What are the standard orders for emergency department evaluation and initial management of an adult patient with suspected diabetic ketoacidosis?

Standard Orders for ER Evaluation of Suspected DKA

Immediately obtain a comprehensive metabolic panel, venous blood gas, serum ketones (β-hydroxybutyrate preferred), complete blood count, urinalysis with ketones, and ECG on presentation. 1, 2, 3

Initial Laboratory Workup

Essential Diagnostic Tests (Stat Orders)

• Plasma glucose – diagnostic threshold >250 mg/dL for classic DKA 1, 3
• Venous blood gas – arterial pH <7.3 (or venous pH which runs ~0.03 units lower) confirms acidosis; venous sampling is adequate after initial assessment 1, 3
• Serum electrolytes with calculated anion gap – anion gap = [Na⁺] - ([Cl⁻] + [HCO₃⁻]), should be >10-12 mEq/L in DKA 1, 3
• Serum bicarbonate – <15 mEq/L for mild DKA, <10 mEq/L for severe 1, 3
• Serum β-hydroxybutyrate – this is the preferred ketone test over nitroprusside-based urine or serum methods, which miss the predominant ketone body 1, 2, 3
• BUN and creatinine – assess renal function and hydration status 1, 2
• Serum osmolality – calculate effective osmolality as 2 × [Na] + glucose/18 1, 2
• Complete blood count with differential – evaluate for infection or leukocytosis from stress response 1, 2
• Urinalysis with urine ketones – though blood β-hydroxybutyrate is superior 1, 2
• Electrocardiogram – assess for cardiac ischemia as precipitant and monitor for hypokalemia effects 1, 2

Calculate Corrected Sodium

• Add 1.6 mEq/L to measured sodium for every 100 mg/dL glucose above 100 mg/dL – this corrected value guides subsequent fluid choice 1, 2

Additional Tests When Clinically Indicated

• Blood, urine, and throat cultures – if infection suspected as precipitating cause 1, 2
• Chest X-ray – only if respiratory symptoms or suspected pneumonia 2
• Troponin and creatine kinase – if myocardial infarction suspected 4
• Amylase and lipase – if abdominal pain suggests pancreatitis 4
• Hemoglobin A1c – distinguish acute versus chronic poor control 3

Immediate Management Orders (First Hour)

Fluid Resuscitation

Begin isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in average adult) during the first hour, regardless of corrected sodium. 1, 2

• This addresses the typical 6-9 L total body water deficit 1, 2
• Monitor closely for fluid overload in patients with cardiac or renal compromise 1, 2

Critical Safety Check Before Insulin

Check serum potassium BEFORE initiating insulin – this is an absolute contraindication threshold. 1, 2

• If K⁺ <3.3 mEq/L – HOLD insulin, aggressively replace potassium until ≥3.3 mEq/L to prevent fatal arrhythmias (Class A evidence) 1, 2
• If K⁺ 3.3-5.5 mEq/L – safe to start insulin; add 20-30 mEq/L potassium to IV fluids (2/3 KCl, 1/3 KPO₄) once urine output confirmed 1, 2
• If K⁺ >5.5 mEq/L – start insulin immediately, withhold potassium initially but monitor every 2-4 hours as levels will fall rapidly 1, 2

Insulin Therapy Protocol

For moderate-to-severe DKA or altered mental status: continuous IV regular insulin infusion at 0.1 units/kg/hour (optional 0.1 units/kg IV bolus first). 1, 2

• Prepare solution: 100 units regular insulin in 100 mL normal saline (1 unit/mL) 2
• Prime tubing with 20 mL of solution before connecting to patient 2
• Target glucose decline of 50-75 mg/dL per hour 1, 2
• If glucose does not fall ≥50 mg/dL in first hour despite adequate hydration, double insulin rate hourly until steady decline achieved 1, 2

Alternative for mild-moderate uncomplicated DKA in hemodynamically stable, alert patients: subcutaneous rapid-acting insulin analogs 0.1-0.2 units/kg every 1-2 hours combined with aggressive IV fluids. 1, 2

Ongoing Monitoring Orders

Laboratory Monitoring Frequency

Draw blood every 2-4 hours for:

• Serum glucose 1, 2
• Electrolytes (especially potassium) 1, 2
• Venous pH 1, 2
• Serum bicarbonate 1, 2
• Anion gap 1, 2
• BUN and creatinine 1, 2
• Serum osmolality 1, 2
• β-hydroxybutyrate (preferred over urine ketones for monitoring resolution) 1, 2

Bedside Glucose Monitoring

• Check capillary glucose every 1-2 hours during active insulin titration 2
• Protocols using 4-hourly checks are associated with hypoglycemia rates >10% and should be avoided 2

Fluid Management After First Hour

Subsequent fluid choice depends on corrected serum sodium:

• If corrected Na normal or elevated – switch to 0.45% NaCl at 4-14 mL/kg/hour 1, 2
• If corrected Na low – continue 0.9% NaCl at 4-14 mL/kg/hour 1, 2
• When glucose falls to 250 mg/dL – change to 5% dextrose with 0.45-0.75% NaCl while continuing insulin infusion to clear ketones 1, 2

Identification of Precipitating Cause

Concurrently investigate and treat underlying triggers:

• Infection (most common) – obtain cultures, start empiric antibiotics if indicated 1, 4
• Myocardial infarction – check troponin, ECG 1, 4
• Cerebrovascular accident – assess for focal neurological deficits 1
• Medication non-adherence – insulin omission or inadequacy 1
• SGLT2 inhibitor use – can cause euglycemic DKA; discontinue immediately 1, 5
• Pancreatitis – check lipase if abdominal pain present 1, 4
• Pregnancy – consider in women of childbearing age 1

Common Pitfalls to Avoid

• Never start insulin when K⁺ <3.3 mEq/L – this can cause fatal cardiac arrhythmias (Class A evidence) 1, 2
• Never stop insulin when glucose normalizes – ketoacidosis takes longer to resolve; instead add dextrose and continue insulin 1, 2
• Do not rely on urine ketones or nitroprusside methods – they miss β-hydroxybutyrate and can falsely suggest worsening during treatment 1, 3
• Do not use bicarbonate unless pH <6.9 – no benefit in resolution time, may worsen outcomes 1, 2
• Avoid overly rapid osmolality correction – limit change to ≤3 mOsm/kg/hour to reduce cerebral edema risk 1

DKA Resolution Criteria

All of the following must be met before transitioning care:

• Glucose <200 mg/dL 1, 3
• Serum bicarbonate ≥18 mEq/L 1, 3
• Venous pH >7.3 1, 3
• Anion gap ≤12 mEq/L 1, 3
• β-hydroxybutyrate <1.0 mmol/L (if measured) 2

Transition to Subcutaneous Insulin

Administer long-acting basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin infusion to prevent rebound hyperglycemia and recurrent DKA. 1, 2

• Continue IV insulin for 1-2 hours after subcutaneous dose to ensure absorption 1, 2
• Estimate basal dose as ~50% of total 24-hour IV insulin requirement 2