Daily Ards Research Analysis
Analyzed 12 papers and selected 3 impactful papers.
Summary
A randomized clinical trial in preterm infants with neonatal ARDS found that elective HFOV reduced bronchopulmonary dysplasia versus conventional ventilation without increasing adverse events. A prospective physiologic study showed inspiratory rise time has opposite effects on mechanical power in pressure- versus volume-controlled ventilation, informing ventilator-induced lung injury mitigation. A cohort study identified plasma and BALF surfactant protein D as strong prognostic biomarkers for 28-day mortality in ARDS.
Research Themes
- Ventilation strategies for neonatal ARDS
- Mechanical power and ventilator-induced lung injury mechanics
- Biomarker-based risk stratification in ARDS
Selected Articles
1. High-Frequency Oscillation vs Mechanical Ventilation for Neonatal Acute Respiratory Distress Syndrome: A Randomized Clinical Trial.
In a single-center RCT of 386 preterm infants with NARDS, elective HFOV reduced bronchopulmonary dysplasia compared with continued CMV under two accepted BPD definitions, without increasing mortality or major neonatal complications. Findings support HFOV as a preventive strategy for BPD in high-risk preterm NARDS.
Impact: This well-powered, registered RCT directly informs first-line ventilatory strategy in neonatal ARDS and demonstrates clinically meaningful reductions in BPD without safety trade-offs.
Clinical Implications: For preterm infants with NARDS stabilized on CMV, early transition to elective HFOV may reduce BPD risk. Implementation should consider center expertise and await multicenter confirmation before broad guideline changes.
Key Findings
- HFOV reduced BPD versus CMV: 34.3% vs 44.9% (NICHD 2001 definition; RR 0.92, 95% CI 0.86-0.99).
- HFOV reduced BPD under 2019 definition: 17.1% vs 25.4% (RR 0.68, 95% CI 0.45-1.00).
- No significant differences in mortality, severe ROP, NEC ≥ stage 2, IVH ≥ grade 3, air leak, or hsPDA.
- Sensitivity analysis excluding 44 crossovers yielded consistent estimates.
Methodological Strengths
- Prospective randomized allocation with prespecified primary outcomes and trial registration (NCT03591796).
- Robust statistical approaches (modified Poisson, ordinal, Cox regression) and adequate sample size (n=386).
Limitations
- Single-center design may limit generalizability.
- Potential lack of blinding and treatment crossovers could introduce bias.
- BPD definition heterogeneity complicates cross-study comparisons.
Future Directions: Multicenter RCTs comparing HFOV-first strategies with standardized protocols and long-term neurodevelopmental follow-up are needed to confirm generalizability and inform guidelines.
IMPORTANCE: Key clinical features of neonatal acute respiratory distress syndrome (NARDS) are broadly comparable to those observed in pediatric and adult ARDS; however, evidence is insufficient to recommend high-frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CMV) as the preferred first-line therapy. OBJECTIVE: To evaluate whether HFOV is superior to CMV in reducing bronchopulmonary dysplasia (BPD) and other neonatal adverse outcomes, including death, among preterm infants (≤34 weeks' gestational age) with NARDS. DESIGN, SETTING, AND PARTICIPANTS: This single-center randomized clinical trial conducted from August 1, 2019, to December 31, 2023, enrolled preterm infants born between 25 weeks 0 days and 34 weeks 6 days of gestation with NARDS who were stabilized with CMV. Data were analyzed from October to December 2024. INTERVENTION: Participants were randomly assigned to continue CMV or transition to elective HFOV. MAIN OUTCOMES AND MEASURES: The primary outcome was BPD, assessed using 2 definitions: definition 1, that of the 2001 Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and definition 2, one based on 2019 research. Secondary outcomes included death, retinopathy of prematurity (higher than stage 2), necrotizing enterocolitis (stage 2 or higher), intraventricular hemorrhage (grade 3 or higher), air leak, and hemodynamically significant patent ductus arteriosus. Modified Poisson regression, ordinal regression, and Cox proportional hazards regression were applied for outcome risk assessment where applicable. RESULTS: A total of 386 preterm infants (230 male [59.6%]; mean [SD] maternal age, 29.9 [4.8] years) were randomized: 181 to elective HFOV and 205 to CMV. Overall, 154 (39.9%) and 83 (21.5%) developed BPD according definitions 1 and 2, respectively. Elective HFOV reduced the risk of BPD by 8.0% (34.3% vs 44.9%; relative risk, 0.92; 95% CI, 0.86-0.99) according to definition 1 and by 32.0% (17.1% vs 25.4%; relative risk 0.68; 95% CI, 0.45-1.00) according to definition 2 compared with CMV. No significant between-group differences were observed for death, higher than stage 2 retinopathy of prematurity, stage 2 or higher necrotizing enterocolitis, grade 3 or higher intraventricular hemorrhage, air leak, or hemodynamically significant patent ductus arteriosus. Sensitivity analysis excluding 44 participants who crossed over between treatment groups did not significantly attenuate the estimates. CONCLUSIONS AND RELEVANCE: This randomized clinical trial found that elective HFOV reduced the incidence of BPD in preterm infants born at 34 weeks' gestation or earlier with NARDS compared with CMV. The results of this study suggest that elective HFOV is a promising strategy for preventing BPD in this high-risk population, especially the more severe forms linked to increased long-term morbidity and mortality. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03591796.
2. Adjusting inspiratory rise time alters mechanical power in acute respiratory distress syndrome: opposing effects in pressure-controlled and volume-controlled ventilation modes.
In 30 ARDS patients, increasing inspiratory rise time from 5% to 15% raised geometric mechanical power in VCV but reduced it in PCV by over 1 J/min. Changing I:E from 1:2 to 1:1 reduced MP in VCV and had minimal effect in PCV, suggesting mode-specific strategies to minimize VILI.
Impact: Provides actionable, mode-specific physiologic insights on inspiratory rise time and mechanical power using a within-patient design and geometric analysis, directly informing ventilator setting optimization.
Clinical Implications: When targeting lower mechanical power, consider lengthening rise time in PCV and avoiding excessive rise time in VCV; increasing I:E to 1:1 may reduce MP in VCV. These adjustments could help mitigate ventilator-induced lung injury pending outcome-validation.
Key Findings
- In VCV, increasing Tslope from 5% to 15% increased MPtotal; raising I:E from 1:2 to 1:1 reduced MP.
- In PCV, increasing Tslope from 5% to 15% decreased MPtotal by >1 J/min; I:E changes had minimal effect.
- No intrinsic PEEP was detected across settings, isolating Tslope/I:E effects on MP.
Methodological Strengths
- Prospective within-patient crossover assessment in both VCV and PCV modes.
- Use of geometric mechanical power from P–V loops with standardized ventilator platform.
Limitations
- Small, single-center physiologic study without clinical outcome measures.
- Deep sedation and paralysis may limit generalizability to spontaneously breathing patients.
Future Directions: Randomized trials testing rise-time–guided protocols targeting mechanical power with patient-centered outcomes (VILI, ventilator days, mortality) are warranted.
BACKGROUND: Mechanical power (MP), a predictor of ventilator-induced lung injury (VILI), is influenced by ventilatory parameters such as inspiratory rise time (Tslope). While Tslope affects the flow profile, its impact on MP in acute respiratory distress syndrome (ARDS) has not been thoroughly studied, particularly using the geometric method. METHODS: In this prospective observational study, 30 deeply sedated and paralyzed ARDS patients were ventilated in both volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) modes using a Maquet Servo-u ventilator. At inspiratory-to-expiratory (I:E) ratios of 1:2 and 1:1, Tslope was adjusted from 5 to 15%, and pressure-volume (P-V) loop screenshots were captured. Geometric mechanical power (MPtotal) was calculated based on the area enclosed by the P-V loops. A total of 720 images were analyzed. RESULTS: In VCV mode, increasing Tslope from 5 to 15% led to a statistically significant increase in MPtotal: 0.8 J/min (5%) at I:E 1:2 and 0.1 J/min (1%) at I:E 1:1. Conversely, in PCV mode, Tslope prolongation resulted in a significant decrease in MPtotal: 1.8 J/min (12.5%) at I:E 1:2 and 1 J/min (7%) at I:E 1:1. No intrinsic PEEP was detected. CONCLUSION: Modifying Tslope alters MPtotal in opposing directions in PCV and VCV modes. In VCV, prolonging Tslope from 5 to 15% increased MP, whereas increasing the I:E ratio from 1:2 to 1:1 reduced MP. In PCV, prolongation of Tslope from 5 to 15% decreased MP by more than 1 J/min, and changes in the I:E ratio exerted minimal effects on MP.
3. Prognostic value of surfactant protein D and biochemical markers in BALF and plasma of ARDS patients undergoing mechanical ventilation.
Among 103 mechanically ventilated ARDS patients, non-survivors had significantly higher SP-D levels in both BALF and plasma. SP-D showed strong prognostic performance (plasma AUC 0.864; BALF AUC 0.804), and a combined biomarker model achieved an AUC of 0.883 for 28-day mortality.
Impact: Identifies a clinically accessible biomarker (plasma SP-D) with strong discrimination for short-term mortality, supporting objective risk stratification in ARDS.
Clinical Implications: Plasma SP-D, alone or combined with lactate and oxygenation indices, may aid early prognostication and triage in ventilated ARDS patients where BALF sampling is impractical.
Key Findings
- Non-survivors had significantly higher SP-D in both BALF and plasma (P<0.001).
- Plasma SP-D (AUC 0.864) and BALF SP-D (AUC 0.804) predicted 28-day mortality.
- Exosome levels did not differ significantly between survivors and non-survivors.
- Combined biomarker model (SP-D, lactate, acid-base/oxygenation indices) achieved AUC 0.883.
Methodological Strengths
- Concurrent assessment of BALF and plasma biomarkers at diagnosis with ROC-based evaluation.
- Defined endpoint (28-day mortality) and inclusion of acid-base and oxygenation covariates.
Limitations
- Single-center cohort with modest sample size limits external validity.
- BALF sampling is invasive; external validation of plasma SP-D cutoffs is needed.
- Single time-point measurement may miss temporal dynamics.
Future Directions: Multicenter validation of plasma SP-D thresholds, integration into prognostic scores, and assessment of biomarker-guided management strategies are warranted.
BACKGROUND: Surfactant protein D (SP-D) and circulating exosomes have emerged as potential biochemical indicators of lung injury severity in acute respiratory distress syndrome (ARDS). This study aimed to evaluate the prognostic value of SP-D levels and selected biochemical parameters in bronchoalveolar lavage fluid (BALF) and plasma among ARDS patients receiving mechanical ventilation. METHODS: A total of 103 mechanically ventilated ARDS patients were enrolled between February 2020 and February 2023. Patients were classified into survival (n = 59) and death (n=44) groups based on 28-day mortality. On the day of diagnosis, SP-D and exosome levels in BALF and plasma, along with pH, lactate, and oxygenation-related indices, were measured and analyzed for prognostic relevance. RESULTS: SP-D levels in both BALF and plasma were significantly higher in non-survivors (P < 0.001), while exosome levels did not differ significantly. The death group also showed elevated lactate and lower pH levels (P< 0.05). ROC analysis demonstrated high predictive value for SP-D in BALF (AuC=0.804) and plasma (AU C= 0.864), as well as for lactate and oxygenation indices. A combined biomarker model yielded an AUC of 0.883 for predicting 28-day mortality. CONCLUSIONS: SP-D concentrations in BALF and plasma, along with lactate and acid-base markers, serve as valuable biochemical predictors of short-term prognosis in ARDS patients undergoing mechanical ventilation. UVOD: Surfaktantski protein D (SP-D) i cirkulišući egzozomi pojavili su se kao potencijalni biohemijski indikatori težine oštećenja pluća kod akutnog respiratornog distresa (ARDS). Cilj ove studije bio je da se proceni prognostička vrednost nivoa SP-D i odabranih biohemijskih parametara u tečnosti bronhoalveolarnog lavaža (BALF) i plazmi kod pacijenata sa ARDS-om koji primaju mehaničku ventilaciju. METODE: Ukupno 103 mehanički ventilirana pacijenta sa ARDS-om su uključena u istraživanje između februara 2020. i februara 2023. godine. Pacijenti su klasifikovani u grupe preživljavanja (n = 59) i smrti (n=44) na osnovu mortaliteta od 28 dana. Na dan dijagnoze, nivoi SP-D i egzozoma u BALF i plazmi, zajedno sa pH, laktatom i indeksima povezanim sa oksigenacijom, mereni su i analizirani na prognostički značaj. REZULTATI: Nivoi SP-D i u BALF i u plazmi bili su značajno viši kod nepreživelih (P< 0,001), dok se nivoi egzozoma nisu značajno razlikovali. Grupa sa smrtnim ishodom je takođe pokazala povišen nivo laktata i niži nivo pH (P< 0,05). ROC analiza je pokazala visoku prediktivnu vrednost za SP-D u BALF (aUc =0,804) i plazmi (AUC = 0,864), kao i za indekse laktata i oksigenacije. Kombinovani model biomarkera dao je AUC od 0,883 za predviđanje mortaliteta u roku od 28 dana. ZAKLJUČAK: Koncentracije SP-D u BALF i plazmi, zajedno sa markerima laktata i acidobazne kiseline, služe kao vredni biohemijski prediktori kratkoročne prognoze kod pacijenata sa ARDS-om koji se podvrgavaju mehaničkoj ventilaciji.