Heterogeneity in meta-analyses. Comparing apples and oranges?

Intravenous versus perineural dexamethasone to prolong analgesia after interscalene brachial plexus block: a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

The efficacy of perineural vs intravenous dexamethasone as a local anaesthetic adjunct to increase duration of analgesia could be particular to specific peripheral nerve blocks because of differences in systemic absorption depending on the injection site. Given this uncertainty, we performed a systematic review with meta-analysis and trial sequential analysis comparing dexamethasone administered perineurally or intravenously combined with local anaesthetic for interscalene brachial plexus block.

METHODS

Following a search of various electronic databases, we included 11 trials (1145 patients). The primary outcome was the duration of analgesia defined as the time between peripheral nerve block or onset of sensory blockade and the time to first analgesic request or initial report of pain.

RESULTS

The primary outcome, duration of analgesia, was greater in the perineural dexamethasone group, with a mean difference (95% confidence interval) of 122 (62-183) min, I2=73%, P<0.0001. Trial sequential analysis indicated that firm evidence had been reached. The quality of evidence was downgraded to low, mainly because of moderate inconsistency and serious publication bias. No significant differences were present for any of the secondary outcomes, except for onset time of sensory and motor blockade and resting pain score at 12 h, but the magnitude of differences was not clinically relevant.

CONCLUSIONS

There is low-quality evidence that perineural administration of dexamethasone as a local anaesthetic adjunct increases duration of analgesia by an average of 2 h compared with intravenous injection for interscalene brachial plexus block. Given the limited clinical relevance of this difference, the off-label use of perineural administration, and the risk of drug crystallisation, we recommend intravenous dexamethasone administration.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023466147).

Efficacy and safety of intrathecal diamorphine: a systematic review and meta-analysis with meta-regression and trial sequential analysis

BACKGROUND

Intrathecal diamorphine is believed to provide postoperative analgesia but is associated with adverse effects such as nausea and vomiting. There is little evidence of synthesis regarding intrathecal diamorphine in the contemporary literature. We performed a systematic review, meta-analysis with meta-regression and trial sequential analysis to determine the magnitude of intrathecal diamorphine efficacy and safety.

METHODS

We systematically searched the literature for trials comparing intrathecal diamorphine with a control group in patients undergoing all types of surgery. The primary efficacy and safety outcomes were intravenous morphine consumption and incidence of postoperative nausea and vomiting at 24 h following surgery, respectively.

RESULTS

Twelve trials were identified, which included data for 712 patients. Intrathecal doses of diamorphine ranged from 100 μg to 2500 μg. Intravenous morphine consumption at 24 h postoperatively was significantly reduced in the intrathecal diamorphine group, with a mean difference (95%CI) of -8 mg (-11 to -6), I2 = 93%, p < 0.001. There was a significant difference between three intrathecal diamorphine dosing subgroups but without correlation: mean differences (95%CI) -1 mg (-3-0), -26 mg (-40 to -11) and -6 mg (-15-4) in patients receiving doses of 0-200 μg, 201-400 μg and > 400 μg, respectively (p = 0.003). Intrathecal diamorphine increased postoperative nausea and vomiting with a risk ratio (95%CI) of 1.37 (1.19-1.58), I2 = 7%, p < 0.001. There were no differences in postoperative nausea and vomiting between the three intrathecal diamorphine dosing subgroups. There was no correlation observed with meta-regression of the primary efficacy and safety outcomes. The quality of evidence for all outcomes was very low.

CONCLUSION

There is very low level of evidence that intrathecal diamorphine provides effective analgesia after surgery, while increasing postoperative nausea and vomiting with doses > 200 μg.

Diagnostic performance of blue laser imaging for early detection of gastric cancer: A systematic review and meta-analysis

BACKGROUND

Gastric cancer (GC) is associated with a significant global health burden and high mortality rates when diagnosed at later stages. The diagnosis often occurs at advanced stages when treatment options are limited and less effective. Early detection strategies are crucial to improving survival rates and outcomes for patients. Blue laser imaging (BLI) is an image-enhanced endoscopy technique that utilizes white light and narrow-band light to detect pathological changes in the mucosal architecture. This study aims at investigating the diagnostic performance of BLI for the detection of GC.

METHODS

A comprehensive search was conducted across multiple databases from inception until March 2023. Studies assessing the diagnostic efficacy of BLI for GC detection were included. The sensitivity, specificity and accuracy of BLI were calculated using pooled proportions and 95% confidence intervals (CI) with a random-effects model. Heterogeneity among the included studies was assessed using the I2 statistic.

RESULTS

Six studies were included in the pooled analysis. There were 708 patients with 380 GC lesions. Most of the lesions involved the lower two-thirds of the stomach. The pooled performance metrics of BLI for GC detection were as follows: sensitivity of 91.9% (95% CI 83.3-96.3%; I2 = 82.3%), specificity of 93.4% (95% CI 82.0-97.8%; I2 = 87.9%) and accuracy of 95.4% (95% CI 72.6-99.8%; I2 = 73.6%).

CONCLUSION

BLI demonstrates high diagnostic efficacy for the detection of GC. BLI can be a valuable tool in clinical practice. However, large-scale, randomized controlled studies are needed to further establish the role of BLI in routine clinical practice for GC detection.

Systematic Review and Meta-Analysis of Randomized Controlled Trials (RCTs) Revealing the Future of Airway Management: Video Laryngoscopy vs. Macintosh Laryngoscopy for Enhanced Clinical Outcomes

Since the 1940s, Macintosh laryngoscopy (Mac laryngoscopy) has been the gold standard for tracheal intubation, offering visualization of the glottis entrance. However, recent years have witnessed the emergence of various video laryngoscopy (VL) techniques. This systematic review and meta-analysis aims to assess the clinical outcomes of VL versus Mac laryngoscopy in an elective setting. We comprehensively searched five medical databases - PubMed, EMBASE, Medline, Cochrane Library, and Web of Science. All the databases were last searched in January 2023. We only included studies with full texts comparing VL to Mac laryngoscopy clinical outcomes. Studies were excluded if they were non-full text or non-randomized controlled trials (RCTs) and did not compare VL to Mac laryngoscopy. We extracted data comprising author names, publication year, key study outcomes (first-attempt intubation success rate, Cormack and Lehane grade, hypoxia incidence, and glottis view quality), video laryngoscope types, and sample sizes of both VL and Mac laryngoscopy groups. The Cochrane risk of bias tool was used to assess the risk of bias in the included studies. Statistical analysis was performed using Review Manager (RevMan, version 5.4; Cochrane Collaboration, London, UK), presenting results as odds ratio (OR) and risk ratios (RR) at a 95% confidence interval (CI). This facilitated the identification of relevant and appropriate studies of our analysis. The search produced 19 studies that were included in this review. The evaluated sample size ranges from 40 to 802, with 3,238 participants. The rate of success at the first attempt in the use of VL was 1,558/1,890 (82.43%), while the success rate for Mac laryngoscopy was 982/1,348 (72.85%; OR: 1.98 (1.25, 3.12)) at a 95% confidence interval. Pooled analysis indicated no significant difference for hypoxia concerning the type of device used RR (random effects: 1.02; 95% CI: 0.80-1.29). A video laryngoscope had a higher likelihood of visualizing the vocal cords categorized as category 1 in the Cormack-Lehane system of classification (RR: 2.45; 95% CI: 1.43-4.21). Additionally, considerably better glottis views were attained during VL than Mac laryngoscopy (OR: 1.77; 95% CI: 1.19-2.62). In elective tracheal intubation, VL demonstrates superior first-attempt success rates, offers improved glottis visualization, and reduces instances where the glottis cannot be viewed compared to Mac laryngoscopy.

Global anaesthesia-related cardiac arrest rates in children: a systematic review and meta-analysis

BACKGROUND

Neonates and infants have a higher perioperative risk of cardiac arrest and mortality than adults. The Human Development Index (HDI) ranges from 0 to 1, representing the lowest and highest levels of development, respectively. The relation between anaesthesia safety and country HDI has been described previously. We examined the relationship among the anaesthesia-related cardiac arrest rate (ARCAR), country HDI, and time in a mixed paediatric patient population.

METHODS

Electronic databases were searched up to July 2022 for studies reporting 24-h postoperative ARCARs in children. ARCARs (per 10,000 anaesthetic procedures) were analysed in low-HDI (HDI<0.8) vs high-HDI countries (HDI≥0.8) and over time (pre-2001 vs 2001-22). The magnitude of these associations was studied using systematic review methods with meta-regression analysis and meta-analysis.

RESULTS

We included 38 studies with 5,493,489 anaesthetic procedures and 1001 anaesthesia-related cardiac arrests. ARCARs were inversely correlated with country HDI (P<0.0001) but were not correlated with time (P=0.82). ARCARs did not change between the periods in either high-HDI or low-HDI countries (P=0.71 and P=0.62, respectively), but were higher in low-HDI countries than in high-HDI countries (9.6 vs 2.0; P<0.0001) in 2001-22. ARCARs were higher in children aged <1 yr than in those ≥1 yr in high-HDI (10.69 vs 1.48; odds ratio [OR] 8.03, 95% confidence interval [CI] 5.96-10.81; P<0.0001) and low-HDI countries (36.02 vs 2.86; OR 7.32, 95% CI 3.48-15.39; P<0.0001) in 2001-22.

CONCLUSIONS

The high and alarming anaesthesia-related cardiac arrest rates among children younger than 1 yr of age in high-HDI and low-HDI countries, respectively, reflect an ongoing challenge for anaesthesiologists.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42021229919.

The postoperative analgesic efficacy of liposomal bupivacaine versus long-acting local anaesthetics for peripheral nerve and field blocks: A systematic review and meta-analysis, with trial sequential analysis

BACKGROUND

Liposomal bupivacaine is claimed by the manufacturer to provide analgesia for up to 72 h postoperatively.

OBJECTIVES

To compare the postoperative analgesic efficacy of liposomal bupivacaine versus long-acting local anaesthetics for peripheral nerve or field blocks.

DESIGN

A systematic review and meta-analysis with trial sequential analysis.

DATA SOURCES

MEDLINE, Embase and Web of Science, among others, up to June 2022.

ELIGIBILITY CRITERIA

We retrieved randomised controlled trials comparing liposomal bupivacaine versus bupivacaine, levobupivacaine or ropivacaine for peripheral nerve and field blocks after all types of surgery. Our primary endpoint was rest pain score (analogue scale 0 to 10) at 24 h. Secondary endpoints included rest pain score at 48 and 72 h, and morphine consumption at 24, 48 and 72 h.

RESULTS

Twenty-seven trials including 2122 patients were identified. Rest pain scores at 24 h were significantly reduced by liposomal bupivacaine with a mean difference (95% CI) of -0.9 (-1.4 to -0.4), I2  = 87%, P  < 0.001. This reduction in pain scores persisted at 48 h and 72 h with mean differences (95% CI) of -0.7 (-1.1 to -0.3), I2  = 82%, P  = 0.001 and -0.7 (-1.1 to -0.3), I2  = 80%, P  < 0.001, respectively. There were no differences in interval morphine consumption at 24 h ( P  = 0.15), 48 h ( P  = 0.15) and 72 h ( P  = 0.07). The quality of evidence was moderate.

CONCLUSIONS

There is moderate level evidence that liposomal bupivacaine reduces rest pain scores by 0.9 out of 10 units, when compared with long-acting local anaesthetics at 24 hours after surgery, and by 0.7 up to 72 hours after surgery.

The Effect of Prophylactic Steroids on Shivering in Adults Undergoing Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Shivering is common following anesthesia and surgery. Corticosteroids (steroids) have been tried to reduce the risk of shivering, but the evidence in favor of their use is uncertain. The primary objective of this review was to evaluate the effect of steroids on the risk of perioperative (intra- and postoperative) shivering versus controls (placebo and active controls). Additional objectives were to assess the risk of severity of shivering, patient satisfaction with shivering prophylaxis, quality of recovery (QoR), and the risk of steroid-related adverse effects.

METHODS

PubMed, Embase, Cochrane Central Registry of Trials, Google Scholar, and preprint servers were searched from inception until November 30, 2022. Randomized controlled trials (RCTs) published in the English language were retrieved, provided they reported on shivering either as a primary or secondary outcome following steroid prophylaxis in adult patients undergoing surgery under spinal or general anesthesia.

RESULTS

A total of 3148 patients from 25 RCTs were included in the final analysis. The steroids used in the studies were either dexamethasone or hydrocortisone. Dexamethasone was administered intravenously or intrathecally, while hydrocortisone was administered intravenously. Prophylactic administration of steroids reduced the risk of overall shivering (risk ratio [RR], 0.65 [95% confidence interval {CI}, 0.52-0.82]; P = .0002; I2 = 77%) as well as the risk of moderate to severe shivering (RR, 0.49 [95% CI, 0.34-0.71]; P = .0002; I2 = 61%) in comparison to controls. Administration of intravenous dexamethasone (RR, 0.67 [95% CI, 0.52-0.87]; P = .002; I2 = 78%) and hydrocortisone (RR, 0.51 [95% CI, 0.32-0.80]; P = .003; I2 = 58%) were effective in shivering prophylaxis. For intrathecal dexamethasone (RR, 0.84 [95% CI, 0.34-2.08]; P = .7; I2 = 56%), the null hypothesis of no subgroup difference was not rejected ( P = .47), preventing definitive conclusions about the efficacy of this route of administration. The prediction intervals for both overall shivering risk (0.24-1.70) and risk of severity of shivering (0.23-1.0) precluded generalization of results in future studies. Meta-regression analysis was used to further explore heterogeneity. Factors like the dose and timing of administration of steroids or the type of anesthesia were not found to be significant. Patient satisfaction and QoR were higher in the dexamethasone groups versus placebo. No increased risk of adverse events of steroids was noted versus placebo or controls.

CONCLUSIONS

Prophylactic steroid administration may be beneficial in reducing the risk of perioperative shivering. However, the quality of evidence in favor of steroids is very low. Further well-designed studies are needed for establishing generalization.

The analgesic efficacy of transversus abdominis plane block vs. wound infiltration after inguinal and infra-umbilical hernia repairs: A systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Both transversus abdominis plane (TAP) block and wound infiltration with local anaesthetic have been used to relieve pain after inguinal or infra-umbilical hernia repair.

OBJECTIVES

To determine whether TAP block or local anaesthetic infiltration is the best analgesic option after inguinal or infra-umbilical hernia repair.

DESIGN

Systematic review and meta-analysis with trial sequential analysis.

DATA SOURCES

MEDLINE, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Science, up to June, 2020.

ELIGIBILITY CRITERIA

We retrieved randomised controlled trials comparing TAP block with wound infiltration after inguinal or infra-umbilical hernia repair. Primary outcome was rest pain score (analogue scale 0 to 10) at 2 postoperative hours. Secondary pain-related outcomes included rest pain score at 12 and 24 h, and intravenous morphine consumption at 2, 12 and 24 h. Other secondary outcomes sought were block-related complications such as rates of postoperative infection, haematoma, visceral injury and systemic toxicity of local anaesthetic.

RESULTS

Seven trials including 420 patients were identified. There was a significant difference in rest pain score at 2 postoperative hours in favour of TAP block compared with wound infiltration, with a mean (95% confidence interval) difference of -0.8 (-1.3 to -0.2); I2  = 85%; P   =  0.01. Most secondary pain-related outcomes were also significantly improved following TAP block. No complication was reported. The overall quality of evidence was moderate.

CONCLUSION

There is moderate level evidence that TAP block provides superior analgesia compared with wound infiltration following inguinal or infra-umbilical hernia repair.

TRIAL REGISTRY NUMBER

PROSPERO CRD42020208053.

Transversus abdominis plane block versus local anaesthetic wound infiltration for analgesia after caesarean section: A systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Transversus abdominis plane (TAP) block and local anaesthetic wound infiltration are used to relieve pain after caesarean section.

OBJECTIVES

To determine whether TAP block or local anaesthetic wound infiltration is the better analgesic option after caesarean section.

DESIGN

Systematic review and meta-analysis with trial sequential analysis.

DATA SOURCES

MEDLINE, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Science up to June 2020.

ELIGIBILITY CRITERIA

We retrieved randomised controlled trials comparing TAP block with wound infiltration after caesarean section. Primary outcome was pain score during rest (analogue scale, 0 to 10) at 2 h postoperatively, analysed according to the TAP block technique (ultrasound-guided/landmark-guided), anaesthetic strategy (spinal/general), intrathecal fentanyl (yes/no) and multimodal analgesia (yes/no). Secondary pain-related outcomes included pain scores during rest at 12 and 24 h, and total intravenous morphine consumption at 2, 12 and 24 h. We sought rates of block complications, including postoperative infection, haematoma, visceral injury and local anaesthetic systemic toxicity.

RESULTS

Seven trials, totalling 475 patients, were identified. There was no difference in pain score during rest at 2 h between groups. Subgroup analyses revealed no differences related to TAP block technique (P = 0.64), anaesthetic strategy (P = 0.53), administration of intrathecal fentanyl (P = 0.59) or presence of multimodal analgesia (P = 0.57). Pain score during rest at 12 h and intravenous morphine consumption at 2 and 12 h were identical in both groups. Data were insufficient to compare block complications. Overall quality of evidence was moderate.

CONCLUSION

There is moderate level evidence that TAP block and wound infiltration provide similar postoperative analgesia after caesarean section.

TRIAL REGISTRY NUMBER

PROSPERO CRD42020208046.

The Multivariate Effect of Ketamine on PTSD: Systematic Review and Meta-Analysis

BACKGROUND

Post-traumatic stress disorder (PTSD) is a serious stress-related disorder caused by traumatic experiences. However, identifying a key therapy that can be used for PTSD treatment remains difficult. Ketamine, a well-known dissociative anesthetic, is considered safe to be used in anesthesia, pain management, and antidepressant actions since 1970. At present, it is still controversial whether PTSD can be treated with ketamine. The authors performed a meta-analysis to determine whether the use of perioperative ketamine lowers the incidence of PTSD.

METHODS

Cochrane Central Register of Controlled Trials, Embase, PubMed, and Web of Science were searched to examine the use of ketamine for the treatment of PTSD among soldiers with combating experience. Studies were included if they were randomized placebo-controlled, case-control, and cohort studies. The primary outcome was the incidence of PTSD in the later stage of the wounded or burn soldiers. The secondary outcome was the influence of ketamine on PTSD-scale scores for early and chronic PTSD, respectively.

RESULTS

Our search yielded a total of three studies (n = 503 patients) comparing the use of ketamine (n = 349) to control (n = 154). The available evidence showed no significant difference in the incidence of PTSD between combatant soldiers on the battlefield with or without ketamine treatment (risk ratio = 0.81, 95% CI, 0.63-1.04; P = 0.10). In 65 patients from three trials, ketamine was not only ineffective in treating early PTSD but also lead to exacerbation of the disease (risk ratio = 2.45, 95% CI, 1.33-3.58; P < 0.001). However, in 91 patients from the other three trials, ketamine is effective in treating chronic PTSD (risk ratio = -3.66, 95% CI, -7.05 to -0.27; P = 0.03).

CONCLUSION

Ketamine was not effective on lower the PTSD incidence for soldiers on the battlefield, nor on the PTSD-scale scores in early PTSD patients. However, it may improve the PTSD-scale scores for chronic conditions.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021255516, PROSPERO, identifier: CRD42021255516.

Efficacy and Safety of Dexmedetomidine Premedication in Balanced Anesthesia: A Systematic Review and Meta-Analysis in Dogs

Simple Summary

Dexmedetomidine, on account of its potent sedative and analgesic properties, is commonly used in balanced anesthesia of small animal anesthesia; however, concerns regarding its cardiovascular effects prevent its full adoption into veterinary clinical practice. We conducted this meta-analysis to determine the effects of dexmedetomidine on sedation, analgesia, cardiovascular and adverse reactions in dogs compared to other premedications. The outcomes included sedation score, pain score, heart rate, systolic arterial blood pressure, mean arterial blood pressure and the incidence of adverse effects. Thirteen studies were included in this meta-analysis. The results showed that dexmedetomidine provides a satisfactory sedative and analgesic effect in balanced anesthesia of dogs. After dexmedetomidine premedication, dogs experienced lower heart rate and higher blood pressure within an acceptable range. The combinations in balanced anesthesia and routes of delivering drugs would affect heart rate, systolic arterial blood pressure, and mean arterial blood pressure of dogs. Before using dexmedetomidine, an animal’s cardiovascular status should be fully considered.

Abstract

Dexmedetomidine is commonly used in small animal anesthesia for its potent sedative and analgesic properties; however, concerns regarding its cardiovascular effects prevent its full adoption into veterinary clinical practice. This meta-analysis was to determine the effects of dexmedetomidine on sedation, analgesia, cardiovascular and adverse reactions in dogs compared to other premedications. Following the study protocol based on the Cochrane Review Methods, thirteen studies were included in this meta-analysis ultimately, involving a total of 576 dogs. Dexmedetomidine administration probably improved in sedation and analgesia in comparison to acepromazine, ketamine and lidocaine (MD: 1.96, 95% CI: [−0.08, 4.00], p = 0.06; MD: −0.95, 95% CI: [−1.52, −0.37] p = 0.001; respectively). Hemodynamic outcomes showed that dogs probably experienced lower heart rate and higher systolic arterial blood pressure and mean arterial blood pressure with dexmedetomidine at 30 min after premedication (MD: −13.25, 95% CI: [−19.67, −6.81], p < 0.0001; MD: 7.78, 95% CI: [1.83, 13.74], p = 0.01; MD: 8.32, 95% CI: [3.95, 12.70], p = 0.0002; respectively). The incidence of adverse effects was comparable between dexmedetomidine and other premedications (RR = 0.86, 95% CI [0.58, 1.29], p = 0.47). In summary, dexmedetomidine provides satisfactory sedative and analgesic effects, and its safety is proved despite its significant hemodynamic effects as part of balanced anesthesia of dogs.

The effect of perioperative dexmedetomidine on postoperative bowel function recovery in adult patients receiving general anaesthesia: a systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Dexmedetomidine has opioid sparing actions but its effect on bowel recovery is controversial. Primary aim of this review was to evaluate the effect of perioperative dexmedetomidine on postoperative bowel recovery. Secondary aim was to evaluate the effect of dexmedetomidine on hospital discharge.

EVIDENCE ACQUISITION

Randomised controlled trials in English language reporting any or all of the following parameters of bowel recovery; time to first bowel sounds, first flatus, first faeces, or time to oral diet were included.

EVIDENCE SYNTHESIS

Twelve hundred and thirty-five patients from 13 studies were analysed. There were insufficient studies evaluating bowel sounds. Perioperative dexmedetomidine usage significantly reduced the time to first flatus [MD -5.61 hours (95% CI -8.61 to -2.60); P = 0.0003; I2 = 95%], first faeces [MD -12.70 hours (95% CI -19.11 to -6.29); P = 0.0001; I2 = 76%] and the composite outcome of bowel recovery (flatus, faeces, oral diet) [MD -7.44 hours (95% CI -10.31 to -4.57); P < 0.00001; I2 = 96%]. No difference was seen in the time to oral diet [MD -6.29 hours (95% CI -13.48 to 0.91); P = 0.09; I2 = 88%] or hospital discharge [MD -0.47 days (95% CI -1.27 to 0.33); P = 0.25; I2 = 86%].

CONCLUSIONS

Perioperative dexmedetomidine usage significantly shortens the time to first flatus, faeces and composite bowel recovery but does not result in a shorter time to oral diet or earlier hospital discharge in adult patients receiving general anaesthesia. Strength of evidence is however very low for the effect of dexmedetomidine on bowel recovery.

Efficacy and safety of intrathecal morphine for analgesia after lower joint arthroplasty: a systematic review and meta-analysis with meta-regression and trial sequential analysis

Widespread adoption of intrathecal morphine into clinical practice is hampered by concerns about its potential side‐effects. We undertook a systematic review, meta‐analysis and trial sequential analysis with the primary objective of determining the efficacy and safety of intrathecal morphine. Our secondary objective was to determine the dose associated with greatest efficacy and safety. We also assessed the impact of intrathecal morphine on respiratory depression. We systematically searched the literature for trials comparing intrathecal morphine with a control group in patients undergoing hip or knee arthroplasty under spinal anaesthesia. Our primary efficacy outcome was rest pain score (0–10) at 8–12 hours; our primary safety outcome was the rate of postoperative nausea and vomiting within 24 hours. Twenty‐nine trials including 1814 patients were identified. Rest pain score at 8–12 hours was significantly reduced in the intrathecal morphine group, with a mean difference (95%CI) of −1.7 (−2.0 to −1.3), p < 0.0001 (19 trials; 1420 patients; high‐quality evidence), without sub‐group differences between doses (p = 0.35). Intrathecal morphine increased postoperative nausea and vomiting, with a risk ratio (95%CI) of 1.4 (1.3–1.6), p < 0.0001 (24 trials; 1603 patients; high‐quality evidence). However, a sub‐group analysis by dose revealed that rates of postoperative nausea and vomiting within 24 hours were similar between groups at a dose of 100 µg, while the risk significantly increased with larger doses (p value for sub‐group difference = 0.02). Patients receiving intrathecal morphine were no more likely to have respiratory depression, the risk ratio (95%CI) being 0.9 (0.5–1.7), p = 0.78 (16 trials; 1173 patients; high‐quality evidence). In conclusion, there is good evidence that intrathecal morphine provides effective analgesia after lower limb arthroplasty, without an increased risk of respiratory depression, but at the expense of an increased rate of postoperative nausea and vomiting. A dose of 100 µg is a ‘ceiling’ dose for analgesia and a threshold dose for increased rate of postoperative nausea and vomiting.

Transversus abdominis plane block versus local anesthetic wound infiltration for optimal analgesia after laparoscopic cholecystectomy: A systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Both transversus abdominis plane (TAP) block and local anesthetic wound infiltration have been used to relieve pain after laparoscopic cholecystectomy. We undertook this systematic review and meta-analysis with trial sequential analysis to determine the best analgesic technique.

METHODS

We systematically searched the literature for trials comparing TAP block with wound infiltration after laparoscopic cholecystectomy. The primary outcome was pain score during rest (analogue scale, 0-10) at 2 postoperative hours. Secondary pain-related outcomes included pain scores during rest at 12 and 24 h, pain scores during movement and intravenous morphine consumption at 2, 12 and 24 h, and postoperative nausea and vomiting. Other secondary outcomes sought were block-related complications such as rates of postoperative infection, hematoma, visceral injury and local anesthetic systemic toxicity.

RESULTS

Ten trials including 668 patients were identified. There was a significant difference in pain score during rest at 2 postoperative hours in favour of TAP block when compared with wound infiltration (mean difference [95%CI]: -0.7 [-1.2, -0.2]; I2 = 71%; p = 0.008). Pain scores during rest at 12 and 24 h and pain scores during movement at 24 h were also significantly lower with TAP block than wound infiltration. Postoperative morphine consumption and the incidence of postoperative nausea and vomiting were significantly lower in patients who received a TAP block. Data were insufficient to compare block-related complications. The overall quality of evidence was moderate-to-high.

CONCLUSIONS

There is moderate-to-high level evidence that the TAP block provides superior analgesia when compared with wound infiltration in patients undergoing laparoscopic cholecystectomy. Trial registry number: PROSPERO CRD42020208057.

Comparative effectiveness of pharmacological interventions to prevent postoperative delirium: a network meta-analysis

Many pharmacologic agents were investigated for the effect to prevent delirium. We aimed to comprehensively compare the effect of the pharmacological interventions to prevent postoperative delirium. A Bayesian network meta-analysis of randomized trials was performed using random effects model. PubMed, the Cochrane Central Register of Controlled Trials, and Embase were searched on 20 January 2021. Randomized trials comparing the effect of a drug to prevent postoperative delirium with another drug or placebo in adult patients undergoing any kind of surgery were included. Primary outcome was the postoperative incidence of delirium. Eighty-six trials with 26,992 participants were included. Dexmedetomidine, haloperidol, and atypical antipsychotics significantly decreased the incidence of delirium than placebo [dexmedetomidine: odds ratio 0.51, 95% credible interval (CrI) 0.40-0.66, moderate quality of evidence (QOE); haloperidol: odds ratio 0.59, 95% CrI 0.37-0.95, moderate QOE; atypical antipsychotics: odds ratio 0.27, 95% CrI 0.14-0.51, moderate QOE]. Dexmedetomidine and atypical antipsychotics had the highest-ranking probabilities to be the best. However, significant heterogeneity regarding diagnostic time window as well as small study effects precludes firm conclusion.

The analgesic efficacy of iPACK after knee surgery: A systematic review and meta-analysis with trial sequential analysis

STUDY OBJECTIVE

The novel infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) has been described to relieve posterior knee pain after knee surgery. The study objective is to determine whether iPACK provides analgesia after knee surgery when compared with a control group.

DESIGN

Systematic review, meta-analysis and trial sequential analysis.

SETTING

Operating room, postoperative recovery area and ward, up to 24 postoperative hours.

PATIENTS

Patients scheduled for knee surgery under general or spinal anaesthesia.

INTERVENTIONS

We searched five electronic databases for randomized controlled trials comparing iPACK with a control group.

MEASUREMENTS

The primary outcome was rest pain score scores on a visual analogue scale (VAS) of 0-10 at 12 h postoperatively, analysed according to the nature of surgery (total knee arthroplasty vs. anterior cruciate ligament reconstruction) and the use of multimodal analgesia. Secondary outcomes included rest and dynamic pain scores, intravenous morphine-equivalent consumption at 2 h and 24 h, and functional outcomes including ambulation distance and range of motion at discharge.

MAIN RESULTS

Six trials involving 687 patients were included, all of which received total knee arthroplasty only. When compared with a control group, iPACK significantly reduced rest pain scores at 12 h, with a mean difference (95% CI) of -1.0 (-1.5 to -0.5), I² = 93%, p = 0.0003, without subgroup differences for postoperative multimodal analgesia (p = 0.15). Secondary pain outcomes were inconsistently improved with iPACK. Functional outcomes were either similar between groups or had clinically unimportant differences. The overall quality of evidence was moderate.

CONCLUSIONS

There is moderate level evidence that iPACK might provide analgesia for posterior pain after total knee arthroplasty when compared with a control group at 12 h, but was not associated with any other meaningful benefits. Based on these results, there is currently limited evidence supporting the use of iPACK as a complement to adductor canal block for analgesia after total knee arthroplasty.

The effect of intravenous magnesium on postoperative morphine consumption in noncardiac surgery: A systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Several studies suggest that systemic magnesium reduces postoperative opioid consumption and the intensity of pain, but others report conflicting results. The efficacy and safety profile of intravenous magnesium in noncardiac surgery remain uncertain.

OBJECTIVES

The aim of this review was to investigate the effect of intravenous magnesium on the consumption of postoperative morphine in the first 24 h in adults undergoing noncardiac surgery.

DESIGN

Systematic review and meta-analysis with trial sequential analysis.

DATA SOURCES

MEDLINE, EMBASE, CENTRAL from their inception until January 2019.

ELIGIBILITY CRITERIA

All randomised clinical trials comparing intravenous magnesium versus placebo in noncardiac surgery were systematically searched in the databases. Observational studies, case reports, case series and nonsystematic reviews were excluded.

RESULTS

Fifty-one trials (n=3311) were included for quantitative meta-analysis. In comparison with placebo, postoperative morphine consumption at 24-h was significantly reduced in the magnesium group, with a mean difference [95% confidence interval (CI)] of -5.6 mg (-7.54 to -3.66, P < 0.001, I = 92%, level of evidence low). The trial sequential analysis for the effect of magnesium on postoperative morphine consumption was conclusive. Patients who received magnesium had a longer time to the first analgesia request [143 (103 to 183) min, P < 0.001, I = 99%, level of evidence low] and a lower incidence of shivering [0.26 (0.15 to 0.44), P < 0.001, I = 35%, level of evidence very low]. However, no significance differences were demonstrated in postoperative pain scores in the first 24 h (mean difference, 95% CI) -0.30 (-0.69 to 0.09, P = 0.13, I = 91%, level of evidence low), bradycardia (odds ratio, 95% CI) 1.13 (0.43 to 2.98, P = 0.80, I = 35%, level of evidence very low) and postoperative nausea and vomiting (odds ratio, 95% CI) 0.90 (0.67 to 1.22, P = 0.49, I = 25%, level of evidence moderate).

CONCLUSION

The current meta-analysis demonstrates that the use of intravenous magnesium as part of multimodal analgesia may reduce morphine consumption in the first 24 h after surgery and delay the time to the first request for analgesia in patients undergoing noncardiac surgery. However, the included studies were of low-quality with substantial heterogeneity.

TRIAL REGISTRATION

CRD42018086846.

Colloid preloading versus crystalloid preloading to prevent hypotension after spinal anesthesia for cesarean delivery: A protocol for systematic review and meta-analysis

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anesthesia for cesarean delivery, and intravenous fluid preloading is a preventive measure. We aimed to assess the efficacy of colloids versus crystalloids for preloading to reduce the incidence of spinal anesthesia-induced hypotension and vasopressor requirement in healthy parturients during elective cesarean delivery.

METHODS

We searched the Cochrane Library, MEDLINE and EMBASE to identify all studies published to June, 2019, through OVID and PubMed. We included randomized controlled trials, comparing colloid preloading with crystalloid preloading in women having spinal anesthesia for cesarean delivery. Primary outcomes were the incidence of hypotension and vasopressor requirement. Secondary outcomes included nausea and/or vomiting, neonatal Apgar score, neonatal umbilical blood pH. We used standardized mean differences for expressing continuous outcomes and risk ratios for dichotomous outcomes. Random-effect model was performed to estimate the pooled risk ratios and standardized mean differences.

RESULTS

Thirty-three randomized controlled trials contributed data for this meta-analysis. Fewer women experienced hypotension in the colloid group compared with the crystalloid group (risk ratio: 0.72, 95% confidence interval: 0.63-0.82; 2566 women, 32 studies; P < .00001). The total ephedrine dose required was significantly lower with colloid preloading (standardized mean difference: -0.37, 95% CI: -0.64 to -0.09; 1472 women, 19 studies; P = .009). Colloid preloading was also associated with fewer phenylephrine requirement compared with crystalloid preloading (standardized mean difference: -0.54, 95% CI: -0.82 to -0.25; 169 women; P = .0002). The incidence of nausea and/or vomiting was significantly reduced with colloid preloading (risk ratio: 0.72, 95% CI: 0.55-0.95; 1601 women, 20 studies; P = .02). However, the incidence of 1-minute Apgar score < 7, umbilical artery pH < 7.2 and umbilical vein pH < 7.2 were not statistically different between groups.

CONCLUSIONS

Colloid preloading is superior to crystalloid preloading in reducing the incidence of hypotension induced by spinal anesthesia and vasopressor requirement in the healthy parturients undergoing elective cesarean delivery.The PROSPERO registration number: CRD42018096402.

A Systematic Review and Meta-Analysis of Microvascular Stacked and Conjoined-Flap Breast Reconstruction

BACKGROUND

 Stacked and conjoined (SC) flaps are a useful means of increasing flap volume in autologous breast reconstruction. The majority of studies, however, have been limited to smaller, single-center series.

METHODS

 A systematic literature review was performed to identify outcomes-based studies on microvascular SC-flap breast reconstruction. Pooled rates of flap and operative characteristics were analyzed. Meta-analytic effect size estimates were calculated for reconstructive complication rates and outcomes of studies comparing SC flaps to non-SC flaps. Meta-regression analysis identified risk factors for flap complications.

RESULTS

 Twenty-six studies were included for analysis (21 case series, five retrospective cohort studies) for a total of 869 patients, 1,003 breasts, and 2006 flaps. The majority of flaps were harvested from the bilateral abdomen (78%, 782 breasts) followed by combined abdomen-thigh stacked flaps (22.2%, 128 breasts). About 51.1% of flaps were anastomosed to anterograde/retrograde internal mammary vessels (230 breasts) and 41.8% used internal mammary/intraflap anastomoses (188 breasts). Meta-analysis revealed a rate of any flap complication of 2.3% (95% confidence interval: 1.4-3.3%), Q-statistic value p = 0.012 (I ² = 43.3%). SC flaps had a decreased risk of fat necrosis compared with non-SC flaps (odds ratio = 0.126, p < 0.0001, I ² = 0.00%), though rates of any flap and donor-site complication were similar. Age, body mass index, flap weight, and flap donor site and recipient vessels were not associated with increased risk of any flap complication.

CONCLUSION

 A global appraisal of the current evidence demonstrated the safety of SC-flap breast reconstruction with low complication rates, regardless of donor site, and lower rates of fat necrosis compared with non-SC flaps.

Association between intra-operative cardiac arrest and country Human Development Index status: a systematic review with meta-regression analysis and meta-analysis of observational studies. Anaesthesia 2021;76:1259-1273. [PMID: 33512708 DOI: 10.1111/anae.15374]

Intra-operative cardiac arrests differ from most in-hospital cardiac arrests because they reflect not only the patient's condition but also the quality of surgery and anaesthesia care provided. We assessed the relationship between intra-operative cardiac arrest rates and country Human Development Index (HDI), and the changes occurring in these rates over time. We searched PubMed, EMBASE, Scopus, LILACS, Web of Science, CINAHL and SciELO from inception to 29 January 2020. For the global population, rates of intra-operative cardiac arrest and baseline ASA physical status were extracted. Intra-operative cardiac arrest rates were analysed by time, country HDI status and ASA physical status using meta-regression analysis. Proportional meta-analysis was performed to compare intra-operative cardiac arrest rates and ASA physical status in low- vs. high-HDI countries and in two time periods. Eighty-two studies from 25 countries with more than 29 million anaesthetic procedures were included. Intra-operative cardiac arrest rates were inversely correlated with country HDI (p = 0.0001); they decreased over time only in high-HDI countries (p = 0.040) and increased with increasing ASA physical status (p < 0.0001). Baseline ASA physical status did not change in high-HDI countries (p = 0.106), while it decreased over time in low-HDI countries (p = 0.040). In high-HDI countries, intra-operative cardiac arrest rates (per 10,000 anaesthetic procedures) decreased from 9.59 (95%CI 6.59-13.16) pre-1990 to 5.17 (95%CI 4.42-5.97) in 1990-2020 (p = 0.013). During the same time periods, no improvement was observed in the intra-operative cardiac arrest rates in low-HDI countries (p = 0.498). Odds ratios of intra-operative cardiac arrest rates in ASA 3-5 patients were 8.48 (95%CI 1.67-42.99) times higher in low-HDI countries than in high-HDI countries (p = 0.0098). Intra-operative cardiac arrest rates are related to country-HDI and decreased over time only in high-HDI countries. The widening gap in these rates between low- and high-HDI countries needs to be addressed globally.

Perioperative mortality in older patients: a systematic review with a meta-regression analysis and meta-analysis of observational studies

STUDY OBJECTIVE

Older patients have a higher probability of developing major complications during the perioperative period than other adult patients. Perioperative mortality depends on not only on a patient condition but also on the quality of perioperative care provided. We tested the hypothesis that the perioperative mortality rate among older patients has decreased over time and is related to a country's Human Development Index (HDI) status.

DESIGN

A systematic review with a meta-regression and meta-analysis of observational studies that reported perioperative mortality rates in patients aged ≥60 years was performed. We searched the PubMed, EMBASE, LILACS and SciELO databases from inception to December 30, 2019.

SETTING

Mortality rates up to the seventh postoperative day were evaluated.

MEASUREMENTS

We evaluated the quality of the included studies. Perioperative mortality rates were analysed by time, country HDI status and baseline American Society of Anesthesiologists (ASA) physical status using meta-regression. Perioperative mortality and ASA status were analysed in low- and high-HDI countries during two time periods using proportion meta-analysis.

MAIN RESULTS

We included 25 studies, which reported 4,412,100 anaesthesia procedures and 3568 perioperative deaths from 12 countries. Perioperative mortality rates in high-HDI countries decreased over time (P = 0.042). When comparing pre-1990 to 1990-2019, in high-HDI countries, the perioperative mortality rates per 10,000 anaesthesia procedures decreased 7.8-fold from 100.85 (95% CI 43.36 to 181.72) in pre-1990 to 12.98 (95% CI 6.47 to 21.70) in 1990-2019 (P < 0.0001). There were no studies from low-HDI countries pre-1990. In the period from 1990 to 2019, perioperative mortality rates did not differ between low- and high-HDI countries (P = 0.395) but the limited number of patients in low-HDI countries impaired the result. Perioperative mortality rates increased with increasing ASA status (P < 0.0001). There were more ASA III-V patients in high-HDI countries than in low-HDI countries (P < 0.0001), and the perioperative mortality rate increased 24-fold in ASA III-V patients compared with ASA I-II patients (P < 0.0001).

CONCLUSION

The perioperative mortality rates in older patients have declined over the past 60 years in high-DHI countries, highlighting that perioperative safety in this population is increasing in these countries. Since data prior to 1990 were lacking in low-HDI countries, the evolution of their mortality rates could not be analysed. The perioperative mortality rate was similar in low- and high-HDI countries in the post-1990 period, but the low number of patients in the low-HDI countries does not allow a definitive conclusion.

Perioperative and anesthesia-related cardiac arrest and mortality rates in Brazil: A systematic review and proportion meta-analysis

INTRODUCTION

Studies have shown that both perioperative and anesthesia-related cardiac arrest (CA) and mortality rates are much higher in developing countries than in developed countries. This review aimed to compare the rates of perioperative and anesthesia-related CA and mortality during 2 time periods in Brazil.

METHODS

A systematic review with meta-analysis of full-text Brazilian observational studies was conducted by searching the Medline, EMBASE, LILACS and SciELO databases up to January 29, 2020. The primary outcomes were perioperative CA and mortality rates and the secondary outcomes included anesthesia-related CA and mortality events rates up to 48 postoperative hours.

RESULTS

Eleven studies including 719,273 anesthetic procedures, 962 perioperative CAs, 134 anesthesia-related CAs, 1,239 perioperative deaths and 29 anesthesia-related deaths were included. The event rates were evaluated in 2 time periods: pre-1990 and 1990-2020. Perioperative CA rates (per 10,000 anesthetics) decreased from 39.87 (95% confidence interval [CI]: 34.60-45.50) before 1990 to 17.61 (95% CI: 9.21-28.68) in 1990-2020 (P < 0.0001), while the perioperative mortality rate did not alter (from 19.25 [95% CI: 15.64-23.24] pre-1990 to 25.40 [95% CI: 13.01-41.86] in 1990-2020; P = 0.1984). Simultaneously, the anesthesia-related CA rate decreased from 14.39 (95% CI: 11.29-17.86) to 3.90 (95% CI: 2.93-5.01; P < 0.0001), while there was no significant difference in the anesthesia-related mortality rate (from 1.75 [95% CI: 0.76-3.11] to 0.67 [95% CI: 0.09-1.66; P = 0.5404).

CONCLUSIONS

This review demonstrates an important reduction in the perioperative CA rate over time in Brazil, with a large and consistent decrease in the anesthesia-related CA rate; however, there were no significant differences in perioperative and anesthesia-related mortality rates between the assessed time periods.

Intrathecal hydrophilic opioids for abdominal surgery: a meta-analysis, meta-regression, and trial sequential analysis

Background

Intrathecal hydrophilic opioids decrease systemic opioid consumption after abdominal surgery and potentially facilitate enhanced recovery. A meta-analysis is needed to quantify associated risks and benefits.

Methods

A systematic search was performed to find RCTs investigating intrathecal hydrophilic opioids in abdominal surgery. Caesarean section and continuous regional or neuraxial techniques were excluded. Several subgroup analyses were prespecified. A conventional meta-analysis, meta-regression, trial sequential analysis, and provision of GRADE scores were planned.

Results

The search yielded 40 trials consisting of 2500 patients. A difference was detected in ‘i.v. morphine consumption’ at Day 1 {mean difference [MD] −18.4 mg, (95% confidence interval [CI]: −22.3 to −14.4)} and Day 2 (MD −25.5 mg [95% CI: −30.2 to −20.8]), pain scores at Day 1 in rest (MD −0.9 [95% CI: −1.1 to −0.7]) and during movement (MD −1.2 [95% CI: −1.6 to −0.8]), length of stay (MD −0.2 days [95% CI: −0.4 to −0.1]) and pruritus (relative risk 4.3 [95% CI: 2.5–7.5]) but not in nausea or sedation. A difference was detected for respiratory depression (odds ratio 5.5 [95% CI: 2.1–14.2]) but not when two small outlying studies were excluded (odds ratio 1.4 [95% CI: 0.4–5.2]). The level of evidence was graded as high for morphine consumption, in part because the required information size was reached.

Conclusions

This study showed important opioid-sparing effects of intrathecal hydrophilic opioids. Our data suggest a dose-dependent relationship between the risk of respiratory depression and the dose of intrathecal opioids. Excluding two high-dose studies, intrathecal opioids have a comparable incidence of respiratory depression as the control group.

Clinical trial registration

PROSPERO-registry: CRD42018090682.

The Effect of Prehospital Epinephrine in Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

INTRODUCTION

Epinephrine has been recommended for out-of-hospital cardiac arrest (OHCA) resuscitation for nearly one century, but its efficacy and safety remain unclear in the literature. The primary aim of this review was to determine whether epinephrine increases the return of spontaneous circulation in OHCA patients.

METHODS

A systematic review and meta-analysis were conducted using the following databases: MEDLINE, EMBASE, and CENTRAL, from their inception until October 2018. All the randomized controlled trials (RCTs) were included. Observational studies, case reports, case series, and non-systematic reviews were excluded.

RESULTS

Two trials including 8,548 patients were eligible for inclusion in the data synthesis. In patients who received epinephrine during OHCA, the incidence of return of spontaneous circulation was increased, with an odds ratio (95%CI) of 4.25 (3.79-4.75), P <.001, high-quality of evidence. The number of patients transported to hospital was increased in patients who had prehospital epinephrine, with an odds ratio (95%CI) of 2.31 (2.11-2.53), P <.001, high-quality of evidence. The prehospital use of epinephrine was associated with an increased survival to hospital discharge, the odds ratio (95%CI) being 1.43 (1.10-1.87), P = .008, moderate-quality of evidence. No significant effect was noted on the favorable neurologic state of patient at hospital discharge, with an odds ratio (95%CI) of 1.21 (0.90-1.64), P = .21, moderate-quality of evidence.

CONCLUSIONS

This meta-analysis suggests that the prehospital use of epinephrine increases return of spontaneous circulation, transport of patients to hospital, and survival to hospital discharge for OHCA. However, no significant effects on favorable neurologic function at hospital discharge were demonstrated. The general quality of evidence ranged from moderate to high.

Videolaryngoscopy vs. Macintosh laryngoscopy for double-lumen tube intubation in thoracic surgery: a systematic review and meta-analysis

Double-lumen intubation is more difficult than single-lumen tracheal intubation. Videolaryngoscopes have many advantages in airway management. However, the advantages of videolaryngoscopy for intubation with a double-lumen tube remain controversial compared with traditional Macintosh laryngoscopy. In this study, we searched MEDLINE, Embase, Cochrane Library and the Web of Science for randomised controlled trials comparing videolaryngoscopy with Macintosh laryngoscopy for double-lumen tube intubation. We found that videolaryngoscopy provided a higher success rate at first attempt for double-lumen tube intubation, with an odds ratio (95%CI) of 2.77 (1.92-4.00) (12 studies, 1215 patients, moderate-quality evidence, p < 0.00001), as well as a lower incidence of oral, mucosal or dental injuries during double-lumen tube intubation, odds ratio (95%CI) 0.36 (0.15-0.85) (11 studies, 1145 patients, low-quality evidence, p = 0.02), and for postoperative sore throat, odds ratio (95%CI) 0.54 (0.36-0.81) (7 studies, 561 patients, moderate-quality evidence, p = 0.003), compared with Macintosh laryngoscopy. There were no significant differences in intubation time, with a standardised mean difference (95%CI) of -0.10 (-0.62 to 0.42) (14 studies, 1310 patients, very low-quality evidence, p = 0.71); and the incidence of postoperative voice change, odds ratio (95%CI) 0.53 (0.21-1.31) (7 studies, 535 patients, low-quality evidence, p = 0.17). Videolaryngoscopy led to a higher incidence of malpositioned double-lumen tube, with an odds ratio (95%CI) of 2.23 (1.10-4.52) (six studies, 487 patients, moderate-quality evidence, p = 0.03).

Combined spinal-epidural vs. spinal anaesthesia for caesarean section: meta-analysis and trial-sequential analysis

Combined spinal-epidural and single-shot spinal anaesthesia are both used for caesarean section. It has been claimed in individual trials that combined spinal-epidural is associated with higher sensory spread and greater cardiovascular stability. We set out to gather all available evidence. We performed: a systematic literature search to identify randomised controlled trials comparing combined spinal-epidural with spinal anaesthesia for caesarean section: conventional meta-analysis; trial-sequential analysis; and assessment of trial quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Fifteen trials with high heterogeneity, including 1015 patients, were analysed. There was no significant difference between combined spinal-epidural and spinal anaesthesia for our primary outcomes maximum sensory height and vasopressor use (mg ephedrine equivalents). However, trial-sequential analysis suggested insufficient data and the GRADE scores showed 'very low' quality of evidence for these outcomes. The secondary outcomes hypotension, time for sensory block to recede to the level of T10, and the combined outcome of nausea and vomiting, did not differ significantly between the interventions. The block times were statistically significantly longer for combined spinal-epidural in individual trials, but only one trial showed a clinically meaningful difference (11 min). Based on this analysis, and taking into consideration all comparisons irrespective of whether drugs had been applied via the epidural route, there is not enough evidence to postulate any advantage compared with the spinal technique. Future analyses and studies need to examine the potential advantages of the combined spinal-epidural technique by using the epidural route intra- and/or postoperatively.