Pharmacological management of delirium after cardiac surgery. A survey of UK cardiac centres

Abstract Introduction In cardiac surgery, 25% of patients develop post-operative delirium (POD); significantly more than in general surgery.[1] POD leads to serious consequences, including falls, prolonged hospitalisation and increased healthcare costs.[1] When non-pharmacological management is ineffective, and the patient is at risk of harm, medication is used to treat symptoms.[2] Anecdotally, medication choices vary widely between UK cardiac centres. Comparing local prescribing guidelines and surveying existing practice will inform the direction of future research into effective pharmacological strategies for managing delirium after cardiac surgery. Aim To determine the extent of variation in drug choices for the management of POD at 32 UK cardiac centres. Methods All NHS adult cardiac centres listed on the Society for Cardiothoracic Surgery website were emailed a Freedom of Information (FOI) request. Centres were asked to provide their local POD guidelines and answer ten questions relating to prescribing practice. Questions covered the use of preventative agents, and preferred treatment options for symptomatic delirium. Reminders were emailed to non-respondents after three months. Responses were collated at six months. Descriptive statistics were used to analyse the data. Results The response rate was 91% (29/32). No two centres had the same treatment pathway. Two-thirds used haloperidol first line; the only product licensed for delirium.[2] Overall, responses showed no consensus on the prescribing sequence of drug classes, and variation was seen within each class (Fig. 1). At 12 centres, delirious patients with disrupted sleep were prescribed melatonin. In 17 centres, melatonin was unavailable (12 cited insufficient evidence of efficacy, five had not evaluated its use). Conclusion There is widespread prescribing variation for POD after cardiac surgery. In the absence of licensed medication options, further studies are needed to assess the efficacy and comparative effectiveness of ‘off label’ medicines, enabling the production of clear national guidance to inform practice at a local level. Study design strengths: NHS organisations have a legal obligation to respond to FOI requests which gives high survey response rates. Study design limitations: Relying on the FOI team at each cardiac centre to identify a suitable survey respondent may increase inter-respondent variation.