Abstract 40: Tissue Oximetry During Out-of-Hospital Cardiopulmonary Resuscitation
Introduction: Coronary perfusion pressure is a common surrogate marker for myocardial perfusion and the effectiveness of CPR. Peripheral perfusion is far less studied. We sought to evaluate tissue oxygen saturation (StO2) as a surrogate marker for peripheral perfusion during CPR and after return of spontaneous circulation (ROSC) during out-of-hospital cardiac arrest (OOHCA).
Methods: This study was approved by our IRB. EMS physicians responded to cases of cardiac arrest and placed a continuous near infrared tissue oximeter on the thenar eminence of the patient to measure StO2, which was recorded continuously during the resuscitation. Each case was then broken down into 30-second epochs classified as ongoing CPR or post-ROSC. The mean StO2 for each epoch was calculated. A two-sample T test was used to compare the two conditions.
Results: 16 patient encounters were analyzed with a total of 390 epochs, 175 with pulses and 215 during CPR. Patients ranged in age from 34-88 and 10 were male (62.5%). The StO2 average for the epochs during CPR was 50.04 (SD 18.5) and 66.74 (24.6) after ROSC in patients with pulses. A difference of 16.7 was seen between the two conditions (p<0.001).
Conclusion: In this cohort of patients, there was a lower average StO2 reading in patients with CPR being performed when compared to the post ROSC group. While the cause of this difference may be multifactorial, lower tissue oxygen saturation may imply worse peripheral perfusion. Future studies will need to evaluate the cause of this difference and potential impacts it may have on cardiac arrest outcome in the prehospital setting.
- © 2012 by American Heart Association, Inc.