Drive ed effort respiratorio in pazienti con ARDS associata a COVID-19: uno studio multicentrico prospettico osservazionale

INTRODUCTION Monitoring respiratory drive and effort can be useful in critically ill patients under spontaneous assisted breathing to prevent respiratory muscle atrophy and patient self induced lung injury. Acute respiratory distress syndrome (ARDS) commonly causes increased respiratory drive and effort. In COVID-19 related ARDS (CARDS), respiratory drive and effort may be even higher, leading to relapse of acute respiratory failure and worse outcomes. Therefore, further research comparing CARDS and ARDS patients is needed to highlight differences in respiratory drive and effort and their impact on clinical outcomes. OBJECTIVES First aim was to investigate the changes in respiratory drive and effort using neurally-adjusted ventilatory assist (NAVA) catheter in CARDS patients compared to ARDS patients. The second aim was to evaluate the incidence of composite outcome of transition from light to deep sedation (Richmond Agitation-Sedation Scale, RASS from 0/-2 to -4/-5) or from assisted to controlled ventilation within 48 hours from spontaneous assisted breathing. METHODS This multicenter study was conducted in four ICUs in Italy and prospectively recruited patients with CARDS, comparing them to a historical cohort of patients with ARDS. All patients who transitioned from controlled ventilation to assisted ventilation and had a RASS level of 0/-2 were included. The CARDS cohort was divided into 'mild' and 'severe' COVID-19 groups according to P/F ratio at ICU admission. Respiratory mechanics variables were recorded for 90 consecutive breaths and 2 end-expiratory occlusions were performed to measure Pmusc/Eadi index (PEI). The study protocol included the assessment of respiratory drive using P0.1vent, and respiratory effort using NAVA catheter (∆Edi, PmusEdi). Inspiratory pressures in pressure support mode were kept at 10 cmH2O for all patients. RESULTS We enrolled 55 patients (10 severe-COVID19, 7 mild-COVID19, and 38 non-COVID19 patients) and analyzed a total of 4301 breaths. Baseline characteristics were reported in table 1. P0.1vent was found to be significantly different between the three groups (Figure 1). Respiratory effort (∆Edi, PmusEdi) was markedly different between severe-COVID19 and the other two groups (Figure 1). Within the cohort of severe-COVID19 patients, 70% underwent a transition from assisted to controlled ventilation or from a RASS score of 0/-2 to -4/-5. None of the patients in the mild-COVID19 cohort required such a transition, while 2.6% of the non-COVID-19 cohort experienced this shift. CONCLUSIONS In severe-COVID19 patients, respiratory drive and effort are markedly altered. Our findings highlight significant differences in clinical outcomes, ventilation duration, ICU mortality, and ICU length of stay among patients with severe CARDS. These results suggest that greater caution should be exercised in implementing spontaneous mechanical ventilation strategies in CARDS patients

INTRODUZIONE La sindrome da distress respiratorio acuto (ARDS) può causare un aumento del drive e dell’effort respiratorio. Non è noto se la ARDS correlata al COVID-19 (CARDS) induca un maggiore drive ed effort respiratorio rispetto alla ARDS. Obiettivo dello studio è di quantificare il drive ed effort respiratorio in pazienti con CARDS e determinare l’insuccesso nella transizione dalla ventilazione controllata ad assistita entro 48 ore. METODI Sono stati inclusi pazienti adulti con CARDS e con ARDS. I pazienti con CARDS sono stati categorizzati in ‘Moderato’ e ‘Severo’ in base al rapporto PaO2/FiO2 (<100). Sono state scelte soglie di valori non sicuri di drive respiratorio, P0.1 (> 3.5 cmH2O o < 1 cmH2O), di attività elettrica del diaframma, EAdiPEAK (> 15 µV o < 5 µV), di effort respiratorio ∆PmusEAdi o ∆Pmus∆Pocc (>15 cmH2O), di pressione transpolmonare dinamica, ΔPL,dyn (>15 cmH2O), e di pressure time product, PTP/min (>150 cmH2O /s/min o < 50 cmH2O/s/min). Il fallimento è stato definito come il passaggio da uno stato di sedazione leggera a sedazione profonda (scala RASS da 0/-3 a -4/-5) o il passaggio da ventilazione assistita a controllata. Sono stati applicati il generalized estimating equation model e il modello di Cox. RISULTATI Abbiamo analizzato 4171 atti respiratori di 56 pazienti. Rispetto ai Non-COVID-19 e COVID-19 moderato, i pazienti con COVID-19 grave avevano un maggiore drive ed effort respiratorio: P0.1 (0.67 e 0.95 vs 2.67 cmH2O), PmusEAdi (6.62 e 6.96 vs 15.93 cmH2O), PmusΔPocc (6 e 7 vs 12 cmH2O), ΔPL,dyn (15.04 e 15.32 vs 20.73 cmH2O), e PTP/min (77 e 95 vs 230 cmH2O/s/min), rispettivamente. Il rischio di fallimento dalla transizione dalla ventilazione assistita alla controllata a 48 ore era 10.1 volte più alto (95% confidence interval, CI 2.09-48.7) nei pazienti con COVID-19 grave. Dopo aver aggiustato il modello per confondenti, il rischio è sceso a 5.04 (95% CI 0.8-32.0). CONCLUSIONI I pazienti con CARDS presentano drive ed effort respiratorio e pressione transpolmonare elevati. Fattori di rischio indipendenti per il ripristino alla ventilazione controllata sono la gravità del COVID-19, il rapporto PaO2/FiO2, i giorni di sedazione e la dose di steroidi prima della ventilazione.