Abstract 213: Changing Hand Position During Manual Chest Compressions in Cardiac Arrest Affects the Hemodynamic Response: A Clinical Pilot Study

Introduction: Optimal hand position during manual chest compressions (MCC) in cardiac arrest is unknown, but current Guidelines recommend a hand position on the lower half of the sternum. Recent imaging studies suggest that significant inter-individual anatomical differences exist, which might cause altered hemodynamic responses during standard MCC. In this prospective pilot study we wanted to assess the feasibility of utilizing capnography to optimize MCC and identify the optimal hand position in out-of-hospital cardiac arrest (OCHA). Materials and methods: Patients treated by the physician-manned ambulance for non-traumatic OCHA between February and May 2011 were included. Continuous EtCO 2 was measured by sidestream capnography (Lifepak 12, Physio Control, WA, USA). The three minute intervention period was initiated after endotracheal intubation. In the first minute chest compression rate and depth was optimized with hand-position at the recommended point (P0). A two-minute test phase followed; 50 compressions performed at three different sternal positions two cm below P0; P1 midline, P2 two cm to the left, P3 two cm to the right. The hand-position with the highest EtCO 2 value was used during the remaining resuscitation effort. EtCO 2 values are given as means (range), and presented in kPa (1 kPa = 7.5 mmHg). Results: Variations in EtCO 2 values could be documented in 15 OHCA patients. Average EtCO 2 values for 11 patients with cardiac etiology were 4.5 (1.9, 8.3), 5.3 (2.3, 9.6), 5.1 (2.4, 10.3), and 5.1 (2.5, 9.1) for P0 - P3, respectively, and for four non-cardiac etiology patients 4.8 (0.8, 9.7), 5.3 (0.8, 10.7), 5.8 (0.7, 10.3), and 5.1 (0.4, 8.4) for P0 - P3, respectively. The optimal EtCO 2 value was found in P0 in three patients, and in alternative hand positions in 12 patients, with the following distribution; P1: five patients, P2: five patients, P3: one patient, and in one patient P1, P2 and P3 was equally good. Conclusions: Monitoring and optimizing CPR performance and interventions using capnography was feasible. We could demonstrate inter-individual differences affecting hemodynamics, and there were no indications that one specific hand position could be expected to give optimal cardiac output in all patients.