Recent Advances and Future Directions of Hypothermia Therapy for Traumatic Brain Injury

For severe traumatic brain injury (TBI) patients, no effective treatment method replacing hypothermia therapy has emerged, and hypothermia therapy still plays the major role. To increase its efficacy, first, early introduction is important. Since there are diverse pathologies of severe TBI, it is necessary to appropriately control the temperature in the hypothermia maintenance and rewarming phases by monitoring relative to the pathology. Currently, hypothermia is considered appropriate for severe TBI patients requiring craniotomy for removal of hematoma, while induced normothermia is appropriate for severe TBI patients with diffuse brain injury. Induced normothermia is expected to exhibit a cerebroprotective effect equivalent to hypothermia, as well as reduce the complexity of whole-body management and systemic complications. According to the Japan Neurotrauma Data Bank of the Japan Society of Neurotraumatology, the brain temperature was controlled in 43.9% of severe TBI patients (induced normothermia: 32.2%, hypothermia: 11.7%) in Japan. Brain temperature management was performed mainly in young patients, and the outcome on discharge was favorable in patients who received brain temperature management. Particularly, patients who need craniotomy for removal of hematoma were a good indication of therapeutic hypothermia. Improvement of therapeutic outcomes with widespread temperature management in TBI patients is expected.     

Therapeutic hypothermia and acute brain injury

Secondary brain injury has devastating effects on morbidity, mortality and good functional outcomes. Neuroprotection is multimodal, with decades of preclinical and small clinical studies showing the benefits of therapeutic hypothermia. The basic scientific principles have merit, yet large randomized controlled trials fail to show a clear benefit. This article will review the basic science – the practical aspects of delivering targeted temperature management and evaluate the evidence behind its use for acute brain injuries. With a lack of high-quality evidence for hypothermia, recent consensus statements are shifting the paradigm away from hypothermia to the maintenance of normothermia and prevention of pyrexia.     

Normothermic Cardiopulmonary Bypass Increases Heparin Requirements Necessary to Maintain Anticoagulation

Objective. With the practice of warm cardiopulmonary bypass (CPB) at our institution we have observed an apparent increase in heparin requirements. CPB temperature predictability affects pharmacokinetics and differences in drug metabolism can be expected. We hypothesized that heparin requirements would increase with increasing CPB temperature. Methods. Following Institutional Review Board approval, we reviewed the charts of 354 patients undergoing primary coronary artery bypass graft surgery. We recorded patient demographic data, CPB duration, heparin requirements, and temperature during CPB. CPB was conducted between 24 °C and 37 °C. The Spearman's correlation coefficient, Pearson chi-square, and rank-sum tests were used for data analysis. Results. Core temperature during CPB correlated with heparin requirements (r = 0.13, p < 0.02). However, CPB duration was shorter in warm patients than in cold patients (r = –0.455, p < 0.0001). Additional heparin requirements adjusted for duration of CPB (units/minute) were also significantly greater in the warm group (p = 0.018). Conclusions. Maintenance of adequate heparin anticoagulation during CPB is clinically important. Warm CPB patients required more heparin per minute than those undergoing cold CPB. More frequent assessment of anticoagulation and administration of additional heparin should be considered in patients undergoing warm CPB.     

Intensive care management of acute ischemic stroke

Despite the success of acute reperfusion therapies for the treatment of acute ischemic stroke, only a minority of patients receive such treatment. Even patients who receive reperfusion therapy remain at risk for further neuronal death through progressive infarction and secondary injury mechanisms. The goal of neurocritical care for the patient with acute ischemic stroke is to optimize long-term outcomes by minimizing the amount of brain tissue that is lost to these processes. This is accomplished by optimizing brain perfusion, limiting secondary brain injury, and compensating for associated dysfunction in other organ systems. Because of the rapid and irreversible nature of ischemic brain injury, it is crucial for best neurocritical care practices to begin as early as possible. Therefore, this chapter will discuss optimal, pragmatic neurocritical care management of patients with acute ischemic stroke during the "golden" emergency department hours from the perspective of the neurointensivist. Major topics include cerebral perfusion optimization; management of cerebral edema; post-thrombolytic care; acute anticoagulation; treatment of commonly associated cardiac and pulmonary complications; fluid, electrolyte and glucose management; the role of induced normothermia and therapeutic hypothermia; and prophylaxis against common complications.     

常温与低温体外循环在冠状动脉旁路移植术中的对比观察

[目的]对常温与低温体外循环(CPB)在冠状动脉旁路移植术(CABG)中进行比较。[方法]80例冠状动脉搭桥手术患者,随机分为常温(膀胱温度37℃)组和低温(膀胱温度28℃)组,其他麻醉和CPB方法一致。将两组麻醉时间、手术时间、麻醉药用量、清醒时间、输液输血量及血糖统计学处理。[结果]两组芬太尼、潘库溴胺用量相近,而咪唑安定的用量在低温组明显多于常温组(P<0.05)。常温组自动复跳例数明显多于低温组,低心排综合征发生例数明显少于低温组(P<0.05)。从CPB开始直至入ICU3h两组血糖均明显高于麻醉前(P<0.05),且在CPB中、CPB停机时、手术结束时、入ICU3h低温组的血糖高于常温组(P<0.05)。胰岛素用量低温组多于常温组(P<0.05)。[结论]常温CPB简便易行,CPB时间短,对心脏无不良影响;且对周身器官干扰小,恢复快,避免了低温对机体的危害。     

Reducing the risk of unplanned perioperative hypothermia

Maintaining normothermia is important for patient safety, positive surgical outcomes, and increased patient satisfaction. Causes of unplanned hypothermia in the OR include cold room temperatures, the effects of anesthesia, cold IV and irrigation fluids, skin and wound exposure, and patient risk factors. Nurses at Riddle Memorial Hospital in Media, Pennsylvania, performed a quality improvement project to evaluate the effectiveness of using warm blankets, warm irrigation fluids, or forced-air warming on perioperative patients to maintain their core temperature during the perioperative experience. Results of the project showed that 75% of patients who received forced-air warming perioperatively had temperatures that reached or were maintained at 36° C (96.8° F) or higher within 15 minutes after leaving the OR.     

Reflective Blankets Are as Effective as Forced Air Warmers in Maintaining Patient Normothermia During Hip and Knee Arthroplasty Surgery

Background

The use of forced air warming devices in the operating room has been shown to cause disruption of laminar airflow and a potential for increase in surgical site contamination. In contrast, conductive warming devices such as reflective blankets do not disrupt airflow and therefore have no potential for this increase in surgical site infection. However, some studies have shown them to be inferior to forced air warming devices in maintaining normothermia. We tested the hypothesis that the use of reflective blankets is as effective as forced air warming devices in maintaining intraoperative normothermia after adequate prewarming.