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Table 1 CPR performance variables with and without feedback (Mean ± SEM [95% Confidence Interval])

From: A counterbalanced cross-over study of the effects of visual, auditory and no feedback on performance measures in a simulated cardiopulmonary resuscitation

Quality of CPR Indicator N = 15

No feedback

Auditory Feedback

Visual Feedback

Percent Correct Compressions [correct depth, rate, and release]

44.5 ± 8.1a (27.1-61.8)

65.4 ± 7.6 (40.1-72.7)

78.1 ± 8.2 (60.4-95.7)

N who achieved 90% or better

2 (13%)

1 (6%)

9 (60%)

Average Rate of Compressions [number per minute]

96.5 ± 0.7 (95.2-97.8)

87.9 ± 0.5 b (86.9-88.9)

94.9 ± 0.7 (93.5-96.4)

N with rate between 90 and 120 c

8 (53%)

8 (53%)

8 (53%)

Percent compressions with 38 or more mm depth

55.5 ± 8.9 d (36.4-74.7)

80.5 ± 6.0 (67.6-93.4)

95.4 ± 1.9 (91.3-99.5)

N who achieved 90% or better

3 (20%)

4 (27%)

13 (86%)

Average depth of compressions (mm)

39.2 ± 0.5 e (35.3-43.1)

41.4 ± 0.3 38.4-44.3)

42.2 ± 0.3 (38.8-45.5)

N who achieved 38-50 mm

9 (60%)

13 (86%)

13 (86%)

Percent compressions without full release of pressure

0.7 ± 0.3 (0.02-1.3)

23.4 ± 6.2f (10.1-36.8)

0.8 ± 0.5 (0.44-2.0)

N with 5% or more of compressions without full release

0

11 (73%)

0

Average duty-cycle

46.1 ± 2.1 (41.5-50.7)

39.4 ± 1.6g (35.9-42.9)

42.5 ± 1.1 (40.2-44.8)

N with range .30-.50

14 (93%)

13 (86%)

15(100%)

  1. a No feedback yielded lower percentage of correct compressions than did visual feedback (p = 0.01).
  2. b Auditory Feedback yielded slower rate than did no and visual feedback (p < 0.05).
  3. c Guidelines recommend 100 per minute [2]; we report range as no one subject delivered exactly 100 compressions per minute.
  4. d No feedback yielded lower percentage of adequate compressions (38-50 mm) than did auditory and visual feedback (p < 0.05).
  5. eNo feedback yielded shallower average depth of compressions than did auditory and visual feedback (p < 0.05).
  6. f Auditory feedback yielded a greater percentage of compressions that were not fully released than did no and visual feedback (p < 0.05).
  7. g Auditory feedback yielded a smaller duty cycle than did no feedback (p < .05).