It appears to be common practice in many EMS systems for providers to obtain a blood glucose level on virtually every patient during initial assessment. Many would consider a blood glucose level as the fifth vital sign after blood pressure, pulse rate, respiratory rate and SpO2. The blood glucose level is often obtained at the time of an IV catheter placement. For the most part, blood glucose levels are normal. Thus, one must ask why do we measure a blood glucose level in virtually all prehospital patients?
In patients with diabetes, hypoglycemia can have serious deleterious effects. Generally speaking, hypoglycemia is defined as a blood glucose reading of less than 55-60 mg/dL (3.1-3.3 mmol/L). Patients with diabetes who have taken an excessive amount of insulin, or taken a standard amount of insulin but failed to ingest an adequate number of calories, can develop hypoglycemia.
This can cause numerous side effects including altered mental status, weakness, sweet enough, nausea, vomiting and even unconsciousness. Hypoglycemia is more common in Type 1 diabetes (which requires use of insulin) than Type 2 diabetes where patients augment their oral diabetic agents with insulin. Once detected, the condition can be treated with intravenous glucose, oral glucose or the injection of glucagon.