delays to and interruptions of, plus duration of optimal cardiac compressions will significantly adversely impact coronary perfusion pressure
consider femoral artery US to monitor “pulse checks” looking for > 20cm/sec flow peaks as manual pulse checks interrupt compressions longer and have poor sensitivity
consider early art line to monitor BP
if refractory or recurrent VT / VF see electric storm for Mx options
introduction
mortality from in-hospital VF arrest:
“30%” if VF occurs and immediate defibrillation is perfomed
>95% if defibrillation delayed by > 12 minutes
mortality from Out-of-Hospital cardiac arrest (OHCA):
VF arrest - 66-96%
depending on bystander CPR, availability of early defibrillator use
likelihood of survival largely determined by return of spontaneous output by the time patient arrives in ED.
asystole - >99%
thus prevention is far better than the cure!
in-hospital Medical Emergency Team (MET) to attend and manage critically ill ward patients ASAP
timely assessment and Mx of patients presenting to ED with early senior doctor input to detect at risk patients.
community awareness of chest pain and need for ambulance transfers ASAP
Mx of choking victim
call for help
if effective cough:
implied mild airway obstruction thus encourage coughing and get help, remain with victim
ineffectual coughing:
implies severe airway obstruction
conscious:
call for help
give up to 5 back blows
if not effective, give up to 5 chest thrusts
if no relief but remains conscious, repeat above
unconscious:
call for help
commence CPR as below
Mx of primary respiratory arrest due to anaphylaxis or asthma
hypoxic brain injury is likely to commence within 4 minutes of PaO2 < 29mmHg or SaO2 < 40% and this will generally then progress to bradycardia then asystole
mouth to mouth ventilation, bag valve mask or LMA airway are very UNLIKELY to be of benefit as airway pressures are too high and it will only result in inflating stomach
IMMEDIATE intubation with rapid progression to surgical airway if 1st intubation attempt fails should be done if patient is in extremis, very agitated with hypoxia or unconscious
seizures are likely to be due to hypoxia - Rx the hypoxia not the seizures!
aggressive EARLY Rx with repeated epinephrine - 5 minutely IM or IV infusion if readily available if persistent wheeze, SOB or hypoxia in a patient with presumed anaphylaxis
aggressive EARLY Rx with inhaled salbutamol (and/or inhaled epinephrine if upper airway obstruction causing stridor such as in croup or anaphylaxis)
NIV may have a role whilst patient is awake
IV fluid bolus if also hypotense from anaphylaxis
immediate intubation by the most expert operator available WITHOUT waiting for sedatives to be used BUT with a muscle relaxant to help intubation if in extremis or unconscious
have an operator READY to perform surgical airway if intubation fails within 2 minutes or so of profound hypoxia - every SECOND COUNTS to avoid brain death!
ventilate at a low respiratory rate to allow sufficient time for air to be exhaled, consider squeezing chest to assist
consider pneumothoraces, especially if CPR has been used.
summary of Basic Life Support (BLS) for cardiac arrest
The Zombie CPR instructional video
7 components of BLS:
D: remove from danger
R: assess patient responsiveness
S: send for help
A: clear airway
head tilt-chin lift if non-trauma, or jaw thrust if trauma
remove vomitus using suction if possible
recognition and relief of foreign body airway obstruction
B: restore breathing although no longer the priority in adult out-of-hospital arrest
cardiac compressions alone (no ventilations) recommended for adult, out-of-hospital primary cardiac arrest (not respiratory) if witnessed, and with shockable rhythm or short period (<4 minutes) of untreated arrest
cardiac compressions alone also recommended if bystander not trained in CPR, or not confident in their ability
breaths (in hospital or those trained in CPR):
bag and mask if available (and oxygen at 15L/min to deliver 85% oxygen if available)
2 effective breaths every 30 compressions with a 1 second inspiratory time (except neonates, give 40-60 breaths/min)
if unprotected airway, pause compressions during breaths
if protected airway (eg. ETT in situ), don't pause compressions, and rate should 1 breath every 15 compressions (2 breaths in children every 15 compressions)
bag size:
> 18kg or > 5yrs old, use a 1600ml adult bag
infant, use a 500ml bag
neonate, use a 240ml bag or neonatal circuit
C: establish circulation:
checking for pulses is unreliable, instead start compressions if no signs of life, for instance:
unresponsive or unconscious
not breathing or the occasional gasping breath
not moving
cardiac compressions over mid-sternum to a depth of 1/3rd chest (eg. 4-5cm in an adult) at a rate of 100 per minute for all ages, stopping to allow 2 breaths every 30 compressions if unprotected airway
early cardiac compressions may:
prevent VF deteriorating into asystole
increase the chance of successful defibrillation in VF
add to the preservation of brain and cardiac function
D: availability of semi-automatic external defibrillators:
defibrillation as soon as possible provides the best chance of survival in victims with VF or pulseless VT
if cardiac arrest occurs in the obviously pregnant woman, place in a left lateral tilt by placing a pillow or wedge under the right buttock - this will reduce compression of IVC and aid venous return.
summary of Advanced Life Support (ALS) for cardiac arrest
consider and correct:
hypoxia (eg. see above under Mx of respiratory arrest)
hypovolaemia
hyperkalaemia, hypokalaemia and other metabolic disorders
tension pneumothorax
tamponade
toxins
thrombosis (PE/AMI)
continues the principles of BLS but then splits depending on:
intubation should not interrupt chest compressions for more than 20 seconds
avoid hyperventilation as risk of complications from increased intrathoracic pressure, and decreased coronary and cerebral perfusion.
ventilation rate once intubated should usually be 8-10 breaths/minute, without pausing for chest compressions (rate 15:1)
confirmation of correct endotracheal tube placement - eg. end-tidal CO2
markers of brain damage
serum neurofilament light levels at 24hrs are a highly accurate predictor of long-term outcome after cardiac arrest in terms of predicting the primary 6 month outcome of either good (modified Rankin Scale 0–3) or poor (modified Rankin Scale 4–6) functional outcome2))