In general, the mortality of COPD patients requiring hospital admission and MV is high. Many physicians rely on a patient’s spirometry results in guiding advance directive discussions and determining prognosis. There is unclear data to support that pre-morbid spirometry helps predict outcomes in mechanically ventilated COPD patients.
We conducted a retrospective chart review of 33 admissions of 29 patients with COPD requiring MV for acute respiratory failure (ARF) for whom preadmission spirometry data was available. Additional data obtained included age, sex, comorbidities, outpatient therapies, and reason for MV. The primary outcome was in-hospital mortality.
Nineteen (58%) of the patients were male. The mean age was 69.2 years (range 56-85). There were 16 (49%) current smokers and 18 (55%) patients on home oxygen. The mean percent predicted forced expiratory volume in one second (FEV1) was 44.1% and percent predicted forced vital capacity (FVC) was 53.6%. A COPD exacerbation necessitated MV in 51.5% of the admissions, pneumonia in 21.2%, cardiac reasons in 12.1%, and other etiologies in 15.2%. Overall in-hospital mortality was 21.2% (7 of 33). Survivors and non-survivors had no statistically significant difference in preadmission FEV1, FVC, or FEV1/FVC ratio values (Table 1). Multivariate analysis demonstrated significantly lower in-hospital mortality for patients intubated due to COPD exacerbations as compared to other etiologies of ARF (Figure 1).
We conclude that pre-morbid spirometry data does not correlate to in-hospital mortality in COPD patients requiring MV for ARF. It appears that patients with COPD requiring mechanical ventilation for reasons other than a COPD exacerbation have a significantly increased risk of death.
Pre-morbid spirometry data does not appear to aide in discussions of advance directives or prognosis regarding the use of MV in patients with COPD.
Thomas Zanders, None.