Inter-hospital Aviation Transport
of Neonates
By: B Lessing
Reg. Sister / PHPLS / ACLS /
FMA / ALS Paramedic
OBJECTIVES OF AERO-MEDICAL TRANSFERS
• To provide the basic understanding around
the principles of aviation medicine;
• To appreciate the impact of the stressors
of flight on both the practitioner, the patient
and the parent; and
• To introduce the principles of in-flight care.
INTRODUCTION
• Aero-medical evacuation is safe for
transporting almost any patient
• BUT ... The following conditions must be met:
• WELL-PREPARED, well-trained medical
escort / team
• Medical EQUIPMENT that is qualified as
“safe for use”
• A therapeutic dose of pessimism!
THE STRESSORS OF FLIGHT
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•
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Hypoxia
Barometric pressure and gas expansion
Gravitational forces
Thermal changes
Noise and vibration
HYPOXIA
Hypoxia in aviation is a syndrome that is
usually acute and results from inadequate
oxygenation of the tissues secondary to a
decreased partial pressure of oxygen in
the inspired air
– Four types of hypoxia:
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•
•
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Hypoxic hypoxia
Anaemic hypoxia
Histotoxic hypoxia
Stagnant hypoxia
BAROMETRIC PRESSURE
GAS LAWS:
• Boyle’s Law (Pressure varies inversely with volume): This law
can affect things like: chest drains, catheters, ETT, pneumothorax,
gastric distension, ileus hernia, necrotizing enterocolitis (NEC – can
rupture into the peritoneal cavity). These patients should be flown at
lowest cabin pressures possible
• Charles’ Law (Pressure constant; temperature varies directly
with volume): Cabin pressures and the patients temperature can
may influence the volume of trapped gases. Also and increase or
decrease in temperature can move the oxygen disassociation curve
to the left or right thereby affecting oxygenation of cells. Therefore it
is vital that the incubator is fully functional and maintains the correct
homeostatic environment.
• Gay Lussac’s Law (Volume constant. Temperature varies
directly with pressure)
• Dalton’s Law: (Total barometric pressure is equal to the sum of
the partial pressure of each gas)
GRAVITATIONAL FORCES
PROBLEMS UNDER G-FORCE
• Cardiovascular Effects: Black out / LOC /
Convulsions / Amnesia / Confusion / Cardiac
dysrhythmias / Tachycardia / Bradycardia / Heart block
/ Any cardiac defects e.g. PDA, ASD and VSD
• Respiratory Effects: Altered VQ ratios e.g. HMD,
Meconium aspiration / Airway closure and Atelactasis
• Renal System Effects: Decreased renal blood flow /
Oligouria / Increased plasma levels
• Musculoskeletal Effects: Back, neck and limb
problems / Inter-vertebral disk rupture
THERMAL CHANGES
• Heat and cold: (differences in
temperature from one area to another)
• Altitude: ( higher altitude – colder)
• Immuno-compromised: patient exposed
to weather and climate conditions and
variations
HEAT LOSS PREVENTION IN
NEONATES
• Maintaining a neutral thermal environment is one of the key
physiological challenges a newborn infant faces after delivery.
• Thermal regulation is distinctly different in newborns than in
adults. In adults, the responses to a cold body temperature include
peripheral vascular constriction, inhibition of sweating, voluntary
muscle movements, involuntary muscle movements (shivering) and
nonshivering thermogenisis. Neonates do not exhibit many of these
responsis
• Nonshivering thermogenisis is the main mechanism of heat
production in neonates. Nonshivering thermogenisis occurs due
to an increase in sympathetic activity leading to an increase in
norepinephrine and thyroid-stimulating hormone.
Thyroidstimulating hormone leads to an increase in T3 and T4. These
mediators cause increased fat oxidation and heat production.
This represents a large caloric demand. A newborn infant left
unattended in a room at room temperature experiences energy
losses of approximately 140kcal per min.
HYPOTHERMIA
• Infants exposed to cold temperatures are at risk
for increased mortality
• Normal temperature ranges for the neonate is 36.5
to 37.7˚C
• Cold stress may occur when temperature drops to
36˚C
• Temperatures below 36˚C are considered
hypothermic
• Moderate hypothermia is considered to be
between 32 and 36˚C.
• Severe hypothermia is considered when the
infant’s temperature is less than 32˚C.
PATHOPHYSIOLOGY OF HYPOTHERMIA
• Hypothermia results in a variety of physiologic stresses.
• The infant has increased oxygen consumption, metabolic
acidosis, hypoglycaemia, decreased cardiac output and
increased peripheral vascular resistance
• Over two-thirds of low birth weight infants are admitted to
neonatal intensive care units with temperatures that would
be considered hypothermic
• Therefore the main objective of aero-medical transfer of
neonates lies in the correct management of temperature.
NOISE AND VIBRATION
• Constant noise – Difficult to communicate:
Engines / turbulence / equipment / ear
muffs
• Headaches
• Neonates are very sensitive to noise and
therefore causes aggravation
INFORMATION
• The attending physician – determine
destination, urgency, and mode of transport
• Discuss additional steps to further stabilize
the patient
• An appropriate SAMPLE history
• The results of diagnostic tests
• Any special equipment or staff requirements
• Any problems anticipated
CREW
• The crew on the flight are the crew who will treat the patient –
therefore know which crew are most required!
• The crew should be current with their aviation orientation
• The crew should be familiar with the layout of the plane and
where the equipment is stored
• The crew should know and understand and be able to explain
to patients and escorts the emergency procedures in the
event of an emergency
• A Golden Rule: TRUST AND SHARE YOUR GUT FEELING
TO THE FLIGHT AND MEDICAL CREW - ANY bad feelings
MUST NOT BE IGNORED – no matter how trivial they may
seem!!!
EQUIPMENT
• Critical aspect of any transfer – what you
don’t have cannot be used
• Prepare an inventory of all necessary
supplies and equipment
• Check and test all equipment prior to
departure
• Have a “PLAN B”
• A N T I C I P A T I O N!
EQUIPMENT
•
Defibrillators
– Artefacts from vibration may occur
– Ensure backup power supply / batteries
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NIBP
– Gas expansion in cuffs may give inaccurate readings
•
Pulse Oximeters
– Vibration and noise may affect signal
– Poor perfusion / temperature may affect readings
•
Dopplers
– Useful to assess pulses or foetal heart tones
•
Incubator
– Should be set at correct temperature
– should have more than required battery supply (for the whole mission and not just the
flight
– Spare warm blankets in case of incubator failure
PRE-FLIGHT STABILIZATION
• This is one of the most critical aspects of
any transfer!
• Don’t be forced into a “scoop and run”
scenario (obviously there may be some
exceptions)
• Aero-medical “Feng Shui” – it is important
to plan the packaging of patients and
equipment according to your anticipation
of what “can go wrong.” Access is vital!!!
PATIENTS AND ESCORTS
• Unless the mother is ill – she should accompany
the neonate
• Ensure ID Bands are checked by the mother and
receiving crew and hospital staff
• A toy for the child helps for comforting them
• Patients, equipment and all supplies should be
secured safely before take-off and during the flight
• Before take-off, ensure that: the escorts, patients
and crew are familiar with the emergency
procedures and know where the emergency exits
are.
Questions
End