In an unconscious adult with a capillary glucose ≤4 mmol/L who cannot take oral glucose, what rapid intravenous bolus of 40% dextrose (dose, volume, and administration time) is recommended and how should it be followed up?

40% Dextrose Infusion for Hypoglycemia in Unconscious Adults

Critical Note on 40% Dextrose

40% dextrose is not a standard concentration used in clinical practice and is not mentioned in any current guidelines or research evidence. The standard concentrations for intravenous hypoglycemia treatment are 10%, 25%, and 50% dextrose solutions 1, 2, 3.

Recommended IV Dextrose Protocol for Unconscious Adults

For an unconscious adult with glucose ≤4 mmol/L (≤70 mg/dL), administer 10-15 grams of dextrose intravenously as the initial bolus, using either 10% dextrose (100-150 mL) or 50% dextrose (20-30 mL), given over 1-3 minutes, followed by repeat glucose measurement at 5-10 minutes and additional 5-10 gram aliquots as needed until consciousness returns. 1, 4, 2, 3

Initial Bolus Dosing

Preferred approach using 10% dextrose:

• Administer 100 mL of 10% dextrose (10 grams) IV over 1-3 minutes 2, 3
• This delivers adequate glucose while minimizing risk of rebound hyperglycemia 3
• Median post-treatment glucose levels are significantly lower (6.2 mmol/L) compared to 50% dextrose (9.4 mmol/L) 3

Alternative using 50% dextrose:

• Administer 20-30 mL of 50% dextrose (10-15 grams) IV over 1-3 minutes 2
• Traditional approach but associated with higher post-treatment glucose levels 3
• Theoretical risks include extravasation injury and direct toxic effects of hypertonic solution 5

Repeat Dosing Algorithm

1. Check capillary glucose at 5-10 minutes after initial bolus 4, 2
2. If GCS remains <15 or glucose <4 mmol/L: Give additional 5-10 gram aliquots (50-100 mL of 10% or 10-20 mL of 50%) 2, 3
3. Repeat glucose checks every 5-10 minutes until patient achieves GCS of 15 2, 3
4. Maximum total dose typically 25 grams, though 18% of patients may require additional dosing 2, 5, 3

Expected Response Timeline

• Median time to achieve GCS of 15: 6-8 minutes after initial dextrose administration 2, 5
• No significant difference in recovery time between 10%, 25%, or 50% dextrose concentrations 2
• Approximately 18% of patients require a second dose due to persistent or recurrent hypoglycemia 5

Follow-Up Management

Immediate Post-Recovery (First Hour)

Once consciousness returns:

• Transition to oral glucose (15-20 grams) if patient can safely swallow 1, 4
• Examples: glucose tablets, 6-8 oz juice, 1 tablespoon honey 1
• Continue glucose monitoring every 1-2 hours for at least 4 hours 4, 6

Ongoing Monitoring

• Check glucose every 1-2 hours until stable and patient has resumed normal eating 4, 6
• Activate EMS if: patient has seizure, does not improve within 10 minutes of treatment, or experiences recurrent hypoglycemia 1
• Investigate precipitating cause: medication error, missed meal, excessive insulin, alcohol, sepsis 4, 6

Critical Pitfalls to Avoid

Never administer oral glucose to unconscious patients - this creates aspiration risk and is contraindicated 1

Do not delay IV dextrose administration - untreated hypoglycemia causes seizures, permanent brain injury, and death 1

Avoid excessive dextrose boluses - giving the full 25 grams upfront (50 mL of 50% dextrose) results in unnecessary hyperglycemia; titrated 5-10 gram aliquots are more physiologic 2, 3

Do not assume single dose is sufficient - 18% of patients require repeat dosing, so continued monitoring is essential 5

Check for underlying causes - recurrent hypoglycemia within 24 hours occurs in approximately 15% of cases and requires investigation 3

Special Considerations

If 40% Dextrose Is the Only Available Concentration

If you are in a setting where only 40% dextrose is available (non-standard):

• Calculate volume to deliver 10-15 grams: 25-37.5 mL of 40% dextrose
• Administer over 1-3 minutes using the same titration approach
• Follow the same monitoring and repeat dosing algorithm as outlined above

Advantages of 10% Dextrose Over 50% Dextrose

• Lower total dose required (median 10g vs 25g) to achieve recovery 3
• Lower post-treatment glucose levels (6.2 vs 9.4 mmol/L), reducing rebound hyperglycemia 3
• Equal efficacy in time to recovery (no difference in median time to GCS 15) 2, 3
• Reduced risk of extravasation injury and osmotic complications 5, 3
• More practical in settings with frequent D50 shortages 5