Abstract 39: Intrathoracic Pressure Regulation During and After Cardiopulmonary Resuscitation: A Feasibility Study
Objective: Reduction of intrathoracic pressures to -10 cm H2O during the decompression phase of cardiopulmonary resuscitation (CPR) increases cardiac preload, lowers intracranial pressures, and increases circulation and survival rates in pigs undergoing standard CPR. In this proof of concept study, we tested the hypothesis that augmentation of negative intrathoracic pressure during standard (S) CPR with intrathoracic pressure regulation (IPR) providing continuous negative intrathoracic pressure of -10 cm H2O between positive pressure ventilations will improve circulation, using end tidal (ET) CO2 as a non-invasive surrogate of organ perfusion, in patients receiving S-CPR.
Methods: In this first clinical evaluation of IPR (CirQLatorTM, Advanced Circulatory Systems Inc, Roseville, MN) paramedic supervisors in Toledo OH performed CPR, applied IPR in 12 adult patients, and measured ETCO2, blood pressure and O2 saturation upon return of spontaneous circulation (ROSC) rates. IPR was continued after ROSC to help maintain perfusion. Values are expressed as mean ± SEM and statistical significance was determined by a paired Student's t-test. ETCO2 and blood pressure are expressed in mmHg.
Results: IPR was used together with S-CPR to treat cardiac arrest in 12 patients: mean age 64 ± 3; 4 were male and the initial recorded rhythms were ventricular fibrillation (n=2), pulseless electrical activity (n=3), and asystole (n=7). Time from the initial 911 call to IPR application was 16±1 min. Initial ETCO2 when IPR was applied was 21± 3. Maximum ETCO2 during CPR was 44 ± 4, (p < 0.001 compared with initial ETCO2). There was ROSC in 9/12 patients: 3 patients with asystole did not have ROSC. Time from IPR application to ROSC was 16 ± 3 minutes. Systolic/diastolic blood pressures immediately after ROSC were 126 ±13/72 ± 8. O2 saturation at ROSC was 96 ± 1%. IPR was used in 8/9 patients post ROSC for 8 ± 3 min. There were no observed adverse events.
Conclusion: Clinical application of IPR during CPR increased ETCO2 values and resulted in ROSC in 9/12 patients, providing first clinical proof-of-concept that this new non-invasive technology increases circulation during CPR. Based upon these positive data, further study of IPR in patients in cardiac arrest is warranted.
- © 2011 by American Heart Association, Inc.