There is no fixed NS volume or drip rate to give with “8 units plain insulin” for a high GRBS. Do not start an insulin-in-NS infusion based only on a glucose value.

IV regular insulin is used only under a monitored hospital protocol, after checking:

For DKA, protocols generally use a weight-based insulin infusion, not a fixed 8-unit dose, with isotonic fluid resuscitation tailored to the patient. The medical text notes that DKA insulin is administered as an infusion, commonly at 0.1 units/kg/hour under a hospital protocol (Miller's Anesthesia, 10e). The 2024 hyperglycemic-crises consensus report also emphasizes protocol-based evaluation and management.

If this is just an isolated high GRBS in a stable patient, use that patient’s prescribed subcutaneous correction scale and contact the treating clinician rather than giving IV insulin/drip.

Urgent referral / ER now if glucose is very high (especially >300 mg/dL or >16.7 mmol/L) with vomiting, abdominal pain, deep/rapid breathing, drowsiness, dehydration, fever/infection, positive urine/blood ketones, or inability to drink.

If you mean the drip calculation, the rate cannot be calculated without the prescribed total NS volume, intended duration, and IV set drop factor (for example, 15, 20, or 60 drops/mL).