The Effect of Active Warming Before Total Knee Arthroplasty on Intraoperative Body Temperature and Comfort: A Randomized Control Trial.

PURPOSE: This study was conducted to determine the effect of active warming on intraoperative body temperature and comfort before total knee arthroplasty. DESIGN: This study was a randomized controlled trial designed according to the Consolidated Standards of Reporting Trials. METHODS: The study was conducted on 54 patients in a public hospital in Türkiye. In the study, patients in the intervention group were prewarmed for 30 minutes before surgery. The patients in the intervention and control groups were warmed with a warming bed during the surgery. FINDINGS: In this study, the first entry temperature to the operating room after anesthesia induction and the mean body temperature of the patients in the intervention group were higher than the control group. The mean comfort score of the patients in the intervention group was higher than the control group. CONCLUSIONS: As a result of this study, we found that the combination of preoperative prewarming and intraoperative warming reduced the decrease in the patient's body temperature and increased the comfort.

Effects of different forced-air warming systems on the core temperature of patients: a manikin and multi-center clinical study.

BACKGROUND: The use of forced-air warming (FAW) blankets is widely recognized for preventing shivering and hypothermia in patients under general anesthesia. Various types of products are currently available for hospitals, and we have conducted a preliminary evaluation of insulation equipment based on expert opinions and initial parameters. However, we lack real-world experiments and accurate clinical data to validate these parameters and the accuracy of our decision-making results. This study aims to confirm the effectiveness of different FAW systems by assessing the thermal protection and operational characteristics of the equipment in both experimental and clinical settings, thereby enhancing our evaluation database. METHODS: In the manikin test, we conducted six tests including heat distribution and heating rate, heater outlet temperature stability, etc. In the clinical study, patients were randomly assigned to four groups [Group A (Bair Hugger Therapy, 3 M, St. Paul, MN, USA; 63500); Group B (EQUATOR® level I, Smith Medical ASD, MN, USA; Snuggle Warm, SW-2013); Group C (Jiang Men Da Cheng Medical Devices Co., Ltd, China; IOB-006); and Group D (Shang Hai Nest Tech Medical Materials Co., Ltd, China; BH-017)], with each group comprising 30 individuals. At the start of anesthesia induction, the FAW blanket was activated and set to 43 °C until the completion of surgery. The primary endpoint was the average core body temperature during surgery. Secondary endpoints included hemodynamic and surgical variables, adverse events, and recovery metrics. RESULTS: In the manikin test, the observed results of the experimental parameters (heat distribution, air pressure difference, and hole observation test) for Group A are superior to those of the other groups. In the clinical study, although the mean perioperative core body temperature remained above 36 °C across all groups [Group A: 36.31 ± 0.04; Group B: 36.26 ± 0.06; Group C: 36.17 ± 0.03; Group D: 36.25 ± 0.05], patients in Group A maintained higher temperatures compared to the other groups (p < 0.001). CONCLUSIONS: Among patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia, all four FAW systems effectively prevented perioperative hypothermia. However, the system in Group A minimized heat loss more effectively than the others, providing superior thermal protection. TRIAL REGISTRATION: ChiCTR2200065394, 03/11/2022.

Peripheral warming for prevention of hypothermia in small dogs during soft tissue surgery: A randomized controlled trial.

OBJECTIVE: To evaluate the effects of wrapping the extremities of small dogs with table leg covers to prevent hypothermia during anesthesia. STUDY DESIGN: Randomized parallel-group study. ANIMALS: A total of 60 adult dogs with a body mass <15 kg anesthetized for soft tissue surgery. METHODS: Dogs were randomly assigned to one of two groups. The control group received routine intraoperative thermal support, while the limb-wrapping group had their peripheral limbs covered with table leg covers up to the mid-metacarpal/metatarsal region, in addition to routine thermal support. Rectal temperature during anesthesia was recorded and compared between the two groups. Data analyses were performed using Student's t-test for rectal temperature, Fisher's exact test for hypothermia incidence and analysis of covariance for the effect of limb-wrapping while taking other factors into account. RESULTS: Thirty dogs were included per group. Rectal temperature did not differ between the groups at the time of intubation, but it was significantly higher in the limb-wrapping group (36.7 ± 1.0 °C) than in the control group (35.9 ± 0.8 °C) at the end of surgery (p = 0.003). The mean difference was 0.81 °C (95% confidence interval of mean difference 0.33-1.29 °C). The incidence of hypothermia (<37.0 °C) was significantly lower in the limb-wrapping group than in the control group (19/30 versus 28/30 dogs, respectively; p = 0.010). CONCLUSIONS: For dogs with body masses <15 kg, limb-wrapping with table leg covers slowed the reduction in intraoperative rectal temperature. Limb-wrapping is inexpensive and easy to perform, making it a practical method for minimizing hypothermia during anesthesia in small dogs undergoing soft tissue surgery. CLINICAL RELEVANCE: Peripheral warming with table leg covers has the potential to reduce hypothermia during soft tissue surgery in small dogs.

Mild therapeutic hypothermic protection activates the PI3K/AKT signaling pathway to inhibit TRPM7 and suppress ferroptosis induced by myocardial ischemia­reperfusion injury.

The present study aimed to investigate the role of PI3K­mediated ferroptosis signaling induced by mild therapeutic hypothermia (MTH), which was defined as a temperature of 34˚C, in protecting against myocardial ischemia-reperfusion (I/R) injury (MIRI). To meet this aim, H9C2 cells underwent hypoxia­reperfusion (H/R) and/or MTH. The MTT assay was used to assess cell viability, cytotoxicity was measured using a lactate dehydrogenase cytotoxicity assay, and Annexin V­FITC/PI flow cytometric analysis was used to analyze early and late cell apoptosis. In addition, 84 healthy adult male Sprague­Dawley rats were randomly divided into seven groups (n=12), and underwent I/R and various treatments. Hemodynamics were monitored, and the levels of myocardial injury marker enzymes and oxidative stress markers in myocardial tissue were measured using ELISA. The expression levels of PI3K, AKT, transient receptor potential cation channel subfamily M member 7 (TRPM7), glutathione peroxidase 4 (GPX4) and acyl­CoA synthetase long chain family member 4 (ACSL4) in animals and cells were measured using western blot analysis. These experiments revealed that MTH could effectively reduce myocardial infarct size, improve hemodynamic performance following MIRI and suppress myocardial apoptosis, thereby contributing to the recovery from H/R injury. Mechanistically, MTH was revealed to be able to activate the PI3K/AKT signaling pathway in cells, upregulating GPX4, and downregulating the expression levels of TRPM7 and ACSL4. Treatment with 2­aminoethoxydiphenyl borate (an inhibitor of TRPM7) could further strengthen the myocardial protective effects of MTH, whereas treatment with erastin (promoter of ferroptosis) and wortmannin (inhibitor of PI3K) led to the effective elimination of the myocardial protective effects of MTH. Compared with in the I/R group, the PI3K/AKT activation level and the expression levels of GPX4 were both significantly increased, whereas the expression levels of TRPM7 and ACSL4 were significantly decreased in the I/R + MTH group. Taken together, the results of the present study indicated that MTH may activate the PI3K/AKT signaling pathway to inhibit TRPM7 and suppress ferroptosis induced by MIRI.

Moderate hypothermia circulatory arrest as a brain-protective strategy for type A aortic dissection.

OBJECTIVES: Brain-protective strategies for acute type A aortic dissection (TAAD) remain controversial. Moderate hypothermia circulatory arrest (MHCA) without cerebral perfusion is not commonly used. However, we aimed to assess its safety and efficacy in 358 patients who underwent hemiarch replacement with MHCA for acute type A aortic dissection at our institution from August 2012 to August 2022. METHODS: Clinical outcomes were compared according to circulatory arrest time [≤15 min (S group, n = 52) vs ≥16 min (L group, n = 306)]. The primary outcome was postoperative stroke. RESULTS: The S group had more older patients (72.5 vs 68.8 years; P = 0.04), a greater incidence of carotid artery malperfusion (21% vs 11%; P = 0.043) and a lower body mass index (21.7 vs 23.6 kg/m2; P < 0.01) and hemodynamic instability (3.8% vs 16%; P = 0.02) than the L group. The incidence of postoperative stroke (7.7% vs 12%; P = 0.33) and the rate of 30-day mortality (5.8% vs 6.5%; P = 0.83) did not significantly differ between groups. After adjusting for all potential confounding factors pre- and intraoperatively, there was no significant difference in postoperative outcomes between groups. CONCLUSIONS: MHCA alone for TAAD had comparable postoperative outcomes with circulatory arrest times under and over 15 min. However, longer arrest times were associated with a higher risk of stroke.

Excessive autophagy-inducing and highly penetrable biomineralized bacteria for multimodal imaging-guided and mild hyperthermia-enhanced immunogenic cell death.

The tumor microenvironment, characterized by hypoxia, supports the efficacy of anaerobic bacteria like attenuated S. typhimurium in cancer therapies. These bacteria target and penetrate deep tumor regions, significantly reducing tumor size but often lead to tumor regrowth due to limited long-term efficacy. To enhance the therapeutic impact, a novel biohybrid system, S@UIL, has been developed by coating S. typhimurium with a zirconium-based nanoscale metal-organic framework (UiO-66-NH2) loaded with indocyanine green (ICG) and luteolin (LUT). This system maintains the bacteria's tumor-targeting ability while increasing the penetration and therapeutic effectiveness through excessive autophagy and mild hyperthermia. In a subcutaneous colon cancer model, the integration of LUT and ICG promotes autophagic cell death and photothermal sensitization, leading to the release of damage-associated molecular patterns (DAMPs). These DAMPs activate immune responses through dendritic cells and T-cells, enhancing immunogenic cell death (ICD) and potentially reducing immune evasion by tumors. This single-administration approach also integrates multimodal imaging capabilities, providing a promising strategy for improved tumor ICD induction and cancer progression inhibition.

Effect of Deep Hypothermia (18°C) on Dioxygen Metabolism During Pulmonary Thromboendarterectomy Surgery.

OBJECTIVES: The aim of this physiological pilot study was to investigate the effect of deep hypothermia on oxygen extraction (OE) and consumption (VO2) in normothermic conditions (36-37°C), and at different stages of cooling: 30°C, 25°C, and 18°C. DESIGN: For 3 months, a prospective study was conducted on patients who underwent pulmonary thromboendarterectomy. SETTINGS: This was a single-center study done in a university teaching hospital. PARTICIPANTS: Patients who underwent pulmonary thromboendarterectomy during the inclusion period. INTERVENTIONS: Hemodynamic and biological data were recorded from arterial and venous blood gas samples withdrawn first at normothermia, then at 30°C, 25°C, and 18°C. MEASUREMENTS AND MAIN RESULTS: 24 patients were included in the final analysis. Indexed VO2 decreased from 65.9 mL to 25.1 mL of O2/min/m2 between 36°C and 18°C (p < 0.001). The OE decreased from 18% to 9% between 36°C and 18°C (p < 0.001). At normal temperature and 18°C, the median venoarterial difference of O2 bound to hemoglobin was 2.22 [1.68-2.58] and 0.03 mL [0.01-0.07] of O2/100 mL of blood, respectively (p < 0.001). Whereas the median venoarterial differences in dissolved O2 were 0.78 [0.66-0.92] and 1.09 mL [1.03-1.32] of O2/100 mL of blood, respectively (p = 0.0013). CONCLUSION: There were VO2 and OE decreases of more than half their baseline values at 18°C. Given that metabolic needs are essentially supplied by dissolved O2 during cooling from 30°C to 18°C, the authors suggest that PaO2 should be increased during the period of cooling and/or deep hypothermia to prevent hypoxia.

Hipotermia terapéutica: estudio descriptivo de una cohorte de 10 años en un hospital público de alta complejidad / Therapeutic hypothermia: A descriptive, cohort study conducted over 10 years at a tertiary care public hospital

Introducción. La hipotermia terapéutica (HT) reduce el riesgo de muerte o discapacidad en niños con encefalopatía hipóxico-isquémica (EHI) moderada-grave. Objetivo. Describir una población de pacientes con EHI que requirió HT y su evolución hasta el alta hospitalaria. Población y métodos. Estudio descriptivo de cohorte retrospectivo. Se analizaron todos los pacientes que ingresaron a HT entre 2013 y 2022. Se evaluaron datos epidemiológicos, clínicos, de monitoreo, tratamiento, estudios complementarios y condición al alta. Se compararon los factores de riesgo entre pacientes fallecidos y sobrevivientes, y de estos, los que requirieron necesidades especiales al alta (NEAS). Resultados. Se incluyeron 247 pacientes. Mortalidad: 11 %. Evento centinela más frecuente: período expulsivo prolongado (39 %). Inicio del tratamiento: mediana 5 horas de vida. Convulsiones: 57 %. Eritropoyetina intravenosa: 66,7 %. Patrón anormal de monitoreo de función cerebral: 52 %. Normalización del monitoreo: mediana 24 horas. Resonancia magnética patológica: 42 %. Variables predictoras de mortalidad: Sarnat y Sarnat grave, y ecografía patológica al ingreso. Conclusión. La mortalidad global fue del 11 %. Las derivaciones aumentaron en forma más evidente a partir del año 2018. El horario de inicio de HT fue más tardío que en reportes anteriores. Los signos neurológicos de gravedad según la escala de Sarnat y Sarnat y la ecografía cerebral basal patológica fueron predictores independientes de mortalidad al alta. Los pacientes con NEAS presentaron normalización del trazado del electroencefalograma de amplitud integrada más tardío. El hallazgo más frecuente en la resonancia fue la afectación de los ganglios basales. No se encontraron diferencias clínicas ni de complicaciones estadísticamente significativas entre los pacientes que recibieron eritropoyetina.

Introduction. Therapeutic hypothermia (TH) reduces the risk of death or disability in children with moderate to severe hypoxic ischemic encephalopathy (HIE). Objective. To describe a population of patients with HIE that required TH and their course until discharge. Population and methods. Retrospective, descriptive, cohort study. All patients admitted to TH between 2013 and 2022 were studied. Epidemiological, clinical, monitoring, and treatment data were assessed, together with supplementary tests and condition at discharge. Risk factors were compared between deceased patients and survivors; and, among the latter, those requiring special healthcare needs (SHCN) at discharge. Results. A total of 247 patients were included. Mortality: 11%. Most common sentinel event: prolonged second stage of labor (39%). Treatment initiation: median of 5 hours of life. Seizures: 57%. Intravenous erythropoietin: 66.7%. Abnormal pattern in brain function monitoring: 52%. Normalization of monitoring: median of 24 hours. Pathological magnetic resonance imaging: 42%. Predictor variables of mortality: severe Sarnat and Sarnat staging and pathological ultrasound upon admission. Conclusion. The overall mortality rate was 11%. Referrals increased more markedly since 2018. The time of TH initiation was later than in previous reports. Severe neurological signs as per the Sarnat and Sarnat staging and a pathological baseline cranial ultrasound were independent predictors of mortality at discharge. Patients with SHCN at discharge showed a normalized tracing in the amplitude-integrated electroencephalography performed later. The most common finding in the magnetic resonance imaging was basal ganglia involvement. No statistically significant differences were observed in terms of clinical characteristics or complications among patients who received erythropoietin.

Experimental study of the effectiveness of warm ischemia and cold ischemia during testis-sparing surgery in rats.

INTRODUCTION: The postpubertal effects of testis-sparing surgery on prepubertal testicular tumors are not fully understood. OBJECTIVE: In this study, we aimed to evaluate the effect of different durations of warm and cold ischemia during a rat prepubertal testis-sparing surgery model on the ischemic and contralateral normal testes in the postpubertal period. STUDY DESIGN: The study encompassed a group of 54 male rats in the prepubertal stage who were then arranged to be put into nine groups: sham (Sh), control-cold (Cc), control-biopsy (Cb), 30, 60 or 90min warm ischemia (WIb30,WIb60,WIb90) and cold ischemia (CIb30,CIb60,CIb90). In the ischemia groups, a microvascular clamp was applied to the right spermatic cord, then testicular biopsy was taken. In the cold ischemia groups, the testicles were preserved in sterile ice mud. After the experiment, the rats were observed for 4 weeks to pinpoint any changes during their progression into the post-pubertal period. Bilateral orchiectomy materials were examined histopathologically, and Johnsen scores were used to evaluate postpubertal fertility potential. RESULTS: In our investigation, rats in all groups exhibited similar weight gains. The postpubertal size of the right testis in the testicular biopsy groups was found to be smaller compared to the remaining groups. In the warm ischemia group, testicular atrophy occurred after ischemic duration exceeding 30 min. Conversely, no testicular atrophy was observed in the cold ischemia groups. The dimensions of the rats' left testicles were similar. On histopathology, right testicular Johnsen scores were significantly lower in the warm ischemic groups than in the cold ischemic groups. DISCUSSION: Our study is the first to investigate the postpubertal effects of varying durations of warm and cold ischemia in a prepubertal testis-sparing surgery model. In our study, the Johnsen scores of testes subjected to 30, 60, and 90 min of ischemia were found to be higher in the cold ischemia groups compared to the warm ischemia groups. As the ischemia duration prolonged, a discernible progression of testicular atrophy was observed in the warm ischemia groups, contrasting with the sustained stability of testicular sizes in the cold ischemia groups. CONCLUSIONS: Warm ischemia applied to the testis causes damage to the testicle within the first 30 min and leads to atrophy after 30 min. In the cases of warm ischemia, both the Johnsen scores, which serve as indicators of post-pubertal fertility, and the testicular size decline in parallel with the duration of ischemia.

Estimation of the difference between peritoneal microenvironment and core body temperature during laparoscopic surgery - a prospective observational study.

Maintaining patients' temperature during surgery is beneficial since hypothermia has been linked with perioperative complications. Laparoscopic surgery involves the insufflation of carbon dioxide (CO2) into the peritoneal cavity and has become the standard in many surgical indications since it is associated with better and faster recovery. However, the use of cold and dry CO2 insufflation can lead to perioperative hypothermia. We aimed to assess the difference between intraperitoneal and core temperatures during laparoscopic surgery and evaluate the influence of duration and CO2 insufflation volume by fitting a mixed generalized additive model. In this prospective observational single-center cohort trial, we included patients aged over 17 with American Society of Anesthesiology risk scores I to III undergoing laparoscopic surgery. Anesthesia, ventilation, and analgesia followed standard protocols, while patients received active warming using blankets and warmed fluids. Temperature data, CO2 ventilation parameters, and intraabdominal pressure were collected. We recruited 51 patients. The core temperature was maintained above 36 °C and progressively raised toward 37 °C as pneumoperitoneum time passed. In contrast, the intraperitoneal temperature decreased, thus creating a widening difference from 0.4 [25th-75th percentile: 0.2-0.8] °C at the beginning to 2.3 [2.1-2.3] °C after 240 min. Pneumoperitoneum duration and CO2 insufflation volume significantly increased this temperature difference (P < 0.001 for both parameters). Core vs. intraperitoneal temperature difference increased linearly by 0.01 T °C per minute of pneumoperitoneum time up to 120 min and then 0.05 T °C per minute. Each insufflated liter per unit of time, i.e. every 10 min, increased the temperature difference by approximately 0.009 T °C. Our findings highlight the impact of pneumoperitoneum duration and CO2 insufflation volume on the difference between core and intraperitoneal temperatures. Implementing adequate external warming during laparoscopic surgery effectively maintains core temperature despite the use of dry and unwarmed CO2 gases, but peritoneal hypothermia remains a concern, suggesting the importance of further research into regional effects.Trial registration: Clinicaltrials.gov: NCT04294758.

Impact of Prewarming on Maintaining Perioperative Body Temperature: A Randomized Clinical Trial.

PURPOSE: To determine the prewarming effect on body temperature in the perioperative period of patients undergoing conventional abdominal surgery and the level of thermal comfort. DESIGN: A randomized controlled clinical trial. METHODS: A Brazilian oncology hospital located in São Paulo. A total of 99 patients aged 18 years or over undergoing elective conventional abdominal surgeries, with a minimum duration of 1 hour of anesthesia. The study was carried out from 2019 to 2021. Patients were randomized into 3 groups: prewarming with a blanket and cotton sheet (control; n = 33); prewarming with a forced-air warming system for 20 minutes (intervention 1; n = 33); prewarming with a forced-air warming system for 30 minutes (intervention 2; n = 33). Central temperature was measured by a zero-heat-flux temperature sensor every 20 minutes from the preoperative period until the surgery end time. The level of thermal comfort was determined through self-report during the preanesthetic and postanesthetic periods. FINDINGS: There was a significant difference between the temperatures between the groups (P = .048), with evidence of greater benefit in maintaining the temperature in the group that received the prewarming intervention for 20 minutes. There was no significant difference between the percentage of temperatures below 36 °C among the groups (P = .135). Patients in the intervention groups were more comfortable during the postanesthetic recovery period than those in the control group (P = .048). Only 7 (8.24%) patients had postoperative chills (P = .399) and more than half of these incidents occurred in the control group (4; 13.3%). CONCLUSIONS: Prewarming for 20 minutes obtained the best results, showing the lowest average of temperature episodes below 36 °C during the intraoperative period and greater thermal comfort as reported by patients.

Intraoperative temperature management during emergency cesarean section: a retrospective observational study.

BACKGROUND: Intraoperative hypothermia is a common complication during cesarean section (C-section) and associated with the high maternal mortality and morbidity. This study aimed to explore the risk factors associated with the incidence of intraoperative hypothermia in women who underwent emergency C-section deliveries. METHODS: We retrospectively enrolled women who underwent emergency cesarean deliveries from August 2022 to Dec 2023 at Suzhou Municipal Hospital of Anhui Province. Baseline characteristics, thermal status, and perioperative information were extracted. Hypothermia was defined as the onset of a core temperature below 36 °C. Data were compared between patients with and without a hypothermia during surgery. Logistic regression analyses were performed to determine the risk factors for low-temperature-status. RESULTS: Overall, 87 patients were included, and 30 underwent hypothermia during surgery. For women with a normal temperature status, women in the hypothermia group had a lower incidence of receiving active warming methods (52.6% vs. 30%, P = 0.044). In the logistic regression model involving core temperature, a pre-surgery core temperature < 36.5 °C (OR 4.22, 95% CI 1.13-15.63, p = 0.032) and a long surgery duration (per 10 min, OR 1.97, 95% CI 1.24-3.11, p = 0.004) were associated with a high probability of hypothermia. Administering active warming methods to women can reduce the risk of experiencing a hypothermia during emergency C-sections (OR 0.19, 95% CI 0.05-0.63; p = 0.007). CONCLUSIONS: Hypothermia is common in emergency C-section deliveries. It is recommended that active warming methods should be applied to parturient undergoing emergency C-sections more proactively, especially for women who have a low baseline core temperature (< 36.5 °C) and are expected to have a long surgery duration.

Total aortic arch replacement with frozen elephant trunk technique for intramural haematoma of the thoracic aorta.

Presenting this video tutorial, we want to demonstrate a step-by-step surgical approach to acute intramural haematoma of the thoracic aorta without a definite entry tear. Limited by the aortic valve proximally, the intramural haematoma involved the aortic root, ascending aorta, aortic arch, including adjacent parts of supra-aortic branches, and descending aorta extending to the diaphragmatic level. The operative strategy involved urgent total aortic arch replacement with the frozen elephant trunk technique and anatomical reimplantation of the three supra-aortic vessels. The direct open over-the-wire technique was used to cannulate the right axillary artery, and standard venous cannulation was performed while brain protection was achieved with bilateral selective antegrade cerebral perfusion.

Therapeutic Effect of Superficial Scalp Hypothermia on Chemotherapy-Induced Alopecia in Breast Cancer Survivors.

Alopecia is a common adverse effect of neoadjuvant or adjuvant chemotherapy in patients with early breast cancer. While hair typically regrows over time, more than 40% of patients continue to suffer from permanent partial alopecia, significantly affecting body image, psychological well-being, and quality of life. This concern is a recognized reason why some breast cancer patients decline life-saving chemotherapy. It is critical for healthcare professionals to consider the impact of this distressing side effect and adopt supportive measures to mitigate it. Among the various strategies investigated to reduce chemotherapy-induced alopecia (CIA), scalp cooling has emerged as the most effective. This article reviews the pathophysiology of CIA and examines the efficacy of different scalp cooling methods. Scalp cooling has been shown to reduce the incidence of CIA, defined as less than 50% hair loss, by 50% in patients receiving chemotherapy. It is associated with high patient satisfaction and does not significantly increase the risk of scalp metastasis or compromise overall survival. Promising new scalp cooling technologies, such as cryogenic nitrogen oxide cryotherapy, offer the potential to achieve and maintain lower scalp temperatures, potentially enhancing therapeutic effects. Further investigation into these approaches is warranted. Research on CIA is hindered by significant heterogeneity and the lack of standardised methods for assessing hair loss. To advance the field, further interdisciplinary research is crucial to develop preclinical models of CIA, establish a uniform, internationally accepted and standardised classification system, and establish an objective, personalised prognosis monitoring system.

Kenneth Keown (1917-1985): Innovator in Early Cardiac Anesthesiology.

Kenneth Keown, MD, was a forward-thinking anesthesiologist who developed techniques to allow the safe practice of cardiac anesthesia and opened the door for the future development of more complex intracardiac surgical procedures. His early successful protocols for cardiac anesthesiology and his wide-reaching education of others on these methods earned him the designation of "the grand old man of anesthesia for inside-the-heart surgery" at a young age. His contributions also extended to groundbreaking research in hypothermia, lidocaine uses as an antiarrhythmic, and advocacy for anesthesiology as a specialty. We highlight the accomplishments of Dr. Keown that may be unrecognized by those outside the field of cardiac anesthesiology, as they paved the way for the success of modern cardiac surgery.

Understanding the role of intraoperative hypothermia in perioperative opioid requirements in immediate implant-based breast reconstruction.

BACKGROUND: The relationship between perioperative temperatures and postoperative pain is unknown. The present study investigated the relationship of intraoperative hypothermia and perioperative opioid requirements after immediate implant-based breast reconstruction. METHODS: A retrospective chart review was conducted on patients undergoing immediate implant-based breast reconstruction from 2019-2023. Patients were classified into the hypothermic group (majority of procedure <36.0 °C) or normothermic group (majority of procedure ≥36.0 °C). Cumulative inpatient opioid requirements (morphine milli-equivalents [MMEs]) and frequency of patients requiring "high-dose opioids" (≥100 MMEs) were collected and compared between the groups. RESULTS: In total, 536 patients (835 breasts) were included, among whom 135 (25.1%) were hypothermic. The hypothermic group had lower mean intraoperative (88.4 vs. 99.1 MMEs, P = 0.007) and postoperative (45.6 vs. 56.8 MMEs, P = 0.006) than the normothermic group. Mean (B = 14.6, P = 0.004) and nadir (B = 10.4, P = 0.038) intraoperative temperatures directly predicted higher opioid requirements while higher percentages of the procedure time spent under 36 °C (B = -27.6, P = 0.004) predicted lower opioid requirements. The hypothermic group was associated with 66% decreased odds of requiring high-dose opioids after adjusting for differences in patient and operative characteristics (P = 0.007). CONCLUSION: Hypothermia is associated with decreased perioperative opioid requirements. Future studies should further investigate ideal temperature thresholds for warming protocols to minimize postoperative pain.

The effect of forced-air warming blanket position during spinal surgery on patients' intra-operative body temperature.

BACKGROUND: The use of body-warming systems is recommended by international anaesthesia societies for patients undergoing surgery. Limited research is however available on the influence of positioning of forced-air warming blankets for patients undergoing spinal surgery. This study aimed to investigate how patients' intra-operative body temperature was affected by the position of forced-air warming blankets while undergoing spinal surgery on a spinal table. DESIGN: A randomized comparative experimental study was conducted with 60 adult patients undergoing posterior spinal surgery. METHODS: Patients were randomized into full underbody (n = 30) or surgical access (n = 30) forced-air warming blanket groups. Intra-operative body temperature was recorded at regular time intervals. The student's T-test, Chi-square, and MANOVA tests were performed to determine the differences between the two groups. RESULTS: Intraoperative hypothermia was significantly lower in the full underbody group than in the surgical access group (p = 0.020). The change in body temperature differed significantly between the two groups from 15 min until 240 min, with a mean difference of 0.5 °C. CONCLUSION: The full underbody position of the forced-air warming blanket was effective for maintaining normal range core body temperature. The use of full underbody forced-air warming blanket for spinal surgery when patients are positioned on a spinal table in a prone position is recommended.

Non-circulatory arrest aortic arch replacement.

The definitive management of combined aortic arch and descending aortic pathologies such as aneurysms and dissections is either a single or staged operation associated with high morbidity and mortality. Stroke, kidney dysfunction, coagulopathy and high blood transfusion requirements are all affiliated with hypothermic circulatory arrest and prolonged cardiopulmonary bypass times. Considering the perilous nature of these operations, the authors describe a step-by-step zone 2 arch replacement as a staged frozen elephant trunk procedure, which provides an adequate landing zone for a later-placed endovascular stent yet maintains a short cardiopulmonary bypass time and no circulatory arrest.

Birth in the Operating Room for Immediate Cardiac Surgery: A Rare but Effective Strategy.

Background: With significant advancements in fetal cardiac imaging, patients with complex congenital heart disease (CHD) carrying a high risk for postnatal demise are now being diagnosed earlier. We sought to assess an interdisciplinary strategy for delivering these children in an operating room (OR) adjacent to a cardiac OR for immediate surgery or stabilization. Methods: All children prenatally diagnosed with CHD at risk for immediate postnatal hemodynamic instability and cardiogenic shock who were delivered in the operating room (OR) between 2012 and 2023 in which the senior author was consulted were included. Results: Eight patients were identified. Six (75%) patients were operated on day-of-life zero, all requiring obstructed total anomalous pulmonary venous return (TAPVR) repair. Of these six patients, 2 (33%) required a simultaneous Norwood procedure, 2 (33%) required pulmonary artery unifocalization and modified Blalock-Taussig-Thomas shunt, and 2 (33%) patients had repair of obstructed mixed TAPVR. The remaining 2 patients potentially planned for immediate surgery had nonimmune hydrops fetalis and went into cardiogenic shock at 12 and 72 hours postnatally, requiring a novel Norwood procedure with left-ventricular exclusion for severe aortic/mitral valve insufficiency. The median ventilation and inpatient durations were 19 [IQR: 11-26] days and 41 [IQR: 32-128] days, respectively. Three(38%) patients required one or more in-hospital reoperations. Subsequent staged procedures included Glenn (n = 5), Fontan (n = 3), biventricular repair (n = 2), ventricular assist device placement (n = 1), and heart transplant (n = 1). Median follow-up was 5.7 [IQR:1.3-7.8] years. The five-year postoperative survival was 88% (n = 7/8). Conclusion: While children with these diagnoses have historically had poor survival, the strategy of birth in the OR adjacent to a cardiac OR where emergent surgery is planned is a potentially promising strategy with excellent clinical outcomes. However, this is a high-resource strategy whose feasibility in any program requires thoughtful assessment.

Temperature control during pars plana vitrectomy.

PURPOSE: To evaluate the impact of temperature-controlled pars plana vitrectomy (PPV) on structural and functional outcomes in a rabbit eye model in vivo. METHODS: Ten healthy New Zealand White rabbits underwent temperature-controlled PPV in the right eye (group A), using a device specifically designed to heat the infusion fluid/air and integrated into the vitrectomy machine, and conventional PPV in the left eye (group B). Both eyes received ophthalmic examination and electroretinography (ERG) before and 1 week postoperatively. After 1-week ERG, rabbits were enucleated and then sacrificed. Histological and immunohistochemical examinations were performed on enucleated eyes and expression of glial fibrillary acidic protein (GFAP) and vimentin investigated. RESULTS: Postoperatively, only group B showed significantly decreased amplitude and increased latency of a-wave at 3 cd·s/m2 (p = 0.001 and 0.005, respectively). Significant increase of b-wave latency at 0.01 cd·s/m2 was detected in both groups (p = 0.019 and 0.023, respectively). Postoperatively, amplitude of oscillatory potentials (OPs) increased significantly in group A (p = 0.023) and decreased in group B. In both groups, OPs latency significantly increased at 1-week test (P < 0.05). A greater number of eyes without structural retinal alterations was detected in group A compared to group B (6 vs 5, respectively). GFAP expression was higher in group B than group A, even if the difference was not statistically significant. CONCLUSION: Temperature-controlled PPV resulted in more favorable functional and structural outcomes in rabbit eyes compared with conventional PPV, supporting the potential beneficial role of the intraoperative management of intraocular temperature in vitreoretinal surgery.