Vibrotherapy in intensive care units; implications for the fight against COVID-19

Whole body vibration (WBV) training can affect the neuromuscular system even in unconscious patients because the signals affecting muscle contractions can be controlled by the spinal cord without the cerebral cortex involvement. In addition, as already shown in healthy volunteers, athletes, the elderly, and patients in various hospital departments outside the Intensive Care Units (ICU), prolonged administration of WBV helps maintain muscle mass and strength, increases bone density, improves recovery, and increases glucose metabolism. These benefits meet the needs of critically ill patients and can aid recovery, although appropriate testing has not yet been conducted. Therefore, the goal of the Charite Hospital researchers (Berlin University) was to investigate the safety and feasibility of vibrotherapy in critically ill (mechanically ventilated) patients. The metabolic response to WBV was also analyzed. {Since the severe course of COVID-19 is often associated with ICU care and mechanical ventilation, and the pandemic of COVID-19 continues, the editors would like to emphasize the importance of the presented article also in the context of COVID-19 treatment/ rehabilitation. Editorial note.}

• All patients completed the experimental protocol. Vibration training did not cause any side effects.
• None of the devices, such as the endotracheal tube, endotracheal cannula, drain, etc., were moved.
• Baseline vital signs did not change significantly during and after the intervention as compared to baseline.
• In the passive phase of physiotherapy without WBV, diastolic blood pressure was significantly increased compared to the baseline values ​​(by about 2 mmHg), which was not present in the WBV exercise phase or in the following rest phase.
• Heart rate, mean arterial pressure, systolic blood pressure, and blood oxygen saturation did not differ significantly from baseline values ​​during physical therapy without WBV, during WBV exercise, or during rest after intervention.
• Both passive physiotherapy and WBV training had no significant effect on cardiac output (CO), mean stroke volume (MSV) and its range. These parameters also remained stable during rest.
• In the phase of passive physiotherapy without WBV, the variability of MSV increased significantly, while the variability of MSV did not change significantly under the influence of WBV training or during rest periods, compared to the baseline state.
• Increased energy expenditure was observed only during WBV training. Compared to the initial phase, the levels of oxygen uptake (by approx. 30 ml/min) and carbon dioxide production (by approx. 20 ml/min) were increased in the WBV training phase, showing an increased energy expenditure (by approx. 200 kcal/24h).
• Physiotherapy without WBV, as well as WBV training, significantly increased the respiratory rate compared to the baseline values ​​(by about 1.5 or about 1.8 breaths/min, respectively).
• Gasometry showed stable ventilation of patients throughout the study, as evidenced by unchanging pO2 and pCO2 values, acid-base status and pulse oximetry.
• WBV training was associated with a significant increase (by approx. 0.05 mmol/l) in serum potassium compared to the baseline values. This effect was not observed during the physiotherapy phase without WBV.

Prepared on the basis of:

Whole-body vibration to prevent intensive care unit-acquired weakness: safety, feasibility, and metabolic response. Wollersheim T et al. Crit Care. 2017 Jan 9;21(1):9.

Study population

Nineteen people were qualified for the research. The following exclusion criteria were used: no informed consent (obtained from a legal representative), age <18 years, previous neuromuscular disease, implanted pacemaker or defibrillator, pregnancy, acute venous thrombosis, unhealed fractures or recently placed implants in the vicinity of the body that were to be stimulated, recent eye surgery, a history of herniated discs with acute symptoms, being a participant in another study, as well as terminal cases.

Test procedure

The full intervention lasted 90 min. According to the previously defined protocol, the following experimental phases were established:

1. baseline (10 min),
2. passive physiotherapy phase (without WBV; 7.5 min),
3. WBV training/ exercise phase (15 min),
4. early phase of rest (10 min),
5. late phase of rest (47.5 min).

To analyze the metabolic response to the intervention, pO2, pCO2, pH, sodium, potassium and serum glucose levels were measured with an ABL 800 radiometer. From the start of measurements to 1 hour after the intervention, vital signs, circulatory dynamics and energy metabolism were continuously monitored. Serum biochemical analysis was performed at the end of phases 1, 3, 4, and 5. Gasometric analysis was performed at the end of each phase. Additionally, before and twice after the intervention, serum levels of systemic anabolic and catabolic hormones significantly affecting skeletal muscles, represented by insulin-like growth factor I (IGF-I) and cortisol, were examined. Both hormones showed significant changes under the influence of WBV in healthy subjects of previous studies.

The patients were in the supine position throughout the intervention. The position of the body was not changed so as not to disturb the measured vital and circulatory parameters.

Criteria for terminating the WBV session were defined. Treatments were to be stopped if any of the events occurred: heart rate <40 or >180 beats per minute, systolic blood pressure <80 or >200 mmHg, mean blood pressure <60 or >120 mmHg, increase in intracerebral pressure >20 mmHg, SpO2 <88%, potassium level <3.0 or >5.5 mmol/L.

Use of vibration in the study

After measurements at the end of the baseline phase, patients were passively mobilized by the physiotherapist for 6 min as a warm-up. Patients were then prepared for WBV training and vibration delivery was initiated from a vibration device positioned under the patient’s feet. The patient’s hips and knees were bent approximately 20°. The feet were pressed against a vibration device by an elastic belt around the knees. The WBV sessions lasted 15 min, with the vibrations administered intermittently for a total of 9 min. Two different devices were used: one generating synchronous vibrations (Promedi, Vibrosphere®, 26 Hz, 9 x 1 min), the other – generating vibrations alternating with the sides of the body (Galileo, home-ICU®, 24 Hz, 3 x 3 min).

Results

All patients completed the experimental stages. The vibration training did not cause any side effects in any of the patients. None of the devices, such as the endotracheal tube, endotracheal cannula, tubing, infusion line, ECMO-central intravenous catheter-cannula, or dialysis catheter were displaced. The use of WBV was a simple procedure for a physiotherapist and did not interfere with clinical practice any more than standard physiotherapy. Preparation for WBV training was easy and took less than 3 min.

Vital signs

Vital signs did not change significantly during and after the intervention as compared to baseline. The observed slight changes were not of concern in terms of patient safety. Baseline values varied between patients but to a minor extent. In the passive phase of physiotherapy without WBV, diastolic blood pressure was significantly increased compared to the baseline values (by approx. 2 mmHg; p = 0.014), which was not observed in the WBV training phase, as well as early or late rest. Heart rate, mean arterial pressure, systolic blood pressure, and oxygen saturation did not differ significantly from baseline values during physical therapy without WBV, WBV exercise, or during rest.

Intracranial pressure

Out of 19 patients, 7 had extraventricular fluid drainage to measure intracranial pressure. In line with previous studies, both physiotherapy without WBV and WBV exercises did not significantly affect the level of intracranial pressure.

Hemodynamics – the study of the dynamics of blood flow

The haemodynamic parameters were measured with the PiCCO2 Medical-System in a total of 15 patients. The interventions had no significant effect on the CO, MSV mean, and its scope. These parameters also remained stable during rest. The variability of MSV increased significantly in the phase of physiotherapy without WBV (p <0.001), but it did not change significantly under the influence of WBV or in the rest phases, compared to the baseline state.

Energy metabolism

Indirect calorimetry in 16 patients showed increased energy expenditure only during WBV. Compared to the baseline, the levels of oxygen uptake (by approx. 30 ml/min; p = 0.012) and carbon dioxide production (by approx. 20 ml/min; p <0.001) were increased in the WBV training phase, showing an increased energy expenditure (about 200 kcal/24h; p = 0.007). On the other hand, physiotherapy without WBV led to increased elimination of carbon dioxide (by approx. 10 ml/min; p = 0.041), but not to increased oxygen consumption or increased energy expenditure. In the early and late phase of rest, oxygen uptake and energy expenditure returned to baseline values. The carbon dioxide elimination remained increased in the early phase of rest (by about 6 ml/min; p <0.01) and reached basal levels only in the late phase of rest. Physiotherapy without WBV and WBV training significantly increased the respiratory rate compared to the baseline value, by about 1.5 (p <0.01) or about 1.8 (p <0.001) breaths per minute, respectively. During physiotherapy without WBV, the respiratory rate increased significantly (by approx. 0.03; p = 0.033), which was caused by the increased elimination of carbon dioxide in this phase.

Blood analysis

Blood gas analysis (n = 19) showed that patients’ ventilation remained stable throughout the study, as indicated by unchanging pO2 and pCO2 values, acid-base status and pulse oximetry. WBV training was associated with a significant increase (by approx. 0.05 mmol/l; p = 0.048) in serum potassium compared with the baseline values. This effect was not observed during the physiotherapy phase without WBV. Sodium concentrations in the same blood samples remained unchanged, indicating no sampling errors. Moreover, no changes in glucose and lactate levels were expected. Measurement of IGF-1 and cortisol levels resulted in a wide range of baseline values which may have contributed to the fact that no significant changes were observed.

Comment

The weakness acquired by ICU patients is a frequent and significant complication. It is associated with lowering the synthesis of muscle proteins, their increased degradation, extending the treatment period, and increasing the risk of complications and mortality. It has been noticed that the earlier mobilization of conscious patients allows to shorten the use of mechanical ventilation and the time spent in the ICU (as well as in other hospital wards), and also helps to regain greater functional independence upon discharge from the hospital.

WBV training is known to be effective yet passive physical training for the muscles and can be an option in the fight against muscle weakness and loss. This form of physiotherapy should be particularly desired by immobilized patients for whom active physical exercise is not available {it may also be important in COVID-19 therapy/ rehabilitation [Sañudo et al., 2020]; editorial note}. WBV is used so far to counteract muscle atrophy (mass wasting) and loss of bone density occurring in the absence of gravity in space, moreover it is used as a training for professional athletes, as well as in patients with various diseases.

The presented study shows that WBV training can be safely used even in critically ill patients undergoing mechanical ventilation.

WBV is a powerful stimulus for skeletal muscle, leading to the physiological adaptation of bones and muscles for growth. In previous clinical studies, WBV has been shown to improve mean speed, mean strength, and mean power in healthy volunteers. Depending on the frequency of the vibration stimulus, WBV can induce more than 1,000 muscle contractions per min, which can lead to an increase in muscle strength and mass. Such muscle activation would be expected for ICU patients.

The results of the report show that passive physiotherapy without WBV increased the excretion of carbon dioxide. This can be explained by the mobilization of resting blood in capacity vessels during passive exercise. The lack of active muscle contraction during passive mobilization was reflected by the lack of increase in oxygen uptake. On the other hand, WBVs increased both carbon dioxide excretion and oxygen uptake. This effect of WBV has also been shown in other studies in overweight and obese women.

The levels of pO2, pCO2, pH, HCO3- and the excess of bases, maintained at a constant level with increased energy expenditure, indicate that there is no dysregulation of metabolism, and its increase during the WBV training phase is most likely due to muscle activation. Moreover, serum potassium concentration was significantly elevated only during WBV training and probably due to muscle contraction, which could be confirmed by unchanged serum sodium level. In addition, previous molecular studies show the beneficial effect of in vivo and in vitro vibration on isolated stem cells, myoblasts and muscle tissue. These findings suggest that vibration may have a significant effect on muscle maintenance and in consequence alleviate the development of weakness acquired by ICU patients.

CONCLUSIONS

Taking into account absolute contraindications, the authors of the report conclude that the use of WBV in critically ill patients is a safe and feasible form of physiotherapy. The results obtained confirm the ability of WBV to stimulate muscles and improve their metabolism during immobilization resulting from critical illness, when patients cannot participate in active physiotherapy whether due to sedation or loss of consciousness due to neurological reasons. WBV therefore has the potential to prevent and/ or treat muscle weakness in critically ill patients. Additionally, WBV may be an option of rehabilitation throughout the ICU stay and may be continued after regaining consciousness.

{The presented results suggest the need for further clinical trials to investigate the beneficial effects of vibrotherapy on recuperation also in other hospital wards and also in relation to the COVID-19 pandemic, paralyzing the work of healthcare. Reducing the time spent by covid patients in hospital wards, including ICUs, seems to be extremely important in the fight against COVID-19 [Sañudo et al., 2020]. Editorial note.}

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