Effects of Continuous Mobility Training in Prolonged Mechanical Ventilation

Background: The exercise intervention can help participants with prolonged mechanical ventilation improve ventilator weaning; however, the content of exercise intervention is diverse and inconsistent.

Objective: This study aims to design the continuous mobility training and examine the clinical effects in participants with prolonged mechanical ventilation.

Methods: This prospective, single-center, concealed allocation, evaluator-blind, randomized control study divided participants transferred from the intensive care unit to the respiratory care center into two groups. The control group underwent the routine ventilator weaning plan and hand bicycle training, while the experimental group underwent routine ventilator weaning plan and continuous mobility training plan. The success rate of ventilator weaning, length of mechanical ventilation, length of stay at the respiratory care center, and total length of hospital stay were analyzed.

The investigators designed a prospective, single-center, concealed allocation, evaluator-blind, intention-to-treat, randomized control study.

Participants This study was at the respiratory care center of a hospital in Taiwan. Individuals over 18 years of age, who used mechanical ventilation, were transferred from the intensive care unit to the respiratory care center for mechanical ventilation weaning, and were evaluated by a physician enrolled in the study. When a patient was eligible, the physician would conduct further examinations to ensure the suitability and safety of the participants, and the reasons for ineligibility for inclusion would be noted in the log.

Inclusion criteria:

1. Aged over 18 years, regardless of sex.
2. Use of mechanical ventilation and transfer from the intensive care unit to the respiratory care center for weaning.
3. Stable vital signs.
4. Ability to understand simple instructions and agree to participate in this research program after explanation.

Exclusion criteria:

1. Unconsciousness, severe cognitive impairment, or inability to follow instructions.
2. Severe heart failure (NYHA ≥ 3).
3. Diagnosis of terminal illness and undergoing palliative care.
4. Inability to receive exercise therapy due to physical conditions, fracture, lower limb surgery, acute thrombosis, open wounds, extracorporeal membrane oxygenation.
5. Assessment by other attending physician that the participant's condition, progression of disease course or treatment plan were not suitable for exercise therapy.

When the participants enrolled in the research, the trained research team members would explain the objectives and methods of the research to ensure that the participants' consent was fully informed. The participants had the right to withdraw from this research program at any time. If a participant was unwilling to participate or withdrew, they were excluded from this research program. A participant could only be enrolled after agreeing and signing the consent form. A randomized clinical trial design was adopted in this study. The participants were randomly divided into the experimental and control group in a one-to-one ratio. The research assistant placed the number plate in an opaque and sealed envelope to ensure concealed allocation. The order of allocation was randomized by the computer. The control group underwent the routine mechanical ventilation weaning plan and hand bicycle training, while the experimental group underwent the routine mechanical ventilation weaning plan and continuous mobility training. Owing to the nature of the exercise intervention, it is impossible to maintain blinding of the team members and participants. However, the physical therapists who evaluated the main outcome were separated from those who performed the therapy; thus, the evaluators were blinded. The content of the continuous mobility training program depended on the evaluation results and the physical responses of the participants. The treatment frequency of continuous mobility training was five times a week, once a day from Monday to Friday.

Intervention content Control group: Participants of control group formed the routine care group, received the routine mechanical ventilation weaning plan and underwent hand bicycle training. The physicians assessed the participants and appropriately adjusted the settings of the mechanical ventilation modules to gradually reduce the participants' dependence on mechanical ventilation. Hand bicycle training was conducted by nurse practitioners once a day. The participants' bedhead was raised, and the participants held the cycle ergometer with both hands once they could tolerate upright positions for 15-20 minutes. Training intensity was targeted at the level of symptom limitation, on the basis of a modified Borg scale rating of 3-5. Intermittent and short-term periods of rest were allowed for participants to achieve the goal of a total of 15-20 minutes exercise session.

Experimental group: Participants of the experimental group were given continuous mobility training in addition to the routine mechanical ventilation weaning plan. The protocol was divided into 5 levels - a modification from Dong et al. The physicians were responsible for evaluating whether the participants had any contraindications before and during enrolment. If any contraindication occurred at any time point, such as hypoxemia and other adverse events, the treatment would be terminated immediately. The continuous mobility training would be performed once a day from Monday to Friday. During the whole continuous mobility training process, the exercise progress would be increased gradually, depending on the tolerance and stability of the participants. The goal setting of each training exercise was that the participants could undergo the training for 20 minutes continuously.

The continuous mobility training adopted grading exercise level, which was evaluated and implemented by physical therapists, and focused on continuous mobility training courses with different levels. At each stage, the participants were instructed to perform spontaneous breathing exercise, which were confirmed by the physical therapists. In the first stage, the participants' bedhead were raised, and the trunk were kept upright on the bed. In sitting posture training, chest expansion training and deep breathing training was performed. The training goal was that the participants should be able to sit in bed for at least 20 minutes, and after training, the modified Borg scale rating of the participants should not exceed 7. If the participants could successfully complete the first stage of the exercise training, they would proceed to the next stage of exercise, and the training would be further upgraded to assisting the participants to sit at the bedside in an upright posture and perform sitting balance training. The physical therapists would provide minimal assistance or assistive devices according to the participants' conditions. The goal was to achieve tolerance for 20 minutes continuously with a modified RPE not exceeding 7 and no contraindications. In the third stage, the physical therapists would adopt appropriate strategies and assistive devices according to the participants' abilities and move the participants to chairs. The fourth stage was standing training. The participants could use assistive devices or other assistance to stand. The fifth stage was marching on spot. All exercise training was guided by the principle of maximum active participation of participants, with the goal of continuous completion of body movements and spontaneous breathing movements.

Termination conditions of continuous mobility training: The training would be terminated immediately if the participants had the following conditions:

1. Unstable vital signs: low blood oxygen concentration (SaO2 ≤ 90%) or shortness of breath (total respiratory rate \> 35 beats/min).
2. Arrhythmia.
3. Severe dizziness.
4. Changes in consciousness.
5. Assessment by attending physician that the participant's condition, progression of disease course or treatment plan was not suitable for activities of exercise therapy.

After the intervention, the length of mechanical ventilation, length of stay in the respiratory care center, the success rate of mechanical ventilation weaning (weaning for more than 5 days), the total length of hospital stay and adverse events of two groups were recorded with evaluator-blind.

Data analysis All participants were included in the intention-to-treat analysis. The mean, standard deviation, and percentage of the participants' variables were used for descriptive statistics. Comparative analysis between the experimental group and the control group was performed according to all the effect variables. If the continuous variables conformed to normal distribution according to Shapiro-Wilk test, they were expressed as mean±standard deviation (mean±SD); otherwise, they were expressed as median (interquartile range). Categorical variables were expressed as percentage.

The evaluation records of the two groups of participants were compared, and continuous variables with normal distribution were compared by two sample independent t-test. When the data were not normally distributed, Mann-Whitney U test was used to compare the experimental group with the control group. Chi-square test was used to evaluate the differences in the categorical variables between the experimental group and the control group. To calculate the sample size for duration of mechanical ventilation, the investigators based the design on results found in Lai (2017) for a clinical trial. Considering a statistical power of 90% and alpha error of 0.5, the investigators found that the number of subjects should be 9 per group, totaling 18 participants. The statistical analysis software used was SPSS version 27.0, with 2-tailed p\<.05 indicating statistical significance.

Eligibility Criteria:
Inclusion criteria:

1. Aged over 18 years, regardless of sex.
2. Use of mechanical ventilation and transfer from the intensive care unit to the respiratory care center for weaning.
3. Stable vital signs.
4. Ability to understand simple instructions and agree to participate in this research program after explanation.

Exclusion criteria:

1. Unconsciousness, severe cognitive impairment, or inability to follow instructions.
2. Severe heart failure (NYHA ≥ 3).
3. Diagnosis of terminal illness and undergoing palliative care.
4. Inability to receive exercise therapy due to physical conditions, fracture, lower limb surgery, acute thrombosis, open wounds, extracorporeal membrane oxygenation.
5. Assessment by other attending physician that the participant's condition, progression of disease course or treatment plan were not suitable for exercise therapy.