FLYING BC - March 2002
FLYING BC - March 2002
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WHEN ARE MEDICATIONS NEEDED
HYPOGLYCEMIA IS BAD NEWS FOR
THE DIABETIC PILOT
CAN DIABETIC PILOTS FLY?
TRANSPORT CANADA GUIDELINES FOR DM-II
Dr. Randy Knipping is an aviation medical examiner for Transport Canada and the U.S. Federal Aviation Administration. He is the chair of COPAís Medical Advisory Board, and has a special interest in the prevention of health problems in aviation and the rehabilitation of grounded pilots. His private practice is limited to aviation medicine, and he also practices emergency medicine at the Trillium Health Centre, one of the largest and busiest metropolitan emergency rooms in Canada.
(Reprinted with the permission of Dr. Randy Knipping)
Managing the multiple health risk factors associated with diabetes with nutrition, exercise and diabetic medica- tions alone may only moderately reduce the risk of stroke, heart attack, kidney disease and peripheral vascular disease. Treating other risk factors aggressively has been shown to significantly reduce complications in diabetics. Taking Aspirin 81 mg daily reduces the risk of heart attack by an additional 25-50 per cent and reduces the risk of stroke by one third. The cholesterol lowering statin drugs such as pravastatin, simvastatin and atorvastatin can substantially lower the risk of cardiac complications.
The anti-hypertensive drugs angiotensin- converting enzyme (ACE) inhibitors are proving to have exceptional benefits for diabetics by reducing the risks of heart attack, stroke, and death in people with diabetes and to delay the onset and progression of kidney disease by 30 to 60 per cent, even in patients without hypertension. ACE inhibitors may even help prevent or limit progression of foot ulcers and retinopathy.
Transport Canada guidelines for diabetic pilots are based on ensuring safety during flight and identifying and preventing serious complications that could lead to sudden incapacitation such as hypoglycemia, heart attack and stroke. Transport Canada has published the diabetic guidelines on their Website: www.tc.gc.ca and the specific target for the guidelines is: http:// www.tc.gc.ca/aviation/cam/tp13312-2/english/d iabetNon_E.htm.
Those applicants who can control their blood glucose by diet alone may be considered fit for all categories of licence, provided they have no cardiovascular, neurological, ophthalmological or renal complications of DM which could result in sudden or subtle incapacitation while exercising the privileges of their licence. Applicants who require oral hypoglycemic agents to control their blood glucose may
be considered for medical certification pro-
viding certain criteria can be met.
These criteria are:
= No episode of hypoglycemia requiring intervention by others in past 12 months
= The applicants must have taken the hypoglycemic agent for a minimum of six months (three months in the case of metformin and the thiolipinogones), and
For pilots, the best way to treat diabetes is to prevent it from developing by optimizing nutrition and physical fitness. Understanding and managing this disease requires considerable knowledge and effort on the part of the pilot-patient and all of the involved health care professionals. Once the diagnosis is established, diabetic education, excellent glycemic control and maximal health risk factor management is essential to prevent the development of complications and to ensure that you stay fit to fly.
Power walking, swimming, skating, roller blading, cross-country skiing, anything that gets your heart rate up and maintains it for about an hour four to five times a week stimulates your body to produce insulin receptors, increase cardiovascular reserve and make you feel better in your body and mind. Exercise reduces blood pressure, the negative biochemical effects of stress, body fat, and the risk of cardiovascular disease. In fact, even if you donít lose any weight during exercise, you still reduce your risk of diabetes and heart disease. Diabetics are at risk of losing their feet due to the vascular and neuropathic changes associated with diabetes. Preventive foot care could reduce the risk of amputation by 44 to 85 per cent. Patients inspect their feet daily and watch for changes in color or texture, odor, and firm or hardened areas, which may indicate infection and potential ulcers. A specialist in foot care should be consulted for any problems.
When optimizing nutrition and fitness does not result in fasting glucose < 6.9 mmol/L or a two-hour post prandial after eating) glucose of 11.1 mmol/L or a glycosylated hemoglobin of less than 7.5 per cent, then medication is generally indicated. However, the diabetic pilot has special needs in this regard because many of the commonly used diabetic drugs can cause hypoglycemia.
Hypoglycemia occurs when the blood glucose drops to below 4.0 mmol/L and results in decreased memory, concentration and attention. With rapid drops to below 2.0 mmol/L, the diabetic pilot can lose consciousness and in severe cases death can occur. Insidious hypoglycemia (developing gradually) is particularly dangerous since the pilot may not be aware of any symptoms before it is too late.
Therefore, the best diabetic medica- tions for pilots are those that do not cause significant hypoglycemia such as metformin and acarbose. Drugs such as glyburide, a sulphonylurea, can cause hypoglycemia and weight gain. It is best to discuss medication with a physician experienced in aviation medicine and diabetes management since there are a large number of new diabetic agents available and it is not possible to detail them in this article.
the dosage should have been stable for
at least three months.
= There must be evidence of stable blood glucose control for at least three months
as measured by: HgA1c patient/upper
normal ratio less than 2.0.
= Blood glucose metering shows 90 per cent of values greater than 5.5 mmol/L.
= No neurological, cardiovascular, ophthalmological or renal complications of DM that could result in sudden or subtle incapacitation while exercising the privileges of the licence.
= Blood glucose monitoring will be carried out using a memory chip glucose meter. This equipment together with a readily absorbable source of glucose will be carried by the applicant while exercising the privileges of the licence.
= A vision care specialist assessment is required on initial application and every year thereafter.
= A cardiovascular assessment to include an exercise electrocardiogram is required at the age of 40 and then five yearly to age 50. After the age of 50 it should be completed every two years. A resting ECG will be required yearly.
CAN COMPLICATIONS OF DIABETES BE PREVENTED THROUGH OTHER MEDICATIONS?