Management of DKA with Concurrent Alkalosis
When DKA presents with a mixed hypochloremic metabolic alkalosis (up to 30% of cases), use the standard DKA insulin infusion protocol with aggressive fluid resuscitation—the simultaneous fluid and electrolyte management will correct both the ketoacidosis and the alkalosis without requiring separate interventions. 1
Recognition and Diagnosis
Mixed DKA with alkalosis is identified by an elevated delta-delta gradient (ΔAG-ΔHCO₃) ≥5 mmol/L and base excess chloride (BECl) >2.7 mmol/L, indicating a concurrent hypochloremic metabolic alkalosis superimposed on the ketoacidosis. 1
This presentation can also manifest as combined metabolic and respiratory alkalosis with hypothermia and hypokalemia, though this is uncommon. 2
Initial laboratory evaluation should include plasma glucose, electrolytes with calculated anion gap, arterial or venous blood gases, serum ketones, and osmolality to characterize the mixed acid-base disorder. 3
Fluid Resuscitation Strategy
Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour to restore intravascular volume and renal perfusion, regardless of the presence of alkalosis. 4, 5
After the initial hour, switch to 0.45% NaCl at 4-14 mL/kg/hour if corrected serum sodium is normal or elevated; continue 0.9% NaCl if corrected sodium is low. 4, 5
The aggressive fluid resuscitation with chloride-containing solutions will simultaneously correct the hypochloremic alkalosis while treating the DKA—no separate alkalosis-specific interventions are needed. 1
Insulin Therapy
Start continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus to avoid precipitating cerebral edema and worsening hypokalemia. 3, 4
Expect a delayed recovery of hyperglycemia in mixed DKA with alkalosis (approximately 7 hours vs. 4.5 hours in pure DKA) due to higher initial glucose levels, not the alkalosis itself. 1
When glucose falls to 150-200 mg/dL, add dextrose-containing fluids (5% dextrose with 0.45-0.75% NaCl) but never interrupt insulin infusion—continue until complete resolution of ketoacidosis. 4
Critical Potassium Management
**If initial potassium is <3.3 mEq/L, DELAY insulin therapy** until potassium is repleted to >3.3 mEq/L to prevent life-threatening arrhythmias and cardiac arrest—this is especially critical in mixed presentations where hypokalemia may be more severe. 4, 2
Once K⁺ is <5.5 mEq/L and renal function is assured, add 20-40 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO₄), targeting serum potassium 4-5 mEq/L throughout treatment. 4, 3
Monitor potassium closely as insulin therapy will drive potassium intracellularly, potentially unmasking severe depletion and leading to complications including rhabdomyolysis. 2
Bicarbonate Therapy: Generally Contraindicated
Do NOT administer bicarbonate in mixed DKA with alkalosis—the alkalotic component makes bicarbonate therapy even more inappropriate than in pure DKA. 6
Bicarbonate use is generally not recommended even in pure DKA with pH >6.9, as studies show no benefit on clinical outcomes and potential harm (worsening ketosis, hypokalemia, cerebral edema risk). 3, 4
Consider bicarbonate only if pH <6.9 in pure DKA: give 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/h—this threshold does not apply to mixed presentations with alkalosis. 6, 4
Monitoring Protocol
Check blood glucose every 1-2 hours and draw blood every 2-4 hours for electrolytes, glucose, BUN, creatinine, osmolality, and venous pH. 4, 5
Monitor both anion gap closure (for ketoacidosis resolution) and base excess chloride (for alkalosis correction)—both should normalize with standard DKA management. 1
Venous pH (typically 0.03 units lower than arterial pH) can be followed instead of repeated arterial blood gases. 3, 4
Resolution Criteria and Transition
DKA is resolved when all of the following are met: glucose <200 mg/dL, bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L. 3, 4
There is no difference in time to anion gap closure between pure DKA and mixed DKA with alkalosis when using standard insulin infusion protocols. 1
Administer subcutaneous basal insulin (intermediate or long-acting) 2-4 hours BEFORE stopping IV insulin to prevent rebound ketoacidosis and hyperglycemia. 3, 4
Common Pitfalls to Avoid
Do not use hypotonic fluids too aggressively in mixed presentations, as this can lower serum osmolality faster than desired and increase cerebral edema risk, especially in younger patients. 7
Do not assume the alkalosis requires separate treatment—the standard DKA protocol with chloride-containing fluids and insulin will correct both disorders simultaneously. 1
Do not overlook severe hypokalemia masked by acidosis—mixed presentations may have more profound total body potassium depletion that becomes evident with insulin therapy. 2
In adult patients with mixed features, fluids may be administered more rapidly than in pure DKA because the risk for fatal cerebral edema in adults is low, but in younger patients, avoid rapid correction to minimize cerebral edema risk. 8