Transporting critically ill patients between medical facilities can be hazardous and costly. Whether by road, fixed-wing aircraft or helicopter, many professional associations have proposed strategies to efficiently and safely transport patients at high risk of instability. Although these strategies have been assessed in some studies, no comprehensive synthesis of their benefits has been conducted to date. The aim of this study is to assess the effect of strategies to improve the safety and costs of interhospital transports for critically ill patients.

We will conduct a systematic review according to the Cochrane guidelines. The review will include randomised controlled trials (RCTs), cohort studies and case-control studies assessing the effect of interventions to improve interhospital transports of critically ill patients on safety and costs. We will search multiple electronic databases (PubMed, EMBASE, CINAHL, Web of Science, Cochrane Library) from inception to 6 months prior to the submission of the final manuscript. Screening by title and abstract, full-text screening, data extraction and quality assessment will be performed by two independent reviewers. We will assess the risk of bias with the Cochrane revised tool for RCTs and with the risk of bias in non-randomised studies of interventions tool. If possible, we will calculate pooled effect estimates and 95% CIs to assess the effect of the interventions. We will also assess heterogeneity using the I² index and rate the certainty of evidence with the Grading of Recommendations Assessment, Development and Evaluation tool and trial sequential analysis.

Ethics approval is not required for this review. The results of this systematic review will be shared through publication in a peer-reviewed journal, conference presentations and our network of knowledge user collaborators.

International Prospective Register of Systematic Reviews (CRD42024595080).

To examine changes in cardiovascular disease (CVD) risk factors, lung function and clinical laboratory markers among people who smoke who used e-cigarettes to reduce their cigarette smoking.

Four-arm, parallel-group, double-blind, randomised placebo-controlled trial.

Two sites—Virginia Commonwealth University (Richmond, Virginia, USA) and Penn State University, College of Medicine (Hershey, Pennsylvania, USA).

Adults (n=520) aged 21–65 years who smoked at least 10 cigarettes per day, had an expired-air carbon monoxide reading of >9 parts per million at baseline and were interested in reducing their cigarette consumption.

E-cigarettes with 0, 8 or 36 mg/mL nicotine liquid concentration or a cigarette substitute.

CVD risk factors (blood lipids, C-reactive protein, blood pressure, heart rate, waist-to-hip ratio, body mass index and INTERHEART risk score), lung function (spirometry indices, and pulmonary symptoms and functional state using the Clinical Chronic Obstructive Pulmonary Disorder Questionnaire), and other clinical laboratory markers (complete blood count and complete metabolic panel).

At 6 months, the use of nicotine e-cigarettes caused no significant between-group differences for most measures. However, participants randomised to the 36 mg/mL e-cigarette condition had significantly higher levels of high-density lipoprotein (HDL) (p=0.003 unadjusted, p=0.002 adjusted) and lower levels of low-density lipoprotein (LDL) (p=0.044 adjusted) and cholesterol/HDL ratio (p=0.034 unadjusted, p=0.026 adjusted) compared with the cigarette substitute condition. Also, those in the 36 mg/mL e-cigarette condition had higher HDL levels than those in the 0 mg/mL condition (p=0.016 unadjusted, p=0.019 adjusted).

Participants randomised to the highest nicotine e-cigarette condition showed modest improvements in some measures of blood lipids (eg, increased HDL, and reduced LDL and cholesterol/HDL ratio) as compared with a non-aerosol cigarette substitute among individuals attempting to reduce their cigarette smoking. Future studies of e-cigarettes for smoking cessation would benefit from including these measures to further explore the results found in this study.

NCT02342795.