Improved haemodynamics with increased compression-decompression rates during ACD-CPR in pigs.

The haemodynamic effects of variations in the compression-decompression frequency, 60, 90 and 120 min(-1) during ACD-CPR, were tested in a randomized cross-over design during ventricular fibrillation (VF) in 12 anaesthetized pigs (17-22 kg) using an automatic hydraulic chest compression-decompression device. There were significant increases with increasing frequency for mean (+/- S.D.) carotid blood flow (17 +/- 5, 25 +/- 9 and 36 +/- 12 ml min(-1), transit time flow probe), cerebral blood flow (17 +/- 7, 30 +/- 17 and 40 +/- 13 ml min(-1) 100 g(-1), radionuclide microspheres) and mean aortic pressure (34 +/- 8, 37 +/- 10 and 43 +/- 7 mmHg), respectively. Myocardial blood flow (radionuclide microspheres) and diastolic coronary perfusion pressure, CPP, increased significantly from 60 to 90 min(-1) with no further significant increase to 120 min(-1) (28 +/- 13, 46 +/- 23 and 49 +/- 19 ml min(-1) 100 g(-1) and 25 +/- 8, 31 +/- 11 and 32 +/- 9 mmHg, respectively). Renal and hepatic blood flow also increased with increasing rate. No significant differences in the expired CO2 levels were observed. In conclusion increasing the compression-decompression frequency from 60 to 90 and 120 min(-1) improved the haemodynamics during ACD-CPR in a pig model with VF.