Perioperative Supplemental Oxygen and Postoperative Nausea and Vomiting: Subanalysis of a Trial, Systematic Review, and Meta-analysis.

BACKGROUND: Intraoperative supplemental oxygen may reduce postoperative nausea and vomiting by mitigating hypoxic stress on the gastrointestinal tract. The authors therefore tested the hypothesis that supplemental oxygen reduces nausea and vomiting in adults recovering from colorectal surgery at the Cleveland Clinic between January 28, 2013, and March 11, 2016. METHODS: Initially, the authors conducted an unplanned subanalysis of a previous trial that evaluated the effect of 80% versus 30% intraoperative inspired oxygen on surgical site infection. Specifically, they assessed the effect of 80% versus 30% oxygen concentration on the incidence of postoperative nausea and/or vomiting. Thereafter, the authors conducted a systematic review and meta-analysis of the effect of supplemental oxygen on postoperative nausea and vomiting. RESULTS: The authors' underlying analysis included 5,057 colorectal surgeries on 4,001 patients. For 2,554 surgeries, assignment was to 80% oxygen, and in 2,503 surgeries, to 30%. Postoperative nausea and vomiting was 852 of 2,554 (33%) in 80% oxygen and 814 of 2,503 (33%) in 30% oxygen. The estimated relative risk (95% CI) of 80% versus 30% oxygen on postoperative nausea and vomiting was 1.04 (0.96 to 1.12) in a generalized estimating equation model adjusting for within-patient correlation for patients with multiple surgeries, P = 0.355. Furthermore, supplemental oxygen did not reduce antiemetic use (P = 0.911) or the severity of nausea and vomiting (P = 0.924). The authors' meta-analysis included 10 qualifying trials (6,749 patients) and did not find a difference in postoperative nausea and vomiting: relative risk, 0.97 [95% CI, 0.86 to 1.08], P = 0.55, I2 = 52%. CONCLUSIONS: The incidence of postoperative nausea and vomiting did not differ in patients assigned to 80% or 30% inspired oxygen. A meta-analysis of available trials similarly indicated that supplemental intraoperative oxygen does not reduce postoperative nausea and vomiting. Therefore, supplemental oxygen should not be given in the expectation that it will reduce nausea and vomiting.

Nociception Level Index-Guided Intraoperative Analgesia for Improved Postoperative Recovery: A Randomized Trial.

BACKGROUND: Nociception is the physiological response to nociceptive stimuli, normally experienced as pain. During general anesthesia, patients experience and respond to nociceptive stimuli by increasing blood pressure and heart rate if not controlled by preemptive analgesia. The PMD-200 system from Medasense (Ramat Gan, Israel) evaluates the balance between nociceptive stimuli and analgesia during general anesthesia and generates the nociception level (NOL) index from a single finger probe. NOL is a unitless index ranging from 0 to 100, with values exceeding 25 indicating that nociception exceeds analgesia. We aimed to demonstrate that titrating intraoperative opioid administration to keep NOL <25 optimizes intraoperative opioid dosing. Specifically, we tested the hypothesis that pain scores during the initial 60 minutes of recovery are lower in patients managed with NOL-guided fentanyl than in patients given fentanyl per clinical routine. METHODS: We conducted a randomized, single-center trial of patients having major abdominal open and laparoscopic surgeries. Patients were randomly assigned 1:1 to intraoperative NOL-guided fentanyl administration or fentanyl given per clinical routine. The primary outcome was pain score (0-10 verbal response scale) at 10-minute intervals during the initial 60 minutes of recovery. Our secondary outcome was a measure of adequate analgesia, defined as a pain score <5, assessed separately at each interval. RESULTS: With a planned maximum sample size of 144, the study was stopped for futility after enrolling 72 patients from November 2020 to October 2021. Thirty-five patients were assigned to NOL-guided analgesic dosing and 37 to routine care. Patients in the NOL group spent significantly less time with a NOL index >25 (median reduction [95% confidence interval {CI}] of 14 [4-25] minutes) were given nearly twice as much intraoperative fentanyl (median [quartiles] 500 [330, 780] vs 300 [200, 330] µg), and required about half as much morphine in the recovery period (3.3 [0, 8] vs 7.7 [0, 13] mg). However, in the primary outcome analysis, NOL did not reduce pain scores in the first 60 minutes after awakening, assessed in a linear mixed effects model with mean (standard error [SE]) of 4.12 (0.59) for NOL and 4.04 (0.58) for routine care, and estimated difference in means of 0.08 (-1.43, 1.58), P = .895. CONCLUSIONS: More intraoperative fentanyl was given in NOL-guided patients, but NOL guidance did not reduce initial postoperative pain scores.

Prolonged Blood Storage and Risk of Posttransfusion Acute Kidney Injury.

BACKGROUND: Erythrocyte transfusions are independently associated with acute kidney injury. Kidney injury may be consequent to the progressive hematologic changes that develop during storage. This study therefore tested the hypothesis that prolonged erythrocyte storage increases posttransfusion acute kidney injury. METHODS: The Informing Fresh versus Old Red Cell Management (INFORM) trial randomized 31,497 patients to receive either the freshest or oldest available matching erythrocyte units and showed comparable mortality with both. This a priori substudy compared the incidence of posttransfusion acute kidney injury in the randomized groups. Acute kidney injury was defined by the creatinine component of the Kidney Disease: Improving Global Outcomes criteria. RESULTS: The 14,461 patients included in this substudy received 40,077 erythrocyte units. For patients who received more than one unit, the mean age of the blood units was used as the exposure. The median of the mean age of blood units transfused per patient was 11 days [interquartile range, 8, 15] in the freshest available blood group and 23 days [interquartile range, 17, 30] in the oldest available blood group. In the primary analysis, posttransfusion acute kidney injury was observed in 688 of 4,777 (14.4%) patients given the freshest available blood and 1,487 of 9,684 (15.4%) patients given the oldest available blood, with an estimated relative risk (95% CI) of 0.94 (0.86 to 1.02; P = 0.132). The secondary analysis treated blood age as a continuous variable (defined as duration of storage in days), with an estimated relative risk (95% CI) of 1.00 (0.96 to 1.04; P = 0.978) for a 10-day increase in the mean age of erythrocyte units. CONCLUSIONS: In a population of patients without severely impaired baseline renal function receiving fewer than 10 erythrocyte units, duration of blood storage had no effect on the incidence of posttransfusion acute kidney injury.

Effect of Intravenous Acetaminophen on Mean Arterial Blood Pressure: A Post Hoc Analysis of the EFfect of Intravenous ACetaminophen on PosToperative HypOxemia After Abdominal SurgeRy Trial.

BACKGROUND: Acetaminophen is commonly used as part of multimodal analgesia for acute pain. The intravenous formulation offers a more predictable bioavailability compared to oral and rectal acetaminophen. There have been reports of hypotension with intravenous acetaminophen attributable to centrally mediated and vasodilatory effects. We tested the hypothesis that in adults having abdominal surgery the use of intravenous acetaminophen versus placebo for postoperative pain management is associated with a decrease in mean arterial pressure (MAP) after its administration. METHODS: This is a substudy of eFfect of intravenous ACetaminophen on posToperative hypOxemia after abdominal surgeRy (FACTOR) trial (NCT02156154). FACTOR trial randomly assigned adults undergoing abdominal surgery to either 1 g of acetaminophen or placebo every 6 hours during the first postoperative 48 hours. Continuous monitoring of blood pressure was obtained by noninvasive ViSi Mobile device (Sotera Wireless, Inc, San Diego, CA) at 15-second intervals during initial 48 hours postoperatively. We excluded patients without continuous monitoring data available. The primary outcome was the MAP difference between MAP 5 minutes before study drug administration (baseline) and MAP 30 minutes poststudy drug administration initiation. We used a linear mixed effects model to assess the treatment effect on MAP change. The secondary outcome was MAP area under baseline (AUB) during the 30 minutes after treatment. In a sensitivity analysis of change in MAP from predrug to postdrug administration, we instead used postdrug MAP as the outcome adjusting for the baseline MAP in the model. RESULTS: Among 358 patients analyzed, 182 received acetaminophen and 176 placebo. The mean (standard deviation [SD]) of average MAP change was -0.75 (5.9) mm Hg for the treatment and 0.32 (6.3) mm Hg for the placebo. Acetaminophen was found to decrease the MAP from baseline more than placebo after drug administration. The estimated difference in mean change of MAP was -1.03 (95% confidence interval [CI] -1.60 to -0.47) mm Hg; P < .001. The sensitivity analysis showed postoperative MAP in the acetaminophen group was 1.33 (95% CI, 0.76-1.90) mm Hg lower than in the placebo group (P < .001). The median of MAP AUB was 33 [Q1 = 3.3, Q3 = 109] mm Hg × minutes for the treatment and 23 [1.6, 79] mm Hg × minutes for the placebo. Acetaminophen was found to increase the AUB with an estimated median difference of 15 (95% CI, 5-25) mm Hg × minutes (P = .003). CONCLUSIONS: Intravenous acetaminophen decreases MAP after its administration. However, this decrease does not appear to be clinically meaningful. Clinicians should not refrain to use intravenous acetaminophen for acute pain management because of worries of hypotension.

Saline versus Lactated Ringer's Solution: The Saline or Lactated Ringer's (SOLAR) Trial.

BACKGROUND: Both saline and lactated Ringer's solutions are commonly given to surgical patients. However, hyperchloremic acidosis consequent to saline administration may provoke complications. The authors therefore tested the primary hypothesis that a composite of in-hospital mortality and major postoperative complications is less common in patients given lactated Ringer's solution than normal saline. METHODS: The authors conducted an alternating cohort controlled trial in which adults having colorectal and orthopedic surgery were given either lactated Ringer's solution or normal saline in 2-week blocks between September 2015 and August 2018. The primary outcome was a composite of in-hospital mortality and major postoperative renal, respiratory, infectious, and hemorrhagic complications. The secondary outcome was postoperative acute kidney injury. RESULTS: Among 8,616 qualifying patients, 4,187 (49%) were assigned to lactated Ringer's solution, and 4,429 (51%) were assigned to saline. Each group received a median 1.9 l of fluid. The primary composite of major complications was observed in 5.8% of lactated Ringer's versus 6.1% of normal saline patients, with estimated average relative risk across the components of the composite of 1.16 (95% CI, 0.89 to 1.52; P = 0.261). The secondary outcome, postoperative acute kidney injury, Acute Kidney Injury Network stage I-III versus 0, occurred in 6.6% of lactated Ringer's patients versus 6.2% of normal saline patients, with an estimated relative risk of 1.18 (99.3% CI, 0.99 to 1.41; P = 0.009, significance criterion of 0.007). Absolute differences between the treatment groups for each outcome were less than 0.5%, an amount that is not clinically meaningful. CONCLUSIONS: In elective orthopedic and colorectal surgery patients, there was no clinically meaningful difference in postoperative complications with lactated Ringer's or saline volume replacement. Clinicians can reasonably use either solution intraoperatively.

Effect of Intravenous Acetaminophen on Postoperative Hypoxemia After Abdominal Surgery: The FACTOR Randomized Clinical Trial.

Importance: Opioid-induced ventilatory depression and hypoxemia is common, severe, and often unrecognized in postoperative patients. To the extent that nonopioid analgesics reduce opioid consumption, they may decrease postoperative hypoxemia. Objective: To test the hypothesis that duration of hypoxemia is less in patients given intravenous acetaminophen than those given placebo. Design, Setting, and Participants: Randomized, placebo-controlled, double-blind trial conducted at 2 US academic hospitals among 570 patients who were undergoing abdominal surgery, enrolled from February 2015 through October 2018 and followed up until February 2019. Interventions: Participants were randomized to receive either intravenous acetaminophen, 1 g (n = 289), or normal saline placebo (n = 291) starting at the beginning of surgery and repeated every 6 hours until 48 postoperative hours or hospital discharge, whichever occurred first. Main Outcomes and Measures: The primary outcome was the total duration of hypoxemia (hemoglobin oxygen saturation [Spo2] <90%) per hour, with oxygen saturation measured continuously for 48 postoperative hours. Secondary outcomes were postoperative opioid consumption, pain (0- 10-point scale; 0: no pain; 10: the most pain imaginable), nausea and vomiting, sedation, minimal alveolar concentration of volatile anesthetic, fatigue, active time, and respiratory function. Results: Among 580 patients randomized (mean age, 49 years; 48% women), 570 (98%) completed the trial. The primary outcome, median duration with Spo2 of less than 90%, was 0.7 (interquartile range [IQR], 0.1-5.1) minutes per hour among patients in the acetaminophen group and 1.1 (IQR, 0.1-6.6) minutes per hour among patients in the placebo group (P = .29), with an estimated median difference of -0.04 (95% CI,-0.18 to 0.11) minutes per hour. None of the 8 secondary end points differed significantly between the acetaminophen and placebo groups. Mean pain scores within initial 48 postoperative hours were 4.2 (SD, 1.8) in the acetaminophen group and 4.4 (SD, 1.8) in the placebo group (difference, -0.28; 95% CI, -0.71 to 0.15); median opioid use in morphine equivalents was 50 mg (IQR, 18-122 mg) and 58 mg (IQR, 24-151 mg) , respectively, with a ratio of geometric means of 0.86 (95% CI, 0.61-1.21). Conclusions and Relevance: Among patients who underwent abdominal surgery, use of postoperative intravenous acetaminophen, compared with placebo, did not significantly reduce the duration of postoperative hypoxemia over 48 hours. The study findings do not support the use of intravenous acetaminophen for this purpose. Trial Registration: ClinicalTrials.gov Identifier: NCT02156154.

Incidence, Severity, and Detection of Blood Pressure Perturbations after Abdominal Surgery: A Prospective Blinded Observational Study.

BACKGROUND: Intraoperative and postoperative hypotension are associated with myocardial and kidney injury and 30-day mortality. Intraoperative blood pressure is measured frequently, but blood pressure on surgical wards is usually measured only every 4 to 6 h, leaving long intervals during which hypotension and hypertension may be undetected. This study evaluated the incidence and severity of postoperative hypotension and hypertension in adults recovering from abdominal surgery and the extent to which serious perturbations were missed by routine vital-sign assessments. METHODS: Blood pressure was recorded at 1-min intervals during the initial 48 h in adults recovering from abdominal surgery using a continuous noninvasive monitor. Caregivers were blinded to these measurements and depended on routine vital-sign assessments. Hypotension and hypertension were characterized as time under and above various mean arterial pressure thresholds. RESULTS: Of 502 available patients, 312 patients with high-quality records were analyzed, with a median measurement time of 48 [interquartile range: 41, 48] postoperative hours. Nearly a quarter experienced an episode of mean arterial pressure of less than 70 mm Hg lasting at least 30 min (24%; 95% CI, 20%, 29%), and 18% had an episode of mean arterial pressure of less than 65 mm Hg lasting at least 15 min. Nearly half the patients who had mean arterial pressure of less than 65 mm Hg for at least 15 min (47%; 95% CI, 34%, 61%) were undetected by routine vital-sign assessments. Episodes of mean arterial pressure greater than 110 mm Hg lasting at least 30 min were observed in 42% (95% CI, 37%, 48%) of patients; 7% had mean arterial pressure greater than 130 mm Hg for at least 30 min, 96% of which were missed by routine assessments. Episodes of mean arterial pressure less than 65 mm Hg and mean arterial pressure greater than 110 mm Hg captured by routine vital-sign assessments but not by continuous monitoring occurred in 34 and 8 patients, respectively. CONCLUSIONS: Postoperative hypotension and hypertension were common, prolonged, profound, and largely undetected by routine vital-sign assessments in a cohort of adults recovering from abdominal surgery. Frequent or continuous blood pressure monitoring may detect hemodynamic perturbations more effectively and potentially facilitate treatment.

Methylprednisolone Does Not Reduce Acute Postoperative Pain After Cardiac Surgery: Subanalysis of a Randomized Clinical Trial.

BACKGROUND: Pain after cardiac surgery is largely treated with opioids, but their poor safety profile makes nonopioid medications attractive as part of multimodal pathways. Anti-inflammatory drugs reduce acute postoperative pain, but the role of steroids in reducing acute poststernotomy pain is unclear. We evaluated the association between the intraoperative administration of methylprednisolone and postoperative analgesia, defined as a composite of pain scores and opioid consumption, during the initial 24 hours after cardiac surgery. METHODS: We conducted a post hoc retrospective analysis of a large clinical trial in which adults having cardiac surgery were randomized 1:1 to receive 2 intraoperative doses of 250 mg IV methylprednisolone or placebo. Pain scores and opioid consumption were collected during the initial 24 hours after surgery. Methylprednisolone was considered to be associated with better pain control than placebo if proven noninferior (not worse) on both pain scores (defined a priori with delta of 1 point) and opioid consumption (delta of 20%) and superior to placebo in at least 1 of the 2 outcomes. This test was repeated in the opposite direction (testing whether placebo is better than methylprednisolone on postoperative pain management). RESULTS: Of 251 eligible patients, 127 received methylprednisolone and 124 received placebo. Methylprednisolone was noninferior to placebo on pain with difference in mean (CI) pain scores of -0.25 (-0.71 to 0.21); P < .001. However, methylprednisolone was not noninferior to placebo on opioid consumption (ratio of geometric means [CI]: 1.11 [0.64-1.91]; P = .37). Because methylprednisolone was not noninferior to placebo on both outcomes, we did not proceed to superiority testing based on the a priori stopping rules. Similar results were found when testing the opposite direction. CONCLUSIONS: In this post hoc analysis, we could not identify a beneficial analgesic effect after cardiac surgery associated with methylprednisolone administration. There are currently no data to suggest that methylprednisolone has significant analgesic benefit in adults having cardiac surgery.

Incidence of adverse events attributable to bupivacaine liposome injectable suspension or plain bupivacaine for postoperative pain in pediatric surgical patients: A retrospective matched cohort analysis.

BACKGROUND: Surgical wound infiltration with local anesthetics is common as part of multimodal analgesia and enhanced recovery pathways in pediatric surgical patients. Liposomal bupivacaine can provide up to 92 hours of pain relief, and was approved by the U.S Food and Drug Administration for local infiltration in adults. It is also commonly used by pediatric surgeons, but its safety profile in this age group has not been described. AIMS: The aim of this study was to describe the incidence of local anesthetic systemic toxicity syndrome in pediatric surgical patients receiving liposomal bupivacaine compared to plain bupivacaine for surgical wound infiltration. METHODS: We conducted a retrospective, single center, assessor blinded cohort study of pediatric surgical inpatients having open or laparoscopic surgery in the Cleveland Clinic between 2013 and 2017 and receiving wound infiltration with local anesthetics. We compared the incidence of local anesthetic systemic toxicity among those who received any dose of liposomal bupivacaine and those who received plain bupivacaine. Groups were matched 1:2 according to procedure type, age, and physical status score. Local anesthetic systemic toxicity was primarily defined as at least two signs or symptoms possibly related to anesthetic toxicity, as judged by two independent adjudicators blinded to the type of local anesthetic. A sensitivity analysis compared the incidence of a single sign/symptom possibly related to anesthetic toxicity. RESULTS: A total of 924 surgical cases were included in the final analysis (356 liposomal bupivacaine and 568 plain bupivacaine cases). The primary outcome did not occur in any patient. The sensitivity analysis found three cases in the liposomal bupivacaine group and two cases in the plain bupivacaine group having a single sign/symptom possibly related to local anesthetic administration (relative risk 2.4, 95% CI 0.4-14.0, P = 0.38). CONCLUSION: In a cohort of pediatric surgical patients receiving wound infiltration with either plain or liposomal bupivacaine, we identified no cases of local anesthetic systemic toxicity syndrome, and only few patients with any sign or symptom that could potentially be related to local anesthetic toxicity.

Pressure injury treatment by intermittent electrical stimulation (PROTECT-2): protocol for a multicenter randomized clinical trial.

BACKGROUND: Pressure ulcers account for a substantial fraction of hospital-acquired pathology, with consequent morbidity and economic cost. Treatments are largely focused on preventing further injury, whereas interventions that facilitate healing remain limited. Intermittent electrical stimulation (IES) increases local blood flow and redistributes pressure from muscle-bone interfaces, thus potentially reducing ulcer progression and facilitating healing. METHODS: The Pressure Injury Treatment by Intermittent Electrical Stimulation (PROTECT-2) trial will be a parallel-arm multicenter randomized trial to test the hypothesis that IES combined with routine care reduces sacral and ischial pressure injury over time compared to routine care alone. We plan to enroll 548 patients across various centers. Hospitalized patients with stage 1 or stage 2 sacral or ischial pressure injuries will be randomized to IES and routine care or routine care alone. Wound stage will be followed until death, discharge, or the development of an exclusion criteria for up to 3 months. The primary endpoint will be pressure injury score measured over time. DISCUSSION: Sacral and ischial pressure injuries present a burden to hospitalized patients with both clinical and economic consequences. The PROTECT-2 trial will evaluate whether IES is an effective intervention and thus reduces progression of stage 1 and stage 2 sacral and ischial pressure injuries. TRIAL REGISTRATION: ClinicalTrials.gov NCT05085288 Registered October 20, 2021.

Transversus abdominis plane block with liposomal bupivacaine versus continuous epidural analgesia for major abdominal surgery: The EXPLANE randomized trial.

OBJECTIVE: Compare transversus abdominis plane (TAP) blocks with liposomal bupivacaine were to epidural analgesia for pain at rest and opioid consumption in patients recovering from abdominal surgery. BACKGROUND: ERAS pathways suggest TAP blocks in preference to epidural analgesia for abdominal surgery. However, the relative efficacies of TAP blocks and epidural analgesia remains unknown. METHODS: Patients having major abdominal surgery were enrolled at six sites and randomly assigned 1:1 to thoracic epidural analgesia or bilateral/4-quadrant TAP blocks with liposomal bupivacaine. Intravenous opioids were used as needed. Non-inferiority margins were a priori set at 1 point on an 11-point pain numeric rating scale for pain at rest and at a 25% increase in postoperative opioid consumption. RESULTS: Enrollment was stopped per protocol at 3rd interim analysis after crossing an a priori futility boundary. 498 patients were analyzed (255 had TAP blocks and 243 had epidurals). Pain scores at rest in patients assigned to TAP blocks were significantly non-inferior to those given epidurals, with an estimated difference of 0.09 points (CI: -0.12, 0.30; noninferiority P < 0.001). Opioid consumption during the initial 3 postoperative days in TAP patients was not non-inferior to epidurals, with an estimated ratio of geometric means of 1.37 (CI: 1.05, 1.79; non-inferiority P = 0.754). However, the absolute difference was only 21 mg morphine equivalents over the 3 days. Patients with epidurals were more likely to experience mean arterial pressures <65 mmHg than those given TAP blocks: 48% versus 31%, P = 0.006. CONCLUSION: Pain scores at rest during the initial three days after major abdominal surgery were similar. Patients assigned to TAP blocks required more opioid then epidural patients but had less hypotension. Clinicians should reconsider epidural analgesia in patients at risk from hypotension. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02996227.

Renal injury after open versus laparoscopic non-cardiac surgery: a retrospective cohort analysis.

BACKGROUND: Laparoscopic surgical approaches enhance recovery, reduce postoperative pain, and shorten hospital length-of-stay. Nevertheless, increased intra-abdominal pressure is associated with decreased renal blood flow, renal hypoxia and acute kidney injury. When combined with Trendelenburg positioning, renal function may further deteriorate. We tested the primary hypothesis that the combination of laparoscopic surgical approach and Trendelenburg position is associated with larger reductions in estimated Glomerular Filtration Rate (eGFR) within the initial 48 postoperative hours compared to open surgery without Trendelenburg positioning. Secondarily, we tested, if laparoscopic procedures are associated with greater incidence of postoperative acute kidney injury. METHODS: Adults who had laparoscopic colorectal surgery in Trendelenburg position at the Cleveland Clinic Main Campus from 2009 to 2016 were propensity-matched to patients who had comparable open procedures. Patients with pre-existing renal impairment were excluded. RESULTS: Among 7,357 eligible patients, 1,846 laparoscopic cases with Trendelenburg were matched to 1,846 open cases. No association was found between laparoscopic approach and postoperative eGFR. A significant protective effect of the laparoscopic procedure on the odds of having AKI was found. Patients who had laparoscopic surgeries were an estimated 0.70 (95% CI 0.55, 0.90, pHolm-adj = 0.006) times as likely to have AKI as open surgical patients. CONCLUSION: Despite compelling potential mechanisms, laparoscopic approach with Trendelenburg position in adult colorectal surgeries did not worsen postoperative eGFR, and actually reduced postoperative acute kidney injury. Given the other advantages of laparoscopic surgery, the approach should not be avoided for concerns about renal injury.

Ethnic Differences in Analgesic Efficacy and Safety of Liposomal Bupivacaine Among Asian and Caucasian Surgical Patients: A Retrospective Matched-Cohort Analysis.

BACKGROUND: Extended-release local anesthetics allow for prolonged analgesia after a single administration. Although Asians demonstrate different pain thresholds than Caucasians, whether they have different postoperative local anesthetic analgesic effects has not been elucidated. OBJECTIVE: We aimed to compare the postoperative analgesic efficacy of liposomal bupivacaine on Asian and Caucasian adults, and the incidence of local anesthetic systemic toxicity (LAST) syndrome. METHODS: We conducted a retrospective, assessor-blinded cohort study of adult patients who received liposomal bupivacaine for surgery between 2012 and 2018. Asians and Caucasians were matched in a 1:1 ratio by clinical characteristics and surgery type. The primary outcome was pain management, defined as average pain score and opioid consumption during the initial 72 postoperative hours. The secondary outcome was the incidence of LAST syndrome. Reviewers were blinded to the ethnicity of the patient. RESULTS: After 1:1 propensity score matching, 130 Asians and 129 Caucasians were analyzed. All confounding variables were balanced, except for higher body mass index in the Asian group. Pain scores were lower (adjusted mean difference of -0.50 [97.5% CI, -0.98, -0.01]; superiority p = 0.011) and opioid consumption was not greater (geometric means ratio, 0.61 [97.5% CI, 0.36, 1.04]; non-inferiority p ＜ 0.001) in Asian patients compared to Caucasian patients. Only one Caucasian patient was judged as having a potential case of LAST syndrome. The length of hospital stay and the incidence of additional complications were not different between the groups. CONCLUSION: Asian adults receiving liposomal bupivacaine as part of multimodal perioperative analgesia demonstrated lower pain scores compared to matching Caucasians, despite not having greater opioid consumption.