Synopsis
Use the preparation period to investigate anaemia, restore nutritional reserve and support safer changes in smoking and alcohol use without creating avoidable delay or withdrawal risk.
- Investigate the cause of anaemia early; a low haemoglobin is a finding rather than a complete diagnosis.
- Choose oral or intravenous iron according to confirmed deficiency, tolerance, absorption and time before surgery.
- Assess recent weight loss and intake as well as BMI; obesity does not exclude malnutrition.
Key red flags
A history of withdrawal seizures, delirium tremens, morning drinking or symptoms relieved by alcohol suggests that abrupt cessation may be dangerous. Obtain specialist assessment and an appropriate monitored withdrawal plan. Agitation or tremor before surgery may need urgent treatment rather than an assumption of anxiety.
A person with very limited intake who develops weakness, oedema, arrhythmia or respiratory difficulty after feeding needs urgent assessment for electrolyte and fluid shifts. Identify risk before increasing nutrition and involve the nutrition team; an apparently generous calorie prescription can create harm.
Reasoning priorities
Distinguish iron deficiency from other causes and identify the underlying disease.
Review the full blood count, indices, ferritin and relevant inflammatory markers, with additional tests guided by the pattern and history. Ferritin can rise with inflammation, so a reassuring isolated value may not exclude iron-restricted erythropoiesis. Ongoing blood loss, renal disease and mixed deficiencies may coexist.
Worked reasoning
A 62-year-old is preparing for a major colorectal cancer operation in four weeks. Haemoglobin is 98 g/L, ferritin is low, and weight has fallen from 75 kg to 68 kg over three months. They stopped iron tablets because of nausea and have been eating mainly soup.
- Identify separate but related problems: confirmed iron deficiency, substantial unintentional weight loss and inadequate intake. Calculate the weight change as 7/75, approximately 9.3%, rather than assuming the current BMI captures the decline. Assess symptoms and whether there is ongoing bleeding or another deficiency.
- Discuss the anaemia pathway with the surgical and anaesthetic teams. Oral intolerance and the limited preparation time make intravenous iron a reasonable consideration under NICE guidance, but the specific product and calculated dose require an appropriate prescribing assessment. Do not default to red-cell transfusion simply to normalise a preoperative number.
- Refer for dietetic assessment of energy, protein and micronutrient needs and the cause of restricted eating. Check whether obstruction, pain or intolerance limits what is feasible. Assess refeeding risk before rapidly increasing support; the plan must fit the functioning gastrointestinal tract and the operation’s urgency.
- Agree an active four-week plan with dates for treatment, reassessment and communication. The final decision about timing weighs likely benefit from preparation against cancer-related harm from delay. Name the team responsible for deciding whether new findings change the planned operation.
- At review, verify tolerance, intake, haemoglobin trend and functional progress. If the expected improvement has not occurred, investigate the reason and modify treatment rather than repeating the same instructions. Ensure postoperative nutrition and anaemia follow-up are included in the discharge plan.