Hyperglycemia - NYSORA | NYSORA


Learning objectives

  • Recognize signs and symptoms of hyperglycemia
  • Manage and prevent hyperglycemia

Definition and mechanisms

  • An excessive amount of glucose circulates in the plasma, typically above 180-200 mg/dL (or 10-11.1 mmol/L), or fasting blood glucose above 125 mg/dL
  • Symptoms of hyperglycemia develop slowly over several days or weeks
  • However, symptoms may not become noticeable until even higher values (250-300 mg/dL or 13.9-16.7 mmol/L)
  • Due to a low insulin level or if the body can not process insulin properly (insulin resistance)
  • Increased rates of morbidity, mortality, and length of hospital stay

Sign and symptoms

  • High glucose levels in the urine
  • Polyphagia
  • Polydipsia
  • Polyuria
  • Increased thirst
  • Blurred vision
  • Feeling weak or unusually tired
  • Fatigue
  • Restlessness
  • Weight loss or weight gain
  • Dry or itchy skin
  • Seizures
  • Coma

If hyperglycemia is not treated, ketoacidosis occurs:

  • Fruity-smelling breath
  • Dry mouth
  • Abdominal pain
  • Nausea and vomiting
  • Shortness of breath 
  • Kussmaul hyperventilation
  • Confusion
  • Loss of consciousness


  • Type 1 or type 2 diabetes mellitus
  • Infection/ilness
  • Limited physical activity
  • Lack of insulin
  • Certain medications: corticosteroids, octreotide, beta blockers, epinephrine, thiazide diuretics, statins, protease inhibitors, antipsychotic medications
  • Excess cortisol, catecholamines, growth hormone, glucagon

Hyperglycemia may also be seen in:



  • Fasting glucose tests
  • Glucose tolerance tests
  • A1c test


See also diabetes mellitus type 2

Preoperative management

  • Consider:
    • Increased rates of infection
    • Medical complications including: acute kidney injury, acute coronary syndromes, and acute cerebrovascular events
  • Administer longer-acting analogs and the increased or continuous subcutaneous insulin infusion to cover the fasting period

Perioperative glycemic control

  • As long as HBA1c < 8.5%, no extra precautions are warranted, except to perform regular capillary blood glucose (CBG) measurements 
  • Administer simultaneously glucose with premixed potassium at a fixed rate and an i.v. insulin infusion titrated according to the CBG ( variable rate IV insulin infusion)
  • Treat a CBG > 12.0 mmol/L
  • Check capillary ketones to ensure that the patient had not developed DKA

Example of variable rate continuous insulin infusion:

Blood Glucose
mg/dL (mmol/L)
If BG increased from previous measurement
BG decreased from prior
measurement by less than 30mg/dL
BG decreased from prior
measurement by greater than 30mg/dL
> 241 (13.4) Increase rate by 3U/hIncrease rate by 3U/hNo change in rate
211-240 (11.7-13.4)Increase rate by 2U/hIncrease rate by 2U/hNo change in rate
181-210 (10-11.7) Increase rate by 1U/hIncrease rate by 1U/hNo change in rate
141-180 (7.8-10)No change in rate
No change in rate
No change in rate
110-140 (6.1-7.8)No change in rate
Decrease rate by ½ U/h Hold insulin infusion
100-109 (5.5-6.1) 1. Hold insulin infusion
2. Re-check BG hourly
3. Restart infusion at ½ the prior infusion rate if BG > 180mg/dL (10mmol/L)
71-99 (3.9-5.5)1. Hold insulin infusion
2. Check BG every 30 minutes until BG > 100mg/dL (5.5mmol/L)
3. Resume BG checks every hour
4. Restart infusion at ½ the prior infusion rate if BG > 180mg/dL (10mmol/L)
70 (3.9) or lowerIf BG 50-70 (2.8-3.9mmol/L),
1. Give 25mL D50
2. Repeat BG checks every 30 minutes until BG > 100mg/dL (5.5mmol/L)
If BG < 50mg/dL (2.8mmol/L)
1. Give 50mL D50
2. Repeat BG every 15 minutes until > 70mg/dL (3.9mmol/L)
3. When BG > 70mg/dL, BG checks every 30 minutes until > 100mg/dL (5.5mmol/L). Repeat 50mL D50 dose if
BG < 50mg/dL a second time and start D10 infusion.
4. After BG > 100mg/dL (5.5mmol/L), resume hourly BG check
Restart infusion at ½ the prior infusion rate if BG > 180mg/dL (5.5mmol/L)
BG: Blood Glucose, mg: milligrams, dL: deciliter, mmol: millimoles, L: liter, U: Units, h: hour, D50: 50% dextrose solution, D10: 10% dextrose
solution, mL: milliliters
1. If BG > 180mg/dL (10mmol/L), start insulin infusion
2. Consider bolus dose [BG – 100/40]
3. Start rate at BG/100 = U/hr
4. Check BG hourly and correct per table

Suggested reading

  • Duggan EW, Carlson K, Umpierrez GE. Perioperative Hyperglycemia Management: an update. Anesthesiology. 2017;126(3):547-560.
  • Stubbs, D.J., Levy, N., Dhatariya, K., 2017. The rationale and the strategies to achieve perioperative glycaemic control. BJA Education 17, 185–193.

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