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Introduction: A benefit of in-hospital cardiac arrest is the opportunity for rapid initiation of “high-quality” chest compressions as defined by current American Heart Association (AHA) adult guidelines as a depth 2-2.4 inches, full chest recoil, rate 100 -120 per minute, and minimal interruptions with a chest compression fraction (CCF) ≥ 60%. The goal of this study was to assess the effect of audiovisual feedback on the ability to maintain high-quality chest compressions as per 2015 updated guidelines.Methods: Ninety-eight participants were randomized into four groups. Participants were randomly assigned to perform chest compressions with or without use of audiovisual feedback (+/- AVF). Participants were further assigned to perform either standard compressions with a ventilation ratio of 30:2 to simulate cardiopulmonary resuscitation (CPR) without an advanced airway or continuous chest compressions to simulate CPR with an advanced airway. The primary outcome measured was ability to maintain high-quality chest compressions as defined by current 2015 AHA guidelines. Results: Overall comparisons between continuous and standard chest compressions (n=98) were without significant differences in chest compression dynamics (p’s >0.05). Overall comparisons between +/- AVF (n = 98) were significant for differences in average rate of compressions per minute (p= 0.0241) and proportion of chest compressions within guideline rate recommendations (p = 0.0084). There was a significant difference in the proportion of high quality-chest compressions favoring AVF (p = 0.0399). Comparisons between chest compression strategy groups +/- AVF were significant for differences in compression dynamics favoring AVF (p’s < 0.05).  Conclusion: Overall, AVF is associated with greater ability to maintain high-quality chest compressions per most-recent AHA guidelines. Specifically, AVF was associated with a greater proportion of compressions within ideal rate with standard chest compressions while demonstrating a greater proportion of compressions with simultaneous ideal rate and depth with a continuous compression strategy.

Background: Inadvertent hyperventilation is associated with poor outcomes from traumatic brain injury (TBI). Hypocapnic cerebral vasoconstriction is well described and causes an immediate and profound decrease in cerebral perfusion. The hemodynamic effects of positive-pressure ventilation (PPV) remain incompletely understood but may be equally important, particularly in the hypovolemic patient with TBI. Objective: Preliminary report on the application of a previously described mathematical model of perfusion and ventilation to prehospital data to predict intrathoracic pressure. Methods: Ventilation data from 108 TBI patients (76 ground transported, 32 helicopter transported) were used for this analysis. Ventilation rate (VR) and end-tidal carbon dioxide (PetCO2) values were used to estimate tidal volume ( VT). The values for VR and estimated VT were then applied to a previously described mathematical model of perfusion and ventilation. This model allows input of various lung parameters to define a pressure-volume relationship, then derives mean intrathoracic pressure (MITP) for various VT and VR values. For this analysis, normal lung parameters were utilized. Separate analyses were performed assuming either fixed or variable PaCO2-PetCO2 differences. Ground and air medical patients were compared with regard to VR, PetCO2, estimated VT, and predicted MITP. Results: A total of 10,647 measurements were included from the 108 TBI patients, representing about 13 minutes of ventilation per patient. Mean VR values were higher for ground patients versus air patients (21.6 vs. 19.7 breaths/min; p < 0.01). Estimated VT values were similar for ground and air patients (399 mL vs. 392 mL; p = NS) in the fixed model but not the variable (636 vs. 688 mL, respectively; p < 0.01). Mean PetCO2 values were lower for ground versus air patients (30.6 vs. 33.8 mmHg; p < 0.01). Predicted MITP values were higher for ground versus air patients, assuming either fixed (9.0 vs. 8.1 mmHg; p < 0.01) or variable (10.9 vs. 9.7 mmHg; p < 0.01) PaCO2-PetCO2 differences. Conclusions: Predicted MITP values increased with ventilation rates. Future studies to externally validate this model are warranted. [ABSTRACT FROM AUTHOR]