Spin and fragility in randomised controlled trials in the anaesthesia literature: a systematic review

Narrative bias ("spin") is common in randomised trials and systematic reviews of cannabinoids for pain

ABSTRACT

We define narrative bias as a tendency to interpret information as part of a larger story or pattern, regardless of whether the facts support the full narrative. Narrative bias in title and abstract means that results reported in the title and abstract of an article are done so in a way that could distort their interpretation and mislead readers who had not read the whole article. Narrative bias is often referred to as "spin." It is prevalent in abstracts of scientific papers and is impactful because abstracts are often the only part of an article read. We found no extant narrative bias instrument suitable for exploring both efficacy and safety statements in randomized trials and systematic reviews of pain. We constructed a 6-point instrument with clear instructions and tested it on randomised trials and systematic reviews of cannabinoids and cannabis-based medicines for pain, with updated searches to April 2021. The instrument detected moderate or severe narrative bias in the title and abstract of 24% (8 of 34) of randomised controlled trials and 17% (11 of 64) of systematic reviews; narrative bias for efficacy and safety occurred equally. There was no significant or meaningful association between narrative bias and study characteristics in correlation or cluster analyses. Bias was always in favour of the experimental cannabinoid or cannabis-based medicine. Put simply, reading title and abstract only could give an incorrect impression of efficacy or safety in about 1 in 5 papers reporting on these products.

Effects of closed loop ventilation on ventilator settings, patient outcomes and ICU staff workloads - a systematic review

BACKGROUND

Lung protective ventilation is considered standard of care in the intensive care unit. However, modifying the ventilator settings can be challenging and is time consuming. Closed loop modes of ventilation are increasingly attractive for use in critically ill patients. With closed loop ventilation, settings that are typically managed by the ICU professionals are under control of the ventilator's algorithms.

OBJECTIVES

To describe the effectiveness, safety, efficacy and workload with currently available closed loop ventilation modes.

DESIGN

Systematic review of randomised clinical trials.

DATA SOURCES

A comprehensive systematic search in PubMed, Embase and the Cochrane Central register of Controlled Trials search was performed in January 2023.

ELIGIBILITY CRITERIA

Randomised clinical trials that compared closed loop ventilation with conventional ventilation modes and reported on effectiveness, safety, efficacy or workload.

RESULTS

The search identified 51 studies that met the inclusion criteria. Closed loop ventilation, when compared with conventional ventilation, demonstrates enhanced management of crucial ventilator variables and parameters essential for lung protection across diverse patient cohorts. Adverse events were seldom reported. Several studies indicate potential improvements in patient outcomes with closed loop ventilation; however, it is worth noting that these studies might have been underpowered to conclusively demonstrate such benefits. Closed loop ventilation resulted in a reduction of various aspects associated with the workload of ICU professionals but there have been no studies that studied workload in sufficient detail.

CONCLUSIONS

Closed loop ventilation modes are at least as effective in choosing correct ventilator settings as ventilation performed by ICU professionals and have the potential to reduce the workload related to ventilation. Nevertheless, there is a lack of sufficient research to comprehensively assess the overall impact of these modes on patient outcomes, and on the workload of ICU staff.

Effect of Volatile Anesthesia Versus Intravenous Anesthesia on Postoperative Pulmonary Complications in Patients Undergoing Minimally Invasive Esophagectomy: A Randomized Clinical Trial

BACKGROUND

The effect of intraoperative anesthetic regimen on pulmonary outcome after minimally invasive esophagectomy for esophageal cancer is yet undetermined. The aim of this study was to determine the effect of volatile anesthesia (sevoflurane or desflurane) compared with propofol-based intravenous anesthesia on pulmonary complications after minimally invasive esophagectomy.

METHODS

Patients scheduled for minimally invasive esophagectomy were randomly assigned to 1 of 3 general anesthetic regimens (sevoflurane, desflurane, or propofol). The primary outcome was the incidence of pulmonary complications within the 7 days postoperatively, which was a collapsed composite end point, including respiratory infection, pleural effusion, pneumothorax, atelectasis, respiratory failure, bronchospasm, pulmonary embolism, and aspiration pneumonitis. The severity of pulmonary complications, surgery-related complications, and other secondary outcomes were also assessed.

RESULTS

Of 647 patients assessed for eligibility, 558 were randomized, and 553 were analyzed. A total of 185 patients were assigned to the sevoflurane group, 185 in the desflurane, and 183 in the propofol group. Patients receiving a volatile anesthetic (sevoflurane or desflurane) had a significantly lower incidence (36.5% vs 47.5%; odds ratio, 0.63; 95% confidence interval, 0.44-0.91; P = .013) and lower severity grade of pulmonary complications (P = .035) compared to the patients receiving propofol. There were no statistically significant differences in other secondary outcomes between the 2 groups.

CONCLUSIONS

In patients undergoing minimally invasive esophagectomy, the use of volatile anesthesia (sevoflurane or desflurane) resulted in the reduced risk and severity of pulmonary complications within the first 7 postoperative days as compared to propofol-based intravenous anesthesia.

Randomized Controlled Trials in ICU in the Four Highest-Impact General Medicine Journals

OBJECTIVE

To study ICU trials published in the four highest-impact general medicine journals by comparing them with concurrently published non-ICU trials in the same journals.

DATA SOURCES

PubMed was searched for randomized controlled trials (RCTs) published between January 2014 and October 2021 in the New England Journal of Medicine , The Lancet , the Journal of the American Medical Association , and the British Medical Journal.

STUDY SELECTION

Original RCT publications investigating any type of intervention in any patient population.

DATA EXTRACTION

ICU RCTs were defined as RCTs exclusively including patients admitted to the ICU. Year and journal of publication, sample size, study design, funding source, study outcome, type of intervention, Fragility Index (FI), and Fragility Quotient were collected.

DATA SYNTHESIS

A total of 2,770 publications were screened. Of 2,431 original RCTs, 132 (5.4%) were ICU RCTs, gradually rising from 4% in 2014 to 7.5% in 2021. ICU RCTs and non-ICU RCTs included a comparable number of patients (634 vs 584, p = 0.528). Notable differences for ICU RCTs were the low occurrence of commercial funding (5% vs 36%, p < 0.001), the low number of RCTs that reached statistical significance (29% vs 65%, p < 0.001), and the low FI when they did reach significance (3 vs 12, p = 0.008).

CONCLUSIONS

In the last 8 years, RCTs in ICU medicine made up a meaningful, and growing, portion of RCTs published in high-impact general medicine journals. In comparison with concurrently published RCTs in non-ICU disciplines, statistical significance was rare and often hinged on the outcome events of just a few patients. Increased attention should be paid to realistic expectations of treatment effects when designing ICU RCTs to detect differences in treatment effects that are reliable and clinically relevant.

Spin and fragility in anaesthesia studies: when sirens sing into anaesthetists' ears

Spin and fragility are common in randomised controlled trials published in anaesthesia journals. Staying with the facts and addressing only the primary endpoint in the conclusion of clinical research reports might help reduce spin. Routinely reporting the fragility index, in turn, could deliver information about robustness, enhancing the transparency of positive dichotomous results. It is in the best interest of clinical research that authors, reviewers, and journals come together to reduce spin and address the fragility of randomised controlled trials.