DKA & HHS

DKA — all three: D glucose ≥200 mg/dL (11.1 mmol/L) or a prior history of diabetes; K β-hydroxybutyrate ≥3.0 mmol/L or urine ketones ≥2+; A pH <7.3 and/or HCO₃⁻ <18 mmol/L. Euglycemic DKA = DKA with glucose <200 mg/dL (about 10% of cases; most now linked to SGLT2 inhibitors).

HHS — all four: glucose ≥600 mg/dL (33.3 mmol/L); calculated effective osmolality >300 mOsm/kg or total osmolality >320 mOsm/kg; β-OHB <3.0 mmol/L or urine ketones <2+; pH ≥7.3 and HCO₃⁻ ≥15 mmol/L.

Mixed DKA/HHS: HHS-range glucose and osmolality with significant ketonemia (β-OHB ≥3.0, ketonuria ≥2+) or acidosis. The consensus insulin section treats pH <7.30 or HCO₃⁻ <18 in HHS as significant — this tool therefore uses 0.1 U/kg/h whenever any of these is present, even if HCO₃⁻ is 15–17.9 and the Fig. 2 HHS criteria are still met.

The anion gap is not a first-line diagnostic or resolution criterion: about a third of patients have mixed acid–base disorders, and saline-driven hyperchloremia keeps the gap misleading during recovery.

Not every variable has to fit. This tool reports the most severe category that any entered variable reaches, after rounding pH to 2 decimals and HCO₃⁻ and β-OHB to 1 decimal. Severe DKA, HHS, mixed states, altered mental status or a critical precipitating illness → ICU.

Fluids: 0.9% NaCl or a balanced crystalloid (lactated Ringer's, Plasma-Lyte 148 — faster DKA resolution and less hyperchloremia in recent studies). Without cardiac or kidney compromise, 500–1000 mL/h for the first 2–4 h; Fig. 4 gives 1.0 L/h for severe hypovolemia and, for mild hypovolemia, a rate that replaces 50% of the estimated deficit in 8–12 h. Correct deficits over 24–48 h. Older adults, heart failure and dialysis: 250 mL boluses with frequent reassessment.

Potassium (after urine output ~0.5 mL/kg/h): K⁺ ≤3.5 → hold insulin, give 10–20 mmol/h until K⁺ is above 3.5 (text: 10 mmol/h; faster needs central access). Fig. 4 draws the bands as <3.5 and 3.5–5.0, but the text says to delay insulin until K⁺ >3.5; the tool follows the text and gates on the unrounded value. K⁺ >3.5–5.0 → 10–20 mmol per litre of fluid (text: 20–30 mmol/L suffices for most) to keep 4–5. K⁺ >5.0 → insulin, no K⁺, recheck every 2 h. Recheck K⁺ 2 h after insulin starts, then every 4 h.

Insulin: DKA moderate/severe — fixed-rate IV 0.1 U/kg/h (0.1 U/kg IV bolus only if the infusion will be delayed). Mild (and uncomplicated moderate) DKA — SC rapid-acting analog 0.1 U/kg, then 0.1 U/kg every 1 h or 0.2 U/kg every 2 h. HHS without significant ketonemia — 0.05 U/kg/h (some withhold insulin until glucose stops falling on fluids alone). Mixed — 0.1 U/kg/h.

Glucose <250 mg/dL (13.9): add 5% or 10% dextrose, cut insulin to 0.05 U/kg/h IV (SC: 0.05 U/kg hourly or 0.1 U/kg every 2 h). Keep glucose 150–200 mg/dL (8.3–11.0) in DKA, 200–250 mg/dL (11.0–13.9) in HHS. Euglycemic DKA: start dextrose with the insulin. The consensus gives no specific starting insulin rate for DKA that presents with glucose already <250 mg/dL; the tool shows the range 0.05–0.1 U/kg/h with dextrose.

Weight: doses are weight-based with no published maximum; above 150 kg the tool flags the rate for confirmation against local protocol. Weight is limited to 30–250 kg.

Bicarbonate only if pH <7.0: 100 mmol NaHCO₃ (8.4%) in 400 mL sterile water every 2 h until pH >7.0. Phosphate only with muscle weakness, respiratory or cardiac compromise and phosphate <1.0 mmol/L: 20–30 mmol potassium phosphate added to fluids.

HHS: glucose fall ≤90–120 mg/dL/h (5–6.7 mmol/L/h); Na⁺ fall ≤10 mmol/L in 24 h; osmolality fall 3–8 mOsm/kg/h. A rising Na⁺ early on is expected (≈1.6 mmol/L per 100 mg/dL glucose fall) and is not an indication for hypotonic fluid; use 0.45% NaCl only if osmolality stops falling despite positive fluid balance and adequate insulin.

DKA resolved: ketones <0.6 mmol/L and venous pH ≥7.3 or HCO₃⁻ ≥18 mmol/L; ideally glucose <200 mg/dL. Do not use the anion gap or urine ketones.

HHS resolved: measured or calculated osmolality <300 mOsm/kg, glucose <250 mg/dL, urine output >0.5 mL/kg/h and improved cognition.

Transition: start SC basal insulin 1–2 h before stopping the IV infusion (ADA 2026 Standards: 2 h). Total daily dose 0.5–0.6 U/kg/day if insulin-naive, ≈0.3 U/kg/day with hypoglycemia risk (frailty, CKD), or from the preadmission regimen or the stable IV requirement (e.g. last 6 h, which may overestimate). Give 40–60% as basal and split the rest over three meals; if NPO, basal plus correction every 4–6 h. Low-dose basal (0.15–0.3 U/kg) during the infusion shortens infusion time without more hypoglycemia. Do not restart SGLT2 inhibitors in hospital.