2. PREOPERATIVE INVESTIGATIONS

Often it is not necessary to order routine investigations.

The decision will depend on the patient’s age, general health, medications and proposed operation.

Recommendation

Healthy patients less than 40 years of age may require no routine investigations.

Healthy patients between 40 and 60 years of age may require no investigations or may need an electrocardiogram, full blood examination and renal function tests depending on the extent of surgery.

Healthy patients older than 60 years of age are more likely to need an electrocardiogram, full blood examination, renal function tests and, with major surgery a chest X-ray.

For patients who are not healthy, preoperative investigations will depend on the patient’s history and examination.

Recommendation

Full blood examination (haemoglobin or haematocrit, white cell count, platelet count):

anaemia, pallor, jaundice, malignancy, blood loss, infection, cardiac/renal/hepatic
disease and major surgery.

Renal function test (sodium, potassium, urea, creatinine):

cardiac/renal/hepatic disease, diuretics, infection, diabetes, hypertension and dehydration.

Electrocardiogram: 

cardiac/respiratory disease, hypertension, diabetes and atypical abdominal pain.

Blood glucose: 

diabetes, steroid treatment and glycosuria.

Chest X-ray: 

respiratory/cardiac disease, heavy smoking and TB exposure.

Liver function tests (bilirubin, ALT, AST):

cardiac/hepatic disease, jaundice, severe infection, alcohol abuse and biliary surgery.

Thyroid function tests:

check within 1 month of thyroid surgery. Patients with a very low TSH should not have surgery.

APPT: 

heparin, liver disease and major surgery.

INR: 

warfarin, liver disease, jaundice and major surgery.

INR & APPT: 

bleeding tendency, septicaemia and severe pre-eclampsia.

Blood group and cross match: 

major surgery with anticipated blood loss generation
less than 15%.