Electrical impedance tomography-guided positive end-expiratory pressure titration in ARDS: a systematic review and meta-analysis

Abstract

Purpose: Assessing efficacy of electrical impedance tomography (EIT) in optimizing positive end-expiratory pressure (PEEP) for acute respiratory distress syndrome (ARDS) patients to enhance respiratory system mechanics and prevent ventilator-induced lung injury (VILI), compared to traditional methods.

Methods: We carried out a systematic review and meta-analysis, spanning literature from January 2012 to May 2023, sourced from Scopus, PubMed, MEDLINE (Ovid), Cochrane, and LILACS, evaluated EIT-guided PEEP strategies in ARDS versus conventional methods. Thirteen studies (3 randomized, 10 non-randomized) involving 623 ARDS patients were analyzed using random-effects models for primary outcomes (respiratory mechanics and mechanical power) and secondary outcomes (PaO₂/FiO₂ ratio, mortality, stays in intensive care unit (ICU), ventilator-free days).

Results: EIT-guided PEEP significantly improved lung compliance (n = 941 cases, mean difference (MD) = 4.33, 95% confidence interval (CI) [2.94, 5.71]), reduced mechanical power (n = 148, MD = - 1.99, 95% CI [- 3.51, - 0.47]), and lowered driving pressure (n = 903, MD = - 1.20, 95% CI [- 2.33, - 0.07]) compared to traditional methods. Sensitivity analysis showed consistent positive effect of EIT-guided PEEP on lung compliance in randomized clinical trials vs. non-randomized studies pooled (MD) = 2.43 (95% CI - 0.39 to 5.26), indicating a trend towards improvement. A reduction in mortality rate (259 patients, relative risk (RR) = 0.64, 95% CI [0.45, 0.91]) was associated with modest improvements in compliance and driving pressure in three studies.

Conclusions: EIT facilitates real-time, individualized PEEP adjustments, improving respiratory system mechanics. Integration of EIT as a guiding tool in mechanical ventilation holds potential benefits in preventing ventilator-induced lung injury. Larger-scale studies are essential to validate and optimize EIT's clinical utility in ARDS management.

Keywords: ARDSNet; Mechanical ventilation; Ventilator-induced lung injury.

Fig. 1

Study selection process diagram: Initially, 421 records were identified, which were then deduplicated to yield 243 unique citations. Subsequently, 218 records were excluded based on eligibility criteria. Following a comprehensive review of 25 full-text articles, an additional 12 studies were excluded based on specific criteria. This resulted in 13 studies that met the inclusion criteria and were included in the analysis

Fig. 2

Comparison of lung compliance between EIT-guided and conventional PEEP titration. CI confidence interval, df degrees of freedom, I² heterogeneity statistic, IV inverse variance method

Fig. 3

Comparison of mechanical power between EIT-guided and conventional PEEP titration. MP mechanical power, CI confidence interval, df degrees of freedom, I² heterogeneity statistic, IV inverse variance method

Fig. 4

Comparison of driving pressure between EIT-guided and conventional PEEP titration. CI confidence interval, df degrees of freedom, I² heterogeneity statistic, IV inverse variance method

Fig. 5

Forest plots of sensitivity analysis for lung compliance: a Excluding studies with high risk of bias, b excluding studies with recruitment maneuver before PEEP, c excluding studies with significant positive treatment effect, d obese and non-obese patients, e ODCL method versus conventional method, f EIT-guided PEEP versus ARDSNet PEEP/FiO2 table, g ODCL method versus ARDSNet PEEP/FiO₂ table. RM recruitment maneuver, BMI body mass index, ODCL intercept point of cumulated collapse and overdistension percentages curves, CI confidence interval, df degrees of freedom, I² heterogeneity statistic, IV inverse variance method

Fig. 5

Forest plots of sensitivity analysis for lung compliance: a Excluding studies with high risk of bias, b excluding studies with recruitment maneuver before PEEP, c excluding studies with significant positive treatment effect, d obese and non-obese patients, e ODCL method versus conventional method, f EIT-guided PEEP versus ARDSNet PEEP/FiO2 table, g ODCL method versus ARDSNet PEEP/FiO₂ table. RM recruitment maneuver, BMI body mass index, ODCL intercept point of cumulated collapse and overdistension percentages curves, CI confidence interval, df degrees of freedom, I² heterogeneity statistic, IV inverse variance method