Racial disparities in outcomes following PEA and asystole in-hospital cardiac arrests

AimTo define the racial differences present after PEA and asystolic IHCA and explore factors that could contribute to this disparity.MethodsWe analyzed PEA and asystolic IHCA in the Get-With-The-Guidelines-Resuscitation database. Multilevel conditional fixed effects logistic regression models were used to estimate the relationship between race and survival to discharge and return of spontaneous circulation (ROSC), sequentially controlling for hospital, patient demographics, comorbidities, arrest characteristic, process measures, and interventions in place at time of arrest.ResultsAmong the 561 hospitals, there were 76,835 patients who experienced IHCA with an initial rhythm of PEA or asystole (74.8% white, 25.2% black). Unadjusted ROSC rate was 55.1% for white patients and 54.1% for black patients (unadjusted OR: 0.94 [95% CI, 0.90–0.98], p = 0.016). Survival to discharge was 12.8% for white patients and 10.4% for black patients (unadjusted OR: 0.83 [95% CI, 0.78–0.87], p < 0.001). After adjusting for temporal trends, patient characteristics, hospital, and arrest characteristics, there remained a difference in survival to discharge (OR: 0.85 [95% CI, 0.79–0.92]) and rate of ROSC (OR: 0.88 [95% CI, 0.84–0.92]). Black patients had a worse mental status at discharge after survival. Rates of DNAR placed after survival from were lower in black patients with a rate of 38.3% compared to 44.5% in white patients (p < 0.001).ConclusionBlack patients are less likely to experience ROSC and survival to discharge after PEA or asystole IHCA. Individual patient characteristics, event characteristics, and hospital characteristics don’t fully explain this disparity. It is possible that disease burden and end-of-life preferences contribute to the racial disparity.     

Computed tomography findings of complications resulting from cardiopulmonary resuscitation

IntroductionThis retrospective study was conducted to evaluate injuries related to cardiopulmonary resuscitation (CPR) and their associated factors using postmortem computed tomography (PMCT) and whole body CT after successful resuscitation.MethodsThe inclusion criteria were adult, non-traumatic, out-of-hospital cardiac arrest patients who were transported to our emergency room between April 1, 2008 and March 31, 2013. Following CPR, PMCT was performed in patients who died without return of spontaneous circulation (ROSC). Similarly, CT scans were performed in patients who were successfully resuscitated within 72 h after ROSC. The injuries associated with CPR were analysed retrospectively on CT images.ResultsDuring the study period, 309 patients who suffered out-of hospital cardiac arrest were transported to our emergency room and received CPR; 223 were enrolled in the study.The CT images showed that 156 patients (70.0%) had rib fractures, and 18 patients (8.1%) had sternal fractures. Rib fractures were associated with older age (78.0 years vs. 66.0 years, p < 0.01), longer duration of CPR (41 min vs. 33 min, p < 0.01), and lower rate of ROSC (26.3% vs. 55.3%, p < 0.01). All sternal fractures occurred with rib fractures and were associated with a greater number of rib fractures, higher age, and a lower rate of ROSC than rib fractures only cases. Bilateral pneumothorax was observed in two patients with rib fractures.ConclusionsPMCT is useful for evaluating complications related to chest compression. Further investigations with PMCT are needed to reduce complications and improve the quality of CPR.     

Oxygen requirement during cardiopulmonary resuscitation (CPR) to effect return of spontaneous circulation

BackgroundRecent scientific evidence has demonstrated the importance of good quality chest compressions without interruption to improve cardiac arrest resuscitation rates, and suggested that a de-emphasis on minute ventilation is needed. However, independent of ventilation, the role of oxygen and the optimal oxygen concentration during CPR is not known. Previous studies have shown that ventilation with high oxygen concentration after CPR is associated with worse neurologic outcome. We tested the hypothesis that initial ventilation during CPR without oxygen improves resuscitation success.MethodsSprague–Dawley rats were anesthetized with ketamine/xylazine (IP), intubated and ventilated with room air. A KCl bolus (0.04 mg/g) was given (IV) to induce asystolic cardiac arrest and ventilation was stopped. At 6 min, CPR was started with an automated chest compressor at a rate of 200–240/min and epinephrine (0.01 mg/kg) was given 1 min later. During CPR, the ventilation rate was 50% of baseline with one of three oxygen concentrations: (1) 0% O₂ (100% N₂), (2) 21% O₂, or (3) 100% O₂. The prescribed oxygen concentration was continued for 2 min after return of spontaneous circulation (ROSC) and then all animals were switched to 100% oxygen for 1 h prior to extubation. Blood gases were measured at baseline, 2 min and 1 h after ROSC. Group comparisons were done using Fisher's exact test and ANOVA.ResultsROSC was achieved in 1/10 (0% O₂), 9/11 (21% O₂) and 10/12 (100% O₂, p < 0.001). ROSC times after starting CPR were 80 s in the 0% O₂, 115 ± 87 s in the 21% O₂ group and 95 ± 33 s in the 100% O₂ group (mean ± SD, p = 0.5). Aortic end-diastolic pressure before ROSC was not different among groups. 100% oxygen ventilation in the first 2 min resulted in higher PaO₂ at ROSC 2 min (109 ± 44 mm Hg vs. 33 ± 8 mm Hg, p < 0.001). Survival to 72 h was 0/1 (0% O₂), 7/9 (21% O₂) and 8/10 (100% O₂) with a low neurologic deficit score in both O₂ groups (NDS range 5–25).ConclusionsIn a mild cardiac arrest model with generally good neurologic recovery, initial CPR ventilation with no O₂ did not allow for ROSC. In contrast, CPR coupled with room air or higher oxygen levels result in a high rate of ROSC with good neurologic recovery. During CPR, the level of oxygenation must be considered, which if too low may preclude initial ROSC.     

Cardiopulmonary resuscitation quality and patient survival outcome in cardiac arrest: A systematic review and meta-analysis

AimTo conduct a systematic review and meta-analysis to determine whether cardiopulmonary resuscitation (CPR) quality, as indicated by parameters such as chest compression depth, compression rate and compression fraction, is associated with patient survival from cardiac arrest.MethodsFive databases were searched (MEDLINE, Embase, CINAHL, Scopus and Cochrane) as well as the grey literature (MedNar). To satisfy inclusion criteria, studies had to document human cases of in- or out-of hospital cardiac arrest where CPR quality had been recorded using an automated device and linked to patient survival. Where indicated (I² < 75%), meta-analysis was undertaken to examine the relationship between individual CPR quality parameters and either survival to hospital discharge (STHD) or return of spontaneous circulation (ROSC).ResultsDatabase searching yielded 8,842 unique citations, resulting in the inclusion of 22 relevant articles. Thirteen were included in the meta-analysis. Chest compression depth was significantly associated with STHD (mean difference (MD) between survivors and non-survivors 2.59 mm, 95% CI: 0.71, 4.47); and with ROSC (MD 0.99 mm, 95% CI: 0.04, 1.93). Within the range of approximately 100–120 compressions per minute (cpm), compression rate was significantly associated with STHD; survivors demonstrated a lower mean compression rate than non-survivors (MD −1.17 cpm, 95% CI: −2.21, −0.14). Compression fraction could not be examined by meta-analysis due to high heterogeneity, however a higher fraction appeared to be associated with survival in cases with a shockable initial rhythm.ConclusionsChest compression depth and rate were associated with survival outcomes. More studies with consistent reporting of data are required for other quality parameters.     

Outcome of out-of-hospital cardiac arrest over a period of 15 years in comparison to the RACA score in a physician staffed urban emergency medical service in Germany

BackgroundPatient outcome after out of hospital cardiac arrest (OHCA) depends on the cardiopulmonary resuscitation (CPR) performance and might also be influenced by organisation of the emergency medical service (EMS) and implementation of guidelines.AimTo assess the rate of return of spontaneous circulation (ROSC) after cardiac arrest to the predicted rate by the ROSC after cardiac arrest (RACA) score over a 15-year period reflecting three different implemented ALS-guidelines in a physician-staffed EMS.MethodsAll adult patients with non-traumatic OHCA in the EMS of Bonn from 1996 to 2011 were included. Utstein data from three 5-years time periods (1996–2001, 2001–2006, 2006–2011) representing different ALS-guideline implementations were collected. Group comparisons were made in terms of incidence, epidemiology and short-term outcome of CPR with emphasis on changes over time and factors of importance. In each group observed ROSC rate were compared to the predicted ROSC rates (the RACA score).ResultsCPR by the ALS unit was attempted in a total of 1989 patients (735, 666, and 588 patients in the first, second and third period, respectively). Average crude incidence of CPR per 100,000 person-years decreased over time (61.3; 55.5; 49.0/100,000/years) while patients treated were significantly older (65.5 ± 16.5; 67.9 ± 15; 68.9 ± 15.7 (p < 0.001)). Observed ROSC rates were higher than predicted by the RACA score in all time periods, however, admittance to ICU decreased significantly from 50% in the first five-year period to 38% last five-year period (p < 0.001). From first to third period the proportion of arrests with first observed rhythm of VT/VF arrests did not change (29% vs. 27%, p = 0.323) nor there were changes in bystander CPR rates (17% vs. 17%, p = 0.520).ConclusionsIn a 15-years period and in the setting of a physician-staffed EMS the ROSC rates remain higher than predicted by the RACA score but the admittance to the ICU after OHCA declined significantly. This finding was accompanied by a decrease in CPR incidence and an increase in age of patients.     

Outcome of avalanche victims with out-of-hospital cardiac arrest

Study backgroundPrevious studies focused on the outcome of avalanche victims with out-of-hospital cardiac arrest (OHCA) after long duration of burial (>35 min); the outcome of victims with short duration (≤35 min) remains obscure.Aim of the studyTo investigate outcome of avalanche victims with OHCA.MethodsRetrospective analysis of avalanche victims with OHCA between 2008 and 2013 in the Tyrolean Alps.Results55 avalanche victims were identified, 32 of whom were declared dead after extrication without cardiopulmonary resuscitation (CPR), all with long duration of burial. In the remaining 23 CPR was initiated at scene; three were partially and 20 completely buried, nine of whom suffered short and 11 long duration of burial. All nine victims with short duration of burial underwent restoration of spontaneous circulation (ROSC) at scene, four of them after bystander CPR, five after advanced life support by the emergency physician. Two patients with ROSC after short duration of burial and bystander CPR survived to hospital discharge with cerebral performance category 1. None of the 11 victims with long duration of burial survived to hospital discharge, although six were transported to hospital with ongoing CPR and three were supported with extracorporeal circulation.ConclusionsIn this case series survival with favourable neurological outcome was observed in avalanche victims with short duration of burial only if bystander CPR was immediately performed and ROSC achieved. Strategies for reducing avalanche mortality should focus on prompt extrication from the snow and immediate bystander CPR by uninjured companions.     

Bundled postconditioning therapies improve hemodynamics and neurologic recovery after 17 min of untreated cardiac arrest

ObjectiveIschemic postconditioning (stutter CPR) and sevoflurane have been shown to mitigate the effects of reperfusion injury in cardiac tissue after 15 min of ventricular fibrillation (VF) cardiac arrest. Poloxamer 188 (P188) has also proven beneficial to neuronal and cardiac tissue during reperfusion injury in human and animal models. We hypothesized that the use of stutter CPR, sevoflurane, and P188 combined with standard advanced life support would improve post-resuscitation cardiac and neurologic function after prolonged VF arrest.MethodsFollowing 17 min of untreated VF, 20 pigs were randomized to Control treatment with active compression/decompression (ACD) CPR and impedance threshold device (ITD) (n = 8) or Bundle therapy with stutter ACD CPR + ITD + sevoflurane + P188 (n = 12). Epinephrine and post-resuscitation hypothermia were given in both groups per standard protocol. Animals that achieved return of spontaneous circulation (ROSC) were evaluated with echocardiography, biomarkers, and a blinded neurologic assessment with a cerebral performance category score.ResultsBundle therapy improved hemodynamics during resuscitation, reduced need for epinephrine and repeated defibrillation, reduced biomarkers of cardiac injury and end-organ dysfunction, and increased left ventricular ejection fraction compared to Controls. Bundle therapy also improved rates of ROSC (100% vs. 50%), freedom from major adverse events (50% vs. 0% at 48 h), and neurologic function (42% with mild or no neurologic deficit and 17% achieving normal function at 48 h).ConclusionsBundle therapy with a combination of stutter ACD CPR, ITD, sevoflurane, and P188 improved cardiac and neurologic function after 17 min of untreated cardiac arrest in pigs.All studies were performed with approval from the Institutional Animal Care Committee of the Minneapolis Medical Research Foundation (protocol #12-11).     

Association between early arterial blood gas tensions and neurological outcome in adult patients following in-hospital cardiac arrest

ObjectiveThe early partial pressures of arterial O₂ (PaO₂) and CO₂ (PaCO₂) have been found in animal studies to be correlated with neurological outcome after brain injury. However, the relationship of early PaO₂ and PaCO₂ to the neurological outcomes of resuscitated patients after cardiac arrest was still not clear.MethodsThis was a retrospective observational cohort study in a single medical center. Adult patients who had in-hospital cardiac arrest between 2006 and 2012 and achieved sustained return of spontaneous circulation (ROSC) (ROSC > 20 min without resumption of chest compression) were included. Multivariable logistic regression analysis was used to identify factors associated with favorable neurological outcome at hospital discharge. The first PaO₂ and PaCO₂ values measured after first sustained ROSC were used for analysis.ResultsOf the 550 included patients, 154 (28%) survived to hospital discharge and 74 (13.5%) achieved favorable neurological outcome. The mean time from sustained ROSC to the measurement of PaO₂ and PaCO₂ was 136.8 min. The mean PaO₂ and PaCO₂ were 167.4 mmHg and 40.3 mmHg, respectively. PaO₂ between 70 and 240 mmHg (odds ratio [OR] 1.96, 95% confidence interval [CI] 1.08–3.64) and PaCO₂ levels (OR 0.98, 95% CI 0.95–0.99) were positively and inversely associated with favorable neurological outcome, respectively.ConclusionsThe early PaO₂ and PaCO₂ levels obtained after ROSC might be correlated with neurological outcome of patients with in-hospital cardiac arrest. However, because of the inherent limitations of the retrospective design, these results should be further validated in future studies.     

The duration of cardiopulmonary resuscitation in emergency departments after out-of-hospital cardiac arrest is associated with the outcome: A nationwide observational study

Aim of the studyThe appropriate duration of cardiopulmonary resuscitation (CPR) for patients who experience out-of-hospital cardiac arrest (OHCA) remains unknown. This study aimed to evaluate the duration of CPR in emergency departments (EDs) and to determine whether the institutions’ median duration of CPR was associated with survival-to-discharge rate.MethodsA cohort of adult patients from a nationwide OHCA registry was retrospectively evaluated. The main variable was the median duration of CPR for each ED (institutional duration), and the main outcome was survival to discharge. Multivariable logistic regression analysis was performed to adjust for individual and aggregated confounders.ResultsAmong the 107,736 patients who experienced OHCA between 2006 and 2010, 30,716 (28.5%) were selected for analysis. The median age was 65 years, and 67.1% were men. The median duration of CPR for all EDs was 28 min, ranging from 11 to 45 min. EDs were categorized into 3 groups according to their institutional duration of CPR: groups A (<20 min), B (20–29 min), C (≥30 min). The observed survival rates of the 3 groups were 2.11%, 5.20%, and 5.62%, respectively. Compared with group B, the adjusted difference (95% confidence interval) for survival to discharge was 3.01% (1.90–4.11, P < 0.001) for group A, and 0.33% (−0.64 to 1.30, P = 0.51) for group C.ConclusionThe duration of CPR varied widely among hospitals. The institutional duration of CPR less than 20 min was significantly associated with lower survival-to-discharge rate.     

Quantitative relationship between end-tidal carbon dioxide and CPR quality during both in-hospital and out-of-hospital cardiac arrest

ObjectiveCardiopulmonary resuscitation (CPR) guidelines recommend the administration of chest compressions (CC) at a standardized rate and depth without guidance from patient physiologic output. The relationship between CC performance and actual CPR-generated blood flow is poorly understood, limiting the ability to define “optimal” CPR delivery. End-tidal carbon dioxide (ETCO₂) has been proposed as a surrogate measure of blood flow during CPR, and has been suggested as a tool to guide CPR despite a paucity of clinical data. We sought to quantify the relationship between ETCO₂ and CPR characteristics during clinical resuscitation care.MethodsMulticenter cohort study of 583 in- and out-of-hospital cardiac arrests with time-synchronized ETCO₂ and CPR performance data captured between 4/2006 and 5/2013. ETCO₂, ventilation rate, CC rate and depth were averaged over 15-s epochs. A total of 29,028 epochs were processed for analysis using mixed-effects regression techniques.ResultsCC depth was a significant predictor of increased ETCO₂. For every 10 mm increase in depth, ETCO₂ was elevated by 1.4 mmHg (p < .001). For every 10 breaths/min increase in ventilation rate, ETCO₂ was lowered by 3.0 mmHg (p < .001). CC rate was not a predictor of ETCO₂ over the dynamic range of actual CC delivery. Case-averaged ETCO₂ values in patients with return of spontaneous circulation were higher compared to those who did not have a pulse restored (34.5 ± 4.5 vs 23.1 ± 12.9 mmHg, p < .001).ConclusionsETCO₂ values generated during CPR were statistically associated with CC depth and ventilation rate. Further studies are needed to assess ETCO₂ as a potential tool to guide care.     

Simultaneous beat-to-beat assessment of arterial blood pressure and quality of cardiopulmonary resuscitation in out-of-hospital and in-hospital settings

ObjectiveThe current recommendation for depth and rate of chest compression (CC) during cardiopulmonary resuscitation (CPR) is based on limited hemodynamic data recorded during human CPR. We have evaluated the possible association between CC depth and rate and continuously measured arterial blood pressure during adult CPR.MethodsThis prospective study included data from 104 patients resuscitated inside or outside hospital. Adequate data on continuously measured invasive arterial blood pressure (BP) and the quality of CPR from a defibrillator capable recording CPR quality parameters was successful in 39 patients. We used logistic regression and mixed effects modeling to identify CC depths and rates associated with systolic blood pressure (SBP) ≥85 mmHg and diastolic blood pressure (DBP) ≥30 mmHg.ResultsWe analyzed 41,575 compression-BP pairs. The values for blood pressure varied greatly between the patients. SBP varied from 25 to 225 mmHg and DBP from 2 to 59 mmHg. CC rate 100–120/min and CC depth ≥60 mm (without mattress deflection correction) was associated with DBP ≥30 mmHg in both femoral (OR 1.14; 95% CI 1.03, 1.26; p < 0.05) and radial (OR 4.70; 95% CI 3.92, 5.63; p < 0.001) recordings. For any given subject there was a weak upward trend in blood pressure as CC depth increased.ConclusionDeeper CC does not equal higher BP in every patient. The heterogeneity of patients creates a challenge to find the optimal way to resuscitate patients individually.Clinical Trial Registration: Clinicaltrials.gov NCT00951704.     

Cerebral oximetry and return of spontaneous circulation after cardiac arrest: A systematic review and meta-analysis

AimThe prediction of return of spontaneous circulation (ROSC) during resuscitation of patients suffering of cardiac arrest (CA) is particularly challenging. Regional cerebral oxygen saturation (rSO₂) monitoring through near-infrared spectrometry is feasible during CA and could provide guidance during resuscitation.MethodsWe conducted a systematic review and meta-analysis on the value of rSO₂ in predicting ROSC both after in-hospital (IH) or out-of-hospital (OH) CA. Our search included MEDLINE (PubMed) and EMBASE, from inception until April 4th, 2015. We included studies reporting values of rSO₂ at the beginning of and/or during resuscitation, according to the achievement of ROSC.ResultsA total of nine studies with 315 patients (119 achieving ROSC, 37.7%) were included in the meta-analysis. The majority of those patients had an OHCA (n = 225, 71.5%; IHCA: n = 90, 28.5%). There was a significant association between higher values of rSO₂ and ROSC, both in the overall calculation (standardized mean difference, SMD –1.03; 95%CI –1.39,–0.67; p < 0.001), and in the subgroups analyses (rSO₂ at the beginning of resuscitation: SMD –0.79; 95%CI –1.29,–0.30; p = 0.002; averaged rSO₂ value during resuscitation: SMD –1.28; 95%CI –1.74,–0.83; p < 0.001).ConclusionsHigher initial and average regional cerebral oxygen saturation values are both associated with greater chances of achieving ROSC in patients suffering of CA. A note of caution should be made in interpreting these results due to the small number of patients and the heterogeneity in study design: larger studies are needed to clinically validate cut-offs for guiding cardiopulmonary resuscitation.     

Two minutes CPR versus five cycles CPR prior to reanalysis of the cardiac rhythm: A prospective,randomized simulator-based trial

Aim of the studyWhile the 2005 cardiopulmonary resuscitation (CPR) guidelines recommended to provide CPR for five cycles before the next cardiac rhythm check, the current 2010 guideline now recommend to provide CPR for 2 min. Our aim was to compare adherence to both targets in a simulator-based randomized trial.Methods119 teams, consisting of three to four physicians each, were randomized to receive a graphical display of the simplified circular adult BLS algorithm with the instruction to perform CPR for either 2 min or five cycles 30:2. Subsequently teams had to treat a simulated unwitnessed cardiac arrest. Data analysis was performed using video-recordings obtained during simulations. The primary endpoint was adherence, defined as being within ±20% of the instructed target (i.e. 96–144 s in the 2 min teams and 4–6 cycles in the fivex30:2 teams).Results22/62 (35%) of the “two minutes” teams and 48/57 (84%) of the “five × 30:2″ teams provided CPR within a range of ± 20% of their instructed target (P < 0.0001). The median time of CPR prior to rhythm check was 91 s and 87 s, respectively, (P = 0.59) with a significant larger variance (P = 0.023) in the “two minutes” group.ConclusionsThis randomized simulator-based trial found better adherence and less variance to an instruction to continue CPR for five cycles before the next cardiac rhythm check compared to continuing CPR for 2 min. Avoiding temporal targets whenever possible in guidelines relating to stressful events appears advisable.     

The association between chest compression release velocity and outcomes from out-of-hospital cardiac arrest

BackgroundPrevious studies have demonstrated significant relationships between cardiopulmonary resuscitation (CPR) quality metrics and survival to hospital discharge from out-of-hospital cardiac arrest (OHCA). Recently, it has been suggested that a new metric, chest compression release velocity (CCRV), may be associated with improved survival from OHCA.Methods and resultsWe performed a retrospective review of all treated adult OHCA occurring over a two year period beginning January 1, 2012. CPR metrics were abstracted from accelerometer measurements during each resuscitation. Multivariable regression analysis was used to examine the impact of CCRV on survival to hospital discharge. Secondary outcome measures were the impact of CCRV on return of spontaneous circulation (ROSC) and neurologically intact survival (MRS ≤ 3). Among 1800 treated OHCA, 1137 met inclusion criteria. The median (IQR) age was 71.6 (60.6, 82.3) with 724 (64%) being male. The median (IQR) CCRV (mm/s) amongst 96 survivors was 334.5 (300.0, 383.2) compared to 304.0 (262.6, 354.1) in 1041 non survivors (p < 0.001). When adjusted for Utstein variables, the odds of survival to hospital discharge for each 10 mm/s increase in CCRV was 1.02 (95% CI: 0.98, 1.06). Similarly the odds of ROSC and neurologically intact survival were 1.01 (95% CI: 0.99, 1.03) and 1.02 (95% CI: 0.98, 1.06), respectively.ConclusionsWhen adjusted for Utstein variables, CCRV was not significantly associated with outcomes from OHCA. Further research in other EMS systems is required to clarify the potential impact of this variable on OHCA survival.     

Intra-arrest hypothermia: Both cold liquid ventilation with perfluorocarbons and cold intravenous saline rapidly achieve hypothermia,but only cold liquid ventilation improves resumption of spontaneous circulation

BackgroundRapid intra-arrest induction of hypothermia using total liquid ventilation (TLV) with cold perfluorocarbons improves resuscitation outcome from ventricular fibrillation (VF). Cold saline intravenous infusion during cardiopulmonary resuscitation (CPR) is a simpler method of inducing hypothermia. We compared these 2 methods of rapid hypothermia induction for cardiac resuscitation.MethodsThree groups of swine were studied: cold preoxygenated TLV (TLV, n = 8), cold intravenous saline infusion (S, n = 8), and control (C, n = 8). VF was electrically induced. Beginning at 8 min of VF, TLV and S animals received 3 min of cold TLV or rapid cold saline infusion. After 11 min of VF, all groups received standard air ventilation and closed chest massage. Defibrillation was attempted after 3 min of CPR (14 min of VF). The end point was resumption of spontaneous circulation (ROSC).ResultsPulmonary arterial (PA) temperature decreased after 1 min of CPR from 37.2 °C to 32.2 °C in S and from 37.1 °C to 34.8 °C in TLV (S or TLV vs. C p < 0.0001). Coronary perfusion pressure (CPP) was higher in TLV than S animals during the initial 3 min of CPR. Arterial pO₂ was higher in the preoxygenated TLV animals. ROSC was achieved in 7 of 8 TLV, 2 of 8 S, and 1 of 8 C (TLV vs. C, p = 0.03).ConclusionsModerate hypothermia was achieved rapidly during VF and CPR using both cold saline infusion and cold TLV, but ROSC was higher than control only in cold TLV animals, probably due to better CPP and pO₂. The method by which hypothermia is achieved influences ROSC.     

The need to resume chest compressions immediately after defibrillation attempts: An analysis of post-shock rhythms and duration of pulselessness following out-of-hospital cardiac arrest

AimCurrent consensus guidelines for cardiopulmonary resuscitation (CPR) recommend that chest compressions resume immediately after defibrillation attempts and that rhythm and pulse checks be deferred until completion of 5 compression:ventilation cycles or minimally for 2 min. However, data specifically confirming the post-shock duration of asystole or pulseless electrical activity before return of spontaneous circulation (ROSC) are lacking. Our aim was to describe the frequency of the various post-shock cardiac rhythms and the duration of post-shock pulselessness in out-of-hospital non-traumatic cardiac arrest.MethodUsing prospectively-collected data from the Resuscitation Outcomes Consortium (ROC) Epistry database, the investigators reviewed monitor-defibrillator recordings of 176 patients who received defibrillation attempts in the out-of-hospital setting for ventricular fibrillation (VF) or ventricular tachycardia (VT) with absent pulses,.ResultsAmong 376 different defibrillation attempts delivered in the 176 patients, there were 182 resulting episodes of post-shock asystole. The mean interval of asystole after defibrillation was 69 ± 136 s (median 20 s; IQR 36) and the mean interval for return of an organized rhythm was 64 ± 157 s (median 7 s; IQR 26). The mean time to ROSC was 280 ± 320 s (median 136 s; IQR 445).ConclusionAfter defibrillation attempts, the majority of patients remain pulseless for over 2 min and the duration of asystole before return of pulses is longer than 120 s beyond the shock gap in as many as 25%. These data support the recommendation to immediately resume chest compressions for 2 min following attempted defibrillation.     

Video laryngoscopy versus direct laryngoscopy for tracheal intubation during in-hospital cardiopulmonary resuscitation

AimTracheal intubation during cardiopulmonary resuscitation (CPR) is a high-risk procedure. Here, we investigated the efficacy of video laryngoscopy for tracheal intubation during CPR.MethodsData regarding tracheal intubation during CPR from in-hospital cardiac arrests occurring between January 2011 and December 2013 (n = 229) were prospectively collected and retrospectively analyzed.ResultsThe initial laryngoscopy method was video laryngoscopy in 121 patients (52.8%) and direct laryngoscopy in 108 patients (47.2%). The rate of successful intubation at the first attempt was higher with video laryngoscopy (71.9%; 87/121) than with direct laryngoscopy (52.8%; 57/108; p = 0.003). The rate of success at the first attempt was higher for experienced (73.0%; 84/115) than inexperienced operators, including residents (52.6%; 60/114; p = 0.001). Mortality at day 28 after CPR was not significantly different between patients with successful tracheal intubation at the first attempt and without (68.1% [98/144] vs. 67.1% [57/85]; p = 0.876). In multivariate logistic regression analysis, a predicted difficult airway (odds ratio [95% confidence interval] = 0.22 [0.10–0.49]; p < 0.001), intubation by an experienced operator (2.63 [1.42–4.87]; p = 0.002), and use of video laryngoscopy rather than direct laryngoscopy (2.42 [1.30–4.45]; p = 0.005) were independently associated with a successful tracheal intubation at the first attempt.ConclusionUse of video laryngoscopy during CPR from in-hospital cardiac arrest is independently associated with successful tracheal intubation at the first attempt.     

Dynamic effects of adrenaline (epinephrine) in out-of-hospital cardiac arrest with initial pulseless electrical activity (PEA)

BackgroundIn cardiac arrest, pulseless electrical activity (PEA) is a challenging clinical syndrome. In a randomized study comparing intravenous (i.v.) access and drugs versus no i.v. access or drugs during advanced life support (ALS), adrenaline (epinephrine) improved return of spontaneous circulation (ROSC) in patients with PEA. Originating from this study, we investigated the time-dependent effects of adrenaline on clinical state transitions in patients with initial PEA, using a non-parametric multi-state statistical model.Methods and resultsPatients with available defibrillator recordings were included, of whom 101 received adrenaline and 73 did not. There were significantly more state transitions in the adrenaline group than in the no-adrenaline group (rate ratio = 1.6, p < 0.001). Adrenaline markedly increased the rate of transition from PEA to ROSC during ALS and slowed the rate of being declared dead; e.g. by 20 min 20% of patients in the adrenaline group had been declared dead and 25% had obtained ROSC, whereas 50% in the no-adrenaline group have been declared dead and 15% had obtained ROSC. The differential effect of adrenaline could be seen after approx. 10 min of ALS for most transitions. For both groups the probability of deteriorating from PEA to asystole was highest during the first 15 min. Adrenaline increased the rate of transition from PEA to ventricular fibrillation or -tachycardia (VF/VT), and from ROSC to VF/VT.ConclusionsAdrenaline has notable clinical effects during ALS in patients with initial PEA. The drug extends the time window for ROSC to develop, but also renders the patient more unstable. Further research should investigate the optimal dose, timing and mode of adrenaline administration during ALS.     

An investigation of thrust,depth and the impedance cardiogram as measures of cardiopulmonary resuscitation efficacy in a porcine model of cardiac arrest

ObjectiveOptimising the depth and rate of applied chest compressions following out of hospital cardiac arrest is crucial in maintaining end organ perfusion and improving survival. The impedance cardiogram (ICG) measured via defibrillator pads produces a characteristic waveform during chest compressions with the potential to provide feedback on cardiopulmonary resuscitation (CPR) and enhance performance. The objective of this pre-clinical study was to investigate the relationship between mechanical and physiological markers of CPR efficacy in a porcine model and examine the strength of correlation between the ICG amplitude, compression depth and end-tidal CO₂ (ETCO₂).MethodsTwo experiments were performed using 24 swine (12 per experiment). For experiment 1, ventricular fibrillation (VF) was induced and mechanical CPR commenced at varying thrusts (0–60 kg) for 2 min intervals. Chest compression depth was recorded using a Philips QCPR device with additional recording of invasive physiological parameters: systolic blood pressure, ETCO2, cardiac output and carotid flow. For experiment 2, VF was induced and mechanical CPR commenced at varying depths (0–5 cm) for 2 min intervals. The ICG was recorded via defibrillator pads attached to the animal's sternum and connected to a Heartsine 500P defibrillator. ICG amplitude, chest compression depth, systolic blood pressure and ETCO₂ were recorded during each cycle. In both experiments the within-animal correlation between the measured parameters was assessed using a mixed effect model.ResultsIn experiment 1 moderate within-animal correlations were observed between physiological parameters and compression depth (r = 0.69–0.77) and thrust (r = 0.66–0.82). A moderate correlation was observed between compression depth and thrust (r = 0.75). In experiment 2 a strong within-animal correlation and moderate overall correlations were observed between ICG amplitude and compression depth (r = 0.89, r = 0.79) and ETCO₂ (r = 0.85, r = 0.64).ConclusionIn this porcine model of induced cardiac arrest moderate within animal correlations were observed between mechanical and physiological markers of chest compression efficacy demonstrating the challenge in utilising a single mechanical metric to quantify chest compression efficacy. ICG amplitude demonstrated strong within animal correlations with compression depth and ETCO₂ suggesting its potential utility to provide CPR feedback in the out of hospital setting to improve performance.