Induced Hypothermia to 4.2°C with Neurologically Intact Survival: A Forgotten Case Series.

The lowest recorded core temperature from which a person with accidental hypothermia has survived neurologically intact is 11.8°C in a 2-y-old boy. The lowest recorded temperature from which an adult has been resuscitated neurologically intact is 13.7°C in a 29-y-old woman. The lowest core temperature with survival from induced hypothermia has been quoted as 9°C. We discovered a case series (n=50) from 1961 in which 5 patients with core temperatures below 11.8°C survived neurologically intact. The lowest core temperature in this group was 4.2°C. The authors also presented cardiovascular and other physiologic data at various core temperatures. The patients in the case series showed a wide variation in individual physiological responses to hypothermia. It is not known whether survival from accidental hypothermia is possible with a core temperature below 11.8°C, but this case series suggests that the lower limit for successful resuscitation may be far lower. We advise against using core temperature alone to decide whether a hypothermic patient in cardiac arrest has a chance of survival.

Therapeutic hypothermia translates from ancient history in to practice.

Acute postasphyxial encephalopathy around the time of birth remains a major cause of death and disability. The possibility that hypothermia may be able to prevent or lessen asphyxial brain injury is a "dream revisited". In this review, a historical perspective is provided from the first reported use of therapeutic hypothermia for brain injuries in antiquity, to the present day. The first uncontrolled trials of cooling for resuscitation were reported more than 50 y ago. The seminal insight that led to the modern revival of studies of neuroprotection was that after profound asphyxia, many brain cells show initial recovery from the insult during a short "latent" phase, typically lasting ~6 h, only to die hours to days later during a "secondary" deterioration phase characterized by seizures, cytotoxic edema, and progressive failure of cerebral oxidative metabolism. Studies designed around this conceptual framework showed that mild hypothermia initiated as early as possible before the onset of secondary deterioration, and continued for a sufficient duration to allow the secondary deterioration to resolve, is associated with potent, long-lasting neuroprotection. There is now compelling evidence from randomized controlled trials that mild induced hypothermia significantly improves intact survival and neurodevelopmental outcomes to midchildhood.

Approaches for Therapeutic Temperature Management.

In concert with an evolution toward an increased awareness of the need to tightly manage temperature, the methods used to monitor and manipulate temperature have evolved from mercury-filled glass thermometers, alcohol baths, and ice packs into a high technology-driven multidisciplinary activity. The purpose of this article is to provide a brief overview of the historical development of temperature management and the primary tenets of each of the 3 phases (induction, maintenance, and rewarming), which are now recognized as crucial steps to ensure the safe practice of therapeutic temperature management.

Cardiac standstill and circulatory flow arrest in surgical treatment of intracranial aneurysms: a historical review.

Since the first surgery for an intracranial aneurysm in 1931, neurological surgeons have long strived to determine the optimal methods of surgical correction. Significant challenges of aneurysm clipping include intraoperative rupture and complex dome morphology. Hypothermia, cardiopulmonary bypass, pharmacologically induced hypotension, and cardiac standstill are a few of the methodologies historically and currently employed in the management of these issues. In the 1980s, significant advances in pharmacology and anesthesiology led to the use of agents such as adenosine for chemically induced hypotension and eventually complete circulatory arrest. Since the institution of the use of these agents, the traditional methods of circulatory arrest under conditions of hypothermia and cardiopulmonary bypass have fallen out of favor. However, there still exists a subset of technically difficult aneurysms for which cardiac standstill, both chemical and hypothermic, remains a viable therapeutic option. In this paper, the authors describe the history of cardiac standstill by both hypothermic and chemically induced means as well as provide examples in which these techniques are still necessary.

Clinical applications of targeted temperature management.

Targeted temperature management (TTM) has been investigated experimentally and used clinically for over 100 years. The initial rationale for the clinical application of TTM, historically referred to as therapeutic hypothermia, was to decrease the metabolic rate, allowing the injured brain time to heal. Subsequent research demonstrated the temperature dependence of diverse cellular mechanisms including endothelial dysfunction, production of reactive oxygen species, and apoptosis. Consequently, modern use of TTM centers on neuroprotection following focal or global neurologic injury. Despite a solid basic science rationale for applying TTM in a variety of disease processes, including cardiac arrest, traumatic brain injury, ischemic stroke, neonatal ischemic encephalopathy, sepsis-induced encephalopathy, and hepatic encephalopathy, human efficacy data are limited and vary greatly from disease to disease. Ten years ago, two landmark investigations yielded high-quality data supporting the application of TTM in comatose survivors of out-of-hospital cardiac arrest. Additionally, TTM has been demonstrated to improve outcomes for neonatal patients with anoxic brain injury secondary to hypoxic ischemic encephalopathy. Trials are currently under way, or have yielded conflicting results in, examining the utility of TTM for the treatment of ischemic stroke, traumatic brain injury, and acute myocardial infarction. In this review, we place TTM in historic context, discuss the pathophysiologic rationale for its use, review the general concept of a TTM protocol for the management of brain injury, address some of the common side effects encountered when lowering human body temperature, and examine the data for its use in diverse disease conditions with in-depth examination of TTM for postarrest care and pediatric applications.

[FIRST OPERATION ON OPEN HEART IN HYPOTHERMIA PERFORMED IN CROATIA IN 1957]. / PRVA OPERACIJA NA OTVORENOM SRCU U HIPOTERMIJI U HRVATSKOJ IZVEDENA 1957. GODINE.

On October 25, 1957, the first open heart surgery in hypothermia was performed in Zagreb, at the Department of Surgery, Dr. Ozren Novosel University Hospital (now Merkur University Hospital), in a female patient with pulmonary valve stenosis under the control of the eye and with interruption of venous circulation. It was the first such operation performed in hypothermia not only in Croatia, but probably in the territory of former Yugoslavia.

Hypothermia for acute spinal cord injury--a review.

OBJECTIVE: Spinal cord injury (SCI) is a catastrophic neurological event with no proven treatments that protect against its consequences. Potential benefits of hypothermia in preventing/limiting central nervous system injury are now well known. There has been an interest in its potential use after SCI. This article reviews the current experimental and clinical evidence on the use of therapeutic hypothermia in patients with SCI. METHODS: Review of literature. RESULTS: There are various mechanisms by which hypothermia is known to protect the central nervous system. Modest hypothermia (32°C-34°C) can deliver the potential benefits of hypothermia without incurring the complications associated with deep hypothermia. Several recent experimental studies have repeatedly shown that the use of hypothermia provides the benefit of neuroprotection after SCI. Although older clinical studies were often focused on local cooling strategies and demonstrated mixed results, more recent data from systemic hypothermia use demonstrate its safety and its benefits. Endovascular cooling is a safe and reliable method of inducing hypothermia. CONCLUSIONS: There is robust experimental and some clinical evidence that hypothermia is beneficial in acute SCI. Larger, multicenter trials should be initiated to further study the usefulness of systemic hypothermia in SCI.

Cooling mechanisms in laparoscopic partial nephrectomy: are really necessary?

OBJECTIVE: The purpose of this review is to provide an overview of the possibilities and drawbacks of the various possibilities of renal parenchymal cooling during laparoscopic partial nephrectomy and also give an outlook into future developments. METHODS: In January 2012 a PubMed Search using the search terms "partial nephrectomy, cooling," followed by a systematic and critical review was performed. CONCLUSION: Renal cooling during laparoscopic partial nephrectomy is a feasible, safe and effective procedure to expand ischemia time up to over 60 minutes, without risking significant and long lasting deterioration of renal function. It can be of value in patients with an imperative indication for partial nephrectomy, like solitary kidneys, synchronous bilateral tumors or renal failure in the opposite kidney as well as for patients at risk for deterioration of renal function and in any situation, where you think to yourself that 20 minutes will be maybe not enough to finish the job technically. Renal arterial perfusion provides the clinically best-studied option in this situation followed by ice-cold saline irrigation. Other surface coolants look promising, but still lack clinical data.

Focal cooling devices for the surgical treatment of epilepsy.

Focal cooling may provide a safe, nondestructive alternative to resective and disconnective strategies that have been proposed or used to control refractory epilepsy. Observations of the effects of direct application of iced saline on the cortical surface during cortical mapping surgery and induced seizures have led to interest in developing implantable cooling therapy devices for refractory localizable epilepsies. In this article, the authors provide an overview of the historical background, physiology, and animal and human data leading to the development of implantable cooling devices for the treatment of medically refractory epilepsy.

History of accidental hypothermia.

Death from exposure to cold has been recognised for thousands of years but hypothermia as a clinical condition was not generally recognised until the mid-20th century and then only in extreme conditions such as immersion in cold water or snow. In the UK, hypothermia in less extreme conditions was not generally recognised until the 1960s. Recognition of hypothermia required the temperature to be measured and this did not become a clinical tool until the late 1800s and it was not used routinely until the early 1900s. Although John Hunter and James Curry did some physiological experiments in the 1700s, detailed physiological experiments were not done until the early 20th century and the use of therapeutic hypothermia for malignancy and in anaesthesia in the 1930s and 1940s provided more impetus for investigating the physiology of hypothermia in humans and familiarising the medical profession with measuring core temperatures.

History and current trends in sudden cardiac arrest and resuscitation in adults.

Cardiac arrest occurs when organized cardiac contractility ceases and circulation stops. During cardiac arrest, electrical activity may be abnormal or absent, and the rhythm documented can be ventricular fibrillation, pulseless ventricular tachycardia, pulseless electrical activity, or asystole. It has been estimated that 300 000 sudden cardiac arrests occur each year in the United States, with 75% (225,000) occurring out-of-hospital and 25% (75,000) occurring in-hospital. A similar number occur in Europe each year. The 3-phase model of cardiac arrest, which proposes that a cardiac arrest progresses through distinct phases as time elapses, helps inform research and clinical care by providing a framework for improving outcomes from cardiac arrest. Early in an arrest, during the electrical phase, defibrillation is paramount. The circulatory phase begins after 4 to 5 minutes, and interventions to optimize circulation become of primary importance. When an arrest is prolonged, lasting for ≥10 minutes, the patient passes into the metabolic phase, in which significant metabolic derangements have accrued and start to dominate arrest physiology. If return of spontaneous circulation occurs during this phase, significant injury to diverse organs may have occurred, producing a critical illness known as post-cardiac arrest syndrome. The post-cardiac arrest syndrome has been recognized as a unique entity requiring unique therapies for successful management. Recent advances in cardiac arrest care include cardiocerebral resuscitation and the use of therapeutic hypothermia to treat comatose survivors of cardiac arrest.

Dominique-Jean Larrey: the effects of therapeutic hypothermia and the first ambulance.

The fields of emergency medicine and resuscitation are indebted to the Baron Dominique-Jean Larrey (1766-1842) for significant advances in patient care. Larrey was a great surgeon who served in the French army during Napoleon's rule. He developed one of the first ambulance services, utilized positive pressure ventilation, and introduced hypothermia as a form of therapy. He dedicated his professional life to improving the care of wounded soldiers on the battlefield. Larrey coined the term "Triage" to allocate resources to those most in need of emergent care. Today, many of his techniques still prevail in modern medicine.

Use of therapeutic hypothermia for term infants with hypoxic-ischemic encephalopathy.

Newborn encephalopathy represents a clinical syndrome with diverse causes, many of which may result in brain injury. Hypoxic-ischemic encephalopathy represents a subset of newborns with encephalopathy and, in contrast to other causes, may have a modifiable outcome. Laboratory research has demonstrated robust neuroprotection associated with reductions of brain temperature following hypoxia-ischemia in animals. The neuroprotective effects of hypothermia reflect antagonism of multiple cascades of events that contribute to brain injury. Clinical trials have translated laboratory observations into successful interventions. Hypoxicischemic encephalopathy is often unanticipated, unavoidable, and may occur in any obstetric setting. Pediatricians and other providers based in community hospitals play a critical role in the initial assessment, recognition, and stabilization of infants who may be candidates for therapeutic hypothermia.

Therapeutic hypothermia: the Safar vision.

At the 2(nd) International Brain Hypothermia conference, in Miami, the late Dr. Peter Safar was honored for his many contributions to the field of therapeutic hypothermia. Therapeutic hypothermia played a central role in his overall vision for optimized resuscitation and neurointensive care, across a large number of potential insults. The successful use of therapeutic hypothermia in comatose patients after cardiac arrest, for example, was already included in the historic first "ABCs" of resuscitation, published by Safar in 1964. This review addresses key historical events in the development and implementation of therapeutic hypothermia across a number of central nervous system insults. A discussion of future potential uses of this therapy in a variety of applications as part of the Safar vision is also presented.

Therapeutic hypothermia: applications in pediatric cardiac arrest.

There is a rich history for the use of therapeutic hypothermia after cardiac arrest in neonatology and pediatrics. Laboratory reports date back to 1824 in experimental perinatal asphyxia. Similarly, clinical reports in pediatric cold water drowning victims represented key initiating work in the field. The application of therapeutic hypothermia in pediatric drowning victims represented some of the seminal clinical use of this modality in modern neurointensive care. Uncontrolled application (too deep and too long) and unique facets of asphyxial cardiac arrest in children (a very difficult insult to affect any benefit) likely combined to result in abandonment of therapeutic hypothermia in the mid to late 1980s. Important studies in perinatal medicine have built upon the landmark clinical trials in adults, and are once again bringing therapeutic hypothermia into standard care for pediatrics. Although more work is needed, particularly in the use of mild therapeutic hypothermia in children, there is a strong possibility that this important therapy will ultimately have broad applications after cardiac arrest and central nervous system (CNS) insults in the pediatric arena.