Synopsis
Select appropriately timed surgical antimicrobial prophylaxis and skin preparation, recognise when infection requires treatment instead, and prevent avoidable harm from allergy, duplication and unsafe application.
- Antibiotic prophylaxis targets contamination at surgery; established infection needs its own treatment and source-control plan.
- NICE recommends prophylaxis for clean implant surgery, clean-contaminated surgery and contaminated surgery.
- Clean uncomplicated surgery without a prosthesis does not routinely require antibiotic prophylaxis.
Key red flags
Pus, perforation with infection or a suspected infected collection changes the task from prevention alone to treatment and source control. Assess physiology and obtain the appropriate surgical and antimicrobial plan. A single prophylactic dose is not a complete response to established intra-abdominal infection.
Visible pooling, wet drapes or incompletely dried preparation creates a hazard when an ignition source is used. Pause and correct the preparation safely according to the product and theatre protocol. Starting diathermy because the surgeon is ready does not make the solvent non-flammable.
Reasoning priorities
Determine whether prevention is needed and which organisms must be covered.
Check the operation, wound class, implant and patient risks against the local formulary. A regimen suitable for skin flora may not cover organisms expected when bowel is opened. The need for anaerobic coverage should be an explicit part of the choice where relevant.
Worked reasoning
A 70-kg adult with normal renal function and no beta-lactam allergy is having a short clean orthopaedic implant procedure without a tourniquet. For this example, the approved local policy specifies cefuroxime 1.5 g IV at induction, with repeat dosing considered for prolonged surgery or major blood loss and no routine postoperative course. The prescription was entered at 07:00; incision is planned at 09:15, but the team initially cannot establish when the dose was given.
- Pause and reconcile the administration record with the giving clinician. They confirm cefuroxime 1.5 g IV was administered from 09:00 to 09:03 at induction; 07:00 was the prescription time, not delivery. Record the verified timing and check allergy and cumulative exposure.
- Calculate that the planned incision is 12 minutes after completion. The operating team expects 45 minutes of surgery, finishing about 10:00, or 60 minutes after the dose began. The selected cefuroxime product describes a roughly 70-minute serum half-life with normal renal function; combine that with the supplied local policy rather than treating prescription age as drug exposure.
- The responsible clinician decides not to give a duplicate dose before incision: a full indicated dose has just been verified. Proceed with the agreed skin-preparation and drying checks. This clean procedure has no expected bowel contamination; do not generalise the selected regimen to bowel surgery needing anaerobic coverage.
- Track actual duration and blood loss. Unexpected prolongation or major loss triggers reassessment and policy-directed repeat dosing; NICE advises giving a repeat dose when an operation lasts longer than the half-life of the antibiotic given. The no-redose decision at 09:15 does not settle every later intraoperative decision.
- At sign-out verify wound classification, any unexpected infection, all actual doses and the agreed stop instruction. If the planned short clean course was unchanged, stop prophylaxis without routine postoperative doses under the supplied policy; a new treatment indication needs its own documented prescription.