Ventilator-Associated Events in Neonates and Children--A New Paradigm

Abstract

Objectives: To identify a pediatric ventilator-associated condition definition for use in neonates and children by exploring whether potential ventilator-associated condition definitions identify patients with worse outcomes.

Design: Retrospective cohort study and a matched cohort analysis.

Setting: Pediatric, cardiac, and neonatal ICUs in five U.S. hospitals.

Patients: Children 18 years old or younger ventilated for at least 1 day.

Interventions: None.

Measurements and main results: We evaluated the evidence of worsening oxygenation via a range of thresholds for increases in daily minimum fraction of inspired oxygen (by 0.20, 0.25, and 0.30) and daily minimum mean airway pressure (by 4, 5, 6, and 7 cm H2O). We required worsening oxygenation be sustained for at least 2 days after at least 2 days of stability. We matched patients with a ventilator-associated condition to those without and used Cox proportional hazard models with frailties to examine associations with hospital mortality, hospital and ICU length of stay, and duration of ventilation. The cohort included 8,862 children with 10,209 hospitalizations and 77,751 ventilator days. For the fraction of inspired oxygen 0.25/mean airway pressure 4 definition (i.e., increase in minimum daily fraction of inspired oxygen by 0.25 or mean airway pressure by 4), rates ranged from 2.9 to 3.2 per 1,000 ventilator days depending on ICU type; the fraction of inspired oxygen 0.30/mean airway pressure 7 definition yielded ventilator-associated condition rates of 1.1-1.3 per 1,000 ventilator days. All definitions were significantly associated with greater risk of hospital death, with hazard ratios ranging from 1.6 (95% CI, 0.7-3.4) to 6.8 (2.9-16.0), depending on thresholds and ICU type. Each definition was associated with prolonged hospitalization, time in ICU, and duration of ventilation, among survivors. The advisory board of the study proposed using the fraction of inspired oxygen 0.25/mean airway pressure 4 thresholds to identify pediatric ventilator-associated conditions in ICUs.

Conclusions: Pediatric patients with ventilator-associated conditions are at substantially higher risk for mortality and morbidity across ICUs, regardless of thresholds used. Next steps include identification of risk factors, etiologies, and preventative measures for pediatric ventilator-associated conditions.

Figure 1.

Rates of pediatric ventilator-associated conditions (VAC) per 1,000 ventilation days for each of the 12 candidate definitions by ICU type (cardiac ICU [CICU], neonatal ICU [NICU], and PICU). The VAC definitions indicate worsening oxygenation via a range of thresholds for increases in daily minimum fraction of inspired oxygen (Fio₂) (by 0.20, 0.25, and 0.30) and daily minimum mean airway pressure (MAP; by 4, 5, 6, and 7 cm H₂O); worsening oxygenation was sustained for ≥ 2 days after ≥ 2 days of stability.

Figure 2.

Adjusted hazard ratios and 95% CIs for hospital death (A), hospital discharge (b), ICU discharge (C), and the end of ventilation episode (D) for patients with a pediatric ventilator-associated condition (VAC) compared with their matches for each candidate VAC definition by ICU type. Analyses B-D are among survivors only. CICU = cardiac ICU, MAP = mean airway pressure, NICU = neonatal ICU.

Figure 2.

Adjusted hazard ratios and 95% CIs for hospital death (A), hospital discharge (b), ICU discharge (C), and the end of ventilation episode (D) for patients with a pediatric ventilator-associated condition (VAC) compared with their matches for each candidate VAC definition by ICU type. Analyses B-D are among survivors only. CICU = cardiac ICU, MAP = mean airway pressure, NICU = neonatal ICU.