Transcript Pre Travel Consultation - Winnipeg Health Region

The Traveller with Chronic
Medical Conditions
Karen McClean, MD FRCPC
University of Saskatchewan
The “unwell” traveller
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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
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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
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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: oxygenhemoglobin 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
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Coronary artery disease
Congestive heart failure
Valve replacement
Atrial fibrillation
• Key concerns
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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
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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
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AV block (any degree)
Interventricular conduction delay
Bundle branch block
Prolonged QT interval
– Consult with cardiologist
Summary: Cardiac disease
• Review travel plans in detail
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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
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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
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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?
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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
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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
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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.
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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
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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:
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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
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Many different drugs and classes represented
Useful categorization….
1. Drugs with risk of TdP
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Chloroquine, quinine
Macrolides (clarithro, erythromycin)
2. Drugs with possible risk of TdP
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Quinolones, azithromycin, effexor
3. Drugs to be avoided in Congenital LQTS
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Includes list 1 and 2 drugs plus additional drugs
4. Drugs unlikely to cause TdP if used in absence of other risk
factors
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Ciprofloxacin, azoles, TMP-SMX, celexa, prozac
www.qtdrugs.org/