You are asked to review a 27 year old girl, a known diabetic, admitted following a 48- hour illness characterised by nausea, vomiting and shortness of breath. She has been unable to eat or drink and has not taken her regular insulin. On examination she has a heart rate 137 /min, respiratory rate 36 breaths /min, O2 saturation is 99% on room air, blood pressure 92/34 mm Hg. She weighs 80kg and her blood sugar level is 32 mmol/l. Outline your plan of management for the first 24 hours.

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College Answer

This young lady most probably has diabetic ketoacidosis and is critically unwell. She requires:-

1. Resuscitation:
May need supplemental oxygen
Peripheral iv access
Commence iv fluids (hartmanns, plasmalyte, n/saline or colloid)

500ml to 1 litre stat then reassess BP/HR/RR/
blood test and ABG should be available to adjust fluid therapy
 Maintenance IV fluids with N.Saline, 0.45% saline
 Start 5% dextrose when BSL <15mmol/L

Monitoring:

ECG, pulse oximetry, NIBP
Early Art line and CVC
Bloods for    EUC (Na+, Creat, Urea),Mg++, Phos-, Ca++, FBC, LFTs, BSL 
Urine dipstick
IDC
 
Confirmation of diagnosis: Blood gases, a raised AG metabolic acidosis, ketones in urine/blood

2. Insulin therapy:

Insulin infusion - short acting insulin (actrapid)
Infusion Dose (candidate should provide a dosing regimen and rationale)
- 0.01 to 0.1units/kg/hr (max)
- Daily dose /24 as units per hour

Titrate to decrease in BSL 1-2 mmol/L/hr
Continue until metabolic disturbance is corrected (acidaemia and ketosis) rather than correction of BSL. May need dextrose infusion if BSL drops below normal range

3. Electrolyte replacement:

Potassium:- Start replacement when plasma K+ <5mmol/L as insulin therapy and correction of acidaemia may lead to precipitous fall and arrhythmias
Sodium:- May need to correct Na+ for BSL. Need to take care to avoid large shifts in Na as it may predispose to cerebral oedema
Bicarbonate:- almost no indication for bicarbonate therapy. Phosphate and Mg++ likely to need replacement
**Need very regular (Q2-4h) ABG and EUC for 1st 24 hours to avoid large electrolyte and BSL changes. Need regular urine dipstick q4-6h for ketones.

4. Identify and treat precipitant:

Common precipitants to consider include;
Non compliance and psycho-social issues
Infection:- gastroenteritis, UTI, respiratory tract, cholecystitis, meningitis, cellulitis

Ischaemia:- AMI, stroke, peripheral vascular disease, mesenteric `  ischaemia

Pregnancy

5. Prevention of expected complications:

Hypoglycaemia (q1h BSL, decrease insulin infusion, dextrose infusion) Hyponatraemia (regular electrolyte monitoring)
Hypokalaemia (regular electrolyte monitoring)
Hypomagnasaemia and hypophosphataemia (regular electrolyte monitoring) Venous thromboembolism (sci heparin/LMWH)
Hyperchloraemic acidosis (avoid N/saline when able)

Complications of critical illness (upper GIT bleeding, ARDS..)

Discussion

Like all the management questions, this one can be dissected into manageable pieces:

  • Attention to the ABCS, with management of life-threatening problems simultanous with a rapid focused examination and a brief history.
  • Airway
    • Assess the need for intubation - will rarely be required, unless cardiorespiratory arrest occurs
  • Breathing/ventilation
    • Assess the need for supplemental oxygen- this will rarely be required, as oxygenation is rarely an issue
    • If intubated, maintain a high MV to prevent an exacerbation of acidosis
  • Circulatory support
    • IV fluids and vasopressors may be required if the initial presentation is in a shocked state
  • Supportive management
    • Ensure adequate thiamine supplementation
    • Protect gut mucosa with PPIs
    • DVT prophylaxis (s/c heparin)
  • Monitoring
    • Frequent (hourly) ABGs
    • Frequent (4-6hourly) electrolyte levels
      • watch for hypokalemia and hypophosphataemia
  • Specific management
    • Initial resuscitation with choride-poor fluids (eg. Plasmalyte)
    • Insulin infusion - 0.01 to 0.1units/kg/hr (to reduce the rate of ketogenesis)
    • Add 5% glucose when BSL is under 15mmol/L
    • Correct electrolytes aggressively
    • Search for and address the precipitating cause.

Out there, every man and his dog has a protocol for the management of diabetic ketoacidosis. One Google Scholar search for "management of diabetic ketoacidosis" has yielded several pages of articles, monotonously titled "Management of diabetic ketoacidosis".

As my primary reference, I have chosen a representative statement - the "Joint British Diabetes Societies guideline. Among the various issues raised by the guideline, a few stand out as mildly interesting:

  • You may safely use VBGs instead of ABGs
  • You should use crystalloid IVF (though there was never any controversy)
  • You should use your judgement and give fluids at a careful rate, because there is no evidence regarding any befit from rapid fluid resuscitation
  • The Brits recommend you use saline as your crystalloid of choice, which is heretical. The reasons given were "unfamiliar and not routinely kept on medical wards". My response would be "train your staff and stock better fluids".

References

References

Savage, M. W., et al. "Joint British Diabetes Societies guideline for the management of diabetic ketoacidosis." Diabetic Medicine 28.5 (2011): 508-515.