Background: The aim of the present study was to determine whether instructors could accurately assess chest compression quality visually, considering the association between chest compression depth and rate.

Methods and Results: In this prospective, observational study, the quality of chest compressions performed by a simulated actor in a video was visually assessed by certified instructors. The film consisted of 14 case scenarios, each including a combination of depth (2 patterns: adequate, 5–6 cm; and inadequate, <5 cm) and rate (7 categories: compressions 90–150 times/min in increments of 10 times/min). The participants evaluated whether the compression depth was adequate, deep, or inadequate; and whether the compression rate was appropriate, fast, or slow. Of 198 instructors, 56% of participants misidentified adequate depth as deep at a chest compression rate of 120/min (the tendency toward this response increased as chest compression rate increased), and 64.1% of participants incorrectly determined 130/min to be appropriate. On generalized linear mixed-effects model analysis, perceived chest compression depth and rate were significant factors for a correct response (P<0.01, both). A significant interaction between chest compression depth and rate was observed (P<0.01).

Conclusions: In the visual assessment of chest compression quality, recognition of chest compression depth was closely associated with compression rate. Misidentification of adequate chest compression depth as deep increased as the compression rate increased.