CLARIFICATION
OF ALGORITHM
· On arrival
of the team with the defibrillator, application of the pads and hunt for a
shockable rhythm are top priority.
Assign team members to take over CPR (give this away first), two to the
airway/breathing, one to defibrillator, one to drugs, one to scribe if
available. The team leader then analyses the heart rhythm, and if shockable should instruct the team member on the defibrillator to deliver a defibrillation shock. CPR can be resumed while the defibrillator is charging when using a manual defibrillator, but the team should be cleared from the patient before pressing the button to deliver the shock. CPR should be resumed immediately after defibrillation, there is no need to re-check either the rhythm or pulse until the next 2 minutes of CPR are completed
· Shockable
rhythms = ventricular fibrillation (VF) and pulseless ventricular tachycardia
(pVT).
Non-shockable rhythms = asystole and pulseless electrical activity (PEA). If a non-shockable rhythm is present, check a pulse. If no pulse is present, resume CPR
When team arrive, follow the A-B-C-D of team management
Non-shockable rhythms = asystole and pulseless electrical activity (PEA). If a non-shockable rhythm is present, check a pulse. If no pulse is present, resume CPR
When team arrive, follow the A-B-C-D of team management
- Assign the team roles: one team member to CPR, 2 team members to respiratory management, one team member to the defibrillator, one to IV management, and additional team members should scribe, swop into CPR after 2 minutes, etc.
- Brief the team: instruct the team to do 30
compressions to 2 breaths, repeat for 5 cycles, and to inform team leader when
5th cycle is starting and finishing. Let the team know that after 5 cycles / 2 minutes, CPR will stop, the person doing CPR should swop into a less strenuous job, with CPR to be taken over by a nominated person, and during the pause the team leader will analyse the cardiac rhythm...so called STOP, SWOP AND ANALYSE. Also give team brief overview of patient presentation / background to
arrest
- Check that all team members are performing well: that
CPR is good quality with minimal interruptions, that oxygen is attached to bag-valve-mask
and that patient is easy to ventilate, with chest rising and falling
bilaterally
- Draw up 1st drug: this is epinephrine 1mg
in all types of arrest. Give immediately intravenous access is available in non-shockable rhythms, give after 2nd
shock in shockable rhythms
What drugs are given in cardiac arrest, and when should they be given?
- Epinephrine 1mg is given immediately in asystole / PEA, and is then repeated every 3-5 minutes for the duration of the arrest. No other drug is used in these rhythms
- Epinephrine 1mg is also the first drug given in the shockable rhythms, but is not given until the rhythm becomes refractory ie after the second shock. It is again given every 3-5 minutes (every second cycle in practice) for the duration of the arrest
- In shockable rhythms only, either amiodarone or lignocaine can be given after the 3rd shock (300mg amiodarone in D5 IV push; lignocaine 1.0-1.5mg/kg IV push) and again after the 5th shock (150mg amiodarone in D5 IV push, lignocaine 0.5-0.75mg/kg IV push). The drug sequence in shockable rhythms is therefore as follows:
An easy way to remember what needs to be done during an arrest is:
- Make sure CPR is ongoing at all times, but if a defibrillator arrives, prioritize hunting for a shockable rhythm and delivering shock. If you have a second rescuer, CPR can be continued while you are organizing defibrillator
- As soon as the team arrive, do the A-B-C-D of team management. Organizing your team will probably take up most of the first two minutes of the arrest.
- After the second analysis +/- shock, ensure the first drug is given, and consider reversible causes.
- After every rhythm analysis, as soon as CPR resumes, consider giving the next drug in the algorithm sequence.
What are the reversible causes, and how do we manage them?
Reversible causes, also known as the Hs and Ts, should be considered during the second 2 minutes of the arrest algorithm, or earlier as you become more practiced at arrest management. An easy way of remembering them is:
- Stand at end of bed and watch the chest rise. If it rises bilaterally,tension pneumothorax is unlikely. Confirm that tension pneumothorax is not present by auscultating breath sounds and ascertaining whether the trachea is central. Make sure that 100% oxygen is attached to the bag-valve-mask to reverse hypoxia, and good ventilation will reverse the respiratory component of acidosis. Confirm that the patient is not profoundly acidotic with a venous blood gas (VBG)
- "Fluids in, fluids out". Hang a bag of normal saline and give in 250-500ml boluses to reverse any potential hypovolaemia. More fluid may be indicated if the patient was hemodynamically compromised pre-arrest. "Fluids out" includes blood samples (VBG will confirm potassium levels, pH and lactate; point-of-care glucose can be done at the bedside) and urine sample (a catheter specimen may be dipped for toxins if there is any suspicion that the patient has taken pharmacological agents that may contribute to the cardiac arrest)
- The 4 Ts: thrombus, tamponade and temperature and trauma - consider PE (ask for d-dimers on pre-arrest blood sample) or coronary thrombus (request troponin-I on pre-arrest blood sample; perform ECG if ROSC is achieved). If tamponade is suspected on history or examination, organise a bedside echo / ultrasound. Palpation of poor femoral pulses during CPR is an unreliable sign of either tamponade, tension pneumothorax or hypovolaemia, but may be done while waiting for ultrasound. Tympanic temperature may reveal hypothermia, which is associated with irritable myocardium and arrest. Rewarming is indicated in such cases. Manage trauma if present as per guidelines.
FYI: the following management of Hs and Ts are not part of a basic ACLS course, but are useful to know. Seek expert help unless you are proficient in the following techniques:
- Tension pneumothorax is managed in the first instance with needle decompression - a 14G cannula is inserted into the 2nd intercostal space just above the 3rd rib in the mid-clavicular line to decompress the chest, followed by a definitive chest drain. The alternative locations for placement of the needle in needle decompression are the 4th intercostal space in the anterior axillary line, or 4th intercostal space in the mid-axillary line. Insertion in these cases should be just above the 5th rib to avoid puncturing the intercostal bundle.
- In acidosis, ventilatory correction is sufficient unless the acidosis is profound (<7.1 on arterial blood gas). If profound acidosis is present, use of NaHCO3 may be considered (seek expert help)
- Hyperkalaemia requires the use of calcium chloride to protect the myocardium; glucose-insulin infusion or sodium bicarbonate infusion to reduce plasma potassium can be considered, also removal of potassium from the body. In hypokalaemia, potassium should be replaced carefully.
- Toxin overdose requires specialist management and possibly administration of antidote - liaise with local poison centre.
- Tamponade may require needle pericardiocentesis with cardiothoracic follow-through.
In cardiac arrest, when should you check a pulse?
- If patient becomes responsive during resuscitation
- If ETCO2 rises sharply to between 35-45mm Hg
- If a rhythm changes: CHANGE OF RHYTHM: CHECK PULSE
- If a potentially perfusing PEA rhythm is present at the "stop, swop and analyse" step
Candidates are often confused about pulse checks during arrest rhythms. Broadly if a patient starts the arrest with ventricular fibrillation which is pulseless, if this rhythm persists at the 2-minute check, there is no need to check a pulse again. The same applies to pulseless ventricular tachycardia, however with a change of rhythm to ventricular tachycardia it is reasonable to do a quick pulse check. Presence of a potentially perfusing rhythm other than pVT requires that the pulse be checked each time assessment is carried out.
In summary: when you stop, swop and analyse, you will see one of 4 situations on the monitor:
What about polymorphic ventricular tachycardia?In summary: when you stop, swop and analyse, you will see one of 4 situations on the monitor:
- Ventricular fibrillation (VF): as the patient is already in established arrest, there is no chance of achieving return of spontaneous circulation (ROSC) with this rhythm. Resume CPR while charging, clear to deliver shock, then continue CPR for 2 minutes until the next rhythm check.
- Ventricular tachycardia (VT): if the patient was in pulseless ventricular tachycardia (pVT) at the onset of the arrest, the chances of a pulse returning when the same rhythm persists are slim. With persistent VT, it is correct to resume CPR while charging - defibrillate - continue CPR without checking a pulse. However, this often confuses candidates because technically it is possible to have a pulse with VT. If in doubt, check a pulse for no more than 10 seconds; if no pulse present resume CPR while charging - defibrillate - continue CPR
- Asystole: "flatlining". Once it has been established that there are no loose leads, and that the patient is pulseless, the treatment for this rhythm is: resume CPR, administer epinephrine 1mg every 3-5 minutes and consider reversible causes. Increasing the gain on the monitor while CPR is ongoing and stopping briefly to re-analyse ensures that fine ventricular fibrillation is not being missed. If asystole persists on further rhythm analysis, further pulse checks are not indicated - this simply delays resumption of CPR.
- Pulseless Electrical Activity (PEA): if a rhythm does not fit into any of the above categories, and the patient remains pulseless, the arrest is classified as PEA and is managed under the same algorithm as asystole. Because PEA is associated with perfusing rhythms, pulse checks should be carried out to establish arrest at each rhythm analysis. Pausing to define further what is on the monitor is not needed and delays return to CPR. If it's not VF, pVT, or asystole and the patient is in cardiac arrest, manage as PEA
If your patient is in cardiac arrest, polymorphic ventricular tachycardia is managed in the same algorithm as VF and pVT (monomorphic). The only difference in management is that MgSO4 1-2g IV may be considered as pharmacological therapy instead of amiodarone in Torsades de Pointes (ie polymorphic VT associated with a long QT interval)
