Questions Flashcards
Why do we do CPR?
The function of the heart is to pump blood to the lungs and body (including heart and brain) using a double pump system and therefore provide oxygen and glucose and remove waste products that can become toxic to the body.
We do 30 compressions to 2 breaths for adults, compressions should be at a rate of 100-120 bpm – faster than heat beat due to them being less effective.
The aim of CPR is to delay tissue death by keeping the oxygenated blood moving into/out of the lungs and body, buys time for other interventions to restart life.
We minimise interruptions as time without CPR means blood/oxygen is not flowing, additionally it takes several compressions for the pressure of blood flow to return and therefore the first few are less effective.
You must let the chest return to its usual position after each compression in order to allow blood to re-enter the heart making future compressions more effective.
Why do we give 5 rescue breaths in PALS?
Most likely cause is hypoxia or pt is respiratory arrest in paeds so 5 rescue breaths aim to reverse most likely reversible cause. Important to check airway and remove blockage – common in children.
2-person technique to ensure adequate seal and ensure the 5 breaths provide good oxygenation levels with high flow oxygen and good rise and fall.
Oxygenating with high flow increases 02 in blood during cpr. Provide enough oxygen to preserve/prevent as much cell depth/hypoxia which trys to prevent brain damage or death within the heart as that can happen within 3 mins of inadequate oxygenation.
Gives rescuer extra time to observe for signs of life during the breaths as sometimes these alone are enough to restart life.
Can push/encourage blockage/fluid out of airway/lungs, rarely do children have cardiac issues so hypoxia is most likely primary cause.
How would you manage a pregnant cardiac arrest?
Displace uterus to the left or left tilt, if possible, to relieve pressure on aorta and inferior vena cava as this pressure can decrease cardiac output while pt is flat.
If no ROSC within 5 mins undertake time critical transfer to nearest maternity ED, continuing ALS as normal, may want to hysterotomy early in hospital. Perimortem c section will be considered within 5 mins of no cardiac effort, can be done by hospital or critical care – phone advice line.
Call maternity/labour line for advice/support, pre alert maternity that you are coming in.
Identify reversible cause early eg hypovolemia with PPH and try to reverse.
Debrief with multi-disciplinary staff involvement to ensure minimised psychological harm.
Why do we defibrillate?
In a shockable rhythm the hear is beating in a fast ventricular rhythm which doesn’t allow the heart to fill or contract properly.
Pads are placed right side of the chest and lower side of left chest, or for children 1 on back 1 on front. Consider new pad placement after 5 shocks eg anterior/posterior, suggested to replace pads after multiple shocks.
Defib aims to depolarise the heart muscle allowing all the muscles to repolarise at the same time hopefully back into a sinus rhythm. Chest compressions increase the chance of shocks working so important not to delay compressions. High amount of energy through the heart to stop it and allow body to restart hopefully correctly.
Public access ones have become available to public which analyse the rhythm and decide whether to shock or not, as we are not always on scene immediately but every minute counts so these can help provide quick shocks meaning ROSC is more likely.
What is the pathophysiology of shockable rhythms?
Normal electrical activity becomes interrupted, impulse originates in the ventricles which cause them to pump ineffectively. These rhythms can be corrected with good CPR, drugs and shocks to restart the heart.
VF – Myocardium fires off randomly, heart ‘fibrillates’ and fills with pooling blood. Fast disorganised rhythm originating from multiple places and is not synchronised with the atria. The lower chambers quiver/fibrillate and therefore heart does not pump blood to the body.
VT – Rapid electrical activity, Myocardium fires off but still with some coordination, reduction of cardiac output. Fast rhythm causing ventricles to contract rapidly (over 100bpm) giving them no time to refill. Must check if theres a pulse as to be shockable there has to be no pulse.
VT can degenerate into VF
What is the pathophysiology of non-shockable rhythms?
Asystole – no electrical activity, ‘flatline.’ no perceptible cardiac electrical activity. No heart contractions.
PEA – Electrical activity and activation of the myocardium with no contraction. Rhythm is compatible with life but no pulse, volume issue. Mechanical activity at fault not the electrical organisation.
No potentials for the shock to work with in asystole, in PEA the electrical activity is compatible with life so shocking could send the heart out of rhythm.
