Paramedics should delay giving aspirin to patients with stroke

Editor—The Royal College of Physicians has produced clinical guidelines for stroke.¹ These include recommendations for the treatment of acute stroke. The first recommendation is that 300 mg aspirin should be given as soon as possible after the onset of stroke symptoms (if a diagnosis of haemorrhage is considered unlikely). This recommendation is graded A, indicating that the evidence is strong. Because of this the Oxfordshire ambulance service considered having paramedics treat patients with aspirin but consulted widely with clinicians to gain their support.

We found that the recommendation in the guidelines might not be applicable before patients reach hospital. Aspirin has been shown to reduce the risk of early recurrent ischaemic stroke when given within 48 hours of acute stroke.²,³ However, any benefit in reducing the severity of the acute stroke seems to be small, and there is no evidence that overall benefit would be reduced by delaying the administration of aspirin by an hour or so.²,³ Paramedics have been trained to administer aspirin safely in acute myocardial infarction,⁴ but in cases of acute stroke there are potential dangers in using aspirin before the patient reaches hospital.

Firstly, the number of cases was small and the confidence intervals were wide in two studies that found that there was no evidence of harm in patients with acute stroke who had been randomly allocated to receive aspirin before having computed tomography of the brain and who were subsequently found to have had an intracerebral haemorrhage.²,³ Thus, since it is difficult to exclude intracerebral haemorrhage on clinical grounds there remains a potential risk of harm occurring with the inadvertent administration of aspirin to patients with intracerebral haemorrhage.

Secondly, the ability to swallow safely is commonly impaired in the acute phase of stroke. Given the potential difficulties of training paramedics to assess swallowing, aspirin would have to be administered rectally in order to avoid the risk of aspiration.

We therefore decided that if there is no evidence that a short delay in administering aspirin reduces its efficacy in acute stroke and since there is some potential for harm, the indignity of rectal administration by paramedics could not be justified. We wonder what other ambulance services are doing and whether future recommendations should take into account the prehospital phase of treatment.