Severe community acquired pneumonia and ARDS: prognostic factors in infants

Objective

Severe CAP is a common reason for emergency paediatric intensive care (mortality rate: 40–70%). In this population, refractory hypoxemia is frequently associated with poor outcome. Our hypothesis is that the mortality rate in infants with severe CAP and ARDS correlates not only with respiratory impairment, but also with associated organ failure. The purpose of this study is to evaluate organ failures quantified with paediatric modified SOFA (mSOFA) score and to correlate it with mortality.

Design

A retrospective observational study. Period of the study: January 2000–January 2002.

Setting

PICU in a national children's hospital.

Methods

Twenty-two infants with severe CAP meeting ACCP/SCCM criteria for ARDS, age between 6–24 months admitted in the hospital less than 2 days before. Excluded were infants with ARDS from RSV, prematurity and bronchodysplasia, neuromuscular diseases, immunodepression or immunosuppression, congenital cardiopathy. The ventilatory strategy employed was permissive hypercapnia (target pO2 ≥ 60 mmHg, pH > 7.25) with limitation of peak inspiratory pressure (Pplat < 35 cm H₂O) while employng elevated mean airway pressure to ensure maximum lung volume recruitment (PEEP above the lower inflection point on PV curve). Sedation and paralysis were performed according to clinical protocols. At different times, day 1 (D1), day 2 (D2), day 3 (D3), day 7 (D7), day 0 (D0: exitus vs dimission), were collected the mSOFA score, HR, mean arterial pressure, lactate, pH, BE, WBC, PCR, LDH. The end point was mortality in PICU, outcome 2 and 6 months after dimission. The data were analysed with Microsoft Excel 7.0 and Statview McIntosh statistical software: Student's t test (P < 0.05) (*), Mann–Whitney test (P < 0.05) (**), Fisher's exact t test (P < 0.05) (***).

Results

Enrolled patients were divided into two subgroups: deaths (n = 10 [D]) and survivors (n = 12 [S]). Mortality in the PICU was 45%. Eighty per cent of survivors were still alive 6 months later.

The following parameters are statistically different in the studied subgroups: lactate, LDH, mSOFA total, mSOFA coagulation. Lactate (cutoff 3 mmol/l), and mSOFA total (cutoff ≥ 5) were correlated with mortality on admission and in all observations (P < 0.001 Fisher's exact test). There were no other differences between the two subgroups.

Conclusion

The study suggests that the early evaluation of total mSOFA, lactates and LDH can be used to identify infants with severe CAP at elevated risk of death.

Table 1 Population on admission

Table 2 Results