Pre-Operative Management

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Last updated: December 31, 2022
Revisions: 27

Last updated: December 31, 2022
Revisions: 27

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The management of pre-operative patients is a core function of junior doctors. Although specific management is provided in this article, each hospital may differ slightly in its protocols, therefore it is advised that you refer to any local guidelines.

A useful tool for structuring your management plan is to utilise the acronym ‘RAPRIOP’ (this can be used for the management of any patient): Reassurance, Advice, Prescription, Referral, Investigations, Observations, Patient understanding and follow-up


It almost goes without saying that most patients are anxious about their upcoming surgery. Recognition of this fact and a kind word will make a big difference to a wary patient.


All pre-operative patients should be given advice regarding fasting. A typical pre-operative regime is no food up to 6 hours before surgery, with clear fluids only up to 2 hours before surgery*.

Fasting ensures that the stomach is empty of contents, in turn reduces the risk of aspiration, which can cause aspiration pneumonitis and / or aspiration pneumonia.

*Some centres are moving towards allowing free access to water and encouraging drinking as it has been shown to be association with no increase in adverse events and a significant reduction in postoperative nausea and vomiting


The management of the pre-operative drug regime falls into three categories; prescriptions to stop, prescriptions to alter, and prescriptions to start. In certain patients, bowel preparation and blood products may also need to be considered.

Drugs To Stop

These commonly stopped medications can be remembered as ‘CHOW’.

  • Clopidogrel – stopped 7 days prior to surgery due to bleeding risk; aspirin and other anti-platelets can often be continued and minimal effect on surgical bleeding
  • Hypoglycaemics – see ‘Diabetes Mellitus’ below
  • Oral contraceptive pill (OCP) or Hormone Replacement Therapy (HRT) – stopped 4 weeks before surgery due to DVT risk. Advise the patient to use alternative means of contraception during this time period.
  • Warfarin* – usually stopped 5 days prior to surgery due to bleeding risk and commenced on therapeutic dose low molecular weight heparin
    • Surgery will often only go ahead if the INR <1.5, so you may have to reverse the warfarinisation with PO Vitamin K if the INR remains high on the evening before

*Direct Oral AntiCoagulants (DOACs), such as Rivaroxaban, Apixaban, or Edoxaban, will also need stopping pre-operatively, however the duration of this depends on the type used

Drugs To Alter

  • Subcutaneous insulin – may be switched to variable rate intravenous insulin infusion (VRIII), as discussed below
  • Long-term steroids – must be continued, due to the risk of Addisonion crisis if stopped
    • If the patient cannot take these orally, switch to intravenous (a simple conversion rate is 5mg PO prednisolone = 20mg IV hydrocortisone)

Pre-Operative Steroid Prescribing

A patient undergoing surgery will elicit a stress response in proportion to the extent of trauma and metabolic insult. A key part of the stress response is activation of the HPA axis, resulting in an increase in the release of endogenous corticosteroids.

Patients on steroid therapy (more than physiological replacement) for over two weeks may experience HPA axis suppression. Patients with confirmed or suspected HPA axis suppression are therefore at risk of acute adrenal insufficiency peri-operatively due to their attenuated ability to mount a sufficient endogenous steroid response.

In such patients, peri-operative stress-dose corticosteroid therapy is warranted. No definitive guidelines exist regarding the exact amounts of steroid that should be given, however the decisions around specific dosing is often dependent on the type of surgery being performed and patient pre-operative steroid prescription.

Drugs To Start      

  • Low Molecular Weight Heparin – the admitting doctor should complete a VTE Risk Assessment and prescribe appropriately, unless any contra-indications present
    • Patients undergoing major surgery for cancer or lower limb joint replacement are often discharged with TEDs and 28 days of prophylactic dose low molecular weight heparin (in the absence of contraindications)
  • Anti-Embolic Stockings – all patients should be prescribed and receive below knee anti-embolic stocking; contraindications for their use includes severe peripheral vascular disease, peripheral neuropathy, any recent skin graft, or severe eczema
    • Additionally, some patients with have intermittent pneumatic compression (flowtrons) during the operation; these may be continued post operatively, if for example the patient is particularly high risk, such as the ventilated patient admitted to ITU
  • Antibiotic prophylaxis – patients having orthopaedic, vascular, or gastrointestinal surgery will often require prophylactic antibiotics, however it depends on the surgery being performed and surgeon preference

Diabetes Mellitus       

The perioperative care of patients with diabetes mellitus (DM) is becoming increasingly common. The exact pre-operative management varies between patients, but general guidelines can be followed; any concerns or queries, ensure to liaise with the local diabetic team for advice.

Patients with DM should be first on the list where possible, to avoid prolonged fasting. Throughout the procedure, their blood glucose (BM) levels should be checked regularly.

Patients on insulin will often need their doses adjusting pre-operatively, and any prolonged or major surgery will likely need the patient placed on a variable rate intravenous insulin infusion (VRIII) (often termed a “Sliding Scale”), that is often continued for a short period post-operatively as well.

For patients with diet-controlled DM, often no action is required peri-operatively. For patients on oral hypoglycaemics, often these can be stopped the day before the surgery, however this will vary depending on the specific oral hypoglycaemic agent.

Bowel Preparation

Patients having colorectal surgery may need bowel preparation (laxatives or enemas) to clear their colon pre-operatively (and there is some evidence to suggest it can improve peri-operative outcomes).

The exact protocol will vary between hospitals but a general guide is:

  • Upper GI, HPB, or small bowel surgery: none required
  • Right hemi-colectomy or extended right hemi-colectomy: none required
  • Left hemi-colectomy, sigmoid colectomy, or abdominal-perineal resection: Phosphate enema on the morning of surgery
  • Anterior resection: 2 sachets of picolax the day before surgery

Blood Products

It is essential to ensure all patients undergoing major GI, HPB, vascular, gynaecological or orthopaedic surgery have a group and save requested. Others will need blood cross-matching in advance. Read more about prescribing blood products here.


Consider where the patient may need a HDU or ITU bed to be booked. Any concern, it is best to discuss this with your senior.


There are a range of pre-operative investigations that can be requested. The nature of the investigations required depends on a number of factors, including co-morbidities, patient age, and the procedure itself. Read more about pre-operative investigations here.

Patient Understanding and Follow Up

Ensure that the patient is fully informed and understands the plan for their care and discharge. Most major surgical patients will require an appointment in the follow-up clinic, so ensure that this done at a time which the operating surgeon wishes.