| Abstract [eng] |
Aim. To assess the work of breathing of spontaneously breathing critically ill patients with respiratory failure using one conventional and three non-invasive methods and to establish a connection between these assessment methods. Materials and methods. Spontaneously breathing critically ill patients treated in the intensive care unit and diagnosed with acute hypoxemic respiratory failure were included in this prospective study. Respiratory effort was assessed using an invasive method – an esophageal balloon – and three non-invasive methods: bioimpedance-based respiratory volume monitoring, diaphragmatic ultrasound and a thoracic cage excursion force belt. Measurements were performed synchronously at 0, 5 and 10 minutes. Results. 13 patients were included in the study, with a mean age of 69.0 ± 8.0 years, a mean SOFA score of 5.1 ± 2.5, and an APACHE II score of 14.6 [9.9–24.0]. The median PaO2/FiO2 ratio was 202 [105–271]. The esophageal pressure measured with an esophageal balloon before inspiration was 10.43 [3.93–18.03] cmH2O, the maximal inspiratory pressure was 0.49 [-5.21–8.57] cmH2O and the mean inspiratory pressure-time product was 5.25 ± 4.98 cmH2O · s. The mean tidal volume measured by tidal volume monitoring was 409.13 ± 140.19 ml, the respiratory rate was 25.78 breaths/min, and the median minute ventilation was 146.33 [130.50–165.33] % of the predicted value. During diaphragm ultrasound examination, the median right diaphragm thickening fraction was 29.0 [22.0–42.0] % and the median left diaphragm thickening fraction was 39.5 [29.0–57.5] %. The mean inspiratory force determined by the thoracic cage excursion force belt was 1.13 ± 0.57 N, the maximal inspiratory force was 2.46 ± 1.14 N, and the mean inspiratory Newton-time product was 0.33 ± 1.03 N · s. Conclusions. Critically ill patients included in this study had mild to moderate hypoxemic respiratory failure and relatively low to moderate respiratory effort. Non-invasive methods enabled real-time assessment of different aspects of respiratory effort and may be used as additional monitoring tools. Due to the small sample size, statistically reliable associations between invasive and non-invasive methods could not be established. |
