Targeted temperature management for adult out-of-hospital cardiac arrest: current concepts and clinical applications

The effects of ECMO on neurological function recovery of critical patients: A double-edged sword

Extracorporeal membrane oxygenation (ECMO) played an important role in the treatment of patients with critical care such as cardiac arrest (CA) and acute respiratory distress syndrome. ECMO is gradually showing its advantages in terms of speed and effectiveness of circulatory support, as it provides adequate cerebral blood flow (CBF) to the patient and ensures the perfusion of organs. ECMO enhances patient survival and improves their neurological prognosis. However, ECMO-related brain complications are also important because of the high risk of death and the associated poor outcomes. We summarized the reported complications related to ECMO for patients with CA, such as north–south syndrome, hypoxic–ischemic brain injury, cerebral ischemia–reperfusion injury, impaired intracranial vascular autoregulation, embolic stroke, intracranial hemorrhage, and brain death. The exact mechanism of ECMO on the role of brain function is unclear. Here we review the pathophysiological mechanisms associated with ECMO in the protection of neurologic function in recent years, as well as the ECMO-related complications in brain and the means to improve it, to provide ideas for the treatment of brain function protection in CA patients.

Reliability of prognostic biomarkers after prehospital extracorporeal cardiopulmonary resuscitation with target temperature management

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) performed at the emergency scene in out-of-hospital cardiac arrest (OHCA) can minimize low-flow time. Target temperature management (TTM) after cardiac arrest can improve neurological outcome. A combination of ECPR and TTM, both implemented as soon as possible on scene, appears to have promising results in OHCA. To date, it is still unknown whether the implementation of TTM and ECPR on scene affects the time course and value of neurological biomarkers.

Methods

69 ECPR patients were examined in this study. Blood samples were collected between 1 and 72 h after ECPR and analyzed for S100, neuron-specific enolase (NSE), lactate, D-dimers and interleukin 6 (IL6). Cerebral performance category (CPC) scores were used to assess neurological outcome after ECPR upon hospital discharge. Resuscitation data were extracted from the Regensburg extracorporeal membrane oxygenation database and all data were analyzed by a statistician. The data were analyzed using non-parametric methods. Diagnostic accuracy of biomarkers was determined by area under the curve (AUC) analysis. Results were compared to the relevant literature.

Results

Non-hypoxic origin of cardiac arrest, manual chest compression until ECPR, a short low-flow time until ECPR initiation, low body mass index (BMI) and only a minimal need of extra-corporeal membrane oxygenation support were associated with a good neurological outcome after ECPR. Survivors with good neurological outcome had significantly lower lactate, IL6, D-dimer, and NSE values and demonstrated a rapid decrease in the initial S100 value compared to non-survivors.

Conclusions

A short low-flow time until ECPR initiation is important for a good neurological outcome. Hypoxia-induced cardiac arrest has a high mortality rate even when ECPR and TTM are performed at the emergency scene. ECPR patients with a higher BMI had a worse neurological outcome than patients with a normal BMI. The prognostic biomarkers S100, NSE, lactate, D-dimers and IL6 were reliable indicators of neurological outcome when ECPR and TTM were performed at the emergency scene.

Association between rewarming duration and neurological outcome in out-of-hospital cardiac arrest patients receiving therapeutic hypothermia

AIM

The European Resuscitation Council guidelines recommend a slow rate of rewarming of 0.25 °C/h-0.5 °C/h for out-of-hospital cardiac arrest (OHCA) patients receiving therapeutic hypothermia (TH). Conversely, a very slow rewarming of 1 °C/day is generally applied in Japan. The rewarming duration ranged from less than 24 h up to more than 50 h. No randomized control trials have examined the optimal rewarming speed for TH in OHCA patients. Therefore, we examined the association between the rewarming duration and neurological outcomes in OHCA patients who received TH.

METHODS

This study was a secondary analysis of the Japanese Population-based Utstein-style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia (J-PULSE-HYPO) study registry, a multicenter prospective cohort study. Patients suffering from OHCA who received TH (target temperature, 34 °C) after the return of spontaneous circulation from 2005 to 2011 in 14 hospitals throughout Japan were enrolled. The rewarming duration was defined as the time from the beginning of rewarming at a target temperature of 34 °C until reaching 36 °C. The primary outcome was an unfavorable neurological outcome at hospital discharge, i.e., a cerebral performance category of 3-5.

RESULTS

The J-PULSE-HYPO study enrolled 452 OHCA patients. Of these, 328 were analyzed; 79.9% survived to hospital discharge, of which 56.4% had a favorable neurological outcome. Multivariable logistic regression analysis revealed that the rewarming duration was independently associated with unfavorable neurological outcomes [odds ratio (per 5 h), 0.89; 95% confidence interval, 0.79-0.99; p =  0.032].

CONCLUSION

A longer rewarming duration was significantly associated with and was an independent predictor of favorable neurological outcomes in OHCA patients who received TH.

The complement lectin pathway after cardiac arrest

The lectin pathway (LP) of the complement system may initiate inflammatory reactions when body tissue is altered. We aimed to investigate the levels of the LP proteins in out-of-hospital cardiac arrest patients, and to compare these with healthy individuals. Furthermore, we aimed to clarify whether the duration of targeted temperature management influenced LP protein levels, and we further examined whether LP proteins were associated with 30-day mortality. We included 82 patients resuscitated from out-of-hospital cardiac arrest. The patients were randomly assigned to 24 or 48 hours of targeted temperature management at 33 ± 1°C. Blood samples were obtained 22, 46 and 70 hours after target temperature was reached. Levels of the LP proteins (mannan-binding lectin [MBL], M-ficolin, H-ficolin, collectin liver 1 [CL-L1], MBL-associated serine protease 1 [MASP-1], MASP-2, MASP-3 and MBL-associated protein of 44 kDa [MAp44]) were measured using time-resolved immunofluorometric assays. Data from 82 gender matched healthy individuals were used for comparison. Levels of CL-L1, MASP-1, MASP-2 and MAp44 were significantly higher, whereas M-ficolin levels were significantly lower in cardiac arrest patients compared with healthy individuals. MASP-2, MASP-3 and M-ficolin levels changed significantly when comparing 24 and 48 hours of targeted temperature management. The LP protein levels were not different between 30-day survivors and non-survivors after cardiac arrest. The differences in LP protein levels between patients and healthy individuals may indicate that cardiac arrest patients have an activated LP. Overall, the LP protein levels were not influenced by the duration of targeted temperature management, and the levels were not associated with 30-day mortality.

Targeted Temperature Management for Improved Outcomes: Are We There Yet?

Therapeutic hypothermia, also referred to as targeted temperature management, has been a component of the postcardiac arrest treatment guidelines since 2010. Although almost a decade has passed since its inclusion in the postarrest guidelines, many unanswered questions remain regarding selection of the appropriate patient population, optimal target temperature, ideal window of time in which to initiate therapy after arrest, most efficient, safe, and accurate equipment choice for inducing and maintaining hypothermia, most effective duration of treatment, and rate of cooling or rewarming. On a national and international level, critical care nurses are in a unique position to participate in research that will define targeted temperature management protocols and practices. Nurses are also ideal for standardizing the targeted temperature management policy and protocol locally and nationally based on current available evidence. This review aims to serve 2 purposes: first, to provide a broad update on the current clarifications and limitations per research findings on target temperature management therapy; second, to explain how critical care nurses can use this updated information to improve outcomes for their patients with cardiac arrest.

Hypothermia Used in Medical Applications for Brain and Spinal Cord Injury Patients

Despite more than 80 years of animal experiments and clinical practice, efficacy of hypothermia in improving treatment outcomes in patients suffering from cell and tissue damage caused by ischemia is still ongoing. This review will first describe the history of utilizing cooling in medical treatment, followed by chemical and biochemical mechanisms of cooling that can lead to neuroprotection often observed in animal studies and some clinical studies. The next sections will be focused on current cooling approaches/devices, as well as cooling parameters recommended by researchers and clinicians. Animal and clinical studies of implementing hypothermia to spinal cord and brain tissue injury patients are presented next. This section will review the latest outcomes of hypothermia in treating patients suffering from traumatic brain injury (TBI), spinal cord injury (SCI), stroke, cardiopulmonary surgery, and cardiac arrest, followed by a summary of available evidence regarding both demonstrated neuroprotection and potential risks of hypothermia. Contributions from bioengineers to the field of hypothermia in medical treatment will be discussed in the last section of this review. Overall, an accumulating body of clinical evidence along with several decades of animal research and mathematical simulations has documented that the efficacy of hypothermia is dependent on achieving a reduced temperature in the target tissue before or soon after the injury-precipitating event. Mild hypothermia with temperature reduction of several degrees Celsius is as effective as modest or deep hypothermia in providing therapeutic benefit without introducing collateral/systemic complications. It is widely demonstrated that the rewarming rate must be controlled to be lower than 0.5 °C/h to avoid mismatch between local blood perfusion and metabolism. In the past several decades, many different cooling methods and devices have been designed, tested, and used in medical treatments with mixed results. Accurately designing treatment protocols to achieve specific cooling outcomes requires collaboration among engineers, researchers, and clinicians. Although this problem is quite challenging, it presents a major opportunity for bioengineers to create methods and devices that quickly and safely produce hypothermia in targeted tissue regions without interfering with routine medical treatment.

Evolved role of the cardiovascular intensive care unit (CICU)

Cardiovascular intensive care refers to special systemic management for the patients with severe cardiovascular disease (CVD), which consists of heart disease and vascular disease. CVD is one of the leading causes of death in the world. In order to prevent death due to CVDs, an intensive care unit for severe CVD patients, so-called cardiovascular intensive care unit (CICU), has been developed in many general hospitals. The technological developments of clinical cardiology, such as invasive hemodynamic monitoring and intracoronary interventional procedures and devices, have resulted in evolution of intensive care for CVDs. Subsequently, severe CVD patients admitted to CICU are increasing year by year. Dedicated medical staff is required for CICU in order to perform best patient management. It is necessary for optimal patient care to select effective means from various hemodynamic tools and to adjust the usage according to the clinical situation such as cardiogenic shock and acute heart failure. Furthermore, the patients in the CICU often have various complications such as respiratory failure and renal failure. Therefore, medical staffs who work at CICU are required to have the ability to practice systemic intensive care.

PAIS 2 (Paracetamol [Acetaminophen] in Stroke 2): Results of a Randomized, Double-Blind Placebo-Controlled Clinical Trial

BACKGROUND AND PURPOSE

Subfebrile body temperature and fever in the first days after stroke are strongly associated with unfavorable outcome. A subgroup analysis of a previous trial suggested that early treatment with paracetamol may improve functional outcome in patients with acute stroke and a body temperature of ≥36.5°C. In the present trial, we aimed to confirm this finding.

METHODS

PAIS 2 (Paracetamol [Acetaminophen] in Stroke 2) was a multicenter, randomized, double-blind, placebo-controlled clinical trial. We aimed to include 1500 patients with acute ischemic stroke or intracerebral hemorrhage within 12 hours of symptom onset. Patients were treated with paracetamol in a daily dose of 6 g or matching placebo for 3 consecutive days. The primary outcome was functional outcome at 3 months, assessed with the modified Rankin Scale and analyzed with multivariable ordinal logistic regression. Because of slow recruitment and lack of funding, the study was stopped prematurely.

RESULTS

Between December 2011 and October 2015, we included 256 patients, of whom 136 (53%) were allocated to paracetamol. In this small sample, paracetamol had no effect on functional outcome (adjusted common odds ratio, 1.15; 95% confidence interval, 0.74-1.79). There was no difference in the number of serious adverse events (paracetamol n=35 [26%] versus placebo n=28 [24%]).

CONCLUSIONS

Treatment with high-dose paracetamol seemed to be safe. The effect of high-dose paracetamol on functional outcome remains uncertain. Therefore, a large trial of early treatment with high-dose paracetamol is still needed.

CLINICAL TRIAL REGISTRATION

URL: http://www.trialregister.nl. Unique identifier: NTR2365.