To determine the predictors of need of mechanical ventilation (MV) and reintubation, after a planned extubation, in patients with acute respiratory failure (ARF) secondary to COPD (COPD-ARF).
Eighty-two patients with COPD-ARF, admitted to ICU, were included. Clinical profile and laboratory abnormalities at the time of admission to ICU including APACHE II score were recorded. Study group was split on the basis of need of MV and parameters were compared between the two groups. In the MV group, number of weaning trials with the mode of weaning was recorded. PaCO2 levels at initiation of weaning, extubation and rise in 12 hrs after extubation were recorded and compared along with the parameters at baseline, in the patients who required reintubation with those who did not.
Independent predictors of need of MV were pH<7.26 (OR,95%CI: 4.9, 1.1–21.3; p=0.03) and serum albumin<3.5 g/dL (OR, 95%CI: 6.3, 1.4–27.7; p=0.01). Weaning trials, given in 45 patients (T-piece:n=31, 68.9%; reducing SIMV breaths:n=14, 17.2%), lead to a planned extubation. Reintubation was required in eight patients (17.8%). PaCO2 rise 12 hours after extubation (OR, 95%CI: 1.25,1.0–1.5; p=0.01) and high APACHE II score (OR, 95%CI: 1.33,1.0–1.7; p=0.03) were independent predictors of need of reintubation. A cut-off level of 7.2 mmHg for CO2 rise had sensitivity and specificity of 100% and 84% respectively whereas cut-off of 11.5 for APACHE II score had sensitivity of 87.5 % and specificity of 62.2%. Reintubation was associated with increased ICU stay (16 days & 9 days, p=0.017) and mortality (75% vs 23%, p=0.002).
Presence of pH<7.26 and serum albumin<3.5 g/dL are independent predictors of need of MVin patients with COPD-ARF. Reintubation rates are significant in these patients. High APACHE II score at baseline and a rising PaCO2 levels after extubation independently predict need of reintubation.
COPD patients with acidemia and hypoalbuminemia are most likely to require MV. A high APACHE II score at admission and a sharply rising PaCO2 after extubation should alert the physician to the need to reintubation.
G.C. Khilnani, None.