Relationship between blood, nasopharyngeal and urinary bladder temperature during intravascular cooling for therapeutic hypothermia after cardiac arrest

Intraoperative zero-heat-flux thermometry overestimates nasopharyngeal temperature by 0.39 °C: an observational study in patients undergoing congenital heart surgery

During surgery for congenital heart disease (CHD) temperature management is crucial. Vesical (Tves) and nasopharyngeal (TNPH) temperature are usually measured. Whereas Tves slowly responds to temperature changes, TNPH carries the risk of bleeding. The zero-heat-flux (ZHF) temperature monitoring systems SpotOn™ (TSpotOn), and Tcore™ (Tcore) measure temperature non-invasively. We evaluated accuracy and precision of the non-invasive devices, and of Tves compared to TNPH for estimating temperature. In this prospective observational study in pediatric and adult patients accuracy and precision of TSpotOn, Tcore, and Tves were analyzed using the Bland-Altman method. Proportion of differences (PoD) and Lin´s concordance correlation coefficient (LCC) were calculated. Data of 47 patients resulted in sets of matched measurements: 1073 for TSpotOn vs. TNPH, 874 for Tcore vs. TNPH, and 1102 for Tves vs. TNPH. Accuracy was - 0.39 °C for TSpotOn, -0.09 °C for Tcore, and 0.07 °C for Tves. Precisison was between - 1.12 and 0.35 °C for TSpotOn, -0.88 to 0.71 °C for Tcore, and - 1.90 to 2.05 °C for Tves. PoD ≤ 0.5 °C were 71% for TSpotOn, 71% for Tcore, and 60% for Tves. LCC was 0.9455 for TSpotOn, 0.9510 for Tcore, and 0.9322 for Tves. Temperatures below 25.2 °C (TSpotOn) or 27.1 (Tcore) could not be recorded non-invasively, but only with Tves. Trial registration German Clinical Trials Register, DRKS00010720.

Temperature management in the intensive care unit: a practical survey from China

Introduction: Temperature management is an important aspect of the treatment of critically ill patients, but there are differences in the measurement and management of temperature in different Intensive Care Units (ICUs). The objective of this study was to understand the current situation of temperature measurement and management in ICUs in China, and to provide a basis for standardized temperature management in ICUs.Methods: A 20-question survey was used to gather information on temperature management strategies from ICUs across China. Data such as method and frequency of temperature measurement, management goals, cooling measures, and temperature management recommendations were collected.Results: A total of 425 questionnaires from unique ICUs were included in the study, with responses collected from all provinces and autonomous regions in China. Mercury thermometers were the most widely used measurement tool (82.39%) and the axilla was the most common measurement site (96.47%). There was considerable variability in the frequency of temperature measurement, the temperature at which intervention should begin, intervention duration, and temperature management goals. While there was no clearly preferred drug-based cooling method, the most widely used equipment-based cooling method was the ice blanket machine (93.18%). The most frequent recommendations for promoting temperature management were continuous monitoring and targeted management.Conclusion: Our investigation revealed a high level of variability in the methods of temperature measurement and management among ICUs in China. Since fever is a common clinical symptom in critically ill patients and can lead to prolonged ICU stays, we propose that standardized guidelines are urgently needed for the management of body temperature (BT) in these patients.

Bladder Temperature During Neonatal Targeted Temperature Management: A Case Report

BACKGROUND

Neonatal encephalopathy is a clinical condition of altered neurological function in the first days of life. Targeted temperature management (TTM) is a validated approach to mitigate neurologic sequelae. Current literature suggests using rectal or esophageal site to assess temperature during TTM, but few studies focused on the best and the less invasive site to evaluate the temperature. This case report describes the performance of the bladder temperature monitoring during TTM.

CLINICAL FINDINGS

A female newborn was born at 39 weeks' gestational age plus 4 days. At delivery, the newborn was in cardiorespiratory arrest.

PRIMARY DIAGNOSIS

After performing cardiopulmonary resuscitation and neurological examination, a hypoxic-ischemic encephalopathy was diagnosed.

INTERVENTIONS

After about 2 hours from birth, the newborn underwent TTM.

OUTCOMES

A total of 4642 measurements of rectal temperature and 4520 measurements of bladder temperature were collected. Agreement between the 2 sites was statistically significant with a mean difference of 0.064°C ± 0.219 (95% confidence interval, -0.364 to 0.494); F = 47.044; and P value of less than .001. Furthermore, difference between rectal and bladder sites was not influenced by patient's urine output ( F = 0.092, P = .762).

PRACTICE RECOMMENDATIONS

Bladder temperature seems to have a good reliability and not to be inferior to the other assessment site currently used. Using bladder catheter with temperature sensor could reduce the number of devices, ensure safer stabilization, and decrease treatment downtime.

Impact of rewarming rate on interleukin-6 levels in patients with shockable cardiac arrest receiving targeted temperature management at 33 °C: the ISOCRATE pilot randomized controlled trial

Purpose

While targeted temperature management (TTM) has been recommended in patients with shockable cardiac arrest (CA) and suggested in patients with non-shockable rhythms, few data exist regarding the impact of the rewarming rate on systemic inflammation. We compared serum levels of the proinflammatory cytokine interleukin-6 (IL6) measured with two rewarming rates after TTM at 33 °C in patients with shockable out-of-hospital cardiac arrest (OHCA).

Methods

ISOCRATE was a single-center randomized controlled trial comparing rewarming at 0.50 °C/h versus 0.25 °C/h in patients coma after shockable OHCA in 2016–2020. The primary outcome was serum IL6 level 24–48 h after reaching 33 °C. Secondary outcomes included the day-90 Cerebral Performance Category (CPC) and the 48-h serum neurofilament light-chain (NF-L) level.

Results

We randomized 50 patients. The median IL6 area-under-the-curve was similar between the two groups (12,389 [7256–37,200] vs. 8859 [6825–18,088] pg/mL h; P = 0.55). No significant difference was noted in proportions of patients with favorable day-90 CPC scores (13/25 patients at 0.25 °C/h (52.0%; 95% CI 31.3–72.2%) and 13/25 patients at 0.50 °C/h (52.0%; 95% CI 31.3–72.2%; P = 0.99)). Median NF-L levels were not significantly different between the 0.25 °C/h and 0.50 °C/h groups (76.0 pg mL, [25.5–3074.0] vs. 192 pg mL, [33.6–4199.0]; P = 0.43; respectively).

Conclusion

In our RCT, rewarming from 33 °C at 0.25 °C/h, compared to 0.50 °C/h, did not decrease the serum IL6 level after shockable CA. Further RCTs are needed to better define the optimal TTM strategy for patients with CA.

Trial registration ClinicalTrials.gov, NCT02555254. Registered September 14, 2015.

Take-Home Message: Rewarming at a rate of 0.25 °C/h, compared to 0.50 °C, did not result in lower serum IL6 levels after achievement of hypothermia at 33 °C in patients who remained comatose after shockable cardiac arrest. No associations were found between the slower rewarming rate and day-90 functional outcomes or mortality.

140-character Tweet: Rewarming at 0.25 °C versus 0.50 °C did not decrease serum IL6 levels after hypothermia at 33 °C in patients comatose after shockable cardiac arrest.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03842-9.

Post-cardiac arrest care and targeted temperature management: A consensus of scientific statement from the Taiwan Society of Emergency & Critical Care Medicine, Taiwan Society of Critical Care Medicine and Taiwan Society of Emergency Medicine

BACKGROUND

Post-cardiac arrest care is critically important in bringing cardiac arrest patients to functional recovery after the detrimental event. More high quality studies are published and evidence is accumulated for the post-cardiac arrest care in the recent years. It is still a challenge for the clinicians to integrate these scientific data into the real clinical practice for such a complicated intensive care involving many different disciplines.

METHODS

With the cooperation of the experienced experts from all disciplines relevant to post-cardiac arrest care, the consensus of the scientific statement was generated and supported by three major scientific groups for emergency and critical care in post-cardiac arrest care.

RESULTS

High quality post-cardiac arrest care, including targeted temperature management, early evaluation of possible acute coronary event and intensive care for hemodynamic and respiratory care are inevitably needed to get full recovery for cardiac arrest. Management of these critical issues were reviewed and proposed in the consensus CONCLUSION: The goal of the statement is to provide help for the clinical physician to achieve better quality and evidence-based care in post-cardiac arrest period.

Comparison of a Continuous Noninvasive Temperature to Monitor Core Temperature Measures During Targeted Temperature Management

Background

Temperature modulating devices (TMD) currently utilize core temperature measurements during targeted temperature management (TTM) that are currently limited to esophageal (Et), bladder (Bt), or rectal (Rt) temperatures. We assessed the ability of a continuous noninvasive temperature monitor to accurately approximate core temperature during TTM.

Methods

All patients undergoing TTM using a gel pad surface TMD and an existing core temperature monitoring device were eligible for this study. Core and continuous noninvasive temperature monitoring values were simultaneously recorded for up to 72 h of TTM. The two sets of temperature data were downloaded from a clinical data acquisition storage system at 1-min intervals. The Bland–Altman method assessed agreement between the core and continuous noninvasive temperature monitor values, by measuring the mean difference (± 2 SD) between these values.

Results

There were 20 subjects that underwent study between January 2018 and March 2018 (55% women, age: 57 ± 14 years old, BMI: 28.9 + 9.8 kg/m², 100% mechanically ventilated). The comparison patient temperature source was predominantly esophageal (n = 10) followed by bladder (n = 5) or rectal (n = 5). There were a total of 999 h of paired patient temperature data from esophageal (50%), bladder (25%), and rectal (25%) temperatures. Bland–Altman analysis demonstrated good agreement with the superficial temperature monitor and core temperature measures in all patients overall, with a difference mean of 0.06 ± 0.39 C (P = 0.99) and no proportional bias noted (β =0.002, P = 0.917).

Conclusions

Continuous noninvasive temperature monitoring is a suitable alternative method for assessing core temperature during TTM. Future studies should focus on developing connectivity with a continuous noninvasive temperature monitor to approximate core temperature during TTM.

Intravascular Cooling Device Versus Esophageal Heat Exchanger for Mild Therapeutic Hypothermia in an Experimental Setting

BACKGROUND

Targeted temperature management is a standard therapy for unconscious survivors of cardiac arrest. To date, multiple cooling methods are available including invasive intravascular cooling devices (IVDs), which are widely used in the clinical setting. Recently, esophageal heat exchangers (EHEs) have been developed providing cooling via the esophagus that is located close to the aorta and inferior vena cava. The objective was to compare mean cooling rates, as well as differences, to target temperature during maintenance and the rewarming period of IVD and EHE.

METHODS

The study was conducted in 16 female domestic pigs. After randomization to either IVD or EHE (n = 8/group), core body temperature was reduced to 33°C. After 24 hours of maintenance (33°C), animals were rewarmed using a target rate of 0.25°C/h for 10 hours. All cooling phases were steered by a closed-loop feedback system between the internal jugular vein and the chiller. After euthanasia, laryngeal and esophageal tissue was harvested for histopathological examination.

RESULTS

Mean cooling rates (4.0°C/h ± 0.4°C/h for IVD and 2.4°C/h ± 0.3°C/h for EHE; P < .0008) and time to target temperature (85.1 ± 9.2 minutes for IVD and 142.0 ± 21.2 minutes for EHE; P = .0008) were different. Mean difference to target temperature during maintenance (0.07°C ± 0.05°C for IVD and 0.08°C ± 0.10°C for EHE; P = .496) and mean rewarming rates (0.2°C/h ± 0.1°C/h for IVD and 0.3°C/h ± 0.2°C/h for EHE; P = .226) were similar. Relevant laryngeal or esophageal tissue damage could not be detected. There were no significant differences in undesired side effects (eg, bradycardia or tachycardia, hypokalemia or hyperkalemia, hypoglycemia or hyperglycemia, hypotension, overcooling, or shivering).

CONCLUSIONS

After insertion, target temperatures could be reached faster by IVD compared to EHE. Cooling performance of IVD and EHE did not significantly differ in maintaining target temperature during a targeted temperature management process and in active rewarming protocols according to intensive care unit guidelines in this experimental setting.

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.

Rectal and Bladder Temperatures vs Forehead Core Temperatures Measured With SpotOn Monitoring System

BACKGROUND

Methods and frequency of temperature monitoring in intensive care unit patients vary widely. The recently available SpotOn system uses zero-heat-flux technology and offers a noninvasive method for continuous monitoring of core temperature of critical care patients at risk for alterations in body temperature.

OBJECTIVE

To evaluate agreement between and precision of a zero-heat-flux thermometry system (SpotOn) and continuous rectal and urinary bladder thermometry during fever and defervescence in adult patients in intensive care units.

METHODS

Prospective comparison of SpotOn vs rectal and urinary bladder thermometry in eligible patients enrolled in a randomized clinical trial on the effect of acetaminophen on core body temperature and hemodynamic status.

RESULTS

A total of 748 paired temperature measurements from 38 patients who had both SpotOn monitoring and either continuous rectal or continuous bladder thermometry were analyzed. Temperatures during the study were from 36.6°C to 39.9°C. The mean difference for SpotOn compared with bladder thermometry was -0.07°C (SD, 0.24°C; 95% limits of agreement, ± 0.47°C [-0.54°C, 0.40°C]). The mean difference for SpotOn compared with rectal thermometry was -0.24°C (SD, 0.29°C; 95% limits of agreement, ± 0.57°C [-0.81°C, 0.33°C]). Most differences in temperature between methods were within ± 0.5°C in both groups (96% bladder and 85% rectal).

CONCLUSIONS

The SpotOn thermometry system has excellent agreement and good precision and is a potential alternative for noninvasive continuous monitoring of core temperature in critical care patients, especially when alternative methods are contraindicated or not available.

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.

Body temperature measurements in pigs during general anaesthesia

The aim was to compare rectal, pharyngeal and oesophageal temperature measurements in anaesthetized pigs. Data were compared using the Bland-Altman method, and correlation coefficients and error measures were calculated. Sixty-six sets of data were collected from 16 pigs weighing 16.2 ± 4.2 kg. The bias (and 95% limit of agreement) for rectal and pharyngeal compared with oesophageal temperature were 0.69 (-1.18 to 2.57) ℃ and 0.22 (-0.84 to 1.28) ℃, respectively. The correlation coefficients for rectal and pharyngeal compared with oesophageal temperature were 0.47 and 0.87, respectively. The absolute error for rectal and pharyngeal compared with oesophageal temperature was 0.7 ± 0.9℃ and 0.2 ± 0.5℃, respectively. Pharyngeal temperature measurement may be more suitable than rectal temperature measurement for estimation of oesophageal temperature during general anaesthesia of pigs.