Diuretic, opiate and nitrate use in severe acidotic acute cardiogenic pulmonary oedema: analysis from the 3CPO trial.
BACKGROUND
Drug treatments for acute cardiogenic pulmonary oedema (ACPO) have not been rigorously evaluated and recent observational data suggests some agents are related to poorer outcome.


AIM
We aimed to examine the effect of treatment with diuretics, nitrates and opiates on 7-day mortality, acidosis and respiratory distress in UK Emergency Department (ED) patients with severe acidotic pulmonary oedema.


DESIGN
Analysis of data from the 3CPO trial; a multicentre randomized controlled trial.


METHODS
Data were analysed from patients recruited with severe acidotic pulmonary oedema to the 3CPO trial in 26 UK EDs between 2003 and 2007. The effects of these treatments on 7-day mortality, improvement in acidosis (pH change between baseline and 1 h) and improvement in respiratory distress (patient measured breathlessness using a Visual Analogue Score between baseline and 1 h) were tested using univariate logistic regression analysis, and a regression model used to adjust for confounding baseline differences.


RESULTS
Nitrates were given to 947/1048 (90.4%) patients, diuretics to 934/1049 (89.0%) patients and opiates to 541/1052 patients (51.4%). Adjusted analysis showed that opiate treatment was associated with less improvement in acidosis [difference in improvement in pH -0.022, 95% confidence interval (CI) -0.014 to -0.030, P < 0.001], but no difference in mortality or improvement in respiratory distress. We found no evidence that nitrate or diuretic use were associated with any difference in mortality, improvement in acidosis or respiratory distress.


CONCLUSION
Opiate use is associated with less improvement in acidosis during initial treatment and may attenuate effective treatment of severe acidotic ACPO.