Driving pressure and acute respiratory distress syndrome in critically ill patients

Personalized ventilation adjustment in ARDS: A systematic review and meta-analysis of image, driving pressure, transpulmonary pressure, and mechanical power

BACKGROUND

Acute Respiratory Distress Syndrome (ARDS) necessitates personalized treatment strategies due to its heterogeneity, aiming to mitigate Ventilator-Induced Lung Injury (VILI). Advanced monitoring techniques, including imaging, driving pressure, transpulmonary pressure, and mechanical power, present potential avenues for tailored interventions.

OBJECTIVE

To review some of the most important techniques for achieving greater personalization of mechanical ventilation in ARDS patients as evaluated in randomized clinical trials, by analyzing their effect on three clinically relevant aspects: mortality, ventilator-free days, and gas exchange.

METHODS

Following PRISMA guidelines, we conducted a systematic review and meta-analysis of Randomized Clinical Trials (RCTs) involving adult ARDS patients undergoing personalized ventilation adjustments. Outcomes were mortality (primary end-point), ventilator-free days, and oxygenation improvement.

RESULTS

Among 493 identified studies, 13 RCTs (n = 1255) met inclusion criteria. No personalized ventilation strategy demonstrated superior outcomes compared to traditional protocols. Meta-analysis revealed no significant reduction in mortality with image-guided (RR 0.88, 95 % CI 0.70-1.11), driving pressure-guided (RR 0.61, 95 % CI 0.29-1.30), or transpulmonary pressure-guided (RR 0.85, 95 % CI 0.58-1.24) strategies. Ventilator-free days and oxygenation outcomes showed no significant differences.

CONCLUSION

Our study does not support the superiority of personalized ventilation techniques over traditional protocols in ARDS patients. Further research is needed to standardize ventilation strategies and determine their impact on mechanical ventilation outcomes.

Driving pressure decoded: Precision strategies in adult respiratory distress syndrome management

Mechanical ventilation (MV) is an important strategy for improving the survival of patients with respiratory failure. However, MV is associated with aggravation of lung injury, with ventilator-induced lung injury (VILI) becoming a major concern. Thus, ventilation protection strategies have been developed to minimize complications from MV, with the goal of relieving excessive breathing workload, improving gas exchange, and minimizing VILI. By opting for lower tidal volumes, clinicians seek to strike a balance between providing adequate ventilation to support gas exchange and preventing overdistension of the alveoli, which can contribute to lung injury. Additionally, other factors play a role in optimizing lung protection during MV, including adequate positive end-expiratory pressure levels, to maintain alveolar recruitment and prevent atelectasis as well as careful consideration of plateau pressures to avoid excessive stress on the lung parenchyma.

Driving pressure in mechanical ventilation: A review

Driving pressure (∆P) is a core therapeutic component of mechanical ventilation (MV). Varying levels of ∆P have been employed during MV depending on the type of underlying pathology and severity of injury. However, ∆P levels have also been shown to closely impact hard endpoints such as mortality. Considering this, conducting an in-depth review of ∆P as a unique, outcome-impacting therapeutic modality is extremely important. There is a need to understand the subtleties involved in making sure ∆P levels are optimized to enhance outcomes and minimize harm. We performed this narrative review to further explore the various uses of ∆P, the different parameters that can affect its use, and how outcomes vary in different patient populations at different pressure levels. To better utilize ∆P in MV-requiring patients, additional large-scale clinical studies are needed.

Outcomes After Respiratory Extracorporeal Life Support in Teens and Young Adults: An Extracorporeal Life Support Organization Registry Analysis

OBJECTIVES

A recent study from Germany found that survival after respiratory extracorporeal life support (ECLS) was lower among patients 10-20 years old than 20-30 years old. The objective of this study was to compare survival between teenage and young adult patients who receive respiratory ECLS.

DESIGN

Retrospective cohort study.

SETTING

Extracorporeal Life Support Organization registry, an international prospective quality improvement database.

PATIENTS

All patients ages 16-30 years cannulated for respiratory indications from 1990 to 2020 were included. Patients were divided into two groups, teens (16-19 yr old) and young adults (20-30 yr old).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was survival to discharge. Variables were considered for the multivariate logistic regression model if there was both a statistically significant difference (p ≤ 0.05) and a clinically meaningful absolute difference between the groups. A total of 5,751 patients were included, of whom 1,653 (29%) were teens and 4,098 (71%) were young adults. Survival to discharge was higher in young adults than teens, 69% versus 63% (p < 0.001). Severity of illness was higher among teens; however, survival within each stratum defined by Pao2/Fio2 ratio was higher in young adults than in teens. Use of venoarterial ECLS was higher in teens than in young adults, 15% versus 7%, respectively. Teens were more likely to receive high-frequency oscillatory ventilation and this therapy was associated with a longer time from admission to ECLS initiation. After adjusting for variables that differ significantly between the groups, the odds ratio for survival in young adults compared with teens was 1.14 (95% CI, 1.004-1.3).

CONCLUSIONS

In this large multicenter retrospective study, mortality was higher in teens than in young adults who received respiratory ECLS. This difference persisted after adjusting for multiple variables and the mechanism underlying these findings remains unclear.

Driving pressure is not predictive of ARDS outcome in chest trauma patients under mechanical ventilation

BACKGROUND

The relationship between the driving pressure of the respiratory system (ΔPrs) under mechanical ventilation and worse outcome has never been studied specifically in chest trauma patients. The objective of the present study was to assess in cases of chest trauma the relationship between ΔPrs and severity of acute respiratory distress syndrome (ARDS) or death and length of stay.

METHODS

A retrospective analysis of severe trauma patients (ISS > 15) with chest injuries admitted to the Trauma Centre from January 2010 to December 2018 was performed. Patients who received mechanical ventilation were included in our analysis. Mechanical ventilation parameters and ΔPrs were recorded during the stay in the intensive care unit. Association of ΔPrs with mortality and outcomes was specifically studied at the onset of ARDS (ΔPrs_-ARDS) by receiver operator characteristic curve analysis, Kaplan-Meier curves, and multivariate analysis.

RESULTS

Among the 266 chest trauma patients studied, 194 (73%) developed ARDS. ΔPrs was significantly higher in the ARDS group versus in the no ARDS group (11.6 ± 2.4 cm H₂O vs. 10.9 ± 1.9 cm H₂O, p = 0.04). Among the patients with ARDS, no difference according to the duration of mechanical ventilation was found between the high ΔPrs group (ΔPrs_-ARDS > 14 cm H₂O) and the low ΔPrs group (ΔPrs_-ARDS ≤ 14 cm H₂O), (p = 0.75). ΔPrs_-ARDS was not independently associated with the duration of mechanical ventilation (hazard ratio [HR], 1.006; 95% CI, 0.95-1.07; p = 0.8) or mortality (HR, 1.07; 95% CI, 0.9-1.28; p = 0.45). High mechanical power (≥ 12 J/min) was associated with a lower time for weaning of mechanical ventilation in Kaplan-Meier curves but not in multivariate analysis (HR, 0.98; 95% CI, 0.94-1.02; p = 0.22).

CONCLUSION

A high ΔPrs_-ARDS was not significantly associated with an increase in mechanical ventilation duration or mortality risk in ARDS patients with chest trauma in contrast with medical patients.

Driving Pressure Is Associated With Outcome in Pediatric Acute Respiratory Failure

OBJECTIVES

Driving pressure (ratio of tidal volume over respiratory system compliance) is associated with mortality in acute respiratory distress syndrome. We sought to evaluate if such association could be identified in critically ill children.

DESIGN

We studied the association between driving pressure on day 1 of mechanical ventilation and ventilator-free days at day 28 through secondary analyses of prospectively collected physiology data.

SETTING

Medical-surgical university hospital PICU.

PATIENTS

Children younger than 18 years (stratified by Pediatric Mechanical Ventilation Consensus Conference clinical phenotype definitions) without evidence of spontaneous respiration.

INTERVENTIONS

Inspiratory hold maneuvers.

MEASUREMENTS AND MAIN RESULTS

Data of 222 patients with median age 11 months (2-51 mo) were analyzed. Sixty-five patients (29.3%) met Pediatric Mechanical Ventilation Consensus Conference criteria for restrictive and 78 patients (35.1%) for mixed lung disease, and 10.4% of all patients had acute respiratory distress syndrome. Driving pressure calculated by the ratio of tidal volume over respiratory system compliance for the whole cohort was 16 cm H2O (12-21 cm H2O) and correlated with the static airway pressure gradient (plateau pressure minus positive end-expiratory pressure) (Spearman correlation coefficient = 0.797; p < 0.001). Bland-Altman analysis showed that the dynamic pressure gradient (peak inspiratory pressure minus positive end-expiratory pressure) overestimated driving pressure (levels of agreement -2.295 to 7.268). Rematching the cohort through a double stratification procedure (obtaining subgroups of patients with matched mean levels for one variable but different mean levels for another ranking variable) showed a reduction in ventilator-free days at day 28 with increasing driving pressure in patients ventilated for a direct pulmonary indication. Competing risk regression analysis showed that increasing driving pressure remained independently associated with increased time to extubation (p < 0.001) after adjusting for Pediatric Risk of Mortality III 24-hour score, presence of direct pulmonary indication jury, and oxygenation index.

CONCLUSIONS

Higher driving pressure was independently associated with increased time to extubation in mechanically ventilated children. Dynamic assessments of driving pressure should be cautiously interpreted.

Maintenance of low driving pressure in patients with early acute respiratory distress syndrome significantly affects outcomes

Background

Driving pressure (∆P) is an important factor that predicts mortality in acute respiratory distress syndrome (ARDS). We test the hypothesis that serial changes in daily ΔP rather than Day 1 ΔP would better predict outcomes of patients with ARDS.

Methods

This retrospective cohort study enrolled patients admitted to five intensive care units (ICUs) at a medical center in Taiwan between March 2009 and January 2018 who met the criteria for ARDS and received the lung-protective ventilation strategy. ∆P was recorded daily for 3 consecutive days after the diagnosis of ARDS, and its correlation with 60-day survival was analyzed.

Results

A total of 224 patients were enrolled in the final analysis. The overall ICU and 60-day survival rates were 52.7% and 47.3%, respectively. ∆P on Days 1, 2, and 3 was significantly lower in the survival group than in the nonsurvival group (13.8 ± 3.4 vs. 14.8 ± 3.7, p = 0.0322, 14 ± 3.2 vs. 15 ± 3.5, p = 0.0194, 13.6 ± 3.2 vs. 15.1 ± 3.4, p = 0.0014, respectively). The patients were divided into four groups according to the daily changes in ∆P, namely, the low ∆P group (Day 1 ∆P < 14 cmH₂O and Day 3 ∆P < 14 cmH₂O), decrement group (Day 1 ∆P ≥ 14 cmH₂O and Day 3 ∆P < 14 cmH₂O), high ∆P group (Day 1 ∆P ≥ 14 cmH₂O and Day 3 ∆P ≥ 14 cmH₂O), and increment group (Day 1 ∆P < 14 cmH₂O and Day 3 ∆P ≥ 14 cmH₂O). The 60-day survival significantly differed among the four groups (log-rank test, p = 0.0271). Compared with the low ΔP group, patients in the decrement group did not have lower 60-day survival (adjusted hazard ratio 0.72; 95% confidence interval [CI] 0.31–1.68; p = 0.4448), while patients in the increment group had significantly lower 60-day survival (adjusted hazard ratio 1.96; 95% CI 1.11–3.44; p = 0.0198).

Conclusions

Daily ∆P remains an important predicting factor for survival in patients with ARDS. Serial changes in daily ΔP might be more informative than a single Day 1 ΔP value in predicting survival of patients with ARDS.

Driving pressure monitoring during acute respiratory failure in 2020

PURPOSE OF REVIEW

Assess the most recent studies using driving pressure (DP) as a monitoring technique under mechanical ventilation and describe the technical challenges associated with its measurement.

RECENT FINDINGS

DP is consistently associated with survival in acute respiratory failure and acute respiratory distress syndrome (ARDS) and can detect patients at higher risk of ventilator-induced lung injury. Its measurement can be challenged by leaks and ventilator dyssynchrony, but is also feasible under pressure support ventilation. Interestingly, an aggregated summary of published results suggests that its level is on average slightly lower in patients with coronavirus disease-19 induced ARDS than in classical ARDS.

SUMMARY

The DP is easy to obtain and should be incorporated as a minimal monitoring technique under mechanical ventilation.

Advantages and disadvantages of corticosteroid use for acute exacerbation of interstitial pneumonia after pulmonary resection

OBJECTIVES

Acute exacerbation of interstitial pneumonia (AE-IP) is the top cause of 30-day mortality in surgery for lung cancer patients. The general treatment for AE-IP is corticosteroid; however, there are some disadvantages of corticosteroid use after surgery. This study was conducted to report the clinical course of AE-IP after surgery and evaluate the effect of corticosteroid use.

METHODS

This retrospective study was performed on 337 patients with interstitial pneumonia who underwent surgical resection for lung cancer at our institute between 2009 and 2018. AE-IP were observed in 14 patients (4.2%) and their management and clinical outcome were investigated.

RESULTS

All patients received methylprednisolone pulse therapy. Six patients (42.9%) became convalescent after pulse therapy and eight (57.1%) died within 90 days after surgery due to lack of therapeutic efficacy. Oxygenation and ground-glass opacities of the survivors improved within 3 days after starting pulse therapy. Patients who responded to the first pulse also responded to the second pulse. Four patients developed complications including two with bronchopulmonary fistulas that may be related to steroid treatment. Even if the corticosteroid was effective, all AE-IP patients died within 1 year after surgery.

CONCLUSIONS

Corticosteroid therapy is effective for AE-IP after surgery; however, it may lead to severe complications after surgery.

Driving Pressure for Ventilation of Patients with Acute Respiratory Distress Syndrome

Measuring driving pressure (defined by plateau pressure minus positive end-expiratory pressure) is a useful addition to existing variables when setting mechanical ventilation, particularly in the acute respiratory distress syndrome.

Invasive mechanical ventilation in the emergency department

Emergency department (ED) lenght of stay of the patients requiring admission to the intensive care units has increased gradually in recent years. Mechanical ventilation is an integral part of critical care and mechanically ventilated patients have to be managed and monitored by emergency physicians for longer than expected in EDs. This early period of care has significant impact on the outcomes of these patients. Therefore, emergency physicians should have comprehensive knowledge of mechanical ventilation. This review will summarize the current literature of the basic concepts, appropriate clinical applications, monitoring parameters, components and mechanisms of mechanical ventilation in the ED.