Driving Pressure Is a Risk Factor for ARDS in Mechanically Ventilated Subjects Without ARDS

BACKGROUND

Driving pressure (ΔP) has been described as a risk factor for mortality in patients with ARDS. However, the role of ΔP in the outcome of patients without ARDS and on mechanical ventilation has received less attention. Our objective was to evaluate the association between ΔP on the first day of mechanical ventilation with the development of ARDS.

METHODS

This was a post hoc analysis of a multicenter, prospective, observational, international study that included subjects who were on mechanical ventilation for > 12 h. Our objective was to evaluate the association between ΔP on the first day of mechanical ventilation with the development of ARDS. To assess the effect of ΔP, a logistic regression analysis was performed when adjusting for other potential risk factors. Validation of the results obtained was performed by using a bootstrap method and by repeating the same analyses at day 2.

RESULTS

A total of 1,575 subjects were included, of whom 65 (4.1%) developed ARDS. The ΔP was independently associated with ARDS (odds ratio [OR] 1.12, 95% CI 1.07-1.18 for each cm H₂O of ΔP increase, P < .001). The same results were observed at day 2 (OR 1.14, 95% CI 1.07-1.21; P < .001) and after bootstrap validation (OR 1.13, 95% CI 1.04-1.22; P < .001). When taking the prevalence of ARDS in the lowest quartile of ΔP (≤9 cm H₂O) as a reference, the subjects with ΔP > 12-15 cm H₂O and those with ΔP > 15 cm H₂O presented a higher probability of ARDS (OR 3.65, 95% CI 1.32-10.04 [P = .01] and OR 7.31, 95% CI, 2.89-18.50 [P < .001], respectively).

CONCLUSIONS

In the subjects without ARDS, a higher level of ΔP on the first day of mechanical ventilation was associated with later development of ARDS. (ClinicalTrials.gov registration NCT02731898.).

Propensity-Adjusted Comparison of Mortality of Elderly Versus Very Elderly Ventilated Patients

BACKGROUND

The growing proportion of elderly intensive care patients constitutes a public health challenge. The benefit of critical care in these patients remains unclear. We compared outcomes in elderly versus very elderly subjects receiving mechanical ventilation.

METHODS

In total, 5,557 mechanically ventilated subjects were included in our post hoc retrospective analysis, a subgroup of the VENTILA study. We divided the cohort into 2 subgroups on the basis of age: very elderly subjects (age ≥ 80 y; n = 1,430), and elderly subjects (age 65-79 y; n = 4,127). A propensity score on being very elderly was calculated. Evaluation of associations with 28-d mortality was done with logistic regression analysis.

RESULTS

Very elderly subjects were clinically sicker as expressed by higher SAPS II scores (53 ± 18 vs 50 ± 18, P < .001), and their rates of plateau pressure < 30 cm H₂O were higher, whereas other parameters did not differ. The 28-d mortality was higher in very elderly subjects (42% vs 34%, P < .001) and remained unchanged after propensity score adjustment (adjusted odds ratio 1.31 [95% CI 1.16-1.49], P < .001).

CONCLUSIONS

Age was an independent and unchangeable risk factor for death in mechanically ventilated subjects. However, survival rates of very elderly subjects were > 50%. Denial of critical care based solely on age is not justified. (ClinicalTrials.gov registration NCT02731898.).

Inter-country variability over time in the mortality of mechanically ventilated patients

Purpose

Variations in clinical characteristics and management and in the mortality of mechanically ventilated patients have not been sufficiently evaluated. We hypothesized that mortality shows a variability associated with country after adjustment for clinical characteristics and management.

Methods

Analysis of four studies carried out at 6-year intervals over an 18-year period. The studies included 26,024 patients (5183 in 1998, 4968 in 2004, 8108 in 2010, and 7765 in 2016) admitted to 1253 units from 38 countries. The primary outcome was 28-day mortality. We performed analyses using multilevel logistic modeling with mixed-random effects, including country as a random variable. To evaluate the effect of management strategies on mortality, a mediation analysis was performed.

Results

Adjusted 28-day mortality decreased significantly over time (first study as reference): 2004: odds ratio 0.82 (95% confidence interval [CI] 0.72–0.93); 2010: 0.63 (95% CI 0.53–0.75); 2016: 0.49 (95% CI 0.39–0.61). A protective ventilatory strategy and the use of continuous sedation mediated a moderate fraction of the effect of time on mortality in patients with moderate hypoxemia and without hypoxemia, respectively. Logistic multilevel modeling showed a significant effect of country on mortality: median odds ratio (MOR) in 1998: 2.02 (95% CI 1.57–2.48); in 2004: 1.76 (95% CI 1.47–2.06); in 2010: 1.55 (95% CI 1.37–1.74), and in 2016: 1.39 (95% CI 1.25–1.54).

Conclusions

These findings suggest that country could contribute, independently of confounder variables, to outcome. The magnitude of the effect of country decreased over time.

Clinical trials registered with http://www.clinicaltrials.gov (NCT02731898).

Electronic supplementary material

The online version of this article (10.1007/s00134-019-05867-9) contains supplementary material, which is available to authorized users.

Easy prognostic assessment of concomitant organ failure in critically ill patients undergoing mechanical ventilation

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening disease. We evaluated the prognostic utility of Model for End-stage Liver Disease excluding INR (MELD-XI) score for predicting mortality in a cohort of critically ill patients on mechanical ventilation.

METHODS

In total, 11,091 mechanically ventilated patients were included in our post-hoc retrospective analysis, a subgroup of the VENTILA study (NCT02731898). Evaluation of associations with mortality was done by logistic and Cox regression analysis, an optimal cut-off was calculated using the Youden Index. We divided the cohort in two sub-groups based on their MELD-XI score at the optimal cut-off (12 score points).

RESULTS

Peak-, plateau- and positive end-expiratory pressure were higher in patients with MELD-XI>12. Patients with MELD-XI>12 had higher driving pressures (14 ± 6 cmH2O versus 13 ± 6; p < 0.001). MELD-XI was associated with 28-day mortality after correction for relevant cofounders including SAPS II and ventilation pressures (HR 1.04 95%CI 1.03-1.05; p < 0.001. Patients with MELD-XI>12 evidenced both increased hospital (46% versus 27%; p < 0.001) and 28-day mortality (39% versus 22%).

CONCLUSIONS

MELD-XI is independently associated with mortality and constitutes a useful and easily applicable tool for risk stratification in critically ill patients receiving mechanical ventilation.

TRIAL REGISTRATION

NCT02731898, registered 4 April 2016.