Daily Ards Research Analysis

OBJECTIVES: There are no established criteria to define the resolution of acute respiratory distress syndrome (ARDS). We aimed to develop an expert consensus definition of ARDS resolution. DESIGN: Modified Delphi consensus study with three iterative rounds. SETTING: Electronic surveys. SUBJECTS: A panel of 19 ARDS experts participated in the Delphi process. Experts were identified using prespecified criteria. INTERVENTIONS: The Delphi process was conducted over three rounds. Item generation was performed in round 1 with all panelists invited to suggest defining characteristics for resolution of ARDS with corresponding operational definitions, which were then voted on by the panel. Item refinement in rounds 2 and 3. Thresholds for agreement were specified a priori and set at 70%. MEASUREMENTS AND MAIN RESULTS: Nineteen panelists submitted complete responses to the first round with 16 panelists contributing to the final definition that met a priori consensus criteria after the third round questionnaire. The panel agreed on the following elements: 1) resolution of hypoxemia, defined as ratio of Pao2/Fio2 greater than 300 (or ratio of oxygen saturation to Fio2 > 315) for more than 24 hours and 2) normalization of level of respiratory support, defined as "if still intubated, this is for primarily nonrespiratory reasons (e.g. altered mental state, ICU-acquired weakness) and ventilatory assistance is minimal (i.e., positive end-expiratory pressure less than or equal to 5 cm H2O, and no adjunctive interventions); if maximal respiratory support was continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV), then no longer requiring CPAP or NIV; if maximal respiratory support was oxygen via high-flow nasal cannula (HFNC), then no longer requiring HFNC; and if maximal respiratory support was standard oxygen, then longer receiving oxygen." CONCLUSIONS: A high level of consensus was achieved on criteria defining the resolution of ARDS. Future work is required to explore the epidemiology and performance characteristics of this definition.

Background Surfactant therapy is performed in different manners in respiratory distress syndrome. Surfactant therapy in spontaneously breathing infants <28weeks' gestation (LIST/MIST) was compared to intubation with different periods of mechanical ventilation (MV/intubation; INSURE) for efficacy and safety. Methods This systematic review and meta-analysis followed PRISMA guidelines with PROSPERO registration (CRD42025630748) using GRADE recommendations. Primary outcomes were BPD at 36weeks' postmenstrual age, MV in first 72hours; and death before discharge. Secondary outcomes were IVH, NEC, ROP, PVL, and pneumothorax. Results No RCT compared directly LISA/MIST versus INSURE in infants <28weeks. Twenty-six studies in the qualitative synthesis and 12 studies in quantitative analysis were included. LISA/MIST compared to INSURE was not different in BPD; or death; but reduced MV within 72hours (RR,0.70;95%CI,0.55-0.90; events/n=58/153; INSURE events/n=82/144). This effect was not detectable when only RCTs were analysed. Compared to intubation, LISA/MIST reduced BPD (RR,0.76; 95% CI,0.59-0.97, n=6585), MV (RR,0.61; 95% CI,0.45-0.82,n=6197), death (RR,0.63;95% CI,0.54-0.74, n=6597), IVH (RR,0.62;95% CI,0.54-0.73), pneumothorax (RR,0.58; 95% CI,0.46-0.73), and ROP (RR,0.61;95% CI,0.50-0.73). Composite outcome analysis BPD/ death was impossible due to small numbers. Discussion/Conclusion LISA/MIST reduced MV, but not either BPD, or separately- death when compared with INSURE. The findings should be interpreted cautiously due to limited power and competing risk dynamics in extremely preterm infants.

HEADINGS: The effects of high-flow nasal cannula (HFNC) and continuous positive airway pressure (CPAP) in patients with acute hypoxemic respiratory failure (AHRF) on respiratory mechanics and inspiratory efforts are not entirely understood. OBJECTIVES: To compare the physiologic effects of HFNC and helmet CPAP with respect to conventional oxygen therapy (COT) in terms of respiratory mechanics, inspiratory effort, gas exchange, and hemodynamics during AHRF. DESIGN: Crossover study. SETTING: General surgical-medical ICU of San Paolo University Hospital, Milan, Italy. PATIENTS: Thirty-three adult patients with AHRF, defined as an Pao2 less than 60 mm Hg or an Pao2/Fio2 less than 300 with a positive end-expiratory pressure (PEEP) level greater than or equal to 5 cm H2O, along with an Paco2 less than 45 mm Hg. INTERVENTIONS: After support with COT, three types of respiratory support were applied in random order: HFNC with 60 L/min of flow and helmet CPAP with 5 or 10 cm H2O of PEEP. MEASUREMENTS AND MAIN RESULTS: Tidal volume, respiratory rate, inspiratory esophageal (ΔPes), and airway pressure swings were measured and an arterial blood gas analysis, along with hemodynamic data, was obtained after 20 minutes from the application of each respiratory support device. The application of HFNC and helmet CPAP at both 5 and 10 cm H2O of PEEP reduced minute ventilation (9.2 ± 3.2, 8.8 ± 2.3, and 9.3 ± 2.7 vs. 10.9 ± 3.3 L/min; p < 0.001) and ΔPes (-6.0 cm H2O [-7.8 to -4.0 cm H2O], -5.8 cm H2O [-7.2 to -4.5 cm H2O], and -5.9 cm H2O [-8.0 to -4.0 cm H2O] vs. -7.5 cm H2O [-10.8 to -6.5 cm H2O]; p < 0.001) while increasing Pao2/Fio2 (188 ± 57, 208 ± 62, and 213 ± 69 vs. 129 ± 32; p < 0.001) with respect to COT; the application of 10 cm H2O of PEEP with helmet CPAP did not reduce inspiratory effort indices or increased oxygenation, but worsened mechanical power compared with HFNC and helmet CPAP with 5 cm H2O of PEEP. CONCLUSIONS: In patients with mild and moderate AHRF, HFNC and helmet CPAP ameliorated minute ventilation and respiratory rate, reduced inspiratory effort, and increased oxygenation compared with COT; the application of 10 cm H2O of PEEP during CPAP support worsened mechanical power.