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Aim The optimal head and thorax position after return of spontaneous circulation (ROSC) following cardiac arrest (CA) is unknown. This study examined whether head and thorax elevation post-ROSC is beneficial, in a porcine model. Methods Protocol A: 40 kg anesthetized pigs were positioned flat, after 7.75 min of untreated CA the heart and head were elevated 8 and 12 cm, respectively, above the horizontal plane, automated active compression decompression (ACD) plus impedance threshold device (ITD) CPR was started, and 2 min later the heart and head were elevated 10 and 22 cm, respectively, over 2 min to the highest head up position (HUP). After 30 min of CPR pigs were defibrillated and randomized 10 min later to four 5-min epochs of HUP or flat position. Multiple physiological parameters were measured. In Protocol B, after 6 min of untreated VF, pigs received 6 min of conventional CPR flat, and after ROSC were randomized HUP versus Flat as in Protocol A. The primary endpoint was cerebral perfusion pressure (CerPP). Multivariate analysis-of-variance (MANOVA) for repeated measures was used. Data were reported as mean ± SD. Results In Protocol A, intracranial pressure (ICP) (mmHg) was significantly lower post-ROSC with HUP (9.1 ± 5.5) versus Flat (18.5 ± 5.1) (p Conclusion Post-ROSC head and thorax elevation in a porcine model of cardiac arrest resulted in higher CerPP and lower ICP values, regardless of VF duration or CPR method. IACUC Protocol Number 19-09.

Aim Controlled sequential elevation of the head and thorax (CSE) during active compression–decompression (ACD) CPR with an impedance threshold device (ITD) augments cerebral (CerPP) and coronary (CorPP) perfusion pressures. The optimal CSE is unknown. Methods After 8 minutes of untreated VF, 40 kg anesthetized female pigs were positioned on a customized head and thorax elevation device (CED). After 2 min of automated ACD + ITD-16 CPR to ‘prime the system’, 12 pigs were randomized to CSE to the highest CED position over 4-min or 10-min. The primary outcome was CerPP after 7 minutes of CPR. Secondarily, 24-sec (without a priming step) and 2-min CSE times were similarly tested (n = 6 group) in a non-randomized order. Values expressed as mean ± SD. Results After 7 min of CPR, CerPPs were significantly higher in the 4-min vs 10-min CSE groups (53 ± 14.4 vs 38.5 ± 3.6 mmHg respectively, p = 0.03) whereas CorPP trended higher. The 4-min CSE group achieved 50% of baseline (50% BL) CerPP faster than the 10-min group (2.5 ± 1.2 vs 6 ± 3.1 minutes, p = 0.03). CerPP values in the 2-min and 4-min CSE groups were significantly higher than in the 24-sec group. With CSE, CerPPs and CorPPs increased over time in all groups. Conclusions By optimizing controlled sequential elevation timing, CerPP values achieved 50% of baseline within less than 2.5 minutes and >80% of baseline after 7 minutes of CPR. This novel CPR approach rapidly restored CerPPs to near normal values non-invasively and without vasopressors.

Supplemental Digital Content is available in the text., Objectives: To construct a highly detailed yet practical, attainable roadmap for enhancing the likelihood of neurologically intact survival following sudden cardiac arrest. Design, Setting, and Patients: Population-based outcomes following out-of-hospital cardiac arrest were collated for 10 U.S. counties in Alaska, California, Florida, Ohio, Minnesota, Utah, and Washington. The 10 identified emergency medical services systems were those that had recently reported significant improvements in neurologically intact survival after introducing a more comprehensive approach involving citizens, hospitals, and evolving strategies for incorporating technology-based, highly choreographed care and training. Detailed inventories of in-common elements were collated from the ten 9-1-1 agencies and assimilated. For reference, combined averaged outcomes for out-of-hospital cardiac arrest occurring January 1, 2017, to February 28, 2018, were compared with concurrent U.S. outcomes reported by the well-established Cardiac Arrest Registry to Enhance Survival. Interventions: Most commonly, interventions and components from the ten 9-1-1 systems consistently included extensive public cardiopulmonary resuscitation training, 9-1-1 system-connected smart phone applications, expedited dispatcher procedures, cardiopulmonary resuscitation quality monitoring, mechanical cardiopulmonary resuscitation, devices for enhancing negative intrathoracic pressure regulation, extracorporeal membrane oxygenation protocols, body temperature management procedures, rapid cardiac angiography, and intensive involvement of medical directors, operational and quality assurance officers, and training staff. Measurements and Main Results: Compared with Cardiac Arrest Registry to Enhance Survival (n = 78,704), the cohorts from the 10 emergency medical services agencies examined (n = 2,911) demonstrated significantly increased likelihoods of return of spontaneous circulation (mean 37.4% vs 31.5%; p < 0.001) and neurologically favorable hospital discharge, particularly after witnessed collapses involving bystander cardiopulmonary resuscitation and shockable cardiac rhythms (mean 10.7% vs 8.4%; p < 0.001; and 41.6% vs 29.2%; p < 0.001, respectively). Conclusions: The likelihood of neurologically favorable survival following out-of-hospital cardiac arrest can improve substantially in communities that conscientiously and meticulously introduce a well-sequenced, highly choreographed, system-wide portfolio of both traditional and nonconventional approaches to training, technologies, and physiologic management. The commonalities found in the analyzed systems create a compelling case that other communities can also improve out-of-hospital cardiac arrest outcomes significantly by conscientiously exploring and adopting similar bundles of system organization and care.

Objectives Resuscitation in the Head Up position improves outcomes in animals treated with active compression decompression cardiopulmonary resuscitation and an impedance threshold device (ACD + ITD CPR). We assessed impact of time to deployment of an automated Head Up position (AHUP) based bundle of care after out-of-hospital cardiac arrest on return of spontaneous circulation (ROSC). Methods Observational data were analyzed from a patient registry. Patients received treatment with 1) ACD + and/or automated CPR 2) an ITD and 3) an AHUP device. Probability of ROSC (ROSCprob) from the 9-1-1 call to AHUP device placement was assessed with a restricted cubic spline model and linear regression. Results Of 11 sites, 6 recorded the interval from 9-1-1 to AHUP device (n = 227). ROSCprob for all rhythms was 34%(77/227). Median age (range) was 66 years (19-101) and 68% men. The ROSCprob for shockable rhythms was 47%(18/38). Minutes from 9-1-1 to AHUP device (median, range) varied between sites: 1) 6.4(4,15), 2) 8.0(5,19), 3) 9.9(4, 12), 4) 14.1(6, 36), 5) 15.9(6, 34), 6) 19.0(8, 38),(p = 0.0001). ROSCprob also varied; 1) 55.1%(16/29), 2) 60%(3/5), 3) 50%(3/6), 4) 22.7%(17/75), 5) 26.4%(9/34), and 6) 37.1%(29/78), (p = 0.019). For all rhythms between 4-12 minutes (n = 85), ROSCprob declined 5.6% for every minute elapsed (p = 0.024). For shockable rhythms, between 6-15 minutes (n = 23), ROSCprob declined 9.0% for every minute elapsed (p = 0.006). Conclusions Faster time to deployment of an AHUP based bundle of care is associated with higher incidence of ROSC. This must be considered when evaluating and implementing this bundle.

Aim of the study Controlled sequential elevation of the head and thorax (CSE) during active compression decompression (ACD) cardiopulmonary resuscitation (CPR) with an impedance threshold device (ITD) has been shown to increase cerebral perfusion pressure and cerebral blood flow in previous animal studies as compared to the traditional supine position. The potential for this novel bundled treatment strategy to improve survival with intact neurological function is unknown. Methods Female farm pigs were sedated, intubated, and anesthetized. Central arterial and venous access were continuously monitored. Regional brain tissue perfusion (CerO2) was also measured transcutaneous. Ventricular fibrillation (VF) was induced and untreated for 10 min. Pigs were randomized to (1) Conventional CPR (C-CPR) flat or (2) ACD + ITD CSE CPR that included 2 min of ACD + ITD with the head and heart first elevated 10 and 8 cm, and then gradual elevation over 2 min to 22 and 9 cm, respectively. After 19 min of CPR, pigs were defibrillated and recovered. A veterinarian blinded to the intervention assessed cerebral performance category (CPC) at 24 h. A neurologically intact outcome was defined as a CPC score of 1 or 2. Categorical outcomes were analyzed by Fisher's exact test and continuous outcomes with an unpaired student's t-test. Results In 16 animals, return of spontaneous circulation rate was 8/8 (100%) with ACD + ITD CSE and 3/8 (25%) for C-CPR (p = 0.026). For the primary outcome of neurologically intact survival, 6/8 (75%) pigs had a CPC score 1 or 2 with ACD + ITD CSE versus 1/8 (12.5%) with C-CPR (p = 0.04). Coronary perfusion pressure (mmHg, mean ± SD) was higher with CSE at 18 min (41 ± 24 versus 10 ± 5, p = 0.004). rSO2 (%, mean ± SD) and ETCO2 (mmHg, mean ± SD) values were higher at 18 min with CSE (32 ± 9 versus 17 ± 2, p = 0.01, and 55 mmHg ± 10 versus 21 mmHg ± 4, p Conclusions The novel bundled resuscitation approach of CSE with ACD + ITD CPR increased favorable neurological survival versus C-CPR in a swine model of cardiac arrest.

Introduction Cerebral blood flow during cardiopulmonary resuscitation (CPR) is a major neuroprognostic factor although not clinically feasible for routine assessment and monitoring. In this context, a surrogate marker for cerebral perfusion during CPR is highly desirable. Yet, cerebral blood flow hemodynamic determinants remain poorly understood and their significance might be altered by changes in head positioning such as flat, head up, and head down during CPR. Hypothesis We hypothesized that routinely measured hemodynamic parameters would correlate with cerebral brain flow during CPR, independently of the head position. Methods Associations between cerebral blood flow, measured using microsphere techniques, and hemodynamic parameters were studied from two prior publications. Eight pigs receiving CPR with an automated device and an impedance threshold device in the flat or supine, whole body head down and whole body head up tilt positions were analysed for the derivation sample. Relevant associations were examined for consistency in an external validation sample consisting of 18 pigs randomized to supine position versus head and torso elevation. Results After adjusting for position, arterial blood pressure and cerebral perfusion pressure during decompression were significantly associated with cerebral blood flow, in the derivation and the external validation samples. No significant associations were found between cerebral blood flow during CPR and right atrial pressure, intracranial pressure, end tidal CO2, carotid blood flow, and coronary perfusion pressure in the derivation sample. Conclusion Decompression arterial blood pressure and cerebral perfusion pressure are relevant candidate surrogate markers for cerebral blood flow during CPR, independently of head position.

Introduction: Controlled sequential elevation of the head and thorax (CSE) during active compression-decompression (ACD) CPR with an impedance threshold device (ITD) has previously resulted in sustained nearly normal cerebral perfusion pressures (CerPP) of 75 mmHg. However, the optimal speed of CSE remains unknown. It is also unknown if some CPR is needed to ‘prime the system’ prior to maximal CSE. Hypothesis: An optimized CSE will achieve 50% of baseline (50% BL) CerPP in Methods: Female farm pigs were intubated and anesthetized. Central vascular and intracranial access were obtained. After 8 min of untreated ventricular fibrillation, pigs were placed in a customized elevation device (CED). After 2 min of ACD+ITD CPR at the lowest CED level to prime the circulation, pigs were randomized to CSE over 1) 4-min or 2) 10-min until the CED reached its highest level. ACD ITD CPR was performed for a total of 19 minutes. Based upon initial results, two additional groups of pigs were studied: one with a CSE over 2-min after the 2 min ‘priming’ step, and the other with CSE over 24-sec without priming. The primary outcome was time in minutes to achieve 50% BL of CerPP values. Results: There were six pigs per study group (4-min, 10-min, 2-min and 24-sec). The 4-min CSE group achieved 50% BL CerPP faster (min ± SD) than the 10-min CSE group (2.53 ± 1.26 vs 5.98 ± 3.16 , p=0.04, Figure 1). The 2-min CSE group CerPP was similar to the 4-min group (2.36 ± 2.18, p=0.92). The time to 50% BL CerPP trended 4 min faster in the 2-min CSE group versus the 24-sec CSE group (6.6 ± 6.73, p=0.16), as shown in the figure. With CSE, CerPPs increased over time in all groups. All pigs were resuscitated. Conclusions: A 50% BL CerPP value was achieved in

Aim of the study Negative intrathoracic pressure (ITP) during the decompression phase of cardiopulmonary resuscitation (CPR) is essential to refill the heart, increase cardiac output, maintain cerebral and coronary perfusion pressures, and improve survival. In order to generate negative ITP, an airway seal is necessary. We tested the hypothesis that some supraglottic airway (SGA) devices do not seal the airway as well the standard endotracheal tube (ETT). Methods Airway pressures (AP) were measured as a surrogate for ITP in seven recently deceased human cadavers of varying body habitus. Conventional manual, automated, and active compression-decompression CPR were performed with and without an impedance threshold device (ITD) in supine and Head Up positions. Positive pressure ventilation was delivered by an ETT and 5 SGA devices tested in a randomized order in this prospective cross-over designed study. The primary outcome was comparisons of decompression AP between all groups. Results An ITD was required to generate significantly lower negative ITP during the decompression phase of all methods of CPR. SGAs varied in their ability to support negative ITP. Conclusion In a human cadaver model, the ability to generate negative intrathoracic pressures varied with different SGAs and an ITD regardless of the body position or CPR method. Differences in SGAs devices should be strongly considered when trying to optimize cardiac arrest outcomes, as some SGAs do not consistently develop a seal or negative intrathoracic pressure with multiple different CPR methods and devices.

Aim of the Study Elevation of the head and thorax (HUP) during cardiopulmonary resuscitation (CPR) has been shown to double brain blood flow with increased cerebral perfusion pressures (CerPP) after active compression-decompression (ACD) CPR with an impedance threshold device (ITD). However, the optimal angle for HUP CPR is unknown. Methods In Study A, different angles were assessed (20°, 30°, 40°), each randomized over 5-min periods of ACD + ITD CPR, after 8 min of untreated ventricular fibrillation in an anesthetized swine model. Based upon Study A, Study B was performed, where animals were randomized to 1 of 2 sequences: 20°, 30°, 40° or 40°, 30°, 20° with a similar protocol. The primary endpoint was CerPP for both studies. Results In Study A, no optimal HUP angle was observed in 18 pigs. CerPPs for 30° and 40° (mmHg, mean ± SD) were equivalent (44 ± 22 and 47 ± 26, p = 0.18). However, CerPP appeared higher when 40° HUP was performed during the last 5-min of CPR, suggestive of a sequence effect. For Study B, after 17 min of CPR, CerPP (mmHg) were higher with the 20°, 30°, 40° sequence: 60 ± 17 versus 33 ± 18 (p = 0.035). Conclusions No optimal HUP CPR angle was observed. However, controlled progressive elevation of the head and thorax during CPR is more beneficial than an absolute angle or height to maximize CerPP. Further studies are needed to determine the optimal rate of rise during HUP ACD + ITD CPR. Institutional Protocol Number 17-06.

Background: Elevation of the head and thorax (HUP) during cardiopulmonary resuscitation (CPR) has been shown to result in a doubling of brain blood flow with higher Cerebral Perfusion Pressures (CerPP) after prolonged active compression-decompression (ACD) CPR with an impedance threshold device (ITD). However, the optimal angle and speed of elevation are unknown. Methods: In study A, in an anesthetized female 40 kg pig model of untreated ventricular fibrillation for 8 min, different HUP angles were assessed (20°, 30°, 40°) in a randomized manner each over a 5-minute periods of ACD+ITD CPR. Based upon study A results, study B was performed, wherein animals were randomized to the two following sequences: 20°, 30°, 40° or 40°, 30°, 20° using the same protocol. The primary endpoint was mean ± SD CerPP (mmHg) for both studies. Results: In study A, 18 pigs were studied. Overall, there was no optimal HUP angle: CerPP was 36 ± 19 for 20°, 42 ± 21 for 30°, and 44 ± 27 for 40° (p = 0.57). However, CerPPs were higher if 40 o HUP was performed during the last 5 minutes of the resuscitation (77 ± 17), versus 20 o HUP and 30 o HUP (44± 18, p = 0.003), suggestive of a sequence effect. To test this hypothesis, study B then enrolled additional animals to compare two elevation sequences 20°, 30°, 40° (n = 6) or 40°, 30°, 20° (n = 5). At 15 min of CPR, the CerPP for 20°, 30°, 40° group was 60 ± 17 and for 40°, 30°, 20° the CerPP was 23 ± 19 (p = 0.01). CerPPs were higher for the 20°, 30°, 40° group throughout the resuscitation (Figure 1). Coronary perfusion pressure was also significantly higher in the 20°, 30°, 40° group (50 ± 17 mmHg versus 22 ± 16 mmHg, p = 0.036) Conclusions: There did not appear to be an optimal HUP angle during ACD+ITD CPR. By contrast, there was an optimal HUP sequence (20,30,40) that resulted in significantly higher CerPP, suggesting controlled progressive elevation is important when performing HUP CPR as compared to an absolute immediate elevation of the head and thorax.