Venovenous Extracorporeal Membrane Oxygenation Initiation for Pediatric Acute Respiratory Distress Syndrome With Cardiovascular Instability is Associated With an Immediate and Sustained Decrease in Vasoactive-Inotropic Scores.

OBJECTIVE: To determine the association of venovenous extracorporeal membrane oxygenation (VV-ECMO) initiation with changes in vasoactive-inotropic scores (VISs) in children with pediatric acute respiratory distress syndrome (PARDS) and cardiovascular instability. DESIGN: Retrospective cohort study. SETTING: Single academic pediatric ECMO center. PATIENTS: Children (1 mo to 18 yr) treated with VV-ECMO (2009-2019) for PARDS with need for vasopressor or inotropic support at ECMO initiation. MEASUREMENTS AND MAIN RESULTS: Arterial blood gas values, VIS, mean airway pressure (mPaw), and oxygen saturation (Sp o2 ) values were recorded hourly relative to the start of ECMO flow for 24 hours pre-VV-ECMO and post-VV-ECMO cannulation. A sharp kink discontinuity regression analysis clustered by patient tested the difference in VISs and regression line slopes immediately surrounding cannulation. Thirty-two patients met inclusion criteria: median age 6.6 years (interquartile range [IQR] 1.5-11.7), 22% immunocompromised, and 75% had pneumonia or sepsis as the cause of PARDS. Pre-ECMO characteristics included: median oxygenation index 45 (IQR 35-58), mPaw 32 cm H 2o (IQR 30-34), 97% on inhaled nitric oxide, and 81% on an advanced mode of ventilation. Median VIS immediately before VV-ECMO cannulation was 13 (IQR 8-25) with an overall increasing VIS trajectory over the hours before cannulation. VISs decreased and the slope of the regression line reversed immediately surrounding the time of cannulation (robust p < 0.0001). There were pre-ECMO to post-ECMO cannulation decreases in mPaw (32 vs 20 cm H 2o , p < 0.001) and arterial P co2 (64.1 vs 50.1 mm Hg, p = 0.007) and increases in arterial pH (7.26 vs 7.38, p = 0.001), arterial base excess (2.5 vs 5.2, p = 0.013), and SpO 2 (91% vs 95%, p = 0.013). CONCLUSIONS: Initiation of VV-ECMO was associated with an immediate and sustained reduction in VIS in PARDS patients with cardiovascular instability. This VIS reduction was associated with decreased mPaw and reduced respiratory and/or metabolic acidosis as well as improved oxygenation.

Alveolar dead space fraction is not associated with early RV systolic dysfunction in pediatric ARDS.

PRIMARY HYPOTHESIS: We hypothesized that higher alveolar dead space fraction (AVDSf) at pediatric acute respiratory distress syndrome (PARDS) onset would be associated with right ventricular (RV) systolic dysfunction within the first 24 h of PARDS. STUDY DESIGN AND METHODS: We performed a retrospective single-center cohort study of PARDS patients with clinically obtained echocardiograms within 24 h. Primary exposure was AVDSf at PARDS onset. Primary outcome was RV systolic dysfunction as defined by RV global longitudinal strain (GLS) (>-18%). Secondary outcomes included pulmonary hypertension (PH) and RV systolic dysfunction as defined by other echocardiogram parameters, and measures of oxygenation. Unadjusted and adjusted logistic and linear regression were used to investigate AVDSf associations with outcomes. RESULTS: Ninety-one patients were included: median age 6.2 years, 46% female, and 65% with moderate or severe PARDS. Median AVDSf was 0.2 (interquartile range [IQR] 0.0-0.3), 33% had RV dysfunction, and 21% had PH. Unadjusted and adjusted logistic regression showed no association between AVDSf and RV systolic dysfunction or PH by any echocardiographic measure, but unadjusted and adjusted linear regression did show an association between AVDSf and PaO2 /FiO2 . CONCLUSION: AVDSf at PARDS onset was not associated with RV systolic dysfunction or PH within 24 h but was associated with PaO2 /FiO2 ratio and may be more reflective of pulmonary causes of ventilation-perfusion mismatch. Future investigations should focus on clarifying the clinical utility of AVDSf in relation to existing metrics throughout the course of PARDS.