Diabetes (Known) Or Blood Glucose > 11 Mmol/L

Diabetic Ketoacidosis

Diagnosis

DKA is defined by:

diabetes (known) or blood glucose > 11 mmol/l

ketonaemia ≥ 3 mmol/l or ketonuria ++

acidosis (pH < 7.3 and/or HCO3 15 mmol/l)

When (not) to admit to hospital

Patients with newly diagnosed Type 1 Diabetes with ‘mild’ ketosis (not vomiting) and hyperglycaemia seldom need hospital admission:

· Refer to Diabetes Team (Diabetes Nurse Specialists ext 4198, bleep 7721 /7881, Mon-Fri 9-5)

· Start sc insulin and push oral fluids.

Admission is essential if the patient is acutely ill (e.g. vomiting, dehydrated), young, or elderly.

Initial assessment and investigations

Airway: naso-gastric tube may be necessary if vomiting / semi-conscious

Breathing: monitor oxygen saturations

Circulation: if SBP < 90mmHg, give 500ml saline iv in 15 mins (can repeat, max 3 times total)

Look for evidence of precipitating cause (infection, silent MI etc)

Baseline tests

· Laboratory blood glucose: must be sent on all patients at outset and when monitoring patients with HI on meter (blood glucose meters record capillary blood glucose to maximum 27.8 mmol/l, higher readings are denoted as ‘HI’ on the meter)

· Urea and electrolytes; CRP and TnT where indicated

· FBC (NB a leucocytosis is common – do not use as marker of infection), clotting

· Venous blood gas (VBG) – avoid arterial gases unless hypoxic (O2 sats <95%)

· Urinalysis: test for ketones, protein, blood, leucocytes and nitrites

· Septic screen: blood cultures, MSU; look for other sites of infection especially feet

· ECG; CXR where clinically indicated

Management

IV line 1 (via pump) IV line 2 (via pump)

Management notes

Patients are ill and require intensive monitoring. Get senior review and consider referral to HDU if:

· Bicarb < 5 mmol/l or pH < 7.1 on presentation

· K+ < 3.5 on admission

· GCS < 12 or abnormal AVPU scale

· O2 saturation < 92% on air if normal baseline respiratory function

· SBP < 90 mmHg; HR > 100 or < 60 bpm

· Anion gap > 16 [AG = Na+ + K+ - (Cl- + HCO3-)]

All patients should have 2 good cannulae inserted; one for fluid replacement, the other for insulin and dextrose. Do not use feet in patients with diabetes.

Monitoring

· Blood glucose (at least) hourly

· Na+, K+ and venous pH + bicarb at 1, 2, 4, 6, 8, 12, 16 hrs

· U+E and Mg2+ at 8 and 24 hrs

Investigations:

· Hyperamylasaemia without pancreatitis is not uncommon

· Magnesium / phosphate usually fall with treatment: replace Mg if < 0.6 mmol/l. Replacing PO4 not generally recommended as doesn’t affect outcome acutely and can cause hypocalcaemia.

Sodium Bicarbonate

Not indicated. Consider only if pH <6.9 and venous bicarbonate <9 and failing to improve despite treatment, but must be discussed with ITU or diabetes consultant first. Give 100 mls of 1.26% sodium bicarbonate; repeat blood gas/bicarbonate 30mins later. Discuss with ITU if no benefit.

Antibiotics

These are not needed as part of routine care. If an infection is the likely precipitant to this episode of DKA, start antibiotics in accordance with the RUH antibiotic policy.

Monitor urine output

Consider inserting a catheter if no urine at 6 hours. Check for ketones

Elderly

If patient has a cardiovascular history and/or is elderly (>65 yrs old), a CVP line, ECG monitoring and urinary catheter are mandatory.

VTE prophylaxis

All patients should have prophylactic enoxaparin (40 / 20 mg sc od) unless contraindicated.

Ongoing care

Refer all patients with DKA to the Diabetes Liaison Nurses; transfer to diabetes ward when clinically stable.

Resolution

· Resume diet as soon as patient is able.

· Once eating, if the pH > 7.3, sc insulin should be resumed if the patient is well. Urinary ketones may take longer to clear.

· If the patient is on a basal bolus regimen and has continued their basal insulin (see above), give usual rapid acting insulin before next meal and stop IV insulin 30 minutes after the meal.

· If patient is on a BD regimen and insulin infusion is to be stopped at lunchtime, give half the normal breakfast dose before lunch and stop IV insulin 30mins after lunch. Recommence usual BD regimen with evening meal. At breakfast or tea, give usual insulin and disconnect pump 30 mins later.

· If patient is newly diagnosed with Type 1 Diabetes and Diabetes Team not available then calculate total daily dose as 0.5 units x body weight in kg (use 0.75 units/kg in teens and obese). Give half as basal (eg Lantus) in the evening and the rest divided equally as bolus (eg NovoRapid) before meals. Alternatively, start patient on Human Mixtard 30 or Novomix 30: 2/3 calculated dose before breakfast and 1/3 with evening meal.

Younger adults

Adequate IV fluid replacement is vital - most patients are fluid depleted by 5 litres or more. However if the patient is 20 yrs and weighs < 60 kg it is particularly important not to replace the fluids too quickly, to avoid cerebral oedema. Therefore all fluids given must be documented.

Assess degree of dehydration:

· 3% dehydration is only just clinically detectable

· mild: 5% - dry mucous membranes, reduced skin turgor

· moderate: 7.5% - above with sunken eyes, poor capillary return

· severe: 10% (+ shock) – very ill, poor perfusion, thready rapid pulse, (hypotension is late sign)

To calculate fluid requirement for first 48 hrs (following treatment for shock):

Requirement = Maintenance + Deficit

Deficit (in litres) = % dehydration x body weight (kg); convert this to ml (don’t use more than 10% dehydration in the calculations).

Maintenance requirements = 60 ml / kg / 48 hrs

Hourly rate = (48 hr maintenance + deficit – resuscitation fluid already given) / 48

Example :

A 50 kg 18 year old girl who is 10% dehydrated, and who has already had 500ml saline, will require

· 10 % x 50 kg = 5000 mls deficit

· plus 60ml x 50kg = 3000 mls maintenance for 48 hours

· hourly rate = 3000 + 5000 - 500 mls resus fluid = 7500 mls over 48 hours = 156 mls/hour

Note

· Use 0.9% saline initially. Monitor Na+ closely: if Na+ stable after 6 – 8 hours consider using dextrose / saline.

· Do not include continuing urinary losses in the calculations

· When good clinical improvement occurs before the 48hr rehydration calculations have been completed, reduce iv input to take account of oral intake

See BSPED DKA Guideline for further information; discuss with paediatric registrar if in doubt.

Diabetes (Known) Or Blood Glucose &gt; 11 Mmol/L