Predictors of mortality in mechanically ventilated COPD patients

ABSTRACT

Patients with chronic obstructive pulmonary disease [COPD] commonly require hospitalization and admission to intensive care unit. It is useful to identify patients at the time of admission who are likely to have poor outcome. This study was carried out to define the predictors of mortality in mechanically ventilated COPD patients and to advice a scoring system using the baseline physiological variables for prognosticating these patients. This study comprised 220 patients with acute respiratory failure [ARF] secondary to COPD, requiring mechanical ventilation [MV] and admitted to the intensive care unit [ICU] of Menoufiya Chest Department over a two-year period. Clinical and demographic data including APACHE III [Acute Physiology and Chronic Health Status Evaluation] score and Charlson co-morbidity score were recorded on MV, at the time of admission to the ICU. In addition, the acid base status, renal and liver functions, serum electrolytes, LDH, CRP and albumin were recorded at the time of presentation. The length of stay in-hospital, in the ICU, and mechanical ventilation were also recorded. The mean serum albumin level was 2.77 +/- 0.39 gm/dL and 2.11 +/- 0.19 for survivors and non-survivors, respectively [p < 0.05]. As regards ABGs; the mean PaCO2 was 54.8 +/- 6.39 mmHg and 76.1 +/- 11.1, PaO2 was 54.8 +/- 7.1 mmHg and 50.2 +/- 4.9, and HCO3 was 34.7 +/- 4.2 mEq/L and 41.6 +/- 4.8 in survivors and non-survivors, respectively [p < 0.05]. Charlson co-morbidity index demonstrated a cut off value of 1.4 +/- 0.3 and 2.6 +/- 0.6 and APACHE III score off value was 45.2 +/- 12.62 and 80.9 +/- 15, for survivors and non-survivors, respectively with statistically significant correlation for both indices [p < 0.05]. The present results indicate that the severity scores, like Charlson co-morbidity and APACHE III scores, are useful and reliable tools for predicting mortality in COPD patients requiring MV. Serum albumin level, renal functions as well as the oxygenation and ventilation parameters can also, predict mortality