Análise termográfica em dois modos ventilatórios e efeitos adversos agudos em voluntários sadios após uso de ventilação não invasiva

Abstract

Mechanical Ventilation (MV) replaces all or part of spontaneous ventilation, as it enables improved gas exchange and decreased work of breathing, which can be used non-invasively through an external interface. The success of the Non-Invasive Ventilation (NIV) is dependent on the comfort and acceptance of the mask by the patient. However, the use of masks is associated with adverse acute effects and discomfort. The hypotheses of this study are: variables related to NIV have repercussions on the local microcirculation of the skin in the contact zones with the mask, changing the temperature levels of skin tissue on the face in the contact zones with the oronasal mask. These possible temperature changes in the contact areas are amenable to measurement by infrared thermography and can relate to the acute adverse effects. Objectives: To compare the incidence and intensity of acute adverse effects, and the variation in skin temperature of the ventilation modes of NIV: CPAP versus double level pressure and analyze the relationship between the acute adverse effects of the application of NIV by oronasal mask and temperature variations of the skin face into two regions: the contact zones of the mask and, in particular, the nasal dorsum. Methods: 20 healthy volunteers, both genders that after dermatologic evaluation were submitted to NIV with mask oronasal for an hour, randomly assigned to groups according to the ventilation mode CPAP (continuous positive airway pressure) or double level pressure (two pressure levels, the highest in the inspiration). The infrared thermography image was performed in two distinct regions in the face region and at different times. Participants answered a questionnaire about the adverse effects noted during the NIV. Results: The incidence and intensity of acute adverse effects were higher in double level pressure ventilation mode in relation to CPAP (16.1% versus 5.6%, p=0.001). Thermographic analysis has evidenced a cooling in the contact area with the skin of the face (p<0.05) and nasal dorsum (p<0.05) immediately after the withdrawal of NIV. Acute adverse effects at higher intensity occurred predominantly in the group of participants where the reduction in the average temperature was lower (14.4% versus 7.2%, p=0.04) in the nasal dorsum. The thermographic visual analysis of cooling and heating areas in the face identified areas of hypoperfusion or reactive hyperemia. Conclusions: Acute adverse effects of the use of NIV showed a higher incidence and intensity in the double level pressure ventilation mode. Regarding the average temperature variation there was no statistically significant difference between the ventilation modes. It showed a significant cooling of the skin in the contact area of the mask and the nasal dorsum immediately after the withdrawal of the interface, probably due to the reduction of local perfusion. It was noted the phenomenon of reactive hyperemia in the subsequent moments in the mask contact area, but in the nasal dorsum, the cooling of the region has remained. There was an association between acute adverse effects of the application of NIV by oronasal mask to a lower cooling or increased reactive hyperemia in the nasal dorsum region after the withdrawal of the interface.