Abstract Body:
Introduction: Previously, some investigators have reported that static abdominal binding (AB) is adjunctive to sternal piston-based CPR. Others have found that it is not. Circumferential thoracic CPR (CT-CPR) is an alternative pump mechanism and may have enhanced hemodynamics and safety. We have previously reported that addition of pulsatile abdominal counter-constriction (ACC) further improves the hemodynamics of CT-CPR. Simple AB requires less energy than ACC, however the efficacy of AB as an adjunct to CT-CPR has not been studied.

Hypothesis: One of the CTA-CPR abdominal adjuncts, ACC or AB, may be associated with greater indicators of hemodynamics.

Methods: Ventricular fibrillation was induced in female Yorkshire swine (n = 3, 30 kg). CPR was provided by a pneumatic CT-CPR prototype and circumferential pneumatic bands. Forty-five-second epochs of CT-CPR with ACC or AB were performed. Aortic (Ao) and right atrial (RA) pressures were measured using micromanometer catheters and coronary perfusion pressure (CPP) was calculated. The change in CPP (Delta-CPP) from the beginning to the end of each treatment epoch was the principal indicator of hemodynamics. Results from all experiments were grouped by treatment type and subjected to a paired t-test.

Results: The delta perfusion pressures are shown in the Figure. Final aortic pressures averaged 62 and 37mmHg for static AB and pulsatile ACC respectively. Final right atrial pressures averaged 45 and 8mmHg for static AB and ACC respectively. These yielded final CPPs of 17 and 29mmHg for static AB and pulsatile ACC respectively. Pulsatile counter-constriction was associated with much higher final CPP in every treatment pair.

Conclusion: CT-CPR with adjunctive abdominal binding consistently increased both Ao and RA pressures. However, compared to AC, AB showed a much greater RA pressure increase, resulting in lower CPPs and Delta-CPPs. Abdominal counter-constriction may be superior to abdominal binding as an adjunctive modality in circumferential thoracic CPR. These results are similar to those reported by JT Niemann and JM Criley in 1984 using piston-based CPR. They observed that it appeared to raise vascular pressures but lower CPP.