Menegazzi JJ et al, 1993, USA | 5 rescuers performing CPR on 7 swine with induced cardiac arrest. CPR performed with two fingers (TF) or two thumbs (TT) | Randomised crossover trial | Diastolic blood pressure | Higher in TT group (21.8 v 18.5; p <0.001) | No measure of force applied during techniques Differences statistically relevant, ?not clinically |
| | | Systolic blood pressure | Higher in TT group (59.4 v 41.6; p <0.001) | |
| | | Mean arterial blood pressure | Higher in TT group (34.2 v 26.1; p <0.001) | |
| | | Coronary perfusion pressure | Higher in TT group (15.1 v 12.2; p <0.001) | |
Houri PK et al, 1997, USA | Swine with induced cardiac arrest. CPR performed with two fingers (TF) or two thumbs (TT) | Randomised crossover trial | Diastolic blood pressure | No significant difference | Sternal compression force achieved was lower in the two fingers group when investigators tried to standardise this component |
| | Systolic blood pressure | 25% increase with and 57% increase in two thumbs group when no force feedback was given |
Dorfsman ML et al, 2000, USA | 21 rescuers performing CPR on adapted manikin. CPR performed with two fingers (TF) or two thumbs (TT) | Randomised crossover trial | Diastolic blood pressure | Higher in TT group (mean 17.6 v 12.5 p <0.001) | Only verbal instructions given in performing TT technique—all rescuers experienced in TF technique |
| | Systolic blood pressure | Higher in TT group (mean 68.9 v 44.8 p <0.001) |
| | | Mean arterial blood pressure | Higher in TT group (mean 35.3 v 23.3p <0.001) | |
| | | Perfusion pressure | Higher in TT group (mean 51.4 v 31.2p <0.001) | |
Whitelaw CC et al, 2000, USA | 209 subjects performing CPR on manikin. CPR performed with two fingers (TF) or two thumbs (TT) | Randomised crossover trial | Adequacy of CPR on skill guide | No significant difference—40 participants produced adequate CPR using TT (95% CI 14 to 25%) and 38 using TF (95% CI 13 to 24%). TT produced more than 40 too shallow compressions in 40 participants compared with 15 in the TF group (p <0.005) | Heterogenous group of participants with varying levels of experience. 71% of participants failed to give more than 60 adequate compressions in 2 minute period |