General: 2 things that really work in cardiac arrest are from Basic Life Support (BLS):

• Compressions - get a perfusing pressure to the heart which then drops off the second you stop; it takes numerous compressions to return to that level - BLS says goal 60%-80% compression fraction. 
• Defibrillation. 

Beyond BLS: 

• Data (Circulation 2009) that suggests that higher your compression fraction (percentage time spent on chest) the higher your rate of ROSC. 
• There is an association between better ROSC rates in compression rates 120-140 compared to BLS/ACLS advised rate of 100-120. (Circulation 2017). 
• Early defibrillation have much higher survival rate. 

Beyond ACLS: most lives saved come from BLS interventions. 

• Epinephrine has improved ROSC in prehospital setting (JAMA 2012) but at the cost of loss of 1 month survival and worsening in neurological function on discharge
• A trial (Circulation 2017) shows slightly improved survival in patients with epinephrine given early in hospital cardiac arrest (statistically significant but of questionable clinical significance).
• Intubation in out of hospital cardiac arrest (OHCA) was shown to have no improvement in ROSC compared to BVM (JAMA 2018 RCT). 
• Intubation for In hospital cardiac arrest has worse outcomes. 
• The LUCAS and other mechanical devices may have value in the field where they are limited number of hands but may not have value in hospital. 
• A non-inferiority trial (2017, European Heart Journal) achieved statistical non inferiority for the LUCAS and rates of ROSC fell from 50% in manual CPR to 35% in mechanical CPR; also adverse effects from mechanical CPR included liver laceration. 
• Arterial Lines in cardiac arrest are underrated as the physiology below suggests that patients with a high coronary perfusion pressure (diastolic pressure > 25) do better overall. 

References:

Patel et al, Association between prompt defibrillation and epinepherine treatment with long term survival after in-hospital cardiac arrest, Circulation, 2017.

Kilgannon et al, Association between chest compression rates and clinical outcomes following in-hospital cardiac arrest at an academic tertiary hospital, Circulation, 2017.

Christensen et al, Chest Compression Fraction Determines Survival in Patients With Out-of-Hospital Ventricular Fibrillation, Circulation. 2009;120:1241-1247

Jabre P et al. Effect of bag-mask ventilation vs endotracheal intubation during cardiopulmonary resuscitation on neurological outcome after out-of-hospital cardiorespiratory arrest: A randomized clinical trial. JAMA 2018 Feb 27; 319:779.

Woster et al, Safety of mechanical chest compression devices AutoPulse and LUCAS in cardiac arrest: a randomized clinical trial for non-inferiority, European Heart Journal 2017.

Paradis et al, Coronary perfusion pressure and the return of spontaneous circulation in human cardiopulmonary resuscitation, JAMA, 1990.

Patel et al, Association between prompt defibrillation and epinepherine treatment with long term survival after in-hospital cardiac arrest, Circulation, 2017.