Source: Wikipedia (search term "precordial thump"), Merckmanuals,
- The procedure is outside the scope of first-aid treatment and requires, at minimum, training in advanced cardiac life support (ACLS). Incorrect application of this technique can result in fracture of the sternum/rubs or 'commotio cordis' aka cardiac arrest due to blunt trauma. This procedure if done incorrectly can lead to asystole or a more fatal arrhythmia.
- In a normal adult, the energy range involved in the precordial thump is ~5 joules which is 5-10 times below that associated with commotio cordis. [Aside: This was an interesting piece of information because I considered the possibility of getting an athlete, if present, to perform this procedure for me to increse the energy of the thump, but this then increases the risk of inducing commotio cordis.]
The force has to be applied within this 'risk window' (initial repolarisation of the ventricles) in order to result in commotio cordis. This window is incresed during physical activity because the number of heart beats will increase without significantly altering the rate of repolarisation. Ie. There are more chances for this phenomenon to occur. It is thought that at least 50 joules is necessary to trigger this event. - It is effective only if used near the onset of VF or pulseless VT.
ie. Only appropriate when the arrest is witnessed or monitored. - ~ 25% of patients in cardiac arrest will
regain cardiac function (Scherf and Bornemann, 1960).
No evidence of benefit in unwitnessed cardiac arrests. - May only be attempted once or twice during the onset of
cardiac arrest.
- Force is delivered to the junction of the middle and lower third of the sternum with a clenched fist held 20 to 25 cm above the chest.
- After this, immediately continue with other ACLS skills, including CPR, ACLS drugs, and defibrillation, as appropriate.
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