PREDICTORS OF SPONTANEOUS PNEUMOMEDIASTINUM IN PATIENTS WITH COVID-19 AND ARDS ON HIGH-FLOW NASAL CANNULA

ABSTRACT

SESSION TITLE ECMO and ARDS in COVID-19 Infections SESSION TYPE Rapid Fire Original Inv PRESENTED ON 10/17/2022 1215 pm - 115 pm PURPOSE: High Flow Nasal Cannula (HFNC) is a non-invasive ventilation (NIV) device widely used to manage hypoxemic respiratory failure. Data about optimal flow rate and time length for safety is lacking. Cases of spontaneous pneumomediastinum (SP) during HFNC oxygen therapy in COVID-19 patients have been recently reported. A study in airway models suggests a non-linear increase in PEEP up to 10 cmH2O in adults on maximum tested flows. Prolonged use of NIV could also delay escalation to invasive ventilation and use of lung-protective volumes (LPV). The ROX-index is a predictive tool for NIV failure and continuous evaluation of intubation indications. This study aimed to identify risk factors associated with the development of SP in COVID-19 ARDS on HFNC support and establish mitigating behavior that will aid in safer COVID-19 treatment modalities. METHODS: Cases from 2020 to 2022 were reviewed. Patients with SP while on HFNC were included as cases. Age and gender-matched patients who received HFNC and did not develop SP were controls. Baseline characteristics between groups were compared using t-test for continuous variables and chi-square for categorical values. Longitudinal ROX scores were calculated until the last day (day of pneumomediastinum development for SP group, and death or MV commencement for controls). Nominal logistic regression was performed to identify variables associated with SP development. Parameter Estimates were used to construct a prediction model, and a ROC curve was implemented to assess the accuracy of the prediction of SP events. RESULTS: Total 61 patients enrolled, 52% (32/61) developed SP on HFNC and 48% (29/61) were control group (CG). No statistical significance found on baseline demographics. Median HFNC days-to-SP was 7 [standard deviation (SD), 6.8 days]. Median days from COVID-19 diagnosis-to-SP was 9 (SD, 5 days). Use of MV was greater in SP group (29 vs 3, p-value < 0.001) and use of vassopresor support (28 vs 3, p-value < 0.001). SP-group had an increased mortality compared to CG, with 88% (28/32) vs.12% (3) (p-value, <0.001). Median ROX scores on Day 1 were 5.45 for SP group and 18.2 for CG (p<0.001). Median ROX scores on last day (day-to-event) were 4.08 and 9.4 in CG (p<0.001). Nominal logistic regression identified number of days on HFNC, ROX score on day 1, and cumulative amount of Flow rate, as independent variables associated with SP development. ROC of the Prediction model using parameter estimates from these 3 variables had an AUC of 0.922. CONCLUSIONS: Development of SP is associated with increased mortality. Patients with lower ROX scores at initiation of therapy, prolonged days of HFNC and increased cumulative flow rates are associated with the development of SP. CLINICAL IMPLICATIONS HFNC has the potential to cause alveolar damage, however a larger patient population size is needed to further analyze the relationship of HFNC use and the development of SP. DISCLOSURES No relevant relationships by Sofia Durscki Vianna No relevant relationships by Cynthia Espinosa No relevant relationships by Hernando Garcia No relevant relationships by Ephraim Mansour No relevant relationships by Laura Mendez Morente No relevant relationships by Zuleikha Muzaffarr No relevant relationships by Sergio Poli No relevant relationships by Luisa Quesada No relevant relationships by Douglas Salguero No relevant relationships by Michelle Yousefzadeh