February 1, 2012
by Joonyoung Ji, DMD
The prevalence of diabetes mellitus in the general populace continues to grow, and along with increasing life expectancy it can be expected that dentists will have an increasing proportion of diabetic patients. Data from Statistics Canada show in the period of 2009 to 2010, nearly 140,000 new cases of diabetes were diagnosed in Canada with Ontario responsible for 100,000. Diabetes is most prevalent in the 45+ age group and with the projected increase in the 65 and over age group to every one out of three Canadians by 2036, it is almost certain more of our patients will be diabetics. For the dentist using oral moderate sedation, diabetes presents an additional problem of potential preoperative and perioperative hypoglycaemia by iatrogenic intake restriction.1
In following the npo guidelines for oral moderate sedation with or without nitrous oxide as per the Royal College of Dental Surgeons of Ontario guidelines, diabetic patients with their impaired glucose regulation may be rendered hypoglycaemic. Although mild hypoglycaemia in itself is not a medical emergency, with progressing hypoglycaemia the patient can exhibit agitation, restlessness, diaphoresis, tachycardia, seizures, acidosis, unconsciousness, and coma.2,3 The signs and symptoms above may not even be present until severe hypoglycaemia in what’s known as “hypoglycaemia unawareness”.4
In managing the npo status for the diabetic patient, several precautions or modifications can be tailored for the patient. A commonly used option is a short, morning appointment with restriction of oral hypoglycaemic agents until after the sedation appointment. An additional precaution that can be taken is a simple blood sugar check with a glucometer and evaluation of the patient’s own compliance and monitoring. Fasting glucose levels of approximately 4 to 6 mmol/L indicates control and it can be expected to decrease over the duration of the appointment5. However, emergencies are usually multifactorial and unfortunately are not completely preventable using this measure alone.
Management for the conscious hypoglycaemic patient is straightforward as long as the signs and symptoms are identified; administer a source of glucose. What if though, the patient is unconscious and hypoglycaemic? Due to potential airway complications such as laryngospasm, a per oralis administration of any kind is contraindicated. Since excess secretions can cause airway compromise in an unconscious patient, even mucosal application of a viscous source of sugar may not be a good idea.
Administration of glucagon in the situation of an unconscious hypoglycaemic patient would be of value. It can be administered as a single, intramuscular dose of 1 mg without serious adverse effects. Its action is to promote gluconeogenesis, increasing blood sugar levels without the use of exogenous sources of sugar. It is supplied as a 1 mg (1 unit) injection kit, requiring reconstitution before use6. It is not a permanent solution but used as a bridge, it will bring an unconscious hypoglycaemic back to consciousness, so that an oral administration of a sugar source is safe to consume.6
The RCDSO’s minimal mandatory emergency drug list for oral sedation includes 8 items: oxygen; epinephrine; nitroglycerin; a parenteral antihistamine; a bronchodilator; flumazenil; naloxone; and acetylsalicylic acid. Of the above drugs, none would be particularly helpful for the unconscious hypoglycaemic patient. Currently, fruit juice or sugar tablets are the primary glucose source in the dental emergency kit with glucagon being an optional drug. Considering that a hypoglycaemic patient may deteriorate and lose consciousness, having glucagon available can potentially help in this type of medical emergency.
Gaining and maintaining public trust includes effective prevention and management of emergencies. Although rare and undesirable, medical emergencies do occur even with proper precautionary steps. With the combination of the npo guidelines for oral moderate sedation and the increasing prevalence of diabetes, it may be wise to add glucagon to the emergency kit armamentarium. OH
Joonyoung Ji is a DMD from the University of Saskatchewan and a first-year resident in the postgraduate Dental Anaesthesia program at the University of Toronto.
Oral Health welcomes this original article.
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5. Holman RR, Paul SK, Bethel MA, Matthews DR, Neil HA. 10-year follow-up of intensive glucose control in type 2 diabetes. N Engl J Med 2008; 359: 1577-1589.
6. Glucagon [package insert]. Indianapolis, IN: Eli Lilly & Co; 2011.