Acute Care - Arrest, Brady and Tachy Flashcards
where are pacemaker cells found?
SA node
what happens in pacemaker cells?
decreased K efflux + increased Na influx
then Ca influx causes the spike
once at the top, K efflux increases and Ca influx decreases
what happens in ventricular muscle cells?
increased Na and Ca influx
plateau occurs, Na channels close
after this, Ca influx increases and K efflux occurs
Ca channels close and K efflux continues
what can cause bradycardia?
hyperkalaemia
BBB
heart block
physiological
Tx for bradycardia?
observe if no adverse features
500mcg IV atropine (repeat up to 6 times)
can give adrenaline IV
transcutaneous pacing
how does atropine work?
inhibits muscarinic actions (parasympathetic)
what are causes of tachy - broad vs narrow?
narrow =
atrial flutter
AF
re entrant SVT
broad =
AF + BBB
VT
SVT +BBB
what is the Tx for narrow QRS, regular rhythm tachycardia?
vagal manouvres
adenosine 6mg IV
how does adenosine work?
activates K channels to hyperpolarise and cause delay between AV node
what is the Tx for narrow QRS, irregular rhythm tachycardia?
probably AF
Bblocker/CCb
or
digoxin/amiodarone if HF
what is the Tx for broad QRS, regular rhythm tachycardia?
probably VT
amiodarone 300mg IV
what is the Tx for broad QRS, irregular rhythm tachycardia?
AF with BBB - treat alike narrow complex
polymorphic VT - magnesium 2mg
4H’s of cardiac arrest?
Hypovolaemia
Hypothermia
Hypo/hyperkalaemia
Hypoxia
4T’s of cardiac arrest?
Tension pneumothorax
Thrombus
Tamponade
Toxins
what is the specifications of good chest compressions?
30:2
100-120 a min
5-6cm depth
what are the shockable rhythms?
VF
pulseless VT
when and what drugs are given during CPR?
adrenaline 1mg IV every 3-5 mins (alternate shocks)
30mg amiodarone after 3 shocks
how long should CPR be done for between shocks?
2 mins
how is paediatric CPR done?
head tilt after 1yr
5 rescue breaths: 15 compressions
when is adrenaline given if it is confirmed to be a non shockable rhythm?
as soon as
if a non shockable rhythm, what is the CPR pathway?
recheck every 2 mins
regive adrenaline every 3-5mins
