Introduction
Patients surviving critical illness are at risk of significant physical disability up to 8 years after discharge from the intensive care unit (ICU).1 2 Patients admitted to ICU have increased morbidity and case complexity, and more are surviving after critical illness.3 In a prospective cohort study of 391 medical surgical ICU survivors, function at 7 days post-ICU predicted function 1 year later, suggesting that rehabilitation interventions initiated during or immediately after ICU discharge could improve long term outcomes.4
However, important barriers to conducting early rehabilitation early in a patient’s ICU stay exist, including the presence of an endotracheal tube and the use of vasoactive medications and continuous sedation.5 In-bed cycling started in the ICU can improve physical function at hospital discharge and is a promising early intervention for mechanically ventilated (MV) patients. During cycling, patients can transition from passive to active cycling, while intubated and receiving vasoactive medications or sedative infusions.6
While several studies document the feasibility or safety6–9 of in-bed cycling, surprisingly few randomised clinical trials (RCTs) exist. In a 90-patient RCT, those who started cycling 14 days after ICU admission had farther 6 min walk test scores at hospital discharge.10 In an RCT of 21 patients with sepsis, those who received short-term early cycling demonstrated preserved muscle fibre cross-sectional area at 7 days.11 In a 49-patient RCT, those who started passive cycling 3 days after ICU admission had larger improvements in strength scores at ICU discharge.12 However, in a recent RCT of 314 patients that added both in-bed cycling and neuromuscular electrical stimulation to early mobilisation in critically ill patients did not improve muscle strength at ICU discharge.13 The functional impact of early cycling alone on MV patients within the first week of ICU admission has not been evaluated.
Before embarking on a large RCT, a pilot RCT is needed for several reasons.14 Despite widespread awareness of in-bed cycling, this technology is not commonly available in ICUs.15 Previous studies documented important methodological challenges conducting rehabilitation RCTs with critically ill patients including suboptimal recruitment,16 17 impaired intervention delivery18 and losses to follow-up.19 Our objective was to conduct a pilot RCT to assess the feasibility of recruitment, intervention delivery and retention to inform a larger RCT.14 20