an induction dose of remimazolam 6 mg/kg/h followed by a maintenance dose of 1-2 mg/kg/h. After surgery, the translated Korean version of 15-item Quality of Recovery scale (QoR-15K) including post-discharge nausea and vomiting (PDNV) and/or pain, was surveyed 24 h after surgery to evaluate patient recovery.

RESULTS

Total of 38 patients were enrolled in this prospective, observational study. All patients successfully completed QoR-15K. Only one patient scored low for moderate pain and PDNV. On average, patients scored 9 and above for all QoR-15K items except for moderate pain (8.66 ± 1.68). When QoR-15K items were grouped into dimensions, all dimensions scored an average of 9 or higher on a 10-point scale. In addition, 19 out of 38 patients gave score range of 148 to 150 out of possible 150.

CONCLUSIONS

Psychometric evaluation based on postoperative QoR-15K among patients receiving remimazolam shows satisfactory patient recovery profiles without significant pain or PDNV. Considering its effectiveness and safety, remimazolam could be one of useful agents for general anesthesia of day surgery in terms of postoperative recovery.

The Impact of Regional Nerve Blocks on Postoperative Delirium or Cognitive Dysfunction following Thoracic Surgery: A Systematic Review and Meta-Analysis

Regional nerve blocks (NBs) mitigate the occurrence of postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) in adult patients undergoing thoracic surgery. This study aimed to determine the exact effect of NBs on POCD and POD. Electronic databases, including PubMed, EMBASE, CINAHL, Scopus, and Web of Science, were searched for studies. The primary outcome was the incidence of POD or POCD. The secondary outcome was pain scores assessed 24 and 48 h postoperatively. We calculated the log odds ratio (LOR) and standardized mean difference (SMD) with 95% confidence intervals (CIs). The LOR was converted to an odds ratio (OR). In the analysis of 1010 patients from seven randomized controlled trials, POD and POCD rates were 14.1% and 16.7%, respectively, in the NB group, and higher, at 27.3% and 35.2%, in the control group. NBs reduced the incidence of POD (OR, 0.44; 95%CI 0.30 to 0.64; p < 0.001; I2 = 0.00%) and POCD (OR, 0.43; 95%CI 0.24 to 0.76; p < 0.001; I2 = 0.00%). NBs reduced pain scores at 24 h (SMD, -2.60; 95%CI -3.90 to -1.30, p < 0.001; I2 = 97.68%) and 48 h (SMD, -1.80; 95%CI -3.18 to -0.41, p = 0.01; I2 = 98.14%) postoperatively. NBs mitigated the occurrence of POD and POCD in adult patients after thoracic surgery.

The effect of intranasal dexmedetomidine administration on emergence agitation or delirium in pediatric patients after general anesthesia: A meta-analysis of randomized controlled trials

BACKGROUND

Emergence agitation or delirium can occur in pediatric patients after anesthesia. Dexmedetomidine is known to reduce the impairment of postoperative cognitive function.

AIMS

This study aimed to identify the role of intranasal administration of dexmedetomidine in lowering the development of emergence agitation or emergence delirium in pediatric patients after general anesthesia.

METHODS

Electronic databases, including PubMed, EMBASE, CENTRAL, Scopus, and Web of Science, were searched to identify studies. The primary outcome was the proportion of patients who underwent emergence agitation or emergence delirium after the surgery. Secondary outcomes included emergence time and incidence of postoperative nausea and/or vomiting. We estimated the odds ratio and mean difference with 95% confidence intervals for the determination of effect size using a random-effects model.

RESULTS

In total, 2103 pediatric patients from 20 randomized controlled trials were included in the final analysis. The incidence of emergence agitation or emergence delirium was 13.6% in the dexmedetomidine group and 33.2% in the control group. The pooled effect size revealed that intranasal dexmedetomidine administration significantly reduced the incidence of postoperative emergence agitation or emergence delirium in pediatric patients undergoing surgery under general anesthesia (odds ratio 0.25, 95% confidence interval 0.18-0.34; p = .0000; I²  = 37.74%). Additionally, significant difference was observed in emergence time between the two groups (mean difference 2.42, 95% confidence interval 0.37-4.46; p = .021; I²  = 98.40%). Children in the dexmedetomidine group had a significantly lower incidence of postoperative nausea and/or vomiting than those in the control group (odds ratio 0.39, 95% confidence interval 0.24-0.64; p = .0002; I²  = 0.00%).

CONCLUSIONS

Intranasal dexmedetomidine reduced the incidence of emergence agitation or emergence delirium in pediatric patients after general anesthesia.

Ultrasound assessment of residual gastric volume in older adults undergoing staged-bilateral total knee arthroplasty after consuming carbohydrate-containing fluids: a prospective observational study

BACKGROUND

We compared preoperative residual gastric volume (GV) between the first and second stages of total knee arthroplasty (TKA) in older adults after drinking carbohydrate-containing fluid 2 h prior to surgery.

METHODS

In this study, 36 patients, aged > 65 years, scheduled for staged bilateral TKA with one-week interval, were enrolled. The patients consumed 400 ml of carbohydrate-containing fluid 2 h prior to surgery. Before the induction of spinal anesthesia, the gastric antral cross-sectional area was measured at the first and second TKA using ultrasound, and the residual GV was calculated. The primary outcome was the residual GV. Qualitative GV (grades 0, 1, and 2) and analgesic consumption after the first TKA were assessed as secondary outcomes.

RESULTS

The GV (median [Q1, Q3]) was greater in the second-stage TKA (41.1 [22.5, 62.8] ml) than in the first-stage TKA (10.3 [0.0, 27.1] ml) (P < 0.001). In the qualitative assessment, the distribution was not different between the two stages of TKA (P = 0.219) and only one patient showed grade 2 gastric content in the second TKA. When opioid consumption was converted to an equivalent dose of morphine, an average of 53.9 mg of morphine was required after the first TKA.

CONCLUSIONS

Residual GV after drinking carbohydrate-containing fluid differed according to the stage of TKA, showing a larger residual GV in the second TKA than in the first one. In older adults scheduled to undergo bilateral staged TKA, caution is required in preoperative fasting practice, especially in second-stage surgery.

The Effect of Peripheral Nerve Block on Postoperative Delirium in Older Adults Undergoing Hip Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This meta-analysis aimed to determine whether peripheral nerve blocks (PNB) reduce postoperative delirium (POD) in elderly patients undergoing hip surgery. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022328320). The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for randomized controlled trials (RCTs) on 26 April 2022. A total of 19 RCTs with 1977 participants were included. Perioperative PNB lowered the POD incidence on the third postoperative day (OR: 0.59, 95% CI [0.40 to 0.87], p = 0.007, I² = 35%), in patients without underlying cognitive impairment (OR: 0.47, 95% CI [0.30 to 0.74], p = 0.001, I² = 30%), and when a fascia iliaca compartment block (OR: 0.58, 95% CI [0.37 to 0.91], p = 0.02, I² = 0%) or a femoral nerve block (OR: 0.33, 95% CI [0.11 to 0.99], p = 0.05, I² = 66%) were performed. The pain score was also reduced (SMD: -0.83, 95% CI [-1.36 to -0.30], p = 0.002, I² = 95%) after PNB. Perioperative PNB can lower the POD incidence and pain scores up to the third postoperative day. However, considering the wide variety of PNBs performed, more trials are needed to identify the effects of each PNB on POD.

Change in glottic view during intubation using a KoMAC videolaryngoscope: A retrospective analysis

Intubation with videolaryngoscopy has become popular in various clinical settings. However, despite the use of a videolaryngoscope, difficult intubation still exists and intubation failure has been reported. This retrospective study assessed the efficacy of the 2 maneuvers in improving the glottic view during videolaryngoscopic intubation. The medical records of patients who underwent videolaryngoscopic intubation and whose glottal images were stored in electronic medical charts were reviewed. The videolaryngoscopic images were divided into 3 categories according to the applied optimization techniques as follows: conventional method, with the blade tip located in the vallecular; backward-upward-rightward pressure (BURP) maneuver; and epiglottis lifting maneuver. Four independent anesthesiologists scored the visualization of the vocal folds using the percentage of glottic opening (POGO, 0-100%) scoring system. A total of 128 patients with 3 laryngeal images were analyzed. The glottic view was the most improved in the epiglottis lifting maneuver among all the techniques. The median POGO scores were 11.3, 36.9, and 63.1 in the conventional method, BURP, and epiglottis lifting maneuver, respectively (P < .001). There were significant differences in the distribution of POGO grades according to the application of BURP and epiglottis lifting maneuvers. In the POGO grades 3 and 4 subgroups, the epiglottis lifting maneuver was more effective than the BURP maneuver in improving the POGO score Inadequate visualization of the vocal folds occurred even when intubation was performed using a videolaryngoscope. The application of optimization maneuvers, such as BURP and epiglottis lifting by the blade tip, could improve the glottic view.

Intraoperative 5-HT3 receptor antagonists decrease the prevalence of postoperative delirium in older adults undergoing hip fracture surgery: a single-center retrospective study

PURPOSE

Postoperative delirium (POD) occurs commonly in older adults, resulting in unfavorable outcomes. Several recent clinical studies have suggested that 5-hydroxytryptamine 3 (5-HT₃) receptor antagonists can treat and prevent POD. In this retrospective study, the association between 5-HT₃ receptor antagonists and POD was investigated in older adults who underwent hip fracture surgery.

METHODS

The electronic medical records of older adults aged ≥ 65 years who underwent hip fracture surgery between January 2011 and June 2018 were reviewed retrospectively. Multivariable logistic regression analysis was used to investigate the association between 5-HT₃ receptor antagonists and the occurrence of POD. In addition to the incidence of POD, anesthesia-, surgery-, and patient-related factors related to POD were evaluated.

RESULTS

Of the 1025 patients included, 813 (79.3%) were administered 5-HT₃ receptor antagonists intraoperatively; 471 (45.9%) were administered ramosetron, and 342 (33.4%) were administered palonosetron. POD was identified in 242 patients (23.6%). Ramosetron and palonosetron reduced the POD incidence by 53% (odds ratio [OR] 0.47; 95% confidence interval [CI] 0.32‒0.71; P < 0.001) and 41% (OR 0.59; 95% CI 0.39‒0.89; P = 0.011), respectively. Additionally, age, American Society of Anesthesiologists physical status class 4, and male were confirmed as risk factors for POD.

CONCLUSION

Intraoperative 5-HT₃ receptor antagonists may be associated with a reduced risk of POD and can be considered one of the preventive strategies for POD in older adults undergoing hip fracture surgery.

Postoperative Delirium after Dexmedetomidine versus Propofol Sedation in Healthy Older Adults Undergoing Orthopedic Lower Limb Surgery with Spinal Anesthesia: A Randomized Controlled Trial

BACKGROUND

Delirium is a critical postoperative complication in older patients. Based on the hypothesis that intraoperative dexmedetomidine sedation would lower postoperative delirium than propofol sedation would, the authors compared the incidence of postoperative delirium in older adults, using the mentioned sedatives.

METHODS

This double-blinded, randomized controlled study included 748 patients, aged 65 yr or older, who were scheduled for elective lower extremity orthopedic surgery, between June 2017 and October 2021. Patients were randomized equally into two groups in a 1:1 ratio according to the intraoperative sedative used (dexmedetomidine vs. propofol). The postoperative delirium incidence was considered the primary outcome measure; it was determined using the confusion assessment method, on the first three postoperative days. The mean arterial pressure and heart rate were evaluated as secondary outcomes.

RESULTS

The authors enrolled 732 patients in the intention-to-treat analyses. The delirium incidence was lower in the dexmedetomidine group than in the propofol group (11 [3.0%] vs. 24 [6.6%]; odds ratio, 0.42; 95% CI, 0.201 to 0.86; P = 0.036). During sedation, the mean arterial pressure (median [interquartile range] mmHg) was higher in the dexmedetomidine group (77 [71 to 84]) than in the propofol group (74 [69 to 79]; P < 0.001); however, it significantly fell lower (74 [68 to 80]) than that of the propofol group (80 [74 to 87]) in the postanesthesia care unit (P < 0.001). Lower heart rates (beats/min) were recorded with the use of dexmedetomidine than with propofol, both during sedation (60 [55 to 66] vs. 63 [58 to 70]) and in the postanesthesia care unit (64 [58 to 72] vs. 68 [62-77]; P < 0.001).

CONCLUSIONS

Dexmedetomidine showed a lower incidence of postoperative delirium than propofol in healthy older adults undergoing lower extremity orthopedic surgery.

EDITOR’S PERSPECTIVE

Effect of the Paravertebral Block on Chronic Postsurgical Pain After Thoracic Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

This study aimed to identify the benefits of thoracic paravertebral block (PVB) by focusing on its role in reducing chronic postsurgical pain (CPSP) after thoracic surgery.

DESIGN

A systematic review and meta-analysis of randomized controlled trials (RCTs).

SETTING

Electronic databases, including PubMed, EMBASE, CENTRAL, Scopus, and Web of Science, were searched to identify studies.

PARTICIPANTS

Patients undergoing thoracic surgeries.

INTERVENTION

Paravertebral block for postoperative analgesia.

MEASUREMENT AND MAIN RESULTS

A total of 1,028 adult patients from 10 RCTs were included in the final analysis. The incidence of CPSP at 3 months after surgery was not reduced in the PVB group compared with the no-block (odds ratio [OR] 0.59, 95% CI 0.34-1.04; p = 0.07; I² = 6.96%) and other-block (OR 1.39, 95% CI 0.30-6.42; p = 0.67; I² = 77.75%) groups. The PVB did not significantly reduce the incidence of CPSP after 6 months from surgery when compared with no block (OR 0.44, 95% CI 0.08-2.53; p = 0.36; I² = 87.53%) and other blocks (OR 1.17, 95% CI 0.71-1.95; p = 0.93; I² = 45.75%). The PVB significantly decreased postoperative pain at 24 and 48 hours at rest compared with the no- block group. The pain score was higher in the PVB group than in the other block groups 48 hours after surgery at rest.

CONCLUSIONS

Thoracic PVB does not prevent CPSP after thoracic surgery. Further large RCTs are required to confirm and validate the authors' results.

Ultrasound assessment of gastric volume in older adults after drinking carbohydrate-containing fluids: a prospective, nonrandomized, and noninferiority comparative study

PURPOSE

The aim of this study was to evaluate the safety of drinking carbohydrate-containing fluids two hours prior to surgery in older adults using ultrasonography.

METHODS

We conducted a nonrandomized and noninferiority comparative study in 60 patients aged over 65 yr who were scheduled for total knee arthroplasty. Patients who were fasted from midnight (fasting group) or who drank 400 mL of a carbohydrate-containing fluid (carbohydrate ingestion group) two hours prior to surgery were matched for age, sex, and body mass index. We measured the cross-sectional area (CSA) of gastric antrum using ultrasound and estimated the gastric fluid volume as the study's primary outcome measure. The noninferiority margin (δ) for the mean difference was predefined as 50 mL. The secondary outcome measures included CSA of the antrum and qualitative gastric volume.

RESULTS

The mean (standard deviation) gastric volume was not significantly different between the fasting group and the carbohydrate ingestion group (30.2 [25.4] mL vs 28.4 [35.8] mL; each group, n = 30; P = 0.81). The mean difference in gastric volume was -1.9 mL (95% confidence interval [CI], -17.9 to 14.2), and the upper limit of the 95% CI was lower than the prespecified noninferiority limit (δ = 50 mL). Secondary outcomes were not significantly different between the two groups.

CONCLUSION

Drinking of carbohydrate-containing fluid two hours prior to surgery was noninferior to overnight fasting with respect to residual gastric volume at induction of anesthesia in healthy older adults who undergoing total knee arthroplasty.

STUDY REGISTRATION

ClinicalTrials.gov (NCT04514380); registered 14 August 2020.

Total intravenous anesthesia induced and maintained by a combination of remimazolam and remifentanil without a neuromuscular blocking agent: a prospective, observational pilot study

Background

A novel short-acting benzodiazepine, Remimazolam, has recently been approved for general anesthesia and sedation. Hence, we investigated the feasibility and safety of remimazolam during the induction and maintenance of general anesthesia without using a neuromuscular blocking agent (NMBA) in patients undergoing hysteroscopic surgery.

Methods

This prospective observational study included 38 patients undergoing hysteroscopic surgery. Remimazolam and remifentanil were the main anesthetic agents without an NMBA, and a supraglottic airway was inserted to protect the airway. The induction time, amount of each anesthetic agent used during anesthesia, intraoperative bispectral index (BIS) hemodynamic parameters, and recovery profiles were measured.

Results

General anesthesia was successfully administered to 37 patients using remimazolam and remifentanil without NMBA. The induction doses of remimazolam and remifentanil were 0.4 mg/kg (interquartile range [IQR] 0.34–0.47 mg/kg) and 1.07 μg/kg (IQR, 0.90–1.29 μg/kg), respectively. Additionally, the maintenance doses of remimazolam and remifentanil were 1.14 mg/kg/h (IQR, 0.88–1.55 mg/kg/h) and 0.06 μg/kg/min (IQR, 0.04–0.08 μg/kg/min), respectively. Intraoperative BIS values had risen temporarily > 60 in eight patients (21.6%) despite administration of 2 mg/kg/h of remimazolam; thus, they were treated with supplementary midazolam. The median recovery time was 7 min (IQR, 5–8 min) after 40 min (IQR, 40.0–57.5 min) of total mean anesthesia time. There was no correlation between the infusion dose of remimazolam and recovery profiles, such as recovery time, final BIS of anesthesia, modified observer assessment of alertness/sedation (OAA/S) scale or post-anesthesia recovery (PAR) score when arriving at the PACU, and length of stay in the PACU (all P > 0.05).

Conclusion

Remimazolam can be combined with remifentanil without an NMBA in female patients who undergo hysteroscopic surgery, during which a supraglottic airway is a feasible method to protect the airway.

Trial registration

The study protocol was registered at ClinicalTrials.gov (NCT05025410) on 27/08/2021.

5-HT3 receptor antagonists decrease the prevalence of postoperative delirium in older patients undergoing orthopedic lower limb surgery

BACKGROUND

Delirium is an important postoperative complication. Recent research suggested that 5-hydroxytryptamine 3 (5-HT₃) receptor antagonists may have clinical effect in the treatment and prevention of delirium. We investigated the association between 5-HT₃ receptor antagonists and the occurrence of postoperative delirium (POD).

METHODS

Retrospectively, the electronic medical records were reviewed in patients aged ≥ 65 years who underwent orthopedic lower limb surgery under regional anesthesia (spinal or combined spinal-epidural anesthesia) and administered intravenous 0.075 mg palonosetron or 0.3 mg ramosetron prior to the end of surgery between July 2012 and September 2015. POD incidence and anesthesia-, surgery-, and patient-related factors were evaluated. To investigate the association between 5-HT₃ receptor antagonists and the occurrence of POD, multivariable logistic regression analysis was performed.

RESULTS

Of the 855 patients included, 710 (83%) were administered 5-HT₃ receptor antagonists. POD was confirmed in 46 (5.4%) patients. 5-HT₃ receptor antagonists reduced the POD incidence by 63% (odds ratio [OR] 0.37; 95% confidence interval [CI], 0.15-0.94; P = 0.04). Moreover, the POD incidence decreased by 72% (OR 0.28, 95% CI 0.10-0.77, P = 0.01) when palonosetron was administered. Other identified risk factors for POD were emergency surgery, older age, hip surgery, lower body mass index, and intraoperative propofol sedation.

CONCLUSION

5-HT₃ receptor antagonists may be related with a significantly reduced risk for POD in older patients undergoing orthopedic lower limb surgery. Notably, palonosetron was more effective for POD prevention.

Efficacy of quadratus lumborum block for analgesia in adult participants undergoing hip surgery: A meta-analysis of randomized controlled trials

STUDY OBJECTIVE

This study aimed to identify the benefits of quadratus lumborum block (QLB) in terms of postoperative analgesic effects in adult participants undergoing hip surgery.

DESIGN

Meta-analysis of randomized controlled trials.

SETTING

Previous randomized controlled trials that evaluated the analgesic effect of QLB compared to that of no block.

PATIENTS

Nine studies including 616 participants.

INTERVENTIONS

Participants in the treatment group received QLB, whereas those in the control group received no block.

MEASUREMENTS

Outcomes were postoperative 24-h opioid consumption (primary), 12-h/24-h visual analog scale (VAS) or numeric rating scale (NRS) pain scores, postoperative nausea and vomiting (PONV), and satisfaction. The effect size was estimated using the standardized mean difference (SMD), mean difference (MD), or risk ratio (RR) with a 95% confidence interval (CI). We used the risk of bias tool (RoB 2) to assess the risk of bias of the included studies and the GRADE approach to determine the level of certainty of the evidence.

MAIN RESULTS

Compared to no block, the QLB group has less opioid consumption (SMD -1.69, 95% CI -2.54 to -0.84; low level of certainty of the evidence). Estimated MD for morphine consumption was 24 mg. The QLB group had a lower 12-h VAS/NRS pain score (MD -1.16, 95% CI -1.82 to -0.51; moderate level of certainty of the evidence) and 24-h VAS/NRS pain score (MD -0.92, 95% CI -1.42 to -0.43; moderate level of certainty of the evidence). QLB decreased the incidence of PONV (RR 0.43, 95% CI 0.24 to 0.79; moderate level of certainty of the evidence) and increased participants' satisfaction (SMD 1.15, 95% CI 0.63 to 1.67; moderate level of certainty of the evidence). Estimated MD for satisfaction was 1.74 points of Likert scale. There were no significant adverse events associated with the QLB in any of the included trials.

CONCLUSION

Our meta-analysis showed that QLB when compared to no block clinically decreased opioid requirements, reduced PONV, and improved participants' satisfaction. QLB also seems to be significantly superior to no block in terms of pain score, but its clinical importance remains unclear.

Immediate retrograde amnesia induced by midazolam: A prospective, non-randomised cohort study

BACKGROUND

Midazolam, a short-acting benzodiazepine, has sedative, anxiolytic, amnestic and anticonvulsant effects. Given its advantages of rapid onset, short duration and low toxicity, midazolam is optimal for any procedural sedation. Midazolam is known to cause anterograde amnesia; however, the possibility of retrograde amnesia has also been raised. This prospective cohort, non-randomised study evaluated the presence and extent of retrograde amnesia induced by midazolam during caesarean delivery.

METHODS

One hundred parturients scheduled for elective caesarean delivery under spinal anaesthesia were enrolled. As soon as giving birth, six picture cards were shown to the patients in 1-min intervals, and then midazolam (0.1 mg/kg) was given or not according to the patients' preference. This overall retrograde recall rate of six cards was the primary outcome of our study, which was asked by a blinded investigator.

RESULTS

The overall retrograde card recall rate was lower in the midazolam group compared with the control group (77.0 ± 13.4 vs. 87.7 ± 3.9%, P < .001), especially at 1 minute before midazolam administration (58% vs. 88%, P < .001). Decreased memory trend was observed as time progressed towards midazolam administration in the midazolam group (P = .035). More patients answered 'yes' to the factitious event in the midazolam group than in the control group (26% vs. 4%, P = .004).

CONCLUSION

Intravenous midazolam could cause a brief-period retrograde amnesia in visual and event memory. Moreover, there were more spurious reports of intraoperative factitious events in the midazolam group, implying that episodic memories were also affected by midazolam.

Immediate retrograde amnesia induced by midazolam: a prospective, nonrandomized cohort study

BACKGROUND

Midazolam, a short-acting benzodiazepine, has sedative, anxiolytic, amnestic, and anticonvulsant effect. Given its advantages of rapid onset, short duration, and low toxicity, midazolam is optimal for any procedural sedation. Midazolam is known to cause anterograde amnesia; however, the possibility of retrograde amnesia has also been raised. This prospective cohort, nonrandomized study evaluated the presence and extent of retrograde amnesia induced by midazolam during cesarean delivery.

METHODS

One-hundred parturients scheduled for elective cesarean delivery under spinal anesthesia were enrolled. As soon as giving birth, 6 picture cards were shown to the patients in one min intervals, and then midazolam (0.1 mg/kg) was given or not according to the patients' preference. This overall retrograde recall rate of six cards was the primary outcome of our study, which was asked by a blinded investigator.

RESULTS

The overall retrograde card recall rate was lower in the midazolam group compared to the control group (77.0 ± 13.4 vs. 87.7 ± 3.9%, p <0.001), especially at one min before midazolam administration (58 vs. 88%, p <0.001). Decreased memory trend was observed as time progressed toward midazolam administration in the midazolam group (p = 0.035). More patients answered 'yes' to the factitious event in the midazolam group than in the control group (26% vs. 4%, p = 0.004).

CONCLUSION

Intravenous midazolam could cause a brief-period retrograde amnesia in visual and event memory. Moreover, there were more spurious reports of intraoperative factitious events in the midazolam group, implying that episodic memories were also affected by midazolam.

Prevalence of postoperative delirium with different combinations of intraoperative general anesthetic agents in patients undergoing cardiac surgery: A retrospective propensity-score-matched study

Postoperative delirium (PD) remains an issue in cardiac surgery despite the constant efforts to reduce its incidence. In this retrospective study, the incidence of PD was evaluated in patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) according to different primary anesthetic agents: sevoflurane and dexmedetomidine- versus propofol-based anesthesia.A total of 534 patients who underwent heart-valve surgery or coronary artery bypass graft surgery with CPB between January 2012 and August 2017 were divided into 2 groups according to the main anesthetic agent: sevoflurane with dexmedetomidine (sevo-dex group, n = 340) and propofol (propofol group, n = 194). The incidence of PD was evaluated as the primary outcome. Patient-, surgery-, and anesthesia-related factors and postoperative complications were investigated as secondary outcomes. To reduce the risk of confounding effects between the 2 groups, 194 patients were selected from the sevo-dex group after propensity-score matching.After propensity-score matching, the incidence of PD was not significantly different between the sevo-dex (6.2%) and propofol (10.8%) groups (P = .136). In comparisons of the incidence of each type of PD, only hyperactive PD occurred significantly less frequently in the sevo-dex group (P = .021). Older age, lower preoperative albumin levels, and emergency surgery were significant risk factors for PD.The overall incidence of PD after cardiac surgery with CPB did not differ between patients receiving sevoflurane and dexmedetomidine-based versus propofol-based anesthesia. Only hyperactive PD occurred less frequently in patients receiving sevoflurane and dexmedetomidine-based anesthesia.

Efficacy of Erector Spinae Plane Block for Analgesia in Thoracic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The objective of this study was to determine whether erector spinae plane block (ESPB) can provide an effective analgesia for managing pain after thoracic surgery and compare the efficacy of ESPB with that of other regional analgesic techniques.

DESIGN

Systematic review and meta-analysis of randomized controlled trials.

SETTING

PubMed, EMBASE, CENTRAL, CINAHL, Scopus, and Web of Science were searched.

PARTICIPANTS

Patients undergoing thoracic surgeries.

INTERVENTION

Erector spinae plane block with local anesthetics for postoperative analgesia.

MEASUREMENT AND MAIN RESULTS

Seventeen studies, including 1,092 patients, were included in the final analysis. Erector spinae plane block reduced 24-hour postoperative opioid consumption (mean difference [MD] -17.49, 95% CI -26.87 to -8.12), pain score at rest (MD -0.82, 95% CI -1.31 to -0.33), and pain score at movement (MD -0.77, 95% CI -1.20 to -0.3) compared to no block. Compared with other regional blocks, various results have been observed. Although statistical results showed that ESPB is inferior to thoracic paravertebral block and intercostal nerve block and superior to serratus anterior plan block in postoperative analgesia, clinical differences remain unclear. The incidence of hematoma was lower in the ESPB group than in the other groups (odds ratio 0.19, 95% CI 0.05-0.73).

CONCLUSION

Erector spinae plane block may provide effective analgesia after thoracic surgery. Compared with other techniques, it is a safer method, without clinically important differences, for postoperative pain control. Therefore, ESPB may be considered as a valuable option for postoperative pain management after thoracic surgery.

The influence of moderate or deep neuromuscular block status on anesthetic depth monitoring system during total intravenous anesthesia using propofol and remifentanil: A randomized trial

The neuromuscular block state may affect the electroencephalogram-derived index representing the anesthetic depth. We applied an Anesthetic Depth Monitoring for Sedation (ADMS) to patients undergoing laparoscopic cholecystectomy under total intravenous anesthesia, and evaluated the requirement of propofol according to the different neuromuscular block state. Adult patients scheduled to undergo laparoscopic cholecystectomy were enrolled and randomly assigned to either the moderate (MB) or deep neuromuscular block (DB) group. The UniCon sensor of ADMS was applied to monitor anesthetic depth and the unicon value was maintained between 40 and 50 during the operation. According to the group assignment, intraoperative rocuronium was administered to maintain proper neuromuscular block state, moderate or deep block state. The unicon value, electromyography (EMG) index, and total dose of propofol and rocuronium were analyzed. At similar anesthetic depth, less propofol was used in the DB group compared to the MB group (6.19 ± 1.36 in the MB mg/kg/h group vs 4.93 ± 3.02 mg/kg/h in the DM group, p = 0.042). As expected, more rocuronium were used in the DB group than in the MB group (0.8 ± 0.2 mg/kg in the MB group vs 1.2 ± 0.2 mg/kg in the DB group, p = 0.023) and the EMG indices were lower in the DB group than in the MB group, at several time points as follows: at starting operation (p < 0.001); at 15 (p = 0.019), 45 (p = 0.011), and 60 min (p < 0.001) after the initiation of the operation; at the end of operation (p = 0.003); and at 5 min after the administration of sugammadex (p < 0.001). At similar anesthetic depth, patients under the deep neuromuscular block state required less propofol with lower intraoperative EMG indices compared to those under the moderate neuromuscular block state during general anesthesia.

Role of Unfolded Protein Response and Endoplasmic Reticulum-Associated Degradation by Repeated Exposure to Inhalation Anesthetics in Caenorhabditis elegans

Background: When an imbalance occurs between the demand and capacity for protein folding, unfolded proteins accumulate in the endoplasmic reticulum (ER) lumen and activate the unfolded protein response (UPR). In addition, unfolded proteins are cleared from the ER lumen for ubiquitination and subsequent cytosolic proteasomal degradation, which is termed as the ER-associated degradation (ERAD) pathway. This study focused on changes in the UPR and ERAD pathways induced by the repeated inhalation anesthetic exposure in Caenorhabditis elegans. Methods: Depending on repeated isoflurane exposure, C. elegans was classified into the control or isoflurane group. To evaluate the expression of a specific gene, RNA was extracted from adult worms in each group and real-time polymerase chain reaction was performed. Ubiquitinated protein levels were measured using western blotting, and behavioral changes were evaluated by chemotaxis assay using various mutant strains. Results: Isoflurane upregulated the expression of ire-1 and pek-1 whereas the expression of atf-6 was unaffected. The expression of both sel-1 and sel-11 was decreased by isoflurane exposure, possibly indicating the inhibition of retro-translocation. The expression of cdc-48.1 and cdc-48.2 was decreased and higher ubiquitinated protein levels were observed in the isoflurane group than in the control, suggesting that deubiquitination and degradation of misfolded proteins were interrupted. The chemotaxis indices of ire-1, pek-1, sel-1, and sel-11 mutants decreased significantly compared to N2, and they were not suppressed further even after the repeated isoflurane exposure. Conclusion: Repeated isoflurane exposure caused significant ER stress in C. elegans. Following the increase in UPR, the ERAD pathway was disrupted by repeated isoflurane exposure and ubiquitinated proteins was accumulated subsequently. UPR and ERAD pathways are potential modifiable neuroprotection targets against anesthesia-induced neurotoxicity.

Effects of tranexamic acid on the activity of glutamate transporter EAAT3

Background

Tranexamic acid (TXA) is the most widely used hemostatic agent in surgical patients. However, when used in a high dose, it could cause a seizure in the postoperative period. The exact effector mechanism behind the seizure triggering remains unknown. Therefore, the authors investigated the effects of TXA on the activity of glutamate transporter type 3 (excitatory amino acid transporter 3; EAAT3), which is the main neuronal glutamate transporter type.

Methods

EAAT3 was expressed in Xenopus laevis oocytes through mRNA injection. Oocytes were incubated with diluted tranexamic acid for 72 h. Two-electrode voltage clamping was used to measure membrane currents before, during, and after applying 30 µM L-glutamate. Responses were quantified by integrating the current traces and reported in microcoulombs (µC). Results were presented as mean ± SEM.

Results

TXA (30 to 1,000 µM) significantly decreased EAAT3 activity. Our kinetic study showed that V_max was significantly decreased in the TXA group compared with the control group (1.1 ± 0.1 vs. 1.4 ± 0.1 µC, n = 18–23, P = 0.043), but the K_m did not significantly change (12.7 ± 3.9 µM for TXA vs. 12.8 ± 3.8 for control, n = 18–23, P = 0.986).

Conclusions

Our results suggest that TXA attenuates EAAT3 activity, which may explain its proconvulsant effect.

Retrospective Comparison between the Effects of Propofol and Inhalation Anesthetics on Postoperative Recurrence of Early- and Intermediate-Stage Hepatocellular Carcinoma

OBJECTIVE

Previous studies have reported that propofol has antitumor, anti-inflammatory, and antioxidant effects in addition to its anesthetic properties. To confirm this, a retrospective investigation was conducted to determine whether different anesthetic agents, particularly propofol and inhalation anesthetics, have an effect on the recurrence of hepatocellular carcinoma (HCC) in patients who were diagnosed with primary HCC and underwent laparoscopic hepatectomy.

SUBJECTS AND METHODS

Patients with Barcelona Clinic Liver Cancer stages 0, A, and B HCC, who underwent laparoscopic hepatic resection, were enrolled in this study. Post-operative HCC recurrence, which was determined from postoperative liver CT, was evaluated 24 months postoperatively with respect to the main anesthetic agents. The characteristics of HCC and other patient-related or surgery-related variables were evaluated together.

RESULTS AND CONCLUSION

During the 24-month period after hepatic resection, less HCC patients in the propofol group than in the inhalation group recurred (p = 0.046). The mean time to recurrence was 20.8 months (95% CI, 19.7-22.0) and 19.1 months (95% CI, 17.8-20.4) in the propofol group and the inhalation group, respectively. In addition, multivariable Cox proportional regression analysis revealed that the propofol group showed significantly decreased recurrence versus the inhalation group (hazard ratio, 0.57; 95% CI, 0.47-0.69; p = 0.029). When propofol was used as the main general anesthetic agent for laparoscopic hepatic resection, the postoperative 2-year recurrence rate decreased in early- and intermediate-stage HCC.

Association of Preoperative Serum Chloride Levels With Mortality and Morbidity After Noncardiac Surgery: A Retrospective Cohort Study

BACKGROUND

Postoperative hyperchloremia is known to be related to increases in mortality and morbidity after surgery. However, the relationship between preoperative hyperchloremia and hypochloremia and postoperative mortality and morbidity is not well established. Our aim was to evaluate the relationship between preoperative hyperchloremia or hypochloremia, as assessed using preoperative serum chloride tests, and 90-day mortality and morbidity after noncardiac surgery.

METHODS

In this retrospective cohort study, we reviewed the medical records of patients >20 years of age who underwent noncardiac surgery between January 2010 and December 2016. Patients were categorized into one of the following groups on the basis of the results of serum chloride testing performed within 1 month before surgery: normochloremia, 97-110 mmol·L; hyperchloremia, >110 mmol·L; and hypochloremia, <97 mmol·L. The primary end point of this study was the difference in postoperative 90-day mortality among the preoperative serum chloride groups. The secondary end point was the difference in postoperative acute kidney injury incidence among the preoperative serum chloride groups.

RESULTS

A total of 106,505 patients were included in the final analysis (2147 were allocated to the preoperative hypochloremia group and 617 to the hyperchloremia group). Multivariable Cox regression analysis revealed significantly increased 90-day mortality in the hypochloremia (hazard ratio, 1.46; 95% CI, 1.16-1.84; P = .001) and hyperchloremia (hazard ratio, 1.76; 95% CI, 1.13-2.73; P = .013) groups when compared with the normochloremia group. In addition, multivariable logistic regression analysis revealed a 1.83-fold increased odds of acute kidney injury in the preoperative hypochloremia group when compared with the normochloremia group (odds ratio, 1.83; 95% CI, 1.53-2.19; P < .001).

CONCLUSIONS

Preoperative hypochloremia and hyperchloremia were related to increased 90-day mortality after noncardiac surgery. In addition, preoperative hypochloremia was related to an increased risk for postoperative acute kidney injury.

Comparison of Intraoperative Sedation With Dexmedetomidine Versus Propofol on Acute Postoperative Pain in Total Knee Arthroplasty Under Spinal Anesthesia: A Randomized Trial

BACKGROUND

In patients undergoing total knee arthroplasty under spinal anesthesia, we compared the postoperative analgesic effect of intraoperative sedation with dexmedetomidine versus propofol. We hypothesized that sedation with dexmedetomidine would result in lower postoperative opioid analgesic consumption than with propofol.

METHODS

Forty-eight patients were enrolled and randomly assigned to either a dexmedetomidine group (n = 24), which received a loading dose of 1 μg/kg dexmedetomidine over 10 minutes, followed by a continuous infusion of 0.1-0.5 μg·kg·hour, or a propofol group (n = 24), which received a continuous infusion of propofol via a target-controlled infusion to maintain the effect-site concentration within a range of 0.5-2.0 μg/mL. The drug infusion rate was determined according to the sedation level, targeting a modified observer's assessment of alertness/sedation score of 3 or 4. The cumulative amounts of fentanyl administered via intravenous patient-controlled analgesia were recorded at 24 and 48 hours postoperatively (primary outcome). The postoperative numerical rating scale for pain was assessed at 6, 12, 24, and 48 hours (secondary outcome). The postoperative use of additional rescue analgesic (ketoprofen) and antiemetic drugs was also compared between the 2 groups at 24 and 48 hours.

RESULTS

Dexmedetomidine significantly reduced postoperative fentanyl consumption (median [interquartile range]) during 0-24 hours (45 [30-71] vs 150 [49-248] μg, P = .004; median difference = -105 μg [99.98% CI, 210-7.5]), 24-48 hours (90 [45-143] vs 188 [75-266] μg, P = .005; median difference = -98 μg [99.98% CI, 195-45]), and 0-48 hours (135 [68-195] vs 360 [146-480] μg, P = .003; median difference = -225 μg [99.98% CI, 405-7.5]). The numerical rating scale (median [interquartile range]) was lower at 6 hours (1 [0-2] vs 2 [1-3], P = .003), 12 hours (1 [1-2] vs 3 [2-3], P < .001), 24 hours (1 [1-2] vs 3 [2-3], P < .001), and 48 hours (2 [2-3] vs 3 [3-4], P < .001) after surgery in the dexmedetomidine group compared to the propofol group. No significant intergroup differences were observed in the amount of rescue analgesics and antiemetics at 24 hours (P = .155 and P = .482) and 48 hours (P = .082 and P = .153) after surgery.

CONCLUSIONS

Intraoperative dexmedetomidine sedation was associated with a small but clinically important reduction in postoperative opioid use after total knee arthroplasty.

Intraoperative continuous noninvasive hemoglobin monitoring in patients with placenta previa undergoing cesarean section: a prospective observational study

Background

Obstetric patients with placenta previa are at risk for sever peripartum hemorrhage. Early detection of anemia and proper transfusion strategy are important for the management of obstetric hemorrhage. In this study, we assessed the utility and accuracy of noninvasive hemoglobin (SpHb) monitoring in patients with placenta previa during cesarean section.

Methods

Parturients diagnosed with placenta previa and scheduled for cesarean section under spinal anesthesia were enrolled. SpHb and laboratory Hb (Lab-Hb) were measured during surgery as primary outcomes.

Results

Seventy-four pairs of SpHb and Lab-Hb were collected from 39 patients. The correlation coefficient was 0.877 between SpHb and Lab-Hb (P < 0.001). The Bland–Altman plot showed a mean difference ± SD of 0.3 ± 0.8 g/dl between noninvasive Hb and Lab-Hb, and the limits of agreement were −1.2 to 1.8 g/dl. The magnitude of the difference between SpHb and Lab-Hb was < 0.5 g/dl in 64.9%; however, it was > 1.5 g/dl in 10.8%.

Conclusions

SpHb monitoring had a good correlation with Lab-Hb. A small mean difference between SpHb and lab-Hb might not be clinically significant; however, the limits of agreements were not narrow. In particular, SpHb could be overestimated in the anemic population. Based on our results, further studies investigating the accuracy and precision of SpHb monitoring should be performed in parturients presenting Hb below 10 g/dl.

Comparison of standard versus 90° rotation technique for LMA Flexible™ insertion: a randomized controlled trial

Background

Insertion of a flexible laryngeal mask airway (LMA Flexible) is known to be more difficult than that of a conventional laryngeal mask airway. The 90° rotation technique can improve the success rate with a conventional laryngeal mask airway but its effect with the LMA Flexible remains unknown. We assessed whether the 90° rotation technique increased the first-attempt success rate of LMA Flexible insertion versus the standard technique.

Methods

In total, 129 female patients undergoing breast surgery were analyzed. The primary endpoint was success at the first attempt. The insertion time, number of trials, number of manipulations required, and oropharyngeal leak pressure were also evaluated. Heart rate and mean blood pressure were recorded 1 min before and 1 min after insertion. Blood staining on the LMA Flexible after removal and postoperative sore throat were checked.

Results

The first-attempt success rates were comparable between the groups (93% vs. 98.3%, P = .20). The insertion time, number of trials and manipulations, hemodynamic variables, and complications, such as blood staining and sore throat, did not differ between the groups.

Conclusions

The 90° rotation technique is a good alternative to the standard technique for insertion of the LMA Flexible.

Trial registration

ClinicalTrials.gov (NCT03028896). It was registered retrospectively at Jan 19th, 2017.

The effect of neuromuscular reversal agent on postoperative pain after laparoscopic gastric cancer surgery: Comparison between the neostigmine and sugammadex

Use of sugammadex for neuromuscular block reversal is associated with fewer postoperative complications than neostigmine; however, the effects on postoperative pain outcomes are largely unknown. In this retrospective study, we investigated the relationship between neuromuscular reversal agents and postoperative pain-related outcomes following laparoscopic gastric cancer surgery.We reviewed the electronic health records of patients who underwent laparoscopic gastric cancer surgery between January 2010 and June 2017. Patients were divided into a sugammadex group and a neostigmine group, according to the neuromuscular block reversal agent used. We compared the pain outcomes in the first 3 days postoperatively (POD 0-3), length of hospital stay, and postoperative complications (Clavien-Dindo grade ≥II).During the study period, 3056 patients received sugammadex (n = 901) or neostigmine (n = 2155) for neuromuscular reversal. After propensity score matching, 1478 patients (739 in each group) were included in regression analysis. In linear regression analysis, intravenous morphine equivalent consumption (mg) during POD 0 to 3 was higher in the sugammadex group than in the neostigmine group [coefficient 103.41, 95% confidence interval (CI): 77.45-129.37; P <.001]. However, hospital stay was shorter (coefficient: -0.60, 95% CI -1.12 to -0.08; P = .025) and postoperative complication rate was lower (odds ratio: 0.20, 95% CI 0.07-0.58; P = .003) in the sugammadex group.In this retrospective study, patients undergoing laparoscopic gastric cancer surgery who received sugammadex for neuromuscular block reversal exhibited greater postoperative analgesic requirements than those who received neostigmine but had a shorter hospital stay and a lower postoperative complication rate. A randomized and blinded study should be conducted in the future to confirm the findings of the present study.

Perioperative sedative use is not associated with acute kidney injury after total hip or knee arthroplasty

Background

The use of sedatives (propofol or dexmedetomidine) is common in total knee arthroplasty (TKA) or total hip arthroplasty (THA) under spinal anesthesia. Although propofol and dexmedetomidine have been reported to decrease the risk of acute kidney injury (AKI) after cardiac surgery, their effects on AKI incidence after TKA or THA are still unknown. The purpose of this study was to investigate the associations between sedative dosage (propofol and dexmedetomidine) and AKI incidence after TKA or THA under spinal anesthesia.

Methods

This retrospective observational study analyzed medical records of adult patients aged 18 years or older who underwent unilateral TKA or THA under spinal anesthesia at a single tertiary care hospital between January 2007 and June 2018. Data were analyzed using univariable and multivariable logistic regression analyses.

Results

A total of 5,663 patients were included in the analysis (TKA: 3,570, 63.0%; THA: 2,093, 37.0%), and 147 patients (2.6%) developed AKI in postoperative days 0-3. Multivariable logistic regression analysis showed that propofol dosage (odds ratio: 0.99, 95% confidence interval: 0.94, 1.05; P=0.839) and dexmedetomidine dosage (odds ratio: 0.95, 95% confidence interval: 0.84, 1.09; P=0.461) were not significantly associated with AKI incidence.

Conclusions

This study demonstrated no significant association between sedative uses (propofol, dexmedetomidine) and AKI incidence after THA or TKA under spinal anesthesia, and use of such sedatives does not require extreme caution.

A Comparison of Hemostatic Properties between Monopolar and Bipolar Hysteroscopic Surgery using Rotational Thromboelastometry: A Randomized Trial

OBJECTIVE

Systemic absorption of irrigation fluid can lead to a disturbed coagulation cascade. We compared the changes in hemostatic properties on using nonelectrolyte solution in monopolar hysteroscopic surgery (HS) with that on using isotonic saline in bipolar HS via rotational thromboelastometry (ROTEM) analysis.

METHODS

A total of 54 patients were randomized into 2 groups: 1 group underwent monopolar HS using a mixture of 2.7% sorbitol and 0.54% mannitol (the HSMP group), whereas the other group underwent bipolar HS using 0.9% isotonic saline (the HSBP group). The effects of these 2 methods on coagulation were assessed via pre and postoperative laboratory tests, including estimation of the international normalized ratio of prothrombin time and activated partial thromboplastin time and ROTEM analysis. In addition, the hemoglobin, hematocrit, and electrolyte levels and the platelet count were analyzed.

RESULTS

Patient characteristics, volume of irrigation fluid absorbed, and type of procedure were comparable between the 2 groups. There were no significant differences in the pre and postoperative values of ROTEM parameters between the 2 groups. Most postoperative ROTEM parameters, as compared with preoperative values, changed in both groups; clot formation time was prolonged, and the α-angle and maximum clot firmness were decreased. All ROTEM parameters were maintained within the normal range. Hematological parameters, including hemoglobin and hematocrit levels and platelet count, were significantly decreased postoperatively in both groups compared to the preoperative values. No pre and postoperative hematological and hemostatic parameters were significantly different between the 2 groups.

CONCLUSION

Irrigation fluid absorbed in healthy women during HS caused hypocoagulable changes in the blood, irrespective of the irrigant type, and no significant differences between HS using monopolar and bipolar electrodes were demonstrated.

The effect of repeated isoflurane exposure on serine synthesis pathway during the developmental period in Caenorhabditis elegans

BACKGROUND

Serine synthetic pathway plays an essential role in the development and function of the nervous system. This study investigated whether the serine synthetic pathway was affected by repeated volatile anesthetic exposure using C. elegans and its relationship with anesthesia-induced neurotoxicity.

METHODS

Synchronized worms were divided into two groups: the control and isoflurane groups. Worms in the isoflurane group were exposed to isoflurane for 1 h at each larval stage. The chemotaxis index was evaluated when they reached the young adult-stage in both groups. Also, RNA was extracted from the young adult-worms, and the expressions of C31C9.2, F26H9.5, and Y62E10 A.13 were evaluated using real-time polymerase chain reaction in both groups. At the same time, the l-serine level was measured. After phosphoserine phosphatase inhibitor - glycerophosphorylcholine (GPC) - and l-serine were treated, the change of chemotaxis index was determined.

RESULTS

In young adult worms exposed to isoflurane, the genetic expressions of C31C9.2, F26H9.5, and Y62E10 A.13 were decreased, and a significant decrease was shown in Y62E10 A.13. The serine level in worms was also lower in the isoflurane group than in the control group (5.13 ± 1.44 vs. 7.65 ± 0.81 pM, n = 5 in each group, p = 0.009). Exposure to GPC reduced the chemotaxis index to a similar degree as repeated isoflurane exposure (52.9% in GPC group vs 58.7% in the isoflurane group). The chemotaxis index (61.1%) was not decreased by repeated isoflurane anesthesia in GPC-treated worms. In this condition, the l-serine level was low similarly in both groups (5.22 ± 1.19 vs. 4.90 ± 1.36 pM, n = 5 in each group, p = 0.702). When l-serine was supplied to C. elegans, the deteriorated chemotaxis index by isoflurane exposure recovered (78.1% in the control group vs. 75.5% in the isoflurane group, p = 0.465).

CONCLUSION

Serine synthetic pathway was negatively affected in C. elegans by repeated isoflurane exposure. Y62E10 A.13, which corresponds to phosphoserine phosphatase, was mostly influenced, followed by low l-serine level. Supplementation with l-serine could restore the chemotaxis index.

Value of preoperative spirometry test in predicting postoperative pulmonary complications in high-risk patients after laparoscopic abdominal surgery

Whether preoperative spirometry in non-thoracic surgery can predict postoperative pulmonary complications (PPCs) is controversial. We investigated whether preoperative spirometry results can predict the occurrence of PPCs in patients who had undergone laparoscopic abdominal surgery. This retrospective observational study analyzed the records of patients who underwent inpatient laparoscopic gastric or colorectal cancer surgery at Seoul National University Bundang Hospital between January 2010 and June 2017. Preoperative spirometry was performed for patients at a high risk of PPCs, such as elderly patients (age >60 years), patients aged <60 years with chronic pulmonary disease, and current smokers. The main outcome was the association between the results of spirometry tests performed within 1 month prior to surgery and the occurrence of PPCs, as determined by multivariable logistic regression analysis. Of the 898 included patients who underwent laparoscopic gastric (372 patients) or colorectal cancer surgery (526 patients), PPC occurred in 117 patients (gastric cancer: 74, colorectal cancer: 43). A 1% greater preoperative forced vital capacity (FVC) was associated with a 2% lower incidence of PPCs after laparoscopic gastric or colorectal cancer surgery (odds ratio: 0.98, 95% confidence interval: 0.97–0.99, P = 0.018). However, the preoperative forced expiratory volume in 1 second (FEV1) (%) and FEV1/FVC (%) were not significantly associated with PPCs (P = 0.059 and P = 0.147, respectively). In conclusion, lower preoperative spirometry FVC, but not FEV1 or FEV1/FVC, may predict PPCs in high-risk patients undergoing laparoscopic abdominal surgery.

The effect of a mixture of 2.7% sorbitol-0.54% mannitol solution on blood coagulation: an invitro, observational healthyvolunteer study using rotational thromboelastometry (ROTEM)

Background

We investigated the effect of irrigation fluid on coagulation according to the hemodilution level using rotational thromboelastometry (ROTEM).

Methods

Venous blood was taken from 12 healthy volunteers and divided into four specimen tubes that were diluted to various levels (0%, 10%, 20%, and 40%) using an irrigation fluid composed of 2.7% sorbitol and 0.54% mannitol.

Results

Significant prolongation of clotting time was observed in the 40% diluted sample using both INTEM (P = 0.009) and EXTEM (P = 0.001) assays. However, the clot formation time was prolonged significantly in the 10%, 20%, and 40% diluted samples using both INTEM (P < 0.001) and EXTEM (P = 0.002, P < 0.001, and P < 0.001, respectively) assays. A significant decrease of α-angle of INTEM and EXTEM were observed in the 10% (P < 0.001), 20% (P < 0.001 and P = 0.001, respectively), and 40% (P < 0.001) groups compared with the 0% dilution group. The maximum clot firmness (MCF) of INTEM decreased significantly in the 20% (P < 0.001) and 40% (P < 0.001) diluted samples. In the MCF of EXTEM and FIBTEM assays, 10% (P = 0.009 and P = 0.015, respectively), 20% (P = 0.001), and 40% (P < 0.001) samples showed a significant decrease compared with the 0% sample. Nevertheless, most of the ROTEM values were within the reference range, except the 40% sample.

Conclusions

Blood became hypocoagulable when it was diluted in vitro with a fluid composed of 2.7% sorbitol and 0.54% mannitol.

Comparison of upper airway patency in patients with mild obstructive sleep apnea during dexmedetomidine or propofol sedation: a prospective, randomized, controlled trial

Background

In addition to propofol, dexmedetomidine is a suitable alternative for intraoperative sedation in procedures requiring regional anesthesia. To date, however, little is known about the influences of each drug on upper airway patency. Accordingly, the authors investigated differences between dexmedetomidine and propofol sedation in the occurrence of upper airway obstruction and requirements for airway intervention in patients with mild obstructive sleep apnea.

Methods

Patients with an apnea/hypopnea index of 5–14/h according to Watch-PAT 200 analysis were enrolled in this study. Spinal anesthesia was routinely performed for surgery. Intraoperative sedation was initiated using either dexmedetomidine or propofol infusion at a level of modified observer’s assessment of alertness/sedation scale 3. The primary outcome was the proportion of patients exhibiting signs of upper airway obstruction. A sign of upper airway obstruction was defined as no detection of end-tidal carbon dioxide for at least 10 s despite respiratory efforts.

Results

A total of 50 patients were included in the final analysis (dexmedetomidine [n = 26]; propofol [n = 24]). During the intraoperative sedation period, there was a significantly lower proportion of patients exhibiting signs of upper airway obstruction in the dexmedetomidine group than in the propofol group (11.5% vs. 41.7%, P = 0.035). An artificial airway was inserted in 1 patients (3.8%) and 5 patient (20.8%) in the dexmedetomidine and propofol groups, respectively (P = 0.093).

Conclusion

Dexmedetomidine sedation was associated with a lower incidence of upper airway obstruction than propofol sedation in patients with mild obstructive sleep apnea.

Trial registration number

Clinical trials.gov (NCT02993718): Retrospectively registered.

FIBTEM as a predictor of intra- and postoperative blood loss in revision total hip arthroplasty: A prospective observational study

Revision total hip arthroplasty (THA) may cause intra- and postoperative massive bleeding. This prospective observational study evaluated if the maximum clot firmness of FIBTEM (MCFFIB) could act as a predictor of perioperative massive bleeding in revision THA.Fifty-eight adult patients undergoing revision THA were included. Pre- and postoperative MCFFIB, hematological and hemostatic laboratory data, as well as the amount of intra- and postoperative blood loss (IBL and PBL) were obtained.The change rate (MCFFIB-C) between the pre- and postoperative MCFFIB had a significant correlation with IBL (ρ = 0.431, P = .001). Moreover, PBL had a significant correlation with MCFFIB-C (ρ = 0.292, P = .026). The MCFFIB-C cut-off value of ≥ 29% showed the highest sensitivity and specificity for predicting IBL ≥ 1000 mL or PBL ≥500 mL. The incidence of red blood cell transfusion in the postoperative period was higher in patients showing MCFFIB-C ≥ 29% (34% vs 8%, P = .015).The change rate between pre- and postoperative MCFFIB values was correlated well with the amount of IBL or PBL. Moreover, particular change rate of MCFFIB could predict massive bleeding in revision THA.

Intraoperative Nefopam Reduces Acute Postoperative Pain after Laparoscopic Gastrectomy: a Prospective, Randomized Study

BACKGROUND

We assessed whether intraoperative nefopam would reduce opioid consumption and relieve postoperative pain in patients undergoing laparoscopic gastrectomy.

METHODS

The 60 enrolled patients were randomly assigned to the control (n = 32) or nefopam (n = 28) group. All patients were blinded to their group assignment. We administered 100 ml of normal saline only (control group) or 20 mg of nefopam mixed in 100 ml normal saline (nefopam group) after anesthesia induction and at the end of surgery. The cumulative amount of fentanyl via intravenous patient-controlled analgesia (PCA), incidence of rescue analgesic medication, and numerical rating scale (NRS) for postoperative pain were evaluated along with the total remifentanil consumption.

RESULTS

The mean infusion rate of remifentanil was significantly lower in the nefopam group (0.08 ± 0.05 μg/kg/min) than in the control group (0.13 ± 0.06 μg/kg/min) (P < 0.001). Patients in the nefopam group required less fentanyl via intravenous PCA than those in the control group during the first 6 h after surgery (323.8 ± 119.3 μg vs. 421.2 ± 151.6 μg, P = 0.009). Additionally, fewer patients in the nefopam group than in the control group received a rescue analgesic during the initial 6 h postoperatively (78.6 vs. 96.9%, P = 0.028). The NRS measured while patients were in the post-anesthetic care unit was significantly lower in the nefopam group than in the control group (3.8 ± 1.1 vs. 4.8 ± 1.4, P = 0.012). The subsequent NRS obtained after patients had been transferred to the general ward was comparable between the two groups during the following postoperative period.

CONCLUSIONS

Intraoperative nefopam decreased postoperative pain and opioid consumption in the acute postoperative period after laparoscopic gastrectomy. Hence, nefopam may be considered as a component of multimodal analgesia after laparoscopic gastrectomy.

Comparison of intraoperative basal fluid requirements in distal pancreatectomy: Laparotomy vs. laparoscopy: A retrospective cohort study

There has been recent progress in intraoperative fluid therapy. However, little is known about intraoperative fluid therapy in laparoscopic surgery. The purpose of this study is to determine whether there are differences in the basal fluid requirements during surgery between laparotomy and laparoscopic distal pancreatectomy.This retrospective cohort study analyzed the electronic medical records of 253 patients who underwent distal pancreatectomy via either laparotomy (73 patients) or laparoscopy (180 patients) between June 2006 and March 2016. The volume of intraoperative fluid administered, postoperative complications, length of hospital stay, and readmission rate were evaluated. The total volume of fluids was calculated as the sum of the volume of crystalloid plus the volume of colloid multiplied by 1.5 or 2.0.Patients who had laparotomy were older and had higher American Society of Anesthesiologists classes. Anesthesia time was longer and estimated blood loss was larger in laparotomy. More colloid (1.8 mL/kg per h vs. 1.2 mL/kg per h, P < .001) and more total calculated fluid (1.5 times: 11.7 mL/kg per h vs. 10.6 mL/kg per h, P = .002; 2.0 times: 12.6 mL/kg per h vs. 11.2 mL/kg per h, P = .001) were infused in laparotomy. Crystalloid (9.0 mL/kg per h vs. 8.9 mL/kg per h, P = .203) did not show significant difference. Postoperative complications were more frequent (63% vs. 45%, P = .008), the hospital stay was longer (18 days vs. 13.4 days, P < .001), and readmission rate was higher (15% vs. 5.6%, P = .02) in laparotomy. By logistic regression analysis, we could find that operation type (laparotomy vs. laparoscopy, odds ratio 1.900, 95% confidence interval 1.072-3.368) and operation time (P = .004) had effect on complications.In patients undergoing distal pancreatectomy, basal fluid requirements were larger in laparotomy compared with laparoscopy. Operation time and estimated blood loss had effects on fluid administration. Postoperative complications were more frequent in laparotomy but we could not find relationships with infused colloid or total calculated fluid volumes. Operation type (laparotomy vs. laparoscopy) and operation time were the only related factors to postoperative complications.

Is neuromuscular blocker needed in children undergoing inguinal herniorrhaphy?: A prospective, randomized, and controlled trial

BACKGROUND

Intraoperative neuromuscular blocker is widely used, but is known to be associated with postoperative residual paralysis, which is known to be associated with increased risk of pulmonary complications. Hence, its use should be individualized and restricted to procedures where it is mandatory. We examined whether not using a neuromuscular blocker affects the surgical conditions in children undergoing inguinal herniorrhaphy.

METHODS

Anesthesia was induced and maintained with sevoflurane in 60% nitrous oxide, and the airway was maintained using an I-gel. In total, 66 children aged 1 to 6 years were randomized to receive rocuronium (rocuronium group, n = 33) or saline (control group, n = 33); 61 children of them finished the study. A single surgeon who performed the operation rated the surgical condition of each patient on a 4-point scale (1 = poor, 2 = acceptable, 3 = good, and 4 = excellent). Intraoperative patient movement, recovery time, emergence agitation, and postoperative pain scores were evaluated.

RESULTS

One patient in control group and no patient in rocuronium group showed intraoperative movement. When noninferiority test was done for intraoperative patient movement, with the noninferiority margin of 20%, the difference of absolute risk was 3.3% (95% confidence interval -8.0% to 16.7%) and saline group was noninferior to rocuronium group. All of the patients showed good to excellent surgical conditions, and no difference was found between the 2 groups. The recovery time was shorter in the control group than in the rocuronium group (4.5 ± 1.8 vs 5.6 ± 2.2 minutes, respectively; P = .028).

CONCLUSION

In children aged 1 to 6 years undergoing inguinal herniorhaphy under sevoflurane anesthesia using an I-gel, not using neuromuscular blocker showed similar intraoperative condition and shortened recovery time compared with using neuromouscular blocker.

Intraoperative dexmedetomidine sedation reduces the postoperative agitated behavior in elderly patients undergoing orthopedic surgery compared to the propofol sedation

BACKGROUND

Postoperative agitation or confusion is one of the symptoms of hyperactive delirium in elderly patients. We retrospectively evaluated the incidence of postoperative abnormal psychomotor behavior in elderly surgical patients according to the use of different intraoperative sedative agents: dexmedetomidine vs. propofol.

METHODS

The medical records of 855 elderly patients, who underwent orthopedic surgery with regional anesthesia between July 2012 and September 2015, were divided into two groups, the dexmedetomidine group (N.=263) and the propofol group (N.=592), and then evaluated. Agitated behavior was evaluated as the primary outcome, and patient-, surgery-, and anesthesia-related factors, as well as other postoperative complications, were investigated as secondary outcomes. To reduce the risk of confounder effects between the two groups, 263 patients were selected from the propofol group by propensity score matching.

RESULTS

In the propensity-score-matched groups, the incidence of agitated behavior was lower in the dexmedetomidine group compared with the propofol group (6 [2.3%] vs. 17 [6.5%], P=0.027). All pre- and postoperative laboratory values were comparable between the two groups, including hemoglobin, hematocrit, platelet count, C-reactive protein, electrolytes, creatinine, glomerular filtration rate, and albumin. Moreover, intraoperative propofol sedation, older age, higher Charlson comorbidity index, and hip surgery were found to be significant factors for the occurrence of agitation.

CONCLUSIONS

This study suggests that intraoperative dexmedetomidine sedation, as compared with propofol sedation, may have a greater beneficial effect in reducing agitated behavior in elderly patients undergoing orthopedic surgery with regional anesthesia.

A Study on CYP2C19 and CYP2D6 Polymorphic Effects on Pharmacokinetics and Pharmacodynamics of Amitriptyline in Healthy Koreans

We performed a double-blinded, genotype-based stratification study to explore the pharmacokinetics and pharmacodynamics of amitriptyline according to CYP2C19 and CYP2D6 genotype in Korean subjects. Twenty-four healthy adults were grouped by genotype of CYP2C19 and CYP2D6. After a single dose of 25 mg of amitriptyline, blood samples were collected and anticholinergic effects were measured. The extent of N-demethylation of amitriptyline significantly decreased in subjects carrying two nonfunctional alleles of CYP2C19. The extent of hydroxylation of amitriptyline or nortriptyline was significantly reduced in subjects carrying two CYP2D6 decreased functional alleles compared with those with no or one decreased functional allele. The overall metabolic pathway of amitriptyline was more likely to be dominated by CYP2C19 than CYP2D6. The gene variations of CYP2C19 and CYP2D6 did not change the pharmacodynamic effect. The findings of this study will provide useful information on individualized drug treatment with amitriptyline considering both CYP2D6 and CYP2C19 gene variations.

The impact of irrigating fluid absorption on blood coagulation in patients undergoing transurethral resection of the prostate: A prospective observational study using rotational thromboelastometry

Although endoscopic transurethral resection of the prostate (TURP) is a well-established procedure as a treatment for benign prostatic hyperplasia, its complications remain a concern. Among these, coagulopathy may be caused by the absorption of irrigating fluid. This study aimed to evaluate such phenomenon using a rotational thromboelastometry (ROTEM).A total of 20 patients undergoing TURP participated in this study. A mixture of 2.7% sorbitol-0.54% mannitol solution and 1% ethanol was used as an irrigating fluid, and fluid absorption was measured via the ethanol concentration in expired breath. The effects on coagulation were assessed by pre- and postoperative laboratory blood tests, including hemoglobin, hematocrit, platelet count, international normalized ratio of prothrombin time (PT-INR), activated partial thromboplastin time, electrolyte, and ROTEM.INTEM-clotting time (INTEM-CT) was significantly lengthened by 14% (P = 0.001). INTEM-α-angle was significantly decreased by 3% (P = 0.011). EXTEM-clot formation time was significantly prolonged by 18% (P = 0.008), and EXTEM-maximum clot firmness (EXTEM-MCF) was significantly decreased by 4% (P = 0.010). FIBTEM-MCF was also significantly decreased by 13% (P = 0.015). Moreover, hemoglobin (P < 0.001), hematocrit (P < 0.001), platelet counts (P < 0.001), potassium (P = 0.024), and ionized calcium (P = 0.004) were significantly decreased, while PT-INR (P = 0.001) was significantly increased after surgery. The amount of irrigating fluid absorbed was significantly associated with the weight of resected prostatic tissue (P = 0.001) and change of INTEM-CT (P < 0.001).As shown by the ROTEM analysis, the irrigating fluid absorbed during TURP impaired the blood coagulation cascade by creating a disruption in the coagulation factor activity or by lowering the coagulation factor concentration via dilution.

A prospective, randomized and controlled study of interscalene brachial plexus block for arthroscopic shoulder surgery: A comparison of C5 and conventional approach, a CONSORT-compliant article

BACKGROUND

The shoulder area is mainly innervated with the C5 and C6 nerve roots, and interscalene brachial plexus block (ISB) is widely used for postoperative analgesia after shoulder surgery. However, it is associated with adverse effects, such as numbness and weakness in the blocked arm due to an unwanted block of the lower brachial plexus (C7-T1). We hypothesized that the C5 approach during ISB would provide postoperative analgesia while minimizing adverse events after arthroscopic shoulder surgery.

METHODS

A total of 92 patients scheduled for arthroscopic shoulder surgery were enrolled and randomly assigned to 1 of the 3 groups: The control (no ISB, n = 31), conventional ISB (ISB with the conventional approach, n = 31), or C5 ISB (ISB with the C5 approach, n = 30) group. ISB was performed before the induction of anesthesia, and a subacromial catheter was placed in all patients at the end of the surgery. Postoperative pain scores, numbness, and weakness were recorded at 2, 8, and 24 hours after surgery. Oxygen saturation and overall patient satisfaction scores were also assessed at 1 and 48 hour after surgery, respectively.

RESULTS

The pain scores were lower in the conventional ISB group and the C5 ISB group than in the control group at postoperative 2 and 8 hours (P < 0.05). The incidence and degree of numbness and weakness of the blocked arm were significantly lower in the C5 ISB group than in the conventional ISB group (P < 0.05). Oxygen saturation were lower in the conventional ISB group and C5 ISB group than in the control group (P = 0.01). Overall patient satisfaction scores were higher in the C5 ISB group than in the control or conventional ISB group (P < 0.01).

CONCLUSION

The C5 approach for ISB provides analgesia as effectively as the conventional approach following arthroscopic shoulder surgery, with the advantages of minimal numbness and weakness.

The effect of hyperglycemia on blood coagulation: In vitro, observational healthy-volunteer study using rotational thromboelastometry (ROTEM)

We performed a study to investigate whether contamination of hemostasis samples with a glucose-containing solution might generate spurious results in rotational thromboelastometry (ROTEM) tests.Venous blood was taken from 12 healthy volunteers and divided into 4 specimen bottles, which were contaminated with different concentrations (0%, 5%, 10%, and 20%) of glucose solution.Significant lengthening of INTEMCT was observed in the 10% and 20% groups compared with baseline values (7.7% and 9%, P = 0.041 and P = 0.037, respectively). INTEMCFT increased by 20.1% in the 20% group (P = 0.005). INTEMα-angle and INTEMMCF decreased by 3.9% and 2.7%, respectively, in the 20% group (P = 0.010 and P = 0.049, respectively). EXTEMCFT was prolonged significantly, by 10.2%, 15.5%, and 25.6%, in the 5%, 10%, and 20% groups, respectively (P = 0.004, P < 0.001, and P < 0.001, respectively). EXTEMα-angle decreased significantly by 1.9%, 3.2%, and 4.0% in the 5%, 10%, and 20% groups, respectively (P = 0.014, P = 0.001, and P = 0.005, respectively). EXTEMMCF decreased by 3.4% in the 20% group (P = 0.023). FIBTEMMCF decreased by 9.2% and 17.5% in the 10% and 20% groups, respectively (P = 0.019 and P = 0.021, respectively). A significant correlation was observed between standard glucose solution contamination in the specimens and percentage variation of EXTEMCFT, EXTEMMCF, and FIBTEMMCF.To obtain accurate data from the ROTEM test regarding the hemostatic status of patients, specimens with suspected or known contamination should not be analyzed.