Temperature Management In Patients Research Articles

Optimal Targeted Temperature Management for Patients with Post-Cardiac Arrest Syndrome.

Background: To prevent hypoxic-ischemic brain damage in patients with post-cardiac arrest syndrome (PCAS), international guidelines have emphasized performing targeted temperature management (TTM). However, the most optimal targeted core temperature and cooling duration reached no consensus to date. This study aimed to clarify the optimal targeted core temperature and cooling duration, selected according to the time interval from collapse to return of spontaneous circulation (ROSC) in patients with PCAS due to cardiac etiology. Methods: Between 2014 and 2020, the targeted core temperature was 34 °C or 35 °C, and the cooling duration was 24 h. If the time interval from collapse to ROSC was within 20 min, we performed the 35 °C targeted core temperature (Group A), and, if not, we performed the 34 °C targeted core temperature (Group B). Between 2009 and 2013, the targeted core temperature was 34 °C, and the cooling duration was 24 or 48 h. If the interval was within 20 min, we performed the 24 h cooling duration (Group C), and, if not, we performed the 48 h cooling duration (Group D). Results: The favorable neurological outcome rates at 30 days following cardiac arrest were 45.7% and 45.5% in Groups A + B and C + D, respectively (p = 0.977). In patients with ROSC within 20 min, the favorable neurological outcome rates at 30 days following cardiac arrest were 75.6% and 86.4% in Groups A and C, respectively (p = 0.315). In patients with ROSC ≥ 21 min, the favorable neurological outcome rates at 30 days following cardiac arrest were 29.3% and 18.2% in Groups B and D, respectively (p = 0.233). Conclusions: Selecting the optimal target core temperature and the cooling duration for TTM, according to the time interval from collapse to ROSC, may be helpful in patients with PCAS due to cardiac etiology.

Targeted Temperature Management for Patients with Acute Ischemic Stroke: A Literature Review.

Despite significant advances in medical imaging, thrombolytic therapy, and mechanical thrombectomy, acute ischemic strokes (AIS) remain a major cause of mortality and morbidity globally. Targeted temperature management (TTM) has emerged as a potential therapeutic intervention, aiming to mitigate neuronal damage and improve outcomes. This literature review examines the efficacy and challenges of TTM in the context of an AIS. A comprehensive literature search was conducted using databases such as PubMed, Cochrane, Web of Science, and Google Scholar. Studies were selected based on relevance and quality. We identified key factors influencing the effectiveness of TTM such as its timing, depth and duration, and method of application. The review also highlighted challenges associated with TTM, including increased pneumonia rates. The target temperature range was typically between 32 and 36 °C, with the duration of cooling from 24 to 72 h. Early initiation of TTM was associated with better outcomes, with optimal results observed when TTM was started within the first 6 h post-stroke. Emerging evidence indicates that TTM shows considerable potential as an adjunctive treatment for AIS when implemented promptly and with precision, thereby potentially mitigating neuronal damage and enhancing overall patient outcomes. However, its application is complex and requires the careful consideration of various factors.

Abstract 431: Targeted Temperature Management for Patients With Out-of-Hospital Cardiac Arrest and Prolonged Mechanical Ventilation Period: Insight From the National Inpatient Sample Database 2019

Introduction: The TTM2 trial showed that targeted temperature management (TTM) did not improve the functional status of survivors of out-of-hospital cardiac arrest (OHCA). However, the TTM2 trial OHCA survivors cohort had short mechanical ventilation (MV) duration (3.8 days in the hypothermic group and 2.9 days in the normothermic group). Aims: We aimed to investigate the functional status of OHCA survivors who required a prolonged MV duration. Methods: We utilized the National Inpatient Sample Database 2019. Participants were included if they were primarily admitted for cardiac arrest regardless of initial rhythm. Prolonged MV was defined as > 4 days. Patients who have ICD-10 codes for both short and prolonged MV durations were excluded as they potentially had multiple intubations. The primary outcome was discharge from the hospital to home, as a surrogate for good functional status on discharge. Results: A total of 28,890 patients were admitted for cardiac arrest in 2019 in the United States. Of them, 67.5% (n=19,515) had MV. Of the mechanically ventilated patients, 74.3% (n=14,490) were ventilated for ≤ 4 days, 24.8% (n=4,835) had prolonged MV, and 190 admissions were excluded for possible multiple MV episodes. TTM utilization was comparable between survivors with prolonged MV (8.7%, n=200) and short MV (7.6%, n=380)(p=0.083). Discharge to home was higher in the short MV group [33.8% (n=1,690) vs 15% (n=345), p<0.001]. After adjusting for age, sex, race, insurance, Elixhauser comorbidity index, renal replacement therapy, and coronary angiography, TTM was not independently associated with discharge to home in the short MV group (aOR 0.951, 95% CI 1.008-0.795, p=0.992). However, TTM was associated with significantly higher odds of discharge to home in the prolonged MV group (aOR 2.441, 95% CI 1.591-3.744, p<0.001). Conclusions: One-fourth of the OHCA survivors, mechanically ventilated, cohort required prolonged MV. These patients have poorer functional status (discharge to home rate) that the short MV cohort. TTM seems to correlate with improved adjusted functional status on discharge from the hospital in the prolonged MV group. Future clinical trials should investigate the TTM impact on this subgroup of OHCA survivors.

Abstract 412: Targeted Temperature Management for Patients With Out of Hospital Cardiac Arrest: A Comparison of the TTM2 Trial Population With Real World Data

Introduction: The TTM2 trial demonstrated no improvement of the functional status in survivors of Out-of-Hospital Cardiac Arrest (OHCA). However, the external validitiy of the trial remains to be investigated. Aim: We aimed to compare the patient population of the TTM2 trial to the real world data. Methods: We obtained the data from multiple national registries including Cardiac Arrest Registry to Enhance Survival (CARES), the Australasian Resuscitation Outcomes Consortium (Aus-ROC), the Danish Cardiac Arrest Registry (DCAR), and the Swedish Cardiopulmonary Resuscitation Registry (SCRR). We pooled the data from these registries and compared them to the data from the TTM2 trial. Results: We identified a total of 262,482 encounters from all the databases and 1,861 encounters from the TTM2 trial. The average age was comparable between both groups (64 years), females gender (registries 35% vs trial 20%), arrest event happened at the place of residence (registries 72% vs trial 53%), Bystander-witnessed arrest (registries 57% vs trial 91%), Bystander-performed CPR (registries 38% vs trial 80%), initial shockable rhythm (registries 25% vs trial 74%), non-shockable rhythm (registries 75% vs trial 26%). Conclusion: Large discrepancies were identified between the data from the TTM2 and the pooled data obtained from multiple registries. This needs to be further investigated.

The importance of peri-anaesthetic temperature management: part 2

When considering patient temperature management under anaesthesia, hyperthermia is a rare complication. Associated risk factors, management and prevention of hyperthermia are considered in this article to ensure that veterinary nurses feel confident in dealing with these cases and identifying atrisk patients. This article is the second in a series dedicated to exploring the importance of temperature monitoring and management during the anaesthetic period.

Targeted temperature management in patients with intracerebral haemorrhage, subarachnoid haemorrhage, or acute ischaemic stroke: updated consensus guideline recommendations by the Neuroprotective Therapy Consensus Review (NTCR) group

BackgroundThere is a lack of consistent, evidence-based guidelines for the management of patients with fever after brain injury. The aim was to update previously published consensus recommendations on targeted temperature management after intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and acute ischaemic stroke in patients who require admission to critical care. MethodsA modified Delphi consensus, the Neuroprotective Therapy Consensus Review (NTCR), included 19 international neuro-intensive care experts with a subspecialty interest in the acute management of intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and acute ischaemic stroke. An online, anonymised survey was completed ahead of the meeting before the group came together to consolidate consensus and finalise recommendations on targeted temperature management. A threshold of ≥80% for consensus was set for all statements. ResultsRecommendations were formulated based on existing evidence, literature review, and consensus. After intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and acute ischaemic stroke in patients who require critical care admission, core temperature should ideally be monitored continuously and maintained between 36.0°C and 37.5°C using automated feedback-controlled devices, where possible. Targeted temperature management should be commenced within 1 h of first fever identification with appropriate diagnosis and treatment of infection, maintained for as long as the brain remains at risk of secondary injury, and rewarming should be controlled. Shivering should be monitored and managed to limit risk of secondary injury. Following a single protocol for targeted temperature management across intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and acute ischaemic stroke is desirable. ConclusionsBased on a modified Delphi expert consensus process, these guidelines aim to improve the quality of targeted temperature management for patients after intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and acute ischaemic stroke in critical care, highlighting the need for further research to improve clinical guidelines in this setting.

Targeted temperature management in brain edema

Background: Targeted temperature management is a treatment strategy to lower core body temperature to achieve neuroprotection or reduce elevated intracranial pressure. Therefore, it has been increasingly used in the neurointensive care unit to manage various types of acute neurologic injuries.Current Concepts: Targeted temperature management can be divided into three distinct phases, including induction, maintenance, and rewarming, and each phase has risks and predictable complications. In patients with acute neurocritical illnesses, including traumatic brain injury, subarachnoid hemorrhage, intracranial hemorrhage, and ischemic stroke, brain edema is a potentially life-threatening complication as it raises the intracranial pressure, leading to brain herniation and permanent neurological damage. In this sense, targeted temperature management can be considered the final strategy for medical treatment for controlling an intracranial pressure crisis in patients with severe brain injury.Discussion and Conclusion: In the neurointensive care unit, applying targeted temperature management to patients with severe brain injuries may be challenging. Targeted temperature management in critically ill neurological patients is associated with an increased risk of systemic complications, as hypothermia is prolonged, requiring a comprehensive patient-by-patient assessment of the advantages and disadvantages of treatment. Except for cerebral pressure management, analyses of targeted temperature management in patients with traumatic brain injury and subarachnoid hemorrhage remain controversial regarding its effect on prognosis. Targeted temperature management should be reserved for selective patients, and further studies are needed to improve the efficacy of hypothermia for individual conditions, including intracerebral hemorrhage and ischemic stroke.

Changes in Practice of Controlled Hypothermia After Cardiac Arrest in the Past 20 Years - A Critical Care Perspective.

For 20 years induced hypothermia and targeted temperature management (TTM) have been recommended to mitigate brain injury and increase survival after cardiac arrest. Based on animal research and small clinical trials the International Liaison Committee on Resuscitation strongly advocated hypothermia at 32-34°C for 12-24 hours for comatose out-of-hospital cardiac arrest patients with initial rhythm ventricular fibrillation or non-perfusing ventricular tachycardia. The intervention was implemented world-wide. The last decade hypothermia and TTM have been investigated in larger clinical randomized trials with focus on target temperature depth, target temperature duration, pre-hospital initiation versus in-hospital initiation, in non-shockable rhythms, and in in-hospital cardiac arrests. Systematic reviews suggest little or no effect of delivering the intervention based on the summary of evidence and ILCOR today recommends to only treat fever and keep temperatures below 37.5°C (weak recommendation, low certainty evidence). Here we describe the evolution of temperature management for cardiac arrest patients during the last 20 years and how the accrued evidence has influenced not only the recommendations but also the guideline process. We also discuss possible paths forward in this field, both bringing up whether fever management at all is beneficial for cardiac arrest patients, and which knowledge gaps future clinical trials in temperature management should address.

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.

Temperature Management in Patients After Cardiac Arrest


 Two systematic reviews (1 with a network meta-analysis and 1 with a meta-analysis), 1 randomized controlled trial, and 7 non-randomized studies were identified about the comparative clinical effectiveness of normothermia versus hypothermia in adult patients after cardiac arrest.
 Normothermia was found to be similar to hypothermia for several clinical- and patient-related outcomes, such as survival, hospital mortality, and quality of life. There was limited evidence to suggest that either type of targeted temperature management was more efficacious, with findings suggesting that normothermia may be associated with greater protocol adherence and decreased prescription medication use coming from low-quality non-randomized studies.
 Four evidence-based guidelines were identified regarding targeted temperature management (normothermia or hypothermia) in adult patients after cardiac arrest. All guidelines strongly recommend targeted temperature management for eligible patients, particularly for patients resuscitated following out-of-hospital cardiac arrest. Identified guidelines from the Canadian Cardiovascular Society and American Academy of Neurology present strong recommendations for hypothermic targeted temperature management.

The intensity of extremely low frequency electromagnetic field by target temperature of MEGAWARMERⓇ patient temperature management system

Background: Extremely low frequency electromagnetic field (ELF-EMF) emitted by electronic devices is associated with various biological effects on the human body. MEGAWARMERⓇ patient temperature management system (PTMS) is widely used for the patient temperature management in anesthesia and critical care. We investigated the intensity of ELF-EMF according to the distance and target temperature of MEGAWARMERⓇ PTMS to find the distance allowing minimized exposure to ELF-EMF. Methodology: This study was a prospective experimental study. Target temperature was set at 31℃, 36℃ and 41℃. After setting each target temperature, the intensity of ELF-EMF was measured 300 times during 10 min at interval of 2 sec, at distances of 15, 30, and 45 cm from the MEGAWARMERⓇ PTMS, respectively. Nine measurement groups from 3 different target temperatures and 3 different distances resulted in 2700 data. Including background EMF intensity with the MEGAWARMERⓇ PTMS also turned off, total 3000 data in 10 groups were collected. Results: At the distance of 15 cm from the MEGAWARMERⓇ PTMS, mean values of ELF-EMF were 4.6721 milligauss (mG), where 1 G is equivalent to 10⁻⁴ Tesla (T) (or 1 mG = 0.1 μT) at 31℃, 4.2852 mG at 36℃, and 3.9935 mG at 41℃. At the distance of 30 cm, mean values of ELF-EMF were 2.0948 mG at 31℃, 2.0790 mG at 36℃, and 2.0633 mG at 41℃. At the distances of 15 cm and 30 cm, the lower target temperature showed statistically significantly higher mean values of ELF-EMF (p < 0.05). In all three target temperatures, longer distance made statistically significantly lower mean value of ELF-EMF (p < 0.05). Conclusions: The mean intensity of ELF-EMF from the MEGAWARMERⓇ Patient Temperature Management at the distance of 15 cm and 30 cm exceeded 2 mG recommended by Swedish Confederation of Professional Employees guideline. Key words: Extremely low frequency electromagnetic field; Temperature management; Intensive care unit Abbreviations: ELF-EMF– Extremely Low Frequency ElectroMagnetic Field; PRMS – Patient Temperature Management System; mG – milligauss Citation: Kim SH, Park YH, Lee H, Lee SE, Park JH, Lee KH, Kim YH. The intensity of extremely low frequency electromagnetic field by target temperature of MEGAWARMERⓇ patient temperature management system. Anaesth. pain intensive care 2021;25(6):741-745; DOI: 10.35975/apic.v25i6.1693 Received: August 11, 2021, Reviewed: September 30, 2021, Accepted: October 6, 2021

Pursuit of Optimal Targeted Temperature Management for Patients With Out-of-Hospital Cardiac Arrest.

Pursuit of Optimal Targeted Temperature Management for Patients With Out-of-Hospital Cardiac Arrest.

Aluminium release and fluid warming: provocational setting and devices at risk

BackgroundFluid warming, recommended for fluid rates of > 500 ml h-1, is an integral part of patient temperature management strategies. Fluid warming devices using an uncoated aluminium containing heating element have been reported to liberate aluminium resulting in critical aluminium concentrations in heated fluids. We investigated saline solution (0.9%), artificially spiked with organic acids to determine the influence of fluid composition on aluminium release using the uncoated enFlow® device. Additionally, the Level1® as a high volume fluid warming device and the ThermoSens® device were investigated with artificial spiked fluid at high risk for aluminum release and a clinically used crystalloid solution.ResultsSaline solution spiked with lactate more than acetate, especially at a non neutral pH, led to high aluminium release. Next to the enFlow® device, aluminium release was observed for the Level1® device, but not for the coated ThermoSens®-device.ConclusionUncoated aluminium containing fluid warming devices lead to potentially toxic levels of aluminium in heated fluids, especially in fluids with non-neutral pH containing organic acids and their salts like balanced electrolyte solutions.

Outcome Related to Level of Targeted Temperature Management in Postcardiac Arrest Syndrome of Low, Moderate, and High Severities: A Nationwide Multicenter Prospective Registry.

The optimal target temperature during targeted temperature management for patients after cardiac arrest remains under debate. The aim of this study was to evaluate the association between targeted temperature management at lower target temperatures and the neurologic outcomes among patients classified by the severity of postcardiac arrest syndrome. A multicenter observational study from the out-of-hospital cardiac arrest registry of the Japanese Association for Acute Medicine, which is a nationwide prospective registry of out-of-hospital cardiac arrest patients. A total of 125 critical care medical centers or hospitals with an emergency care department across Japan. A total of 1,111 out-of-hospital cardiac arrest patients who had received targeted temperature management. We divided all 1,111 postcardiac arrest syndrome patients treated with targeted temperature management into two groups: those who received targeted temperature management at a lower target temperature (33-34°C) and those who received targeted temperature management at a higher target temperature (35-36°C). In regard to classification of the patients, we divided the patients into three categories of severity (low, moderate, and high severities) using the risk classification tool, post-Cardiac Arrest Syndrome for Therapeutic hypothermia, which was previously validated. The primary outcome was the percentage of patients with a good neurologic outcome at 30 days, and the secondary outcome was the survival rate at 30 days. Multivariate analysis showed that targeted temperature management at 33-34°C was significantly associated with a good neurologic outcome and survival at 30 days in the moderate severity (odds ratio, 1.70 [95% CI, 1.03-2.83] and 1.90 [95% CI, 1.15-3.16], respectively), but not in the patients of low or high severity (pinteraction = 0.033). Propensity score analysis also showed that targeted temperature management at 33-34°C was associated with a good neurologic outcome in the moderate-severity group (p = 0.022). Targeted temperature management at 33-34°C was associated with a significantly higher rate of a good neurologic outcome in the moderate-severity postcardiac arrest syndrome group, but not in the low- or high-severity group.

Impact of Fever Prevention in Brain-Injured Patients (INTREPID): Study Protocol for a Randomized Controlled Trial

Multiple studies demonstrate that fever/elevated temperature is associated with poor outcomes in patients with vascular brain injury; however, there are no conclusive studies that demonstrate that fever prevention/controlled normothermia is associated with better outcomes. The primary objective of the INTREPID (Impact of Fever Prevention in Brain-Injured Patients) trial is to test the hypothesis that fever prevention is superior to standard temperature management in patients with acute vascular brain injury. INTREPID is a prospective randomized open blinded endpoint study of fever prevention versus usual care in patients with ischemic or hemorrhagic stroke. The fever prevention intervention utilizes the Arctic Sun System and will be compared to standard care patients in whom fever may spontaneously develop. Ischemic stroke, intracerebral hemorrhage or subarachnoid hemorrhage patients will be included within disease-specific time-windows. Both awake and sedated patients will be included, and treatment is initiated immediately upon enrollment. Eligible patients are expected to require intensive care for at least 72h post-injury, will not be deemed unlikely to survive without severe disability, and will be treated for up to 14days, or until deemed ready for discharge from the ICU, whichever comes first. Fifty sites in the USA and worldwide will participate, with a target enrollment of 1176 patients (1000 evaluable). The target temperature is 37.0°C. The primary efficacy outcome is the total fever burden by °C-h, defined as the area under the temperature curve above 37.9°C. The primary secondary outcome, on which the sample size is based, is the modified Rankin Scale Score at 3months. All efficacy analyses including the primary and key secondary endpoints will be primarily based on an intention-to-treat population. Analysis of the as-treated and per protocol populations will also be performed on the primary and key secondary endpoints as sensitivity analyses. The INTREPID trial will provide the first results of the impact of a pivotal fever prevention intervention in patients with acute stroke ( www.clinicaltrials.gov ; NCT02996266; registered prospectively 05DEC2016).

Abstract 259: Outcomes of Targeted Temperature Management in Patients with Out-of-hospital Refractory Ventricular Fibrillation/ventricular Tachycardia Cardiac Arrest

Background: Current guidelines recommend use of targeted temperature management (TTM) with goal between 32 and 36°C for all comatose adult patients with ROSC after cardiac arrest. However, refractory cardiac arrest with prolonged hypoperfusion, may cause passive cooling below goal temperature. The impact of this passive cooling and subsequent cooling strategies remains unknown. This study aims to describe the association between passive intra-arrest cooling and survival in patients suffering refractory VF/VT cardiac arrest treated with the University of Minnesota extracorporeal cardiopulmonary resuscitation (ECPR) protocol. Methods: Between December 2015 and October 2019, consecutive adult patients with refractory VF/VT arrest requiring ongoing CPR were transported by EMS to the CCL where ECPR, coronary angiography, and PCI were performed, as appropriate. TTM was initiated with goal temperature of 34°C unless clinically significant bleeding occurred, where a goal of 36°C was used. Patient and arrest characteristics, temperature data, and survival were collected retrospectively. Results: Data was gathered for 153 consecutive patients transferred for ECPR; 12 were excluded due to death in CCL prior to TTM. Of the remaining patients, 63 (41%) survived to discharge, where 55 (36%) had CPC scores of 1-2. Among deceased patients, 25 died from acute brain death while 47 died from other causes. Patients with CPC 1-2 had an initial temperature of 34.1°C versus 32.7°C in patients developing acute brain death (p=0.002). Survivors had shorter (p=0.0001) CPR time (52 minutes) versus deceased patients (65 minutes). If the initial temperature was below goal, patients were actively warmed to goal due to bleeding risk with ECPR. Survival to hospital discharge with CPC 1-2 was associated with lower peak warming rate compared with acute brain death (0.37°C/hr vs 0.69°C/hr; p=0.014) Conclusions: Survivors with CPC 1-2 after refractory VF/VT cardiac arrest and ECPR have preserved initial temperatures compared to more severe passive cooling in patients with acute brain death. This may be due to shorter duration of CPR. However, patients with acute brain death were noted to have higher peak rate of rewarming during TTM.

Pneumonia and Extracorporeal Cardiopulmonary Resuscitation Followed by Targeted Temperature Management in Patients With Out-of-Hospital Cardiac Arrest - Retrospective Cohort Study.

Background: We examined the association between initiation of extracorporeal cardiopulmonary resuscitation (ECPR) and the incidence of infectious complications, such as pneumonia, sepsis, and bacteremia, after out-of-hospital cardiac arrest (OHCA) in patients who received targeted temperature management (TTM).Methods and Results: This retrospective study used data from hospital medical records of patients with OHCA treated with TTM who had been admitted to St. Luke’s International Hospital between April 2006 and December 2018. The primary endpoint was the association between the type of CPR and the incidence of early onset pneumonia in the intensive care unit (ICU; between 48 h and 7 days of hospitalization). Univariate and multivariate logistic regression analyses were performed for the primary endpoints. After applying the inclusion/exclusion criteria, 254 patients were included in the analyses; of these, 52 were enrolled in the ECPR group, and 202 were enrolled in the CCPR group. Median age was 58 years, 88.5% were male, prophylactic antibiotics were used in 80.3%, and favorable neurological outcomes were observed in 51.9%. On multivariate analysis, ECPR (odds ratio [OR], 2.78; 95% CI: 1.16–6.66; P=0.037) was significantly associated with the development of early onset pneumonia.Conclusions: ECPR was an independent predictor of pneumonia after OHCA in patients who received TTM.

PIN67 BUDGET IMPACT ANALYSIS OF THE IMPLEMENTATION OF A PRESURGICAL WARMING PROTOCOL TO EFFECTIVELY MANAGE SURGICAL PATIENT NORMOTHERMIA

Perform a budget impact analysis from a hospital perspective and estimate the cost savings achieved by adding a presurgical warming protocol to intra-operative warming, using a forced-air warming system to prevent inadvertent perioperative hypothermia (IPH). The one-year time horizon budget impact model is based on a new static decision-tree, modified from a model published by NICE in 2008. Based on IPH rate, the model allows a comparison of different patient temperature management strategies with associated material and adverse consequences costs. The current analysis uses IPH rates measured in a German hospital when implementing active pre-warming plus intra-operative warming versus intra-operative warming only. Adverse consequences of IPH, according to the NICE guidance, are grouped in surgical site infections (SSI), morbid cardiac events (MCE) and other complications, including the need of blood transfusions. The cost of the adverse consequences is monetized via increased length-of-stay (LOS). The model accounts for minor, intermediate and major surgery and four different age groups following German DRG-data to evaluate the relative risk for SSI and MCE. The costs of a bed-day on a surgical ward are derived from WHO estimates. The hypothermia rate from a retrospective study including 7786 patients having a surgery duration of at least 30 minutes under general anesthesia showed an IPH decrease from 12.4% to 5.1% with the introduction of active pre-warming in addition to intra-operative warming. For a hypothetical hospital conducting 1,000 surgical procedures per year (48% minor, 30% intermediate and 22% major), the implementation of pre-warming could result in total annual cost savings of 192,220€, corresponding to 60% direct costs decrease, 300 less hypothermia events and 342 days reduction in attributable LOS. The implementation of pre-warming is a cost saving intervention and should be recommended for effective management of patient normothermia.

P1861Influence of thermal conductivity on esophageal protection with a cooling device during high-power short-duration radiofrequency ablation

Abstract Introduction Recent clinical data show that high-power, short-duration (HPSD) radiofrequency (RF) ablation can result in a similar esophageal injury rate as traditional low-power, long-duration (LPLD) ablation. Existing methods to prevent esophageal injury have yielded mixed results and can result in prolonged procedure time, potentially increasing the incidence of post-operative cognitive dysfunction. A new esophageal cooling device currently available for whole-body temperature modulation is being studied for the prevention of esophageal injury during LPLD RF ablation and cryoablation. We sought to develop a mathematical model of HPSD ablation in order to quantify the capability of this new esophageal cooling device to protect from esophageal injury under high-power conditions. Methods Using a model we developed of HPSD RF ablation in the left atrium, we measured the change in esophageal lesion formation and the depth of lesions (measured as percent transmurality) with the esophageal cooling device in place and operating at a temperature from 5°C to 37°C. Tissue parameters, including thermal conductivity, were set to average values obtained from existing literature, and energy settings were evaluated at 50W for between 5 and 10 seconds, and at 90W for a duration of 4 seconds. Results Esophageal injury as measured by percent transmurality was considerably higher at 50W and 10s duration than at 90W of power with 4s duration, although both settings showed potential for esophageal injury. The protective effect of the esophageal cooling device was evident for both cases, with a greater effect when using 50W for 10s (Figure 1). At the coldest device settings, using a 5 min pre-cooling period also reduced the transmurality of the intended atrial lesions. Esophageal protection in HPSD ablation Conclusions Esophageal cooling with a new patient temperature management device shows protective effects against thermal injury during RF ablation across a range of tissue thermal conductivity, using a variety of high-power settings, including 90W applied for 4 seconds. Adjusting the cooling power by adjusting the circulating water temperature in the device allows for a tailoring of the protective effects to operating conditions. Acknowledgement/Funding Attune Medical

Effect of local skin blood flow during light and medium activities on local skin temperature predictions

The quality of local skin temperature prediction by thermophysiological models depends on the local skin blood flow (SBF) control functions. These equations were derived for low activity levels (0.8-1met) and mostly in sitting or supine position. This study validates and discusses the prediction of foot SBF during activities of 1-3met in male and females, and the effect on the foot skin temperature prediction (ΔTskin,foot) using the thermophysiological simulation model ThermoSEM. The SBF at the foot was measured for ten male and ten female human subjects at baseline and during three activities (sitting, walking at 1km/h, preferred walking around 3km/h). Additional measurements included the energy expenditure, local skin temperatures (Tskin,loc), environmental conditions and body composition. Measured, normalized foot SBF is 2-8 times higher than the simulated SBF during walking sessions. Also, SBF increases are significantly higher in females vs. males (preferred walking: 4.8±1.5 versus 2.7±1.4, P < 0.05). The quality of ΔTskin,foot using the simulated foot SBF is poor (median deviation is -4.8°C, maximumumdeviationis-6°C). Using the measured SBF in ThermoSEM results in an improved local skin temperature prediction (new maximum deviation is -3.3°C). From these data a new SBF model was developed that includes the walking activity level and gender, and improves SBF prediction and ΔTskin,foot of the thermophysiological model. Accurate SBF and local skin temperature predictions are beneficial in optimizing thermal comfort simulations in the built environment, and might also be applied in sport science or patient's temperature management.