Cardiac Arrest:
No two words are more synonymous with EMS than “Cardiac Arrest”. When people think of paramedics, the image that usually comes to mind is of an unresponsive person, with CPR in progress, IVs being placed, and someone squeezing a BVM. Admittedly, this was my initial impression of the field, and probably had a lot to do with me entering EMS. Running a code is probably one of the most intimidating tasks faced by paramedics, regardless of experience level. Each one is the same, yet different in several aspects. Sometimes we have difficult extrications, small quarters, dangerous scenes, difficult bystanders, or we simply run out of options and have to terminate resuscitation. This review is not intended to be a one-size-fits-all approach to cardiac arrest management. It is simply a review of the process, and framework that we follow on every arrest, and is intended to serve as a refresher for those looking to enhance their practice. I also want to review termination of resuscitation, and prognostic indicators. Take what you find useful. I will point out that as a primary care paramedic, I do not use ACLS during arrests, however I do work with ALS providers and am familiar with the protocols here. I will give a brief overview of the ACLS algorithm in addition to BLS arrest management.
Our approach to a patient in cardiac arrest is not so different than for any “unresponsive patient”, in that we begin our assessment upon arriving on scene. We want to first ensure that the scene is safe, lest we fall victim to potential threats. We want to be observant for possible clues as to a possible external cause for the patient’s death, such as drugs, CO poisoning, or other noxious substances. Upon approaching the patient we are looking at position, skin colour and condition, and observing for any evidence or respirations. As always we want to see if the patient is in fact unresponsive to verbal or painful stimuli (basic BLS approach). In the event that the patient does not respond, we should immediately check for the presence of a carotid pulse. Once the patient is confirmed Vital Signs Absent, we can initiate our resuscitation.
I cannot stress enough, that the single most important thing you will do is QUALITY CHEST COMPRESSIONS. As soon as the patient is confirmed VSA, CPR should be initiated IMMEDIATELY. Our absolute priority, and the one thing that will actually make a difference in the outcome, is ensuring continuous perfusion of the brain and vital organs. Everything else is secondary. Some might make the case for placing defibrillator pads first, but this is not a very good stance to take. Even in the emergency department, in ideal conditions, removal of clothing and placing the pads takes up to one minute and thirty seconds. In short, start CPR before you do anything else.
BLS ARREST
Once good, quality, CPR is in progress, cut clothing, shave hair, etc, and place defibrillator pads. As soon as feasible, pause CPR for a maximum of 10 seconds, and perform a rhythm interpretation. Re-initiate CPR following the rhythm check, you should perform compressions while charging for any defibrillation. As the BLS algorithm dictates, CPR should continue in 2 minute cycles, with a rhythm analysis every 2 minutes, defibrillating as indicated. Following the first analysis/defibrillation, an airway (OPA, NPA, or supraglottic airway) should be placed, and ventilation should be initiated, along with SPO2 and ETCO2 monitoring. Protocols may vary from service to service, however, most places operate on a 4 analysis/defibrillation system. Meaning 4 analyses take place on scene, and then either transport is initiated with continued CPR, or resuscitation is terminated. More on termination of resuscitation later on.
ALS ARREST
The ALS cardiac arrest builds on the BLS arrest, with the addition of some advanced skills and medications. The arrest is initially approached the same way as it is in BLS, with the focus on good CPR, pad placement, and early defibrillation if indicated. There is an additional airway option in the form of the ETT tube, which is a more stable and definitive airway than our other options. Intubation is, however more difficult than other airway management techniques, and a supraglottic airway may be favoured in certain circumstances. Once an airway is established, the next order of business is establishing vascular access in order to administer drugs, as per the ACLS algorithm. The algorithm itself follows one of two pathways: VF/VT or Asystole/PEA. In a patient in VF/VT we are alternating epinephrine 1:10000 and Amiodarone, and potentially utilizing additional medications, while the Asystole/PEA algorithm sees us using epinephrine every 3-5 minutes. There is no hard rule on when to transport or terminate resuscitation, and medical direction provides protocols in this respect.
Termination of Resuscitation:
Rules vary depending on where you work. In Ontario, where I work, TOR is considered in medical arrest in the following circumstances:
Age >18 yrs
Arrest not witnessed by EMS
No defibrillation delivered
No ROSC
In a BLS arrest, medical direction is contacted after the 3rd rhythm analysis if TOR criteria are met. If granted, resuscitation is terminated at this time. In an ALS arrest, TOR is generally considered following the 3rd epinephrine dose in a patient in asystole/PEA, if criteria are met.
Transport and ongoing resuscitation is carried out in all witnessed arrests, pediatric arrests, or those in which defibrillation has occurred.
Some prognostic indicators:
Arrests with a recent timeline, and bystander CPR have a good chance.
V F/VT patients generally do better.
Asystole has a poor prognosis, and PEA has a worse one.
Low ETCO2, even with good CPR is an ominous sign.
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