Insulin Dosing for Blood Glucose of 420 mg/dL
For a patient with a blood glucose of 420 mg/dL and a sliding scale that indicates 10 units of Humalog for blood glucose of 400 mg/dL, you should administer 10 units of Humalog (insulin lispro) immediately.
Rationale for Dosing Decision
The patient's blood glucose of 420 mg/dL falls just above the 400 mg/dL threshold on their sliding scale. According to standard sliding scale protocols:
- When a patient's blood glucose falls between two values on a sliding scale, you should administer the dose corresponding to the lower value 1
- The sliding scale indicates 10 units of Humalog for blood glucose of 400 mg/dL
- Since 420 mg/dL is only slightly above 400 mg/dL, the 10 unit dose is appropriate
Administration Considerations
- Humalog (insulin lispro) is a rapid-acting insulin with onset within 5 minutes, peak action at 1-2 hours, and duration of 3-4 hours 2
- For hyperglycemia management, Humalog should be administered immediately before or immediately after meals 3
- In the case of marked hyperglycemia (>250 mg/dL), administering Humalog 15 minutes before meals may provide better postprandial glucose control 4
Monitoring After Administration
After administering the insulin:
- Monitor blood glucose in 1-2 hours to assess the effectiveness of the dose
- For hospitalized patients with hyperglycemia, blood glucose monitoring should be performed every 4-6 hours 1
- Be alert for signs of hypoglycemia (blood glucose <70 mg/dL), which would require immediate intervention
Important Considerations
Avoid relying solely on sliding scale insulin: While addressing the immediate hyperglycemia, be aware that sliding scale insulin alone is not recommended as the sole treatment strategy for diabetes management in hospitalized patients 1
Consider basal-bolus regimen: For ongoing management, a basal-bolus insulin regimen is preferred over sliding scale alone, with approximately 50% of total daily insulin as basal insulin and 50% as prandial insulin 1
Assess for underlying causes: Severe hyperglycemia (>400 mg/dL) may indicate underlying issues that need addressing, such as infection, medication effects, or inadequate baseline insulin regimen
Document the intervention: Record the blood glucose value, insulin dose administered, time of administration, and plan for follow-up monitoring
Hypoglycemia Precautions
If hypoglycemia (<70 mg/dL) occurs after insulin administration:
- For mild-moderate hypoglycemia (40-70 mg/dL) in conscious patients: administer 15-20g oral carbohydrate
- For severe hypoglycemia (<40 mg/dL) or unconscious patients: administer IV dextrose 25g or glucagon 1mg IM/SC if IV access is unavailable
- Recheck blood glucose after 15 minutes and repeat treatment if necessary 1
Remember that Humalog has a rapid onset of action, so close monitoring after administration is essential, especially with high doses used to treat severe hyperglycemia.