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Hyperglycemia is defined as a blood glucose level greater than 200 mg/dL (11.1 mmol/L). An elevated glucose level alone does not represent a medical emergency. However, very high glucose levels and hyperglycemia in the setting of DKA are urgent medical problems that should be recognized and treated accordingly.

When DKA is treated properly, it rarely produces residual effects. Before the discovery of insulin in 1922, the mortality rate was 100%. Over the last three decades, DKA mortality rates have markedly decreased in developed countries, from 7.96% to 0.67% [35]. EMS clinicians encounter this condition predominantly in type 1 diabetics, but it may also rarely occur in type 2 diabetics dependent on daily insulin therapy to maintain glycemic control. DKA may be precipitated by metabolic stressors such as infectious processes, myocardial infarction, pregnancy, and trauma, especially if they interrupt the insulin regimen. Patients may present with nonspecific signs and symptoms that include fatigue, tachypnea, altered sensorium, abdominal pain, nausea, vomiting, polydipsia, and polyuria. They may also present with severe dehydration, hypotension, or “Kussmaul’s respirations” (deep, rapid respiration) as the body attempts to expire excess carbon dioxide to compensate for the metabolic acidosis [36].

Although little research has been dedicated to EMS treatment of DKA, most emergency medicine treatment modalities can apply out‐of‐hospital. Recognition and expeditious initiation of treatment are critical. IV fluid resuscitation should be started to correct volume depletion. These patients should be closely monitored. There is no role for insulin therapy in the prehospital setting. An important caveat relates to pediatric patients, for whom there is a risk of life‐threatening cerebral edema with rapid volume repletion. For children, insulin (at the hospital) plays a more critical early role, and initial resuscitation should only be intended to reverse appearance of shock or hypotension. Additional correction of a fluid deficit should occur over 24‐48 hours.

Patients with hyperglycemia may present with hyperosmolar hyperglycemic syndrome (HHS). HHS is a serious diabetic emergency with a mortality rate as high as 20%, about ten times higher than that of DKA [37]. While EMS clinicians may not be able to differentiate DKA from HHS, they may suspect it from the patient’s history. HHS is more common in patients with type 2 diabetes and is triggered by the same stressors that elicit DKA. Patients with HHS present with marked volume depletion, necessitating the initiation of intravenous fluid resuscitation without delay. Field treatment should be targeted to hemodynamic stabilization first. Fluid boluses should be given with continuous monitoring and frequent reassessment of vital signs.