Morphine use questioned in acute cardiac failure
A retrospective observational study has found that the use of iv morphine during emergency admission for acute heart failure appears to be a predictor for mortality.
This study was a retrospective analysis of patients enrolled in the Acute Decompensated Heart Failure National Registry (ADHERE). Patients were divided into 2 groups depending on whether or not they had received iv morphine during their hospital admission.
Statistical analysis was performed to correct for other risk factors that could influence outcomes such as blood urea & creatinine, systolic blood pressure, age, dyspnoea at rest, chronic dialysis, heart rate and abnormal troponin. Further analysis was made according to ejection fraction and the need for mechanical ventilation.
The results showed 147,362 hospitalisations for acute heart failure. Of these 20,782 patients (14.1%) had received morphine and 126,580 (85.9%) had not. The morphine group were more likely to be ventilated (15.4% vs 2.8%, P<0.001) and subsequently had more ICU admissions (38.7% vs 14.4%, P<0.001). More importantly they spent longer in hospital (mean 5.6 vs 4.2 days, P<0.001) and were more likely to die (13.0% vs 2.4%, P<0.001).
Despite adjustment for other risk factors and excluding ventilated patients the use of morphine still remained a strong predictor for mortality (odds ratio 4.84, 95% CI 4.52 - 5.18, P<0.001).
Being called to the treatment room to assess an acutely breathless patient is a stressful experience that many GPs will be familiar with. In situations like this we rely on time-honoured clinical assessment and emergency interventions to reach a provisional diagnosis and stabilise the patient while waiting for the ambulance to arrive. In acute cardiac failure the standard response would be oxygen, an iv loop diuretic and an opiate such as morphine or diamorphine with a suitable antiemetic.
We are used to sifting through the evidence that informs what we do in the consultation particularly in the arena of cardiovascular medicine. However, emergency treatments often go unquestioned.
It must be remembered that this was a retrospective observational hospital- based study and furthermore that the timing of morphine administration was not specified. However, I still think that it provides a good reason to reconsider the role of opiates in the management of acute heart failure.
Peacock WF, Hollander JE, Diercks DB et al. Morphine and outcomes in acute decompensated heart failure: an ADHERE analysis. Emerg Med J 2008; 25:205-209Reviewer
Dr Peter Savill
GPwSI cardiology, Southampton