Analgesic efficacy of PECS and serratus plane blocks after breast surgery: A systematic review,meta-analysis and trial sequential analysis

Study objectiveTo determine whether pectoral nerves (PECS) blocks provide effective postoperative analgesia when compared with no regional technique in patients undergoing breast surgery.DesignSystematic review, meta-analysis and trial sequential analysis.SettingOperating room, postoperative recovery area and ward, up to 24 postoperative hours.PatientsPatients undergoing breast surgery under general anaesthesia with either PECS block or no regional technique.InterventionsWe searched five electronic databases for randomized controlled trials comparing PECS block with no block or sham injection.MeasurementsThe primary outcome was rest pain scores (analogue scale, 0–10) at 2 h, analysed according to surgery (mastectomy vs other breast surgery) and regional technique (PECS 2 vs other blocks), among others. Secondary outcomes included morphine equivalent consumption, and rate of postoperative nausea and vomiting at 24 h.Main resultsSixteen trials including 1026 patients were identified. Rest pain scores at 2 h were decreased in the PECS blocks group, with a mean (95%CI) difference of −1.5 (−2.0, −1.0); I2 = 93%; p < 0.001, with no differences between surgery (mastectomy, mean difference [95%CI]: −1.8 [−2.4, −1.2], I² = 91%, p < 0.001; other breast surgery, mean difference [95%CI]: −1.1 [−2.1, −0.1], I² = 94%, p = 0.03; p for subgroup difference = 0.25), and regional technique (PECS 2, mean differences [95%CI]: −1.6 [−2.3, −1.0], I² = 94%, p < 0.001; other blocks, mean differences [95%CI]: −1.3 [−2.4, −0.1], I² = 74%, p = 0.04; p for subgroup difference = 0.57). The rate of postoperative nausea and vomiting was reduced from 30.8% (95%CI: 25.7%, 36.3%) to 18.7% (95%CI, 14.4%, 23.5%; p = 0.01). Similarly, secondary outcomes were significantly improved in the PECS blocks group. The overall quality of evidence was moderate-to-high.ConclusionsThere is moderate-to-high level evidence that PECS blocks provide postoperative analgesia after breast surgery when compared with no regional technique and reduce rate of PONV. This might provide the most benefit to those at high-risk of postoperative pain.     

Analgesic efficacy of PECS vs paravertebral blocks after radical mastectomy: A systematic review,meta-analysis and trial sequential analysis

Study objectiveDue to conflicting results published in the literature regarding the analgesic superiority between the paravertebral block and the PECS block, the study objective is to determine which one should be the first line analgesic treatment after radical mastectomy.DesignSystematic review, meta-analysis and trial sequential analysis.SettingOperating room, postoperative recovery area and ward, up to 24 postoperative hours.PatientsPatients scheduled for radical mastectomy under general anaesthesia.InterventionsWe searched five electronic databases for randomized controlled trials comparing any PECS block with a paravertebral block.MeasurementsThe primary outcome was rest pain score (0−10) at 2 postoperative hours, analyzed according to the combination with axillary dissection or not, to account for heterogeneity. Secondary outcomes included rest pain scores, cumulative intravenous morphine equivalents consumption and rate of postoperative nausea and vomiting at 24 postoperative hours.Main resultsEight trials including 388 patients were identified. Rest pain scores at 2 postoperative hours were decreased in the PECS block group, with a mean difference (95%CI) of −0.4 (−0.7 to −0.1), I² = 68%, p = 0.01, and a significant subgroup difference observed between radical mastectomy with (mean difference [95%CI]: 0.0 [−0.2 to 0.2], I² = 0%, p = 1.00), or without axillary dissection (mean difference [95%CI]: −0.7 [−1.1 to −0.4], I² = 40%, p < 0.001; p for subgroup difference < 0.001). All secondary pain-related outcomes were similar between groups. The overall quality of evidence was low.ConclusionsThere is low quality evidence that a PECS block provides marginal postoperative analgesic benefit after radical mastectomy at 2 postoperative hours only, when compared with a paravertebral block, and not beyond.Clinical trial number: PROSPERO – registration number: CRD42019131555.     

Adverse side-effects of dexamethasone in surgical patients – an abridged Cochrane systematic review

In the peri-operative period, dexamethasone is widely and effectively used for prophylaxis of postoperative nausea and vomiting. The objective of this meta-analysis was to assess the adverse effects of an incidental steroid load of dexamethasone in adult surgical patients. We searched in MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and the Web of Science for randomised controlled trials comparing an incidental steroid load of dexamethasone with a control intervention in adult patients undergoing surgery. Two review authors independently screened studies for eligibility, extracted data and assessed all included studies for bias. Our primary outcomes were postoperative systemic or wound infection, delayed wound healing and glycaemic response within 24 h. We included 37 studies in this meta-analysis. The pooled results found no evidence that dexamethasone increased the risk of a postoperative wound infection, Peto OR (95%CI) 1.01 (0.80–1.27); 4603 participants, 26 studies; I² = 32%; moderate-quality evidence. Whether dexamethasone influenced wound healing was unclear due to the large confidence intervals, Peto OR (95%CI) 0.99 (0.28–3.43); 1072 participants, 8 studies; I² = 0%; low-quality evidence. Dexamethasone produced a mild increase in glucose levels among participants without diabetes during the first 12 h after surgery, mean difference (95%CI) 0.7 mmol.l⁻¹(0.3–1.2) 10 studies; 595 participants; I² = 50%; low-quality evidence. This article is an abridged version of a Cochrane Review.     

A systematic review of sugammadex vs neostigmine for reversal of neuromuscular blockade

We reviewed systematically sugammadex vs neostigmine for reversing neuromuscular blockade. We included 17 randomised controlled trials with 1553 participants. Sugammadex reduced all signs of residual postoperative paralysis, relative risk (95% CI) 0.46 (0.29–0.71), p = 0.0004 and minor respiratory events, relative risk (95% CI) 0.51 (0.32–0.80), p = 0.0034. There was no difference in critical respiratory events, relative risk (95% CI) 0.13 (0.02–1.06), p = 0.06. Sugammadex reduced drug‐related side‐effects, relative risk (95% CI) 0.72 (0.54–0.95), p = 0.02. There was no difference in the rate of postoperative nausea or the rate of postoperative vomiting, relative risk (95% CI) 0.94 (0.79–1.13), p = 0.53, and 0.87 (0.65–1.17), p = 0.36 respectively.     

Analgesic impact of intra-operative opioids vs. opioid-free anaesthesia: a systematic review and meta-analysis

Opioids are administered peri-operatively for postoperative analgesia, and intra-operatively to control the sympathetic response to surgical stimuli, frequently as a surrogate for presumed pain. However, opioid use during surgery is a matter of dispute in contemporary practice and carries the risk of side-effects such as postoperative nausea and vomiting. This meta-analysis investigated whether opioid-inclusive, compared with opioid-free anaesthesia, would reduce postoperative pain, without increasing the rate of postoperative nausea and vomiting. The electronic databases Medline and PubMed were searched until June 2018. We included trials investigating pain outcomes and comparing any type of intra-operative opioid administration with placebo injection or no intra-operative opioid. Most meta-analyses were performed using a random effects model. We rated the quality of evidence for each outcome. The primary outcome was pain score at rest (analogue scale, 0–10) at two postoperative hours. Our secondary outcomes included the rate of postoperative nausea and vomiting within the first 24 postoperative hours and length of stay in the recovery area. Twenty-three randomised controlled trials, including 1304 patients, were identified. Pain scores at rest at two postoperative hours were equivalent in the opioid-inclusive and opioid-free groups with a mean difference (95%CI) of 0.2 (−0.2 to 0.5), I² = 83%, p = 0.38 and a high quality of evidence. Similarly, there was high-quality evidence that the rate of postoperative nausea and vomiting was reduced in the opioid-free group, with a risk ratio (95%CI) of 0.77 (0.61–0.97), I² = 16%, p = 0.03 and high-quality evidence for a similar length of stay in the recovery area, the mean difference (95%CI) being 0.6 (−8.2 to 9.3), min, I² = 60%, p = 0.90. As there is strong evidence that opioid-inclusive anaesthesia does not reduce postoperative pain, but is associated with more postoperative nausea and vomiting, when compared with opioid-free anaesthesia, we suggest that anaesthetists should reconsider their intra-operative opioid choices on a case-by-case basis.     

A randomised controlled trial of intravenous dexmedetomidine added to dexamethasone for arthroscopic rotator cuff repair and duration of interscalene block

Prolongation of peripheral nerve blockade by intravenous dexamethasone may be extended by intravenous dexmedetomidine. We randomly allocated 122 participants who had intravenous dexamethasone 0.15 mg.kg⁻¹ before interscalene brachial plexus block for day-case arthroscopic rotator cuff repair to intravenous saline (62 participants) or intravenous dexmedetomidine 1 μg.kg⁻¹ (60 participants). The primary outcome was time from block to first oral morphine intake during the first 48 postoperative hours. Fifty-nine participants reported taking oral morphine, 25/62 after placebo and 34/60 after dexmedetomidine, p = 0.10. The time to morphine intake was shorter after dexmedetomidine, hazard ratio (95%CI) 1.68 (1.00–2.82), p = 0.049. Median (IQR [range]) morphine doses were 0 (0–12.5 [0–50]) mg after control vs. 10 (0–30 [0–50]) after dexmedetomidine, a difference (95%CI) of 7 (0–10) mg, p = 0.056. There was no effect of dexmedetomidine on pain at rest or on movement. Intra-operative hypotension was recorded for 27/62 and 50/60 participants after placebo vs. dexmedetomidine, respectively, p < 0.001. Other outcomes were similar, including durations of sensory and motor block. In conclusion, dexmedetomidine shortened the time to oral morphine consumption after interscalene block combined with dexamethasone and caused intra-operative hypotension.     

Efficacy of erector spinae plane block for analgesia in breast surgery: a systematic review and meta-analysis

The erector spinae plane block is a new regional anaesthesia technique that provides truncal anaesthesia for breast surgery. This systematic review and meta-analysis was undertaken to determine if the erector spinae plane block is effective at reducing pain scores and opioid consumption after breast surgery. This study also evaluated the outcomes of erector spinae plane blocks compared with other regional blocks. PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov were searched. We included randomised controlled trials reporting the use of the erector spinae plane block in adult breast surgery. Risk of bias was assessed with the revised Cochrane risk-of-bias tool. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework was used to assess trial quality. Thirteen randomised controlled trials (861 patients; 418 erector spinae plane block, 215 no blocks, 228 other blocks) were included. Erector spinae plane block reduced postoperative pain compared with no block: at 0-2 hours (mean difference (95% CI) −1.63 (−2.97 to −0.29), 6 studies, 329 patients, high-quality evidence, I² = 98%, p = 0.02); at 6 hours (mean difference (95% CI) −0.90 (−1.49 to −0.30), 5 studies, 250 patients, high-quality evidence, I² = 91%, p = 0.003); at 12 hours (mean difference (95% CI) −0.46 (−0.67 to −0.25), 5 studies, 250 patients, high-quality evidence, I² = 58%, p < 0.0001); and at 24 hours (mean difference (95% CI) −0.50 (−0.70 to −0.30), 6 studies, 329 patients, high-quality evidence, I² = 76%, p < 0.00001). Compared with no block, erector spinae plane block also showed significantly lower postoperative oral morphine equivalent requirements (mean difference (95% CI) −21.55mg (−32.57 to −10.52), 7 studies, 429 patients, high-quality evidence, I² = 99%, p = 0.0001). Separate analysis of studies comparing erector spinae plane block with pectoralis nerve block and paravertebral block showed that its analgesic efficacy was inferior to pectoralis nerve block and similar to paravertebral block. The incidence of pneumothorax was 2.6% in the paravertebral block group; there were no reports of complications of the other blocks. This review has shown that the erector spinae plane block is more effective at reducing postoperative opioid consumption and pain scores up to 24 hours compared with general anaesthesia alone. However, it was inferior to the pectoralis nerve block and its efficacy was similar to paravertebral block. Further evidence, preferably from properly blinded trials, is required to confirm these findings.     

The impact of crystalloid versus colloid fluids on postoperative nausea and vomiting: A systematic review and meta-analysis of randomized controlled trials

Study objectiveEvidence suggests that administering appropriate volumes of perioperative fluid replacement therapies can decrease the incidence of postoperative nausea and vomiting (PONV). However, the relative effects of colloids and crystalloids on PONV are still unclear. The objective of this systematic review was to determine whether administering colloids to adults undergoing noncardiac surgery significantly reduces PONV incidence and rescue antiemetic use, compared with administering crystalloids.DesignThis study has been registered in PROSPERO (ID: CRD42016036174). We performed a meta-analysis of randomized controlled trials that compared the incidence of PONV and rescue antiemetic use in surgical patients randomized to receive colloid or crystalloid fluids. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Heterogeneity was explored through I² statistics.PatientsNine randomized trials that included a total of 843 surgical patients met the inclusion criteria.MeasurementsThe primary outcome of interest was the incidence of overall PONV. Secondary outcomes included the incidence of postoperative nausea (PON), postoperative vomiting (POV), and rescue antiemetic use.Main resultsCompared with crystalloid fluids, perioperative colloid administration did not reduce the incidence of overall PONV (RR 0.802; 95% CI: 0.561, 1.145; I² = 57.168%). However, the colloid infusion group (RR 0.625; 95% CI: 0.440, 0.888) had reduced PONV compared with the crystalloid infusion group (RR 1.244; 95% CI: 0.742, 2.085), in the subgroup with anesthesia duration >3 h and who underwent major surgery. Meta-regression analysis also showed that the slope was significant (p = 0.04215) for duration of anesthesia.ConclusionsColloid administration reduced the incidence of PONV in adults undergoing elective, noncardiac, major surgery under general anesthesia for >3 h. However, clinical studies performed in larger cohorts are required to determine the impact of colloids on PONV.     

Postoperative outcomes in older surgical patients with preoperative cognitive impairment: A systematic review and meta-analysis

Study objectiveTo determine the effect of cognitive impairment (CI) and dementia on adverse outcomes in older surgical patients.DesignA systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs). Various databases were searched from their inception dates to March 8, 2021.SettingPreoperative assessment.PatientsOlder patients (≥ 60 years) undergoing non-cardiac surgery.MeasurementsOutcomes included postoperative delirium, mortality, discharge to assisted care, 30-day readmissions, postoperative complications, and length of hospital stay. Effect sizes were calculated as Odds Ratio (OR) and Mean Difference (MD) based on random effect model analysis. The quality of included studies was assessed using the Cochrane Risk Bias Tool for RCTs and Newcastle-Ottawa Scale for observational cohort studies.ResultsFifty-three studies (196,491 patients) were included. Preoperative CI was associated with a significant risk of delirium in older patients after non-cardiac surgery (25.1% vs. 10.3%; OR: 3.84; 95%CI: 2.35, 6.26; I²: 76%; p < 0.00001). Cognitive impairment (26.2% vs. 13.2%; OR: 2.28; 95%CI: 1.39, 3.74; I²: 73%; p = 0.001) and dementia (41.6% vs. 25.5%; OR: 1.96; 95%CI: 1.34, 2.88; I²: 99%; p = 0.0006) significantly increased risk for 1-year mortality. In patients with CI, there was an increased risk of discharge to assisted care (44.7% vs. 38.3%; OR 1.74; 95%CI: 1.05, 2.89, p = 0.03), 30-day readmissions (14.3% vs. 10.8%; OR: 1.36; 95%CI: 1.00, 1.84, p = 0.05), and postoperative complications (40.7% vs. 18.8%; OR: 1.85; 95%CI: 1.37, 2.49; p < 0.0001).ConclusionsPreoperative CI in older surgical patients significantly increases risk of delirium, 1-year mortality, discharge to assisted care, 30-day readmission, and postoperative complications. Dementia increases the risk of 1-year mortality. Cognitive screening in the preoperative assessment for older surgical patients may be helpful for risk stratification so that appropriate management can be implemented to mitigate adverse postoperative outcomes.     

Intra-operative analgesia with remifentanil vs. dexmedetomidine: a systematic review and meta-analysis with trial sequential analysis

Intra-operative remifentanil is associated with increased postoperative analgesic requirements and opioid consumption. Dexmedetomidine has characteristics suggesting it may substitute for intra-operative remifentanil during general anaesthesia, but existing literature has reported conflicting results. We undertook this meta-analysis to investigate whether general anaesthesia including dexmedetomidine would result in less postoperative pain than general anaesthesia including remifentanil. The MEDLINE and PubMed electronic databases were searched up to October 2018. Only randomised trials including patients receiving general anaesthesia and comparing dexmedetomidine with remifentanil administration were included. Meta-analyses were performed mostly employing a random effects model. The primary outcome was pain score at rest (visual analogue scale, 0–10) at two postoperative hours. The secondary outcomes included: pain score at rest at 24 postoperative hours; opioid consumption at 2 and 24 postoperative hours; and rates of hypotension, bradycardia, shivering and postoperative nausea and vomiting. Twenty-one randomised trials, including 1309 patients, were identified. Pain scores at rest at two postoperative hours were lower in the dexmedetomidine group, with a mean difference (95%CI) of −0.7 (−1.2 to −0.2), I² = 85%, p = 0.004, and a moderate quality of evidence. Secondary pain outcomes were also significantly better in the dexmedetomidine group. Rates of hypotension, shivering and postoperative nausea and vomiting were at least twice as frequent in patients who received remifentanil. Time to analgesia request was longer, and use of postoperative morphine and rescue analgesia were less, with dexmedetomidine, whereas episodes of bradycardia were similar between groups. There is moderate evidence that intra-operative dexmedetomidine during general anaesthesia improves pain outcomes during the first 24 postoperative hours, when compared with remifentanil, with fewer side effects.     

Intravenous dexamethasone for prophylaxis of postoperative nausea and vomiting after administration of long‐acting neuraxial opioids: a systematic review and meta‐analysis

Long‐acting neuraxial opioids provide excellent analgesia after surgery, but are associated with higher rates of postoperative nausea and vomiting. Dexamethasone effectively prevents postoperative nausea and vomiting after general anaesthesia, but its value in patients receiving long‐acting neuraxial opioids is undetermined. Therefore, the objective of this meta‐analysis was to assess the prophylactic anti‐emetic efficacy of intravenous (i.v.) dexamethasone in this population. The study methodology followed the PRISMA statement guidelines. The primary outcome was the need for rescue anti‐emetics during the first 24 postoperative hours, analysed according to the dose of dexamethasone (low‐dose 2.5–5.0 mg; intermediate dose 6.0–10.0 mg), timing of administration (beginning or end of surgery) and route of long‐acting opioid administration (intrathecal or epidural). Additionally, the rates of complications (restlessness, infection, hyperglycaemia) were sought. Thirteen trials were identified, representing a total of 1111 patients. When compared with placebo, intravenous dexamethasone reduced the need for rescue anti‐emetics (risk ratio (95%CI) 0.44 (0.35–0.56); I² = 43%; p < 0.00001; quality of GRADE evidence: moderate), without differences between dexamethasone doses (p for sub‐group difference = 0.67), timing of administration (p for sub‐group difference = 0.32) or route of long‐acting opioid (p for sub‐group difference = 0.10). No patients developed infection or restlessness among trials that sought these complications. No trial measured blood glucose levels. In conclusion, there is enough evidence to state that intravenous dexamethasone provides effective anti‐emetic prophylaxis during the first 24 postoperative hours in patients who receive long‐acting neuraxial opioids.     

The comparative efficacy and safety of sugammadex and neostigmine in reversing neuromuscular blockade in adults. A Cochrane systematic review with meta‐analysis and trial sequential analysis

We compared the efficacy and safety of sugammadex and neostigmine in reversing neuromuscular blockade in adults. Our outcomes were: recovery time from second twitch to train‐of‐four ratio > 0.9; recovery time from post‐tetanic count 1–5 to train‐of‐four ratio > 0.9; and risk of composite adverse and serious adverse events. We searched for randomised clinical trials irrespective of publication status and date, blinding status, outcomes reported or language. We included 41 studies with 4206 participants. Time to reversal of neuromuscular blockade from second twitch to a train‐of‐four ratio > 0.9 was 2.0 min with sugammadex 2 mg.kg^?1 and 12.9 min with neostigmine 0.05 mg.kg^?1, with a mean difference (MD) (95%CI)) of 10.2 (8.5–12.0) (I² = 84%, 10 studies, n = 835, Grades of Recommendation, Assessment, Development and Evaluation (GRADE): moderate quality). Time to reversal of neuromuscular blockade from a post‐tetanic count of 1–5 to a train‐of‐four ratio > 0.9 was 2.9 min with sugammadex 4 mg.kg^?1 and 48.8 min with neostigmine 0.07 mg.kg^?1, with a MD (95%CI) of 45.8 (39.4–52.2) (I² = 0%, 2 studies, n = 114, GRADE: low quality). There were significantly fewer composite adverse events in the sugammadex group compared with neostigmine, with a risk ratio (95%CI) of 0.60 (0.49–0.74) (I² = 40%, 28 studies, n = 2298, number needed to treat (NNT): 8, GRADE: moderate quality). Specifically, the risk of bradycardia (RR (95%CI) 0.16 (0.07–0.34), n = 1218, NNT: 14, GRADE: moderate quality), postoperative nausea and vomiting (RR (95%CI) 0.52 (0.28–0.97), n = 389, NNT: 16, GRADE: low quality) and overall signs of postoperative residual paralysis (RR (95%CI) 0.40 (0.28–0.57), n = 1474, NNT: 13, GRADE: moderate quality) were all reduced. There was no significant difference regarding the risk of serious adverse events (RR 0.54, 95%CI 0.13–2.25, I² = 0%, n = 959, GRADE: low quality). Sugammadex reverses neuromuscular blockade more rapidly than neostigmine and is associated with fewer adverse events.     

Prophylactic phenylephrine for caesarean section under spinal anaesthesia: systematic review and meta‐analysis

We conducted a systematic review to determine the harm and benefit associated with prophylactic phenylephrine for caesarean section under spinal anaesthesia. We included 21 randomised controlled trials with 1504 women. The relative risk (95% CI) of hypotension with phenylephrine infusion – as defined by authors – before delivery was 0.36 (0.18–0.73) vs placebo, p = 0.004; 0.58 (0.39–0.88) vs an ephedrine infusion, p = 0.009; and 0.73 (0.55–0.96) when added to an ephedrine infusion, p = 0.02. After delivery, the relative risks of hypotension and nausea and vomiting with phenylephrine compared with placebo were 0.37 (0.19–0.71), p = 0.003, and 0.39 (0.17–0.91), p = 0.03, respectively. There was no evidence that hypertension, bradycardia or neonatal endpoints were affected. Phenylephrine reduced the risk for hypotension and nausea and vomiting after spinal doses of bupivacaine generally exceeding 8 mg, but there was no evidence that it reduced other maternal or neonatal morbidities.     

The effect of a low-dose naloxone infusion on the incidence of respiratory depression after intrathecal morphine administration for major open hepatobiliary surgery: a randomised controlled trial

Intrathecal morphine is an analgesic option for major hepatopancreaticobiliary procedures but is associated with a risk of respiratory depression. We hypothesised that a postoperative low-dose naloxone infusion would reduce the incidence of respiratory depression without an increase in pain scores. Patients scheduled for major open hepatopancreaticobiliary surgery and who were receiving 10 μg.kg⁻¹ intrathecal morphine were eligible for inclusion. Patients were allocated randomly to receive a postoperative infusion of naloxone 5 μg.kg⁻¹.h⁻¹ (naloxone group) or saline at an identical infusion rate (control group) until the morning after surgery. Clinicians, nursing staff and patients were blinded to group allocation. The primary outcome measure was the incidence of respiratory depression (respiratory rate < 10 breaths.min⁻¹ and/or oxygen saturation < 90%). Secondary outcome measures included: arterial partial pressure of carbon dioxide; pain score; requirement for supplemental analgesic; and incidence of nausea and vomiting, pruritus and sedation. In total, data from 95 patients (48 in the naloxone group and 47 in the control group) were analysed. The incidence of respiratory depression was lower in the naloxone group compared with the control group (10/48 vs. 21/47 patients, respectively; p = 0.037, relative risk 0.47 (95%CI 0.25–0.87). Maximum pain scores were greater for patients allocated to the naloxone group compared with control (median 5 (95%CI 4–6) vs. 4 (95%CI 2–4), respectively; p < 0.001). A low-dose naloxone infusion decreases the incidence of respiratory depression following intrathecal morphine administration in patients having major hepatopancreaticobiliary surgery at the expense of a small increase in postoperative pain.     

Epidural vs. transversus abdominis plane block for abdominal surgery – a systematic review,meta-analysis and trial sequential analysis

Traditionally, pain relief for abdominal surgery has centred on epidural analgesia, but transversus abdominis plane block is increasingly being used. Our aim was to compare the analgesic efficacy and the side-effect profile of transversus abdominis plane block with epidural analgesia in a systematic review with meta-analysis and trial sequential analysis. After a systematic search of the electronic databases, we identified 18 randomised controlled trials with 1220 patients. Confirmed by trial sequential analysis, our first co-primary outcome, postoperative pain score at rest at 12 h, was decreased by a mean difference (95%CI) of 0.69 (0.12–1.27; p = 0.02) with epidural analgesia compared with transversus abdominis plane block, with the quality of evidence graded as low. No difference was found for the second co-primary outcome, postoperative pain score at rest at 24 h, with the quality of evidence rated as very low. Relative to transversus abdominis plane block, epidural analgesia further reduced the need for intravenous morphine-equivalent consumption during the 0–24 h interval by a mean difference (95%CI) of 5.91 mg (2.34–9.49; p = 0.001) at the expense of an increased incidence of hypotension at 72 h, with a risk ratio (95%CI) of 5.88 (2.08–16.67; p < 0.001). Our meta-analysis was limited by detection and performance bias, significant statistical heterogeneity and publication bias. In view of the minimal clinically important difference in postoperative pain scores, epidural analgesia was interpreted to not be clinically different to transversus abdominis plane block after abdominal surgery. With transversus abdominis plane block, the increase in intravenous morphine-equivalent consumption at 24 h should be balanced against the decreased risk of hypotension at 72 h. In choosing between epidural analgesia and transversus abdominis plane block, potential benefits should be balanced against the reported risk of harm, although the confidence in the evidence varied, underlining the uncertainty in our estimates.     

Dynamic predictive model for postoperative nausea and vomiting for intravenous fentanyl patient-controlled analgesia

Postoperative nausea and vomiting is the most common side-effect of opioid-based intravenous patient-controlled analgesia. Apfel's simplified risk score is popular but it has some limitations. We developed and validated a dynamic predictive model for nausea or vomiting up to 48 postoperative hours, available as an online web application. Fentanyl was used by 22,144 adult patients for analgesia after non-cardiac surgery under general anaesthesia: we randomly divided them into development (80%) and validation (20%) cohorts, repeated 100 times. We used linear discriminant analysis to select variables for multivariate logistic regression. The incidences of postoperative nausea or vomiting were: 0–48 h, 5691/22,144 (26%); 0–6 h, 2749/22,144 (12%); 6–12 h, 2687/22,144 (12%); 12–18 h, 2624/22,144 (12%); 18–24 h, 1884/22,144 (9%); and 24–48 h, 1082/22,144 (5%). The median (95%CI) area under the receiver operating characteristic curve was 0.72 (0.71–0.73) up to 48 postoperative hours compared with 0.65 (0.64–0.66) for the Apfel model, p < 0.001. The equivalent areas for 0–6 h, 6–12 h, 12–18 h, 18–24 h and 24–48 h were: 0.70 (0.69–0.72); 0.71 (0.69–0.73); 0.69 (0.68–0.71); 0.70 (0.67–0.72); and 0.69 (0.66–0.71), respectively. Our web application allows clinicians to calculate incidences of nausea and vomiting in patients receiving intravenous fentanyl for patient-controlled analgesia.     

A randomised controlled trial of dexmedetomidine for delirium in adults undergoing heart valve surgery

Dexmedetomidine might reduce delirium after cardiac surgery. We allocated 326 participants to an infusion of dexmedetomidine at a rate of 0.6 μg kg⁻¹ for 10 min and then at 0.4 μg.kg⁻¹.h⁻¹ until the end of surgery; 326 control participants received comparable volumes of saline. We detected delirium in 98/652 (15%) participants during the first seven postoperative days: 47/326 after dexmedetomidine vs. 51/326 after placebo, p = 0.62, adjusted relative risk (95%CI) 0.86 (0.56–1.33), p = 0.51. Postoperative renal impairment (Kidney Disease Improving Global Outcomes stages 1, 2 and 3) was detected in 46, 9 and 2 participants after dexmedetomidine and 25, 7 and 4 control participants, p = 0.040. Intra-operative dexmedetomidine infusion did not reduce the incidence of delirium after cardiac valve surgery but might impair renal function.     

Local anaesthetic delivery regimens for peripheral nerve catheters: a systematic review and network meta-analysis

There are numerous possible techniques for delivering local anaesthetic through peripheral nerve catheters. These include continuous infusions, patient-controlled boluses and programmed intermittent boluses. The optimal delivery regimen of local anaesthetic is yet to be conclusively established. In this review, we identified prospective trials of delivery regimens through peripheral nerve catheters. Our primary outcome was visual analogue scale scores for pain at 48 h. Secondary outcomes were: visual analogue scores at 24 h; patient satisfaction scores; rescue opioid use; local anaesthetic consumption; and nausea and vomiting. Network meta-analysis was used to compare these outcomes. Predefined sub-group analyses were performed. Thirty-three studies enrolling 1934 participants were included. In comparison with continuous infusion, programmed intermittent boluses improved visual analogue pain scores at both 48 and 24 h, the weighted mean difference (95%CI) being −0.63 (−1.12 to −0.14), p = 0.012 and −0.48 (−0.92 to −0.03), p = 0.034, respectively. Programmed intermittent boluses also improved satisfaction scores, the weighted mean difference (95%CI) being 0.70 (0.10–1.31), p = 0.023, and reduced rescue opioid use, the weighted mean difference (95%CI) in oral morphine equivalent at 24 h being −23.84 mg (−43.90 mg to −3.77 mg), p = 0.020. Sub-group analysis revealed that these findings were mostly confined to lower limb and truncal catheter studies; there were few studies of programmed intermittent boluses for upper limb catheters. Programmed intermittent boluses may provide optimal delivery of a local anaesthetic through peripheral nerve catheters. Further research is warranted, particularly to delineate the differences between upper and lower limb catheter locations, which will help clarify the clinical relevance of these findings.     

Evidence for compromised data integrity in studies of liberal peri-operative inspired oxygen

In 2016 the World Health Organization recommended intra-operative ventilation with 80% inspired oxygen to reduce surgical site infection rates, based upon a meta-analysis of 15 randomised controlled trials, of which two were by Mario Schietroma's research group. Five trials by this group have been retracted for duplication, plagiarism, statistical error and lack of ethical approval. We analysed 40 papers by this group: 24 randomised controlled trials (5064 participants) and 16 observational studies (1847 patients). There was evidence that data integrity was compromised in 38 out of the 40 analysed papers. The distribution of baseline characteristics in randomised controlled trials was unlikely, p = 1.5 × 10⁻⁸: continuous variables within trials were heterogeneous, p = 1.9 × 10⁻⁹, and categorical variables were homogeneous, p = 8.5 × 10⁻²⁰. Effects of interventions varied less than expected between studies: for categorical variables, for instance postoperative wound infection, p < 1 × 10⁻⁷, and for continuous variables, for instance HLA-DR concentration, p = 0.00001. Of 184 calculable p values, for baseline variables or results, 179 (98%) were incorrect, ranging from three orders of magnitude too small to 10 orders of magnitude too large. Twenty-one graphs occurred 81 times in 23 out of 40 papers. Liberal peri-operative oxygen did not reduce surgical site infection in a meta-analysis of 20 trials that excluded seven trials by Mario Schietroma and colleagues (odds ratio (95%CI) 0.89 (0.73-1.08); p = 0.23). An update by the World Health Organization has now excluded trials of liberal oxygen by Schietroma's group, four of which have not been retracted. We conclude that Mario Schietroma's work should not inform practice until investigated.     

Peri-articular infiltration analgesia for shoulder surgery: a systematic review and meta-analysis

Effective analgesic alternatives to interscalene brachial plexus block are sought for shoulder surgery. Peri-articular infiltration analgesia is a novel, less invasive technique, but evidence surrounding its use is unclear. This systematic review and meta-analysis aims to evaluate the utility of peri-articular infiltration analgesia in shoulder surgery. We searched literature for trials comparing peri-articular infiltration analgesia with control or with interscalene brachial plexus block. Control groups received no intervention, placebo or systemic opioids. The primary outcome was cumulative oral morphine equivalent consumption during the first 24 h postoperatively. Secondary outcomes included: rest pain scores up to 48 h; risk of side-effects; and durations of post-anaesthetic care unit and hospital stay. Data were pooled with random-effects modelling. Seven trials (383 patients) were included. Compared with control, peri-articular infiltration analgesia reduced 24-h oral morphine consumption by a mean difference (95%CI) of −38.0 mg (−65.5 to −10.5; p = 0.007). It also improved pain scores up to 6 h, 36 h and 48 h, with the greatest improvement observed at 0 h (−2.4 (−2.7 to −1.6); p < 0.001). Peri-articular infiltration analgesia decreased postoperative nausea and vomiting by an odds ratio (95%CI) of 0.3 (0.1–0.7; p = 0.006). In contrast, peri-articular infiltration analgesia was not different from interscalene brachial plexus block for analgesic consumption, pain scores or side-effects. This review provides moderate evidence supporting peri-articular infiltration for postoperative analgesia following shoulder surgery. The absence of difference between peri-articular infiltration analgesia and interscalene brachial plexus block for analgesic outcomes suggests that these interventions are comparable, but further trials are needed to support this conclusion and identify the optimal peri-articular infiltration technique.