Can systematic reviews with sparse data be trusted?

TACE plus tyrosine kinase inhibitors and immune checkpoint inhibitors versus TACE plus tyrosine kinase inhibitors for the treatment of patients with hepatocellular carcinoma: a meta-analysis and trial sequential analysis

BACKGROUND

We conducted a meta-analysis and trial sequential analysis (TSA) to compare the therapeutic efficacy and adverse events (AEs) between the following treatment strategies for patients with hepatocellular carcinoma (HCC): TACE plus tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs) (TACE + T + I) versus TACE plus TKIs (TACE + T).

METHODS

We systematically searched PubMed, the Web of Science, the Cochrane Library, and Embase for studies comparing TACE + T + I and TACE + T for the treatment of BCLC intermediate- or advanced-stage HCC. The objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and AEs were included as outcomes. We used a fixed- or random-effects model based on the results of a heterogeneity evaluation and performed a meta-analysis using Review Manager 5.3 and Stata 16.0. We then carried out the TSA.

RESULTS

Five studies examining a total of 425 patients were included in this study. Our meta-analysis revealed that, compared to TACE + T, TACE + T + I significantly improved the ORR (risk ratio [RR] = 1.53, 95% confidence interval [CI] = 1.27-1.85, p < 0.01) and extended both the median PFS (mean difference [MD] = 4.51 months, 95% CI = 2.16-6.87, p < 0.01) and median OS (MD = 5.75 months, 95% CI = 4.03-7.48, p < 0.01). These results were tested to be true by the TSA without requiring a larger information size. Among AEs, hypertension tended to occur more often in patients treated with TACE + T + I than in those treated with TACE + T (RR = 1.58, 95% CI = 1.05-2.40, p < 0.05). However, the TSA suggested that additional cases are necessary to confirm this difference. Regarding the other AEs, no significant differences were detected between the two groups.

CONCLUSION

TACE + T + I showed better effects on the ORR, PFS, and OS than TACE + T as a treatment for BCLC stages B and C HCC, without an obvious increase in the AEs. Based on these findings, well-designed, large RCTs are suggested.

Subcutaneous fast-acting insulin analogues, alone or in combination with long-acting insulin, versus intravenous regular insulin infusion in patients with diabetic ketoacidosis: protocol for an updated systematic review and meta-analysis of randomised trials

INTRODUCTION

Diabetic ketoacidosis (DKA) is traditionally managed using intravenous regular insulin infusion (RII) in intensive care unit (ICU)/high dependency unit (HDU). Subcutaneous fast-acting insulin analogues (FAIAs) may help to manage DKA outside ICU/HDU. Furthermore, combining subcutaneous long-acting insulin (LAI) with subcutaneous FAIAs may accelerate ketoacidosis resolution. The latest (2016) Cochrane review was inconclusive regarding subcutaneous FAIAs versus intravenous RII in DKA. It was limited by small sample sizes, unclear risk of bias (RoB) in primary trials and did not examine subcutaneous FAIAs with subcutaneous LAI versus intravenous RII in DKA. We report the protocol for an updated meta-analysis on the safety and benefits of subcutaneous FAIAs with/without subcutaneous LAI versus intravenous RII in DKA.

METHODS AND ANALYSIS

We will search Medline, Embase, CINAHL and Cochrane Library, from inception until December 2022, without language restrictions, for randomised trials on subcutaneous FAIAs with/without subcutaneous LAI versus intravenous RII in DKA. We also search ClinicalTrials.gov, ClinicalTrialsRegister.eu and reference lists of included trials. Primary outcomes include all-cause in-hospital mortality, time to DKA resolution, in-hospital DKA recurrence and hospital readmission for DKA post-discharge. Secondary outcomes include resource utilisation and patient satisfaction. Safety outcomes include important complications of DKA and insulin. Reviewers will extract data, assess overall RoB and quality of evidence using Grading of Recommendations, Assessment, Development and Evaluation. We will assess statistical heterogeneity by visually inspecting forest plots and the I² statistic. We will synthesise data using the random-effects model. Predefined subgroup analyses are: mild versus moderate versus severe DKA; age <20 vs ≥20 years; pregnant versus non-pregnant; infective versus non-infective DKA precipitating cause; subcutaneous FAIAs alone versus subcutaneous FAIAs and subcutaneous LAI; and high versus low overall RoB. We will also perform trial sequential analysis for primary outcomes.

ETHICS AND DISSEMINATION

Ethics board approval is not required. Results will be disseminated through publication in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022369518.

Melatonin or Ramelteon for Delirium Prevention in the Intensive Care Unit: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Melatonin modulates the circadian rhythm and has been studied as a preventive measure against the development of delirium in hospitalized patients. Such an effect may be more evident in patients admitted to the ICU, but findings from the literature are conflicting. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). We assessed whether melatonin or ramelteon (melatonin agonist) reduce delirium incidence as compared to a placebo in ICU patients. Secondary outcomes were ICU length of stay, duration of mechanical ventilation (MV) and mortality. Estimates are presented as risk ratio (RR) or mean differences (MD) with 95% confidence interval (CI). Nine RCTs were included, six of them reporting delirium incidence. Neither melatonin nor ramelteon reduced delirium incidence (RR 0.76 (0.54, 1.07), p = 0.12; I² = 64%), although a sensitivity analysis conducted adding other four studies showed a reduction in the risk of delirium (RR = 0.67 (95%CI 0.48, 0.92), p = 0.01; I² = 67). Among the secondary outcomes, we found a trend towards a reduction in the duration of MV (MD -2.80 (-6.06, 0.47), p = 0.09; I² = 94%) but no differences in ICU-LOS (MD -0.26 (95%CI -0.89, 0.37), p = 0.42; I² = 75%) and mortality (RR = 0.85 (95%CI 0.63, 1.15), p = 0.30; I² = 0%). Melatonin and ramelteon do not seem to reduce delirium incidence in ICU patients but evidence is weak. More studies are needed to confirm this finding.

Chinese Herbal Medicine for the Treatment of Children and Adolescents With Refractory Mycoplasma Pneumoniae Pneumonia: A Systematic Review and a Meta-Analysis

Objectives: Chinese herb medicine (CHM) is one of the most popular complementary and alternative therapies, which has been widely used to treat Refractory Mycoplasma Pneumoniae Pneumonia (RMPP). However, the effect and safety of CHM remain controversial. Hence, we conducted this meta-analysis to evaluate whether CHM combination therapy could bring benefits to children and adolescents with RMPP. Methods: Seven databases were used for data searching through November 11, 2020 following the PRISMA checklist generally. Review Manager 5.3, Trial sequential analysis 0.9.5.10 Beta software and Stata16.0 were applied to perform data analyses. Mean difference or risk ratio was adopted to express the results, where a 95% confidence interval (CI) was applied. Results: In general, this research enrolled 17 trials with 1,451 participants. The overall pooled results indicated that CHM was beneficial for children and adolescents with RMPP by improving the clinical efficacy rate [RR = 1.20, 95% CI (1.15, 1.25), p < 0.00001], shortening antipyretic time [MD = -2.60, 95% CI (-3.06, -2.13), p < 0.00001], cough disappearance time [MD = -2.77, 95% CI (-3.12, -2.42), p < 0.00001], lung rale disappearance time [MD = -2.65, 95% CI (-3.15, -2.15), p < 0.00001], lung X-ray infiltrates disappearance time [MD = -2.75, 95% CI (-3.33, -2.17), p < 0.00001], reducing TNF-α level [MD = -5.49, 95% CI (-7.21, -3.77), p < 0.00001]. Moreover, subgroup results suggested that removing heat-phlegm and toxicity therapy had more advantages in shortening antipyretic time, cough disappearance time, lung X-ray infiltrates disappearance time and reducing TNF-α level. Meanwhile promoting blood circulation therapy seemed to be better at relieving lung rale. However, regarding adverse events, the two groups displayed no statistical difference [RR = 0.97, 95% CI (0.60, 1.57), p = 0.91]. Conclusion: Despite of the apparently positive results in relieving clinical symptoms, physical signs and reducing inflammation, it is premature to confirm the efficacy of CHM in treating RMPP because of the limitation of quality and the number of the included studies. More large-scale, double-blind, well-designed, randomized controlled trials are needed in future research.

Trial sequential analysis: novel approach for meta-analysis

Systematic reviews and meta-analyses rank the highest in the evidence hierarchy. However, they still have the risk of spurious results because they include too few studies and participants. The use of trial sequential analysis (TSA) has increased recently, providing more information on the precision and uncertainty of meta-analysis results. This makes it a powerful tool for clinicians to assess the conclusiveness of meta-analysis. TSA provides monitoring boundaries or futility boundaries, helping clinicians prevent unnecessary trials. The use and interpretation of TSA should be based on an understanding of the principles and assumptions behind TSA, which may provide more accurate, precise, and unbiased information to clinicians, patients, and policymakers. In this article, the history, background, principles, and assumptions behind TSA are described, which would lead to its better understanding, implementation, and interpretation.

High-flow nasal cannulae for respiratory support in adult intensive care patients

BACKGROUND

High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adults experiencing acute respiratory failure, or at risk of acute respiratory failure, in the intensive care unit (ICU). This is an update of an earlier version of the review.

OBJECTIVES

To assess the effectiveness of HFNC compared to standard oxygen therapy, or non-invasive ventilation (NIV) or non-invasive positive pressure ventilation (NIPPV), for respiratory support in adults in the ICU.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, Web of Science, and the Cochrane COVID-19 Register (17 April 2020), clinical trial registers (6 April 2020) and conducted forward and backward citation searches.

SELECTION CRITERIA

We included randomized controlled studies (RCTs) with a parallel-group or cross-over design comparing HFNC use versus other types of non-invasive respiratory support (standard oxygen therapy via nasal cannulae or mask; or NIV or NIPPV which included continuous positive airway pressure and bilevel positive airway pressure) in adults admitted to the ICU.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 31 studies (22 parallel-group and nine cross-over designs) with 5136 participants; this update included 20 new studies. Twenty-one studies compared HFNC with standard oxygen therapy, and 13 compared HFNC with NIV or NIPPV; three studies included both comparisons. We found 51 ongoing studies (estimated 12,807 participants), and 19 studies awaiting classification for which we could not ascertain study eligibility information. In 18 studies, treatment was initiated after extubation. In the remaining studies, participants were not previously mechanically ventilated. HFNC versus standard oxygen therapy HFNC may lead to less treatment failure as indicated by escalation to alternative types of oxygen therapy (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.45 to 0.86; 15 studies, 3044 participants; low-certainty evidence). HFNC probably makes little or no difference in mortality when compared with standard oxygen therapy (RR 0.96, 95% CI 0.82 to 1.11; 11 studies, 2673 participants; moderate-certainty evidence). HFNC probably results in little or no difference to cases of pneumonia (RR 0.72, 95% CI 0.48 to 1.09; 4 studies, 1057 participants; moderate-certainty evidence), and we were uncertain of its effect on nasal mucosa or skin trauma (RR 3.66, 95% CI 0.43 to 31.48; 2 studies, 617 participants; very low-certainty evidence). We found low-certainty evidence that HFNC may make little or no difference to the length of ICU stay according to the type of respiratory support used (MD 0.12 days, 95% CI -0.03 to 0.27; 7 studies, 1014 participants). We are uncertain whether HFNC made any difference to the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) within 24 hours of treatment (MD 10.34 mmHg, 95% CI -17.31 to 38; 5 studies, 600 participants; very low-certainty evidence). We are uncertain whether HFNC made any difference to short-term comfort (MD 0.31, 95% CI -0.60 to 1.22; 4 studies, 662 participants, very low-certainty evidence), or to long-term comfort (MD 0.59, 95% CI -2.29 to 3.47; 2 studies, 445 participants, very low-certainty evidence). HFNC versus NIV or NIPPV We found no evidence of a difference between groups in treatment failure when HFNC were used post-extubation or without prior use of mechanical ventilation (RR 0.98, 95% CI 0.78 to 1.22; 5 studies, 1758 participants; low-certainty evidence), or in-hospital mortality (RR 0.92, 95% CI 0.64 to 1.31; 5 studies, 1758 participants; low-certainty evidence). We are very uncertain about the effect of using HFNC on incidence of pneumonia (RR 0.51, 95% CI 0.17 to 1.52; 3 studies, 1750 participants; very low-certainty evidence), and HFNC may result in little or no difference to barotrauma (RR 1.15, 95% CI 0.42 to 3.14; 1 study, 830 participants; low-certainty evidence). HFNC may make little or no difference to the length of ICU stay (MD -0.72 days, 95% CI -2.85 to 1.42; 2 studies, 246 participants; low-certainty evidence). The ratio of PaO2/FiO2 may be lower up to 24 hours with HFNC use (MD -58.10 mmHg, 95% CI -71.68 to -44.51; 3 studies, 1086 participants; low-certainty evidence). We are uncertain whether HFNC improved short-term comfort when measured using comfort scores (MD 1.33, 95% CI 0.74 to 1.92; 2 studies, 258 participants) and responses to questionnaires (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 168 participants); evidence for short-term comfort was very low certainty. No studies reported on nasal mucosa or skin trauma.

AUTHORS' CONCLUSIONS

HFNC may lead to less treatment failure when compared to standard oxygen therapy, but probably makes little or no difference to treatment failure when compared to NIV or NIPPV. For most other review outcomes, we found no evidence of a difference in effect. However, the evidence was often of low or very low certainty. We found a large number of ongoing studies; including these in future updates could increase the certainty or may alter the direction of these effects.

Comparison of videolaryngoscopy and direct laryngoscopy for tracheal intubation in obstetrics: a mixed-methods systematic review and meta-analysis

PURPOSE

The incidence of difficult and failed intubation is higher in obstetrical patients than in the general population because of anatomic and physiologic changes in pregnancy. Videolaryngoscopy improves the success rate of intubation and reduces complications when compared with direct laryngoscopy in adults; however, it is not known whether this extends to obstetrical surgery. The aim of this study was to examine the efficacy, efficiency, and safety of videolaryngoscopy compared with direct laryngoscopy in obstetrics.

SOURCE

Central, CINAHL, Embase, MEDLINE and Web of Science databases were searched from inception to 27 May 2020 with no restrictions. Inclusion criteria included randomized-controlled trials (RCTs), observational studies, case series, and case reports that reported the application of videolaryngoscopy to intubate the trachea in pregnant patients having general anesthesia.

PRINCIPAL FINDINGS

Overall, four RCTs with 428 participants, nine observational studies, and 35 case reports/series with 100 participants were included. On meta-analysis of three trials, the co-primary outcomes of first-attempt success rate (risk ratio, 1.02; 95% confidence intervals [CI], 0.98 to 1.06; P = 0.29; I2 = 0%) and time to tracheal intubation (mean difference, 1.20 sec; 95% CI, -6.63 to 9.04; P = 0.76; I² = 95%) demonstrated no difference between videolaryngoscopy and direct laryngoscopy in parturients without difficult airways. Observational studies and case reports underline the role of videolaryngoscopy as a primary choice when difficulty with tracheal intubation is expected or as a rescue modality in difficult or failed intubations.

CONCLUSIONS

Evidence for the utility of videolaryngoscopy continues to evolve but supports its increased adoption in obstetrics where videolaryngoscopes should be immediately available for use as a first-line device.

TRIAL REGISTRATION

PROSPERO (CRD42020189521); registered 6 July 2020.

The use of intravenous lidocaine for postoperative pain and recovery: international consensus statement on efficacy and safety

Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk-benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre-existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high-risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri-operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg^-1 , calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg^-1 .h^-1 for no longer than 24 h is recommended, subject to review and re-assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion.

Preoperative iron treatment in anaemic patients undergoing elective total hip or knee arthroplasty: a systematic review and meta-analysis

OBJECTIVES

Preoperative anaemia is associated with increased risks of postoperative complications, blood transfusion and mortality. This meta-analysis aims to review the best available evidence on the clinical effectiveness of preoperative iron in anaemic patients undergoing elective total hip (THR) or total knee replacement (TKR).

DESIGN

Electronic databases and handsearching were used to identify randomised and non-randomised studies of interventions (NRSI) reporting perioperative blood transfusion rates for anaemic participants receiving iron before elective THR or TKR. Searches of CENTRAL, MEDLINE, Embase, PubMed and other databases were conducted on 17 April 2019 and updated on 15 July 2020. Two investigators independently reviewed studies for eligibility and evaluated risk of bias using the Cochrane risk of bias tool for randomised controlled trials (RCTs) and a modified Newcastle-Ottawa scale for NRSIs. Data extraction was performed by ABS and checked by AB. Meta-analysis used the Mantel-Haenszel method and random-effects models.

RESULTS

807 records were identified: 12 studies met the inclusion criteria, of which 10 were eligible for meta-analyses (one RCT and nine NRSIs). Five of the NRSIs were of high-quality while there were some concerns of bias in the RCT. Meta-analysis of 10 studies (n=2178 participants) showed a 39% reduction in risk of receiving a perioperative blood transfusion with iron compared with no iron (risk ratio 0.61, 95% CI 0.50 to 0.73, p<0.001, I²=0%). There was a significant reduction in the number of red blood cell units transfused with iron compared with no iron (mean difference -0.37units, 95% CI -0.47 to -0.27, p<0.001, I²=40%); six studies (n=1496). Length of stay was significantly reduced with iron, by an average of 2.08 days (95% CI -2.64 to -1.51, p<0.001, I²=40%); five studies (n=1140).

CONCLUSIONS

Preoperative iron in anaemic, elective THR or TKR patients, significantly reduces the number of patients and number of units transfused and length of stay. However, high-quality, randomised trials are lacking.

PROSPERO REGISTRATION NUMBER

CRD42019129035.

Conventional landmark palpation vs. preprocedural ultrasound for neuraxial analgesia and anaesthesia in obstetrics - a systematic review and meta-analysis with trial sequential analyses

The aim of this systematic review and meta-analysis was to examine the efficacy, time taken and the safety of neuraxial blockade performed for obstetric patients with the assistance of preprocedural ultrasound, in comparison with the landmark palpation method. The bibliographic databases Central, CINAHL, EMBASE, Global Health, MEDLINE, Scopus and Web of Science were searched from inception to 13 February 2020 for randomised controlled trials that included pregnant women having neuraxial procedures with preprocedural ultrasound as the intervention and conventional landmark palpation as the comparator. For continuous and dichotomous outcomes, respectively, we calculated the mean difference using the inverse-variance method and the risk ratio with the Mantel-Haenszel method. In all, 22 trials with 2462 patients were included. Confirmed by trial sequential analysis, preprocedural ultrasound increased the first-pass success rate by a risk ratio (95%CI) of 1.46 (1.16-1.82), p = 0.001 in 13 trials with 1253 patients. No evidence of a difference was found in the total time taken between preprocedural ultrasound and landmark palpation, with a mean difference (95%CI) of 50.1 (-13.7 to 113.94) s, p = 0.12 in eight trials with 709 patients. The quality of evidence was graded as low and very low, respectively, for these co-primary outcomes. Sub-group analysis underlined the increased benefit of preprocedural ultrasound for those in whom the neuraxial procedure was predicted to be difficult. Complications, including postpartum back pain and headache, were decreased with preprocedural ultrasound. The adoption of preprocedural ultrasound for neuraxial procedures in obstetrics is recommended and, in the opinion of the authors, should be considered as a standard of care, in view of its potential to increase efficacy and reduce complications without significant prolongation of the total time required.

Proportional assist ventilation versus pressure support ventilation for weaning from mechanical ventilation in adults: a meta-analysis and trial sequential analysis

Background

Pressure support ventilation (PSV) is the prevalent weaning method. Proportional assist ventilation (PAV) is an assisted ventilation mode, which is recently being applied to wean the patients from mechanical ventilation. Whether PAV or PSV is superior for weaning remains unclear.

Methods

Eligible randomized controlled trials published before April 2020 were retrieved from databases. We calculated the risk ratio (RR) and mean difference (MD) with 95% confidence intervals (CIs).

Results

Seven articles, involving 634 patients, met the selection criteria. Compared to PSV, PAV was associated with a significantly higher rate of weaning success (fixed-effect RR 1.16; 95% CI 1.07–1.26; I² = 0.0%; trial sequential analysis-adjusted CI 1.03–1.30), and the trial sequential monitoring boundary for benefit was crossed. Compared to PSV, PAV was associated with a lower proportion of patients requiring reintubation (RR 0.49; 95% CI 0.28–0.87; I² = 0%), a shorter ICU length of stay (MD − 1.58 (days), 95% CI − 2.68 to − 0.47; I² = 0%), and a shorter mechanical ventilation duration (MD − 40.26 (hours); 95% CI − 66.67 to − 13.84; I² = 0%). There was no significant difference between PAV and PSV with regard to mortality (RR 0.66; 95% CI 0.42–1.06; I² = 0%) or weaning duration (MD − 0.01 (hours); 95% CI − 1.30–1.28; I² = 0%).

Conclusion

The results of the meta-analysis suggest that PAV is superior to PSV in terms of weaning success, and the statistical power is confirmed using trial sequential analysis.

Graphical abstract

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.

Genetic Association between NFKBIA and NFKB1 Gene Polymorphisms and the Susceptibility to Head and Neck Cancer: A Meta-Analysis

Background

The role of the NFKB1 gene rs28362491 polymorphism and NFKBIA gene rs2233406 polymorphism in the development of head and neck cancer (HNC) remains controversial. This meta-analysis was performed to assess the relationship between the gene polymorphisms and HNC quantitatively.

Methods

PubMed, Embase, Web of Science, WanFang Data, and China National Knowledge databases were used to search for eligible articles. The relationship was evaluated by STATA 11.0.

Results

Eight eligible articles were included in our study. Nine case-control studies from the eight included articles were correlated with rs28362491 polymorphism. Four articles were related to rs2233406 polymorphism. Overall, a significant correlation was observed between the rs28362491 polymorphism and a decreased risk of HNCs (OR = 0.76, 95%CI = 0.60‐0.97 for DD vs. II; OR = 0.80, 95%CI = 0.68‐0.95 for DD vs. DI+II). In subgroup analyses, the rs28362491 polymorphism was associated with the risk of nasopharyngeal carcinoma (NC), but not with oral cancer (OC). In addition, no statistical correlation was found between the polymorphism of rs2233406 and HNCs.

Conclusion

rs28362491 polymorphism was significantly associated with the risk of HNCs, especially with NC. Additionally, our results showed that no association was discovered between rs2233406 polymorphism and HNCs.

Study-based registers reduce waste in systematic reviewing: discussion and case report

BACKGROUND

Maintained study-based registers (SBRs) have, at their core, study records linked to, potentially, multiple other records such as references, data sets, standard texts and full-text reports. Such registers can minimise and refine searching, de-duplicating, screening and acquisition of full texts. SBRs can facilitate new review titles/updates and, within seconds, inform the team about the potential workload of each task.

METHODS

We discuss the advantages/disadvantages of SBRs and report a case of how such a register was used to develop a successful grant application and deliver results-reducing considerable redundancy of effort.

RESULTS

SBRs saved time in question-setting and scoping and made rapid production of nine Cochrane systematic reviews possible.

CONCLUSION

Whilst helping prioritise and conduct systematic reviews, SBRs improve quality. Those funding information specialists for literature reviewing could reasonably stipulate the resulting SBR to be delivered for dissemination and use beyond the life of the project.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review

Difficulties with tracheal intubation commonly arise and impact patient safety. This systematic review evaluates whether videolaryngoscopes reduce intubation failure and complications compared with direct laryngoscopy in adults. We searched CENTRAL, MEDLINE, Embase and clinicaltrials.gov up to February 2015, and conducted forward and backward citation tracking. We included randomized controlled trials that compared adult patients undergoing laryngoscopy with videolaryngoscopy or Macintosh laryngoscopy. We did not primarily intend to compare individual videolaryngoscopes. Sixty-four studies (7044 participants) were included. Moderate quality evidence showed that videolaryngoscopy reduced failed intubations (Odds Ratio (OR) 0.35, 95% Confidence Interval (CI) 0.19-0.65) including in participants with anticipated difficult airways (OR 0.28, 95% CI 0.15-0.55). There was no evidence of reduction in hypoxia or mortality, but few studies reported these outcomes. Videolaryngoscopes reduced laryngeal/airway trauma (OR 0.68, 95% CI 0.48-0.96) and hoarseness (OR 0.57, 95% CI 0.36-0.88). Videolaryngoscopy increased easy laryngeal views (OR 6.77, 95% CI 4.17-10.98) and reduced difficult views (OR 0.18, 95% CI 0.13-0.27) and intubation difficulty, typically using an 'intubation difficulty score' (OR 7.13, 95% CI 3.12-16.31). Failed intubations were reduced with experienced operators (OR 0.32, 95% CI 0.13-0.75) but not with inexperienced users. We identified no difference in number of first attempts and incidence of sore throat. Heterogeneity around time for intubation data prevented meta-analysis. We found evidence of differential performance between different videolaryngoscope designs. Lack of data prevented analysis of impact of obesity or clinical location on failed intubation rates. Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a videolaryngoscope reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a videolaryngoscope affects time required for intubation.

Use of hyaluronidase as an adjunct to local anaesthetic eye blocks to reduce intraoperative pain in adults

BACKGROUND

Hyaluronidase has been used over many decades as an adjunct to local anaesthetic solution to improve the speed of onset of eye blocks and to provide better akinesia and analgesia. With the evolution of modern eye surgery techniques, fast onset and akinesia are not essential requirements anymore. The assumption that the addition of hyaluronidase to local anaesthetic injections confers better analgesia for the patient needs to be examined. There has been no recent systematic review to provide evidence that hyaluronidase actually improves analgesia.

OBJECTIVES

To ascertain if adding hyaluronidase to local anaesthetic solutions for use in ophthalmic anaesthesia in adults results in a reduction of perceived pain during the operation and to assess harms, participant and surgical satisfaction, and economic impact.

SEARCH METHODS

We carried out systematic searches in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and four other databases in June 2017. We searched the trial registers at www.ISRCTN.com, ClinicalTrials.gov and www.clinicaltrialsregister.eu for relevant trials. We imposed no language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated the effect of hyaluronidase on pain experienced by adults during intraocular surgery using a rating scale.

DATA COLLECTION AND ANALYSIS

Two review authors (HR and KA) independently extracted data and assessed methodological quality using standard procedures as expected by Cochrane.

MAIN RESULTS

We included seven trials involving 500 participants that studied the effect of hyaluronidase on intraoperative pain. Four of the seven trials with 289 participants reported the primary outcome in a dichotomous manner, and we proceeded to meta-analyse the findings which showed a moderate heterogeneity that could not be explained (I² = 41% ). The pooled risk ratio (RR) for these four trials was 0.83 with the 95% confidence interval ranging from 0.48 to 1.42. The reduction in intraoperative pain scores in the hyaluronidase group were not statistically significant. Among the three trials that reported the primary outcome in a continuous manner, the presence of missing data made it difficult to conduct a meta-analysis. To further explore the data, we imputed standard deviations for the other studies from another included RCT (Sedghipour 2012). However, this resulted in substantial heterogeneity between study estimates (I² = 76% ). The lack of reported relevant data in two of the three remaining trials made it difficult to assess the direction of effect in a clinical setting.Overall, there was no statistical difference regarding the intraoperative reduction of pain scores between the hyaluronidase and control group. All seven included trials had a low risk of bias.According to GRADE, we found the quality of evidence was low and downgraded the trials for serious risk of inconsistency and imprecision. Therefore, the results should be analysed with caution.Participant satisfaction scores were significantly higher in the hyaluronidase group in two high quality trials with 122 participants. Surgical satisfaction was also superior in two of three high quality trials involving 141 participants. According to GRADE, the quality of evidence was moderate for participant and surgical satisfaction as the trials were downgraded for imprecision due to the small sample sizes. The risk of bias in these trials was low.There was no reported harm due to the addition of hyaluronidase in any of the studies. No study reported on the cost of hyaluronidase in the context of eye surgery.

AUTHORS' CONCLUSIONS

The effects of adding hyaluronidase to local anaesthetic fluid on pain outcomes in people undergoing eye surgery are uncertain due to the low quality of evidence available. A well designed RCT is required to address inconsistency and imprecision among the studies and to determine the benefit of hyaluronidase to improve analgesia during eye surgery. Participant and surgical satisfaction is higher with hyaluronidase compared to the control groups, as demonstrated in moderate quality studies. There was no harm attributed to the use of hyaluronidase in any of the studies. Considering that harm was only rarely defined as an outcome measure, and the overall small number of participants, conclusions cannot be drawn about the incidence of harmful effects of hyaluronidase. None of the studies undertook cost calculations with regards to use of hyaluronidase in local anaesthetic eye blocks.

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.

Nitrous oxide-based vs. nitrous oxide-free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review

Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patient's resistance to an expected sufficient dose of such an agent. Awareness is 'explicit' if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. We included 15 randomised controlled trials, 14 of which, representing a total of 3439 participants, were included in our primary analysis of the frequency of accidental awareness events. The awareness incidence rate was rare within these studies, and all were considered underpowered with respect to this outcome. The risk of bias across all studies was judged to be high, and 76% of studies failed adequately to conceal participant allocation. We considered the available evidence to be of very poor quality. There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta- or sub-group analysis and there was insufficient evidence to draw outcome-related conclusions. We can, however, recommend that future studies focus on potentially high-risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.

Effects of epidural volume extension by saline injection on the efficacy and safety of intrathecal local anaesthetics: systematic review with meta-analysis, meta-regression and trial sequential analysis

Epidural volume extension, a modification of combined spinal-epidural anaesthesia, involves the epidural injection of saline in order to increase the spread of drugs given intrathecally. Results from individual studies have so far been contradictory and we aimed to gather the available evidence for this technique. We performed a systematic literature search for randomised, controlled trials comparing epidural volume extension after spinal injection with a control group without epidural injection in patients undergoing surgery. Conventional meta-analyses, trial sequential analyses and meta-regression were performed, with the Grading of Recommendations on Assessment, Development and Evaluation (GRADE) approach used to express reliability of outcome estimates. We included 15 studies with 1177 participants. Meta-analyses for the primary outcomes, such as maximum sensory height (6 studies, 274 participants, mean difference (MD) (95%CI) -0.59 (-1.24 to 0.07) dermatomes, low-quality evidence) and hypotension (10 studies, 683 participants, risk ratio (95%CI) 0.84 (0.66-1.07), low-quality evidence), did not differ significantly between the two treatment arms, but trial sequential analysis suggested insufficient evidence to be certain of these findings. Meta-regression suggested a volume-dependent effect, with higher volumes causing a higher spread of intrathecal drugs and a higher incidence of hypotension. A sub-group analysis indicated a pronounced effect on motor block recovery time when a lower anaesthetic dose plus epidural volume extension was compared with a higher anaesthetic dose without epidural volume extension, the MD (95%CI) being -66.75 (-76.0 to -57.5) min, with trial sequential analysis suggesting the evidence was sufficient to draw this conclusion. In trials using the same anaesthetic mixture in the epidural volume extension and the control groups, motor block recovery time did not differ between groups, with a MD (95%CI) of -1.06 (-5.48 to 3.36) min, although trial sequential analysis suggested insufficient evidence. In summary, there is not enough evidence to draw definite conclusions on the effect of epidural volume extension. The quality of the current evidence is low for both efficacy (maximum sensory height) and safety (hypotension). However, there may be a significantly shorter motor block recovery time when different anaesthetic mixtures are used in epidural volume extension and control groups; this warrants further investigation.

A network meta-analysis of the clinical properties of various types of supraglottic airway device in children

We conducted both conventional pairwise and Bayesian network meta-analyses to compare the clinical properties of supraglottic airway devices in children. We searched six databases for randomised clinical trials. Our primary end-points were oropharyngeal leak pressure, risk of insertion failure at first attempt, and blood staining risk. The risk of device failure, defined as the abandonment of the supraglottic airway device and replacement with a tracheal tube or another device, was also analysed. Sixty-five randomised clinical trials with 5823 participants were identified, involving 16 types of supraglottic airway device. Network meta-analysis showed that the i-gel™, Cobra perilaryngeal airway™ and Proseal laryngeal mask airway (LMA^® -Proseal) showed statistically significant differences in oropharyngeal leak pressure compared with the LMA^® -Classic, with mean differences (95% credible interval, CrI) of 3.6 (1.9-5.8), 4.6 (1.7-7.6) and 3.4 (2.0-4.8) cmH₂ O, respectively. The i-gel was the only device that significantly reduced the risk of blood staining of the device compared with the LMA-Classic, with an odds ratio (95%CrI) of 0.46 (0.22-0.90). The risk (95%CI) of device failure with the LMA-Classic, LMA^® -Unique and LMA-Proseal was 0.36% (0.14-0.92%), 0.49% (0.13-1.8%) and 0.50% (0.23-1.1%), respectively, whereas the risk (95%CI) of the i-gel and PRO-Breathe was higher, at 3.4% (2.5-4.7%) and 6.0% (2.8-12.5%), respectively. The risk, expressed as odds ratio (95%CrI), of insertion failure at first attempt, was higher in patients weighing < 10 kg at 5.1 (1.6-20.1). We conclude that the LMA-Proseal may be the best supraglottic airway device for children as it has a high oropharyngeal leak pressure and a low risk of insertion. Although the i-gel has a high oropharyngeal leak pressure and low risk of blood staining of the device, the risk of device failure should be evaluated before its routine use can be recommended.

High-flow nasal cannulae for respiratory support in adult intensive care patients

BACKGROUND

High-flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide-bore nasal cannulae and may be useful in providing respiratory support for adult patients experiencing acute respiratory failure in the intensive care unit (ICU).

OBJECTIVES

We evaluated studies that included participants 16 years of age and older who were admitted to the ICU and required treatment with HFNC. We assessed the safety and efficacy of HFNC compared with comparator interventions in terms of treatment failure, mortality, adverse events, duration of respiratory support, hospital and ICU length of stay, respiratory effects, patient-reported outcomes, and costs of treatment.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 3), MEDLINE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, proceedings from four conferences, and clinical trials registries; and we handsearched reference lists of relevant studies. We conducted searches from January 2000 to March 2016 and reran the searches in December 2016. We added four new studies of potential interest to a list of 'Studies awaiting classification' and will incorporate them into formal review findings during the review update.

SELECTION CRITERIA

We included randomized controlled studies with a parallel or cross-over design comparing HFNC use in adult ICU patients versus other forms of non-invasive respiratory support (low-flow oxygen via nasal cannulae or mask, continuous positive airway pressure (CPAP), and bilevel positive airway pressure (BiPAP)).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias.

MAIN RESULTS

We included 11 studies with 1972 participants. Participants in six studies had respiratory failure, and in five studies required oxygen therapy after extubation. Ten studies compared HFNC versus low-flow oxygen devices; one of these also compared HFNC versus CPAP, and another compared HFNC versus BiPAP alone. Most studies reported randomization and allocation concealment inadequately and provided inconsistent details of outcome assessor blinding. We did not combine data for CPAP and BiPAP comparisons with data for low-flow oxygen devices; study data were insufficient for separate analysis of CPAP and BiPAP for most outcomes. For the primary outcomes of treatment failure (1066 participants; six studies) and mortality (755 participants; three studies), investigators found no differences between HFNC and low-flow oxygen therapies (risk ratio (RR), Mantel-Haenszel (MH), random-effects 0.79, 95% confidence interval (CI) 0.49 to 1.27; and RR, MH, random-effects 0.63, 95% CI 0.38 to 1.06, respectively). We used the GRADE approach to downgrade the certainty of this evidence to low because of study risks of bias and different participant indications. Reported adverse events included nosocomial pneumonia, oxygen desaturation, visits to general practitioner for respiratory complications, pneumothorax, acute pseudo-obstruction, cardiac dysrhythmia, septic shock, and cardiorespiratory arrest. However, single studies reported adverse events, and we could not combine these findings; one study reported fewer episodes of oxygen desaturation with HFNC but no differences in all other reported adverse events. We downgraded the certainty of evidence for adverse events to low because of limited data. Researchers noted no differences in ICU length of stay (mean difference (MD), inverse variance (IV), random-effects 0.15, 95% CI -0.03 to 0.34; four studies; 770 participants), and we downgraded quality to low because of study risks of bias and different participant indications. We found no differences in oxygenation variables: partial pressure of arterial oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) (MD, IV, random-effects 7.31, 95% CI -23.69 to 41.31; four studies; 510 participants); PaO₂ (MD, IV, random-effects 2.79, 95% CI -5.47 to 11.05; three studies; 355 participants); and oxygen saturation (SpO₂) up to 24 hours (MD, IV, random-effects 0.72, 95% CI -0.73 to 2.17; four studies; 512 participants). Data from two studies showed that oxygen saturation measured after 24 hours was improved among those treated with HFNC (MD, IV, random-effects 1.28, 95% CI 0.02 to 2.55; 445 participants), but this difference was small and was not clinically significant. Along with concern about risks of bias and differences in participant indications, review authors noted a high level of unexplained statistical heterogeneity in oxygenation effect estimates, and we downgraded the quality of evidence to very low. Meta-analysis of three comparable studies showed no differences in carbon dioxide clearance among those treated with HFNC (MD, IV, random-effects -0.75, 95% CI -2.04 to 0.55; three studies; 590 participants). Two studies reported no differences in atelectasis; we did not combine these findings. Data from six studies (867 participants) comparing HFNC versus low-flow oxygen showed no differences in respiratory rates up to 24 hours according to type of oxygen delivery device (MD, IV, random-effects -1.51, 95% CI -3.36 to 0.35), and no difference after 24 hours (MD, IV, random-effects -2.71, 95% CI -7.12 to 1.70; two studies; 445 participants). Improvement in respiratory rates when HFNC was compared with CPAP or BiPAP was not clinically important (MD, IV, random-effects -0.89, 95% CI -1.74 to -0.05; two studies; 834 participants). Results showed no differences in patient-reported measures of comfort according to oxygen delivery devices in the short term (MD, IV, random-effects 0.14, 95% CI -0.65 to 0.93; three studies; 462 participants) and in the long term (MD, IV, random-effects -0.36, 95% CI -3.70 to 2.98; two studies; 445 participants); we downgraded the certainty of this evidence to low. Six studies measured dyspnoea on incomparable scales, yielding inconsistent study data. No study in this review provided data on positive end-expiratory pressure measured at the pharyngeal level, work of breathing, or cost comparisons of treatment.

AUTHORS' CONCLUSIONS

We were unable to demonstrate whether HFNC was a more effective or safe oxygen delivery device compared with other oxygenation devices in adult ICU patients. Meta-analysis could be performed for few studies for each outcome, and data for comparisons with CPAP or BiPAP were very limited. In addition, we identified some risks of bias among included studies, differences in patient groups, and high levels of statistical heterogeneity for some outcomes, leading to uncertainty regarding the results of our analysis. Consequently, evidence is insufficient to show whether HFNC provides safe and efficacious respiratory support for adult ICU patients.