Project description:IntroductionAssessment of treatments for acute respiratory distress syndrome (ARDS) has focused on short-term outcomes (for example, mortality); little information exists regarding long-term effects of ARDS treatment. Survivors of ARDS episodes may have long-term obstructive/restrictive pulmonary abnormalities and pulmonary gas exchange impairment. A 2004 prospective randomized placebo-controlled trial assessed the efficacy and safety of inhaled nitric oxide (iNO) in patients with non-septic ARDS; the primary endpoint was days alive and off assisted breathing. This analysis examined potential effects of iNO or placebo on pulmonary function six months post-treatment in ARDS survivors from that original study.MethodsARDS survivors (N = 92) from a large-scale randomized, placebo-controlled study evaluating mortality after either 5 ppm iNO or placebo for up to 28 days were assessed six months post-treatment. Pulmonary function testing across seven parameters was conducted.ResultsAt 6 months post-treatment, results indicated significantly better absolute values for iNO versus placebo for mean ± SD total lung capacity (TLC, 5.54 ± 1.42 vs. 4.81 ± 1.00; P = 0.026). There were also significantly better values for mean ± SD percent predicted values for a) forced expiratory volume in 1 second (FEV1, 80.23 ± 21.21 vs. 69.51 ± 28.97; P = 0.042), b) forced vital capacity (FVC, 83.78 ± 19.37 vs. 69.84 ± 27.40; P = 0.019), c) FEV1/FVC (96.14 ± 13.79 vs. 87.92 ± 19.77; P = 0.033), and d) TLC (93.33 ± 18.21 vs. 76.10 ± 21.84; P < 0.001). Nonsignificant differences were found in absolute FEV1, FEV1/FVC, FVC, forced expiratory flow from 25% to 75% of FVC, functional residual capacity, and CO diffusion.ConclusionsARDS patients surviving after treatment with low-dose iNO had significantly better values for select pulmonary function tests at six months post-treatment than placebo-treated patients. Further trials are warranted to determine the effects of iNO on chronic lung function in ARDS survivors, a factor in long-term morbidity and quality of life in this population.Trial registrationA Double-blind, Randomized, Placebo-controlled, Dose-response Study of Inhaled Nitric Oxide in the Treatment of Acute Respiratory Distress Syndrome. NCT number: ISRCTN53268296.
Project description:ObjectivesLiterature regarding appropriate use of inhaled nitric oxide for pediatric acute respiratory distress syndrome is sparse. This study aims to determine if positive response to inhaled nitric oxide is associated with decreased mortality and duration of mechanical ventilation in pediatric acute respiratory distress syndrome.DesignRetrospective cohort study.SettingLarge pediatric academic medical center.Patients or subjectsOne hundred sixty-one children with pediatric acute respiratory distress syndrome and inhaled nitric oxide exposure for greater than or equal to 1 hour within 3 days of pediatric acute respiratory distress syndrome onset.InterventionsPatients with greater than or equal to 20% improvement in oxygenation index or oxygen saturation index by 6 hours after inhaled nitric oxide initiation were classified as "responders."Measurements and main resultsOxygenation index, oxygen saturation index, and ventilator settings were evaluated prior to inhaled nitric oxide initiation and 1, 6, 12, and 24 hours following inhaled nitric oxide initiation. Primary outcomes were mortality and duration of mechanical ventilation. Baseline characteristics, including severity of illness, were similar between responders and nonresponders. Univariate analysis showed no difference in mortality between responders and nonresponders (21% vs 21%; p = 0.999). Ventilator days were significantly lower in responders (10 vs 16; p < 0.001). Competing risk regression (competing risk of death) confirmed association between inhaled nitric oxide response and successful extubation (subdistribution hazard ratio = 2.11; 95% CI, 1.41-3.17; p < 0.001). Response to inhaled nitric oxide was associated with decreased utilization of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation and lower hospital charges (difference in medians of $424,000).ConclusionsPositive response to inhaled nitric oxide was associated with fewer ventilator days, without change in mortality, potentially via reduced use of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation. Future studies of inhaled nitric oxide for pediatric acute respiratory distress syndrome should stratify based on oxygenation response, given the association with favorable outcomes.
Project description:BackgroundIn COVID-19 patients with severe acute respiratory distress syndrome (ARDS), the relatively preserved respiratory system compliance despite severe hypoxemia, with specific pulmonary vascular dysfunction, suggests a possible hemodynamic mechanism for VA/Q mismatch, as hypoxic vasoconstriction alteration. This study aimed to evaluate the capacity of inhaled nitric oxide (iNO)-almitrine combination to restore oxygenation in severe COVID-19 ARDS (C-ARDS) patients.MethodsWe conducted a monocentric preliminary pilot study in intubated patients with severe C-ARDS. Respiratory mechanics was assessed after a prone session. Then, patients received iNO (10 ppm) alone and in association with almitrine (10 μg/kg/min) during 30 min in each step. Echocardiographic and blood gases measurements were performed at baseline, during iNO alone, and iNO-almitrine combination. The primary endpoint was the variation of oxygenation (PaO2/FiO2 ratio).ResultsTen severe C-ARDS patients were assessed (7 males and 3 females), with a median age of 60 [52-72] years. Combination of iNO and almitrine outperformed iNO alone for oxygenation improvement. The median of PaO2/FiO2 ratio varied from 102 [89-134] mmHg at baseline, to 124 [108-146] mmHg after iNO (p = 0.13) and 180 [132-206] mmHg after iNO and almitrine (p < 0.01). We found no correlation between the increase in oxygenation caused by iNO-almitrine combination and that caused by proning.ConclusionIn this pilot study of severe C-ARDS patients, iNO-almitrine combination was associated with rapid and significant improvement of oxygenation. These findings highlight the role of pulmonary vascular function in COVID-19 pathophysiology.
Project description:ImportanceProne positioning improves clinical outcomes in moderate-to-severe acute respiratory distress syndrome and has been widely adopted for the treatment of patients with acute respiratory distress syndrome due to coronavirus disease 2019. Little is known about the effects of prone positioning among patients with less severe acute respiratory distress syndrome, obesity, or those treated with pulmonary vasodilators.ObjectivesWe characterize the change in oxygenation, respiratory system compliance, and dead-space-to-tidal-volume ratio in response to prone positioning in patients with coronavirus disease 2019 acute respiratory distress syndrome with a range of severities. A subset analysis of patients treated with inhaled nitric oxide and subsequent prone positioning explored the influence of pulmonary vasodilation on the physiology of prone positioning.Design setting and participantsRetrospective cohort study of all consecutively admitted adult patients with acute respiratory distress syndrome due to coronavirus disease 2019 treated with mechanical ventilation and prone positioning in the ICUs of an academic hospital between March 11, 2020, and May 1, 2020.Main outcomes and measuresRespiratory system mechanics and gas exchange during the first episode of prone positioning.ResultsAmong 122 patients, median (interquartile range) age was 60 years (51-71 yr), median body mass index was 31.5 kg/m2 (27-35 kg/m2), and 50 patients (41%) were female. The ratio of Pao2 to Fio2 improved with prone positioning in 90% of patients. Prone positioning was associated with a significant increase in the ratio of Pao2 to Fio2 (from median 149 [123-170] to 226 [169-268], p < 0.001) but no change in dead-space-to-tidal-volume ratio or respiratory system compliance. Supine ratio of Pao2 to Fio2, respiratory system compliance, positive end-expiratory pressure, and body mass index did not correlate with absolute change in the ratio of Pao2 to Fio2 with prone positioning. However, patients with ratio of Pao2 to Fio2 less than 150 experienced a greater relative improvement in oxygenation with prone positioning than patients with ratio of Pao2 to Fio2 greater than or equal to 150 (median percent change in ratio of Pao2 to Fio2 62 [29-107] vs 30 [10-70], p = 0.002). Among 12 patients, inhaled nitric oxide prior to prone positioning was associated with a significant increase in the ratio of Pao2 to Fio2 (from median 136 [77-168] to 170 [138-213], p = 0.003) and decrease in dead-space-to-tidal-volume ratio (0.54 [0.49-0.58] to 0.46 [0.44-0.53], p = 0.001). Subsequent prone positioning in this subgroup further improved the ratio of Pao2 to Fio2 (from 145 [122-183] to 205 [150-232], p = 0.017) but did not change dead-space-to-tidal-volume ratio.Conclusions and relevanceProne positioning improves oxygenation across the acute respiratory distress syndrome severity spectrum, irrespective of supine respiratory system compliance, positive end-expiratory pressure, or body mass index. There was a greater relative benefit among patients with more severe disease. Prone positioning confers an additive benefit in oxygenation among patients treated with inhaled nitric oxide.
Project description:BackgroundInhaled nitric oxide (iNO) has been widely used in patients with COVID-19-related acute respiratory distress syndrome (C-ARDS), though its physiological effects and outcome are debated in this setting. The objective of this cohort study was to describe the modalities of iNO use, clinical response, and outcomes in a large cohort of C-ARDS patients.MethodsMulticentre, retrospective cohort study conducted in France.ResultsFrom end February to December 2020, 300 patients (22.3% female) were included, 84.5% were overweight and 69.0% had at least one comorbidity. At ICU admission, their median (IQR) age, SAPS II, and SOFA score were 66 (57-72) years, 37 (29-48), and 5 (3-8), respectively. Patients were all ventilated according to a protective ventilation strategy, and 68% were prone positioned before iNO initiation. At iNO initiation, 2%, 37%, and 61% of patients had mild, moderate, and severe ARDS, respectively. The median duration of iNO treatment was 2.8 (1.1-5.5) days with a median dosage of 10 (7-13) ppm at initiation. Responders (PaO2/FiO2 ratio improving by 20% or more) represented 45.7% of patients at 6 h from iNO initiation. The severity of ARDS was the only predictive factor associated with iNO response. Among all evaluable patients, the crude mortality was not significantly different between responders at 6 h and their counterparts. Of the 62 patients with refractory ARDS (who fulfilled extracorporeal membrane oxygenation criteria before iNO initiation), 32 (51.6%) no longer fulfilled these criteria after 6 h of iNO. The latter showed significantly lower mortality than the other half (who remained ECMO eligible), including after confounder adjustment (adjusted OR: 0.23, 95% CI 0.06, 0.89, p = 0.03).ConclusionsOur study reports the benefits of iNO in improving arterial oxygenation in C-ARDS patients. This improvement seems more relevant in the most severe cases. In patients with ECMO criteria, an iNO-driven improvement in gas exchange was associated with better survival. These results must be confirmed in well-designed prospective studies.
Project description:OBJECTIVES:To investigate the association between inhaled nitric oxide treatment and ICU mortality and 28-day ventilator-free days in pediatric acute respiratory distress syndrome. DESIGN:Retrospective cohort study. A propensity score for inhaled nitric oxide treatment was developed and used in the analysis. SETTING:Two quaternary care PICUs. PATIENTS:Children with pediatric acute respiratory distress syndrome. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:There were 499 children enrolled in this study with 143 (28.7%) receiving inhaled nitric oxide treatment. Children treated with inhaled nitric oxide were more likely to have a primary diagnosis of pneumonia (72% vs 54.8%; p < 0.001), had a higher initial oxygenation index (median 16.9 [interquartile range, 10.1-27.3] vs 8.5 [interquartile range, 5.8-12.2]; p < 0.001), and had a higher 72-hour maximal Vasoactive-Inotrope Score (median 15 [interquartile range, 6-25] vs 8 [interquartile range, 0-17.8]; p < 0.001) than those not receiving inhaled nitric oxide. Mortality was higher in the inhaled nitric oxide treatment group (25.2% vs 16.3%; p = 0.02), and children in this group had fewer 28-day ventilator-free days (10 d [interquartile range, 0-18 d] vs 17 d (interquartile range 5.5-22 d]; p < 0.0001). We matched 176 children based on propensity score for inhaled nitric oxide treatment. In the matched cohort, inhaled nitric oxide treatment was not associated with mortality (odds ratio, 1.3 [95% CI, 0.56-3.0]) or 28-day ventilator-free days (incidence rate ratio, 0.91 [95% CI, 0.80-1.04]). These results remained consistent in the entire study cohort when the propensity score for inhaled nitric oxide treatment was used for either inverse probability weighting or stratification in regression modeling with the exception that subjects treated with inhaled nitric oxide were more likely to have 0 ventilator-free days (p ? 0.02). In secondary analysis stratified by oxygenation response, inhaled nitric oxide treatment was not associated with mortality or 28-day ventilator-free days in children with a positive oxygenation response (all p > 0.2) CONCLUSIONS:: Treatment with inhaled nitric oxide in pediatric acute respiratory distress syndrome is not associated with improvement in either mortality or ventilator-free days and may be associated with harm. Further prospective trials are required to define the role of inhaled nitric oxide treatment in pediatric acute respiratory distress syndrome.
Project description:ObjectivesBoth oxygenation and peak inspiratory pressure are associated with mortality in pediatric acute respiratory distress syndrome. Since oxygenation and respiratory mechanics are linked, it is difficult to identify which variables, pressure or oxygenation, are independently associated with outcome. We aimed to determine whether respiratory mechanics (peak inspiratory pressure, positive end-expiratory pressure, ΔP [PIP minus PEEP], tidal volume, dynamic compliance [Cdyn]) or oxygenation (PaO2/FIO2) was associated with mortality.DesignProspective, observational, cohort study.SettingUniversity affiliated PICU.PatientsMechanically ventilated children with acute respiratory distress syndrome (Berlin).InterventionsNone.Measurements and main resultsPeak inspiratory pressure, positive end-expiratory pressure, ΔP, tidal volume, Cdyn, and PaO2/FIO2 were collected at acute respiratory distress syndrome onset and at 24 hours in 352 children between 2011 and 2016. At acute respiratory distress syndrome onset, neither mechanical variables nor PaO2/FIO2 were associated with mortality. At 24 hours, peak inspiratory pressure, positive end-expiratory pressure, ΔP were higher, and Cdyn and PaO2/FIO2 lower, in nonsurvivors. In multivariable logistic regression, PaO2/FIO2 at 24 hours and ΔPaO2/FIO2 (change in PaO2/FIO2 over the first 24 hr) were associated with mortality, whereas pressure variables were not. Both oxygenation and pressure variables were associated with duration of ventilation in multivariable competing risk regression.ConclusionsImprovements in oxygenation, but not in respiratory mechanics, were associated with lower mortality in pediatric acute respiratory distress syndrome. Future trials of mechanical ventilation in children should focus on oxygenation (higher PaO2/FIO2) rather than lower peak inspiratory pressure or ΔP, as oxygenation was more consistently associated with outcome.
Project description:Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support.
Project description:The aims of the study were to assess the long-term safety and compare neurodevelopmental outcomes in school-age children born prematurely who received inhaled nitric oxide or placebo during the first week of life in a randomized, double-blinded study. Children treated with inhaled nitric oxide had previously been shown to have decreased intraventricular haemorrhage and periventricular leukomalacia as newborns and decreased cognitive impairment at 2 years (L.W. Doyle and P.J. Anderson. (2005) Arch Dis Child Fetal Neonatal Ed, 90, F484-F8).It is follow-up study of medical outcomes, neurodevelopmental assessment and school readiness in 135 of 167 (81%) surviving premature infants seen at 5.7±1.0 years.Compared to placebo-treated children (n=65), iNO-treated children (n=70) demonstrated no difference in growth parameters, school readiness or need for subsequent hospitalization. However, iNO-treated children were less likely to have multiple chronic morbidities or technology dependence (p=0.05). They also had less functional disability (p=0.05).These results demonstrate the long-term safety of iNO in premature infants. Furthermore, iNO treatment may improve health status by decreasing the incidence of severe ongoing morbidities and technology dependence and may also decrease the incidence of educational and community functional disability of premature infants at early school age.
Project description:BackgroundThe inhaled vasodilators nitric oxide and epoprostenol may be initiated to improve oxygenation in mechanically ventilated patients with severe acute respiratory failure (ARF); however, practice patterns and head-to-head comparisons of effectiveness are unclear.Research questionWhat are the practice patterns and comparative effectiveness for inhaled nitric oxide and epoprostenol in severe ARF?Study design and methodsUsing a large US database (Premier Healthcare Database), we identified adult patients with ARF or ARDS who were mechanically ventilated and started on inhaled nitric oxide, epoprostenol, or both. Leveraging large hospital variation in the choice of initial inhaled vasodilator, we compared the effectiveness of inhaled nitric oxide with that of epoprostenol by limiting analysis to patients admitted to hospitals that exclusively used either inhaled nitric oxide or epoprostenol. The primary outcome of successful extubation was modeled using multivariate Fine-Grey competing risk (death or hospice discharge) time-to-event models.ResultsAmong 11,200 patients (303 hospitals), 6,366 patients (56.8%) received inhaled nitric oxide first, 4,720 patients (42.1%) received inhaled epoprostenol first, and 114 patients (1.0%) received both therapies on the same day. One hundred four hospitals (34.3%; 1,666 patients) exclusively used nitric oxide and 118 hospitals (38.9%; 1,812 patients) exclusively used epoprostenol. No differences were found in the likelihood of successful extubation between patients admitted to nitric oxide-only hospitals vs those admitted to epoprostenol-only hospitals (subdistribution hazard ratio, 0.97; 95% CI, 0.80-1.18). Also no differences were found in total hospital costs or death. Results were robust to multiple sensitivity analyses.InterpretationLarge variation exists in the use of initial inhaled vasodilator for respiratory failure across US hospitals. Comparative effectiveness analyses identified no differences in outcomes based on inhaled vasodilator type.