Dr Fabian Yap, Paediatric Endocrinologist, Endocrinology Service, KK Women's and Children's Hospital, zooms in on the finer points of flying high and making family vacations fun and enjoyable for all.

Introduction
Outbound vacation travel has become an integral part of Singaporean lifestyle. In a recent travel survey, 96% of Singaporeans indicated that they would make a leisure trip to an international destination in the next 12 months. Although vacations are supposed to be time for relaxation, normal routines are interrupted and our bodies are forced to adapt to a wide array of changes.

In contrast, optimal diabetes management stresses on the importance of routines (blood sugar testing, insulin injections) and discipline (regular meals, portion sizing). These goals are near impossible to achieve even for a travelling adult diabetic, let alone a child. Additionally, it is well known that young children become more irritable when their routines are interrupted, making diabetes management even more difficult

It is therefore important for families who intend to travel with insulin-dependent diabetic children to understand how vacationing can influence their child's blood sugar control and how to prepare for these changes.

Characteristics of travel that may influence blood sugar control
 

General considerations

When travelling to a new destination, there is excitement, a sense of anticipation. emotions that can heighten the body's stress responses. This may cause the body to produce hormones such as adrenaline and cortisol that act to increase blood sugar levels. On the other hand, increased physical activity may cause the body to consume more sugar, resulting in lower blood sugar levels.

Food consumption is an important variable that must be taken into consideration. A new and foreign destination may offer a food range that the diabetic child is unaccustomed to. This may lead parents to compromise on food choices for their children. Particularly fussy eaters may find it difficult to adapt to local foods and opt to have their meals at familiar fast food outlets.

Therefore, expect erratic blood glucose reading when on holiday. Be aware if your child is eating more or less, adjust insulin doses or control the intake accordingly.

Effects of the physical environment
When travelling, it is important that insulin is carefully stored, as frozen insulin or insulin left exposed to significant heat will be denatured, causing it to lose its effect completely. Damaged insulin will turn cloudy, floccular or brownish. Therefore, the ambient temperature of a travel destination must be considered as it may indirectly influence the blood sugar levels. Take note that absorption of insulin will be reduced at injection sites exposed to the low temperatures due to decreased blood flow to cold skin.

It is also wise to consider the state of development of the travel destination carefully. The likelihood of acquiring gastrointestinal disease is higher in non-urban, underdeveloped surroundings with poor sewerage systems. For the novice diabetic traveller, it may be wiser to gain travel experience first in a city setting because the likelihood of developing an illness is lower and medical help is easily accessed when needed. You may also want to ask your doctor to identify an appropriate hospital at your travel destination just in case there is an emergency.

Time zones and flight duration
The impact of time zones on insulin regimens presents the greatest challenge to parents with diabetic children. Time is "lost" with eastward travel for example, Singapore to Sydney or New Zealand; while time is "gained" with westward travel, such as for trips to Europe, the Middle East or to the Indian sub-continent. This may confuse many families who often call up their doctor or specialist diabetes nurse for last minute advice on how to make adjustments to their insulin regimen. It is important to remember that time zone change must be considered together with flight duration to be meaningful.

For example, the duration of a flight from Singapore to Sydney lasts eight hours and there is a time difference of three hours. If the flight departs Singapore at 0800h, it will arrive in Sydney at I 900h (0900h plus eight hours plus three hours). Because travel to Sydney is eastwards, three hours are lost. In contrast the return flight from Sydney to Singapore is westward and three hours should be gained. If the flight departs Sydney at 0800h. it will arrive in Singapore at 1300h (O800h plus eight hours minus three hours). The determination of departure and arrival time is crucial in planning an insulin regimen.

In general, the shorter the flight and the more similar the time zone of the destination, adjustment of the existing insulin regimen is less likely. From a practical viewpoint, no adjustment Is needed for travel to ASEAN countries, as these countries are only a short flight away. Adjustment is also not needed for travel to Western Australia, China, Japan and Korea, as these countries are within one hour of Singapore's time zone.

However, those travelling beyond a two-hour time zone, such as those travelling to the Indian sub-continent, Eastern Australia, New Zealand, the Middle East, Africa, Europe and the Americas ought to consult their doctor for an insulin plan.

Things to do before travelling
Be aware of your child's blood glucose control before travelling. Children with poor control, such as those with HbA1c readings above 9% or repeated hospital admissions, are at greater risk of developing hypoglycaemia (very low blood glucose) or hyperglycaemia (very high blood glucose) as well as diabetic ketoacidosis (DKA). It is always best to optimise blood glucose control prior to travel.

Choose your travel or holiday destination carefully. Places with proper sanitation facilities, clean food and accessible health care are ideal travel destinations. Families travelling with diabetic children for the first time ought to avoid being overly ambitious. City or resort holidays will be ideal starting destinations. Novice travellers are discouraged from attempting anything too strenuous such as mountain trekking or long cycling expedition's as special preparations are necessary in such circumstances. Choose sensible activities within your capabilities.

In view of the high likelihood of encountering blood glucose swings during travel, it is recommended that families revise hypoglycaemia and hyperglycaemia management. Those with diabetes management manuals should take them along and be adequately equipped with supplies needed during such situations. Bring along a "hypo kit". Don't forget to bring your supplies for urine or blood ketone testing, as this may be needed if your child falls sick and develops hyperglycaemia.

It will be useful to have a letter for the customs officer at the airport informing of your child's diabetic condition and the need for needles, pens, syringes, insulin, glucagon and glucose meters. This letter can be obtained from your diabetes care provider. Finally, please prepare an insulin regimen plan for the trip, which should include a plan for the flight to and from your travel destination.

Insulin regimen plans
The basis of formulating an insulin plan is to ensure that there is adequate insulin (to prevent hyperglycaemia and ketosis) for the body throughout the flight, while at the same time avoiding hypoglycaemia (which may be a sign of insulin excess). Many variables are considered such as the number of injections a day, the type of long acting insulin used, flight departure and arrival times and the flight duration. The best plan is the safest and least confusing for the patient and family.

Let us consider the example of a child who is on twice-daily insulin, that is combined Actrapid and Insulatard pre-breakfast and pre-dinner, who is on a return trip to London.

Singapore to London return

The trip to London begins with a 0900h flight from Changi airport. Bearing in mind that there is an 8-hour time difference and that this direct flight lasts approximately 14 hours, one would expect to arrive at about 1500h in the afternoon, London time, The plan can be as follows:

Administer Actrapid and Insulatard pre-breakfast (have breakfast) on the departure date (in Singapore). From the time of this dose until arrival in London, which is approximately 16 to 18 hours. Actrapid should be given at approximately 4 to 6 hourly intervals, coinciding with meals or snacks. Insulatard is not required while on board. Administer Actrapid and Insulatard, in combination again pre-dinner upon arrival in London, followed by the usual insulin regimen.

A return trip (London to Singapore) normally departs at 2215h (London). In this direction, the flight duration is 12 hours 40 minutes. Using a similar method of calculation, it will arrive in Singapore at I855h (the next day).

Administer Actrapid and Insulatard pre-dinner (with dinner) on the departure date (in London). From the time of this dose until arrival in Singapore, which is approximately 16 to I8 hours, Actrapid should be given at approximately 4 to 6 hourly intervals, coinciding with meals or snacks. Insulatard is not required while on board. Administer Actrapid and Insulatard, in combination again pre-dinner upon arrival in Singapore, followed by the usual insulin regimen.

Administering rapid acting insulin

Rapid-acting insulin is administered 0.1 to 0.2 units/kg every 4 to 6 hours, to coincide with regular meals or snacks. During long distance travel, long acting insulin administered before the flight will wear out (Insulatard wears out after 10 to 12 hours) and rapid acting insulin is necessary.

• Remember that Actrapid exerts blood glucose lowering effects not longer than 4 to 6 hours, with peak effects one hour after injection.

• For those on Novorapid, to duration of action is not longer than 3 to 4 hours with the peak effect within 15 to 30 minutes.

Singapore to New York return

To consolidate our concepts, let us consider a second example. The duration of a direct flight from Singapore to New York is 18 hours and there is a time difference of 13 hours. The flight departs from Singapore at noon (1200h) and arrives at 1700h in New York. For a child on twice daily (breakfast and dinner) insulin, a plan can be as follows:

Administer Actrapid and Insulatard pre-breakfast on the departure date (in Singapore). From the time of this dose until arrival in New York, which is approximately 22 to 24 hours. Actrapid should be given at approximately 4 to 6 hourly intervals, coinciding with meals or snacks. Insulatard is not required while on board. Administer Actrapid and Insulatard, in combination again pre-dinner upon arrival in New York, followed by the usual insulin regimen.

A return trip (New York to Singapore) normally departs at 2300h (New York). Using a similar method of calculation, this 18-hour flight will arrive in Singapore at about 0600h.

Administer Actrapid and Insulatard pre-dinner on the departure date (in New York). From the time of this dose until arrival in Singapore, which is approximately 22 to 24 hours, Actrapid should be given at approximately 4 to 6 hourly intervals, coinciding with meals or snacks. Insulatard is not required while on board. Administer Actrapid and Insulatard, in combination again pre-breakfast upon arrival in Singapore, followed by the usual insulin regimen.

An insulin plan is highly individualised

There are many factors that can influence which insulin plan is best for your child. For example, a child on Glargine (Lantus) instead of Insulatard will need a different plan. A different doctor may advise a different way of managing injections from the methods described above. Therefore, it is wise to formulate your child's individual plan and discuss contingencies with your own doctor before the trip to avoid unnecessary problems associated with diabetes control.

Be prepared to enjoy your holiday

To enjoy stress free vacations, plan ahead, be realistic and minimise changes. Remember that it pays to be prepared. The preparation checklist may be extensive and daunting, but necessary for you to have a good holiday, memorable for the right reasons. The insulin plan is important, but should not be the only item to prepare for. There are other equally important basic aspects of diabetes care that must be practised to ensure that the insulin plan works - blood sugar monitoring, meal portioning and spacing and appropriate response to blood sugar swings. Be prepared. and you will enjoy the holiday!

TRAVEL CHECKLIST FOR CHILDREN WITH DIABETES
 

Before leaving:

►    Optimise your blood glucose levels.

►    Choose an appropriate travel destination.

►    Revise hypoglycemia management.

►    Prepare a "hypo" kit.

►    Revise hyperglycaemia management.

►    Revise urine or blood ketone testing.

►    Ensure you have adequate supplies of insulin and syringes.

►    Ensure that the blood sugar meter works and you have enough blood sugar strips.

►    Obtain a letter for customs clearance.

►    Consult your doctor or specialist diabetes nurse to formulate an insulin plan.
 

During flight:

►Keep well hydrated.

►Check blood sugar levels 4 to 6 hourly.

►Administer rapid acting insulin 4 to 6 hourly with meals or snacks.
 

At destination:

►    Select suitable and avoid excessively strenuous activities.

►    Take good care of your personal hygiene.

►    Avoid consuming food that may result in a gastrointestinal illness.

►    Check blood sugar levels regularly.

►    Practise meal portioning and space out mealtimes where possible.

►    React to blood sugar swings - top up insulin when needed.

►    Have adequate rest each day.
 

Finally:

►    Be prepared to enjoy yourself.