Efficacy of different cooling technologies for therapeutic temperature management: A prospective intervention study

Temperature management in acute brain injury: A narrative review

Temperature management has been used in patients with acute brain injury resulting from different conditions, such as post-cardiac arrest hypoxic-ischaemic insult, acute ischaemic stroke, and severe traumatic brain injury. However, current evidence offers inconsistent and often contradictory results regarding the clinical benefit of this therapeutic strategy on mortality and functional outcomes. Current guidelines have focused mainly on active prevention and treatment of fever, while therapeutic hypothermia (TH) has fallen into disuse, although doubts persist as to its effectiveness according to the method of application and appropriate patient selection. This narrative review presents the most relevant clinical evidence on the effects of TH in patients with acute neurological damage, and the pathophysiological concepts supporting its use.

Cooling Under a Blanketrol System Versus Cooling With an Arctic Sun Thermoregulation System (CATS) for Neonates Undergoing Therapeutic Hypothermia

Background Despite evidence suggesting improved outcomes in neonates with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH), data on the impact of temperature variability during cooling and its association with clinical outcomes remain limited. Objective To compare the efficacy and ease of use of two different cooling systems, the Arctic Sun (Medivance, Inc., Louisville, CO) vs. the Blanketrol III (Gentherm Medical, Cincinnati, OH) on achieving TH, temperature variability, and clinical outcomes in neonates with HIE undergoing TH. Methods This study was conducted at the Baylor Scott and White Medical Center's Level IV NICU. The study employed a retrospective cohort design, comparing infants treated with the Arctic Sun device (from December 2020 to August 2021) to a historical cohort treated with the Blanketrol system (from January 2017 to November 2020). Both groups were evaluated for clinical characteristics, patients' outcomes, and ease of use of the cooling devices. Ease of use was assessed through a self-developed survey administered to NICU nurses. Core body temperatures throughout the cooling course were documented at four-hour intervals, including induction, maintenance, and rewarming phases. Results Twenty-two infants were cooled using the Arctic Sun system, and 44 infants were cooled with the Blanketrol device. Median birth weight and gestational age were comparable. There were no significant differences in one-minute and five-minute appearance, pulse, grimace, activity, and respiration (APGAR) scores. The Arctic Sun group had a significantly higher rate of maternal morbidities, including diabetes and placental abruption. Although the median temperature achieved with both devices was 33.5°C, temperature variability was significantly greater with the Blanketrol device (p = 0.03). Thrombocytopenia rates were statistically different between the groups (9% in Arctic Sun vs. 38% in Blanketrol, p = 0.001). Although the Blanketrol group had higher rates of disseminated intravascular coagulation (48% vs. 37%), hypercalcemia (23% vs. 5%), and subcutaneous fat necrosis (7% vs. 5%), these differences were not statistically significant. A nurses' survey on ease of use revealed a strong preference for the Arctic Sun cooling system. Over 85% of nurses found it easier to learn and set up and required less manual intervention than the Blanketrol device. Conclusions Gel adhesive pad-based TH is a potentially superior modality to traditional water-circulating cooling devices. These pads offer advantages in user-friendliness, improved temperature control precision, and potentially reduced adverse event profiles.

A narrative review of intravascular catheters in therapeutic hypothermia

Therapeutic hypothermia (TH) has been regarded as a promising neuroprotective method for acute ischemic stroke (AIS) for decades. During the development of TH, most researchers focused on improving hypothermic benefits by optimizing treatment processes and conditions. Intravenous thrombolysis and endovascular thrombectomy, for instance, have been introduced into AIS treatment. However, the lack of specialized intervention consumables, especially intervention catheter, led to inaccurate and uncontrolled hypothermic temperature, limited the efficacy of TH. In this review, intervention catheters as well as accessory equipment utilized in TH treatment has been summarized. Hopefully, this review may inspire the future development of TH specialized intervention catheter, enhance the outcome of TH, and neuroprotective efficacy in AIS.

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

A Commentary on the Effect of Targeted Temperature Management in Patients Resuscitated from Cardiac Arrest

The members of the International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force have written a comprehensive summary of trials of the effectiveness of induced hypothermia (IH) or targeted temperature management (TTM) in comatose patients after cardiac arrest (CA). However, in-depth analysis of these studies is incomplete, especially since there was no significant difference in primary outcome between hypothermia versus normothermia in the recently reported TTM2 trial. We critically appraise trials of IH/TTM versus normothermia to characterize reasons for the lack of treatment effect, based on a previously published framework for what to consider when the primary outcome fails. We found a strong biologic rationale and external clinical evidence that IH treatment is beneficial. Recent TTM trials mainly included unselected patients with a high rate of bystander cardiopulmonary resuscitation. The treatment was not applied as intended, which led to a large delay in achievement of target temperature. While receiving intensive care, sedative drugs were likely used that might have led to increased neurologic damage as were antiplatelet drugs that could be associated with increased acute stent thrombosis in hypothermic patients. It is reasonable to still use or evaluate IH treatment in patients who are comatose after CA as there are multiple plausible reasons why IH compared to normothermia did not significantly improve neurologic outcome in the TTM trials.

Efficacy and safety of the Arctic Sun device for hypoxic-ischemic encephalopathy in adult patients following cardiopulmonary resuscitation: A systematic review and meta-analysis

AIM

The principal objective of this study was to carry out a comprehensive and thorough analysis to compare the safety and effectiveness of the Arctic Sun, a servo-controlled surface cooling device, with conventional cooling techniques for providing therapeutic hypothermia in adult patients who had experienced hypoxic-ischemic brain injury following cardiopulmonary resuscitation.

METHODS

In order to achieve our goal, we conducted an extensive search of multiple databases including PubMed, Embase, Cochrane, and ClinicalTrials.gov up to the date of July 30, 2021. We only included studies that compared the safety and efficacy of the Arctic Sun surface cooling equipment with standard cooling approaches such as cooling blankets, ice packs, and intravenous cold saline for treating comatose adult patients who had recovered after experiencing cardiac arrest. We evaluated various outcomes, including all-cause mortality, good neurological outcome at 1 month, and the occurrence of adverse effects such as infections, shock, and bleeding. We employed a random-effects meta-analysis to estimate the odds ratio (OR) with 95% confidence intervals (CIs) for dichotomous outcomes.

RESULTS

One hundred and fourteen records were identified through our search; however, only three studies met our eligibility criteria, resulting in overall 187 patients incorporated in the meta-analysis. The findings indicated no significant difference in mortality rates among the Arctic Sun device and conventional cooling techniques (OR: 0.64; 95% CI: 0.34-1.19; P = 0.16; I2 = 0%). In addition, we found no significant difference in occurrence of good neurological outcomes (OR: 1.74; 95% CI: 0.94-3.25; P = 0.08; I2 = 0%) between the two cooling methods. However, the application of the Arctic Sun device was associated with increased incidence of infections compared to standard cooling methods (OR: 2.46; 95% CI: 1.18-5.11; P = 0.02; I2 = 0%). While no significant difference occurred in the incidence of shock (OR: 0.29; 95% CI: 0.07-1.18; P = 0.08; I2 = 40%), the use of the Arctic Sun device was linked to significantly fewer bleeding complications compared to standard cooling methods (OR: 0.11; 95% CI: 0.02-0.79; P = 0.03; I2 = 0%).

CONCLUSIONS

After analyzing the results of our meta-analysis, we concluded that the use of the Arctic Sun device for targeted temperature management following cardiopulmonary resuscitation did not result in significant differences in mortality rates or improve neurological outcomes when compared to standard cooling techniques.

Optimal Timing of Targeted Temperature Management for Post-Cardiac Arrest Syndrome: Is Sooner Better?

Targeted temperature management (TTM) is often considered to improve post-cardiac arrest patients’ outcomes. However, the optimal timing to initiate cooling remained uncertain. This retrospective analysis enrolled all non-traumatic post-cardiac arrest adult patients with either out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrest (IHCA) who received TTM from July 2015 to July 2021 at our hospital. The values of time delay before TTM and time to target temperature were divided into three periods according to optimal cut-off values identified using receiver operating characteristic curve analysis. A total of 177 patients were enrolled. A shorter time delay before TTM (pre-induction time) was associated with a lower survival chance at 28 days (32.00% vs. 54.00%, p = 0.0279). Patients with a longer cooling induction time (>440 minis) had better neurological outcomes (1.58% vs. 1.05%; p = 0.001) and survival at 28 days (58.06% vs. 29.25%; p = 0.006). After COX regression analysis, the influence of pre-induction time on survival became insignificant, but patients who cooled slowest still had a better chance of survival at 28 days. In conclusion, a shorter delay before TTM was not associated with better clinical outcomes. However, patients who took longer to reach the target temperature had better hospital survival and neurological outcomes than those who were cooled more rapidly. A further prospective study was warranted to evaluate the appropriate time window of TTM.

Moderate systemic therapeutic hypothermia is insufficient to protect blood-spinal cord barrier in spinal cord injury

Blood–spinal cord barrier (BSCB) disruption is a pivotal event in spinal cord injury (SCI) that aggravates secondary injury but has no specific treatment. Previous reports have shown that systemic therapeutic hypothermia (TH) can protect the blood–brain barrier after brain injury. To verify whether a similar effect exists on the BSCB after SCI, moderate systemic TH at 32°C was induced for 4 h on the mice with contusion-SCI. In vivo two-photon microscopy was utilized to dynamically monitor the BSCB leakage 1 h after SCI, combined with immunohistochemistry to detect BSCB leakage at 1 and 4 h after SCI. The BSCB leakage was not different between the normothermia (NT) and TH groups at both the in vivo and postmortem levels. The expression of endothelial tight junctions was not significantly different between the NT and TH groups 4 h after SCI, as detected by capillary western blotting. The structural damage of the BSCB was examined with immunofluorescence, but the occurrence of junctional gaps was not changed by TH 4 h after SCI. Our results have shown that moderate systemic TH induced for 4 h does not have a protective effect on the disrupted BSCB in early SCI. This treatment method has a low value and is not recommended for BSCB disruption therapy in early SCI.

Cost-Effectiveness Analysis of Intravascular Targeted Temperature Management after Cardiac Arrest in England

BACKGROUND

Targeted temperature management (TTM) has been shown to improve neurological outcomes and survival in patients resuscitated from cardiac arrest; however, the cost effectiveness of multiple TTM methods is not well studied.

OBJECTIVE

This study aimed to evaluate the cost effectiveness of intravascular temperature management (IVTM) using Thermogard XP compared with surface cooling methods after cardiac arrest in the England from the perspectives of the UK national health service and Personal Social Services.

METHODS

We developed a multi-state Markov model that evaluated IVTM (Thermogard XP) compared with surface cooling using two different devices (Blanketrol III and Arctic Sun 5000) over a short-term and lifetime time horizon. Model input parameters were obtained from the literature and local databases. We assumed a hypothetical cohort of 1000 patients who required TTM after cardiac arrest per year in the England. The outcomes were costs (in £, year 2019 values) and quality-adjusted life-years (QALYs), discounted at 3.5% annually. Deterministic and probabilistic sensitivity analyses were undertaken to examine the effect of alternative assumptions and uncertainty in model parameters on the results.

RESULTS

The cost-effectiveness analysis determined that Thermogard XP resulted in direct cost savings of £2339 and £2925 (per patient) compared with Blanketrol III and Arctic Sun 5000, respectively, and a gain of 0.98 QALYs over the patient lifetime. The probabilistic sensitivity analysis demonstrated that the probability of Thermogard XP being cost saving would be 69.2% and 65.3% versus the Arctic Sun 5000 and Blanketrol III, respectively.

CONCLUSION

Implementation of IVTM using Thermogard XP can lead to cost savings and improved patient quality of life versus surface cooling methods.

Intravascular Versus Surface Cooling in Patients Resuscitated From Cardiac Arrest: A Systematic Review and Network Meta-Analysis With Focus on Temperature Feedback

OBJECTIVE

The aim of the study was to compare the effect of intravascular cooling (IC), surface cooling with temperature feedback (SCF), and surface cooling without temperature feedback (SCnoF) on neurologic outcome and survival in patients successfully resuscitated from cardiac arrest (CA) and treated with targeted temperature management (TTM) at 32-34°C.

DATA SOURCES

We performed a systematic review on Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, MEDLINE, SCOPUS, CINAHL, Web of Science, and Clinical Trials up to June 30, 2021.

STUDY SELECTION

We included randomized and nonrandomized studies on IC, SCF, and SCnoF in adult humans resuscitated from CA undergoing TTM, reporting neurologic outcome or survival.

DATA EXTRACTION

We performed a network meta-analysis to assess the comparative effects of IC, SCF, and SCnoF. The overall effect between two cooling methods included the effect of direct and indirect comparisons. Results are given as odds ratios (OR) and 95% CIs. Rankograms estimated the probability of TTM methods being ranked first, second, and third best interventions.

DATA SYNTHESIS

A total of 14 studies involving 4,062 patients met the inclusion criteria. Four studies were randomized controlled studies, and 10 studies were nonrandomized observational studies. IC compared with SCnoF was significantly associated with better neurologic outcome (OR, 0.6; 95% CI, 0.49-0.74) and survival (OR, 0.8; 95% CI, 0.66-0.96). IC compared with SCF, and SCF compared with SCnoF did not show significant differences in neurologic outcome and survival. The rankogram showed that IC had the highest probability to be the most beneficial cooling method, followed by SCF and SCnoF.

CONCLUSIONS

Our results suggest that in patients resuscitated from CA and treated with TTM at 32-34°C, IC has the highest probability of being the most beneficial cooling method for survival and neurologic outcome.

Prognostic value of targeted temperature management on outcomes of hanging-induced out-of-hospital cardiac arrest: A nationwide observational study

ABSTRACT

This study aimed to evaluate the prognostic significance of targeted temperature management (TTM) on hanging-induced out-of-hospital cardiac arrest (OHCA) patients using nationwide data of South Korea.Adult hanging-induced OHCA patients from 2008 to 2018 were included in this nationwide observational study. Patients who assigned into 2 groups based on whether they did (TTM group) or did not (non-TTM group) receive TTM. Outcome measures included survival to hospital discharge and a good neurological outcome at hospital discharge.Among the 293,852 OHCA patients, 3545 patients (non-TTM, n = 2762; TTM, n = 783) were investigated. After propensity score matching for all patients, 783 matched pairs were available for analysis. We observed no significant inter-group differences in the survival to hospital discharge (non-TTM, n = 27 [3.4%] vs TTM, n = 23 [2.9%], P = .666) or good neurological outcomes (non-TTM, n = 23 [2.9%] vs TTM, n = 14 [1.8%], P = .183). In the multivariate analysis, prehospital return of spontaneous circulation (odds ratio [OR], 22.849; 95% confidence interval [CI], 11.479-45.481, P < .001) was associated with an increase in survival to hospital discharge, and age (OR, 0.971; 95% CI, 0.944-0.998, P  = .035), heart disease (OR, 16.875; 95% CI, 3.028-94.036, P  = .001), and prehospital return of spontaneous circulation (OR, 133.251; 95% CI, 30.512-581.930, P < .001) were significant prognostic factors of good neurological outcome. However, TTM showed no significant association with either outcome.There were no significant differences in the survival to hospital discharge and good neurological outcomes between non-TTM and TTM groups of hanging-induced OHCA patients.

[Lethal Heatstroke with Disseminated Intravascular Coagulopathy]

We report on a case of severe heat stroke due to extended exposure to the sun in an enclosed glass cabin of an agricultural vehicle. Patient treatment, lab results and complications are reported and we examine the current literature on heat stroke.Heat stroke is a very rare and highly severe condition mostly suffered by vulnerable individuals or individuals exposed to extreme physical strain. Per definition a heat stroke is characterized by neurological deficit (especially loss of consciousness), and a high body temperature. Most important treatment is to lower the body temperature below 40 °C as quickly as possible. The best method is cold water immersion, but there are several other physical and invasive means that can be used. If performed within 30 minutes after the beginning of the incident this treatment decreases mortality considerably.Heat damage affects every organ and organ system. Most important are neurologic deficits, cardiovascular failure, liver failure and kidney failure. The excessive heat triggers a systemic inflammatory response syndrome (SIRS) which can lead to a disseminated intravascular coagulopathy (DIC). Haemostasis is also directly affected by the elevated temperature.Besides physical cooling, there is no known specific treatment to prevent secondary damage from heat stroke. Additionally, supportive care and ICU monitoring should be applied.

Impact of cooling method on the outcome of initial shockable or non-shockable out of hospital cardiac arrest patients receiving target temperature management: a nationwide multicentre cohort study

Background

Little is known about the effectiveness of surface cooling (SC) and endovascular cooling (EC) on the outcome of out-of-hospital cardiac arrest (OHCA) patients receiving target temperature management (TTM) according to their initial rhythm.

Methods

We retrospectively analysed data from the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest registry, a multicentre, prospective nationwide database in Japan. For our analysis, OHCA patients aged ≥ 18 years who were treated with TTM between June 2014 and December 2017 were included. The primary outcome was 30-day survival with favourable neurological outcome defined as a Glasgow–Pittsburgh cerebral performance category score of 1 or 2. Cooling methods were divided into the following groups: SC (ice packs, fans, air blankets, and surface gel pads) and EC (endovascular catheters and any dialysis technique). We investigated the efficacy of the two categories of cooling methods in two different patient groups divided according to their initially documented rhythm at the scene (shockable or non-shockable) using multivariable logistic regression analysis and propensity score analysis with inverse probability weighting (IPW).

Results

In the final analysis, 1082 patients were included. Of these, 513 (47.4%) had an initial shockable rhythm and 569 (52.6%) had an initial non-shockable rhythm. The proportion of patients with favourable neurological outcomes in SC and EC was 59.9% vs. 58.3% (264/441 vs. 42/72), and 11.8% (58/490) vs. 21.5% (17/79) in the initial shockable patients and the initial non-shockable patients, respectively. In the multivariable logistic regression analysis, differences between the two cooling methods were not observed among the initial shockable patients (adjusted odd ratio [AOR] 1.51, 95% CI 0.76–3.03), while EC was associated with better neurological outcome among the initial non-shockable patients (AOR 2.21, 95% CI 1.19–4.11). This association was constant in propensity score analysis with IPW (OR 1.40, 95% CI 0.83–2.36; OR 1.87, 95% CI 1.01–3.47 among the initial shockable and non-shockable patients, respectively).

Conclusion

We suggested that the use of EC was associated with better neurological outcomes in OHCA patients with initial non-shockable rhythm, but not in those with initial shockable rhythm. A TTM implementation strategy based on initial rhythm may be important.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00953-y.

Review of Hypothermia Protocol and Timing of the Echocardiogram

Targeted temperature management, also known as therapeutic hypothermia (TH), is recommended for out-of-hospital cardiac arrest (OHCA). Both internal or external methods of cooling can be applied. Individuals resuscitated from OHCA frequently develop postarrest myocardial dysfunction resulting in decreased cardiac output and left ventricular systolic function. This dysfunction is usually transient and improves with spontaneous recovery over time. Echocardiogram (ECHO) can be a vital tool for the assessment and management of these patients. This manuscript reviewed methods available for TH after OHCA and reviews role of ECHO in the diagnosis and prognosis in this setting.

Temporal Changes in Targeted Temperature Management for Out-of-Hospital Cardiac Arrest-Examining the Effect of the Targeted Temperature Management Trial: A Retrospective Cohort Study

Targeted temperature management (TTM) is recommended after out-of-hospital cardiac arrest (OHCA). However, interpretation of the evidence and translation into clinical practice, to realize benefits to patient outcomes may be inconsistent. This study aims to compare compliance with the recommended targeted temperatures and the use of intravascular temperature management (IVTM), as well as 90-day survival, before and after publication of the TTM trial. A single-center retrospective cohort study was conducted from 2010 to 2017. All comatose patients admitted to the intensive care unit after OHCA, who survived for ≥24 hours, were included. IVTM use was measured and TTM adherence was defined as the percentage time the core temperature was (1) within the guideline-recommended temperature range (initially 32-34°C, later modified to 32-36°C) for the first 24 hours, and (2) ≤37.5°C between 24 and 72 hours following admission. Multiple logistic regression analyses were performed for the use of IVTM and survival at 90 days. Of the 302 patients identified, 136 (45%) were pre-TTM, and 166 (55%) post-TTM. Baseline characteristics were similar between the groups. IVTM use decreased significantly (77.9% vs. 51.8%, p < 0.001) after the publication of the TTM trial. Adherence to the 32-34°C and 32-36°C targets was higher pre-TTM as compared with the post-TTM cohort (33.3% [0-66.7%] vs. 0% [0-16.7%], p < 0.001 and 83.3% [50.0-100%] vs. 36.7% [16.7-66.7%], p < 0.001, respectively). Time with temperature ≥37.5°C in the first 24 hours was higher post-TTM (p = < 0.001) but not between 24 and 72 hours. Ninety-day survival was 54.4% in the pre-TTM cohort and 44.0% post-TTM, (odds ratio 1.52 [0.96-2.40], p = 0.083). Adherence with recommended TTM decreased significantly following publication of the TTM trial and this was explained by a significant decrease in IVTM use. However, this concerning trend did not result in a statistically significant difference in survival.

Use of a Servo-Controlled Cooling Gel Pad System to Regulate Body Temperature in Critically Ill Children

OBJECTIVES

To assess the efficacy and safety of a servo-controlled cooling pad system for target temperature management in critically ill pediatric patients.

DESIGN

A prospective, single-center, observational study.

SETTING

PICU of a tertiary hospital from September 2018 to September 2019.

PATIENTS

Children from 28 days to 16 years old subjected to servo-controlled body temperature control.

METHODS

The Arctic Sun 5000 system (Bard Medical, Covington, GA) and Arctic Gel Hydrogel pads were used for the purposes of the study. Data collected included demographics, indication of therapy, patient's body temperature, target temperature, time-to-target temperature, duration of therapy, and need to start or increase sedation and/or muscle relaxants.

MEASUREMENTS AND MAIN RESULTS

A total of 16 patients were included, of whom 68.8% were male; mean age was 4.7 years. The most frequent indication was fever associated with hemodynamic instability (62.5%). The target temperature was normothermia (36 or 36.5°C) in 81% of cases. Mean baseline body temperature was 37.6°C (± 1.2°C), and 50% of patients had fever (> 38°C). The mean speed of cooling was 1.2°C/hr (± 1°C/hr). Mean time to target temperature was 118 minutes (± 98.8 min). Mean duration of therapy was 68.7 hours (± 58.3 hr). Two patients had fever related to device disconnection during the treatment. At the start of the therapy, 15 patients were receiving sedative and analgesic drugs, and four received muscle relaxants. A patient required increased sedation, whereas another patient needed to start muscle relaxants. One of the patients developed a skin lesion in the axilla, no other adverse events were registered.

CONCLUSIONS

Despite the small sample size, the results of the study showed that target temperature management by the servo-controlled gel pad system in critically ill pediatric patients was effective in achieving satisfactory temperature control and it was well-tolerated.

Association of Initial Illness Severity and Outcomes After Cardiac Arrest With Targeted Temperature Management at 36 °C or 33 °C

IMPORTANCE

It is uncertain what the optimal target temperature is for targeted temperature management (TTM) in patients who are comatose following cardiac arrest.

OBJECTIVE

To examine whether illness severity is associated with changes in the association between target temperature and patient outcome.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study compared outcomes for 1319 patients who were comatose after cardiac arrest at a single center in Pittsburgh, Pennsylvania, from January 2010 to December 2018. Initial illness severity was based on coma and organ failure scores, presence of severe cerebral edema, and presence of highly malignant electroencephalogram (EEG) after resuscitation.

EXPOSURE

TTM at 36 °C or 33 °C.

MAIN OUTCOMES AND MEASURES

Primary outcome was survival to hospital discharge, and secondary outcomes were modified Rankin Scale and cerebral performance category.

RESULTS

Among 1319 patients, 728 (55.2%) had TTM at 33 °C (451 [62.0%] men; median [interquartile range] age, 61 [50-72] years) and 591 (44.8%) had TTM at 36 °C (353 [59.7%] men; median [interquartile range] age, 59 [48-69] years). Overall, 184 of 187 patients (98.4%) with severe cerebral edema died and 234 of 243 patients (96.3%) with highly malignant EEG died regardless of TTM strategy. Comparing TTM at 33 °C with TTM at 36 °C in 911 patients (69.1%) with neither severe cerebral edema nor highly malignant EEG, survival was lower in patients with mild to moderate coma and no shock (risk difference, -13.8%; 95% CI, -24.4% to -3.2%) but higher in patients with mild to moderate coma and cardiopulmonary failure (risk difference, 21.8%; 95% CI, 5.4% to 38.2%) or with severe coma (risk difference, 9.7%; 95% CI, 4.0% to 15.3%). Interactions were similar for functional outcomes. Most deaths (633 of 968 [65.4%]) resulted after withdrawal of life-sustaining therapies.

CONCLUSIONS AND RELEVANCE

In this study, TTM at 33 °C was associated with better survival than TTM at 36 °C among patients with the most severe post-cardiac arrest illness but without severe cerebral edema or malignant EEG. However, TTM at 36 °C was associated with better survival among patients with mild- to moderate-severity illness.

Feasibility and Performance of a Gel-Adhesive Pad System for Pediatric Targeted Temperature Management: An Exploratory Analysis of 19 Pediatric Critically Ill Patients

Targeted temperature management (TTM) is an important treatment modality in pediatric neurocritical care. There are different types of devices available to deliver this therapy, but limited pediatric data exist. This quality improvement study evaluates the use of a surface cooling device that uses gel-adhesive pads for TTM in critically ill pediatric patients. An institutional TTM protocol to use the gel-adhesive pad system was developed with three different temperature goals: normothermia (goal temperature 37°C), mild hypothermia (goal temperature 35°C with rewarming duration of 12 hours to normothermia), and moderate hypothermia (goal temperature 33°C with rewarming duration of 24 hours to normothermia). Protocol and device implementation required several different educational sessions for all members of the critical care team. An exploratory analysis was performed for 19 patients with complete clinical and device temperature data. The most common protocol used was normothermia (73.6%). By protocol, time to goal temperature was 58 minutes (22.0-112.8) for normothermia, 46.5 minutes (44.3-48.8) for mild hypothermia, and 93 minutes (46.5-406.5) for moderate hypothermia. Patients remained within ±0.5°C temperature goal 99% (96.0-99.3) of the time in the normothermia protocol, 99.5% (99-100) in mild hypothermia, and 93% (80-100) for the moderate hypothermia protocol. Shivering was the most common adverse event (35%). Our results show that use of the gel-adhesive pad system for pediatric TTM is feasible, efficacious with regard to achieving both a short time to target temperature and maintaining temperature goal, and, in this limited sample, was free from major adverse events. We also defined several technical aspects of device use in pediatric patients that should be considered in future trial design and/or clinical use. Further studies are needed to determine if this device is superior to other cooling devices for temperature management in the pediatric population.

State-of-the-art considerations in post-arrest care

Cardiac arrest has a high rate of morbidity and mortality. Several advances in post-cardiac arrest management can improve outcome, but are time-dependent, placing the emergency physician in a critical role to both recognize the need for and initiate therapy. We present a novel perspective of both the workup and therapeutic interventions geared toward the emergency physician during the first few hours of care. We describe how the immediate care of a post-cardiac arrest patient is resource intensive and requires simultaneous evaluation for the underlying cause and intensive management to prevent further end organ damage, particularly of the central nervous system. The goal of the initial focused assessment is to rapidly determine if any reversible causes of cardiac arrest are present and to intervene when possible. Interventions performed in this acute period are aimed at preventing additional brain injury through optimizing hemodynamics, providing ventilatory support, and by using therapeutic hypothermia when indicated. After the initial phase of care, disposition is guided by available resources and the clinician's judgment. Transfer to a specialized cardiac arrest center is prudent in centers that do not have significant support or experience in the care of these patients.

Effects of endovascular and surface cooling on resuscitation in patients with cardiac arrest and a comparison of effectiveness, stability, and safety: a systematic review and meta-analysis

Objectives

This study conducted a meta-analysis to assess the effectiveness, stability, and safety of mild therapeutic hypothermia (TH) induced by endovascular cooling (EC) and surface cooling (SC) and its effect on ICU, survival rate, and neurological function integrity in adult CA patients.

Methods

We developed inclusion criteria, intervention protocols, results, and data collection. The results included outcomes during target temperature management as well as ICU stay, survival rate, and neurological functional integrity. The characteristics of the included population and each study were analyzed.

Results

Four thousand nine hundred thirteen participants met the inclusion criteria. Those receiving EC had a better cooling efficiency (cooling rates MD = 0.31[0.13, 0.50], p < 0.01; induced cooling times MD = − 90.45[− 167.57, − 13.33], p = 0.02; patients achieving the target temperature RR = 1.60[1.19, 2.15], p < 0.01) and thermal stability during the maintenance phase (maintenance time MD = 2.35[1.22, 3.48], p < 0.01; temperature fluctuation MD = − 0.68[− 1.03, − 0.33], p < 0.01; overcooling RR = 0.33[0.23, 0.49], p < 0.01). There were no differences in ICU survival rate (RR = 1.22[0.98, 1.52], p = 0.07, I² = 0%) and hospital survival rate (RR = 1.02 [0.96, 1.09], p = 0.46, I² = 0%), but EC reduced the length of stay in ICU (MD = − 1.83[− 3.45, − 0.21], p = 0.03, I² = 49%) and improved outcome of favorable neurological function at discharge (RR = 1.15[1.04, 1.28], p < 0.01, I² = 0%). EC may delay the hypothermia initiation time, and there was no significant difference between the two cooling methods in the time from the start of patients’ cardiac arrest to achieve the target temperature (MD = − 46.64[− 175.86, 82.58]). EC was superior to non-ArcticSun in terms of cooling efficiency. Although there was no statistical difference in ICU survival rate, ICU length of stay, and hospitalization survival rate, in comparison to non-ArcticSun, EC improved rates of neurologically intact survival (RR = 1.16 [1.01, 1.35], p = 0.04, I² = 0%).

Conclusions

Among adult patients receiving cardiopulmonary resuscitation, although there is no significant difference between the two cooling methods in the time from the start of cardiac arrest to achieve the target temperature, the faster cooling rate and more stable cooling process in EC shorten patients’ ICU hospitalization time and help more patients obtain good neurological prognosis compared with patients receiving SC. Meanwhile, although EC has no significant difference in patient outcomes compared with ArcticSun, EC has improved rates of neurologically intact survival.

Systematic review and meta-analysis of intravascular temperature management vs. surface cooling in comatose patients resuscitated from cardiac arrest

OBJECTIVE

To systematically review the effectiveness and safety of intravascular temperature management (IVTM) vs. surface cooling methods (SCM) for induced hypothermia (IH).

METHODS

Systematic review and meta-analysis. English-language PubMed, Embase and the Cochrane Database of Systematic Reviews were searched on May 27, 2019. The quality of included observational studies was graded using the Newcastle-Ottawa Quality Assessment tool. The quality of included randomized trials was evaluated using the Cochrane Collaboration's risk of bias tool. Random effects modeling was used to calculate risk differences for each outcome. Statistical heterogeneity and publication bias were assessed using standard methods.

ELIGIBILITY

Observational or randomized studies comparing survival and/or neurologic outcomes in adults aged 18 years or greater resuscitated from out-of-hospital cardiac arrest receiving IH via IVTM vs. SCM were eligible for inclusion.

RESULTS

In total, 12 studies met inclusion criteria. These enrolled 1573 patients who received IVTM; and 4008 who received SCM. Survival was 55.0% in the IVTM group and 51.2% in the SCM group [pooled risk difference 2% (95% CI -1%, 5%)]. Good neurological outcome was achieved in 40.9% in the IVTM and 29.5% in the surface group [pooled risk difference 5% (95% CI 2%, 8%)]. There was a 6% (95% CI 11%, 2%) lower risk of arrhythmia with use of IVTM and 15% (95% CI 22%, 7%) decreased risk of overcooling with use of IVTM vs. SCM. There was no significant difference in other evaluated adverse events between groups.

CONCLUSIONS

IVTM was associated with improved neurological outcomes vs. SCM among survivors resuscitated following cardiac arrest. These results may have implications for care of patients in the emergency department and intensive care settings after resuscitation from cardiac arrest.

How to manage fever in brain-injured patients

Fever represents a frequent and dangerous secondary insult for the injured brain and is often associated with worsened neurological outcomes. The identification of fever in the Neuro-Intensive Care Unit requires careful monitoring and rapid and effective treatment. The main objective of this article was to provide practical information regarding temperature monitoring, triggers for intervention and fever management in brain injured patients.

Effect of different methods of cooling for targeted temperature management on outcome after cardiac arrest: a systematic review and meta-analysis

Background

Although targeted temperature management (TTM) is recommended in comatose survivors after cardiac arrest (CA), the optimal method to deliver TTM remains unknown. We performed a meta-analysis to evaluate the effects of different TTM methods on survival and neurological outcome after adult CA.

Methods

We searched on the MEDLINE/PubMed database until 22 February 2019 for comparative studies that evaluated at least two different TTM methods in CA patients. Data were extracted independently by two authors. We used the Newcastle-Ottawa Scale and a modified Cochrane ROB tools for assessing the risk of bias of each study. The primary outcome was the occurrence of unfavorable neurological outcome (UO); secondary outcomes included overall mortality.

Results

Our search identified 6886 studies; 22 studies (n = 8027 patients) were included in the final analysis. When compared to surface cooling, core methods showed a lower probability of UO (OR 0.85 [95% CIs 0.75–0.96]; p = 0.008) but not mortality (OR 0.88 [95% CIs 0.62–1.25]; p = 0.21). No significant heterogeneity was observed among studies. However, these effects were observed in the analyses of non-RCTs. A significant lower probability of both UO and mortality were observed when invasive TTM methods were compared to non-invasive TTM methods and when temperature feedback devices (TFD) were compared to non-TFD methods. These results were significant particularly in non-RCTs.

Conclusions

Although existing literature is mostly based on retrospective or prospective studies, specific TTM methods (i.e., core, invasive, and with TFD) were associated with a lower probability of poor neurological outcome when compared to other methods in adult CA survivors (CRD42019111021).

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2567-6) contains supplementary material, which is available to authorized users.

A new paradigm for lung-conservative total liquid ventilation

Background

Total liquid ventilation (TLV) of the lungs could provide radically new benefits in critically ill patients requiring lung lavage or ultra-fast cooling after cardiac arrest. It consists in an initial filling of the lungs with perfluorocarbons and subsequent tidal ventilation using a dedicated liquid ventilator. Here, we propose a new paradigm for a lung-conservative TLV using pulmonary volumes of perfluorocarbons below functional residual capacity (FRC).

Methods and findings

Using a dedicated technology, we showed that perfluorocarbon end-expiratory volumes could be maintained below expected FRC and lead to better respiratory recovery, preserved lung structure and accelerated evaporation of liquid residues as compared to complete lung filling in piglets. Such TLV below FRC prevented volutrauma through preservation of alveolar recruitment reserve. When used with temperature-controlled perfluorocarbons, this lung-conservative approach provided neuroprotective ultra-fast cooling in a model of hypoxic-ischemic encephalopathy. The scale-up and automating of the technology confirmed that incomplete initial lung filling during TLV was beneficial in human adult-sized pigs, despite larger size and maturity of the lungs. Our results were confirmed in aged non-human primates, confirming the safety of this lung-conservative approach.

Interpretation

This study demonstrated that TLV with an accurate control of perfluorocarbon volume below FRC could provide the full potential of TLV in an innovative and safe manner. This constitutes a new paradigm through the tidal liquid ventilation of incompletely filled lungs, which strongly differs from the previously known TLV approach, opening promising perspectives for a safer clinical translation.

Fund

ANR (COOLIVENT), FRM (DBS20140930781), SATT IdfInnov (project 273).

[Postcardiac arrest treatment guide]

BACKGROUND

Treatment after cardiac arrest has become more complex and interdisciplinary over the last few years. Thus, the clinically active intensive and emergency care physician not only has to carry out the immediate care and acute diagnostics, but also has to prognosticate the neurological outcome.

AIM

The different, most important steps are presented by leading experts in the area, taking into account the interdisciplinarity and the currently valid guidelines.

MATERIALS AND METHODS

Attention was paid to a concise, practice-oriented presentation.

RESULTS AND DISCUSSION

The practical guide contains all important steps from the acute care to the neurological prognosis generation that are relevant for the clinically active intensive care physician.

Esophageal Heat Exchanger Versus Water-Circulating Cooling Blanket for Targeted Temperature Management

To date, the optimal cooling device for targeted temperature management (TTM) remains unclear. Water-circulating cooling blankets are broadly available and quickly applied but reveal inaccuracy during maintenance and rewarming period. Recently, esophageal heat exchangers (EHEs) have been shown to be easily inserted, revealed effective cooling rates (0.26-1.12°C/h), acceptable deviations from target core temperature (<0.5°C), and rewarming rates between 0.2 and 0.4°C/h. The aim of this study was to compare cooling rates, accuracy during maintenance, and rewarming period as well as side effects of EHEs with water-circulating cooling blankets in a porcine TTM model. Mean core temperature of domestic pigs (n = 16) weighing 83.2 ± 3.6 kg was decreased to a target core temperature of 33°C by either using EHEs or water-circulating cooling blankets. After 8 hours of maintenance, rewarming was started at a goal rate of 0.25°C/h. Mean cooling rates were 1.3 ± 0.1°C/h (EHE) and 3.2 ± 0.5°C/h (blanket, p < 0.0002). Mean difference to target core temperature during maintenance ranged between ±1°C. Mean rewarming rates were 0.21 ± 0.01°C/h (EHE) and 0.22 ± 0.02°C/h (blanket, n.s.). There were no differences with regard to side effects such as brady- or tachycardia, hypo- or hyperkalemia, hypo- or hyperglycemia, hypotension, shivering, or esophageal tissue damage. Target temperature can be achieved faster by water-circulating cooling blankets. EHEs and water-circulating cooling blankets were demonstrated to be reliable and safe cooling devices in a prolonged porcine TTM model with more variability in EHE group.

Intravascular versus surface cooling for targeted temperature management after out-of-hospital cardiac arrest: an analysis of the TTH48 trial

Background

The aim of this study was to explore the performance and outcomes for intravascular (IC) versus surface cooling devices (SFC) for targeted temperature management (TTM) after out-of-hospital cardiac arrest.

Methods

A retrospective analysis of data from the Time-differentiated Therapeutic Hypothermia (TTH48) trial (NCT01689077), which compared whether TTM at 33 °C for 48 h results in better neurologic outcomes compared with standard 24-h duration. Devices were assessed for the speed of cooling and rewarming rates. Precision was assessed by measuring temperature variability (TV), i.e., the standard deviation (SD) of all temperature measurements in the cooling phase. Main outcomes were overall mortality and poor neurological outcome, including death, severe disability, or vegetative status.

Results

A total of 352 patients had available data and were included in the analysis; of those, 218 (62%) were managed with IC. A total of 114/218 (53%) patients with IC and 61/134 (43%) with SFC were cooled for 48 h (p = 0.22). Time to target temperature (≤ 34 °C) was significantly shorter for patients treated with endovascular devices (2.2 [1.1–4.0] vs. 4.2 [2.7–6.0] h, p < 0.001), but temperature was also lower on admission (35.0 [34.2–35.6] vs. 35.3 [34.5–35.8]°C; p = 0.02) and cooling rate was similar (0.4 [0.2–0.8] vs. 0.4 [0.2–0.6]°C/h; p = 0.14) when compared to SFC. Temperature variability was significantly lower in the endovascular device group when compared with SFC methods (0.6 [0.4–0.9] vs. 0.7 [0.5–1.0]°C; p = 0.007), as was rewarming rate (0.31 [0.22–0.44] vs. 0.37 [0.29–0.49]°C/hour; p = 0.02). There was no statistically significant difference in mortality (endovascular 65/218, 29% vs. others 43/134, 32%; p = 0.72) or poor neurological outcome (endovascular 69/218, 32% vs. others 51/134, 38%; p = 0.24) between type of devices.

Conclusions

Endovascular cooling devices were more precise than SFC methods in patients cooled at 33 °C after out-of-hospital cardiac arrest. Main outcomes were similar with regard to the cooling methods.