Introduction and Purpose: Palpating peripheral pulsations has been shown to be a non-specific and non-sensitive strategy for assessment of life-supporting output as in ROSC.(1) Non-invasive blood pressure measurement take too long, particularly on the low-pressure conditions.(2) Early use of arterial lines (i.e. femoral or radial artery catheters) in mature in-hospital settings can optimize care by showing curves and shortening pause time.(3)

Materials and methods: We retrospectively reviewed our database of in-hospital resuscitation attempts (2015–2018) in which the Philips MRx defibrillator-monitor was used. In this period, the resuscitation team procedures were unchanged. We hypothesize that an arterial line should be independently associated with very brief rhythm check pauses, regardless of rhythm found. IRB approval with waived informed consent was received.

Results: In the 603 assessable rhythm pauses, those with an arterial line (n=66) were all more rapid than those without (9±7sec versus 16±16sec). The simple algorithm of “stop compressions” and an arterial curve dropping to “flat line” is unambivalent. This improvement remained valid in the more-difficult-to-assess “potentially perfusing” rhythm (n=366: 10±7sec respectively 20±19sec). 
Placement was typically rapid and usable within 6min. With an art line, SBP ≥ 60mmHg was deemed ROSC and vasopressors titrated (i.e. 0.2mg epinephrine bolus) instead of reinstatement of compressions and epinephrine per mg. 

Conclusions: Early placement of an arterial line (i.e. femoral or radial artery) during early, ongoing CPR supports rapid rhythm assessments, recognition of ROSC, titration of epinephrine and is to be considered non-controversial and perhaps standard-of-care in all mature in-hospital CPR settings.
References:
1.	Brearley S, et al. Ann R Coll Surg Engl. 1992;74:169–71.
2.	Meaney  PA, et al. Circulation. 2013;128:417-35. 
3.	Hoppu S, et al. Resuscitation. 2011;82:1460-3.

3 - Real assessment of ROSC requires an arterial catheter during ongoing CPR.