Performance of acute respiratory distress syndrome definitions in a high acuity paediatric intensive care unit

Abstract

Background: For years, paediatric critical care practitioners used the adult American European Consensus Conference (AECC) and revised Berlin Definition (BD) for acute respiratory distress syndrome (ARDS) to study the epidemiology of paediatric ARDS (PARDS). In 2015, the paediatric specific definition, Paediatric Acute Lung Injury Consensus Conference (PALICC) was developed. The use of non-invasive metrics of oxygenation to stratify disease severity were introduced in this definition, although this potentially may lead to a confounding effect of disease severity since it is more common to place indwelling arterial lines in sicker patients. We tested the hypothesis that PALICC outperforms AECC/BD in our high acuity PICU, which employs a liberal use of indwelling arterial lines and high-frequency oscillatory ventilation (HFOV).

Methods: We retrospectively collected data from children < 18 years mechanically ventilated for at least 24 h in our tertiary care, university-affiliated paediatric intensive care unit. The primary endpoint was the difference in the number of PARDS cases between AECC/BD and PALICC. Secondary endpoints included mortality and ventilator free days. Performance was assessed by the area under the receiver operating characteristics curve (AUC-ROC).

Results: Data from 909 out of 2433 patients was eligible for analysis. AECC/BD identified 35 (1.4%) patients (mortality 25.7%), whereas PALICC identified 135 (5.5%) patients (mortality 14.1%). All but two patients meeting AECC/Berlin criteria were also identified by PALICC. Almost half of the cohort (45.2%) had mild, 33.3% moderate and 21.5% severe PALICC PARDS at onset. Highest mortality rates were seen in patients with AECC acute lung injury (ALI)/mild Berlin and severe PALICC PARDS. The AUC-ROC for Berlin was the highest 24 h (0.392 [0.124-0.659]) after onset. PALICC showed the highest AUC-ROC at the same moment however higher than Berlin (0.531 [0.345-0.716]). Mortality rates were significantly increased in patients with bilateral consolidations (9.3% unilateral vs 26.3% bilateral, p = 0.025).

Conclusions: PALICC identified more new cases PARDS than the AECC/Berlin definition. However, both PALICC and Berlin performed poorly in terms of mortality risk stratification. The presence of bilateral consolidations was associated with a higher mortality rate. Our findings may be considered in future modifications of the PALICC criteria.

Keywords: Acute respiratory distress syndrome; American–European consensus conference; Berlin definition; Mechanical ventilation; Mortality; PICU; Paediatric; Paediatric acute lung injury consensus conference; Predictive value.

Fig. 1

Flow diagram of the study population

Fig. 2

Distribution of subjects meeting ARDS criteria stratified by ARDS definition. The blue area represents 102 subjects only meeting PALICC criteria, the dark orange area represents 33 subjects meeting PALICC and Berlin/AECC criteria. The orange area represents the two subjects only meeting Berlin/AECC criteria

Fig. 3

A Differences in severity stratification between PALICC and Berlin definition. Most of the 61 subjects meeting PALICC criteria for mild PARDS did not meet Berlin/AECC criteria, 6 also met criteria of mild ARDS by Berlin and ALI byAECC and 6 met criteria of moderate ARDS by Berlin and ARDS by AECC. Of the 45 subjects meeting PALICC criteria for moderate PARDS by PALICC only 6 subject met criteria for moderate ARDS by Berlin and 4 subjects met criteria for severe ARDS by the Berlin definition. Of the 29 subjects meeting PALICC criteria for severe PARDS 8 also met criteria for severe ARDS by the Berlin definition and 3 met Berlin criteria for moderate ARDS. B Reasons PALICC PARDS subjects are not identified as ARDS by Berlin/AECC. 49 subjects with mild PARDS by PALICC were not identified by Berlin/AECC, mainly due to lack of bilateral consolidations (dark blue). For the 35 subjects that were not identified by Berlin/AECC with moderate PARDS and the 18 subjects with severe PARDS a same pattern was seen

Fig. 4

Distribution of ventilator mode stratified by PARDS severity at three time points (onset of PARDS, and 24 and 48 h after onset). The blue area represents CMV and the orange area HFOV. At onset 135 met PALICC criteria. 98% of the subjects with mild PARDS received CMV, 84.4% of the moderate group received CMV and 65.5% of the subjects meeting PALICC criteria for severe PARDS at onset received CMV. Twenty-four hours after onset still 105 met PALICC criteria (45 mild, 34 moderate, 26 severe). Of the group with mild PARDS 95.5% received CMV, 44.4% of the moderate group received CMV 24 h after onset and only 15.4% of the subjects with severe PARDS 24 h after onset received CMV. Forty-eight hours after onset 90 subject still met PALICC criteria for PARDS (36 mild, 34 moderate, 20 severe). Of the group with mild PARDS after 48 h 86.1% received CMV at that moment, of the moderate group 41.1% received CMV, of the severe group 0% received CMV

Fig. 5

Difference in severity by oxygenation assessment method. Eighteen subjects received HFOV at PARDS onset. When severity was stratified by OI, 1 had mild PARDS, 7 moderate and 10 severe. When the PF is used for the same subjects 3 have mild ARDS, 11 moderate ARDS, 4 severe ARDS. Forty-three subjects received HFOV 24 h after onset, when severity is stratified by the OI 2 meet criteria for mild PARDS, 19 for moderate PARDS, 22 for severe PARDS. When the PF is used 1 doesn’t meet criteria for ARDS anymore, 8 meet criteria for mild ARDS, 27 for moderate and 7 for severe ARDS. Forty-five subjects received HFOV 48 h after onset. Hereof 5 met criteria for mild PARDS, 20 for moderate and 20 for severe PARDS. When these subjects were stratified by PF 3 do not meet ARDS criteria anymore, 11 meet criteria for mild ARDS, 19 for moderate ARDS and 12 meet criteria for severe ARDS

Fig. 6

The effect of ventilation strategy in the first 24 h on the PARDS severity distribution, mortality and VFD. On the left the group of subjects receiving CMV the first 24 h after onset, on the right the group who are switched from CMV to HFOV within the first 24 h after onset. Grey bars represent number of cases with mild, moderate and severe PARDS. Orange dots depict median (with interquartile range) VFD-28 (bottom Y-axis) and blue triangles represent mortality (%) (upper Y-axis)