Early in-bed cycle ergometry can shorten ICU stays and enhance physical function in critically ill patients, offering a safe and effective rehabilitation strategy for quicker recovery.

Study: Leg Cycle Ergometry in Critically Ill Patients — An Updated Systematic Review and Meta-Analysis. Image Credit: sfam_photo / Shutterstock

A study finds that cycling with critically ill patients may reduce the length of stay in the ICU or hospital and improve physical function at ICU or hospital discharge without affecting other outcomes, including mortality. However, these findings are based on low to very low certainty of evidence, which tempers the strength of the conclusions.

A recent European Society of Intensive Care Medicine study aimed to summarize and systematically review existing evidence on the safety and efficacy of cycle ergometry in the intensive care unit (ICU).

Physical rehabilitation interventions and cycle ergometry 

Physical rehabilitation interventions should be initiated in the ICU to prevent post-ICU impairments. However, the existing literature documents several different types of interventions, and there is a lack of guidance on the timing or type of rehabilitation activity. Some randomized clinical trials (RCTs) on ICU-based physical rehabilitation interventions showed higher ICU mobility, improved cognitive function, and better physical function. However, others found no difference in length of stay or physical function or with rehabilitation.

Cycle ergometry is an ICU-based rehabilitation intervention that can be initiated while a patient is sedated, bed-bound, and mechanically ventilated. Several trials have evaluated this intervention as one aspect of a multicomponent rehabilitation strategy or in isolation. The current study summarizes all available trial evidence and addresses whether ICU-based cycling improves physical function among adults admitted to the ICU relative to any comparator. 

About the study

RCTs of adults who were critically ill and admitted to the ICU for more than 24 hours were included. Cycling interventions (as part of a multifaceted strategy or in isolation) were compared to other interventions that did not include cycling. Besides the focus on physical function, other factors were considered, such as muscle strength, duration of mechanical ventilation, ICU-acquired weakness (ICUAW), length of hospital stay, mortality, and so on.

Outcomes were documented at three points in time: discharge from the ICU, hospital discharge, and the nearest measure post–hospital discharge. For each time period, all functional measures were identified across included trials, which led to the detection of the most common outcome at that time point. For multiple physical functional outcome reports, the one related to the cycling intervention was selected.

Study findings

A total of 33 trials between 1998 and 2024 were included, with 3274 critically ill patients enrolled. Among these, 1648 were allocated to cycling, while the remaining were allocated to control. The trials were conducted in thirteen countries, were mostly single centers, and had an average sample size of 74. Four trials examined cycling alone, eleven examined cycling plus usual physiotherapy, three assessed cycling plus electrical stimulation and usual physiotherapy, and fifteen examined cycling as part of a multicomponent intervention.

The quality of reporting was assessed using the Consensus on Exercise Reporting Template (CERT). CERT reporting scores were calculated as a percentage, and 70% and above scores were considered adequate, between 50 and 70% were considered moderate, and less than 50% were considered poor. Across the trials, the median CERT score was 61.5%, ranging from 52.6% to 75%. Furthermore, intervention groups were reported better than comparators. Cycling parameters were well reported, with 29 trials reporting cycling intensity, 30 trials reporting frequency, 32 trials reporting duration, and 27 trials reporting timing.

Results from twelve and eight RCTs showed that cycling improved physical function at ICU discharge and post-hospital discharge, respectively. No distinction could be made between the efficacy of cycling alone or as part of a multicomponent intervention. In 29 trials, cycling decreased the length of ICU stay, and in 22 trials, it reduced the length of hospital stay. Despite these positive findings, the evidence for most outcomes was classified as low to very low certainty, which means further research may alter the results.

Overall, the results suggested that cycling may have had no effect on ICU mortality and adverse events. It was also inconclusive whether cycling influenced post-hospital or hospital mortality. Adverse events were rare in cycling intervention groups and comparator groups. The event rates were in the range of 1-2% by patient and by session. This highlights the safety of cycling as an intervention, with very low adverse event rates reported in both intervention and comparator groups. Furthermore, five trials showed that cycling may enhance muscle strength at hospital discharge, but the efficacy of cycling concerning the reduction of ICUAW at ICU discharge was not established conclusively.

Conclusions

In sum, this study documented that cycling could improve physical function among critically ill patients at ICU discharge and after hospital discharge. Additionally, cycling could reduce the length of ICU and hospital stays without influencing other outcomes such as mortality. However, it is important to recognize that the findings are based on evidence with low certainty, particularly for functional outcomes at hospital discharge.

The study’s strengths revolve around including the most recently published and most extensive trials of in-bed cycling in critically ill patients. Furthermore, the methods used were robust, and results were transparently reported to aid replication. Nonetheless, limitations include the lack of universally agreed-upon outcome measures, the variability in how usual care in control groups was described, and the small number of multicenter trials, especially in low-income countries.