Hypothermia Group Research Articles

Speed of cooling after cardiac arrest in relation to the intervention effect: a sub-study from the TTM2-trial

BackgroundTargeted temperature management (TTM) is recommended following cardiac arrest; however, time to target temperature varies in clinical practice. We hypothesised the effects of a target temperature of 33 °C when compared to normothermia would differ based on average time to hypothermia and those patients achieving hypothermia fastest would have more favorable outcomes.MethodsIn this post-hoc analysis of the TTM-2 trial, patients after out of hospital cardiac arrest were randomized to targeted hypothermia (33 °C), followed by controlled re-warming, or normothermia with early treatment of fever (body temperature, ≥ 37.8 °C). The average temperature at 4 h (240 min) after return of spontaneous circulation (ROSC) was calculated for participating sites. Primary outcome was death from any cause at 6 months. Secondary outcome was poor functional outcome at 6 months (score of 4–6 on modified Rankin scale).ResultsA total of 1592 participants were evaluated for the primary outcome. We found no evidence of heterogeneity of intervention effect based on the average time to target temperature on mortality (p = 0.17). Of patients allocated to hypothermia at the fastest sites, 71 of 145 (49%) had died compared to 68 of 148 (46%) of the normothermia group (relative risk with hypothermia, 1.07; 95% confidence interval 0.84–1.36). Poor functional outcome was reported in 74/144 (51%) patients in the hypothermia group, and 75/147 (51%) patients in the normothermia group (relative risk with hypothermia 1.01 (95% CI 0.80–1.26).ConclusionsUsing a hospital’s average time to hypothermia did not significantly alter the effect of TTM of 33 °C compared to normothermia and early treatment of fever.

Expression of Superoxide Dismutase-1 (SOD-1) and changes of corneal endothelial morphology after phacoemulsification with hypothermic perfusion

Background: Hypothermic perfusion can be used as adjunctive therapy to reduce corneal endothelial cell damage during phacoemulsification procedures. This study aims to evaluate the effect of hypothermic perfusion on the expression of Superoxide Dismutase-1 (SOD1) and morphological changes in the corneal endothelium after ultrasound energy of phacoemulsification exposure. Methods: Sixteen New Zealand white rabbits (n=16 eyes) were randomly divided into two groups and exposed to ultrasound energy of phacoemulsification. The control group was administered room temperature (RT) (24°C) Balanced Salt Solution (BSS) intraocular perfusion, and the treatment group was administered hypothermic (4°C) BSS intraocular perfusion. Coefficient of Variation (CV) and hexagonality were measured before and one day after surgery with specular microscopy. The expression of SOD1 was examined by immunohistochemistry staining. Data were analyzed using SPSS version 26 for Windows. Results: The result showed that the SOD1 expression was significantly lower in the hypothermic perfusion group compared with the control group (p=0.024, p<0.05). There were no significant differences between the two groups in CV changes (p=0.494, p>0.05) and hexagonality changes (p=0.916, p>0.05). There was no correlation between the expression of SOD1 and change in CV (p=0.188, p>0.05) or the expression of SOD1 and change in hexagonality (p=0.763, p>0.05). Conclusion: Hypothermic perfusion suppresses all metabolic processes, including the expression of SOD1 and ROS production. The coefficient of variation and hexagonality as a representative of corneal endothelial morphology changes also decrease with hypothermic perfusion after ultrasound exposure but are not statistically significant. There is no correlation between the expression of SOD1 and changes in CV and hexagonality.

Abstract 286: Hypothermic Out-of-hospital Cardiac Arrest: Favorable Outcomes, But With Limited Defibrillation Or Adrenaline Administration Effectiveness In The Prehospital Setting

Introduction: Hypothermic out-of-hospital cardiac arrest (OHCA) is assumed to be associated with favorable neurological outcomes compared with OHCA from other etiologies. However, supporting evidence is limited. In addition, inconsistencies for number of defibrillation and adrenaline administration attempts in prehospital management guidelines can be identified. Hypothesis: We evaluated whether hypothermic OHCA is associated with favorable outcomes compared with OHCA from other etiologies. Further, the effectiveness of defibrillation or adrenaline administration was evaluated. Methods: Using data from a nationwide, population-based retrospective study conducted in Japan from 2013 to 2016, we compared two OHCA patient groups: patients with hypothermic etiology and those with non-hypothermic etiology. The primary outcome measure was one-month favorable neurological outcomes, defined as Cerebral Performance Category score ≤ 2. Multivariable logistic regression was used to calculate odds ratios (ORs) and their confidence intervals (CIs) to evaluate the impact of hypothermic OHCA. We further looked for an association between prehospital management and neurological outcomes among patients with hypothermic etiology. Results: We divided the cohort of 477,606 OHCA patients into the hypothermic group (n=842) and the non-hypothermic group (n=476,763). The hypothermic group had significantly higher odds of favorable neurological outcomes (64/842 (7.6%) vs. 13,052/476,763 (1.4 %), adjusted OR 3.12, 95%, CI 1.96-4.96) compared with the non-hypothermic group. In the hypothermic group, prehospital defibrillation (OR 1.52, 95%, CI 0.86-2.68) and adrenaline administration (OR 1.32, 95%, CI 0.67-2.62) did not contribute to favorable neurological outcomes overall. However, when the data was stratified by age and number of shocks, three or less defibrillation attempts in patients under 65 years old (OR 3.37, 95%, CI 1.31-8.67) was associated with favorable neurological outcomes. Conclusion: We found that hypothermic OHCA was associated with a higher chance of a favorable neurological outcome. Even prehospital defibrillation seems to have limited efficacy for hypothermic OHCA.

Outcomes of mild-to-moderate postresuscitation shock after non-shockable cardiac arrest and association with temperature management: a post hoc analysis of HYPERION trial data

BackgroundOutcomes of postresuscitation shock after cardiac arrest can be affected by targeted temperature management (TTM). A post hoc analysis of the “TTM1 trial” suggested higher mortality with hypothermia at 33 °C. We performed a post hoc analysis of HYPERION trial data to assess potential associations linking postresuscitation shock after non-shockable cardiac arrest to hypothermia at 33 °C on favourable functional outcome.MethodsWe divided the patients into groups with vs. without postresuscitation (defined as the need for vasoactive drugs) shock then assessed the proportion of patients with a favourable functional outcome (day-90 Cerebral Performance Category [CPC] 1 or 2) after hypothermia (33 °C) vs. controlled normothermia (37 °C) in each group. Patients with norepinephrine or epinephrine > 1 µg/kg/min were not included.ResultsOf the 581 patients included in 25 ICUs in France and who did not withdraw consent, 339 had a postresuscitation shock and 242 did not. In the postresuscitation-shock group, 159 received hypothermia, including 14 with a day-90 CPC of 1–2, and 180 normothermia, including 10 with a day-90 CPC of 1–2 (8.81% vs. 5.56%, respectively; P = 0.24). After adjustment, the proportion of patients with CPC 1–2 also did not differ significantly between the hypothermia and normothermia groups (adjusted hazards ratio, 1.99; 95% confidence interval, 0.72–5.50; P = 0.18). Day-90 mortality was comparable in these two groups (83% vs. 86%, respectively; P = 0.43).ConclusionsAfter non-shockable cardiac arrest, mild-to-moderate postresuscitation shock at intensive-care-unit admission did not seem associated with day-90 functional outcome or survival. Therapeutic hypothermia at 33 °C was not associated with worse outcomes compared to controlled normothermia in patients with postresuscitation shock.Trial registration ClinicalTrials.gov, NCT01994772

A novel scoring system (YASHMA) predicting brain injury in asphyxiated newborns.

Hypoxic-ischemic encephalopathy is a complication of adverse intrapartum events and birth asphyxia resulting in brain injury and mortality in late preterm and term newborns. In this study, we aimed to predict brain damage on magnetic resonance imaging (MRI) with a new scoring system. Yieldly And Scorable Holistic Measuring of Asphyxia (YASHMA) is generated for detection of brain injury in asphyxiated newborns. Total scores were calculated according to scores of birth weight, gestation weeks, APGAR scores at first and fifth minutes, aEEG patterns and epileptic status of patients. The major outcome of the scoring system was to determine correlation between poor scores and neonatal brain injury detected on MRI. In hypothermia group with brain injury, low gestational weeks and lowest APGAR scores, abnormal aEEG findings were statistically different from others. YASHMA scores were statistically significant with high sensitivity, specificity, AUC and 95% confidence interval values. YASHMA scoring system is feasible and can be suggestive for detecting brain injury in low-income countries.

Robotic Level IV Inferior Vena Cava Thrombectomy Using an Intrapericardial Control Technique: Is It Safe Without Cardiopulmonary Bypass?

We introduce an intrapericardial control technique using a robotic approach in the surgical treatment of renal tumor with level IV inferior vena cava thrombus to decrease the severe complications associated with cardiopulmonary bypass and deep hypothermic circulatory arrest. Eight patients with level IV inferior vena cava thrombi not extending into the atrium underwent transabdominal-transdiaphragmatic robot-assisted inferior vena cava thrombectomy obviating cardiopulmonary bypass/deep hypothermic circulatory arrest (cardiopulmonary bypass-free group) by an expert team comprising urological, hepatobiliary, and cardiovascular surgeons. The central diaphragm tendon and pericardium were transabdominally dissected until the intrapericardial inferior vena cava were exposed and looped proximal to the cranial end of the thrombi under intraoperative ultrasound guidance. As controls, 14 patients who underwent robot-assisted inferior vena cava thrombectomy with cardiopulmonary bypass (cardiopulmonary bypass group) and 25 patients who underwent open thrombectomy with cardiopulmonary bypass/deep hypothermic circulatory arrest (cardiopulmonary bypass/deep hypothermic circulatory arrest group) were included. Clinicopathological, operative, and survival outcomes were retrospectively analyzed. Eight robot-assisted inferior vena cava thrombectomies were successfully performed without cardiopulmonary bypass, with 1 open conversion. The median operation time and first porta hepatis occlusion time were shorter, and estimated blood loss was lower in the cardiopulmonary bypass-free group as compared to the cardiopulmonary bypass group (540 vs 586.5 minutes, 16.5 vs 38.5. minutes, and 2,050 vs 3,500 mL, respectively). Severe complications (level IV-V) were also lower in the cardiopulmonary bypass-free group than in cardiopulmonary bypass and cardiopulmonary bypass/deep hypothermic circulatory arrest groups (25% vs 50% vs 40%). Oncologic outcomes were comparable among the 3 groups in short-term follow-up. Pure transabdominal-transdiaphragmatic robot-assisted inferior vena cava thrombectomy without cardiopulmonary bypass/deep hypothermic circulatory arrest represents as an alternative minimally invasive approach for selected level IV inferior vena cava thrombi.

Hypothermia yields favourable cardiac energetics in experimental ischemia/reperfusion – insights from non-invasive pressure-volume loops by CMR

Abstract Background/Introduction In experimental studies, mild hypothermia (<35°C) has reduced infarct size [1], potentially through reduced reperfusion injury [2], but human trials have been ambiguous [3]. Furthermore, a pressure-volume (PV) loop framework is the gold standard for assessing cardiac performance, but the invasive approach limits its clinical use. Therefore, we used a porcine model of ischemia/reperfusion with cardiovascular magnetic resonance (CMR) imaging throughout one week to acquire non-invasive PV loops. Purpose To quantify the cardioprotective effects of hypothermia at reperfusion by serial CMR imaging in a perspective of cardiac energy and mechanics. Methods Normothermia and Hypothermia groups (n=7+7 pigs) were imaged with CMR at baseline and subjected to 40 minutes of normothermic ischemia by catheter intervention. Thereafter, the Hypothermia group was rapidly cooled (<35°C) for 5 minutes before reperfusion. Additional imaging at two hours, 24 hours, and seven days were used to assess ventricular volumes and ischemic injuries. Infarct size was determined by high-resolution ex-vivo T1-weighted images. Results Figure 1 shows that stroke volume (SV: p=0.029; Friedmans test) and ejection fraction (EF: p=0.068) were notably reduced post-reperfusion in the Normothermia group. In contrast, the decreases were ameliorated in the Hypothermia group (SV: p=0.77; EF: p=0.13). Mean arterial pressure (MAP) was stable in the Normothermia group (p=0.77) but dropped two hours post-reperfusion in hypothermic animals (p=0.007). Over one week, both groups experienced the same decrease and partial recovery pattern for stroke work, external power, and ventricular-arterial coupling. Still, the adverse effects from ischemia were generally attenuated in the Hypothermia group. Although not significant, ischemia/reperfusion caused smaller infarcts in the Hypothermia group (10±8% vs 15±8%; p=0.32). The change in PV loop variables from baseline to 24 hours was compared with infarct size for each group. Though statistical power was limited, the general trend in analyses of covariance indicated that hypothermia has cardioprotective properties incremental to reducing infarct sizes (Figure 2), such as higher external power (p=0.061) and lower arterial elastance (p=0.015). Conclusion Using non-invasive PV loops by CMR, we observed that mild hypothermia before reperfusion results in favourable cardiac energetics that alleviates the heart's work after an ischemia/reperfusion injury during the first week. This study suggests that hypothermia has cardioprotective properties, incremental to reducing infarct size. The primary cardioprotective mechanism was likely an afterload reduction unloading the injured left ventricle. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Swedish Heart-Lung FoundationThe Medical Faculty of Lund University (ALF)

Application of Modest Hypothermia in Patients with Acute Traumatic Cervical Spine Injury: A Pilot Study.

This prospective randomized controlled study aimed to examine the role of modest systemic hypothermia in individuals with acute cervical spinal cord injury (SCI) regarding neurological improvement. Studies have shown that the application of hypothermia is safe and that it improves neurological outcomes in patients with traumatic spine injury. Hypothermia helps in decreasing a secondary damage to the cord. Twenty cases of acute post-traumatic cervical SCI with AISA were selected and randomly divided into two treatment groups: Group A-Hypothermia with surgical decompression and stabilization; and Group B-Normothermia with surgical decompression and stabilization. American Spinal Injury Association (ASIA) motor and sensory scores were evaluated at presentation; post-surgery; and at a 2-week, 6-week, and 12-week follow-up. At the final follow-up, the change in ASIA motor scores of Group A was 46 (11.5-70.5) and Group B 13 (4.5-58.0), whereas ASIA sensory scores were 118 (24.75-186.5) and 29 (15.25-124.0) in Group A and Group B, respectively. ASIA scores between the two groups were statistically significantly different at a 2-week follow-up (ASIA motor p=0.04, ASIA sensory p=0.006), showing early improvement in the hypothermia group. There was no significant difference between the two groups on further follow-up. Hypothermia can be applied safely to subjects with acute SCI. Our study showed that hypothermia was beneficial in the early improvement of functional outcomes in acute cervical SCI.

Hypothermia and Prolonged Time From Procedure End to Extubation After Endovascular Thoracic Aortic Surgery

Perioperative hypothermia (core temperature <36°C) occurs in 50%-to-80% of patients recovering from thoracic aortic surgery, though its effects have not been described fully in this context. The authors, therefore, sought to characterize the incidence of perioperative hypothermia and its association with time from procedure end to extubation in endovascular aortic surgical patients. A retrospective cohort study. At a single academic tertiary center. Patients recovering from thoracic aortic surgery with lumbar drains. None. A total of 196 patients were included in this study, 55 of whom were hypothermic with temperatures <35.0°C at the end of surgery. Though the unadjusted time to extubation was not statistically different in the hypothermic group (median 8 minutes, IQR 5-13.5 minutes) compared to the normothermic group (median 7 minutes, IQR 4-12 minutes; p=0.062), multivariate predictors of increased time from procedure end to extubation included hypothermia (p=0.011), age (p=0.009), diabetes (p=0.015), history of carotid disease (p=0.040), and crystalloid volume (p=0.019). Hypothermia in patients recovering from endovascular aortic surgery was associated with prolonged time from procedure end to extubation. Because of the retrospective observational nature of the authors' analysis, it was not possible to determine the extent to which prolonged mechanical ventilation was influenced by low temperature.

Mild hypothermia during cardiopulmonary bypass assisted CABG is associated with improved short- and long-term survival, a 18-year cohort study.

Data substantiating the optimal patient body temperature during cooling procedures in cardiac operations are currently unavailable. To explore the optimal temperature strategy, we examined the association between temperature management and survival among patients during cardiopulmonary bypass assisted coronary artery bypass grafting (CABG) procedures on 30-days and 5-year postoperative survival. Adult patients (n = 5,672, 23.6% female and mean (SD) age of 66 (10) years) operated between 1997 and 2015 were included, with continuous measured intraoperative nasopharyngeal temperatures. The association between mortality and patient characteristics, laboratory parameters, the lowest intraoperative plateau temperature and intraoperative cooling/rewarming rates were examined by multivariate Cox regression analysis. Machine learning-based cluster analysis was used to identify patient subgroups based on pre-cooling parameters and explore whether specific subgroups benefitted from a particular temperature management. Mild hypothermia (32–35°C) was independently associated with improved 30-days and 5-year survival compared to patients in other temperature categories regardless of operation year. 30 days and 5-year survival were 98% and 88% in the mild hypothermia group, whereas it amounted 93% and 80% in the severe hypothermia (<30°C). Normothermia (35–37°C) showed the lowest survival after 30 days and 5 years amounting 93% and 72%, respectively. Cluster analysis identified 8 distinct patient subgroups principally defined by gender, age, kidney function and weight. The full cohort and all patient subgroups displayed the highest survival at a temperature of 32°C. Given these associations, further prospective randomized controlled trials are needed to ascertain optimal patient temperatures during CPB.

Early predictors of brain injury in patients with acute carbon monoxide poisoning and the neuroprotection of mild hypothermia

IntroductionCarbon monoxide (CO) poisoning can cause serious neurological sequelae. However, there is neither effective treatment strategy nor reliable indicators to determine the prognosis of patients with CO poisoning. The present study aimed to observe the changes of neurological function score, disease severity score, cerebral oxygen utilization (O2UCc), bispectral (BIS) index and neuron-specific enolase (NSE) concentration, and to elucidate the clinical significance of these potential indicators and the neuroprotective effect of mild hypothermia on brain injury in patients with severe acute CO poisoning. Materials and methodsA total of 277 patients with acute severe CO poisoning from 2013 to 2018 were enrolled in our hospital. Patients were divided into three groups according to their body temperature on the day of admission and their willingness to treat: a fever group (n = 78), a normal temperature group (NT group, n = 113), and a mild hypothermia group (MH group, n = 86). All patients were given hyperbaric oxygen therapy, while those in the MH group received additional mild hypothermia treatment. The severity of the disease, the neurobehavioral status, the incidence of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP), and other indicators including BIS, O2UCc, NSE were further evaluated in all patients at given time-points. ResultsMild hypothermia therapy improved the prognosis of patients with CO poisoning, significantly decreased the value of O2UCc and NSE, and up-regulated BIS. The incidence of DEACMP at 6 months was 27% in the fever group, 23% in the NT group, and 8% in the MH group. The values of Glasgow-Pittsburgh coma scale (G-P score), BIS index and NSE were closely related to the occurrence of DEACMP, the cutoff values were 12.41, 52.17 and 35.20 ng/mL, and the sensitivity and specificity were 79.3%, 77.6%, 79.3% and 67.6%, 89.5%, 88.6% in the receiver operating characteristic curve (ROC), respectively. ConclusionsEarly mild hypothermia treatment could significantly reduce the severity of brain injury after CO poisoning, and might be further popularized in clinic. G-P scores, NSE and BIS index can be regarded as the prediction indicators in the occurrence and development of DEACMP. Clinical trial registrationThe study protocol was granted from Qingdao University Research Ethics Committee (Clinical trial registry and ethical approval number: QD81571283).

The prognostic impact of therapeutic hypothermia after a sudden cardiac arrest in the course of myocardial infarction.

Mild therapeutic hypothermia (MTH) is one of the treatment methods recommended in post-sudden cardiac arrest (SCA) patients who remain unconscious after cardiopulmonary resuscitation. The present study aimed at assessing the prognostic impact of intravascular MTH on invasively treated patients with an acute myocardial infarction complicated by SCA. The presented data were collected via a single-center retrospective analysis of the hospitalization and follow-up of 54 patients with post-myocardial infarction complicated by SCA. The patients were treated in the years 2014-2020 and the average follow-up period was 1141 ± 163 days. The population was divided into two groups: 28 patients treated with MTH (a therapeutic hypothermia [TH] group) and 26 patients treated without MTH (a non-TH group). The results indicate a trend toward improved in-hospital prognosis in the TH group, but the differences did not reach statistical significance: TH 25.0% vs. non-TH 34.5%, p = 0.554. An additional analysis of younger patients (under 60 years of age) revealed no significant differences between the TH and non-TH subgroups concerning in-hospital survival (in-hospital mortality rate: TH 6.7% vs. non-TH 30.0%, p = 0.267). Still, TH patients aged < 60 achieved a significantly better rate of follow-up survival (p = 0.041). The older (≥ 60) patient group showed no in-hospital mortality rate differences (TH 46.2% vs. non-TH 37.5%, p = 0.638). However, in-hospital bleeding frequency was significantly higher in patients aged ≥ 60 from the hypothermia group (TH 50.0% vs. non-TH 6.7%, p = 0.011). Intravascular MTH may improve the follow-up prognosis in patients aged < 60 with SCA in the early phase of myocardial infarction.

Therapeutic hypothermia in patients with poor-grade aneurysmal subarachnoid hemorrhage

ObjectiveTherapeutic hypothermia improves the prognosis of patients with poor-grade subarachnoid hemorrhage (SAH). We investigated the clinical and radiological effects of therapeutic hypothermia in patients with poor-grade SAH. MethodsClinical and radiological data were compared between patients who underwent mild hypothermic treatment and those who underwent treatment without hypothermia. ResultsAmong 670 patients with SAH, 72 had poor-grade SAH. After early clipping or coiling of the aneurysm, 25 patients underwent mild hypothermia and the remaining 47 patients underwent no hypothermia. The medical complication occurrence rates were similar between the hypothermia treatment and control groups. Significantly, cerebral edema was reduced in patients in the hypothermia group (44 %) compared with those in the no-hypothermia group (9 %) (p = 0.025). The poor clinical outcome rate (modified Rankin scale score > 4) assessed at discharge (p = 1.000) and 3 months after admission (p = 0.688) was similar between the two groups. However, 1 month after admission, the mortality rate of the hypothermia group (20.0 %) was remarkably lower than that of the control group (46.8 %) (p = 0.025). Multivariate logistic regression showed the therapeutic hypothermia was the most effective treatment for decreasing the mortality (OR = 4.86, P = 0.023). ConclusionMild hypothermia treatment appears to be feasible and safe for patients with poor-grade SAH. The study supports mild hypothermia treatment and its neuroprotective effects in patients with poor-grade SAH.

Perioperative Hypothermia Is Associated With Increased 30-Day Mortality in Hip Fracture Patients in the United Kingdom: Α Systematic Review and Meta-analysis.

To undertake a systematic review and meta-analysis to determine the relationship between perioperative hypothermia and mortality after surgery for hip fracture. A systematic literature search of Medline, EMBASE, CINAHL, and Cochrane CENTRAL databases was performed using the Cochrane methodology for systematic reviews with no publication year limit. Only studies available in the English language were included. Predetermined inclusion criteria were patients of any age with a hip fracture, exposure was their body temperature and outcome was mortality rate. Any comparative study design was eligible. The quality of selected studies was assessed according to each study design with the Methodological Index for Non-Randomised Studies (MINORS) used for all the retrospective comparative studies. The GRADE approach was used to assess the quality of evidence. A meta-analysis was conducted using a random-effects model. The literature search identified 1016 records. After removing duplicates and those not meeting inclusion criteria, 3 studies measuring 30-day mortality were included. All included studies were carried out in the United Kingdom. The mortality rate was higher in the hypothermic groups as compared with the normothermic group in all the studies, with the difference being significant in 2 of the studies (P < 0.0001). The meta-analysis showed that low body temperature was associated with an increased mortality risk (estimated odds ratio: 2.660; 95% confidence interval: 1.948-3.632; P < 0.001) in patients undergoing surgery for hip fracture. This study shows that low body temperature in hip fracture patients is associated with an increased 30-day mortality risk in the United Kingdom. Randomized control trials are required to determine whether the association between perioperative hypothermia in hip fracture patients and mortality is causal. Nevertheless, based on this analysis, we urge the maintenance of normal body temperature in the perioperative period to be included in national hip fracture guidelines. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Surgical Site Infection in Thoracic Surgery Is Not Associated With Perioperative Hypothermia.

Introduction: The Surgical Care Improvement Project (SCIP) added the SCIP-Inf-10 measure to mandate that all surgical patients have perioperative temperature management to reduce surgical site infection. While the basis of this measure originated in colorectal surgery, we hypothesized that this would also apply to thoracic surgery patients.Methods: This was a retrospective single-center pilot study reviewing two years of thoracic surgery cases for the incidence and duration of hypothermia during the operation and surgical site infection occurring within 30 days. Hypothermia was defined as a core temperature of < 36° C. Results: A total of 317 patients were included in the study. Sixty-two percent of patients were identified as hypothermic. The average intraoperative temperature was 35.4°C ± 0.8°C in the hypothermic group and 36.4°C ± 0.3°C in the normothermic group. There were four surgical site infections in the study with three cases from the <36°C group (p = 1). There was no difference in average post-anesthesia care unit length of stay between the groups. The average hospital length of stay was 5.5 ± 5.2 days for the hypothermic group and 8.6 ± 12.8 days for the normothermic group (p=0.0024).Conclusion: Perioperative hypothermia was common in thoracic surgery and did not have a negative impact on surgical site infection.

Water Rewarming After Seawater Hypothermia Mitigates IL-1β in Both Intestinal Tissue and Blood.

In this study, the rat models of severe hypothermia induced by seawater immersion were established in artificial seawater immersion at 15°C for 5 hours. With the rewarming measurement of 37°C water bath, the rewarming effects were evaluated by monitoring basic vital signs and dynamically detecting intestinal inflammation cytokines. Fifty Sprague-Dawley rats were randomly divided into five groups including the control group (group C), hypothermia group (group H), 2-hour rewarming group (group R2), 6-hour rewarming group (group R6), and 12-hour rewarming group (group R12), with 10 in each group. The basic vital signs of rats (i.e., core temperature, respiration, heart rate, and muscle tremor) were constantly recorded. The inflammatory factors were detected in the intestinal tissue via a protein chip GSR-CAA-67 of Innopsys, and the verification by reverse transcription-quantitative polymerase chain reaction. The levels of cytokines (interleukin IL-1β, IL-6, and IL-10) were detected from blood samples collected at the end of the observation period via enzyme-linked immunosorbent assay. The expression landscape of IL-1β in the intestinal tissue was validated by immunohistochemistry. Five hours of immersion in artificial seawater at 15°C successfully induced severe hypothermia of rats. After 2 hours of constant water bath rewarming at 37°C, the basic vital signs recovered to the normal level and maintained stably as well as the acute inflammatory reaction alleviated effectively, which indicated that 37°C of water immersion rewarming had the potential to be a suitable method for early treatment of water immersion hypothermia. After the process of hypothermia, several inflammatory cytokines of rats in rewarming groups changed distinctly with IL-1β, showing the most significant variations compared with group C, which confirmed IL-1β as a potential monitoring biomarker referring to the therapeutic effect of rewarming for severe hypothermia caused by seawater immersion.

Depolarization time and extracellular glutamate levels aggravate ultraearly brain injury after subarachnoid hemorrhage

Early brain injury after aneurysmal subarachnoid hemorrhage (SAH) worsens the neurological outcome. We hypothesize that a longer duration of depolarization and excessive release of glutamate aggravate neurological outcomes after SAH, and that brain hypothermia can accelerate repolarization and inhibit the excessive release of extracellular glutamate and subsequent neuronal damage. So, we investigated the influence of depolarization time and extracellular glutamate levels on the neurological outcome in the ultra-early phase of SAH using a rat injection model as Experiment 1 and then evaluated the efficacy of brain hypothermia targeting ultra-early brain injury as Experiment 2. Dynamic changes in membrane potentials, intracranial pressure, cerebral perfusion pressure, cerebral blood flow, and extracellular glutamate levels were observed within 30 min after SAH. A prolonged duration of depolarization correlated with peak extracellular glutamate levels, and these two factors worsened the neuronal injury. Under brain hypothermia using pharyngeal cooling after SAH, cerebral perfusion pressure in the hypothermia group recovered earlier than that in the normothermia group. Extracellular glutamate levels in the hypothermia group were significantly lower than those in the normothermia group. The early induction of brain hypothermia could facilitate faster recovery of cerebral perfusion pressure, repolarization, and the inhibition of excessive glutamate release, which would prevent ultra-early brain injury following SAH.

Hypothermic versus Normothermic Temperature Control after Cardiac Arrest

BackgroundThe evidence for temperature control for comatose survivors of cardiac arrest is inconclusive. Controversy exists as to whether the effects of hypothermia differ per the circumstances of the cardiac arrest or patient characteristics.MethodsAn individual patient data meta-analysis of the Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest (TTM) and Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trials was conducted. The intervention was hypothermia at 33°C and the comparator was normothermia. The primary outcome was all-cause mortality at 6 months. Secondary outcomes included poor functional outcome (modified Rankin scale score of 4 to 6) at 6 months. Predefined subgroups based on the design variables in the original trials were tested for interaction with the intervention as follows: age (older or younger than the median), sex (female or male), initial cardiac rhythm (shockable or nonshockable), time to return of spontaneous circulation (above or below the median), and circulatory shock on admission (presence or absence).ResultsThe primary analyses included 2800 patients, with 1403 assigned to hypothermia and 1397 to normothermia. Death occurred for 691 of 1398 participants (49.4%) in the hypothermia group and 666 of 1391 participants (47.9%) in the normothermia group (relative risk with hypothermia, 1.03; 95% confidence interval [CI], 0.96 to 1.11; P=0.41). A poor functional outcome occurred for 733 of 1350 participants (54.3%) in the hypothermia group and 718 of 1330 participants (54.0%) in the normothermia group (relative risk with hypothermia, 1.01; 95% CI, 0.94 to 1.08; P=0.88). Outcomes were consistent in the predefined subgroups.ConclusionsHypothermia at 33°C did not decrease 6-month mortality compared with normothermia after out-of-hospital cardiac arrest. (Funded by Vetenskapsrådet; ClinicalTrials.gov numbers NCT02908308 and NCT01020916.)

Thyroid Function in Neonates with Hypoxic Ischemic Encephalopathy.

We aimed to examine heel prick (capillary) and serum thyroid function test (TFT) results in neonates with hypoxic ischemic encephalopathy (HIE) to evaluate the effect of asphyxia and therapeutic hypothermia (TH) on thyroid functions. This retrospective chart review included infants who were born after 34 weeks of gestation, were diagnosed and treated for HIE. The patients were divided into those who did and did not undergo TH and the groups were compared in terms of demographic characteristics, laboratory results, capillary thyroid-stimulating hormone (cTSH) levels, and serum thyroid-stimulating hormone (TSH) and free thyroxine (fT4) levels. A total of 111 neonates were included in the study. There was no difference between the TH group (n = 90) and the nonhypothermia group (n = 21) in terms of median gestational age (38.3 ± 2.1 weeks vs. 38.6 ± 1.8 weeks, p = 0.42) or birth weight (3182 ± 509 g vs. 3174 ± 573 g, p = 0.72). Serum TFT was performed at a median of 10 days (range, 2-43) and capillary TSH analyzed at a median of 6 days (range, 1-26). Capillary TSH at 96 hours was analyzed in 36 patients in the TH group and 19 patients in the nonhypothermia group. Serum TSH and fT4 levels were similar in both groups (p = 0.29, p = 0.1). Overall cTSH and cTSH obtained in the first 4 days were 2.2 (0.5-10) and 4.3 (0.5-94), p = 0.059; 2 (0.5-22) and 5 (0.5-94), p = 0.04, respectively, whereas cTSH obtained after day 4 was similar in both groups (p = 0.058). Abnormal serum TSH (>5.5 mU/mL) was more frequent in the hypothermia group (44.4% vs. 19%, p = 0.026). Our results suggest that TH may cause some alterations on TFTs. Therefore, it may be reasonable to repeat TSH screening after TH.

Systematic review exploring the effect of therapeutic hypothermia on patients with intracranial hypertension.

Background: Intracranial hypertension is found in patients with various neurological and neurosurgical conditions such as subarachnoid hemorrhage (more than 50% of the patients have intracranial pressure > 20 mmHg at some point during their hospital stay), traumatic brain injury, and stroke. Various modalities are used to control intracranial hypertension, therapeutic hypothermia is one of them. This systematic review aims to assess the efficacy of therapeutic hypothermia in controlling intracranial hypertension in an adult patient.Methods: A systematic review of the literature published between one patient 1990 and 2020 was conducted. Four databases were searched including CINAHL, PubMed, the Cochrane Library, and EMBASE using keywords traumatic brain injury, intracranial pressure, randomized and controlled trials, and the effect of therapeutic hypothermia on intracranial hypertension.Results: All of the studies included in this review were randomized controlled trials. Most of the studies provided their sample demographics. Sample sizes ranged from 14 to 501. Of the 12 studies, five of them were from the United Kingdom, three of them were from China, two from North America, one from India, and one from Japan.Conclusion: Treating intracranial hypertension with therapeutic hypothermia may be beneficial according to a few studies but it is also associated with many adverse effects. Both the groups suffered from adverse events which were higher in the hypothermic group. However, these adverse events can be managed in any health-care setting. To treat the patients with therapeutic hypothermia, one (the managing team) should be competent enough to manage the adverse effects.