The Traveller with Chronic Medical Conditions

Karen McClean, MD FRCPC

University of Saskatchewan

The “unwell” traveller

• Cardiac disease• Respiratory disease• Diabetes• Renal Failure• Neurologic disease• Immune deficiency• Malignancy• Chronic connective tissue diseases

The “unwell” traveller: general advice

• Medic alert bracelet• Medications

– dual supply (carry-on and checked luggage)– list of medications

• generic names• full dosing information • indications

• Physician contact information• Copy of relevant lab data

– 12 lead ECG: copy and report– arterial blood gases– recent lab results (INR, creatinine etc.)

The “Unwell” Traveller: General Advice

• Delay travel until underlying disease is under optimal control

• Review contraindications to air travel• Review altitude risks if appropriate• Maximize all appropriate prophylactic measures• Plan ahead

– special meals (diabetic, low salt, low cholesterol)– oxygen

• Contingency plans– physicians - IAMAT– insurance and evacuation

Medical contraindications for air travel

• Any patient sick enough to have a low probability of surviving the flight

• Any serious and acute contagious disease

• Cardiovascular disease

• Respiratory disease

• Neurologic disease

• Post-operative

Cardiovascular contraindications

• Unstable angina or chest pain at rest• Recent MI

– Uncomplicated = within 2 weeks– Complicated = within 6 weeks

• CABG within past 2 weeks• Decompensated heart failure• Uncontrolled arrhythmia • Uncontrolled hypertension (sys. BP > 200)

Respiratory contraindications

• Baseline PaO2 < 70 mmHg at sea level without supplemental O2

• Pneumothorax within the past 3 weeks

• Large pleural effusion

• Exacerbation of or severe COPD

• Breathlessness at rest

Neurologic contraindications

• Stroke within 2 weeks• Uncontrolled seizures

Post-operative / trauma contraindications

• Recent surgery or trauma where trapped air or gas may be present– Abdominal trauma– Gastro-intestinal surgery– Craniofacial surgery– Ocular surgery

• Diving related decompression illness and gas embolism (without recompression chamber)

High Altitude Flight and Medical Disease

High Altitude Flight

• Commercial jet engines operate best at altitudes >30,000 feet– Cabin pressures: 5,000 - 8,000 ft (1,500-2,500

meters) above sea level

• 35,000 ft: cabin pressure = 5,500 ft above sea level– PO2 decreases from 159 mmHg to 128 mmHg– PAO2 decreases from 107 mmHg to 74 mmHg– PaO2 decreases from 98 mmHg to 65 mmHg– Saturation for normal individuals = 94%

High Altitude Flight

• In practice, cabin “altitudes” usually range from 6,000-9,000 feet, resulting in even greater effects on oxygen levels

• As long as the PaO2 > 60 mmHg: oxygen-hemoglobin dissociation curve is flat and oxygen delivery is unaffected.

• Once the PaO2 falls below > 60 mmHg, there is a rapid decrease in oxygen delivery.

Hypoxemia & High Altitude Flight

Hypoxemia & High Altitude Flight

• Underlying respiratory impairment may lead to reduced PaO2 at normal flight altitudes

• Hypoxemia tachycardia increased oxygen demand ischemia

High Altitude Flight

• Trouble….– Impaired hemoglobin saturation

• Ventilation problems• Diffusion capacity problems

– Impaired oxygen delivery• Anemia • Impaired tissue perfusion

– Coronary artery disease– Intestinal ischemia– Peripheral vascular disease

Cardiac Disease

Travel issues for cardiac patients

• Cardiac events:– Most frequent cause of death in adult travellers– Most common cause of inflight death (>50%)– Second most common reason for medical

evacuation

Cardiac Disease and Travel

• Common conditions– Coronary artery disease– Congestive heart failure– Valve replacement– Atrial fibrillation

• Key concerns– Altitude effects on O2 supply – demand– Decompensation of CHF or CAD– Managing anticoagulation– Drug interactions– Pacemaker and ICD function / interference

Supply and demand

• Increased demand– Physical exertion in transit or at destination tachycardia– Psychological stress of travel tachycardia– Acute high altitude exposure hypoxia induced stimulation

of sympathetic nervous system, tachycardia, hypertension– Tachycardia increases oxygen demand

• Decreased supply– Altitude– Anemia– Impaired perfusion – CAD

• Risks– Angina, myocardial infarction, arrhythmias

Assessment: History• Review history of coronary artery disease

– MIs: when, severity, complications?– Revascularization?– Rehabilitation?

• Current angina triggers?• Ability to climb 2 flights of stairs without

difficulty?• Medications?• Frequency of rescue nitrate use?• Arrhythmias?• Symptoms of heart failure?

– Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, poor exercise tolerance, edema

Interventions

• Refer for formal assessment if concerns– Difficulty with ADLs– Frequent use of rescue medication– Symptoms of CHF– High risk travel: altitude, activities, remote

• Stair climb test

• Stress test – no evidence for use– Assess response to tachycardia

Recommendations to traveller

• Underlying disease should be optimally controlled– Review by usual physician to ensure all

appropriate treatments are being used– Changing medications immediately before travel

may jeopardize insurance coverage• Recent baseline ECG: take both paper copy

and interpretation• Accurate medication list• Physician contact information• Documentation of pacemaker, IAD

Anticoagulation

• Valve replacement– Bioprosthetic valves: anticoagulation

usually discontinued– Mechanical valves: permanent need for

anticoagulation

• Atrial fibrillation

The Traveller on Warfarin

• INR will be affected by:– Diet - changing vitamin K intake

• Provide list of moderate to high vitamin K content foods– Exercise and activity level– Illness– Drug interactions– Ascent to high altitude

• Effects usually seen in 3-5 days• Enhanced monitoring is recommended

given potential exposures to INR altering influences

Warfarin monitoring• Use of INR removes the uncertainties of reporting

by seconds • Self monitoring eliminates need for use of local

facilities but is not common in Canada– Self monitoring machines are bulky compared to

glucometers– Power source issues need to be considered– Traveller should be stabilized on self monitoring and

treatment well before travel• Health providers in other countries may not be

familiar with warfarin (other agents may be standard care), may have difficulty recommending appropriate dose adjustments.

• http://www.acforum.org/locations.html provides list of anticoagulation clinics in other countries – but many countries not represented

Pacemakers

• Bipolar (modern) pacemakers are not affected by electronic interference from aviation industry products

• Older unipolar pacemakers may malfunction from electronic interference from security devices or airplane devices

• IADs: hand held security devices may trigger IAD

Malaria prophylaxis

• Warfarin interactions: increased INR and bleeding risk– Doxycycline – Malarone– Proquanil

• Digoxin interactions: chloroquine

• Prolonged QT interval: chloroquine, mefloquine

How do you decide when you can / should not recommend CLQ

or MFQ?• “Use caution when prescribing drugs that prolong the

QT interval in the presence of one or more risk factors, especially if the individual is already on one or more medications that can prolong the QT interval.”

• ‘Co-administration of Mefloquine with cardioactive drugs might contribute to the prolongation of QTc intervals, although in the light of information currently available, co-administration of such drugs is not contraindicated but should be monitored.’– Travel Medicine, Schlagenhauf, Beallor, Kain

When is it OK to use CLQ / MFQ?

• Should chloroquine or mefloquine be prescribed to travellers already using QT prolonging drugs?– Consider options– Consider risk factors (age, female, bradycardia, electrolyte

disturbance, structural heart disease [MI, CHF, LVH])– The presence of multiple risk factors warrants caution– Avoid in congenital LQTS

• If in doubt…– Screen with ECG

• AV block (any degree)• Interventricular conduction delay• Bundle branch block• Prolonged QT interval

– Consult with cardiologist

Summary: Cardiac disease

• Review travel plans in detail– destination: heat stress, altitude– access to care– activities– living arrangements (?elevators, air conditioners)

• Review fitness for travel– contraindications to air travel– review ADLs: can cardiovascular fitness be improved before

travel?– 12 lead ECG: conduction abnormalities / LVH– stress testing - does tachycardia precipitate ischemia?

Respiratory disease

Respiratory disease

• Issues for travellers with respiratory disease– Altitude– Air quality – Allergens– Pathogens

High Altitude flight and respiratory disease

• Travellers with hypoxic lung disease are at risk of symptomatic deteriorations in oxygen delivery at altitude– Emphysema– Chronic bronchitis– Interstitial lung disease– Asthma– Cystic Fibrosis– Recurrent pulmonary emboli– Chronic hypoventilation: Obesity hypoventilation

syndrome, Obstructive sleep apnea, neuromuscular disease

Assessing need for oxygen

• Risk Assessment– minimal risk

• destination altitude < home altitude• able to climb two flights / walk indefinitely on

level

– increased risk• Baseline PaO2 < 70 mmHg • FVC < 50% of expected • SaO2 < 92% (or 92-95% with risk factors)• 50 meter walk test: inability to complete,

angina, distress• Various other predication equations or graphs

Oxygen saturation

• Simple, rapid, office based• Oxygen not required

– SaO2 > 95% no oxygen required– SaO2 92-95% with no risk factors

• Further investigation required– SaO2 92-95% with risk factors

• Oxygen required– SaO2 < 92%

• Risk factors: hypercapnia, FEV1 < 50%, lung cancer, restrictive lung disease (chest wall, muscle or parenchymal disease), cerebrovascular or cardiac disease, within 6 weeks of exacerbation of chronic lung disease or cardiac disease

Predicting hypoxia

• Hypoxia Inhalation testing (HIT)– Inhalation of hypoxic gas mixture – equivalent to 8,000 ft

altitude (15.1% O2)– Assess: clinical status, ABGs (PaO2 < 50 mmHg, SaO2

<85%), ECG changes of ischemia or strain– Imprecise correlation of PaO2 with actual PaO2 under

hypobaric conditions - not recommended for routine use

• When should HIT be done?– Co-existing conditions adversely by hypoxia– Symptoms during previous air travel– Recovering from acute exacerbation of lung disease– Hypercarbia or hypoventilation with oxygen administration

Predicting hypoxia

• Regression Formulae– Compare a patient with a group of patients with similar

characteristics who have previously been studied under hypoxic conditions

– More physiologic basis than HIT– Does not permit assessment of individual susceptibility to

symptoms or ECG changes during hypoxia– Most formula’s have been worked out in COPD patients

• Predicted in-flight PaO2

– [0.453 x Ground PaO2] + [0.386 x FEV1%] + 2.44– [0.410 x Ground PaO2] + 17.652– Numerous others!

What’s the evidence?

• 50 meter walk test: not validated in prospective studies

• HIT test: not validated in prospective studies• Kids with CF: spirometry better predictor

than HIT– HIT: sensitivity = 20%, specificity = 99%– FEV1< 50%:sensitivity = 70%, specificity = 96%

If there is a lack of good evidence, what do we do?

• Screening tests: – 50 meter walk test– Oxygen saturation

• Failed screening tests or high risk– Spirometry: FEV1 < 50% predicted

– ABGs: PaO2 < 70 mmHg

• Traveller with CO2 retention – consider HIT

• Collaboration between respirologist and travel medicine specialist

Who should be assessed for supplemental Oxygen?

• Cardiac– Ischemic heart disease – Dilated cardiomyopathy / amiodarone lung– Eisenmenger’s syndrome– Congestive heart failure

• Pulmonary– Severe COPD or Asthma– Pulmonary fibrosis– Restrictive lung disease due to chest wall or respiratory

muscle disease– Pulmonary hypertension

• Primary• Secondary (recurrent pulmonary emboli)

– Cystic fibrosis• Already on home Oxygen

Supplemental Oxygen

• Requires physician's prescription: – Duration + 60 minutes for delays– Intermittent or continuous use– Flow rate at 8,000 feet

• Usually 2 litres / minute• Add 1-3 l/minute for patients already on O2

• Arrangements must be made with each individual carrier and for each flight segment– Costs and required notice differ by carrier– Check in procedures may change (↑ time required)– Personal oxygen delivery devices CANNOT be used

(portable tanks etc.)• Oxygen for use during lay-overs and at destination

– Must be arranged through commercial oxygen supply companies

Other issues

• Air quality and allergens– Large urban centers – high traffic density – Industrial air pollutants– Cigarette smoking– Low humidity– Asthmatics and others with reactive airways may

experience exacerbations from exposure to air pollutants and allergens.

• Ensure optimal control before departure• Monitor peak flows for early warning signs• Plan for increased use of rescue meds• Standby steroids?

Other issues

• Pathogens and the risk of pulmonary infection– Chronic respiratory disease increases the risk of

infection– Use of steroids in treatment for respiratory

disease may also increase infection risk– Increased risk of exposure: in close quarters:

buses, planes etc– Exposure to new pathogens: lack of prior

exposure increases risk of infection– Risk of triggering an exacerbation of underlying

disease

Questions?

Diabetes and Travel

Diabetes and travel: issues

• Diabetic control affected by:– Changing time zones– Less control over meals: timing, food selection,

availability– Less control over activity levels– Acute travel related illness– Altitude effects on glucometer and insulin pumps

• Older glucometers affected by altitude, reportedly less problems with new meters.

• Have alternatives!

– Increased absorption of insulin in hot climates (increased blood flow to skin and SC tissues)

Diabetes and travel: issues

• Air travel security: insulin pumps, lancets, insulin– Insulin must be in original packing with preprinted

pharmaceutical label on box– Glucagon must be in preprinted labelled packaging– Lancets must be in original packaging and must match the

glucometer, must be capped– Physician letter outlining supplies to be carried

• Immigration: syringes and needles, drugs– Physician documentation required

• Access to supplies at destination– Insulin storage for long trips (< 1 month ok at RT)– Some types of insulin syringes are not widely available

(U100 syringes esp.)

Diabetes and travel: issues

• Neuropathy: risk of foot injury– unaccustomed walking, inappropriate footwear (sandals,

hiking boots, new footwear)• reinforce need for careful examination of feet (daily) and

proper foot care• advise against new footwear for travel – should be broken in

well in advance if needed• alternate footwear • frequent changes of socks in hot climates• standby antibiotic therapy in event of infection

• Retinopathy: transient worsening of vision due to hypoxic retinal ischemia during high altitude flight

• Nephropathy: adjust doses of prophylactic or standby medications– increased risk of renal failure if dehydration occurs

Diabetes management

• Oral hypoglycemics– No dose adjustment required for travel

• Insulin: regular / long acting insulin regimens– No dose adjustment if < 5 time zone change– Westward travel: longer day requires more insulin– Eastward travel: shortens day, requires less insulin

• Insulin: basal / immediate acting regimens– Easier to manage changing time zones – May be injected immediately prior to a meal

(Regular insulin needs to be taken 30-45 minutes prior to a meal…delays may result in hypoglycemia)

Insulin dose adjustment

• Rule of thirds:– Travel west: insulin by 1/3

• Day of departure: take usual morning insulin• pm insulin 10-12 hours later• Blood sugar 18 hours after morning insulin: if > 13 mmol/l,

take 1/3 morning dose + snack• Resume usual doses morning of arrival

– Travel east: insulin by 1/3• Day of departure: take usual morning insulin• Evening dose 10-12 hours after am dose• Day of arrival: take 2/3 usual am insulin, BS in 10 hours

• 2-4% adjustment in insulin dose per time zone

Standby antibiotics

• Treat travellers diarrhea

• Treat skin and soft tissue infections– Keflex, erythromycin

• Diabetic foot infections – Usually polymicrobial– Clavulin, Cipro + flagyl

• Treat vaginal candidiasis– Fluconazole

Drug interactions: hypoglycemic medications

• Very limited evidence…..– Doxycycline may occasionally potentiate the

effects of insulin and sulfonylureas– Chloroquine may improve glucose tolerance in

type 2 diabetics – No clear evidence for interactions with

mefloquine

• No indication to avoid any particular antimalarial agent – but data is limited especially for newer drugs

• Increased monitoring of blood sugar

Diabetes and travel• Take all required supplies in original packages• Take extra insulin to allow for problems• Contingency plans

– Insulin adjustment protocol– Take an additional supply of regular insulin– Alternate methods of blood sugar tesing– Alternate methods of insulin delivery if pump used – Dealing with hypoglycemia:

• snacks and sugar supplements• glucagon

• Be prepared to deal with– Travellers’ diarrhea– Skin and soft tissue infections– Yeast infections

What’s the concern?

• Prolonged QT intervals increase the risk of polymorphic ventricular tachycardia (Torsade de Pointes – TdP) and sudden death

• Long QT can be congenital or acquired• Greatest risk = congenital Long QT syndrome (LQTS)• Other risk factors for adverse events:

– Female gender (2X increase in risk)– Increased age– Structural heart disease (LVH, CHF, MI)– Bradycardia / β blockers (QT lengthens as HR slows)– QT prolonging drugs, especially concurrent use of multiple

drugs that prolong QT– Hypokalemia, hypomagnesemia (diuretics!), hypocalcemia– Hypothyroidism

CLQ, MFQ and QT• Data is sparse!• Different ‘experts’ = different recommendations!• Chloroquine

– listed as a drug to avoid in at risk individuals– isolated case reports – usually therapeutic doses– risk is likely significant with high doses, much less or

minimal with prophylactic doses– studies flawed by low numbers, use of healthy subjects (not

at risk individuals)• Mefloquine

– does not appear on many of the ‘QT drugs to avoid’ lists– isolated case reports (esp. co-administration with

Halofantrine)– prolongation of QT – mild in some studies, none in others– can cause sinus bradycardia– ‘interaction studies are needed’

QT prolonging drugs

• Many different drugs and classes represented• Useful categorization….

1. Drugs with risk of TdP• Chloroquine, quinine• Macrolides (clarithro, erythromycin)

2. Drugs with possible risk of TdP• Quinolones, azithromycin, effexor

3. Drugs to be avoided in Congenital LQTS• Includes list 1 and 2 drugs plus additional drugs

4. Drugs unlikely to cause TdP if used in absence of other risk factors• Ciprofloxacin, azoles, TMP-SMX, celexa, prozac

• www.qtdrugs.org/