Type 1 Diabetes - Insulin dependent - High-risk of hypoglycaemia

Guidance for medical examiners when assessing a patient for either a general topic or condition - hypoglycaemia.

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Definition

This guidance should be used for applicants with type 1 diabetes using insulin.

Aeromedical implications

Effect of aviation on condition

  • Difficulty with regular blood-sugar monitoring
  • Irregular meal and sleep times
  • Sedentary occupation
  • Access to emergency treatment (e.g. glucose and glucagon)

Effect of condition on aviation

  • Overt incapacitation
    • Cardiovascular event
    • Cerebrovascular event
  • Subtle incapacitation - end-organ damage
    • Visual impairment (fields, low contrast sensitivity, colour)
    • Impaired motor and sensory nerve function
    • Impaired autonomic function (hypoglycaemia awareness).

Effect of treatment on aviation

  • Loss of consciousness due to hypoglycaemic event

Approach to medical certification - 2 stages

Diabetes treated with insulin does not meet the medical standards. However Class 2 applicants may be considered as follows:

  1. Initial certification with a safety pilot if they are able to comply with following Type 1 Diabetes protocol, for a minimum of 15 flights (details of types of flights and durations will be tailored by CASA to meet individual requirements)

    Based on the condition

    • Confirmed diagnosis
    • Absence of complications of diabetes (eye, heart, brain, kidney)
    • Hypoglycaemia awareness and absence of autonomic neuropathy
    • Completion of diabetes awareness education
    • Confirmed ability to self-monitor accurately

    Based on the condition

    • Diet
    • Insulin dose
    • Absence of significant side effects
    • Confirmed ability to determine and administer insulin doses

    Demonstrated stability

    • HbA1c 6.5 - 8.0% [47.5 - 60mmol/mol] : 2 readings at least 90 days apart
    • Record of blood sugar stability
    • No hypoglycaemic episodes within previous 12 months

    Demonstration of ability to manage diabetes in operational setting with safety pilot. CASA requires a report from a flight instructor that you are able to comply with the in-flight monitoring requirements. See Schedule Type 1 Diabetes

  2. To have the safety pilot requirement removed, the applicant must carry out the specified in-flight requirements as above and provide the on-ground and in-flight data to CASA for assessment and consideration. The ongoing requirements for any subsequent certification are as follows:
    • two whole blood glucose measuring devices must be carried and used
    • grounding and reporting to CASA immediately of
    • grounding and reporting to CASA immediately of
      • any hypoglycaemic incidents requiring external assistance
      • any involvement in accidents resulting in serious injury (whether or not related to hypoglycaemia)
      • any evidence of loss of control of diabetes, change in treatment regimen, or significant diabetic complications
    • endocrinologist’s report at 3-monthly intervals. Information required is listed below. If there is no change to status or control of diabetes, these reports may be accumulated and submitted annually with the next medical application. With any change, the applicant MUST ground themselves and await clearance from CASA
    • Renewal of Medical Certificate.

Risk assessment protocol - information required

New cases

  • Treating doctor report (GP or Endocrinologist) detailing:
    • current status of diabetes
    • episodes of symptomatic or biochemical hypoglycaemia / hyperglycaemia in the preceding 12 months and treatment required
    • assessment of control, HbA1c and glucose monitoring diary
    • evidence of end-organ damage (kidneys / eyes / erectile dysfunction). Cardiac assessment will be required separately
    • autonomic dysfunction assessment(1) (e.g. Ewing’s criteria)
    • Hypoglycaemia awareness
    • treatment protocol
    • confirmed ability to self-monitor accurately
    • confirmed ability to determine and administer insulin doses
    • follow-up recommendation
  • A report from an Ophthalmologist or Optometrist detailing:
    • visual acuity (with and without correction)
    • Retinal disease
    • pressures (and treatment if required)
    • any other ophthalmic pathology (fields / contrast sensitivity / colour vision)
  • An assessment by the DAME of the cardiac risk index. IF more than 14, a report from a Cardiologist with respect to:
    • any confirmed diagnosis
    • clinical status including any symptoms
    • investigations conducted including the results of a recent stress test
    • management:
      • control of risk factors
      • treatment and any side-effects
      • monitoring
      • risk of any acutely disabling cardiovascular event
  • Certification of completion of a diabetic counselling course from a diabetes educator
  • Glucose monitoring diary or printout. Electronic reporting criteria are:
  • Percentage of readings from 5.0 - 15.0mmol/L (inclusive)
  • Percentage of readings below 4.0mmol/L.

Renewal

Class 2: 12 monthly reports. Eye report 24-monthly unless end-organ damage evident.

  • Treating doctor report (GP or Endocrinologist) detailing:
    • current status of diabetes
    • episodes of symptomatic or biochemical hypoglycaemia / hyperglycaemia in the preceding 12 months and treatment required
    • assessment of control, HbA1c and glucose monitoring diary
    • evidence of end-organ damage (kidneys / eyes / erectile dysfunction). Cardiac assessment will be required separately
    • autonomic dysfunction assessment(1) (e.g. Ewing’s criteria)
    • Hypoglycaemia awareness
    • treatment protocol
    • confirmed ability to self-monitor accurately
    • confirmed ability to determine and administer insulin doses
    • follow-up recommendation
  • A report from an Ophthalmologist or Optometrist detailing:
    • visual acuity (with and without correction)
    • Retinal disease
    • pressures (and treatment if required)
    • any other ophthalmic pathology (fields / contrast sensitivity / colour vision)
  • An assessment by the DAME of the cardiac risk index. IF more than 14, a report from a Cardiologist with respect to:
    • any confirmed diagnosis
    • clinical status including any symptoms
    • investigations conducted including the results of a recent stress test
    • management:
      • control of risk factors
      • treatment and any side-effects
      • monitoring
      • risk of any acutely disabling cardiovascular event
  • Glucose monitoring diary or printout. Electronic reporting criteria are:
    • Percentage of readings from 5.0 - 15.0mmol/L (inclusive)
    • Percentage of readings below 4.0mmol/L
  • The record of all in-flight measurements and log book entries for all flights undertaken since the previous certificate application.

Indicative outcomes

  • On diagnosis, DAME should inform CASA Aviation Medicine Section and advise applicant not to exercise the privileges of their licence until cleared to do so by CASA
  • Medical certification limited to 12 months duration, on a case by case basis, with restrictions and limitations reflecting the level of control and identified complications

Favourable

  • Absence of hypoglycaemic episodes
  • Absence of complications of diabetes
  • Satisfactory control of glucose
  • Complete and consistent personal glucose monitoring
  • Good understanding of personal management of diabetes

Unfavourable

  • Hypoglycaemia and hypoglycaemic unawareness
  • End-organ damage
  • Poor or unpredictable glucose control
  • Absent or inconsistent personal glucose monitoring.

Pilot information

  • Type 1 diabetes is an aeromedically significant medical condition. Pilots and controllers who have been diagnosed with Type 1 Diabetes are required to ground themselves and notify this condition to their DAME
  • The type 1 diabetes protocol is only applicable for Class 2 (private) pilots. Not all pilots may be able to satisfy the entry or ongoing requirements in the protocol
  • The short-term risk CASA is most concerned about is when the glucose is running low (hypoglycaemia). This may or may not be apparent to the person affected. This is similar in some ways to the effect of alcohol or hypoxia (low oxygen). The effect on performance becomes increasingly obvious to others, but the affected individual may make poor decisions and judgements without recognising the problem and taking appropriate action
  • The longer-term risks CASA is concerned about include the effects that the condition has on the heart, eye and brain. Specific tests are needed to check these out
  • High blood sugars begin to cause more immediate problems when over 15mmol/L, especially with vision. Long-term elevated blood glucose is also known to increase the risk of the complications of diabetes
  • There is a major difference in the risk of hypoglycaemia occurring in type 1 diabetics (i.e insulin-dependent) and type 2 diabetics who are using insulin (i.e. insulin-requiring). The residual beta-cell function in the pancreas of type 2 diabetics means that severe hypoglycaemic episodes are less likely. This explains some of the apparent differences in policy around the world
  • When hypoglycaemic medication is changed, or when the dosage is changed, applicants must not exercise the privileges of their medical certificate until cleared by their DAME

Schedule Type 1 Diabetes

Actions before undertaking any flight operations

To ensure safe flight, the insulin-using diabetic aviator must carry:

  • two recording devices during flight, preferably a Continuous Glucose Monitoring System and a back-up glucometer
  • adequate supplies to obtain blood samples
  • an amount of rapidly absorbable glucose in 15 gm portions, appropriate to the planned duration of the flight.

The aviator must discuss this protocol with his treating physician and obtain advice as to the best combination of food intake/ medication that will optimise the glycaemic control without adversely affecting safety.

Monitoring and actions required during flight operations

The following actions shall be taken in connection with flight operations:

  1. Flight should not commence within 90 minutes of the administration of insulin (either short or long acting types)
  2. One-half hour prior to flight, the aviator must measure the blood glucose concentration:
    • if the concentration is more than 15 mmols/l, the flight must be cancelled
    • if it is less than 5 mmol/l the individual must ingest an appropriate (not less than 15 gm) glucose snack and measure the glucose concentration one-half hour later. If the concentration is within 5-15 mmol/l, flight operations may be undertaken. If the blood glucose is less than 5 mmol/l, the process must be repeated; if over 15mmol/l, the flight must be cancelled
  3. 30 minutes into the flight, and at each successive hour of flight, and within one-half hour prior to landing, the aviator must measure his or her blood glucose concentration:
    • if the concentration is less than 5mmols/l, a 30 gm glucose snack must be ingested, and arrangements be made to land at the nearest suitable airport and may not resume flight until the glucose concentration can be maintained in the 5-15 mmols/l range
    • if the concentration is 5-15 mmol/l, no action is required
    • if the concentration is greater than 15 mmol/l, the aviator must land at the nearest suitable airport and may not resume flight until the glucose concentration can be maintained in the 5-15 mmols/l range (Please also note paragraph 1 above).

In respect of determining blood glucose concentrations during flight, the aviator must use judgment in deciding whether measuring concentrations or operational demands of the environment (e.g. adverse weather, etc.) should take priority. In cases where it is decided that operational demands take priority, the aviator must ingest 15 gm glucose snack and measure his or her blood glucose level 1 hour later. If measurement is not practical at that time, the aviator must ingest a 30 gm glucose snack and land at the nearest suitable airport so that a determination of the blood glucose concentration may be made.

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Disclaimer

The clinical practice guidelines is provided by way of guidance only and subject to the clinical practice guidelines disclaimer.

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