We didn't create the Chain of Survival overnight, in fact it's taken centuries of innovation to make it from flogging patients or rolling them on wine barrels to high performance CPR.

Although hopefully our modern experiments won't seem so surreal in 150 years. 1/x

One of the most concerted efforts to study OHCA/CPR improvements happened via the Resuscitation Outcomes Consortium (ROC).

This allowed 11 different regions to collate their data in a systematic way in order to study different OHCA interventions. https://pubmed.ncbi.nlm.nih.gov/17907019/ 

The Prehospital Resuscitation IMpedance valve and Early vs Delayed analysis (PRIMED) measured two interventions.

Q1: Did an Impedance Threshold Device (ITD) improve survival?

A1: No. https://www.nejm.org/doi/10.1056/NEJMoa1010821?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed

PRIMED Q2: After EMS is on scene, does the immediacy of the first rhythm analysis and defibrillation matter?

A2: No. Remember, electricity saves lives, but waiting an additional 2 minutes for a shock didn't change survival. https://www.nejm.org/doi/full/10.1056/nejmoa1010076

The Amiodarone, Lidocaine, Placebo Study (ALPS) compared two heart rhythm medications to a placebo. The thought was that once you shock the heart back into a normal rhythm the drugs would keep it from re-fibrillating.

A: No difference. https://www.nejm.org/doi/full/10.1056/nejmoa1514204

During OHCA EMS tries to give drugs via an IV, but sometimes the patient has no access so they drill a hole into bone. A post hoc analysis of ALPS looked to compare if the route of drug administration mattered.

A: No, but underpowered https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.119.042240

The Pragmatic Airway Resuscitation Trial (PART) compared a traditional endotracheal intubation (tube in the trachea) to a laryngeal tube (tube blocks the esophagus, forcing oxygen into lungs).

A: Survival to 72 hours better with laryengeal tube https://jamanetwork.com/journals/jama/fullarticle/2698491

Continuous Chest Compressions vs AHA Standard CPR of 30:2 (CCC) compared mixing ventilations continuously with compressions to alternating 30 chest compressions with every 2 ventilatons.

A: No difference in survival https://www.nejm.org/doi/full/10.1056/nejmoa1509139

We interupt this thread so that Bruno (and I) can get some shut eye. Have no fear, I'll be back.

EMSers I see you...I'll probably add to this thread all week as it feels too big for a single day. Feel free to add your favorite OHCA study below!