Progressive mobility program and technology to increase the level of physical activity and its benefits in respiratory, muscular system, and functionality of ICU patients: study protocol for a randomized controlled trial

A large number of patients who survive hospitalization in the Intensive Care Unit (ICU) experience negative effects of critical illness, even after stabilization of the condition, presenting cognitive, psychological, and physical changes as the main morbidities. In a prospective cohort study of 1075 patients 5 months after discharge, 48% of patients needed help in at least one activity of daily life [1]. Data show that 1 year after their stay in ICU, patients still reported muscle weakness, loss of muscle mass, and fatigue, and half of those patients had not yet returned to occupational tasks [2]. Even after 5 years, some of these changes persisted in most patients [3]. In another study, quality of life was evaluated at 1 year and 4 years after hospital discharge, with results indicating a decrease in quality of life in surviving patients due mainly to a decrease in physical function [4].

These medium and long-term consequences originate at the beginning of hospitalization and are related to changes that occurred during the stay in the ICU. In this period, patients may experience a period of inactivity and prolonged rest resulting in immobility, related to changes in various systems of the body. In the respiratory system, the main consequences of this immobilization are atelectasis, mechanical ventilation (MV), and hospital-associated pneumonia as well as delayed removal of the MV due to muscle weakness, decreased vital capacity, and residual volume [5, 6].

Studies of immobility in bed have shown a decrease in strength and muscle mass with variations similar to the losses experienced during ICU stays, with a decline of 1–1.5% per day and up to 50% of total muscle mass in 2 weeks [5]. In healthy people, immobilization has been shown to induce muscle atrophy, characterized by decreased protein content, fiber diameter, fatigue resistance, and strength [7]. Signs of cardiovascular dysfunction are observable within 3 to 4 days of immobility in the bed [8]. These effects, seen in healthy, bed-restricted patients may be potentially relevant for ICU patients who also present with fluid loss, as evidenced by a decrease in plasma volume of 10–20%. This decrease contributes to postural hypotension and tachycardia as well as decreased systolic volume, ejection volume, cardiac output, and oxygen uptake [9, 10].

In the ICU, in addition to immobility, muscular dysfunction is common due to multiple factors such as inflammation, the use of pharmacological agents (corticosteroids, muscle relaxants, or antibiotics) and the presence of neuromuscular syndromes associated with critical illnesses: critical illness myopathy and polyneuropathy [6, 8, 11‐13]. Peripheral muscle weakness has been reported in 25–33% of patients undergoing MV for 4 to 7 days and in 60% of patients with respiratory failure [14, 15].

In light of these facts, interventions that encourage greater mobility in and out of bed during hospitalization are necessary to avoid or minimize losses associated with immobility and inactivity. The European Respiratory Society and the European Society of Intensive Care recommend starting these interventions as early as possible in critical patients, which can be done through both passive and active exercises [16]. Recent studies have indicated that early activity for ICU patients is safe and feasible, and results in a larger number of patients who leave the ICU functionally independent. Of all patients discharged from the ICU, those who underwent early mobilization left with fewer complications related to immobility and with improved functionality [17‐19].

Among the benefits described in the academic literature on early mobility are increased days free of MV, reduced incidence of ventilator-associated pneumonia, reduced skin lesions, reduced days of hospital and ICU stay, decreased duration of delirium, and improved physical function at hospital discharge [5, 17, 19, 20].

There is no clear consensus on the ideal prescription for patients in ICU; however, the American College of Sports Medicine proposes a basic program [21]. The program should include a prescription of intensity, volume, and frequency for each patient to optimize the benefits from physical activity, even for ICU patients and those with respiratory insufficiency [7]. However, there are no guides or well-established practices for early and progressive mobility in the ICU. Determining the optimal initiation and progression of physical exercises can enhance beneficial effects of the protocol. Studies of current mobility protocols are still scarce in the academic literature of physical activity.

Rehabilitation programs within the ICU have been proposed, but the academic literature describes some limitations to early mobility in critical patients such as a lack of knowledge among professionals about early mobility, sedation practices, and insufficient numbers of professionals or equipment [5, 22]. Since a shortfall of professionals and a lack of equipment are cited as barriers to rehabilitation programs, the use of technology has emerged as a possible way to provide such services. Thus, the introduction of rehabilitation technologies, such as equipment for strength exercises, neuromuscular electrical stimulation, cycle ergometers, and equipment for walking can be an important factor in improving muscle strength, cardiopulmonary function, and functionality for patients in intensive care. Virtual reality has been suggested as a tool to improve certain cognitive functions. This is because exercise linked to virtual reality is able to offer demands that include multitasking, inhibition, taskswitching, short-term/working memory, and intelligence. Games can offer cognitive work since they generate cognitive demands such as: plan movements in order to hit targets, response inhibition, divide attention between tasks, sustain attention, follow visual and auditory cues, identify stimulus and decide quickly [23]. In the ICU, the use of these technologies, along with mobility programs, requires a thorough evaluation of the potential benefits and the safety, practicality, and efficacy.

Therefore, we created an early and progressive mobilization program based in four areas—muscle, cardiovascular, respiratory, and cognitive activities—to promote appropriate functional capacity and performance. The program includes exercises to maintain or recover basic function and to integrate these systems, preserving or recovering patients’ functionality even during hospitalization in the ICU.

The study’s hypothesis is that a progressive mobilization protocol and the use of technology is superior to conventional physiotherapy in promoting activity levels in the ICU and provides greater functional capacity at ICU discharge. Given evidence that points to the benefits of early mobilization, we chose to use conventional physiotherapy with the control group.

The main objective of this protocol will be to compare the use of an early and progressive mobility program designed to increase the level of physical activity with a conventional therapy program and assess its benefits for the respiratory, muscular, and functional systems of patients in the ICU. Objective descriptions of the intensity of exercise performed in the ICU are scarce in the academic literature.

Physiotherapy in clinical practice differs greatly in character between care services. Variation in the supply and types of treatments available within the ICU may be the main difficulty in achieving greater benefits, and standardization with early and progressive programs, with the patient being included at most appropriate level of the program (i.e., the maximum the patient can do at that moment), may be the key to better outcomes. Other procedures used in the ICU, such as weaning from MV, weaning from sedation and therapies for sepsis have previously been addressed and are implemented using defined protocols [18].

A study conducted in ICUs in Australia showed that, although the vast majority of physiotherapists routinely prescribed exercises in the ICU, practices varied widely across the country, and it was also found that the results of the therapies were not measured. These results led to the conclusion that future research is necessary for adequate and improved exercise prescription in ICUs [33].

As with other therapies, mobility and exercise in the ICU should be planned in terms of intensity, quantity, duration, and frequency. It is important that physiotherapy in the ICU also has directions and protocols for these characteristics [5]. Studies of current mobility protocols are still scarce, especially regarding physical activity characteristics, such as exercise intensity [13].

We hope that the early and progressive rehabilitation program will result in a higher level of physical activity during ICU admission and thus will also result in improved functional indexes and muscle and respiratory functions at ICU discharge. Also, we hope that our results will contribute to scientific knowledge about the benefits of physical activity in the ICU and help to direct physiotherapeutic activity in this environment, bringing benefits to patients and the health care system (Additional file 1).