title: Quantitative waveform measures of the electrocardiogram as continuous physiologic feedback during resuscitation with cardiopulmonary bypass.
abstract: BACKGROUND
  There are few if any real-time physiologic measures that currently provide feedback during resuscitation from cardiac arrest. Such measures could be used to guide therapy not simply based on process guidelines but on the physiologic response of the patient from moment to moment. To this end, we applied an existing technology - quantitative waveform measures (QWMs) of the ventricular fibrillation (VF) electrocardiogram (ECG) - as a continuous measure of myocardial response to reperfusion with cardiopulmonary bypass (CPB) after prolonged cardiac arrest.
  
  
  METHODS
  Sixteen domestic, mixed-breed swine were sedated, anesthetized and paralyzed. Mechanical ventilation with room air was provided. Large diameter bypass catheters were placed in the right external jugular vein and right femoral artery for cardiopulmonary bypass (CPB). VF was induced with a 3-s 100mA transthoracic shock and left untreated for 15, 20, 25, or 30min, followed by 10min of centrifugal pump CPB (Bard CPS). Continuous Lead II ECG was recorded with an electronic data acquisition system (Power Lab, ADInstruments). Four QWMs representing 4 signal characteristics of the VF ECG were calculated in 5-s windows throughout the course of untreated VF and resuscitation with CPB.
  
  
  RESULTS
  Four animals were assigned to each VF duration group. QWM recovery was inversely correlated with untreated VF duration, and was drastically reduced above 20min of untreated VF. Return of spontaneous circulation (ROSC) was highly unlikely after 20min of untreated VF.
  
  
  CONCLUSIONS
  QWMs of the VF ECG provided a real-time metric of myocardial electrophysiologic response to reperfusion with CPB. Resuscitation from greater than 20min of untreated cardiac arrest was unlikely. QWMs may be useful for titrating CPB duration before defibrillation and assessing CPR quality independently of process guidelines.
authors.affiliation: University of Pittsburgh, Pittsburgh, PA 15260, USA. salcidodd@upmc.edu
authors.forename: David D
authors.initials: DD
authors.lastname: Salcido
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Sherman
authors.forename: Greggory
authors.initials: G
authors.lastname: Housler
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Teng
authors.forename: Eric S
authors.initials: ES
authors.lastname: Logue
authors.forename: James J
authors.initials: JJ
authors.lastname: Menegazzi
mesh_terms: D000818:Animals; D002315:Cardiopulmonary Bypass; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000379:methods*; D025461:Feedback, Physiological; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D008991:Monitoring, Physiologic / Q000295:instrumentation; D011897:Random Allocation; D012680:Sensitivity and Specificity; D034421:Sus scrofa; D013552:Swine; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology