Discuss the key differences in cardiac arrest management in a patient within 4 hours of cardiac surgery compared to management of cardiac arrest in a general ICU patient.
This is a lot like Question 3 from the first paper of 2020, except that time the examiners called them "modifications". "Outline the modifications to the standard adult ALS algorithm", thy asked. This time they wanted to "discuss the key differences". It would no doubt be highly instructive to learn, what possible key differences (or modifications?) could distinguish "outline" from "discuss" enough for the examiners to change the wording, but their minds are alien and inscrutable.
Anyway. The following "differences" can be identified:
- Differences in diagnostic thinking:
- Hypovolemia, tension pneumothorax and cardiac tamponade are among the most common causes of cardiac arrest following cardiac surgery.
- Differences in ALS algorithm:
- You do not use full dose adrenaline (rather, give smaller doses)
- You do three "stacked shocks"
- You try pacing (rate of 90, DDD) in asystole if pacing wires are available
- If they are already paced and in PEA, you turn off the pacing to "unmask" VF.
- These shocks and attempted pacing are all measures you take before starting CPR, which is a departure from the ACLS norms.
- If you can't control a shockable rhythm with three stacked shocks, you give amiodarone immediately rather than after three cycles.
- Amiodarone is the only drug in the protocol, which makes it easy to remember. Atropine is mentioned in the college answer but it is not a part of the 2017 consensus statement recommendations.
- The college suggests you grab the knife after one minute, but the official guidelines makers say "we recommend this within 5 minutes". In short, after five minutes of unsuccessful resuscitation the chest should be re-opened. External CPR is pointless in all of the common causes of arrest in this scenario. Therefore, CPR is something you do while waiting to re-open the chest.
- Differences in logistics
- Non-surgical staff are encouraged to re-open the chest in an emergency. However:
- Operating theatres, cardiac surgeon and cardiac anaesthetist need to be notified
- Blood bank need to be notified to be ready for a massive transfusion
- Additional steps which are not a part of the normal adult algorithm:
- Take the patient off the ventilator and manually ventilated them
- Drop the PEEP to zero, to optimise preload
- Stop the sedating infusions. With diminished cerebral perfusion, the chances of awareness are pretty minimal. In fact, stop all the infusion (to prevent drug errors).
- Switch the IABP to pressure trigger mode (that way it assists CPR)