Every day, doctors and nurses make hundreds of decisions about treatments - like when to start or stop them, or how frequently to give them. Ideally, decisions are based on gold standard evidence from Randomised Controlled Trials (RCTs). Unfortunately, for many treatments little or no evidence exists and clinicians must use knowledge and experience to decide what is best.

As clinicians are all different, this leads to random variation in how treatments are given to patients. For example, magnesium is routinely given in intensive care to prevent abnormal heart rhythms. There is little evidence supporting this, and clinicians vary in how they administer magnesium. Traditional RCTs might be used to examine whether more magnesium is better than less magnesium, but this method is inefficient and expensive for investigating multiple comparative treatment questions.

Clinical trials are becoming more efficient by using existing hospital computer systems to run them. However, research teams continue to perform tasks like randomisation manually. For questions like magnesium supplementation, which occur daily, this is labour intensive and infeasible.

Hospital computer systems also possess mechanisms for prompting and alerting clinicians for particular decisions, reminding them of best practices, warning them of potential problems. These systems may be modified to allow clinicians to randomise patients, under specific conditions.

The investigators propose to assess whether modified computer prompts can be used to highlight the magnesium supplementation decision to clinicians. These would prompt the clinician to evaluate the uncertainty around giving or withholding magnesium in that instance. If in agreement that the optimal decision is unclear, clinicians can choose to randomise the patient within a predetermined trial structure. If the clinician knows better, they may override the prompt and continue with their preference. In both cases, the system learns from the decision and the patient receives optimal care determined by their clinician.

Trial Design:

A single-centre, mixed methods, feasibility study, embedded within the Electronic Health Record System (EHRS). The study will be conducted on critical care units within University College London Hospitals NHS Trust and will involve patients undergoing elective major surgery which necessitates postoperative admission to critical care. The study will be pragmatic in nature, with minimal disruption to usual care pathways.

The study will consist of three phases:

1. Feasibility Phase - Simulation guided semi-structured interviews with clinicians.
2. Intervention Phase - Deployment of electronic prompts to evaluate candidate clinical question.
3. Follow Up Phase - Patient and clinician semi-structured interviews.

Research Hypothesis:

Electronically delivered prompts provide a feasible method of delivering point-of-care randomisation for the evaluation of routine treatments not amenable to investigation using standard clinical trial designs.

Clinical Example Hypothesis:

Liberal magnesium supplementation (serum concentration < 1.0 mmol/L) is superior to a restrictive supplementation strategy (serum concentration < 0.75 mmol/L) for the prevention of Atrial Fibrillation in a general critical care population.

Summary of Interventions:

This study will compare Nudge and Preference electronic Point-Of-Care Randomisation (ePOCR) prompts against their ability to generate compliance with randomised allocations to liberal or restrictive magnesium supplementation strategy.

Following postoperative admission to the critical care unit, participants will undergo randomisation between Nudge or Preference prompts and Liberal or Restrictive magnesium supplementation strategies. After the two randomisations steps are complete, both ePOCR designs follow the same pathway for activation and deployment to the bedside nurse.

Once the EHRS detects a new serum magnesium result has been received, the system will screen the participant against exclusion criteria 1-5. Each new result triggers the same screening process. If the participant is eligible to proceed, the prompt will activate and display to the bedside nurse under two conditions:

1. Accessing of the blood test results in the EHRS.
2. Accessing the supplemental magnesium prescription within the EHRS. Once the prompt has displayed and been acknowledged by the bedside nurse, further activation will be suppressed until a new serum magnesium result becomes available. This process will be tested in silico prior to deployment to the live EHRS and the results of testing made available as part of the study materials.

Where additional supplementation is indicated by the prompt, the nurse retains control over the dose and frequency of administration, as directed by the standardised prescription. All other aspects of postoperative care remain as standard and directed by the clinical team.

Inclusion Criteria:

Patients:

1. Age 18 years or over.
2. Undergoing elective surgery of complexity sufficient to warrant postoperative critical care admission (major/complex major surgery)
3. Must be able to give written informed consent to participate

Clinicians:

1. Must be regularly involved in the care of postoperative patients in critical care.

Exclusion Criteria:

1. Active treatment for bronchospasm preceding deployment of the electronic prompt, defined as patient receiving bronchodilator therapy or Magnesium infusion.
2. Any documented allergy or intolerance to any preparation of supplemental Magnesium.
3. Serum Magnesium result > 1.5 or < 0.5 mmol/L on blood tests obtained during critical care admission .
4. Pregnancy
5. Atrial Fibrillation on initial arrival to critical care.