HYPERGLYCAEMIA: CAN’T EAT/DRINK

• For symptoms and signs, investigations and guideline to use, see Hyperglycaemia: triage guideline

Appropriate patients

• Patients with blood glucose persistently >12 mmol/L with:
• mild/no dehydration
• no metabolic acidosis nor severe dehydration
• nil-by-mouth
• If long starvation period anticipated (e.g. ≥2 missed meals)
• If capillary blood ketones > 3 mmol/L or urinary ketones > 2 mmol/L, follow DKA or HHS guideline
• for advice on which of DKA or HHS guideline to follow, go to Hyperglycaemia: Triage
• Severe illness with need to achieve good glycaemic control e.g. sepsis
• Vomiting (not DKA)

Important points to consider

• Patients with type 1 diabetes require insulin even if not eating

Investigations

• Blood glucose (capillary)
• if persistently high, check venous blood glucose

• Treat cause
• Refer to diabetes team

• Deliver insulin and IV fluid simultaneously
• only via a set incorporating anti-reflux valves through single cannula
• see IV Insulin & Fluid via one cannula guideline
• Do not use ordinary 3-way taps
• Use IVAC pump to control IV fluid infusion rate and to alert when fluid bag needs replacing
• Never give single doses of insulin e.g. Actrapid
• leads to large swings in glucose

• Consider clinical haemodynamic state and U&E before deciding on type and rate at which IV fluids are prescribed

Amount of fluid

• Set fluid replacement rate to deliver patient’s hourly fluid requirement. This can vary between 83–125 mL/hr (Estimate maintenance volume )
• If patient requires additional resuscitation fluid, give via other arm
• see Fluid resuscitation guideline

Choice of Fluid

• NEVER add potassium chloride to infusion bags
• Ideal fluid of choice to be co-administered with VRII is pre-mixed bag (500 mL) of sodium chloride 0.45% with glucose 5% and potassium chloride :
• If above fluid is not available, use the following:
• if blood glucose ≥14.0 mmol/L, use pre-mixed bag (500 mL) of sodium chloride 0.9% with potassium chloride
• if blood glucose <14.0 mmol/L, use pre-mixed bag (500 mL) of glucose 5% with potassium chloride

Potassium: amount in premixed bag

Previous Insulin regimen

• If patient taking long-acting insulin e.g. glargine (Lantus), detemir (Levemir) or deguldec (Tresiba), continue this
• advise nurse to administer alongside IV insulin
• If patient on insulin pump subcutaneous (CSII), discontinue pump
• contact diabetes team or consultant in charge of patient

IV insulin delivery and infusion

• Use BD micro-fine insulin hypodermic syringes to accurately dose and draw insulin
• do not use ordinary syringe
• 50 units soluble insulin (Actrapid or Humulin S) diluted to 50 mL with sodium chloride 0.9% in 50 mL syringe
• Luer-lok through a spiral or long line delivered by syringe driver pump (so each mL equates to 1 unit of insulin)

Variable rate insulin infusion (VRII)

• Infuse insulin at a variable rate to maintain blood glucose 6–10 mmol/L (acceptable range 4–12 mmol/L)
• Measure capillary blood glucose initially and every hour
• adjust insulin infusion rate accordingly
• Use initial capillary blood glucose to choose insulin infusion rate

• Measure capillary blood glucose initially and every hour
• adjust insulin infusion rate accordingly
• To choose insulin infusion rate, use rate adjuster

Glucose not falling

• If blood glucose remains >12 mmol/L for 3 consecutive readings and is not dropping by ≥3 mmol/L/hr, increase rate of insulin infusion by 1 unit/hr until target achieved.
• When blood glucose falls below 12 mmol/L, use rate adjuster

Potassium Monitoring

• Check serum K⁺ after first bag of fluid has run through
• then check serum K⁺ 4–6 hr after start of infusion depending on rate
• If serum K⁺ remains 3.6–5.5 mmol/L, check U&E daily
• If serum K⁺ is <3.5 mmol/L or >5.5 mmol/L, adjust fluid. See Choice of fluid
• check and adjust K⁺ after each bag until serum K⁺ is 3.6­–5.5 mmol/L
• then check U&E daily

• Once patient biochemically stabilised (pH >7.3, capillary ketones <6 mmol/L) and able to eat and drink, convert to SC insulin regimen
• decide oral hypoglycaemic agents or SC insulin
• if in doubt, ask diabetes team advice

Oral hypoglycaemic agents

• Once patient ready to eat and drink, recommence oral hypoglycaemic agents
• If food intake likely to be reduced, be prepared to withhold or reduce sulphonylureas
• Recommence metformin only if eGFR is >30 mL/min/1.73 m²

SC insulin

• Transition from IV to SC insulin should take place when the next meal-related SC insulin dose is due e.g. with breakfast or lunch
• If already on insulin, continue fixed-rate infusion for 30–60 min after SC insulin administration in conjunction with a meal
• If delay in obtaining diabetes team support, the following is guidance for insulin therapy

Previously using SC insulin dose

• Restart usual insulin
• increasing previous dose by 10–20% for first 2–3 days

insulin naïve patients

• In patient new to insulin, insulin requirements will fall initially as resistance falls
• ensure close supervision during this period
• Caution in patients with low or high BMI as dosing requirement and insulin sensitivity may vary
• Daily insulin requirement is 0.3–0.5 units/kg
• in elderly, renal failure (CKD stage 4 and 5), severe hepatic failure or newly diagnosed type-1 diabetes, use 0.3 units/kg
• all other adult patients, use 0.5 units/kg
• in a 60 kg patient, total starting dose of insulin is either 18 units or 30 units over 24 hr
• Give 50% of the total dose as long-acting analogue (glargine, detemir or degludec) SC before evening meal or before bedtime

Either

• Divide the remaining 50% into 3 equal doses of quick-acting insulin (Novorapid, Humalog or Apidra) SC
• to be given before breakfast, lunch and evening meal

Or

• If twice daily pre-mixed insulin regime to be used – ²/₃ of total dose can be given before breakfast and ¹/₃ before evening meal

Adjusting SC insulin regimen

• Once patient using SC insulin regimen, adjust doses to achieve target range of 6–11 mmol/L
• if using soluble insulin before breakfast, lunch and dinner, plus isophane at 2200 hr, use Table as guide to insulin adjustment, raising or lowering appropriate insulin by 2–4 units

• if patient usually using insulin analogue (e.g. lispro/aspart +/- glargine/detemir), additional isophane may be needed – discuss with diabetes team

• Encourage early mobilisation
• Continue prophylactic LMWH until day of discharge (unless contraindicated)
• Check diabetes team have made appropriate follow-up arrangements or refer to diabetes team for out-patient review
• If patient new to insulin, prescribe needles for insulin pens, lancets and sharps guard