What happens in the ER is way beyond ACLS. Medics start ACLS to get the patient a better outcome when they get to the ED. In the ED they can do rapid sequence intubation/LMA/cricothyroidotomy/video laryngoscopy, chest tubes, thoracostomy, CV cath placement, pericardiocentesis, thoracotomy, TC pacing, anything open chest/cardiac massage, the last try of solumedrol, etc...
in New York they cover pts with ice.
Also probably not a cardiac Cath lab available in the field, so if you do get a turnaround you can act on a blockage.
In terms of cardiac arrest, an ER simply is not “way beyond ACLS.” What truly has been shown to work is quality CPR and early defibrillation.
I think you’re underestimating the current prehospital EMS scope of practice. Paramedics can have RSI, video laryngoscopy, ultrasound, LMA and other supraglottic airways, cricothyrotomy, needle decompression, defibrillation, pacing, cardioversion, etc. Thoracostomy and cardiac massage are unlikely to be indicated in the situations we’re discussing here. There’s not a cath lab in the ED either.