Author(s): Vimal Venugopal , Vito Carone , Manohara Kenchaiah
Urine should be tested for glucose in all hospital patients. Blood glucose must be tested in any patient with glycosuria, any ill patient with diabetes and any patient with a clinical state in which derangements of blood glucose are common or must be excluded (Table 82.1). Hyperglycaemia is defined as plasma glucose concentration >11 mmol/L.
Plasma Blood Glucose >11 mmol/L
- Assess the conscious level and state of hydration, and establish if the patient is taking treatment for diabetes.
- Check urine or plasma for ketones. If there is ketonuria 2+ or greater, or ketonaemia, and the patient is unwell, check venous plasma bicarbonate concentration.
- The patient can now be placed in one of three groups (Table 82.2):
Further management of newly-diagnosed or poorly-controlled diabetes
- If the patient is already on treatment for diabetes, consider increasing the doses of current medication: seek specialist advice.
- If blood glucose is persistently >20 mmol/L, give 4–6 units of rapid-acting insulin SC, repeated every 6 hours, until blood glucose is <11 mmol/L. Check blood glucose 1–2 hourly.
- Use a variable-rate insulin infusion (VRII; ‘sliding scale’) (Table 82.3) if the patient:
- Is critically unwell
- Is vomiting
- Is unable to eat and drink (e.g. in perioperative period)
- Has acute coronary syndrome (DIGAMI regimen; Table 82.4)
- Has a complication of pregnancy
- If the patient is normally on long-acting insulin, this should be continued while the VRII is being administered. The VRII should be continued no longer than 24h, (exceptionally 48h).
Switching from variable-rate insulin infusion to a subcutaneous insulin regimen
- Estimate the daily insulin requirement from the total dose given by infusion over the previous 24h. Give one-third as long-acting background insulin subcutaneously (SC) at 2200h. Divide the remaining two-thirds into three and give as short-acting insulin SC before meals.
- Monitor plasma glucose pre-prandially and at 2200h, and adjust doses of insulin as needed.
- Ask advice from a diabetologist on long-term management. In general:
- Insulin treated DM, with good control (HbA1c <7.5%): return to usual regime.
- Insulin treated DM, with poor control (HbA1c >7.5%): review regimen.
- Oral therapy with good control (HbA1c <7.5%): return to usual therapy.
- Oral therapy with poor control (HbA1c >7.5%): transfer to insulin.
- Newly-diagnosed DM: individualized treatment.
American Diabetes Association (2016) Classification and diagnosis of diabetes. Diabetes Care 39 (Suppl. 1), S13–S22. DOI: 10.2337/dc16-S005.
Palmer BF, Clegg DJ, (2015) Electrolyte and acid-base disturbances in patients with diabetes mellitus. N Engl J Med 373, 548–559.