Femoro-iliacal artery versus pulmonary artery core temperature measurement during therapeutic hypothermia: an observational study

Accuracy and precision of non-invasive thermometers compared with the pulmonary artery temperature: a cross-sectional study

BACKGROUND

Temperature fluctuations are critical indicators of a patient's condition in intensive care units (ICUs). While invasive methods offer a more reliable measurement of core temperature, they carry greater risks of complications, limiting their use in most situations. This underscores the need for research evaluating the reliability of non-invasive temperature monitoring methods.

OBJECTIVES

This study aimed to assess the accuracy and precision of four non-invasive temperature measurement techniques compared to pulmonary artery temperature, considered the gold standard.

DESIGN AND SETTING

We conducted a cross-sectional clinical study with repeated measures in the ICUs at Hospital das Clínicas da Universidade Federal de Minas Gerais and Hospital Felício Rocho, Belo Horizonte, Brazil.

METHODS

All patients admitted with a pulmonary artery catheter were included. We simultaneously recorded temperatures from the pulmonary artery, axillary area, oral cavity, temporal artery, and tympanic membrane. Bland-Altman plots were employed to assess the agreement between the different temperature measurements.

RESULTS

A total of 48 patients participated, with a mean age of 54 years. Females comprised 66.67% of the sample. Compared to pulmonary artery temperature, the accuracy and precision (mean and standard deviation) of the non-invasive methods were: axillary (-0.42°C, 0.59°C), oral (-0.30°C, 0.37°C), tympanic membrane (-0.21°C, 0.44°C), and temporal artery (-0.25°C, 0.61°C). Notably, in patients with abnormal body temperature (non-normothermic), only oral and tympanic membrane methods maintained their accuracy and precision.

CONCLUSIONS

The non-invasive thermometers evaluated in this study demonstrated acceptable accuracy and precision (within the clinically relevant threshold of 0.5°C) compared to pulmonary artery temperature. Among the non-invasive methods, the tympanic membrane measurement proved to be the most reliable, followed by the oral method.

Agreement of in-ear temperature to core body temperature measures during invasive whole-body cooling for hypothermic circulatory arrest in aortic arch surgery

Targeted temperature management (TTM) with therapeutic hypothermia (TH) during aortic arch surgery requires valid estimations of core body temperature. The ear canal and epitympanic region might be an easy-to-assess, noninvasive site for the read-out of supra-aortic, cerebral temperature. This observational cohort study comparatively investigated in-ear temperature and different core body temperature (cBT) measurements during TTM/TH for moderate hypothermic circulatory arrest (mHCA) in aortic arch surgery. In total 24 patients (mean age of 56.8 ± 17.5 years; six females) were measured using infrared-thermography of the epitympanic region (BTtym), thermistor-based measurements at the esophagus (BTeso; gold standard), at the ear canal (BTear), at the nasopharynx (BTnas), in the bladder (BTves), and in the rectum (BTrec). The data analysis comprised absolute agreement (AA), bias, intraclass correlation coefficient (ICC), and limit of agreement (LoA). The results revealed high AAs of BTtym, BTear, BTnas in reference to BTeso (biases 0.3-0.6 °C), with also excellent ICCs > 0.9. BTves and BTrec showed lower AAs, higher biases of + 2.5 °C to 3.1 °C with moderate ICCs during mHCA. In the phases of rapid temperature changes, the biases and LoAs were higher throughout all BT measurements. Herein, BTtym performed best of all measurement sites. The study informs about the BT dynamics at different body sites during the mHCA procedure. It supports the approach of using minimally invasive in-ear techniques to estimate core body temperature in an intrahospital TTM/TH setting of mHCA.

Agreement of zero-heat-flux thermometry with the oesophageal and tympanic core temperature measurement in patient receiving major surgery

To identify and prevent perioperative hypothermia, most surgical patients require a non-invasive, accurate, convenient, and continuous core temperature method, especially for patients undergoing major surgery. This study validated the precision and accuracy of a cutaneous zero-heat-flux thermometer and its performance in detecting intraoperative hypothermia. Adults undergoing major non-cardiac surgeries with general anaesthesia were enrolled in the study. Core temperatures were measured with a zero-heat-flux thermometer, infrared tympanic membrane thermometer, and oesophagal monitoring at 15-minute intervals. Taking the average value of temperature measured in the tympanic membrane and oesophagus as a reference, we assessed the agreement using the Bland-Altman analysis and linear regression methods. Sensitivity, specificity, and predictive values of detecting hypothermia were estimated. 103 patients and one thousand sixty-eight sets of paired temperatures were analyzed. The mean difference between zero-heat-flux and the referenced measurements was -0.03 ± 0.25 °C, with 95% limits of agreement (-0.52 °C, 0.47 °C) was narrow, with 94.5% of the differences within 0.5 °C. Lin's concordance correlation coefficient was 0.90 (95%CI 0.89-0.92). The zero-heat-flux thermometry detected hypothermia with a sensitivity of 82% and a specificity of 90%. The zero-heat-flux thermometer is in good agreement with the reference core temperature based on tympanic and oesophagal temperature monitoring in patients undergoing major surgeries, and appears high performance in detecting hypothermia.

Measurement of exhaled breath temperature in patients under general anesthesia: A feasibility study

The aim of the present study was to investigate the respiratory parameters that influence the exhaled breath temperature (EBT) and the feasibility of using the latter to monitor the core temperature under general endotracheal anesthesia. A total of 20 patients undergoing abdominal surgery were included in the present study. At the first stage of the experiment, the respiratory rate was adjusted, while the other respiratory parameters [tidal volume, inspiratory and expiratory time ratio (TI:TE), and positive end expiratory pressure (PEEP)] were maintained at a constant level. At the second stage, the tidal volume was adjusted, while the other respiratory parameters were maintained at a constant level. At the third stage, the TI:TE was adjusted, while the other parameters were maintained at a constant level. At the fourth stage, PEEP was adjusted, while the other parameters were maintained at a constant level. In each experiment, the EBT, the maximum temperature of exhaled air in each min, the inhaled air temperature and the nasopharyngeal temperature (T nose) were recorded every min. During the first stage of the experiment, no significant difference was noted in the EBT at different levels of respiratory rate. During the second, third and fourth stage, no significant difference was noted in the EBT at different tidal volumes, TI:TE and PEEP, respectively. The EBT was significantly correlated with the T nose. Overall, the present study demonstrated that the EBT of patients undergoing abdominal surgery under general endotracheal anesthesia was not affected by the examined respiratory parameters and that it could be considered a feasible method of monitoring core temperature.

Insight into the use of tympanic temperature during target temperature management in emergency and critical care: a scoping review

BACKGROUND

Target temperature management (TTM) is suggested to reduce brain damage in the presence of global or local ischemia. Prompt TTM application may help to improve outcomes, but it is often hindered by technical problems, mainly related to the portability of cooling devices and temperature monitoring systems. Tympanic temperature (T_Ty) measurement may represent a practical, non-invasive approach for core temperature monitoring in emergency settings, but its accuracy under different TTM protocols is poorly characterized. The present scoping review aimed to collect the available evidence about T_Ty monitoring in TTM to describe the technique diffusion in various TTM contexts and its accuracy in comparison with other body sites under different cooling protocols and clinical conditions.

METHODS

The scoping review was conducted following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews (PRISMA-ScR). PubMed, Scopus, and Web of Science electronic databases were systematically searched to identify studies conducted in the last 20 years, where T_Ty was measured in TTM context with specific focus on pre-hospital or in-hospital emergency settings.

RESULTS

The systematic search identified 35 studies, 12 performing T_Ty measurements during TTM in healthy subjects, 17 in patients with acute cardiovascular events, and 6 in patients with acute neurological diseases. The studies showed that T_Ty was able to track temperature changes induced by either local or whole-body cooling approaches in both pre-hospital and in-hospital settings. Direct comparisons to other core temperature measurements from other body sites were available in 22 studies, which showed a faster and larger change of T_Ty upon TTM compared to other core temperature measurements. Direct brain temperature measurements were available only in 3 studies and showed a good correlation between T_Ty and brain temperature, although T_Ty displayed a tendency to overestimate cooling effects compared to brain temperature.

CONCLUSIONS

T_Ty was capable to track temperature changes under a variety of TTM protocols and clinical conditions in both pre-hospital and in-hospital settings. Due to the heterogeneity and paucity of comparative temperature data, future studies are needed to fully elucidate the advantages of T_Ty in emergency settings and its capability to track brain temperature.

Use of infrared thermography to detect early alterations of peripheral perfusion: evaluation in a porcine model

This study aimed to evaluate the variations of infrared thermography according to rapid hemodynamic changes, by measuring the peripheral skin temperature in a porcine model. Eight healthy piglets were anesthetized and exposed to different levels of arterial pressure. Thermography was performed on the left forelimb to measure carpus and elbow skin temperature and their associated gradient with the core temperature. Changes in skin temperature in response to variations of blood pressure were observed. A negative correlation between arterial pressure and temperature gradients between peripheral and core temperature and a negative correlation between cardiac index and these temperature gradients were observed. Thermography may serve as a tool to detect early changes in peripheral perfusion.

Accuracy of the non-invasive Tcore™ temperature monitoring system to measure body core temperature in abdominal surgery

An accurate determination of body core temperature is crucial during surgery in order to avoid and treat hypothermia, which is associated with poor outcome. In a prospective observational study, we evaluated the suitability of the Tcore™ device (Drägerwerk AG & Co. KGaA, Lübeck, Germany)-a non-invasive thermometer-to accurately determine core body temperature. In patients undergoing surgery for ovarian cancer, core body temperature (CBT) was determined with the Tcore™ sensor attached to the forehead and compared with blood temperature (T_blood) as measured within the femoro-iliacal artery. Both temperatures were recorded every 10 s and the measurement error was calculated. 57,302 data pairs of CBT and T_blood were obtained in 22 patients. In a repeated-measurements version of the Bland and Altman test, a bias of - 0.02 °C and 95% limits of agreement of - 0.48 to 0.44 °C were calculated. In a population analysis, a median absolute error of 0 [- 0.1; + 0.1] °C, a bias of 0 [- 0.276; 0.271] % and an inaccuracy of 0.276 [0.274; 0.354] % was determined. Although the Tcore™ sensor was attached to the frontal skin, it provided an accurate measurement of core body temperature in the investigated intraoperative setting.

Intraoperative core temperature monitoring: accuracy and precision of zero-heat flux heated controlled servo sensor compared with esophageal temperature during major surgery; the ESOSPOT study

Monitoring of intraoperative core temperature is strongly recommended to reduce the risk of perioperative thermic imbalance and related complications. The zero-heat-flux sensor (3M Bair Hugger Temperature monitoring system, ZHF), measures core temperature in a non-invasive manner. This study was aimed at comparing accuracy and precision of the ZHF sensor compared to the esophageal thermometer. Patients scheduled for major elective abdominal or urologic surgery were considered eligible for enrollment. Core body temperature was measured using both an esophageal probe (T_ESO) and a ZHF sensor (T_ZHF) every 15 min from induction until the end of general anaesthesia. A Bland-Altman plot for repeated measures was performed. The proportion of measurements within ± 0.5 °C was estimated; from a clinical point of view, a proportion greater than 90% was considered sufficiently accurate. Lin's concordance correlation coefficient (CCC) for repeated measures were calculated. To evaluate association between the two methods, a generalized estimating equation (GEE) simple linear regression model, was elaborated. A GEE multiple regression model was also performed in order to adjust the estimate of the association between measurements from surgical and patient's features. Ninety-nine patients were enrolled. Bland-Altman plot bias was 0.005 °C with upper and lower limits of agreement for repeated measures of 0.50 °C and - 0.49 °C. The percentage of measurements within 0.5 °C of the reference value was 97.98% (95% confidence interval 92.89-99.75%), indicating a clinically sufficient agreement between the two methods. This was also confirmed by a CCC for repeated measures of 0.89 (95% CI 0.80 to 0.94). The GEE simple regression model (slope value of 0.77) was not significantly influenced by any patient or surgical variables. According to GEE multiple regression model results, the explored patient- and surgery-related variables did not influence the association between methods. ZHF sensor has shown a clinically acceptable accuracy and precision for body core temperature monitoring during elective major surgery. CLINICAL TRIALS: Clinical trial number: NCT03820232.

Comparison of temperature measurements in esophagus and urinary bladder in comatose patients after cardiac arrest undergoing mild therapeutic hypothermia

BACKGROUND

Mild therapeutic hypothermia (MTH) is a recommended method of treatment for comatose out-of-hospital cardiac arrest (OHCA) survivors. However, the proper site of temperature measurement in MTH is still not defined. The aim of this study was to compare temperature measurements in the esophagus and urinary bladder in comatose post-OHCA patients treated with MTH.

METHODS

This temperature comparison protocol was a part of a prospective, observational, multicenter cohort study. The study population included 36 unconscious patients after resuscitation for OHCA. The patient's core temperature was independently measured every hour during MTH in the urinary bladder and in the esophagus.

RESULTS

The mean temperature was lower in the esophagus (differences during induction phase: 1.04 ± 0.92°C, p < 0.0001; stabilization phase: 0.54 ± 0.39°C, p < 0.0001; rewarming phase: 0.40 ± 0.47°C, p < 0.0001). Nevertheless, a strong correlation between both sites was found (R2 = 0.83, p < 0.001). The decrease in temperature observed in the esophagus during the induction phase was faster when compared with the urinary bladder (1.09 ± 0.71°C/h vs. 0.83 ± 0.41°C/h; p = 0.002). As a consequence, time to reach temperature < 34.0°C was longer when temperature was measured in the urinary bladder (the difference between medians of the time 1.0 [0-1.5] h, p < 0.001).

CONCLUSIONS

Urinary bladder temperature measurements may lag behind temperature changes measured in the esophagus. Monitoring temperature simultaneously in the esophagus and in the urinary bladder is an accessible and reliable combination, although esophageal measurements seem to better reflect the dynamics of temperature changes, thus it seems to be more appropriate for MTH control. ClinicalTrials.gov Identifier: NCT02611934.

Validation of the Zero-Heat-Flux thermometer (SpotOn®) in major gynecological surgery to monitor intraoperative core temperature: a comparative study with esophageal core temperature

BACKGROUND

The Zero-Heat-Flux technology of the SpotOn® sensor to measure core temperature has been validated in vascular and cardiac surgery. Our aim was to assess its validity in gynecological surgery in terms of time of measurement, thermic status (hypo-, normo-, or hyperthermia) and the use of different warming devices.

METHODS

Prospective study in patients scheduled for major gynecological surgery using three warming systems (Snuggle Warm®, Lithotomy Underbody Blanket® and Warmtac Pad®). Intraoperative temperature was simultaneously monitored using the SpotOn® sensor and a Dräger® esophageal probe; measurements were taken after induction (T0), between 0 and 60 min (T1), between 60 and 120 minutes (T2) and after 120 minutes (T3). We calculated the level of correlation between pairs of measurements both overall and in subgroups with an acceptable difference of less than 0.5 °C. We built Bland-Altman plots, and calculated the Pearson correlation (PC) and intraclass correlation coefficient (ICC) to test our data.

RESULTS

We recruited 70 patients and included 66 for analysis, giving a total of 401 paired measurements. Overall, the PC and ICC for paired temperature readings were 0.82 and 0.90, respectively. The lowest levels of correlation were observed after intubation, when a convective blanket was placed under the patient, and in hypothermic patients. The highest correlations were observed at T2, and in normothermic patients.

CONCLUSIONS

We found a high overall correlation between the SpotOn® and the esophageal probe, with negligible differences and almost perfect agreement. The warming system used, time of measurement, and thermic status appear to influence the level of correlation, but these differences were not clinically significant.

Targeted temperature management in the ICU: Guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term "targeted temperature management" (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de réanimation de langue française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société française de médecine d'urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe francophone de réanimation et urgences pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association nationale de neuro-anesthésie réanimation française [ANARLF]), and the French Neurovascular Society (Société française neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts' opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Targeted temperature management in the ICU: guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term “targeted temperature management” (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d’Anesthésie Réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société Française de Médecine d’Urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe Francophone de Réanimation et Urgences Pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association Nationale de Neuro-Anesthésie Réanimation Française [ANARLF]), and the French Neurovascular Society (Société Française Neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts’ opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Re-visiting the tympanic membrane vicinity as core body temperature measurement site

Core body temperature (CBT) is an important and commonly used indicator of human health and endurance performance. A rise in baseline CBT can be attributed to an onset of flu, infection or even thermoregulatory failure when it becomes excessive. Sites which have been used for measurement of CBT include the pulmonary artery, the esophagus, the rectum and the tympanic membrane. Among them, the tympanic membrane is an attractive measurement site for CBT due to its unobtrusive nature and ease of measurement facilitated, especially when continuous CBT measurements are needed for monitoring such as during military, occupational and sporting settings. However, to-date, there are still polarizing views on the suitability of tympanic membrane as a CBT site. This paper will revisit a number of key unresolved issues in the literature and also presents, for the first time, a benchmark of the middle ear temperature against temperature measurements from other sites. Results from experiments carried out on human and primate subjects will be presented to draw a fresh set of insights against the backdrop of hypotheses and controversies.

Pre-hospital versus in-hospital initiation of cooling for survival and neuroprotection after out-of-hospital cardiac arrest

BACKGROUND

Targeted temperature management (also known under 'therapeutic hypothermia', 'induced hypothermia'", or 'cooling') has been shown to be beneficial for neurological outcome in patients who have had successful resuscitation from sudden cardiac arrest, but it remains unclear when this intervention should be initiated.

OBJECTIVES

To assess the effects of pre-hospital initiation of cooling on survival and neurological outcome in comparison to in-hospital initiation of cooling for adults with pre-hospital cardiac arrest.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, BIOSIS, and three trials registers from inception to 5 March 2015, and carried out reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We searched for randomized controlled trials (RCTs) in adults with out-of-hospital cardiac arrest comparing cooling in the pre-hospital setting to in-hospital cooling. Our primary outcomes were survival and neurological outcome; our secondary outcomes were adverse events, quality of life, and length of stay in the intensive care unit (ICU) and in the hospital.

DATA COLLECTION AND ANALYSIS

We used Cochrane's standard methodological procedures.

MAIN RESULTS

We included seven RCTs (2369 participants randomized) on the induction of pre-hospital cooling in comparison to in-hospital cooling. There was considerable methodological heterogeneity and risk of bias mainly due to deficits in the administration of cooling, therefore we refrained from pooling the results for survival and neurological outcome and we presented the results for each study separately. Adverse events were rare: based on four studies with 1713 adults pre-hospital induction of cooling may increase the risk of cardiac re-arrests. Risk of bias within the seven individual studies was generally moderate. Overall the quality of the evidence was very low. This was mainly driven by inconsistency and low precision.

AUTHORS' CONCLUSIONS

Currently, there is no convincing evidence to clearly delineate beneficial or harmful effects of pre-hospital induction of cooling in comparison to in-hospital induction of cooling. This conclusion is based on very low quality evidence.

A Survey of Accidental Hypothermia Knowledge among Navy Members in China and the Implications for Training

OBJECTIVES

Accidental hypothermia (AH) is a potentially life-threatening condition that can lead to significant morbidity and life-long effects. Navy personnel are always at a greater risk of AH due to frequent outdoor work, wilderness exposure, prolonged immobility and exhaustion. The purpose of the survey was to assess Chinese Navy members' awareness of AH and to make recommendations with regard to better measures for improving it.

METHODS

111 Navy members completed a written questionnaire that was subsequently analyzed.

RESULTS

30.6% of the respondents have experienced AH and 64.9% rated their knowledge of AH as "low" or "none". Over half of them identified the initial symptom of AH as obvious shivering (69.4%) and apathy (45.0%). As for the aggravate symptoms, 60.9% chose the wrong answer of more obvious shivering instead of the right one-absence of shivering (5.4%). In the case of the treatment of mild AH, more than half of the respondents chose the wrong answers.

CONCLUSIONS

This study suggests that the basic skills of recognition and treatment of AH are inadequate in the Chinese Navy. Further work is required to develop a systematical, comprehensive and corresponding education method that would promote correct actions during AH.

Zero-Heat-Flux Thermometry for Non-Invasive Measurement of Core Body Temperature in Pigs

Hypothermia is a severe, unpleasant side effect during general anesthesia. Thus, temperature surveillance is a prerequisite in general anesthesia settings during experimental surgeries. The gold standard to measure the core body temperature (T_core) is placement of a Swan-Ganz catheter in the pulmonary artery, which is a highly invasive procedure. Therefore, T_core is commonly examined in the urine bladder and rectum. However, these procedures are known for their inaccuracy and delayed record of temperatures. Zero-heat-flux (ZHF) thermometry is an alternative, non-invasive method quantifying T_core in human patients by applying a thermosensoric patch to the lateral forehead. Since the porcine cranial anatomy is different to the human’s, the optimal location of the patch remains unclear to date. The aim was to compare three different patch locations of ZHF thermometry in a porcine hypothermia model. Hypothermia (33.0°C T_core) was conducted in 11 anesthetized female pigs (26-30kg). T_core was measured continuously by an invasive Swan-Ganz catheter in the pulmonary artery (T_pulm). A ZHF thermometry device was mounted on three different defined locations. The smallest average difference between T_pulm and T_ZHF during stable temperatures was 0.21 ± 0.16°C at location A, where the patch was placed directly behind the eye. Also during rapidly changing temperatures location A showed the smallest bias with 0.48 ± 0.29°C. Location A provided the most reliable data for T_core. Therefore, the ZHF thermometry patch should be placed directly behind the left temporal corner of the eye to provide a non-invasive method for accurate measurement of T_core in pigs.

Therapeutic hypothermia following cardiac arrest

More than 10 years ago, the randomised studies of therapeutic hypothermia after cardiac arrest showed significant improvement of neurological outcome and survival. Since then, it has become clear that most of the possible adverse events of therapeutic hypothermia are mild and can easily be controlled by proper administration of intensive care. Although implementation of this effective therapy is quite successful, many questions of the exact treatment protocol still remain unanswered. Therapeutic hypothermia treatment therefore must be tailored to the specific patient's needs. Hence, the exact level of target temperature, duration of cooling, rewarming, timing of the therapy and concomitant medication to facilitate therapeutic hypothermia will be important in the future. Additionally, the use of a post-resuscitation treatment bundle (specialised cardiac-arrest centres including intensive post-resuscitation care, appropriate haemodynamic and respiratory management, therapeutic hypothermia and percutaneous coronary intervention) could further improve treatment of cardiac arrest.

Strategic target temperature management in myocardial infarction--a feasibility trial

OBJECTIVE

The purpose of this study was to demonstrate the feasibility of a combined cooling strategy started out of hospital as an adjunctive to percutaneous coronary intervention (PCI) in the treatment of ST-elevation acute coronary syndrome (STE-ACS).

DESIGN

Non-randomised, single-centre feasibility trial.

SETTING

Department of emergency medicine of a tertiary-care facility, Medical University of Vienna, Vienna, Austria. In cooperation with the Municipal ambulance service of the city of Vienna.

PATIENTS

Consecutive patients with STE-ACS presenting to the emergency medical service within 6 h after symptom onset.

INTERVENTIONS

Cooling was initiated with surface cooling pads in the out-of-hospital setting, followed by the administration of 1000-2000 mL of cold saline at hospital arrival and completed by endovascular cooling in the catheterisation laboratory.

MAIN OUTCOME MEASURES

Feasibility of lowering core temperature below 35.0°C prior to immediately performed revascularisation. Safety and tolerability of the cooling procedure.

RESULTS

In enrolled 19 patients (one woman, median age 51 years (IQR 45-59)), symptom onset to first medical contact (FMC) was 45 min (IQR 31-85). A core temperature below 35.0°C at reperfusion of the culprit lesion was achieved in 11 patients (78%) within 100 min (IQR 90-111) after FMC without any cooling-related serious adverse event. Temperature could be lowered from baseline 36.4°C (IQR 36.2-36.5°C) to 34.4°C (IQR 34.1-35.0°C) at the time of reperfusion.

CONCLUSIONS

With limitations an immediate out-of-hospital therapeutic hypothermia strategy was feasible and safe in patients with STE-ACS undergoing primary PCI.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov/ct2/show/NCT01864343; clinical trials unique identifier: NCT01864343.