chapter 9 Flashcards
what reduces the chance for successful defib ?
early defib
pausing CPR
duration of stopping CPR and
defib
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dry skin - wipe any moisture !
no barrier between the pad and skin
every min that passes between person collapsing and not receiving defib what happens to mortality rate ?
goes up by 7-10percent
bystander CPR doubles
what are all the three things a defib has ?
power source for direct current
a capacitator that can be pre-charged to a determined level
two electrodes
what is the definition of successful defib ?
the absence of VFIB AND VTACH after 5 seconds of defib - ALTHOUGH THTE ULTIMATE GOAL IS rosc
HOW MUCH OF THE defib current reaches the heart and why ?
only 4 percent
due to transthoracic impedance - electrical restance / electrode position / current diverted along non cardiac pathways
current flow is inversely proportional to transthoracic impendance
what are the speciality of some electrodes
biphasic electrodes can measure the transthoracic impedance and adjust the energy to compensate
what should be done with a patient with a hairy chest
only a problem is the pads do not attach
so if a razor blade is not immediately at hand - bi axillary electrode position is preferred
electrode position ?
no study to back up the best pad position - current during defib is so that the area of the heart which is fibrillating lied directly between the electrodes
place pad one below the right clavicle
the next mid axillary line on V6
should be clear of any breast tissue
the pads may be marked positive or negative but they can be placed in any of the position above
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anterograde posterior - one over the left precordium
the other below the left scapula
postero lateral - on one left v6
the other inferior to the RIGHT scapula
bi axially
what should we be aware of during defib ?
ICD- may be damaged with defib
place electrodes 10-15cm (>8cm) AWAY FROMT HE DEVICE
or use alternate position such as AP
ICD and pacemaker usually placed in left than right pectorial region
some s-ICD running parallel to sternum and end in left lateral position - for this AP position
total interruption to CPR and defb should be ?
less than 5 seconds
what are the shock energies ?
120-360J anything between these followed by fixed and escalating strategy - no evidence to say which is better
although escalating strategy - causes for lower incidence for refib
what are the safety alerts in defib pads ?
in oxygen rich environment and poorly applied defib pads = cause fire and significant burns to the patient
= self adhesive the best way to go
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take off oxygen mask
or nasal canula place them 1m away
leave ventilation bag connected to tracheal tube and or supraglottic airway
o alternatively discconect the ventilation bag from the tracheal tube and supraglottic airway and keep it 1m away from the patient’s chest during defib
what happens in terms when patient connected to ventilator
keep the tracheal tube connected to the ventilator tubing - unless chest compression prevent the ventilator to give adequate tidal volumes
int his case ventilator substituted for a ventilator bag - -which can be left connected to detached and removed from a distance of 1m
(ensure the disconnected ventilator tubing is placed also 1m away from the patient or better - switch ventilator to stand by
AED usefulness ?
extremely reliable in rhythm analysis
but not designed to deliver synchronised shock but will alert you to shock patient
AED can be used successfully before the arrival of hospital resus team for rapid rhythm assessment and shock delivery
considered in areas of the hospital with delayed defib due to time taken for resus team or no rhythm recognition skills
HOWEVER ALWAYS USE MANAL DEFIB IN PREFERENCE TO AED
SEQUENCE USE OF AED?
ensure unresponsiveness
call for help
start CPR
as soon as AED arrives switch it on and follow visual or voice direction
if shock advised - ensure nobody touches patient , and press shock
if no shock advised - resume CPR - continue with the visual and audio prompts
