Respiratory physiotherapy with vibration belts in the critical patient Covid-19 in the prone position

To the Editor:

The current pandemic has led to an exponential increase in the need for invasive mechanical ventilation in patients with acute respiratory distress syndrome.

When lung protection and oxygenation targets are not achieved, patients are ventilated in the prone position¹ to improve ventilation/perfusion of the alveoli. The lung and alveolar epithelium damage caused by the infection, together with the immune reaction and the cytokine storm, increase alveolar secretions, preventing adequate gas exchange in the undamaged alveoli. There is an increased risk of severe atelectasis secondary to the production of mucus plugs that completely obstruct the bronchial lumen. Various manual respiratory physiotherapy techniques for patients with respiratory distress have been described in the literature. In the case of the COVID-19 pandemic, it is important to ensure that the patient receives the best possible treatment while minimizing the risk of exposure and contact with patients in contaminated areas and reducing the number of people who care for the patient to the absolute minimum. With this objective in mind, we present a series of patients with pneumonia and invasive mechanical ventilation who were placed in the prone position to undergo mobilization of secretions using an autonomous vibratory belt system.

Our objective was to determine whether this would improve ventilator-delivered arterial oxygen partial pressure to fractional inspired oxygen ratio (PAO₂/FIO₂). PAO₂/FIO₂ was measured at 3 time points: PAO₂/FIO₂ supine, PAO₂/FIO₂ after 2 h prone, and PAO₂/FIO₂ in the prone position after performing respiratory physiotherapy with an autonomous vibrating belt.

Compassionate use was authorized by the hospitals Research Committee, and the family's authorization and informed consent was obtained verbally and by telephone. A standard vibrating belt (Innovagoods, Sauna effect model, 2019, Valencia, Spain) was used. The belt has various speeds, and for these patients the lowest speed (equivalent to 8 hz) was used, without heat. This minimal vibration is similar to that of full torso belts^2,3 that have been used for several years. The physiotherapy belt was placed on the back and lower part of the thorax in order to facilitate mobilization of secretions from the areas of greater decubitus where they are more likely to accumulate.^4,5

The belt also has two lateral fabric extensions that allow it to be secured to prevent it from moving during use. The fabric extensions are only used to secure the belt and do not exert any pressure on the patient in order to avoid pressure injuries. The device was placed over the lower posterior thorax two hours after placing the patient in the prone position. Three 15-minute lung physiotherapy sessions were performed, each with the vibrating belt at the lowest vibration speed without local heat.

Each 15-minute physiotherapy session was followed by an hour of rest before the next session. After completing the 3 sessions, and 4 h after the start of respiratory physiotherapy, PAO₂/FIO₂ was measured.

Ten patients were studied immediately after prone positioning, with a total of 15 pronations, observing improvement in 12 (Table 1). Mean PAO₂/FIO_2o in supine was 114.86 (17.25), in prone it was 144.73 (36.04) and in prone plus physiotherapy it was 162.66 (35.57). An improvement in PAO₂/FIO₂ was observed in most respiratory physiotherapy interventions, especially in those patients who responded to prone positioning.

Table 1.

PAO₂/FIO₂ measurements in the supine, prone, and prone position plus respiratory physiotherapy.

Patient	PaO2/FiO2 1 Pre-prone	PaO2/FiO2 2 Post-prone	PaO2/FiO2 3 - Post-prone + Belt
Patient 1 prone 1	117	143	186
Patient 1 prone 2	150	156	192
Patient 1 prone 3	101	108	112
Patient 2 prone 1	125	141	175
Patient 2 prone 2	124	146	151
Patient 3 prone 1	128	187	207
Patient 4 prone 1	105	162	148
Patient 5 prone 1	75	80	165
Patient 6 prone 1	116	230	240
Patient 7 prone 1	105	106	118
Patient 7 prone 2	130	136	109
Patient 8 prone 1	104	103	132
Patient 9 prone 1	103	178	148
Patient 9 prone 2	125	149	175
Patient 10 prone 1	80	146	182
Mean PaO2/FiO2	114.86 (17.25)	144.73 (36.04)	162.66 (35.57)

Changing position from supine to prone may facilitate an improvement in PAO₂/FIO₂ due to the change in pulmonary perfusion ventilation and mobilization of secretions. Facilitating mobilization and expulsion of secretions with mechanical systems could reduce pulmonary atelectasis and facilitate alveoli ventilation by preventing the formation of mucus plugs that obstruct the bronchioles and improving PAO₂/FIO₂.

More studies are required to confirm the advantages of respiratory physiotherapy with autonomous vibration belts in critically ill, mechanically ventilated patients with COVID-19 infection placed in the prone position (Fig. 1).

Figure 1.

Definitive placement of the autonomous vibratory belt in critically ill patients with COVID-19 infection in the prone position.