Excessive chest compression rate is associated with insufficient compression depth in prehospital cardiac arrest
Monsieurs KG et al. – This study showed an association between higher compression rates and lower compression depths. Avoiding excessive compression rates may lead to more compressions of sufficient depth.Methods
- In patients undergoing prehospital cardiopulmonary resuscitation by health care professionals, chest compression rate and depth were recorded using an accelerometer (E–series monitor–defibrillator, Zoll, USA).
- Compression depth was compared for rates <80/min, 80–120/min and >120/min.
- A difference in compression depth ≥0.5cm was considered clinically significant.
- Mixed models with repeated measurements of chest compression depth and rate (level 1) nested within patients (level 2) were used with compression rate as a continuous and as a categorical predictor of depth.
- Results are reported as means and standard error (SE).
- One hundred and thirty–three consecutive patients were analysed (213409 compressions).
- Of all compressions 2% were <80/min, 62% between 80–120/min and 36% >120/min, 36% were <4cm deep, 45% between 4 and 5cm, 19% >5cm.
- In 77 out of 133 (58%) patients a statistically significant lower depth was observed for rates >120/min compared to rates 80–120/min, in 40 out of 133 (30%) this difference was also clinically significant.
- The mixed models predicted that the deepest compression (4.5cm) occurred at a rate of 86/min, with progressively lower compression depths at higher rates.
- Rates >145/min would result in a depth <4cm.
- Predicted compression depth for rates 80–120/min was on average 4.5 (SE 0.06)cm compared to 4.1 (SE 0.06)cm for compressions >120/min (mean difference 0.4cm, P<0.001).
- Age and sex of the patient had no additional effect on depth.