Surface cooling after cardiac arrest: effectiveness, skin safety, and adverse events in routine clinical practice

Minimizing Shivering During Targeted Normothermia: Comparison Between Novel Transnasal and Surface Temperature-Modulating Devices

BACKGROUND

Shivering is a common adverse effect of achieving and maintaining normothermia in neurocritical care patients. We compared the burden of shivering and shivering-related interventions between a novel transnasal temperature-modulating device (tnTMD) and surface cooling temperature-modulating devices (sTMDs) during the first 24 h of targeted normothermia in mechanically ventilated febrile neurocritical care patients.

METHODS

This is a case-control study controlling for factors that impact shiver burden: age, sex, body surface area. All patients underwent transnasal cooling (CoolStat, KeyTech, Inc.) as part of an ongoing multicenter clinical trial (NCT03360656). Patients undergoing treatment with sTMDs were selected from consecutively treated patients during the same time period. Data collected included the following: core body temperature (every 2 h), bedside shivering assessment scale (BSAS) score (every 2 h), and administration of antishivering medication for a BSAS score > 1. Time to normothermia (≤ 37.5 °C), as well as temperature burden > 37.5 °C (°C × h), were compared between groups using Student's t-test for mean differences. The proportion of patients requiring interventions, as well as the number of interventions per patient, was compared using the χ2 test. Significance was determined based on a p value < 0.05.

RESULTS

There were 10 tnTMD patients and 30 sTMD patients included in the analysis (mean age: 62 ± 4, 30% women, body surface area = 1.97 ± 0.25). There were no differences between groups in temperature at cooling initiation (tnTMD: 38.5 ± 0.2 °C vs. sTMD: 38.7 ± 0.5 °C, p = 0.3), time to ≤ 37.5 °C (tnTMD: 1.8 ± 1.5 h vs. sTMD: 2.9 ± 1.4 h, p = 0.1), or temperature burden > 37.5 (tnTMD: - 0.4 ± 1.13 °C × h vs. sTMD median [IQR]: - 0.57 ± 0.58 °C × h, p = 0.67). The number of tnTMD patients who received pharmacologic shivering interventions was lower than the number of controls (20 vs. 67%, p = 0.01). tnTMD patients also had fewer shivering interventions per patient (0 [range: 0-3] vs. 4 [range: 0-23], p < 0.001).

CONCLUSIONS

A transnasal cooling approach achieved similar time to normothermia and temperature burden with less shivering than surface cooling. This approach may be a feasible option to consider for mechanically ventilated febrile neurocritical care patients.

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.

Temperature Control After Cardiac Arrest: A Narrative Review

Cardiac arrest (CA) is a critical public health issue affecting more than half a million Americans annually. The main determinant of outcome post-CA is hypoxic-ischemic brain injury (HIBI), and temperature control is currently the only evidence-based, guideline-recommended intervention targeting secondary brain injury. Temperature control is a key component of a post-CA care bundle; however, conflicting evidence challenges its wide implementation across the vastly heterogeneous population of CA survivors. Here, we critically appraise the available literature on temperature control in HIBI, detail how the evidence has been integrated into clinical practice, and highlight the complications associated with its use and the timing of neuroprognostication after CA. Future clinical trials evaluating different temperature targets, rates of rewarming, duration of cooling, and identifying which patient phenotype benefits from different temperature control methods are needed to address these prevailing knowledge gaps.

Nursing Management of Temperature in a Patient with Stroke

Fever is common in patients with stroke and is associated with worse outcomes. Studies in brain injury informed interventions commonly termed therapeutic temperature management (TTM) to improve the monitoring and management of fever. While the role and benefit of TTM in stroke patients has not been well studied, the nurse and healthcare team must extrapolate existing data to determine how to best monitor and apply TTM after stroke. Nurses should be knowledgeable about interventions to monitor and manage complications of TTM (eg, shivering), the studies underway to quantify the impact of fever treatment and emerging technology expected to improve TTM.

Safety and Feasibility of a Novel Transnasal Cooling Device to Induce Normothermia in Febrile Cerebrovascular Patients

BACKGROUND

Inducing normothermia with surface cooling temperature modulating devices (TMDs) is cumbersome and often associated with significant shivering. We tested the safety and feasibility of a novel transnasal evaporative cooling device to induce and maintain normothermia in febrile patients following ischemic and hemorrhagic stroke.

METHODS

A single-center study utilizing the CoolStat® transnasal cooling device was used to achieve core temperature reduction in mechanically ventilated stroke patients with fever (T ≥ 38.3 C) refractory to acetaminophen by inducing an evaporative cooling energy exchange in the nasal turbinates thru a high flow of dehumidified air into the nasal cavity and out through the mouth. Continuous temperature measurements were obtained from tympanic and core (esophageal or bladder) temperature monitors. Safety assessments included continuous monitoring for hypertension, tachycardia, and raised intracranial pressure (when monitored). Otolaryngology (ENT) evaluations were monitored for any device-related nasal mucosal injury with a pre- and post-visual examination. Shivering was assessed every 30 min using the Bedside Shivering Assessment Scale (BSAS). Duration of device use was limited to 8 h, at which time patients were transitioned to routine care for temperature management.

RESULTS

Ten subjects (median age: 54 years, BMI: 32.5 kg/m², 60% men) were enrolled with normothermia achieved in 90% of subjects. One subject did not achieve normothermia and was later refractory to other TMDs. Median baseline temperature was 38.5 ± 0.1 C, with a reduction noted by 4 h (38.5 ± 0.1 vs 37.3 ± 0.8, P < 0.001) and sustained at 8 h (38.5 ± 0.1 vs 37.1 ± 0.7, P = 0.001). Time to normothermia was 2.6 ± 1.9 h. The median BSAS was 0 (range 0-1) with only 4 episodes necessitating meperidine across 76 h of study monitoring. No treatment was discontinued due to safety concerns. ENT evaluations noted no device-related adverse findings.

CONCLUSIONS

Inducing normothermia with a novel transnasal TMD appears to be safe, feasible and not associated with significant shivering. A multicenter trial testing the ability of the CoolStat to maintain normothermia for 24 h is currently underway.

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.

A comparison of intravascular and surface cooling devices for targeted temperature management after out-of-hospital cardiac arrest: A nationwide observational study

This study aimed to compare prognostic difference between intravascular cooling devices (ICDs) and surface cooling devices (SCDs) in targeted temperature management (TTM) recipients.Adult TTM recipients using ICD or SCD during 2012 to 2016 were included in this nationwide observational study. The outcome was survival to hospital discharge and good neurological outcome at hospital discharge.Among 142,905 out-of-hospital cardiac arrest patients, 1159 patients (SCD, n = 998; ICD, n = 161) were investigated. After propensity score matching for all patients, 161 matched pairs of patients were available for analysis (SCD, n = 161; ICD, n = 161). We observed no significant differences in the survival to hospital discharge (SCD, n = 144 [89.4%] vs ICD, n = 150 [93.2%], P = .32) and the good neurological outcomes (SCD, n = 86 [53.4%] vs ICD, n = 91 [56.5%], P = .65). TTM recipients were categorized by age groups (elderly [age >65 years] vs nonelderly [age ≤65 years]) to compare prognostic difference between ICD and SCD according to the age groups. In the nonelderly group, the use of ICD or SCD was not a significant factor for survival to hospital discharge or good neurologic outcome. Whereas, the use of ICD was significantly associated with good neurological outcome (odds ratio, 3.97; 95% confidence interval, 1.19 - 13.23, P = .02) compared with SCD in the elderly group.There were no significant differences in the survival to hospital discharge and the good neurological outcomes between SCD and ICD recipients. However, the use of ICD might be more beneficial than SCD in elderly patients.

Retrospective Analysis of Esophageal Heat Transfer for Active Temperature Management in Post-cardiac Arrest, Refractory Fever, and Burn Patients

Core temperature management is an important aspect of critical care; preventing unintentional hypothermia, reducing fever, and inducing therapeutic hypothermia when appropriate are each tied to positive health outcomes. The purpose of this study is to evaluate the performance of a new temperature management device that uses the esophageal environment to conduct heat transfer. De-identified patient data were aggregated from three clinical sites where an esophageal heat transfer device (EHTD) was used to provide temperature management. The device was evaluated against temperature management guidelines and best practice recommendations, including performance during induction, maintenance, and cessation of therapy. Across all active cooling protocols, the average time-to-target was 2.37 h and the average maintenance phase was 22.4 h. Patients spent 94.9% of the maintenance phase within ±1.0°C and 67.2% within ±0.5°C (574 and 407 measurements, respectively, out of 605 total). For warming protocols, all of the patient temperature readings remained above 36°C throughout the surgical procedure (average 4.66 h). The esophageal heat transfer device met performance expectations across a range of temperature management applications in intensive care and burn units. Patients met and maintained temperature goals without any reported adverse events.

Effect of high flow transnasal dry air on core body temperature in intubated human subjects

PURPOSE

Early initiation of hypothermia is recommended in the setting of cardiac arrest. Current hypothermia methods are invasive and expensive and not applicable in ambulatory settings. We investigated the evaporative cooling effect of high flow transnasal dry air on core esophageal temperature in human volunteers.

METHODS & RESULTS

A total of 32 subjects (mean age 53.2 ± 9.3 yrs., mean weight 90 ± 17 kg) presenting for elective electrophysiological procedures were enrolled for the study. Half of the subjects were men. Following general anesthesia induction, high flow (30 LPM) medical grade ambient dry air with a relative humidity ∼20% was administered through a nasal mask for 60 min. Core temperature was monitored at the distal esophagus. Half of the subjects (16/32) were subject to high flow air and the remainder served as controls. Over a 1-h period, mean esophageal temperature decreased from 36.1 ± 0.3 °C to 35.5 ± 0.1 °C in the test subjects (p < 0.05). No significant change in temperature was observed in the control subjects (36.3 ± 0.3 °C to 36.2 ± 0.2 °C, p = NS). No adverse events occurred.

CONCLUSION

Transnasal high flow dry air through the nasopharynx reduces core body temperature. This mechanism can be harnessed to induce hypothermia in patients where clinically indicated without any deleteriouseffects in a short time exposure.

Cold Blooded: Evaluating Brain Temperature by MRI During Surface Cooling of Human Subjects

BACKGROUND

Targeted temperature management (TTM) confers neurological and survival benefits for post-cardiac arrest patients with return of spontaneous circulation (ROSC) who remain comatose. Specialized equipment for induction of hypothermia is not available in the prehospital setting, and there are no reliable methods for emergency medical services personnel to initiate TTM. We hypothesized that the application of surface cooling elements to the neck will decrease brain temperature and act as initiators of TTM.

METHODS

Magnetic resonance (MR) spectroscopy was used to evaluate the effect of a carotid surface cooling element on brain temperature in healthy adults.

RESULTS

Six individuals completed this study. We measured a temperature drop of 0.69 ± 0.38 °C (95% CI) in the cortex of the brain following the application of the cooling element. Application of a room temperature element also caused a measurable decrease in brain temperature of 0.66 ± 0.41 °C (95% CI) which may be attributable to baroreceptor activation.

CONCLUSION

The application of surface cooling elements to the neck decreased brain temperature and may serve as a method to initiate TTM in the prehospital setting.

Post-resuscitation care

Following return of spontaneous circulation (ROSC) after cardiac arrest, the challenge is to institute measures that ensure a higher likelihood of neurologically intact survival. Regardless of the cause of collapse, multiple organ systems may be affected secondary to post-cardiac arrest syndrome. Interventions required for post-ROSC care are bundled into a care regimen: prompt identification and treatment of the cause of cardiac arrest; and treatment of electrolyte abnormalities. It is also essential to establish definitive airway management to maintain normocapnic ventilation, prevent hyperoxia, and optimise haemodynamic management via judicious intravenous fluids and vasoactive drugs. Targeted temperature management after ROSC confers neuroprotection and leads to improved neurological outcomes. Glycaemic control of blood glucose levels at 6-10 mmol/L, adequate seizure management and measures to optimise neurological functions should be integrated into the care bundle. The interventions outlined can potentially lead to more patients being discharged from hospital alive with good neurological function.

Use of therapeutic hypothermia among patients with coagulation disorders - A Nationwide analysis

OBJECTIVES

The study aimed to assess the impact of therapeutic hypothermia (TH) on bleeding and in-hospital mortality among patients with coagulation disorders (CD).

BACKGROUND

TH affects coagulation factors and platelets putting patients at risk for bleeding and worse outcomes. Effect of TH among patients with CD remains understudied.

METHODS

Between 2009 and 2014, a total of 6469 cases of TH were identified using the National Inpatient Sample out of which 1036 (16.02%) had a CD. The incidence of bleeding events, blood product transfusion and in-hospital mortality was compared between patients with and without CD using one to one propensity score matching.

RESULTS

Proportion of patients with CD increased during study duration from 13.0% to 17.4% from 2009 to 2014. Propensity matching was performed to adjust for baseline differences with 799 patients in both groups depending on presence or absence of CD. Patients with CD had a higher rate of bleeding events (13% vs. 8.5%; adjusted odds ratio 1.60; 95% confidence interval 1.16-2.23; P = 0.004), and blood product transfusion (25.0% vs. 14.1%; aOR 2.03; 95% CI 1.56-2.63; p < 0.001) compared to those without CD. There was no difference in rate of intracranial bleeding or hemorrhagic strokes between those with and without CD (3.3% vs. 3.2%; p = 0.88). There was no difference in mortality between patients with CD and those without (74.5% vs. 74.8%, aOR 0.98, 95% CI 0.78-1.23; P = 0.86).

CONCLUSIONS

Use of TH with CD resulted in more bleeding events and blood product transfusion but there was no difference in hospital mortality.

Thermoregulation in brain injury

Different mechanisms explain thermoregulatory dysfunction following ischemic stroke, hemorrhagic stroke, and traumatic brain injury. Temperature instability following brain injury likely involves hypothalamic injury, pathologic changes in cerebral blood flow, metabolic derangement, and a neurogenic inflammatory response. Although targeted temperature management (TTM) exerts pleiotropic effects, the heterogeneity of brain injury has hindered identification of patient subsets most likely to benefit from TTM. Early optimism about TTM's role in brain injury has been tempered by the failure of successive clinical trials to show improved patient outcomes. However, given the deleterious effects of fever, aggressive fever management is still warranted in the critically ill neurologic patient.

The esophageal cooling device: A new temperature control tool in the intensivist's arsenal

BACKGROUND

Therapeutic hypothermia has been demonstrated to improve neurological outcome in comatose survivors of cardiac arrest. Current temperature control modalities however, have several limitations. Exploring innovative methods of temperature management has become a necessity.

METHODS

We describe the first use of a novel esophageal cooling device as a sole modality for hypothermia induction, maintenance and rewarming in a series of four postcardiac arrest patients. The device was inserted in a manner similar to standard orogastric tubes and connected to an external heat exchange unit.

RESULTS

A mean cooling rate of 0.42 °C/hr (SD ± 0.26) was observed. An average of 4 hr 24 min (SD ± 2 hr 6 min) was required to reach target temperature, and this was maintained 90.25% (SD ± 16.20%) of the hypothermia protocol duration. No adverse events related to device use were encountered. Questionnaires administered to ICU nursing staff regarding ease-of-use of the device and its performance were rated as favorable.

CONCLUSIONS

When used as a sole modality, objective performance parameters of the esophageal-cooling device were found to be comparable to standard temperature control methods. More research is required to further quantify efficacy, safety, assess utility in other patient populations, and examine patient outcomes with device use in comparison to standard temperature control modalities.

Temperature control in critically ill patients with a novel esophageal cooling device: a case series

BACKGROUND

Mild hypothermia and fever control have been shown to improve neurological outcomes post cardiac arrest. Common methods to induce hypothermia include body surface cooling and intravascular cooling; however, a new approach using an esophageal cooling catheter has recently become available.

METHODS

We report the first three cases of temperature control using an esophageal cooling device (ECD). The ECD was placed in a similar fashion to orogastric tubes. Temperature reduction was achieved by connecting the ECD to a commercially available external heat exchange unit (Blanketrol Hyperthermia - Hypothermia System).

RESULTS

The first patient, a 54 year-old woman (86 kg) was admitted after resuscitation from an out-of-hospital non-shockable cardiac arrest. Shortly after admission, she mounted a fever peaking at 38.3 °C despite administration of cold intravenous saline and application of cooling blankets. ECD utilization resulted in a temperature reduction to 35.7 °C over a period of 4 h. She subsequently recovered and was discharged home at day 23. The second patient, a 59 year-old man (73 kg), was admitted after successful resuscitation from a protracted out-of hospital cardiac arrest. His initial temperature was 35 °C, but slowly increased to 35.8 °C despite applying a cooling blanket and ice packs. The ECD was inserted and a temperature reduction to 34.8 °C was achieved within 3 h. The patient expired on day 3. The third patient, a 47 year-old man (95 kg) presented with a refractory fever secondary to necrotizing pneumonia in the postoperative period after coronary artery bypass grafting. His fever persisted despite empiric antibiotics, antipyretics, cooling blankets, and ice packs. ECD insertion resulted in a decrease in temperature from 39.5 to 36.5 °C in less than 5 h. He eventually made a favorable recovery and was discharged home after 59 days. In all 3 patients, device placement occurred in under 3 min and ease-of-use was reported as excellent by nursing staff and physicians.

CONCLUSIONS

The esophageal cooling device was found to be an effective temperature control modality in this small case series of critically ill patients. Preliminary data presented in this report needs to be confirmed in large randomized controlled trials comparing its efficacy and safety to standard temperature control modalities.

Therapeutic hypothermia post-cardiac arrest: a clinical nurse specialist initiative in Pakistan

PURPOSE

The purpose of this project was to assess the feasibility of an evidence-based therapeutic hypothermia protocol in adult post-cardiac arrest (CA) patients in a university hospital in Pakistan.

BACKGROUND

Cardiac arrest has a deleterious effect on neurological function, and survival is associated with significant morbidity. The International Liaison Committee of Cardiopulmonary Resuscitation and the American Heart Association recommend the use of mild hypothermia in post-CA victims to mitigate brain injury caused by anoxia. In Pakistan, the survival rate in CA victims is poor. At present, there are no hospitals in the country that use the evidence-based hypothermia intervention in adult post-CA victims.

DESCRIPTION

This pilot project of therapeutic hypothermia in adult post-CA patients was implemented in a university hospital in Pakistan by a clinical nurse specialist in collaboration with the cardiopulmonary resuscitation committee and the nursing leadership of the hospital. Various clinical nurse specialist competencies and roles were used to address the 3 spheres of influence: patient, nurses, and system, while executing an evidence-based hypothermia protocol. Process and outcome indicators were monitored to evaluate the effectiveness and feasibility of hypothermia intervention in this setting.

OUTCOME

The hypothermia protocol was successfully implemented in 3 adult post-CA patients using cost-effective measures. All 3 patients were extubated within 72 hours after CA, and 2 patients were discharged home with good neurological outcome.

CONCLUSION

Adoption of an evidence-based hypothermia protocol for adult CA patients is feasible in the intensive care setting of a university hospital in Pakistan.

IMPLICATIONS

The process used in the project can serve as a road map to other hospitals in resource-limited countries such as Pakistan that are motivated to improve post-CA outcomes. This experience reveals that advanced practice nurses can be instrumental in translation of evidence into practice in a healthcare system in Pakistan.

Prophylactic antibiotics are associated with a lower incidence of pneumonia in cardiac arrest survivors treated with targeted temperature management

INTRODUCTION

Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients with structural brain injury, but have not been examined in cardiac arrest survivors undergoing targeted temperature management (TTM). We investigated the effect of PRO on the development of pneumonia in that population.

METHODS

We conducted a retrospective cohort study comparing patients treated with PRO to those not receiving PRO (no-PRO) using Northern Hypothermia Network registry data. Cardiac arrest survivors ≥ 18 years of age with a GCS<8 at hospital admission and treated with TTM at 32-34 °C were enrolled in the registry. Differences were analyzed in univariate analyses and with logistic regression models to evaluate independent associations of clinical factors with incidence of pneumonia and good functional outcome.

RESULTS

416 of 1240 patients (33.5%) received PRO. Groups were similar in age, gender, arrest location, initial rhythm, and time from collapse to return of spontaneous circulation. PRO patients had less pneumonia (12.6% vs. 54.9%, p < 0.001) and less sepsis (1.2 vs. 5.7%, p < 0.001) compared to no-PRO patients. ICU length of stay (98 vs. 100 h, p = 0.2) and incidence of a good functional outcome (41.1 vs. 36.6%, p = 0.19) were similar between groups. Backwards stepwise logistic regression demonstrated PRO were independently associated with a lower incidence of pneumonia (OR 0.09, 95% 0.06-0.14, p < 0.001) and a similar incidence of good functional outcome.

CONCLUSIONS

Prophylactic antibiotics were associated with a reduced incidence of pneumonia but a similar rate of good functional outcome.

Fulfilling caloric demands according to indirect calorimetry may be beneficial for post cardiac arrest patients under therapeutic hypothermia

INTRODUCTION

We sought to investigate the energy requirements for patients under therapeutic hypothermia, and the relationship of energy fulfillment to patient outcome.

PATIENTS AND METHODS

Adult patients admitted to our ICU after successful resuscitation from cardiac arrest for post resuscitation therapeutic hypothermia from April, 2012 to March, 2014 were enrolled. Body temperature was managed using the surface cooling device (Arctic Sun(®), IMI). Calorimeter module on the ventilator (Engström carestation(®), GE) was used for indirect calorimetry. Energy expenditure (EE) and respiratory quotient (RQ) were recorded continuously, as the average of the recent 2h. Measurements were started at the hypothermic phase and continued until the rewarming was completed. Cumulative energy deficit was calculated as the sum of difference between EE and daily energy provision for the 4 days during hypothermia therapy.

RESULTS

Seven patients were eligible for analysis. Median EE for the hypothermic phase (day 1) was 1557.0kcald(-1). EE was elevated according with the rise in body temperature, reaching 2375kcald(-1) at normothermic phase. There was significant association between cumulative energy deficit and the length of ICU stay, among patients with good neurologic recovery (cerebral performance category (CPC): 1-3).

CONCLUSION

The EE for patients under therapeutic hypothermia was higher than expected. Meeting the energy demand may improve patient outcome, as observed in the length of ICU stay for the present study. A larger, prospective study is awaited to validate the results of our study.

Adipose-derived mesenchymal stem cells reduce neuronal death after transient global cerebral ischemia through prevention of blood-brain barrier disruption and endothelial damage

Global cerebral ischemia (GCI) is the leading cause of a poor prognosis even after successful resuscitation from cardiac arrest. Therapeutic induction of hypothermia (TH) is the only proven therapy-and current standard care-for GCI after cardiac arrest; however, its application has been significantly limited owing to technical difficulties. Mesenchymal stem cells (MSCs) are known to suppress neuronal death after cerebral ischemia. The prevention of blood-brain barrier (BBB) disruption has not been suggested as a mechanism of MSC treatment but has for TH. We evaluated the therapeutic effect of MSC administration on BBB disruption and neutrophil infiltration after GCI. To evaluate the therapeutic effects of MSC treatment, rats were subjected to 7 minutes of transient GCI and treated with MSCs immediately after reperfusion. Hippocampal neuronal death was evaluated at 7 days after ischemia using Fluoro-Jade B (FJB). BBB disruption, endothelial damage, and neutrophil infiltration were evaluated at 7 days after ischemia by immunostaining for IgG leakage, Rat endothelial antigen-1, and myeloperoxidase (MPO). Rats treated with MSCs showed a significantly reduced FJB+ neuron count compared with the control group. They also showed reduced IgG leakage, endothelial damage, and MPO+ cell counts. The present study demonstrated that administration of MSCs after transient GCI provides a dramatic protective effect against hippocampal neuronal death. We hypothesized that the neuroprotective effects of MSC treatment might be associated with the prevention of BBB disruption and endothelial damage and a decrease in neutrophil infiltration.

Therapeutic temperature management after cardiac arrest and the risk of bleeding: systematic review and meta-analysis

AIM

Prognosis after cardiac arrest in the era of modern critical care is still poor with a high mortality of approximately 90%. Around 30% of the survivors have neurological impairments. Targeted temperature management (TTM) is the only treatment option which can improve mortality and neurological outcome. It is so far unclear if bleeding complications occur more often in patients undergoing TTM treatment.

METHODS

We conducted a systematic literature research in September 2013 including three major databases i.e. MEDLINE, EMBASE and CENTRAL. All studies were rated in respect to the ILCOR Guidelines and concerning their level of evidence and quality. We then performed a meta-analysis on bleeding disposition under TTM.

RESULTS

We initially found 941 studies out of which 34 matched our requirements and were thus included in our overview. Five studies including 599 patients were summarized in a meta-analysis concerning bleeding complications of all severities. There was a trend toward higher bleeding in patients treated with TTM (RR: 1.30, 95% CI: 0.97-1.74) which did not reach significance (p=0.085). Seven studies with an overall 599 patients were included in our meta-analysis on bleeding requiring transfusion. There was no significant difference in the incidence of severe bleeding with a risk ratio of 0.97 (95% CI: 0.61-1.56, p=0.909).

CONCLUSIONS

The data included in our meta-analysis indicate that, concerning the risk of bleeding, TTM is a safe method for patients after cardiac arrest. We did not observe a significantly higher risk for bleeding in patients undergoing TTM.

Therapeutic hypothermia and the risk of infection: a systematic review and meta-analysis

OBJECTIVE

Observational studies suggest that infections are a common complication of therapeutic hypothermia. We performed a systematic review and meta-analysis of randomized trials to examine the risk of infections in patients treated with hypothermia.

DATA SOURCES

PubMed, Embase, and the Cochrane Central Register of Controlled Trials were systematically searched for eligible studies up to October 1, 2012.

STUDY SELECTION

We included randomized controlled clinical trials of therapeutic hypothermia induced in adults for any indication, which reported the prevalence of infection in each treatment group.

DATA EXTRACTION

For each study, we collected information about the baseline characteristics of patients, cooling strategy, and infections.

DATA SYNTHESIS

Twenty-three studies were identified, which included 2,820 patients, of whom 1,398 (49.6%) were randomized to hypothermia. Data from another 31 randomized trials, involving 4,004 patients, could not be included because the occurrence of infection was not reported with sufficient detail or not at all. The risk of bias in the included studies was high because information on the method of randomization and definitions of infections lacked in most cases, and assessment of infections was not blinded. In patients treated with hypothermia, the prevalence of all infections was not increased (rate ratio, 1.21 [95% CI, 0.95-1.54]), but there was an increased risk of pneumonia and sepsis (risk ratios, 1.44 [95% CI, 1.10-1.90]; 1.80 [95% CI, 1.04-3.10], respectively).

CONCLUSION

The available evidence, subject to its limitations, strongly suggests an association between therapeutic hypothermia and the risk of pneumonia and sepsis, whereas no increase in the overall risk of infection was observed. All future randomized trials of hypothermia should report on this important complication.

Post-resuscitation care for survivors of cardiac arrest

Cardiac arrest can occur following a myriad of clinical conditions. With advancement of medical science and improvements in Emergency Medical Services systems, the rate of return of spontaneous circulation for patients who suffer an out-of-hospital cardiac arrest (OHCA) continues to increase. Managing these patients is challenging and requires a structured approach including stabilization of cardiopulmonary status, early consideration of neuroprotective strategies, identifying and managing the etiology of arrest and initiating treatment to prevent recurrence. This requires a closely coordinated multidisciplinary team effort. In this article, we will review the initial management of survivors of OHCA, highlighting advances and ongoing controversies.

Bullous Lesions After Use of a Commercial Therapeutic Hypothermia Temperature Management System: A Possible Burn Injury?

Therapeutic hypothermia (TH) is a novel technique for improving the likelihood of survival with good neurologic outcome after cardiopulmonary arrest. While commercial temperature management systems (TMS) are intended to facilitate cooling of the body during TH, their operation also involves body exposure to heat. We describe the case of a 72-year-old female postarrest patient who underwent TH using a commercial water-circulating TMS and concurrent continuous renal replacement therapy. The patient developed bullous lesions on the thigh and torso suspected to constitute a scald burn injury from the TMS. Clinicians must be aware of this important adverse event when providing TH, especially in the setting of concurrent hemodialysis therapy.

Invasive versus non-invasive cooling after in- and out-of-hospital cardiac arrest: a randomized trial

INTRODUCTION

Mild induced hypothermia (MIH) is indicated for comatose survivors of sudden cardiac arrest (SCA) to improve clinical outcome. In this study, we compared the efficacy of two different cooling devices for temperature management in SCA survivors.

METHODS

Between April 2008 and August 2009, 80 patients after survived in-hospital (IHCA) and out-of-hospital cardiac arrest (OHCA) were included in this prospective, randomized, single center study. Hypothermia was induced after randomization by either invasive Coolgard(®) cooling or non-invasive ArcticSun(®) surface cooling at 33.0 °C core body temperature for 24 h followed by active rewarming. The primary endpoint was defined as the efficacy of both cooling systems, measured by neuron-specific enolase (NSE) levels as a surrogate parameter for brain damage. Secondary efficacy endpoints were the clinical and neurological outcome, time to start of cooling and reaching the target temperature, target temperature-maintenance and hypothermia-associated complications.

RESULTS

NSE at 72 h did not differ significantly between the 2 groups with 16.5 ng/ml, interquartile range 11.8-46.5 in surface-cooled patients versus 19.0 ng/ml, interquartile range 11.0-42.0 in invasive-cooled patients, p = 0.99. Neurological and clinical outcome was similar in both groups. Target temperature of 33.0 °C was maintained more stable in the invasive group (33.0 versus 32.7 °C, p < 0.001). Bleeding complications were more frequent with invasive cooling (n = 17 [43.6 %] versus n = 7 [17.9 %]; p = 0.03).

CONCLUSION

Invasive cooling has advantages with respect to temperature management over surface cooling; however, did not result in different outcome as measured by NSE release in SCA survivors. Bleeding complications were more frequently encountered by invasive cooling.

Therapeutic hypothermia associated with increased survival after resuscitation in children

Brain injury after resuscitation is associated with high morbidity and mortality in children. Therapeutic hypothermia has theoretical benefits on brain preservation. It has been shown to be effective in improving neurological outcomes after adult ventricular arrhythmia-induced cardiac arrest and neonatal asphyxia. However, there have only been a few reports about therapeutic hypothermia after pediatric resuscitation. We conducted this retrospective cohort study in a tertiary pediatric intensive care unit between January 2010 and June 2012. All children from 2 months to 18 years of age with resuscitation and a history of at least 3 minutes of chest compressions with survival for 12 hours or more after return of circulation were eligible. Forty-three patients met the eligibility criteria for the study. Forty-two patients (97.6%) were asphyxial in etiology; 29 (67.4%) of them occurred out-of-hospital. Excluding one child with cardiac etiology, the overall survival rate to hospital discharge was 57.1%. Fourteen (33.3%) patients received hypothermia therapy and were cooled to 33°C for 72 hours. The survival rate was higher in the therapeutic hypothermia group (11/14, 78.6%) than in the normothermia group (13/28, 46.4%). In conclusion, therapeutic hypothermia was associated with increased survival rate after pediatric resuscitation.

Delayed treatment with hypothermia protects against the no-reflow phenomenon despite failure to reduce infarct size

BACKGROUND

Many studies have shown that when hypothermia is started after coronary artery reperfusion (CAR), it is ineffective at reducing necrosis. However, some suggest that hypothermia may preferentially reduce no-reflow. Our aim was to test the effects of hypothermia on no-reflow when initiated close to reperfusion and 30 minutes after reperfusion, times not associated with a protective effect on myocardial infarct size.

METHODS AND RESULTS

Rabbits received 30 minutes coronary artery occlusion/3 hours CAR. In protocol 1, hearts were treated for 1 hour with topical hypothermia (myocardial temperature ≈32°C) initiated at 5 minutes before or 5 minutes after CAR, and the results were compared with a normothermic group. In protocol 2, hypothermia was delayed until 30 minutes after CAR and control hearts remained normothermic. In protocol 1, risk zones were similar and infarct size was not significantly reduced by hypothermia initiated close to CAR. However, the no-reflow defect was significantly reduced by 43% (5 minutes before CAR) and 38% (5 minutes after CAR) in hypothermic compared with normothermic hearts (P=0.004, ANOVA, P=ns between the 2 treated groups). In protocol 2, risk zones and infarct sizes were similar, but delayed hypothermia significantly reduced no-reflow in hypothermic hearts by 30% (55±6% of the necrotic region in hypothermia group versus 79±6% with normothermia, P=0.008).

CONCLUSION

These studies suggest that treatment with hypothermia reduces no-reflow even when initiated too late to reduce infarct size and that the microvasculature is especially receptive to the protective properties of hypothermia and confirm that microvascular damage is in large part a form of true reperfusion injury.

Pyrexia and neurologic outcomes after therapeutic hypothermia for cardiac arrest

OBJECTIVE

Therapeutic hypothermia, also known as targeted temperature management (TTM), improves clinical outcomes in patients resuscitated from cardiac arrest. Hyperthermia after discontinuation of active temperature management ("rebound pyrexia") has been observed, but its incidence and association with clinical outcomes is poorly described. We hypothesized that rebound pyrexia is common after rewarming in post-arrest patients and is associated with poor neurologic outcomes.

METHODS

Retrospective multicenter US clinical registry study of post-cardiac arrest patients treated with TTM at 11 hospitals between 5/2005 and 10/2011. We assessed the incidence of rebound pyrexia (defined as temperature >38°C) in post-arrest patients treated with TTM and subsequent clinical outcomes of survival to discharge and "good" neurologic outcome at discharge, defined as cerebral performance category (CPC) 1-2.

RESULTS

In this cohort of 236 post-arrest patients treated with TTM, mean age was 58.1 ± 15.7 y and 106/236 (45%) were female. Of patients who survived at least 24h after TTM discontinuation (n=167), post-rewarming pyrexia occurred in 69/167 (41%), with a median maximum temperature of 38.7 (IQR 38.3-38.9). There were no significant differences between patients experiencing any pyrexia and those without pyrexia regarding either survival to discharge (37/69 (54%) v 51/98 (52%), p=0.88) or good neurologic outcomes (26/37 (70%) v 42/51 (82%), p=0.21). We compared patients with marked pyrexia (greater than the median pyrexia of 38.7°C) versus those who experienced no pyrexia or milder pyrexia (below the median) and found that survival to discharge was not statistically significant (40% v 56% p=0.16). However, marked pyrexia was associated with a significantly lower proportion of CPC 1-2 survivors (58% v 80% p=0.04).

CONCLUSIONS

Rebound pyrexia occurred in 41% of TTM-treated post-arrest patients, and was not associated with lower survival to discharge or worsened neurologic outcomes. However, among patients with pyrexia, higher maximum temperature (>38.7°C) was associated with worse neurologic outcomes among survivors to hospital discharge.

A prospective, randomized trial of continuous lateral rotation ("kinetic therapy") in patients with cardiogenic shock

BACKGROUND

Continuous lateral rotation ["Kinetic therapy" (KT)] has been shown to reduce complications and to shorten hospital stay in trauma patients. Data in non-surgical patients is inconclusive. Retrospective data suggest a beneficial effect of KT in patients with cardiogenic shock (CS) requiring ventilator therapy. KT, however, has not been tested prospectively in those patients.

METHODS

A prospective, randomized, open-label trial was performed to compare KT using oscillating beds (TryaDyne Proventa, KCI) with standard care (SC). Patients with cardiogenic shock requiring ventilator therapy for more than 24 h were included. Primary endpoint was the occurrence of hospital-acquired pneumonia. Secondary endpoints were the occurrence of pressure ulcers during the hospital stay and 1-year all-cause mortality.

RESULTS

Forty-five patients were randomized to KT, and 44 to SC. All patients required at least one inotropic agent and one vasopressor for circulatory assistance. The groups were comparable in the etiology of heart disease, in the use of revascularization procedures, the use of balloon counterpulsation, and APACHE-II score (33 ± 5 vs. 33 ± 4) and SOFA score (11 ± 1 vs. 11 ± 1) at inclusion; however, more patients in SC were subject to resuscitation before inclusion. Hospital-acquired pneumonia occurred in 10 patients in KT and 28 patients in SC (p < 0.001); pressure ulcers were seen in 10 versus 2 patients (p < 0.001). Hospital mortality tended to be lower in KT, and 1-year all-cause mortality was 41 % in KT and 66 % in SC (p = 0.028).

CONCLUSION

The use of KT reduces rates of pneumonia and pressure ulcers as compared to SC. Moreover, in this study, patients with KT had a better outcome. The study suggests that KT should be used in patients with cardiogenic shock requiring ventilator therapy for a prolonged time.

Strategies for reducing the incidence of skin complications in newborns treated with whole-body hypothermia

OBJECTIVE

To present the results of a strategy designed to reduce the incidence of skin complications in newborns with hypoxic-ischemic encephalopathy treated with moderate whole-body hypothermia.

DESIGN

Retrospective study.

SETTING

Neonatal Intensive Care Unit (NICU).

PATIENTS

Thirty-nine neonates cooled in the considered period.

INTERVENTION

Starting from January 2008, for neonates treated with moderate whole-body hypothermia (33.5 °C), the cooling system was set in "automatic servo-controlled mode (ACM)", where the temperature of the circulating water could vary between 4 °C and 42 °C. Starting from January 2009, cooling blankets were used in another type of automatic mode, the "gradient variable mode (GVM)", where the circulating water was maintained at a specific pre-set gradient towards the patient's body temperature, and a specific nursing protocol (NP) was adopted.

MEASUREMENTS AND MAIN RESULTS

Two of the eleven newborns treated with the "ACM" exhibited skin complications compatible with subcutaneous fat necrosis (SFN). None of the twenty-eight newborns treated with the "GVM" exhibited skin complications. A comparison of the biochemical and hematological data between these two groups revealed that newborns treated after the adopting of a NP and the "GVM" showed lower serum protein C and calcium levels, and higher platelet levels.

CONCLUSIONS

Our data suggest that newborns undergoing therapeutic cooling may benefit from a specific NP and correct cooling unit setting. Should further studies confirm our data, this nursing approach could be easily adopted.