What is the Hyperosmolar Hyperglycemic State (HHS) protocol?

From the Guidelines

The HHS protocol involves aggressive fluid resuscitation and insulin administration, with a focus on correcting dehydration, hyperglycemia, and electrolyte imbalances, as outlined in the most recent guidelines from 2025 1. The protocol typically starts with 0.9% NaCl or other crystalloid at a clinically appropriate rate, aiming to replace 50% of the estimated fluid deficit in the first 8-12 hours.

• Insulin administration is crucial, with a recommended dose of 0.05 units/kg/h i.v. insulin, and potassium replacement is essential to maintain serum potassium levels between 4 and 5 mmol/L.
• The goal is to keep glucose between 150 and 200 mg/dL until resolution, and to monitor electrolytes, renal function, venous pH, osmolality, and glucose every 2-4 hours until stable.
• It is also important to identify and treat the underlying cause of HHS, which can include infections, stroke, or medication non-compliance, as noted in previous guidelines 1 and studies 1.
• The management of HHS requires careful attention to fluid and electrolyte balance, as well as glucose control, to prevent complications and improve outcomes.
• Regular monitoring and adjustments to the treatment plan are necessary to ensure optimal care and minimize the risk of morbidity and mortality.

From the Research

HHS Protocol Overview

• Hyperosmolar Hyperglycaemic State (HHS) is a medical emergency that requires prompt treatment, with a higher mortality rate than diabetic ketoacidosis (DKA) 2.
• The key points in HHS guidelines include monitoring of the response to treatment, fluid and insulin administration, and delivery of care 2, 3.

Monitoring and Treatment

• Monitoring of the response to treatment involves measuring or calculating the serum osmolality regularly to monitor the response to treatment, and aiming to reduce osmolality by 3-8 mOsm/kg/h 2, 3.
• Fluid administration involves using i.v. 0.9% sodium chloride solution as the principal fluid to restore circulating volume and reverse dehydration 2, 4, 3, 5.
• Insulin administration involves withholding insulin until the blood glucose level is no longer falling with i.v. fluids alone (unless ketonaemic), and using a fixed rate intravenous insulin infusion (FRIII) once osmolality stops falling with fluid replacement 2, 3.

Delivery of Care

• The diabetes specialist team should be involved as soon as possible, and patients should be nursed in areas where staff are experienced in the management of HHS 2, 3.
• Identification and treatment of underlying and precipitating causes are necessary, and patients should be monitored closely to avoid overcorrection of osmolality, sodium, and other electrolytes 4, 6, 3, 5.

Specific Treatment Recommendations

• Adults should receive an average of 9 L of 0.9% saline over 48 hours, and potassium replacement should begin after urine output is established 4, 5.
• Children and adolescents should have dehydration corrected at a rate of no more than 3 mOsm per hour to avoid cerebral edema 5.
• HHS resolution criteria include osmolality <300 mOsm/kg, hypovolaemia corrected, cognitive status returned to pre-morbid state, and blood glucose <15 mmol/L 3.