Supranormal arterial oxygen tension only during the first six hours after cardiac arrest is associated with unfavourable outcomes.

BACKGROUND: Multiple studies have investigated the association between hyperoxaemia following cardiac arrest (CA) and unfavourable outcomes; however, they have yielded inconsistent results. Most previous studies quantified oxygen exposure without considering its timing or duration. We investigated the relationship between unfavourable outcomes and supranormal arterial oxygen tension (PaO2 ), commonly defined as PaO2 > 100 mmHg, at specific time intervals within 24 h following CA. METHODS: This retrospective observational study included 838 adult non-traumatic patients with CA. The first 24 h following CA were divided into four 6-h time intervals, and the first 6-h period was further divided into three 2-h segments. Multivariable logistic regression analyses were conducted to assess associations of the highest PaO2 and time-weighted average PaO2 (TWA-PaO2 ) values at each time interval with unfavourable outcomes at hospital discharge (cerebral performance categories 3-5). RESULTS: The highest PaO2 (p = .028) and TWA-PaO2 (p = .022) values during the 0-6-h time interval were significantly associated with unfavourable outcomes, whereas those at time intervals beyond 6 h were not. The association was the strongest at supranormal PaO2 values within the 0-2-h time interval, becoming significant at PaO2 values ≥ 150 mmHg. During the first 6 h, longer time spent at ≥150 mmHg of PaO2 was associated with an increased risk of unfavourable outcomes (p = .038). The results were consistent across several sensitivity analyses. CONCLUSION: Supranormal PaO2 during but not after the first 6 h following cardiac arrest was independently associated with unfavourable outcomes.

Pralidoxime-Induced Potentiation of the Pressor Effect of Adrenaline and Hastened Successful Resuscitation by Pralidoxime in a Porcine Cardiac Arrest Model.

PURPOSE: Pralidoxime potentiated the pressor effect of adrenaline and facilitated restoration of spontaneous circulation (ROSC) after prolonged cardiac arrest. In this study, we hypothesised that pralidoxime would hasten ROSC in a model with a short duration of untreated ventricular fibrillation (VF). We also hypothesised that potentiation of the pressor effect of adrenaline by pralidoxime would not be accompanied by worsening of the adverse effects of adrenaline. METHODS: After 5 min of VF, 20 pigs randomly received either pralidoxime (40 mg/kg) or saline, in combination with adrenaline, during cardiopulmonary resuscitation (CPR). Coronary perfusion pressure (CPP) during CPR, and ease of resuscitation were compared between the groups. Additionally, haemodynamic data, severity of ventricular arrhythmias, and cerebral microcirculation were measured during the 1-h post-resuscitation period. Cerebral microcirculatory blood flow and brain tissue oxygen tension (PbtO2) were measured on parietal cortices exposed through burr holes. RESULTS: All animals achieved ROSC. The pralidoxime group had higher CPP during CPR (P = 0.014) and required a shorter duration of CPR (P = 0.024) and smaller number of adrenaline doses (P = 0.024). During the post-resuscitation period, heart rate increased over time in the control group, and decreased steadily in the pralidoxime group. No inter-group differences were observed in the incidences of ventricular arrhythmias, cerebral microcirculatory blood flow, and PbtO2. CONCLUSION: Pralidoxime improved CPP and hastened ROSC in a model with a short duration of untreated VF. The potentiation of the pressor effect of adrenaline was not accompanied by the worsening of the adverse effects of adrenaline.

Pralidoxime administered during cardiopulmonary resuscitation facilitates successful resuscitation in a pig model of cardiac arrest.

Pralidoxime is a common antidote for organophosphate poisoning; however, studies have also reported pralidoxime's pressor effect, which may facilitate the restoration of spontaneous circulation (ROSC) after cardiac arrest by improving coronary perfusion pressure (CPP). We investigated the immediate cardiovascular effects of pralidoxime in anaesthetised normal rats and the effects of pralidoxime administration during cardiopulmonary resuscitation (CPR) in a pig model of cardiac arrest. To evaluate the immediate cardiovascular effects of pralidoxime, seven anaesthetised normal rats received saline or pralidoxime (20 mg/kg) in a randomised crossover design, and the responses were determined using the conductance catheter technique. To evaluate the effects of pralidoxime administration during CPR, 22 pigs randomly received either 80 mg/kg of pralidoxime or an equivalent volume of saline during CPR. In the rats, pralidoxime significantly increased arterial pressure than saline (P = .044). The peak effect on arterial pressure was observed in the first minute. In a pig model of cardiac arrest, CPP during CPR was higher in the pralidoxime group than in the control group (P = .002). ROSC was attained in three animals (27.3%) in the control group and nine animals (81.8%) in the pralidoxime group (P = .010). Three animals (27.3%) in the control group and eight animals (72.2%) in the pralidoxime group survived the 6-hour period (P = .033). In conclusion, pralidoxime had a rapid onset of pressor effect. Pralidoxime administered during CPR led to significantly higher rates of ROSC and 6-hour survival by improving CPP in a pig model.

The effectiveness of using magnetic resonance imaging in syncope patients visiting an emergency department: A case-control study.

OBJECTIVE: To evaluate the effectiveness of brain magnetic resonance imaging in excluding neurological causes in patients with syncope. METHODS: This retrospective, observational, cohort study was conducted at the Chonnam National University Hospital, Gwangju, South Korea, and comprised medical record of patients with syncope from January 2011 to February 2016. The ratio of abnormal findings, the characteristics of the patients who showed abnormal findings and the relationships between the presence of neurological problem and other clinical factors were analysed. SPSS 18 was used for statistical analysis. RESULTS: Of the 1,045 patients, 142(13.5%) underwent additional magnetic resonance imaging. The results showed that 15(10.6%) patients had abnormal findings indicating neurological problems; of them, 9(60%) showed vascular stenosis, 4(27%) showed cerebral infarction, and 2(13%) showed brain tumours. The neurological problems shown were significantly higher for older patients (p=0.006) and those with the underlying diseases of hypertension (p=0.014) and coronary artery disease (p=0.008). Of these patients in particular, age (p=0.036) and history of coronary artery disease (p=0.029) were significantly associated with abnormal findings in their magnetic resonance imaging. CONCLUSIONS: Although there are no specific neurological examinations or computed tomography findings currently used in patients with syncope in the emergency department, magnetic resonance imaging may be performed to exclude neurological causes in older patients as well as those with a history of coronary artery disease.

Disseminated intravascular coagulation is associated with the neurologic outcome of cardiac arrest survivors.

PURPOSE: We aimed to examine the serial changes in coagulofibrinolytic markers that occurred after the restoration of spontaneous circulation (ROSC) in cardiac arrest patients, who were treated with targeted temperature management (TTM). We also evaluated the association between the disseminated intravascular coagulation (DIC) score and clinical outcomes. METHODS: This was a single-centre, retrospective observational study that included cardiac arrest patients who were treated with TTM from May 2012 to December 2015. The prothrombin time (PT) and partial thromboplastin time (PTT), along with the levels of fibrinogen, fibrin degradation products (FDP), and D-dimer were obtained after ROSC and on day 1, 2, and 3. The DIC score was calculated after ROSC. The primary outcome was the neurologic outcome at discharge and the secondary outcome was the 6-month mortality. RESULTS: This study included 317 patients. Of these, 222 (70.0%) and 194 (61.2%) patients had a poor neurologic outcome at discharge and 6-month mortality, respectively. The PT, PTT, and fibrinogen level significantly increased over time, while the FDP and D-dimer levels decreased during first three days after ROSC. Multivariate logistic analyses revealed that the DIC score remained a significant predictor for poor neurologic outcome (odds ratio [OR], 1.800; 95% confidence interval [CI], 1.323-2.451) and 6-month mortality (OR, 1.773; 95% CI, 1.307-2.405). CONCLUSION: The activity of coagulation and fibrinolysis decreased over time. An increased DIC score was an independent prognostic factor for poor neurologic outcome and 6-month mortality.

2,3-Butanedione monoxime facilitates successful resuscitation in a dose-dependent fashion in a pig model of cardiac arrest.

PURPOSE: Ischemic contracture compromises the hemodynamic effectiveness of cardiopulmonary resuscitation (CPR) and resuscitability from cardiac arrest. In a pig model of cardiac arrest, 2,3-butanedione monoxime (BDM) attenuated ischemic contracture. We investigated the effects of different doses of BDM to determine whether increasing the dose of BDM could improve the hemodynamic effectiveness of CPR further, thus ultimately improving resuscitability. METHODS: After 16minutes of untreated ventricular fibrillation and 8minutes of basic life support, 36 pigs were divided randomly into 3 groups that received 50mg/kg (low-dose group) of BDM, 100mg/kg (high-dose group) of BDM, or an equivalent volume of saline (control group) during advanced cardiovascular life support. RESULTS: During advanced cardiovascular life support, the control group showed an increase in left ventricular (LV) wall thickness and a decrease in LV chamber area. In contrast, the BDM-treated groups showed a decrease in the LV wall thickness and an increase in the LV chamber area in a dose-dependent fashion. Mixed-model analyses of the LV wall thickness and LV chamber area revealed significant group effects and group-time interactions. Central venous oxygen saturation at 3minutes after the drug administration was 21.6% (18.4-31.9), 39.2% (28.8-53.7), and 54.0% (47.5-69.4) in the control, low-dose, and high-dose groups, respectively (P<.001). Sustained restoration of spontaneous circulation was attained in 7 (58.3%), 10 (83.3%), and 12 animals (100%) in the control, low-dose, and high-dose groups, respectively (P=.046). CONCLUSION: 2,3-Butanedione monoxime administered during CPR attenuated ischemic contracture and improved the resuscitability in a dose-dependent fashion.

Impact of case volume on outcome and performance of targeted temperature management in out-of-hospital cardiac arrest survivors.

PURPOSE: This study aimed to determine the effect of case volume on targeted temperature management (TTM) performance, incidence of adverse events, and neurologic outcome in comatose out-of-hospital cardiac arrest (OHCA) survivors treated with TTM. METHODS: We used a Web-based, multicenter registry (Korean Hypothermia Network registry), to which 24 hospitals throughout the Republic of Korea participated to study adult (≥18 years) comatose out-of-hospital cardiac arrest patients treated with TTM between 2007 and 2012. The primary outcome was neurologic outcome at hospital discharge. The secondary outcomes were inhospital mortality, TTM performance, and adverse events. We extracted propensity-matched cohorts to control for bias. Multivariate logistic regression analysis was performed to assess independent risk factors for neurologic outcome. RESULTS: A total of 901 patients were included in this study; 544 (60.4%) survived to hospital discharge, and 248 (27.5%) were discharged with good neurologic outcome. The high-volume hospitals initiated TTM significantly earlier and had lower rates of hyperglycemia, bleeding, hypotension, and rebound hyperthermia. However, neurologic outcome and inhospital mortality were comparable between high-volume (27.7% and 44.6%, respectively) and low-volume hospitals (21.1% and 40.5%) in the propensity-matched cohorts. The adjusted odds ratio for the high-volume hospitals compared with low-volume hospitals was 1.506 (95% confidence interval, 0.875-2.592) for poor neurologic outcome. CONCLUSIONS: Higher TTM case volume was significantly associated with early initiation of TTM and lower incidence of adverse events. However, case volume had no association with neurologic outcome and inhospital mortality.

Femoral venous oxygen saturation obtained during CPR predicts successful resuscitation in a pig model.

PURPOSE: Central venous oxygen saturation has been shown to reflect the adequacy of tissue oxygenation during cardiopulmonary resuscitation (CPR), thereby enabling the assessment of CPR quality and the prediction of restoration of spontaneous circulation (ROSC). The femoral vein can be easily accessed during CPR. We determined if femoral venous oxygen saturation (SFVO2) values obtained during CPR could reliably predict ROSC in a pig model. METHODS: After 15 minutes of untreated ventricular fibrillation followed by 8 minutes of basic life support, 19 pigs underwent advanced cardiovascular life support. During advanced cardiovascular life support, femoral venous blood samples were obtained at 4-minute intervals. The abilities of SFVO2 and coronary perfusion pressure (CPP) to predict ROSC were evaluated by calculating the areas under receiver operating characteristic curves (AUCs). RESULTS: Eight pigs (42.1%) achieved ROSC. The resuscitated animals had significantly higher CPP (P < .001) and SFVO2 (P < .001) values than the nonresuscitated animals, and there was a significant correlation between SFVO2 and CPP values (r = 0.684; P < .001). The CPPs of the resuscitated and nonresuscitated animals overlapped considerably; however, there was minimal overlap between the 2 groups for SFVO2. Femoral venous oxygen saturation significantly predicted ROSC with an AUC of 0.997 (95% confidence interval, 0.911-1.000; P < .001), and it had a larger AUC than CPP (AUC, 0.964; 95% confidence interval, 0.855-0.997; P < .001). The AUC difference, however, was not statistically significant (P = .157). CONCLUSION: In this study, SFVO2 values obtained during CPR exhibited a significant correlation with CPP and reliably predicted ROSC.

Reliability of blood color and blood gases in discriminating arterial from venous puncture during cardiopulmonary resuscitation.

PURPOSE: We investigated the use of blood color brightness and blood gas variables for discriminating arterial from venous puncture during cardiopulmonary resuscitation (CPR). The study's aims were to determine if discrimination using Po2 is superior to using blood color brightness, and if blood color brightness, Po2, and acid-base variables derived from blood gas analysis accurately discriminate arterial from venous blood during CPR. METHODS: Fifteen pigs underwent ventricular fibrillation followed by CPR. During CPR, paired femoral arterial and venous blood samples were obtained, and 2 blinded observers were asked to identify the blood's origin. Blood color brightness was measured using a blood brightness scale (BBS). The discriminatory performances of the BBS and blood gas variables were evaluated by calculating the area under receiver operating characteristic curves (AUC). RESULTS: The observers accurately discriminated arterial from venous blood with a sensitivity of 97.0% (84.7%-99.5%) and specificity of 84.9% (69.1%-93.4%). The BBS (AUC = 0.983) and Po2 (AUC = 0.981) methods both showed comparable and excellent discriminatory performances. pH, Pco2, and HCO3(-) all discriminated arterial from venous blood (AUC = 0.831, 0.971, and 0.652, respectively). The AUC for Pco2 was comparable to that for Po2 but significantly larger than that for pH (P = .002) or HCO3(-) (P < .001). CONCLUSION: The BBS and Po2 methods showed comparable and excellent discrimination performances. Using pH, Pco2, and HCO3(-) levels also discriminated arterial from venous blood during CPR with statistical significance.

Outcome and adverse events with 72-hour cooling at 32°C as compared to 24-hour cooling at 33°C in comatose asphyxial arrest survivors.

PURPOSE: Studies suggest that the current therapeutic hypothermia (TH) protocol does not improve outcomes in adult asphyxial arrest survivors. We sought to compare the effect of 24-hour cooling at 33°C vs that of 72-hour cooling at 32°C on outcomes and the incidence of adverse events in unconscious asphyxial arrest survivors. METHODS: Retrospectively collected data on 79 consecutive asphyxial arrest patients treated with TH from January 2006 to March 2013 were analyzed. Forty-one patients who presented between January 2006 and January 2011 formed the 33°C-24 h group, whereas 38 patients who presented between February 2011 and March 2013 formed the 32°C-72 h group. The primary outcome was neurologic outcome at 30 days following arrest. The secondary outcomes were all-cause mortality at 30 days following arrest and the incidence of adverse events. RESULTS: The Kaplan-Meier curve showed no significant difference in survival over time during the 30 days after arrest between the 2 groups (P = .608). Good neurologic outcome was achieved in only 2 patients (2.5%) of the overall cohort, despite TH. One of the 32°C-72 h group (2.6%; 95% confidence interval, 4.7%-13.5%) had a good neurologic outcome, as did one of the 33°C-24 h group (2.4%; 95% confidence interval, 4.3%-12.6%) (P = 1.000). There were no significant differences in the rates of adverse events between the 2 groups. CONCLUSION: The present study did not demonstrate an advantage of 72-hour cooling at 32°C in unconscious asphyxial arrest patients compared with 24-hour cooling at 33°C.

Association between mean arterial blood gas tension and outcome in cardiac arrest patients treated with therapeutic hypothermia.

BACKGROUND: Studies investigating the relationship between blood gas tension and outcome in cardiac arrest survivors have reported conflicting results. This might have resulted from the use of a blood gas value at a single time point and the difference in the proportion of patients treated with therapeutic hypothermia (TH). We investigated the association of the mean blood gas tensions calculated from blood gas values obtained between restoration of spontaneous circulation and end of TH with the outcome in cardiac arrest patients treated with TH. METHODS: This was a retrospective observational study including 213 adult cardiac arrest patients. The cohort was divided into four categories based on the distribution of the mean Pao2 data using quartiles as cut-off values between categories. According to the mean Paco2, the cohort was divided into hypocarbia, normocarbia, and hypercarbia. The primary outcome was in-hospital mortality. RESULTS: In multivariate analysis, the mean Pao2 quartile was not associated with in-hospital mortality, but hypocarbia was significantly associated with increased risk of in-hospital mortality (odds ratio 2.522; 95% confidence interval 1.184-5.372; P = .016). We found a V-shaped independent association between the mean Pao2 and poor neurologic outcome at hospital discharge, with the risk of poor neurologic outcome increasing with a descending and ascending Pao2 ranges. CONCLUSION: Mean Pao2 had no independent association with in-hospital mortality whereas hypocarbia was independently associated with in-hospital mortality. We also found a V-shaped independent association between the mean Pao2 and poor neurologic outcome at hospital discharge.

The performances of standard and ResMed masks during bag-valve-mask ventilation.

BACKGROUND: A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. OBJECTIVE: In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. METHODS: Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. RESULTS: BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. CONCLUSIONS: BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

External validation of cardiac arrest-specific prognostication scores developed for early prognosis estimation after out-of-hospital cardiac arrest in a Korean multicenter cohort.

We evaluated the performance of cardiac arrest-specific prognostication scores developed for outcome prediction in the early hours after out-of-hospital cardiac arrest (OHCA) in predicting long-term outcomes using independent data. The following scores were calculated for 1,163 OHCA patients who were treated with targeted temperature management (TTM) at 21 hospitals in South Korea: OHCA, cardiac arrest hospital prognosis (CAHP), C-GRApH (named on the basis of its variables), TTM risk, 5-R, NULL-PLEASE (named on the basis of its variables), Serbian quality of life long-term (SR-QOLl), cardiac arrest survival, revised post-cardiac arrest syndrome for therapeutic hypothermia (rCAST), Polish hypothermia registry (PHR) risk, and PROgnostication using LOGistic regression model for Unselected adult cardiac arrest patients in the Early stages (PROLOGUE) scores and prediction score by Aschauer et al. Their accuracies in predicting poor outcome at 6 months after OHCA were determined using the area under the receiver operating characteristic curve (AUC) and calibration belt. In the complete-case analyses, the PROLOGUE score showed the highest AUC (0.923; 95% confidence interval [CI], 0.904-0.941), whereas the SR-QOLl score had the lowest AUC (0.749; 95% CI, 0.711-0.786). The discrimination performances were similar in the analyses after multiple imputation. The PROLOGUE, TTM risk, CAHP, NULL-PLEASE, 5-R, and cardiac arrest survival scores were well calibrated. The rCAST and PHR risk scores showed acceptable overall calibration, although they showed miscalibration under the 80% CI level at extreme prediction values. The OHCA score, C-GRApH score, prediction score by Aschauer et al., and SR-QOLl score showed significant miscalibration in both complete-case (P = 0.026, 0.013, 0.005, and < 0.001, respectively) and multiple-imputation analyses (P = 0.007, 0.018, < 0.001, and < 0.001, respectively). In conclusion, the discrimination performances of the prognostication scores were all acceptable, but some showed significant miscalibration.

A case of iatrogenic ilio-iliac arteriovenous fistula after percutaneous cardiopulmonary support in a patient with a tortuous iliac artery.

Percutaneous cardiopulmonary support (PCPS) has repeatedly been used with success as a tool for resuscitation in various life-threatening emergencies. PCPS-related vascular injuries are common, but ilio-iliac arteriovenous fistula (AVF) formation after PCPS has not been reported so far. We experienced a case of iatrogenic ilio-iliac AVF after PCPS, in which association between iliac artery tortuosity and AVF formation was strongly suspected. This case suggests that the risk of iatrogenic iliac AVF should be considered when PCPS is performed, especially in elderly patients whose arteries are frequently tortuous.

Association between ion shift index and prognosis in severe trauma patients without isolated head injury.

INTRODUCTION: This study aimed to investigate the ion shift index (ISI) as a prognostic factor of severe trauma. We hypothesized that the initial ISI measured in the emergency department (ED) is associated with discharge survival in severe non-isolated head injury (IHI) patients. MATERIALS AND METHODS: This retrospective observational study included severe trauma patients with available medical records from January 2017 to December 2018 but excluded those with IHI. Logistic regression analysis was conducted to identify the risk factors for mortality in non-IHI patients, and adjustments were performed for relevant covariates. An area under the receiver operating characteristics curve (AUROC) analysis was performed to examine the primary outcome of our study, which was mortality at hospital discharge in severe non-IHI trauma patients. RESULTS: Of the 483 severe non-IHI trauma patients included in the study, 86 patients (17.8 %) died. The multiple logistic regression analysis demonstrated ISI (odds ratio [OR], 2.300; 95% CI, 1.183-4.470) was significantly associated with mortality in the non-IHI group. Additionally, trauma and injury severity score (TRISS; OR, 0.538; 95% CI, 0.447-0.649), lactate (OR, 1.410; 95% CI, 1.252-1.588), creatinine (OR, 1.554; 95% CI, 1.221-1.979), and activated partial thromboplastin time (aPTT; OR, 1.050; 95% CI, 1.021-1.080) were independently associated with mortality at hospital discharge. The AUROC values for TRISS, lactate, aPTT, creatinine, and ISI were as follows: 0.892 (95% CI, 0.861-0.918), 0.838 (95% CI, 0.803-0.870), 0.754 (95% CI, 0.712-0.792), 0.650 (95% CI, 0.606-0.693), and 0.848 (95% CI, 0.813-0.879), respectively. The AUROC for the multiple logistic regression model with ISI was 0.942 (95% CI, 0.917-0.962). In a model in which TRISS was omitted, the addition of ISI to other predictors significantly improved the AUROC to 0.900 (95% CI, 0.869-0.925) (p=0.039). CONCLUSION: The initial ISI in the ED after trauma was associated with mortality in severe non-IHI trauma patients. In conjunction with other prognostic indicators, it could be used as an early prognostic marker, particularly if TRISS is unavailable.

Effect of Epinephrine Administered during Cardiopulmonary Resuscitation on Cerebral Oxygenation after Restoration of Spontaneous Circulation in a Swine Model with a Clinically Relevant Duration of Untreated Cardiac Arrest.

Severe neurological impairment was more prevalent in cardiac arrest survivors who were administered epinephrine than in those administered placebo in a randomized clinical trial; short-term reduction of brain tissue O2 tension (PbtO2) after epinephrine administration in swine following a short duration of untreated cardiac arrest has also been reported. We investigated the effects of epinephrine administered during cardiopulmonary resuscitation (CPR) on cerebral oxygenation after restoration of spontaneous circulation (ROSC) in a swine model with a clinically relevant duration of untreated cardiac arrest. After 7 min of ventricular fibrillation, 24 pigs randomly received either epinephrine or saline placebo during CPR. Parietal cortex measurements during 60-min post-resuscitation period showed that the area under the curve (AUC) for PbtO2 was smaller in the epinephrine group than in the placebo group during the initial 10-min period and subsequent 50-min period (both p < 0.05). The AUC for number of perfused cerebral capillaries was smaller in the epinephrine group during the initial 10-min period (p = 0.005), but not during the subsequent 50-min period. In conclusion, epinephrine administered during CPR reduced PbtO2 for longer than 10 min following ROSC in a swine model with a clinically relevant duration of untreated cardiac arrest.

PROLOGUE (PROgnostication using LOGistic regression model for Unselected adult cardiac arrest patients in the Early stages): Development and validation of a scoring system for early prognostication in unselected adult cardiac arrest patients.

BACKGROUND: Early prognostication after cardiac arrest would be useful. We aimed to develop a scoring model for early prognostication in unselected adult cardiac arrest patients. METHODS: We retrospectively analysed data of adult non-traumatic cardiac arrest patients treated at a tertiary hospital between 2014 and 2018. The primary outcome was poor outcome at hospital discharge (cerebral performance category, 3-5). Using multivariable logistic regression analysis, independent predictors were identified among known outcome predictors, that were available at intensive care unit admission, in patients admitted in the first 3 years (derivation set, N = 671), and a scoring system was developed with the variables that were retained in the final model. The scoring model was validated in patients admitted in the last 2 years (validation set, N = 311). RESULTS: The poor outcome rates at hospital discharge were similar between the derivation (66.0%) and validation sets (64.3%). Age <59 years, witnessed collapse, shockable rhythm, adrenaline dose <2 mg, low-flow duration <18 min, reactive pupillary light reflex, Glasgow Coma Scale motor score ≥2, and levels of creatinine <1.21 mg dl-1, potassium <4.4 mEq l-1, phosphate <5.8 mg dl-1, haemoglobin ≥13.2 g dl-1, and lactate <8 mmol l-1 were retained in the final multivariable model and used to develop the scoring system. Our model demonstrated excellent discrimination in the validation set (area under the curve of 0.942, 95% confidence interval 0.917-0.968). CONCLUSIONS: We developed a scoring model for early prognostication in unselected adult cardiac arrest patients. Further validations in various cohorts are needed.

Relationship of common hemodynamic and respiratory target parameters with brain tissue oxygen tension in the absence of hypoxemia or hypotension after cardiac arrest: A post-hoc analysis of an experimental study using a pig model.

Brain tissue oxygen tension (PbtO2)-guided care, a therapeutic strategy to treat or prevent cerebral hypoxia through modifying determinants of cerebral oxygen delivery, including arterial oxygen tension (PaO2), end-tidal carbon dioxide (ETCO2), and mean arterial pressure (MAP), has recently been introduced. Studies have reported that cerebral hypoxia occurs after cardiac arrest in the absence of hypoxemia or hypotension. To obtain preliminary information on the degree to which PbtO2 is responsive to changes in the common target variables for PbtO2-guided care in conditions without hypoxemia or hypotension, we investigated the relationships between the common target variables for PbtO2-guided care and PbtO2 using data from an experimental study in which the animals did not experience hypoxemia or hypotension after resuscitation. We retrospectively analyzed 170 sets of MAP, ETCO2, PaO2, PbtO2, and cerebral microcirculation parameters obtained during the 60-min post-resuscitation period in 10 pigs resuscitated from ventricular fibrillation cardiac arrest. PbtO2 and cerebral microcirculation parameters were measured on parietal cortices exposed through burr holes. Multiple linear mixed effect models were used to test the independent effects of each variable on PbtO2. Despite the absence of arterial hypoxemia or hypotension, seven (70%) animals experienced cerebral hypoxia (defined as PbtO2 <20 mmHg). Linear mixed effect models revealed that neither MAP nor ETCO2 were related to PbtO2. PaO2 had a significant linear relationship with PbtO2 after adjusting for significant covariates (P = 0.030), but it could explain only 17.5% of the total PbtO2 variance (semi-partial R2 = 0.175; 95% confidence interval, 0.086-0.282). In conclusion, MAP and ETCO2 were not significantly related to PbtO2 in animals without hypoxemia or hypotension during the early post-resuscitation period. PaO2 had a significant linear association with PbtO2, but its ability to explain PbtO2 variance was small.

Pralidoxime improves the hemodynamics and survival of rats with peritonitis-induced sepsis.

Several studies have suggested that sympathetic overstimulation causes deleterious effects in septic shock. A previous study suggested that pralidoxime exerted a pressor effect through a mechanism unrelated to the sympathetic nervous system; this effect was buffered by the vasodepressor action of pralidoxime mediated through sympathoinhibition. In this study, we explored the effects of pralidoxime on hemodynamics and survival in rats with peritonitis-induced sepsis. This study consisted of two sub-studies: survival and hemodynamic studies. In the survival study, 66 rats, which survived for 10 hours after cecal ligation and puncture (CLP), randomly received saline placebo, pralidoxime, or norepinephrine treatment and were monitored for up to 24 hours. In the hemodynamic study, 44 rats were randomly assigned to sham, CLP-saline placebo, CLP-pralidoxime, or CLP-norepinephrine groups, and hemodynamic measurements were performed using a conductance catheter placed in the left ventricle. In the survival study, 6 (27.2%), 15 (68.1%), and 5 (22.7%) animals survived the entire 24-hour monitoring period in the saline, pralidoxime, and norepinephrine groups, respectively (log-rank test P = 0.006). In the hemodynamic study, pralidoxime but not norepinephrine increased end-diastolic volume (P <0.001), stroke volume (P = 0.002), cardiac output (P = 0.003), mean arterial pressure (P = 0.041), and stroke work (P <0.001). The pressor effect of norepinephrine was short-lived, such that by 60 minutes after the initiation of norepinephrine infusion, it no longer had any significant effect on mean arterial pressure. In addition, norepinephrine significantly increased heart rate (P <0.001) and the ratio of arterial elastance to ventricular end-systolic elastance (P = 0.010), but pralidoxime did not. In conclusion, pralidoxime improved the hemodynamics and 24-hour survival rate in rats with peritonitis-induced sepsis, but norepinephrine did not.

Early Post-Rewarming Fever Is Associated with Favorable 6-Month Neurologic Outcomes in Patients with Out-Of-Hospital Cardiac Arrest: A Multicenter Registry Study.

We investigated the association between post-rewarming fever (PRF) and 6-month neurologic outcomes in cardiac arrest survivors. This was a multicenter study based on a registry of comatose adult (≥18 years) out-of-hospital cardiac arrest (OHCA) survivors who underwent targeted temperature management between October 2015 to December 2018. PRF was defined as peak temperature ≥ 38.0 °C within 72 h after completion of rewarming, and PRF timing was categorized as within 24, 24-48, and 48-72 h epochs. The primary outcome was neurologic outcomes at six months after cardiac arrest. Unfavorable neurologic outcome was defined as cerebral performance categories three to five. A total of 1031 patients were included, and 642 (62.3%) had unfavorable neurologic outcomes. PRF developed in 389 (37.7%) patients in 72 h after rewarming: within 24 h in 150 (38.6%), in 24-48 h in 155 (39.8%), and in 48-72 h in 84 (21.6%). PRF was associated with improved neurologic outcomes (odds ratio (OR), 0.633; 95% confidence interval (CI), 0.416-0.963). PRF within 24 h (OR, 0.355; 95% CI, 0.191-0.659), but not in 24-48 h or 48-72 h, was associated with unfavorable neurologic outcomes. Early PRF within 24 h after rewarming was associated with favorable neurologic outcomes.