The Role of Phospholipid Alterations in Mitochondrial and Brain Dysfunction after Cardiac Arrest

The human brain possesses three predominate phospholipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS), which account for approximately 35-40%, 35-40%, and 20% of the brain's phospholipids, respectively. Mitochondrial membranes are relatively diverse, containing the aforementioned PC, PE, and PS, as well as phosphatidylinositol (PI) and phosphatidic acid (PA); however, cardiolipin (CL) and phosphatidylglycerol (PG) are exclusively present in mitochondrial membranes. These phospholipid interactions play an essential role in mitochondrial fusion and fission dynamics, leading to the maintenance of mitochondrial structural and signaling pathways. The essential nature of these phospholipids is demonstrated through the inability of mitochondria to tolerate alteration in these specific phospholipids, with changes leading to mitochondrial damage resulting in neural degeneration. This review will emphasize how the structure of phospholipids relates to their physiologic function, how their metabolism facilitates signaling, and the role of organ- and mitochondria-specific phospholipid compositions. Finally, we will discuss the effects of global ischemia and reperfusion on organ- and mitochondria-specific phospholipids alongside the novel therapeutics that may protect against injury.

Should Transport Ventilators Be Used in Times of Crisis? The Use of Emergency Authorized Nonconventional Ventilators Is Associated With Mortality Among Patients With COVID-19 Acute Respiratory Distress Syndrome

OBJECTIVES

Nonconventional ventilators (NCVs), defined here as transport ventilators and certain noninvasive positive pressure devices, were used extensively as crisis-time ventilators for intubated patients with COVID-19. We assessed whether there was an association between the use of NCV and higher mortality, independent of other factors.

DESIGN

This is a multicenter retrospective observational study.

SETTING

The sample was recruited from a single healthcare system in New York. The recruitment period spanned from March 1, 2020, to April 30, 2020.

PATIENTS

The sample includes patients who were intubated for COVID-19 acute respiratory distress syndrome (ARDS).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was 28-day in-hospital mortality. Multivariable logistic regression was used to derive the odds of mortality among patients managed exclusively with NCV throughout their ventilation period compared with the remainder of the sample while adjusting for other factors. A secondary analysis was also done, in which the mortality of a subset of the sample exclusively ventilated with NCV was compared with that of a propensity score-matched subset of the control group. Exclusive use of NCV was associated with a higher 28-day in-hospital mortality while adjusting for confounders in the regression analysis (odds ratio, 1.41; 95% CI [1.07-1.86]). In the propensity score matching analysis, the mortality of patients exclusively ventilated with NCV was 68.9%, and that of the control was 60.7% (p = 0.02).

CONCLUSIONS

Use of NCV was associated with increased mortality among patients with COVID-19 ARDS. More lives may be saved during future ventilator shortages if more full-feature ICU ventilators, rather than NCVs, are reserved in national and local stockpiles.

The Current Discussion Regarding End-of-Life Care for Patients with Out-of-Hospital Cardiac Arrest with Initial Non-Shockable Rhythm: A Narrative Review

Despite recent advances in resuscitation science, outcomes in patients with out-of-hospital cardiac arrest (OHCA) with initial non-shockable rhythm remains poor. Those with initial non-shockable rhythm have some epidemiological features, including the proportion of patients with a witnessed arrest, bystander cardiopulmonary resuscitation (CPR), age, and presumed etiology of cardiac arrest have been reported, which differ from those with initial shockable rhythm. The discussion regarding better end-of-life care for patients with OHCA is a major concern among citizens. As one of the efforts to avoid unwanted resuscitation, advance directive is recognized as a key intervention, safeguarding patient autonomy. However, several difficulties remain in enhancing the effective use of advance directives for patients with OHCA, including local regulation of their use, insufficient utilization of advance directives by emergency medical services at the scene, and a lack of established tools for discussing futility of resuscitation in advance care planning. In addition, prehospital termination of resuscitation is a common practice in many emergency medical service systems to assist clinicians in deciding whether to discontinue resuscitation. However, there are also several unresolved problems, including the feasibility of implementing the rules for several regions and potential missed survivors among candidates for prehospital termination of resuscitation. Further investigation to address these difficulties is warranted for better end-of-life care of patients with OHCA.

Wolf Creek XVII part 9: Wolf Creek Innovator in Cardiac Arrest and Resuscitation Science Award

The Wolf Creek Conferences on Cardiac Arrest Resuscitation began in 1975, and have served as an important forum for thought leaders and scientists from industry and academia to come together with the common goal of advancing the field of cardiac arrest resuscitation. The Wolf Creek XVII Conference was hosted by the Max Harry Weil Institute of Critical Care Research and Innovation in Ann Arbor, Michigan on June 14-17, 2023. A new component of the conference was the Wolf Creek Innovator in Cardiac Arrest and Resuscitation Science Award competition. The competition was designed to recognize early career investigators from around the world who's science is challenging the current paradigms in the field. Finalists were selected by a panel of international experts and invited to present in-person at the conference. The winner was chosen by electronic vote of conference participants and awarded a $10,0000 cash prize. Finalists included Carolina Barbosa Maciel from the University of Florida, Adam Gottula from the University of Michigan, Rajat Kalra from the University of Minnesota, Ryan Morgan from the Children's Hospital of Philadelphia, Mitsuaki Nishikimi form Hiroshima University, and Jacob Sunshine from the University of Washington. Ryan Morgan from the Children's Hospital of Philadelphia was selected as the 2023 Wolf Creek Innovator Awardee. This manuscript provides a summary of the work presented by each of the finalists and provides a preview of the future of resuscitation science.

External validation of the rCAST for patients after in-hospital cardiac arrest: a multicenter retrospective observational study

No established predictive or risk classification tool exists for the neurological outcomes of post-cardiac arrest syndrome (PCAS) in patients with in-hospital cardiac arrest (IHCA). This study aimed to investigate whether the revised post-cardiac arrest syndrome for therapeutic hypothermia score (rCAST), which was developed to estimate the prognosis of PCAS patients with out-of-hospital cardiac arrest (OHCA), was applicable to patients with IHCA. A retrospective, multicenter observational study of 140 consecutive adult IHCA patients admitted to three intensive care units. The area under the receiver operating characteristic curves (AUCs) of the rCAST for poor neurological outcome and mortality at 30 days were 0.88 (0.82-0.93) and 0.83 (0.76-0.89), respectively. The sensitivity and specificity of the risk classification according to rCAST for poor neurological outcomes were 0.90 (0.83-0.96) and 0.67 (0.55-0.79) for the low, 0.63 (0.54-0.74) and 0.67 (0.55-0.79) for the moderate, and 0.27 (0.17-0.37) and 1.00 (1.00-1.00) for the high-severity grades. All 22 patients classified with a high-severity grade showed poor neurological outcomes. The rCAST showed excellent predictive accuracy for neurological prognosis in patients with PCAS after IHCA. The rCAST may be useful as a risk classification tool for PCAS after IHCA.

Association between hospital volume and in-hospital mortality in pediatric severe traumatic brain injury: a nationwide retrospective observational study in Japan

OBJECTIVE

The objective of this study was to investigate the association between hospital volume and in-hospital mortality in pediatric patients with severe traumatic brain injury (TBI).

METHODS

This retrospective cohort study used data from the Japan Trauma Data Bank between 2010 and 2018, specifically those of pediatric patients with severe TBI (Glasgow Coma Scale [GCS] score < 9 and head Abbreviated Injury Scale score > 2). Hospital volume was defined as the number of pediatric patients with severe TBI throughout the study period. Hospital volume was categorized as low (reference category: 1-9 patients), middle (10-17 patients), or high (> 18 patients) volume. Multivariate mixed-effects logistic regression analysis was performed to determine the association between hospital volume categories and in-hospital mortality. Subgroup analyses were performed using data on craniotomy and the presence of severe torso injuries. In the sensitivity analyses, patients with a GCS score of 3, interhospital transfer, and major intensive care unit complications were excluded.

RESULTS

A total of 1148 pediatric patients with severe TBI, with a median age of 12 years (IQR 7-16 years), treated at 141 hospitals were included. In total, 236 patients (20.6%) died in the hospital. Multivariate analysis showed no significant association between hospital volume and in-hospital mortality (high volume: OR 1.15, 95% CI 0.80-1.64; middle volume: OR 0.89, 95% CI 0.62-1.26). Subgroup and sensitivity analyses showed similar results.

CONCLUSIONS

Hospital volume may not be associated with in-hospital mortality in pediatric patients with severe TBI.

Association between regional critical care capacity and the incidence of invasive mechanical ventilation for coronavirus disease 2019: a population-based cohort study

BACKGROUND

Coronavirus disease 2019 (COVID-19) has exposed critical care supply shortages worldwide. This study aimed to investigate the association between regional critical care capacity and the incidence of invasive mechanical ventilation following novel COVID-19 during the pandemic in Japan, a country with a limited intensive care unit (ICU) bed capacity of a median of 5.1 ICU beds per 100,000 individuals.

METHODS

This population-based cohort study used data from the CRoss Icu Searchable Information System database and publicly available databases provided by the Japanese government and Japanese Society of Intensive Care Medicine. We identified patients recently diagnosed with COVID-19, those who received invasive mechanical ventilation, and those who received extracorporeal membrane oxygenation (ECMO) between February 2020 and March 2023. We analyzed the association between regional critical care capacity (ICU beds, high-dependency care unit (HDU) beds, resource-rich ICU beds, and intensivists) and the incidence of invasive mechanical ventilation, ECMO, and risk-adjusted mortality across 47 Japanese prefectures.

RESULTS

Among the approximately 127 million individuals residing in Japan, 33,189,809 were recently diagnosed with COVID-19, with 12,203 and 1,426 COVID-19 patients on invasive mechanical ventilation and ECMO, respectively, during the study period. Prefecture-level linear regression analysis revealed that the addition of ICU beds, resource-rich ICU beds, and intensivists per 100,000 individuals increased the incidence of IMV by 5.37 (95% confidence interval, 1.99-8.76), 7.27 (1.61-12.9), and 13.12 (3.48-22.76), respectively. However, the number of HDU beds per 100,000 individuals was not statistically significantly associated with the incidence of invasive mechanical ventilation. None of the four indicators of regional critical care capacity was statistically significantly associated with the incidence of ECMO and risk-adjusted mortality.

CONCLUSIONS

The results of prefecture-level analyses demonstrate that increased numbers of ICU beds, resource-rich ICU beds, and intensivists are associated with the incidence of invasive mechanical ventilation among patients recently diagnosed with COVID-19 during the pandemic. These findings have important implications for healthcare policymakers, aiding in efficiently allocating critical care resources during crises, particularly in regions with limited ICU bed capacities. Registry and the registration no. of the study/trial The approval date of the registry was August 20, 2020, and the registration no. of the study was lUMIN000041450.

Chest CT findings in severe acute respiratory distress syndrome requiring V-V ECMO: J-CARVE registry

BACKGROUND

Chest computed tomography findings are helpful for understanding the pathophysiology of severe acute respiratory distress syndrome (ARDS). However, there is no large, multicenter, chest computed tomography registry for patients requiring veno-venous extracorporeal membrane oxygenation (V-V ECMO). The aim of this study was to describe chest computed tomography findings at V-V ECMO initiation and to evaluate the association between the findings and outcomes in severe ARDS.

METHODS

This multicenter, retrospective cohort study enrolled patients with severe ARDS on V-V ECMO, who were admitted to the intensive care units of 24 hospitals in Japan between January 1, 2012, and December 31, 2022.

RESULTS

The primary outcome was 90-day in-hospital mortality. The secondary outcomes were the successful liberation from V-V ECMO and the values of static lung compliance. Among the 697 registry patients, of the 582 patients who underwent chest computed tomography at V-V ECMO initiation, 394 survived and 188 died. Multivariate Cox regression showed that traction bronchiectasis and subcutaneous emphysema increased the risk of 90-day in-hospital mortality (hazard ratio [95% confidence interval] 1.77 [1.19-2.63], p = 0.005 and 1.97 [1.02-3.79], p = 0.044, respectively). The presence of traction bronchiectasis was also associated with decreased successful liberation from V-V ECMO (odds ratio: 0.27 [0.14-0.52], p < 0.001). Lower static lung compliance was associated with some chest computed tomography findings related to changes outside of pulmonary opacity, but not with the findings related to pulmonary opacity.

CONCLUSIONS

Traction bronchiectasis and subcutaneous emphysema increased the risk of 90-day in-hospital mortality in patients with severe ARDS who required V-V ECMO.

Prediction of the neurological outcomes post-cardiac arrest: A prospective validation of the CAST and rCAST

INTRODUCTION

The neurologic prognosis of out-of-hospital cardiac arrest (OHCA) patients in whom return of spontaneous circulation (ROSC) is achieved remains poor. The aim of this study was to externally and prospectively validate two scoring systems developed by us: the CAST score, a scoring system to predict the neurological prognosis of OHCA patients undergoing targeted temperature management (TTM), and a simplified version of the same score developed for improved ease of use in clinical settings, the revised CAST (rCAST) score.

METHODS

This study was a prospective, multicenter, observational study conducted using the SOS KANTO 2017 registry, an OHCA registry involving hospitals in the Kanto region (including Tokyo) of Japan. The primary outcome was favorable neurological outcome (defined as Cerebral Performance Category score of 1 or 2) at 30 days and the secondary outcomes were favorable neurological outcome at 90 days and survival at 30 and 90 days. The predictive accuracies of the original CAST (oCAST) and rCAST scores were evaluated by using area under the receiver operating characteristic curve (AUC).

RESULTS

Of 9909 OHCA patients, 565 showed ROSC and received TTM. Of these, we analyzed the data of 259 patients in this study. The areas under the receiver operating characteristic curve (AUCs) of the oCAST and rCAST scores for predicting a favorable neurological outcome at 30 days were 0.86 and 0.87, respectively, and those for predicting a favorable neurological outcome at 90 days were 0.87 and 0.88, respectively. The rCAST showed a higher predictive accuracy for the neurological outcome as compared with the NULL-PLEASE score. The patients with a favorable neurological outcome who had been classified into the high severity group based on the rCAST tended to have hypothermia at hospital arrival and to not show any signs of loss of gray-white matter differentiation on brain CT. Neurological function at 90 days was correlated with the rCAST (r = 0.63, p < 0.001).

CONCLUSIONS

rCAST showed high predictive accuracy for the neurological prognosis of OHCA patients managed by TTM, comparable to that of the oCAST score. The scores on the rCAST were strongly correlated with the neurological functions at 90 days, implying that the rCAST is a useful scale for assessing the severity of brain injury after cardiac arrest.

Neurological Improvement via Lysophosphatidic Acid Administration in a Rodent Model of Cardiac Arrest-Induced Brain Injury

Lysophosphatidic acid (LPA) serves as a fundamental constituent of phospholipids. While prior studies have shown detrimental effects of LPA in a range of pathological conditions, including brain ischemia, no studies have explored the impact of LPA in the context of cardiac arrest (CA). The aim of this study is to evaluate the effects of the intravenous administration of an LPA species containing oleic acid, LPA (18:1) on the neurological function of rats (male, Sprague Dawley) following 8 min of asphyxial CA. Baseline characteristics, including body weight, surgical procedure time, and vital signs before cardiac arrest, were similar between LPA (18:1)-treated (n = 10) and vehicle-treated (n = 10) groups. There was no statistically significant difference in 24 h survival between the two groups. However, LPA (18:1)-treated rats exhibited significantly improved neurological function at 24 h examination (LPA (18:1), 85.4% ± 3.1 vs. vehicle, 74.0% ± 3.3, p = 0.045). This difference was most apparent in the retention of coordination ability in the LPA (18:1) group (LPA (18:1), 71.9% ± 7.4 vs. vehicle, 25.0% ± 9.1, p < 0.001). Overall, LPA (18:1) administration in post-cardiac arrest rats significantly improved neurological function, especially coordination ability at 24 h after cardiac arrest. LPA (18:1) has the potential to serve as a novel therapeutic in cardiac arrest.

COVID-19-Associated Portal Vein Thrombosis Post-Cholecystitis

This case study describes a 45-year-old Caucasian male with a past medical history of obesity, hypertension, and non-insulin-dependent diabetes mellitus, who in the setting of coronavirus disease 2019 (COVID-19) pneumonia, developed portal vein thrombosis (PVT) presenting as an acute abdomen after hospital discharge from a cholecystitis episode. PVT is a very infrequent thromboembolic condition, classically occurring in patients with systemic conditions such as cirrhosis, malignancy, pancreatitis, diverticulitis, autoimmunity, and thrombophilia. PVT can cause serious complications, such as intestinal infarction, or even death, if not promptly treated. Due to the limited number of reports in the literature describing PVT in the COVID-19 setting, its prevalence, natural history, mechanism, and precise clinical features remain unknown. Therefore, clinical suspicion should be high for PVT, in any COVID-19 patient who presents with abdominal pain or associated signs and symptoms. To the best of our knowledge, this is the first report of COVID-19-associated PVT causing extensive thrombosis in the portal vein and its right branch, occurring in the setting of early-stage cirrhosis after a preceding episode of cholecystitis.

Instruments to assess post-intensive care syndrome assessment: a scoping review and modified Delphi method study

BACKGROUND

The assessment of post-intensive care syndrome (PICS) is challenging due to the numerous types of instruments. We herein attempted to identify and propose recommendations for instruments to assess PICS in intensive care unit (ICU) survivors.

METHODS

We conducted a scoping review to identify PICS follow-up studies at and after hospital discharge between 2014 and 2022. Assessment instruments used more than two times were included in the modified Delphi consensus process. A modified Delphi meeting was conducted three times by the PICS committee of the Japanese Society of Intensive Care Medicine, and each score was rated as not important (score: 1-3), important, but not critical (4-6), and critical (7-9). We included instruments with ≥ 70% of respondents rating critical and ≤ 15% of respondents rating not important.

RESULTS

In total, 6972 records were identified in this scoping review, and 754 studies were included in the analysis. After data extraction, 107 PICS assessment instruments were identified. The modified Delphi meeting reached 20 PICS assessment instrument recommendations: (1) in the physical domain: the 6-min walk test, MRC score, and grip strength, (2) in cognition: MoCA, MMSE, and SMQ, (3) in mental health: HADS, IES-R, and PHQ-9, (4) in the activities of daily living: the Barthel Index, IADL, and FIM, (5) in quality of life: SF-36, SF-12, EQ-5D-5L, 3L, and VAS (6), in sleep and pain: PSQI and Brief Pain Inventory, respectively, and (7) in the PICS-family domain: SF-36, HADS, and IES-R.

CONCLUSION

Based on a scoping review and the modified Delphi method, 20 PICS assessment instruments are recommended to assess physical, cognitive, mental health, activities of daily living, quality of life, sleep, and pain in ICU survivors and their families.

High versus low positive end-expiratory pressure setting in patients receiving veno-venous extracorporeal membrane oxygenation support for severe acute respiratory distress syndrome: study protocol for the multicentre, randomised ExPress SAVER Trial

INTRODUCTION

While limiting the tidal volume to 6 mL/kg during veno-venous extracorporeal membrane oxygenation (V-V ECMO) to ameliorate lung injury in patients with acute respiratory distress syndrome (ARDS) is widely accepted, the best setting for positive end-expiratory pressure (PEEP) is still controversial. This study is being conducted to investigate whether a higher PEEP setting (15 cmH2O) during V-V ECMO can decrease the duration of ECMO support needed in patients with severe ARDS, as compared with a lower PEEP setting.

METHODS AND ANALYSIS

The study is an investigator-initiated, multicentre, open-label, two-arm, randomised controlled trial conducted with the participation of 20 intensive care units (ICUs) at academic as well as non-academic hospitals in Japan. The subjects of the study are patients with severe ARDS who require V-V ECMO support. Eligible patients will be randomised equally to the high PEEP group or low PEEP group. Recruitment to the study will continue until a total of 210 patients with ARDS requiring V-V ECMO support have been randomised. In the high PEEP group, PEEP will be set at 15 cmH2O from the start of V-V ECMO until the trials for liberation from V-V ECMO (or until day 28 after the allocation), while in the low PEEP group, the PEEP will be set at 5 cmH2O. Other treatments will be the same in the two groups. The primary endpoint of the study is the number of ECMO-free days until day 28, defined as the length of time (in days) from successful libration from V-V ECMO to day 28. The secondary endpoints are mortality on day 28, in-hospital mortality on day 60, ventilator-free days during the first 60 days and length of ICU stay.

ETHICS AND DISSEMINATION

Ethics approval for the trial at all the participating hospitals was obtained on 27 September 2022, by central ethics approval (IRB at Hiroshima University Hospital, C2022-0006). The results of this study will be presented at domestic and international medical congresses, and also published in scientific journals.

TRIAL REGISTRATION NUMBER

The Japan Registry of Clinical Trials jRCT1062220062. Registered on 28 September 2022.

PROTOCOL VERSION

28 March 2023, version 4.0.

Multi-Drug Cocktail Therapy Improves Survival and Neurological Function after Asphyxial Cardiac Arrest in Rodents

BACKGROUND

Cardiac arrest (CA) can lead to neuronal degeneration and death through various pathways, including oxidative, inflammatory, and metabolic stress. However, current neuroprotective drug therapies will typically target only one of these pathways, and most single drug attempts to correct the multiple dysregulated metabolic pathways elicited following cardiac arrest have failed to demonstrate clear benefit. Many scientists have opined on the need for novel, multidimensional approaches to the multiple metabolic disturbances after cardiac arrest. In the current study, we have developed a therapeutic cocktail that includes ten drugs capable of targeting multiple pathways of ischemia-reperfusion injury after CA. We then evaluated its effectiveness in improving neurologically favorable survival through a randomized, blind, and placebo-controlled study in rats subjected to 12 min of asphyxial CA, a severe injury model.

RESULTS

14 rats were given the cocktail and 14 received the vehicle after resuscitation. At 72 h post-resuscitation, the survival rate was 78.6% among cocktail-treated rats, which was significantly higher than the 28.6% survival rate among vehicle-treated rats (log-rank test; p = 0.006). Moreover, in cocktail-treated rats, neurological deficit scores were also improved. These survival and neurological function data suggest that our multi-drug cocktail may be a potential post-CA therapy that deserves clinical translation.

CONCLUSIONS

Our findings demonstrate that, with its ability to target multiple damaging pathways, a multi-drug therapeutic cocktail offers promise both as a conceptual advance and as a specific multi-drug formulation capable of combatting neuronal degeneration and death following cardiac arrest. Clinical implementation of this therapy may improve neurologically favorable survival rates and neurological deficits in patients suffering from cardiac arrest.

Predictive Accuracy of the Breathing Frequency-Ratio of Oxygen Saturation Index for Re-Intubation in Mechanically Ventilated Subjects With COVID-19

BACKGROUND

Several studies have suggested that high-flow nasal cannula (HFNC) is useful for respiratory support after extubation in subjects with COVID-19 pneumonia, whereas 18.2% subsequently needed to undergo re-intubation. This study aimed to evaluate whether the breathing frequency (f)-ratio of oxygen saturation (ROX) index, which has been shown to be useful for predicting future intubation, is also useful for re-intubation in subjects with COVID-19.

METHODS

We retrospectively analyzed mechanically ventilated subjects with COVID-19 who underwent HFNC therapy after extubation at 4 participating hospitals between January 2020-May 2022. We evaluated the predictive accuracy of ROX at 0, 1, and 2 h for re-intubation until ICU discharge and compared the area under the receiver operating characteristic (ROC) curve of the ROX index with those of f and S_pO2 /F_IO2 .

RESULTS

Among the 248 subjects with COVID-19 pneumonia, 44 who underwent HFNC therapy after extubation were included. A total of 32 subjects without re-intubation were classified into the HFNC success group, and 12 with re-intubation were classified into the failure group. The overall trend that the area under the ROC curve of the ROX index was greater than that of the f and S_aO2 /F_IO2 was observed, although there was no statistical significance at any time point. The ROX index at 0 h, at the cutoff point of < 7.44, showed a sensitivity and specificity of 0.42 and 0.97, respectively. A trend of positive correlation between the time until re-intubation and ROX index at each time point was observed.

CONCLUSIONS

The ROX index in the early phase of HFNC therapy after extubation was useful for predicting re-intubation with high accuracy in mechanically ventilated subjects with COVID-19. We may need close observation for subjects with < 7.44 ROX index just after extubation because of their high risk for re-intubation.

Characteristics of the pulmonary opacities on chest CT associated with difficulty in short-term liberation from veno-venous ECMO in patients with severe ARDS

BACKGROUND

It is clinically important to predict difficulty in short-term liberation from veno-venous extracorporeal membrane oxygenation (V-V ECMO) in patients with severe acute respiratory distress syndrome (ARDS) at the time of initiation of the support. The aim of this study was to identify the characteristics of pulmonary opacities on chest CT that is associated with difficulty in short-term liberation from V-V ECMO (< 14 days).

METHODS

This multicenter retrospective study was conducted in adult patients initiated on V-V ECMO for severe ARDS between January 2014 and June 2022. The pulmonary opacities on CT at the time of initiation of the ECMO support were evaluated in a blinded manner, focusing on the following three characteristics of the opacities: (1) their distribution (focal/diffuse on the dorso-ventral axis or unilateral/bilateral on the left-right axis); (2) their intensity (pure ground glass/pure consolidation/mixed pattern); and (3) the degree of fibroproliferation (signs of traction bronchiectasis or reticular opacities).

RESULTS

Among the 153 patients, 72 (47%) were successfully liberated from ECMO in the short term, while short-term liberation failed in the remaining 81 (53%) patients. Multivariate logistic regression analysis showed that the presence of mixed-pattern pulmonary opacities and signs of traction bronchiectasis, but not the distribution of the opacities, were independently associated with difficulty in short-term liberation (OR [95% CI]; 4.8 [1.4-16.5] and 3.9 [1.4-11.2], respectively).

CONCLUSIONS

The presence of a mixed pattern of the pulmonary opacities and signs of traction bronchiectasis on the chest CT were independently associated with difficulty in short-term liberation from V-V ECMO in severe ARDS patients.

Lung Abscess and Pyothorax in Critically Ill COVID-19 Patients: A Single-Center Retrospective Study

The mortality rate of patients with COVID-19 pneumonia requiring mechanical ventilation remains high. This study determined the percentage and characteristics of patients who developed lung abscesses or pyothorax and their mortality rates among adult patients with COVID-19 admitted to the ICU who required mechanical ventilation. Of the 64 patients with COVID-19 assessed, 30 (47%) developed ventilator-associated pneumonia (VAP), of whom 6 (20%) developed pyothorax or lung abscess. There were no statistically significant differences in patient characteristics, treatment after ICU admission, or outcomes between those with and without these complications, except for age. VAP complicated by Lung abscess or pyothorax was caused by a single organism, with Staphylococcus aureus (n = 4) and Klebsiella species (n = 2) being the primary causative agents. Occur infrequently in patients with COVID-19 requiring mechanical ventilation. Large-scale studies are required to elucidate their effects on clinical outcomes.

Continuously increased generation of ROS in human plasma after cardiac arrest as determined by Amplex Red oxidation

Oxidative stress is believed to be a major cause of injury after cardiac arrest (CA). While the effects of ROS generated within tissues have been extensively investigated, the potential of plasma-generated ROS in contributing to CA pathology has not been examined. We utilized Amplex Red (AR) to measure the real time-generation of ROS in isolated plasma from human CA patients. We first used post-CA rat plasma to identify interfering factors for AR oxidation, and then applied this knowledge to analyze human plasma samples, accounting for the identified confounders. We found significantly increased AR oxidation rates lasting for 4 h in post-CA rat plasma compared to baseline. AR oxidation was unchanged with removal of horseradish peroxidase or addition of catalase. However, adding carboxylesterase inhibitors significantly decreased AR oxidation in rat plasma, which implicated increased carboxylesterase activity, not ROS leading to increased AR oxidation. AR oxidation rates were also significantly increased in human CA patient plasma compared to control and this increase persisted even with carboxylesterase inhibition, suggesting continuously increased ROS-generation within plasma post-CA in humans. The increased ROS generation may be one major source of injury post-CA that may be mitigated with antioxidative therapeutic strategies that can manage the ROS systemically generated in plasma over time.KEY POLICY HIGHLIGHTSWe examined the potential of plasma as a source of ROS generation post-cardiac arrestRat cardiac arrest was used to guide the application of Amplex Red in human plasmaROS generation in plasma is significantly increased after cardiac arrest in humansScavenging excessive ROS in post-resuscitation plasma may improve outcomes of patients.

Exogenous mitochondrial transplantation improves survival and neurological outcomes after resuscitation from cardiac arrest

BACKGROUND

Mitochondrial transplantation (MTx) is an emerging but poorly understood technology with the potential to mitigate severe ischemia-reperfusion injuries after cardiac arrest (CA). To address critical gaps in the current knowledge, we test the hypothesis that MTx can improve outcomes after CA resuscitation.

METHODS

This study consists of both in vitro and in vivo studies. We initially examined the migration of exogenous mitochondria into primary neural cell culture in vitro. Exogenous mitochondria extracted from the brain and muscle tissues of donor rats and endogenous mitochondria in the neural cells were separately labeled before co-culture. After a period of 24 h following co-culture, mitochondrial transfer was observed using microscopy. In vitro adenosine triphosphate (ATP) contents were assessed between freshly isolated and frozen-thawed mitochondria to compare their effects on survival. Our main study was an in vivo rat model of CA in which rats were subjected to 10 min of asphyxial CA followed by resuscitation. At the time of achieving successful resuscitation, rats were randomly assigned into one of three groups of intravenous injections: vehicle, frozen-thawed, or fresh viable mitochondria. During 72 h post-CA, the therapeutic efficacy of MTx was assessed by comparison of survival rates. The persistence of labeled donor mitochondria within critical organs of recipient animals 24 h post-CA was visualized via microscopy.

RESULTS

The donated mitochondria were successfully taken up into cultured neural cells. Transferred exogenous mitochondria co-localized with endogenous mitochondria inside neural cells. ATP content in fresh mitochondria was approximately four times higher than in frozen-thawed mitochondria. In the in vivo survival study, freshly isolated functional mitochondria, but not frozen-thawed mitochondria, significantly increased 72-h survival from 55 to 91% (P = 0.048 vs. vehicle). The beneficial effects on survival were associated with improvements in rapid recovery of arterial lactate and glucose levels, cerebral microcirculation, lung edema, and neurological function. Labeled mitochondria were observed inside the vital organs of the surviving rats 24 h post-CA.

CONCLUSIONS

MTx performed immediately after resuscitation improved survival and neurological recovery in post-CA rats. These results provide a foundation for future studies to promote the development of MTx as a novel therapeutic strategy to save lives currently lost after CA.

The finger-to-nose test improved diagnosis of cerebrovascular events in patients presenting with isolated dizziness in the emergency department

It is difficult to identify patients with isolated dizziness caused by cerebrovascular events. The estimated risk of cerebrovascular events in isolated dizziness patients is not completely understood. We aimed to evaluate the association of the finger-to-nose test (FNT) in diagnosing cerebrovascular events in isolated dizziness patients in emergency departments (EDs). We combined 2 datasets from a single center for consecutive isolated dizziness patients, with the same inclusion and exclusion criteria. Those who met any of the following criteria were excluded: no FNT data, age < 16 years, and psychological trauma. The primary outcome was cerebrovascular event, which was defined as cerebral stroke due to cerebral infarction, cerebral hemorrhage, vertebral artery dissection, or transient ischemic attack. In the combined dataset, there were 357 patients complaining of isolated dizziness and 31 cerebrovascular events. After adjusted by 5 previously reported risk factors for cerebrovascular event, (age, hypertension, hyperlipidemia, diabetes mellitus, nystagmus), a multivariable logistic model analysis showed that the existence of FNT abnormalities was significantly associated with cerebrovascular events (odds ratio, 25.3; 95% confidence interval, 7.3-88.2; p < 0.001). There was a significant increase in predictive accuracy, with an AUC increase of 0.116 in the in a ROC analysis (p = 0.023). The existence of FNT abnormalities is considered as a strong risk factor that could be useful for predicting cerebrovascular events in isolated dizziness patients. We recommend the FNT for screening isolated dizziness patients in EDs to judge whether they need to undergo further diagnostic evaluation.

Prediction of Prehospital Change of the Cardiac Rhythm From Nonshockable to Shockable in Out-of-Hospital Patients With Cardiac Arrest: A Post Hoc Analysis of a Nationwide, Multicenter, Prospective Registry

Background

Predicting a spontaneous rhythm change from nonshockable to shockable before hospital arrival in patients with out‐of‐hospital cardiac arrest can help emergency medical services develop better strategies for prehospital treatment. The aim of this study was to identify predictors of spontaneous rhythm change before hospital arrival in patients with out‐of‐hospital cardiac arrest and develop a predictive scoring system.

Methods and Results

We retrospectively reviewed data of eligible patients with out‐of‐hospital cardiac arrest with an initial nonshockable rhythm registered in a nationwide registry between June 2014 and December 2017. We performed a multivariable analysis using a Cox proportional hazards model to identify predictors of a spontaneous rhythm change, and a ridge regression model for predicting it. The data of 25 804 patients were analyzed (derivation cohort, n=17 743; validation cohort, n=8061). The rhythm change event rate was 4.1% (724/17 743) in the derivation cohort, and 4.0% (326/8061) in the validation cohorts. Age, sex, presence of a witness, initial rhythm, chest compression by a bystander, shock with an automated external defibrillator by a bystander, and cause of the cardiac arrest were all found to be independently associated with spontaneous rhythm change before hospital arrival. Based on this finding, we developed and validated the Rhythm Change Before Hospital Arrival for Nonshockable score. The Harrell’s concordance index values of the score were 0.71 and 0.67 in the internal and external validations, respectively.

Conclusions

Seven factors were identified as predictors of a spontaneous rhythm change from nonshockable to shockable before hospital arrival. We developed and validated a score to predict rhythm change before hospital arrival.

Hydrogen gas with extracorporeal cardiopulmonary resuscitation improves survival after prolonged cardiac arrest in rats

BACKGROUND

Despite the benefits of extracorporeal cardiopulmonary resuscitation (ECPR) in cohorts of selected patients with cardiac arrest (CA), extracorporeal membrane oxygenation (ECMO) includes an artificial oxygenation membrane and circuits that contact the circulating blood and induce excessive oxidative stress and inflammatory responses, resulting in coagulopathy and endothelial cell damage. There is currently no pharmacological treatment that has been proven to improve outcomes after CA/ECPR. We aimed to test the hypothesis that administration of hydrogen gas (H₂) combined with ECPR could improve outcomes after CA/ECPR in rats.

METHODS

Rats were subjected to 20 min of asphyxial CA and were resuscitated by ECPR. Mechanical ventilation (MV) was initiated at the beginning of ECPR. Animals were randomly assigned to the placebo or H₂ gas treatment groups. The supplement gas was administered with O₂ through the ECMO membrane and MV. Survival time, electroencephalography (EEG), brain functional status, and brain tissue oxygenation were measured. Changes in the plasma levels of syndecan-1 (a marker of endothelial damage), multiple cytokines, chemokines, and metabolites were also evaluated.

RESULTS

The survival rate at 4 h was 77.8% (7 out of 9) in the H₂ group and 22.2% (2 out of 9) in the placebo group. The Kaplan-Meier analysis showed that H₂ significantly improved the 4 h-survival endpoint (log-rank P = 0.025 vs. placebo). All animals treated with H₂ regained EEG activity, whereas no recovery was observed in animals treated with placebo. H₂ therapy markedly improved intra-resuscitation brain tissue oxygenation and prevented an increase in central venous pressure after ECPR. H₂ attenuated an increase in syndecan-1 levels and enhanced an increase in interleukin-10, vascular endothelial growth factor, and leptin levels after ECPR. Metabolomics analysis identified significant changes at 2 h after CA/ECPR between the two groups, particularly in D-glutamine and D-glutamate metabolism.

CONCLUSIONS

H₂ therapy improved mortality in highly lethal CA rats rescued by ECPR and helped recover brain electrical activity. The underlying mechanism might be linked to protective effects against endothelial damage. Further studies are warranted to elucidate the mechanisms responsible for the beneficial effects of H₂ on ischemia-reperfusion injury in critically ill patients who require ECMO support.

Intubated COVID-19 predictive (ICOP) score for early mortality after intubation in patients with COVID-19

Patients with coronavirus disease 2019 (COVID-19) can have increased risk of mortality shortly after intubation. The aim of this study is to develop a model using predictors of early mortality after intubation from COVID-19. A retrospective study of 1945 intubated patients with COVID-19 admitted to 12 Northwell hospitals in the greater New York City area was performed. Logistic regression model using backward selection was applied. This study evaluated predictors of 14-day mortality after intubation for COVID-19 patients. The predictors of mortality within 14 days after intubation included older age, history of chronic kidney disease, lower mean arterial pressure or increased dose of required vasopressors, higher urea nitrogen level, higher ferritin, higher oxygen index, and abnormal pH levels. We developed and externally validated an intubated COVID-19 predictive score (ICOP). The area under the receiver operating characteristic curve was 0.75 (95% CI 0.73–0.78) in the derivation cohort and 0.71 (95% CI 0.67–0.75) in the validation cohort; both were significantly greater than corresponding values for sequential organ failure assessment (SOFA) or CURB-65 scores. The externally validated predictive score may help clinicians estimate early mortality risk after intubation and provide guidance for deciding the most effective patient therapies.

The rCAST score is useful for estimating the neurological prognosis in pediatric patients with post-cardiac arrest syndrome before ICU admission: External validation study using a nationwide prospective registry

INTRODUCTION

The objective of this cohort study was to investigate whether the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia score (rCAST), which we previously developed as a prognostic score for adult patients with post-cardiac arrest syndrome (PCAS), is also applicable to pediatric patients.

METHODS

Pediatric PCAS patients were included from an out-of-hospital cardiac arrest (OHCA) registry of the Japanese Association for Acute Medicine (JAAM). We validated the predictive accuracy of the rCAST for the neurological outcomes at 30 and 90 days. We also evaluated the probability of a good neurological outcome in each of the three specified severity categories based on the rCAST (low severity: ≤5.5; moderate severity: 6.0-14.0; high severity: ≥14.5).

RESULTS

Among the 737 pediatric patients with OHCA, the data of 179 pediatric PCAS patients in whom return of spontaneous circulation was achieved were analyzed. The areas under the curve (AUC) of the rCAST for predicting the neurological outcomes at 30 days and 90 days were 0.95 (95% CI: 0.90-0.99) and 0.96 (0.91-1.00), respectively. The proportions of patients with a good neurological outcome at 30 days were 100% (12/12) in the low severity group, 36.1% (13/36) in the moderate severity group, and 2.3% (3/131) in the high severity group.

CONCLUSIONS

The AUC of the rCAST for pediatric PCAS patients was found to be greater than 0.9 in the external validation, which corresponds to excellent predictive accuracy. There was no patient with good neurological outcome among the patients with more than 17.0 points (extremely high severity group).

Sequential Use of Romiplostim after Eltrombopag for Refractory Thrombocytopenia in Hydrocarbon-Induced Myelodysplasia

We describe the clinical course of a 65-year-old male patient who suffered from hydrocarbon-induced myelodysplasia and was successfully treated with the thrombopoietin receptor agonist (TPO-RA), romiplostim. Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, cytopenias, and increased risk of leukemic transformation. Here, we present a clinical vignette of MDS-associated thrombocytopenia refractory to first-line drugs as well as the TPO-RA, eltrombopag. To date, romiplostim is an U.S. Food and Drug Administration (FDA)-approved drug for idiopathic thrombocytopenic purpura and thrombocytopenia secondary to liver disease. Of note, currently the FDA advises against its use in MDS based on previous long-term safety concerns. Since the therapeutic options for thrombocytopenia in MDS patients are sparse, repurposing and reassessing romiplostim in this setting have been the focus of recent studies. At the time of writing, no published double-blind randomized clinical trials have conducted a head-to-head comparison between romiplostim and eltrombopag in thrombocytopenic MDS patients. To the best of our knowledge, for a thrombocytopenic patient in the setting of MDS, this is the first documented report of refractory clinical response after a 2-year use of eltrombopag in which replacement of treatment with romiplostim resulted in sustained physiological counts of thrombocytes within four weeks.

Understanding physiologic phospholipid maintenance in the context of brain mitochondrial phospholipid alterations after cardiac arrest

Cardiac arrest (CA) induces whole-body ischemia resulting in mitochondrial dysfunction. We used isolated mitochondria to examine phospholipid alterations in the brain, heart, kidney, and liver post-CA. Our data shows that ischemia/reperfusion most significantly alters brain mitochondria phospholipids, predominately after resuscitation. Furthermore, the alterations do not appear to be a function of dysregulated importation of phospholipids, but caused by impaired intra-mitochondrial synthesis and/or remodeling of phospholipids. Our data demonstrates only brain mitochondria undergo significant alterations in phospholipids, providing a rationale for the high vulnerability of the brain to ischemia/reperfusion. Furthermore, analyzing this pathophysiologic state provides insight into physiologic mitochondrial phospholipid metabolism.

Right Ventricle Embolization of IVC Filter Fragments: An Incidental Finding

This case report describes a 52-year-old male patient, with the incidental finding of inferior vena cava filter (IVCF) fragments impacted into the right ventricle, secondary to IVCF fragmentation and subsequent embolization. While IVCFs are prescribed to prevent pulmonary embolizations when anticoagulation is either contraindicated, or has failed, IVCF embolizations to the heart represent an extremely rare, but potentially life-threatening complication. Of note, at the time of writing, the utility and effectiveness of IVCF are not fully established. Intracardiac embolizations of IVCF typically present with complications such as hypotension, cardiac tamponade, arrhythmias, ventricle perforation, bleeding, cardiac arrest, and death. To our knowledge, this is the first case report of an asymptomatic kidney transplant recipient found to have right ventricle embolizations of IVCF fragments through routine assessment. Additionally, this is also the first report of an asymptomatic patient who presented IVCF fragments embolized to the right ventricle and left gonadal vein in the same clinical setting.

Pneumatosis Intestinalis in the Setting of COVID-19: A Single Center Case Series From New York

This case series reviews four critically ill patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [coronavirus disease 2019 (COVID-19)] suffering from pneumatosis intestinalis (PI) during their hospital admission. All patients received the biological agent tocilizumab (TCZ), an interleukin (IL)-6 antagonist, as an experimental treatment for COVID-19 before developing PI. COVID-19 and TCZ have been independently linked to PI risk, yet the cause of this relationship is unknown and under speculation. PI is a rare condition, defined as the presence of gas in the intestinal wall, and although its pathogenesis is poorly understood, intestinal ischemia is one of its causative agents. Based on COVID-19's association with vasculopathic and ischemic insults, and IL-6's protective role in intestinal epithelial ischemia-reperfusion injury, an adverse synergistic association of COVID-19 and TCZ can be proposed in the setting of PI. To our knowledge, this is the first published, single center, case series of pneumatosis intestinalis in COVID-19 patients who received tocilizumab therapy.

The interplay between bystander cardiopulmonary resuscitation and ambient temperature on neurological outcome after cardiac arrest: A nationwide observational cohort study

BACKGROUND

At lower ambient temperature, patients with out-of-hospital cardiac arrest (OHCA) easily experience hypothermia. Hypothermia has shown to improve the rate of successful return of spontaneous circulation (ROSC) in animal models. We hypothesized that lower temperature affects the impact of bystander cardiopulmonary resuscitation (CPR) on the increased odds of a favorable neurological outcome post-OHCA.

METHODS

This study used information collected by the prospective, nationwide, Utstein registry to examine data from 352,689 adult patients who experienced OHCA from 2012 to 2016 in Japan. The primary outcome was a 1-month favorable neurological outcomes. Multivariable logistic regression analyses were conducted to test the impact of bystander CPR according to the temperature on the favorable outcome.

RESULTS

A total of 201,111 patients with OHCA were included in the complete case analysis. The lower temperature group had lower proportions of receiving bystander CPR (46.5 vs. 47.9%) and having favorable outcome (2.1 vs 2.8%) than those in the higher group. Multivariable analysis revealed that bystander CPR at lower temperatures was significantly associated with favorable outcomes (adjusted odds ratio, 1.22; 95% CI, 1.09-1.37), whereas bystander CPR at higher temperatures was not associated with favorable outcomes (1.02; 0.92-1.13). The nonlinear relationship using a spline curve in the multivariable model revealed that odds ratio of favorable neurological outcomes associated with bystander CPR increased as the temperature decreased.

CONCLUSION

Bystander CPR was associated with favorable neurological outcomes at lower temperatures. The odds of a favorable outcome associated with bystander CPR increased as the temperature decreased.

Mitochondrial transplantation therapy for ischemia reperfusion injury: a systematic review of animal and human studies

BACKGROUND

Mitochondria are essential organelles that provide energy for cellular functions, participate in cellular signaling and growth, and facilitate cell death. Based on their multifactorial roles, mitochondria are also critical in the progression of critical illnesses. Transplantation of mitochondria has been reported as a potential promising approach to treat critical illnesses, particularly ischemia reperfusion injury (IRI). However, a systematic review of the relevant literature has not been conducted to date. Here, we systematically reviewed the animal and human studies relevant to IRI to summarize the evidence for mitochondrial transplantation.

METHODS

We searched MEDLINE, the Cochrane library, and Embase and performed a systematic review of mitochondrial transplantation for IRI in both preclinical and clinical studies. We developed a search strategy using a combination of keywords and Medical Subject Heading/Emtree terms. Studies including cell-mediated transfer of mitochondria as a transfer method were excluded. Data were extracted to a tailored template, and data synthesis was descriptive because the data were not suitable for meta-analysis.

RESULTS

Overall, we identified 20 animal studies and two human studies. Among animal studies, 14 (70%) studies focused on either brain or heart IRI. Both autograft and allograft mitochondrial transplantation were used in 17 (85%) animal studies. The designs of the animal studies were heterogeneous in terms of the route of administration, timing of transplantation, and dosage used. Twelve (60%) studies were performed in a blinded manner. All animal studies reported that mitochondrial transplantation markedly mitigated IRI in the target tissues, but there was variation in biological biomarkers and pathological changes. The human studies were conducted with a single-arm, unblinded design, in which autologous mitochondrial transplantation was applied to pediatric patients who required extracorporeal membrane oxygenation (ECMO) for IRI-associated myocardial dysfunction after cardiac surgery.

CONCLUSION

The evidence gathered from our systematic review supports the potential beneficial effects of mitochondrial transplantation after IRI, but its clinical translation remains limited. Further investigations are thus required to explore the mechanisms of action and patient outcomes in critical settings after mitochondrial transplantation. Systematic review registration The study was registered at UMIN under the registration number UMIN000043347.

Failure of non-invasive respiratory support after 6 hours from initiation is associated with ICU mortality

A previous study has shown that late failure (> 48 hours) of high-flow nasal cannula (HFNC) was associated with intensive care unit (ICU) mortality. The aim of this study was to investigate whether failure of non-invasive respiratory support, including HFNC and non-invasive positive pressure ventilation (NPPV), was also associated with the risk of mortality even if it occurs in the earlier phase. We retrospectively analyzed 59 intubated patients for acute respiratory failure due to lung diseases between April 2014 and June 2018. We divided the patients into 2 groups according to the time from starting non-invasive ventilatory support until their intubation: ≤ 6 hours failure and > 6 hours failure group. We evaluated the differences in the ICU mortality between these two groups. The multivariate logistic regression analysis showed the highest mortality in the > 6 hours failure group as compared to the ≤ 6 hours failure group, with a statistically significant difference (p < 0.01). It was also associated with a statistically significant increased 30-day mortality and decreased ventilator weaning rate. The ICU mortality in patients with acute respiratory failure caused by lung diseases was increased if the time until failure of HFNC and NPPV was more than 6 hours.

High-flow nasal cannula therapy for acute respiratory failure in patients with interstitial pneumonia: a retrospective observational study

High-flow nasal cannula (HFNC) oxygen is a therapy that has demonstrated survival benefits in acute respiratory failure (ARF). However, the role of HFNC in ARF due to interstitial pneumonia (IP) is unknown. The aim of this study was to compare the effects of HFNC therapy and non-invasive positive pressure ventilation (NPPV) in ARF due to IP. This retrospective observational study included 32 patients with ARF due to IP who were treated with HFNC (n = 13) or NPPV (n = 19). The clinical characteristics, intubation rate and 30-day mortality were analyzed and compared between the HFNC group and the NPPV group. Predictors of 30-day mortality were evaluated using a logistic regression model. HFNC group showed higher mean arterial blood pressure (median 92 mmHg; HFNC group vs 74 mmHg; NPPV group) and lower APACHEII score (median 22; HFNC group vs 27; NPPV group) than NPPV group. There was no significant difference in the intubation rate at day 30 between the HFNC group and the NPPV group (8% vs 37%: p = 0.069); the mortality rate at 30 days was 23% and 63%, respectively. HFNC therapy was a significant determinant of 30-day mortality in univariate analysis, and was confirmed to be an independent significant determinant of 30-day mortality in multivariate analysis (odds ratio, 0.148; 95% confidence interval, 0.025–0.880; p = 0.036). Our findings suggest that HFNC therapy can be a possible option for respiratory management in ARF due to IP. The results observed here warrant further investigation of HFNC therapy in randomized control trials.

Effects of Post-Resuscitation Normoxic Therapy on Oxygen-Sensitive Oxidative Stress in a Rat Model of Cardiac Arrest

Background

Cardiac arrest (CA) can induce oxidative stress after resuscitation, which causes cellular and organ damage. We hypothesized that post‐resuscitation normoxic therapy would protect organs against oxidative stress and improve oxygen metabolism and survival. We tested the oxygen‐sensitive reactive oxygen species from mitochondria to determine the association with hyperoxia‐induced oxidative stress.

Methods and Results

Sprague–Dawley rats were subjected to 10‐minute asphyxia‐induced CA with a fraction of inspired O₂ of 0.3 or 1.0 (normoxia versus hyperoxia, respectively) after resuscitation. The survival rate at 48 hours was higher in the normoxia group than in the hyperoxia group (77% versus 28%, P<0.01), and normoxia gave a lower neurological deficit score (359±140 versus 452±85, P<0.05) and wet to dry weight ratio (4.6±0.4 versus 5.6±0.5, P<0.01). Oxidative stress was correlated with increased oxygen levels: normoxia resulted in a significant decrease in oxidative stress across multiple organs and lower oxygen consumption resulting in normalized respiratory quotient (0.81±0.05 versus 0.58±0.03, P<0.01). After CA, mitochondrial reactive oxygen species increased by ≈2‐fold under hyperoxia. Heme oxygenase expression was also oxygen‐sensitive, but it was paradoxically low in the lung after CA. In contrast, the HMGB‐1 (high mobility group box‐1) protein was not oxygen‐sensitive and was induced by CA.

Conclusions

Post‐resuscitation normoxic therapy attenuated the oxidative stress in multiple organs and improved post‐CA organ injury, oxygen metabolism, and survival. Additionally, post‐CA hyperoxia increased the mitochondrial reactive oxygen species and activated the antioxidation system.

The evaluation of pituitary damage associated with cardiac arrest: An experimental rodent model

The pituitary gland plays an important endocrinal role, however its damage after cardiac arrest (CA) has not been well elucidated. The aim of this study was to determine a pituitary gland damage induced by CA. Rats were subjected to 10-min asphyxia and cardiopulmonary resuscitation (CPR). Immunohistochemistry and ELISA assays were used to evaluate the pituitary damage and endocrine function. Samples were collected at pre-CA, and 30 and 120 min after cardio pulmonary resuscitation. Triphenyltetrazolium chloride (TTC) staining demonstrated the expansion of the pituitary damage over time. There was phenotypic validity between the pars distalis and nervosa. Both CT-proAVP (pars nervosa hormone) and GH/IGF-1 (pars distalis hormone) decreased over time, and a different expression pattern corresponding to the damaged areas was noted (CT-proAVP, 30.2 ± 6.2, 31.5 ± 5.9, and 16.3 ± 7.6 pg/mg protein, p < 0.01; GH/IGF-1, 2.63 ± 0.61, 0.62 ± 0.36, and 2.01 ± 0.41 ng/mg protein, p < 0.01 respectively). Similarly, the expression pattern between these hormones in the end-organ systems showed phenotypic validity. Plasma CT-proAVP (r = 0.771, p = 0.025) and IGF-1 (r = −0.775, p = 0.024) demonstrated a strong correlation with TTC staining area. Our data suggested that CA induces pathological and functional damage to the pituitary gland.

Assessment of Cerebral Blood Oxygenation by Near-Infrared Spectroscopy before and after Resuscitation in a Rat Asphyxia Cardiac Arrest Model

Clinical investigators have focused on the real-time evaluation of cerebral blood oxygenation (CBO) by near-infrared spectroscopy (NIRS) during cardiopulmonary resuscitation (CPR). A previous study showed that an abrupt increase of oxy-hemoglobin (Hb) level and tissue oxygenation index (TOI) was associated with the timing of return of spontaneous circulation (ROSC). However, it is not clear how TOI alters before and after CPR including a period of cardiac arrest (CA). Therefore, this study aimed to assess CBO with asphyxia CA and its association with CPR to ROSC in rats. Male Sprague-Dawley rats were used. We attached NIRS (NIRO-200NX, Hamamatsu Photonics, Japan) from the nasion to the upper cervical spine in rats. A ten-minute asphyxia was given to induce CA. After CA, mechanical ventilation was restarted, and manual CPR was performed. We examined the mean arterial pressure (MAP), end-tidal carbon dioxide (ETCO₂), and Oxy/Deoxy-Hb and TOI. Out of 14 rats, 11 obtained sustained ROSC. After the induction of asphyxia, a rapid drop of TOI was observed, followed by a subsequent increase of Oxy-Hb, Deoxy-Hb, and TOI with CPR. Recent CPR guidelines suggest the use of ETCO₂ during CPR since its abrupt increase is a reasonable indicator of ROSC. In this study, abrupt increases in MAP, ETCO₂, and TOI were observed at the time of ROSC. TOI can be an alternative to ETCO₂ for identifying ROSC after CA, and it also has the capability of monitoring CBO during and after CPR.

Plasma metabolomics supports the use of long-duration cardiac arrest rodent model to study human disease by demonstrating similar metabolic alterations

Cardiac arrest (CA) is a leading cause of death and there is a necessity for animal models that accurately represent human injury severity. We evaluated a rat model of severe CA injury by comparing plasma metabolic alterations to human patients. Plasma was obtained from adult human control and CA patients post-resuscitation, and from male Sprague–Dawley rats at baseline and after 20 min CA followed by 30 min cardiopulmonary bypass resuscitation. An untargeted metabolomics evaluation using UPLC-QTOF-MS/MS was performed for plasma metabolome comparison. Here we show the metabolic commonality between humans and our severe injury rat model, highlighting significant metabolic dysfunction as seen by similar alterations in (1) TCA cycle metabolites, (2) tryptophan and kynurenic acid metabolites, and (3) acylcarnitine, fatty acid, and phospholipid metabolites. With substantial interspecies metabolic similarity in post-resuscitation plasma, our long duration CA rat model metabolically replicates human disease and is a suitable model for translational CA research.

Variable Selection for Nonparametric Learning with Power Series Kernels

In this letter, we propose a variable selection method for general nonparametric kernel-based estimation. The proposed method consists of two-stage estimation: (1) construct a consistent estimator of the target function, and (2) approximate the estimator using a few variables by ℓ1-type penalized estimation. We see that the proposed method can be applied to various kernel nonparametric estimation such as kernel ridge regression, kernel-based density, and density-ratio estimation. We prove that the proposed method has the property of variable selection consistency when the power series kernel is used. Here, the power series kernel is a certain class of kernels containing polynomial and exponential kernels. This result is regarded as an extension of the variable selection consistency for the nonnegative garrote (NNG), a special case of the adaptive Lasso, to the kernel-based estimators. Several experiments, including simulation studies and real data applications, show the effectiveness of the proposed method.

Challenges and Inconsistencies in Using Lysophosphatidic Acid as a Biomarker for Ovarian Cancer

Increased detection of plasma lysophosphatidic acid (LPA) has been proposed as a potential diagnostic biomarker in ovarian cancer, but inconsistency exists in these reports. It has been shown that LPA can undergo an artificial increase during sample processing and analysis, which has not been accounted for in ovarian cancer research. The aim of this study is to provide a potential explanation about how the artificial increase in LPA may have interfered with previous LPA analysis in ovarian cancer research. Using an established LC-MS method, we measured LPA and other lysophospholipid levels in plasma obtained from three cohorts of patients: non-cancer controls, patients with benign ovarian tumors, and those with ovarian cancer. We did not find the LPA level to be higher in cancer samples. To understand this inconsistency, we observed that LPA content changed more significantly than other lysophospholipids as a function of plasma storage time while frozen. Additionally, only LPA was found to be adversely impacted by incubation time depending on the Ethylenediaminetetraacetic acid (EDTA) concentration used during blood drawing. We also show that the inhibition of autotaxin effectively prevented artificial LPA generation during incubation at room temperature. Our data suggests that the artificial changes in LPA content may contribute to the discrepancies reported in literature. Any future studies planning to measure plasma LPA should carefully design the study protocol to consider these confounding factors.

Timing of administration of epinephrine predicts the responsiveness to epinephrine in norepinephrine-refractory septic shock: a retrospective study

Background

Currently, the appropriate method of management of patients with refractory septic shock remains unclear. This study aimed to evaluate the factors associated with response to epinephrine in norepinephrine-refractory septic shock.

Methods

A retrospective single-center observational study was performed using data from adult patients (≥ 18 years old) admitted to our emergency and medical intensive care unit (ICU) from January 2014 to December 2017 who had received epinephrine to treat norepinephrine-refractory septic shock. The response was considered positive if there was increase in mean arterial pressure of 10 mmHg or decrease in arterial lactate level 3 h after epinephrine administration.

Results

Forty-one patients were included: 24 responders (59%) and 17 non-responders (41%). Responders showed higher rate of survival from shock (92% vs. 18%; P < 0.001), and 28-day survival (83% vs. 18%; P < 0.001). In multivariable analysis, time of epinephrine administration after ICU admission (odds ratio [OR] 0.48; 95% confidence interval [CI] 0.27–0.87; P = 0.011) and SOFA score (OR 0.19; 95% CI 0.04–0.88; P = 0.034) were associated with epinephrine response. Time of epinephrine administration was also significantly associated with survival from shock (OR 0.42; P = 0.005) and 28-day survival (OR 0.14; P = 0.006), while SOFA score did not. Using inverse probability of treatment weighing (IPTW) adjustment of propensity score, epinephrine administration later than 24 h after ICU admission was associated with poor response (OR 0.07; 95% CI 0.02–0.21; P < 0.001).

Conclusions

Early administration of epinephrine after ICU admission (i.e., within 24 h) is associated with better hemodynamic status in patients with refractory septic shock.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0377-1) contains supplementary material, which is available to authorized users.

Accuracy of the first interpretation of early brain CT images for predicting the prognosis of post-cardiac arrest syndrome patients at the emergency department

Background

Early brain CT is one of the most useful tools for estimating the prognosis in patients with post-cardiac arrest syndrome (PCAS) at the emergency department (ED). The aim of this study was to evaluate the prognosis-prediction accuracy of the emergency physicians' interpretation of the findings on early brain CT in PCAS patients treated by targeted temperature management (TTM).

Methods

This was a double-center, retrospective, observational study. Eligible subjects were cardiac arrest patients admitted to the intensive care unit (ICU) for TTM between April 2011 and March 2017. We performed the McNemar test to compare the predictive accuracies of the interpretation by emergency physicians and radiologists and calculated the kappa statistic for determining the concordance rate between the interpretations by these two groups.

Results

Of the 122 eligible patients, 106 met the inclusion criteria for this study. The predictive accuracies (sensitivity, specificity) of the interpretations by the emergency physicians and radiologists were (0.34, 1.00) and (0.41, 0.93), respectively, with no significant difference in either the sensitivity or specificity as assessed by the McNemar test. The kappa statistic calculated to determine the concordance between the two interpretations was 0.66 (0.48-0.83), which showed a good conformity.

Conclusions

The emergency physicians' interpretation of the early brain CT findings in PCAS patients treated by TTM was as reliable as that of radiologists, in terms of prediction of the prognosis.

Differential effect of mild therapeutic hypothermia depending on the findings of hypoxic encephalopathy on early CT images in patients with post-cardiac arrest syndrome

INTRODUCTION

The aim of this study was to evaluate the differential effects of mild therapeutic hypothermia (MTH) in post-cardiac arrest syndrome (PCAS) patients depending on the presence/absence of hypoxic encephalopathy (HE) in the early brain CT images obtained before the initiation of MTH.

METHODS

We conducted a retrospective review of the data of a total of 129 patients with PCAS who were treated by MTH (34 °C) or normothermia treatment (NT) (35 °C or 36 °C), and had undergone brain CT examination prior to the initiation of these treatments. We divided the subjects into 4 groups, namely, the HE(-)/MTH, HE(-)/NT, HE(+)/MTH, and HE(+)/NT groups, for evaluating the interaction effect between the two variables. Then, we compared the neurological outcomes between the HE(-)/MTH and HE(-)/NT groups by multivariate logistic analysis. Good outcome was defined as a Cerebral Performance Category score of ≤2 at 30 days.

RESULTS

The percentages of subjects with a good outcome in the HE(-)/MTH and HE(-)/NT group were 68.9% (42/61) and 36.1% (13/36), respectively (p = .003), while those in the HE(+)/MTH and HE(+)/NT groups were lower, at 7.4% (2/27) and 20.0% (1/5), respectively (p = .410), suggesting a statistically significant interaction effect between the two variables (p_interaction = 0.002). In the HE(-) group, MTH was associated with a higher odds ratio of a good outcome as compared to NT (OR 6.80, 95% CI 1.19-38.96, p = .031).

CONCLUSIONS

The effect of MTH in patients with PCAS differed depending on the presence/absence of evidence of HE on the early CT images.

The safety of a novel early mobilization protocol conducted by ICU physicians: a prospective observational study

BACKGROUND

There are numerous barriers to early mobilization (EM) in a resource-limited intensive care unit (ICU) without a specialized team or an EM culture, regarding patient stability while critically ill or in the presence of medical devices. We hypothesized that ICU physicians can overcome these barriers. The aim of this study was to investigate the safety of EM according to the Maebashi EM protocol conducted by ICU physicians.

METHODS

This was a single-center prospective observational study. All consecutive patients with an unplanned emergency admission were included in this study, according to the exclusion criteria. The observation period was from June 2015 to June 2016. Data regarding adverse events, medical devices in place during rehabilitation, protocol adherence, and rehabilitation outcomes were collected. The primary outcome was safety.

RESULTS

A total of 232 consecutively enrolled patients underwent 587 rehabilitation sessions. Thirteen adverse events occurred (2.2%; 95% confidence interval, 1.2-3.8%) and no specific treatment was needed. There were no instances of dislodgement or obstruction of medical devices, tubes, or lines. The incidence of adverse events associated with mechanical ventilation or extracorporeal membrane oxygenation (ECMO) was 2.4 and 3.6%, respectively. Of 587 sessions, 387 (66%) sessions were performed at the active rehabilitation level, including sitting out of the bed, active transfer to a chair, standing, marching, and ambulating. ICU physicians attended over 95% of these active rehabilitation sessions. Of all patients, 143 (62%) got out of bed within 2 days (median 1.2 days; interquartile range 0.1-2.0).

CONCLUSIONS

EM according to the Maebashi EM protocol conducted by ICU physicians, without a specialized team or EM culture, was performed at a level of safety similar to previous studies performed by specialized teams, even with medical devices in place, including mechanical ventilation or ECMO. Protocolized EM led by ICU physicians can be initiated in the acute phase of critical illness without serious adverse events requiring additional treatment.

A novel scoring system for predicting the neurologic prognosis prior to the initiation of induced hypothermia in cases of post-cardiac arrest syndrome: the CAST score

BACKGROUND

The aim of this study was to develop a scoring system for identifying the post-cardiac arrest syndrome (PCAS) patients with a good potential for recovery prior to the initiation of induced therapeutic hypothermia.

METHODS

A multi-center, retrospective, observational study was performed. Data of a total of 151 consecutive adults who underwent induced hypothermia after cardiac arrest (77 learning cases from two hospitals and 74 validation cases from two other hospitals) were analyzed.

RESULTS

In the learning set, 8 factors (initial rhythm, witnessed status and time until return of spontaneous circulation, pH, serum lactate, motor score according to the Glasgow Coma Scale (GCS), gray matter attenuation to white matter attenuation ratio (GWR), serum albumin, and hemoglobin) were found to be strongly correlated with the neurological outcomes. A tentative scoring system was created from the learning data using these factors, and the predictive accuracy (sensitivity and specificity) was evaluated in terms of both internal validation (0.85 and 0.84) and external validation (cutoff 50%: 0.95 and 0.90, 30%: 0.87 and 0.98, 15%: 0.67 and 1.00). Finally, using all the data, we established a post-Cardiac Arrest Syndrome for induced Therapeutic hypothermia (CAST) score to predict the neurologic prognosis prior to initiation of induced hypothermia.

CONCLUSIONS

The CAST score was developed to predict the neurological outcomes of PCAS patients treated by induced hypothermia. The likelihood of good recovery at 30 days was extremely low in PCAS patients with a CAST score of ≤15%. Prospective validation of the score is needed in the future.

Ascorbate-induced high-affinity binding of copper to cytosolic proteins

Copper chaperones are necessary for intracellular trafficking of copper to target proteins. This is probably because the milieu inside the cell has a large capacity for sequestering this metal. By fluorometry using a fluorescent Cu(II) chelator and by centrifugal ultrafiltration, we have studied copper binding of the whole cytosolic proteins from mouse brain and liver, and found that their binding capacity and affinity for copper were markedly increased by ascorbate. Brain cytosolic protein bound, with high affinity, 63 nmol of copper/mg, more than half of which was redox-inactive, as indicated by its inability to catalyze oxidation of ascorbate. Most of the bound copper was in the Cu(I) state, coordinating to thiol groups of protein. Cytosolic protein competed for copper more strongly than GSH when compared at their relative concentrations in tissues. The results taken together suggest that protein thiols of cytosol can strongly sequester copper.

Impaired reductive regeneration of ascorbic acid in the Goto-Kakizaki diabetic rat

Ascorbic acid (AA) is a naturally occurring major antioxidant that is essential for the scavenging of toxic free radicals in both plasma and tissues. AA levels in plasma and tissues have been reported to be significantly lower than normal in diabetic animals and humans, and might contribute to the complications found at the late stages of diabetes. In this study, plasma and hepatic AA levels and AA regeneration were studied in the Goto-Kakizaki diabetic rat (GK rat) to elucidate the mechanism of decreasing plasma and hepatic AA levels in diabetes. AA concentrations in the plasma and liver were significantly lower in GK than in control rats. AA levels in primary cultured hepatocytes derived from GK rats were lower than those derived from control Wistar rats with or without dehydroascorbic acid (DHA) in the medium. Among various enzyme activities that reduce DHA to AA, the NADPH-dependent regeneration of AA in the liver was significantly suppressed in GK rats. Northern blot analysis revealed that only the expression of 3-alpha-hydroxysteroid dehydrogenase (AKR) was significantly suppressed in these rats. These results suggest that decreased AA-regenerating activity, probably through decreased expression of AKR, contributes to the decreased AA levels and increased oxidative stress in GK rats.

Copper-catalyzed autoxidations of GSH and L-ascorbic acid: mutual inhibition of the respective oxidations by their coexistence

Glutathione (GSH) is known to inhibit copper-catalyzed autoxidation of L-ascorbic acid (AA); in this study, AA was found to conversely inhibit copper-catalyzed autoxidation of GSH. To elucidate the mechanism of the mutual inhibition of the autoxidations of these two reducing substances in their coexistence, we have kinetically investigated these phenomena. The study of the former phenomenon revealed that GSH forms a 1:1 chelate with Cu(+) and thereby prevents the autoxidation of AA. By the analysis of the latter phenomenon, it was postulated that the inhibition of GSH oxidation by AA is due to rapid reduction of thiyl radical of GSH by AA rather than competition of AA with GSH in the reduction of Cu(2+). The effect of GSH on the formation of hydroxyl radical by the copper-catalyzed autoxidation of AA was also studied and it was found that the hydroxyl radical formation was delayed dose-dependently by GSH with time lags comparable to those of the oxidation of AA. Because there are several lines of evidence that redox-active copper ions are released from tissues under pathological conditions, it is possible that such copper ions coexist with AA and GSH in vivo, and in such a situation, GSH may exert an inhibitory effect on the hydroxyl radical formation caused by the autoxidation of AA.