Diagnostic criteria for DKA
a. Plasma glucose (mg/dl): >250
b. Arterial pH:
- 7.25 to 7.3: mild DKA
- 7 to 7.24: moderate DKA
- <7: severe DKA
c. Serum bicarbonate (mEq/L):
- 15 to 18: mild DKA
- 10 to 15: moderate DKA
- <10: severe DKA
d. Urine and serum ketones (nitroprusside reaction): Positive
e. Effective serum osmolality (mOsm/kg): Variable
- Calculated osmolality = 2 X [Na+] + [Glucose]/18 + [BUN]/2.8
- Effective osmolality = 2 X [Na+] + [Glucose]/18
Sodium concentration is multiplied by a factor of 2 to include the chloride and bicarbonate that are present to maintain electroneutrality. Concentrations of urea and glucose are measured in mg/dl and must be converted to millimoles per liter by the conversion factor of 2.8 for BUN and 18 for glucose.
f. Anion gap (mEq/L): [Na+] – [Cl-] – [HCO3-]
- >10: mild DKA
- >12: moderate and severe DKA
g. Mental status:
- Alert: mild DKA
- Alert/drowsy: moderate DKA
- Stupor/coma: severe DKA
The most widely used diagnostic criteria for DKA are plasma glucose >250 mg/dL, arterial pH <7.3, and presence of ketonemia and/or ketonuria.
Average Fluid and Electrolyte Deficit in DKA
- Free water: 100 ml/kg
- Sodium: 7-10 mEq/kg
- Potassium: 3-5 mEq/kg
- Chloride: 3-5 mmol/kg
- Phosphorous: 1 mmol/kg
Precipitating factors in DKA
Mnemonic: 5 I
- Infections (30-50%): Pneumonia, UTI, Sepsis, Gastroenteritis
- Inadequate insulin (20-40%): Non-compliance, Insulin pump failure
- Ischemia or Infarction:
- Heart: Myocardial (3-6%) – often “silent”
- Brain: Stroke
- Intestine: Mesenteric ischemia
- Lungs: Acute pulmonary embolism
- Intoxication (Alcohol)
- Illness – Acute pancreatitis, Severe burns, Thyrotoxicosis
Important steps to follow in early stage of DKA management
Mnemonic: ACTRAPID (Stepwise)
a. Airway, Breathing and Circulation and Analysis: Stabilize and Send blood for metabolic profile before initiation of fluids)
b. Commence fluid resuscitation:
- Initial fluid therapy: 0.9% NaCl (NS) 1 L/hour (15-20 ml/kg) in 1st hour and until resolution of severe volume depletion (indicated by orthostatic hypotension or supine hypotension with dry mucous membranes and poor skin turgor)
- Calculate corrected sodium: Add 1.6 to 2.4 (average 2) mEq/L sodium for 100 mg/dl plasma glucose above 100 mg/dl
- Hyponatremic patients: NS @ 250-500 ml/hr (4-14 ml/kg) and when plasma glucose reaches 200 mg/dl, change fluid therapy to 5% Dextrose with 1/2 NS @ 150-250 ml/hr
- Eunatremic and hypernatremic patients: 1/2 NS @ 250-500 ml/hr and when plasma glucose reaches 200 mg/dl, change fluid therapy to 5% Dextrose with 1/2 NS @ 150-250 ml/hr
c. Treat potassium:
- Aim: K+ 3.3 to 5.3 mEq/L
- Withold insulin therapy until K+ >3.3 mEq/L or stop insulin whenever K+ <3.3 mEq/L
- Whenever K+ <5.3 mEq/L and adequate urine output of >50 ml/hour, 20 to 30 units (mEq) of K+ should be added to each liter of infusion fluid
- If K+ >5.3 mEq/L, replacement is not needed (but K+ should be checked 2 hourly)
d. Replace Insulin:
- Initiate insulin only after giving 1 L NS over 1 hour and correcting K+ to >3.3 mEq/L
- Bolus then continuous infusion (0.1 U/kg regular insulin followed by continuous infusion of 0.1 U/kg/hr) OR Continuous infusion (0.14 U/kg/hr)
- If blood glucose does not fall by 10% or 50 mg/dl in the first hour of insulin infusion: an additional bolus (0.1 Unit/kg or 0.14 Unit/kg, respectively) may be given and the infusion then continued at the previous rate.
- Once plasma glucose reaches 200 to 250 mg/dL: insulin rate may be decreased by half, or to a rate of 0.02 to 0.05 U/kg/hour. In addition, dextrose should be added to the maintenance IV fluids at this point to prevent potential hypoglycemia.
- The rate of insulin infusion (or the dextrose concentration) should then be adjusted to maintain a plasma glucose level of between 150 and 200 mg/dL.
In patients with mild to moderate DKA that is not complicated by acute MI, congestive heart failure, end-stage renal or hepatic failure, steroid use or pregnancy, alternative subcutaneous regimen can be used. Dosing regimens consist of 0.2 Unit/kg initially, followed by 0.1 Unit/kg every 1 hour or 0.3 Units/kg initially, followed by 0.2 Unit/kg every 2 hours until blood glucose is less than 250 mg/dL. At this point, insulin should be decreased to 0.05 to 0.1 Unit/kg, respectively, every 1 to 2 hours until the DKA is resolved.
In adult patients with pH <6.9, it is recommended that 100 mmol sodium bicarbonate in 400 mL sterile water (an isotonic solution) with 20 mEq KCl be administered at a rate of 200 mL/hour for 2 hours until pH >7.0.
For monitoring of treatment, venous pH is sufficient and should be checked at least each hour in this setting. Treatment should be repeated every 2 hours until pH >7.0.
Complications usually result from the pathological process of DKA or too fast a reversal of the hyperglycaemia/osmolarity. Complications can include dehydration, hypovolaemia, hypotension, electrolyte abnormalities, cardiac arrhythmias, cardiac arrest and cerebral oedema.
Investigate (Monitor) therapy:
Subsequent to initial laboratory evaluation:
- Serum glucose and electrolytes hourly
- Calcium, magnesium and phosphate 2 hourly
- BUN, creatinine and ketones 2-6 hourly
Management and monitoring should continue until DKA resoultion indicated by:
- Plasma glucose <200 mg/dl (At this point, insulin can be decreased by 50%)
- Serum bicarbonate >10 mEq/L
- Venous pH >7.3
- Anion gap <10
The aim is to discharge the patient with sufficient education to prevent re-admission with DKA in the future.