A history of resuscitation

Targeted Temperature Management in Cardiac Arrest: An Updated Narrative Review

The established benefits of cooling along with development of sophisticated methods to safely and precisely induce, maintain, monitor, and reverse hypothermia have led to the development of targeted temperature management (TTM). Early trials in human subjects showed that hypothermia conferred better neurological outcomes when compared to normothermia among survivors of cardiac arrest, leading to guidelines recommending targeted hypothermia in this patient population. Multiple studies have sought to explore and compare the benefit of hypothermia in various subgroups of patients, such as survivors of out-of-hospital cardiac arrest versus in-hospital cardiac arrest, and survivors of an initial shockable versus non-shockable rhythm. Larger and more recent trials have shown no statistically significant difference in neurological outcomes between patients with targeted hypothermia and targeted normothermia; further, aggressive cooling is associated with a higher incidence of multiple systemic complications. Based on this data, temporal trends have leaned towards using a lenient temperature target in more recent times. Current guidelines recommend selecting and maintaining a constant target temperature between 32 and 36 °C for those patients in whom TTM is used (strong recommendation, moderate-quality evidence), as soon as possible after return of spontaneous circulation is achieved and airway, breathing (including mechanical ventilation), and circulation are stabilized. The comparative benefit of lower (32-34 °C) versus higher (36 °C) temperatures remains unknown, and further research may help elucidate this. Any survivor of cardiac arrest who is comatose (defined as unarousable unresponsiveness to external stimuli) should be considered as a candidate for TTM regardless of the initial presenting rhythm, and the decision to opt for targeted hypothermia versus targeted normothermia should be made on a case-by-case basis.

Reported Resuscitation of a Hypothermic Avalanche Victim With Assisted Ventilation in 1939

We present a historical case of a 12-year-old boy who survived a reported avalanche burial in 1939 in the Upper Peninsula of Michigan. The boy was completely buried for at least 3 h, head down, at a depth of about 1 m. He was extricated without signs of life and likely hypothermic by his father, who took him to his home. There, the father performed assisted ventilation for 3 hours using the Schäfer method, a historical method of artificial ventilation, without any specific rewarming efforts. The boy recovered neurologically intact. This case illustrates the importance of attempting resuscitation, possibly prolonged, of victims of hypothermia, even those who are apparently dead.

Variability in the time to initiation of CPR in continuously monitored pediatric ICUs

AIM

To study the influence of patient characteristics and unit ergonomics and human factors on the time to initiation of CPR.

METHODS

A single center study of children, 0 to 21 years old, admitted to an ICU who experienced cardiopulmonary arrest (CPA) requiring >1 min of chest compressions. Time of CPA was determined by analysis of continuous ECG, plethysmography, arterial blood pressure, and end-tidal CO₂ (EtCO₂) waveforms. Initiation of CPR was identified by the onset of cyclic artifact in the ECG waveform. Patient characteristics and unit ergonomics and human factors were examined including CPA cause, identification on the High-Risk Checklist (HRC), existing monitoring, ICU type, time of day, nursing shift change, and outcome.

RESULTS

The median time from CPA to initiation of CPR was 50.5 s (IQR 26.5 to 127.5) in 36 CPAs. Forty-seven percent of patients experienced time from CPA to initiation of CPR of >1 min. There was no difference in CPA cause, ICU type, time of day, or nursing shift change.

CONCLUSION

Nearly half of pediatric patients who experienced CPA in an ICU setting did not meet AHA guidelines for early initiation of CPR. This is an opportunity to study the recognition phase of CPA using continuous monitoring data with the aim of improving the understanding of and factors contributing to delays in initiation of CPR.

Irrational Exuberance: Cardiopulmonary Resuscitation as Fetish

The Institute of Medicine and the American Heart Association have issued a "call to action" to expand the performance of cardiopulmonary resuscitation (CPR) in response to out-of-hospital cardiac arrest. Widespread advertising campaigns have been created to encourage more members of the lay public to undergo training in the technique of closed-chest compression-only CPR, based upon extolling the virtues of rapid initiation of resuscitation, untempered by information about the often distressing outcomes, and hailing the "improved" results when nonprofessional bystanders are involved. We describe this misrepresentation of CPR as a highly effective treatment as the fetishization of this valuable, but often inappropriately used, therapy. We propose that the medical profession has an ethical duty to inform the public through education campaigns about the procedure's limitations in the out-of-hospital setting and the narrow clinical indications for which it has been demonstrated to have a reasonable probability of producing favorable outcomes.

The art of providing resuscitation in Greek mythology

BACKGROUND

We reviewed Greek mythology to accumulate tales of resuscitation and we explored whether these tales could be viewed as indirect evidence that ancient Greeks considered resuscitation strategies similar to those currently used.

METHODS

Three compendia of Greek mythology: The Routledge Handbook of Greek Mythology, The Greek Myths by Robert Graves, and Greek Mythology by Ioannis Kakridis were used to find potentially relevant narratives.

RESULTS

Thirteen myths that may suggest resuscitation (including 1 case of autoresuscitation) were identified. Methods to attempt mythological resuscitation included use of hands (which may correlate with basic life support procedures), a kiss on the mouth (similar to mouth-to-mouth resuscitation), application of burning torches (which might recall contemporary use of external defibrillators), and administration of drugs (a possible analogy to advanced life support procedures). A careful assessment of relevant myths demonstrated that interpretations other than medical might be more credible.

CONCLUSIONS

Although several narratives of Greek mythology might suggest modern resuscitation techniques, they do not clearly indicate that ancient Greeks presaged scientific methods of resuscitation. Nevertheless, these elegant tales reflect humankind's optimism that a dying human might be restored to life if the appropriate procedures were implemented. Without this optimism, scientific improvement in the field of resuscitation might not have been achieved.

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.

The small chill: mild hypothermia for cardioprotection?

Reducing the heart's temperature by 2-5°C is a potent cardioprotective treatment in animal models of coronary artery occlusion. The anti-infarct benefit depends upon the target temperature and the time at which cooling is instituted. Protection primarily results from cooling during the ischaemic period, whereas cooling during reperfusion or beyond offers little protection. In animal studies, protection is proportional to both the depth and duration of cooling. An optimal cooling protocol must appreciably shorten the normothermic ischaemic time to effectively salvage myocardium. Patients presenting with acute myocardial infarction could be candidates for mild hypothermia since the current door-to-balloon time is typically 90 min. But they would have to be cooled quickly shortly after their arrival. Several strategies have been proposed for ultra-fast cooling, but most like liquid ventilation and pericardial perfusion are too invasive. More feasible strategies might include cutaneous cooling, peritoneal lavage with cold solutions, and endovascular cooling with intravenous thermodes. This last option has been investigated clinically, but the results have been disappointing possibly because the devices lacked capacity to cool the patient quickly or cooling was not implemented soon enough. The mechanism of hypothermia's protection has been assumed to be energy conservation. However, whereas deep hypothermia clearly preserves ATP, mild hypothermia has only a modest effect on ATP depletion during ischaemia. Some evidence suggests that intracellular signalling pathways might be responsible for the protection. It is unknown how cooling could trigger these pathways, but, if true, then it might be possible to duplicate cooling's protection pharmacologically.

Therapeutic hypothermia: implications for acute care practitioners

The use of therapeutic hypothermia (TH) in acute care medicine has evolved over the past 2 centuries, and its use over the past decade has increased in emergency departments, intensive care units, and operating rooms. Therapeutic hypothermia has several potential clinical applications based on its putative mechanisms of action. It appears to improve oxygen supply to ischemic areas of the brain and decreases intracranial pressure. Mild-to-moderate TH (33 degrees C +/- 1 degrees C) after resuscitation from cardiac arrest is neuroprotective, and also acts on the cardiovascular system with evidence of a decrease in heart rate and increase in systemic vascular resistance. Therapeutic hypothermia decreases cardiac output by 7% for each 1 degrees C decrease in core body temperature, but maintains the stroke volume and the mean arterial pressure. Despite a growing amount of data, this life-saving technique is underutilized in hospitals worldwide. The purpose of this comprehensive review is to show the evolution and the clinical use of TH as it pertains to acute care practitioners.

Therapeutic hypothermia: past, present, and future

Cardiac arrest causes devastating neurologic morbidity and mortality. The preservation of the brain function is the final goal of resuscitation. Therapeutic hypothermia (TH) has been considered as an effective method for reducing ischemic injury of the brain. The therapeutic use of hypothermia has been utilized for millennia, and over the last 50 years has been routinely employed in the operating room. TH gained recognition in the past 6 years as a neuroprotective agent in victims of cardiac arrest after two large, randomized, prospective clinical trials demonstrated its benefits in the postresuscitation setting. Extensive research has been done at the cellular and molecular levels and in animal models. There are a number of proposed applications of TH, including traumatic brain injury, acute encephalitis, stroke, neonatal hypoxemia, and near-drowning, among others. Several devices are being designed with the purpose of decreasing temperature at a fast and steady rate, and trying to avoid potential complications. This article reviews the historical development of TH, and its current indications, methods of induction, and potential future.

Elements of the medical emergency's epistemological alignment: 18-20th-century perspectives

This paper develops the concept of epistemological alignment as a means of understanding how the medical emergency entered into biomedical classification. The working hypothesis is that the medical emergency could not develop as a paradigm from which knowledge could proliferate until a series of related concepts has been elucidates, and its epistemology became aligned. This argument is advanced by exploring the historically constructed lexicon of the medical emergency's key components. In the process, a semantic network created by 18th-century attempts to problematize sudden death is elucidates and explored. The paper concludes by arguing that the First World War served as a catalyst for the alignment of concepts central to the epistemology of the medical emergency.

Resuscitation in the hospital: relationship of year and rhythm to outcome

OBJECTIVE

determine the frequency of initial rhythms in in-hospital resuscitation and examine its relationship to survival. Assess changes in outcome over time.

METHODS

retrospective cohort (registry) including all admissions to the Medical Center of Central Georgia in which a resuscitation was attempted between 1 January, 1987 and 31 December, 1996.

RESULTS

the registry includes 3327 admissions in which 3926 resuscitations were attempted. Only the first event is reported. There were 961 hospital survivors. Survival increased from 24.2% in 1987 to 33.4% in 1996 (chi(2)=39.0, df=1, P<0.0001). Survival was affected strongly by initial rhythm (chi(2)=420.0, df=1, P<0.0001) and decreased from 63.2% for supraventricular tachycardia (SVT) to 55.3% for ventricular tachycardia (VT), 51.0% for perfusing rhythms (PER), 34.8% for ventricular fibrillation (VF), 14.3% for pulseless electrical activity (PEA) and 10.0% for asystole (ASYS). PEA was the most frequent rhythm (1180 cases) followed by perfusing (963), asystole (580), VF (459), VT (94) and SVT (38).

DISCUSSION

the powerful effect of initial rhythm on survival has been reported in pre-hospital and in-hospital resuscitation. VF is considered the dominant rhythm and generally accounts for the most survivors. We report good outcome for each; however, VF represents only 13.8% of events and 16.7% of survivors. PEA accounts for more survivors (169) than does VF (160). Our improved outcome is partially explained by changes in rhythms, but other institutional variables need to be identified to fully explain the results. Further studies are needed to see if our findings can be sustained or replicated.

Cardiopulmonary resuscitation: a review for clinicians

Attempts at cardiopulmonary resuscitation (CPR) date from antiquity, but it is only in the last 50 years that a scientifically-based methodology has been developed. External chest compressions is the standard method for managing circulatory arrest, however, numerous alterations of this technique have been proposed in attempts to improve outcome from CPR. Defibrillation is the single most important therapy for the management of ventricular fibrillation or pulseless ventricular tachycardia. Adrenergic agents used to improve myocardial and cerebral perfusion are also the subject of considerable investigation with new agents entering clinical study. This paper reviews the history, current techniques and pharmacotherapy as well as controversial issues in the management of patients with cardiac arrest.

Cardiopulmonary resuscitation. New and controversial techniques

Primary care physicians may need to perform cardiopulmonary resuscitation (CPR) from time to time. Knowledge regarding CPR has become extensive, and it is hoped that greater success will be achieved in the future with the advent of new methods. A number of techniques and devices have received attention in the lay and professional press. If appropriate care is to be delivered, practicing physicians must be aware of what is proven technology and what is investigational.

Cardiopulmonary resuscitation: lessons from the past

One of the most startling ideas of modern medicine is that "sudden death" may be reversed; however, this idea was not reached easily. In its earliest forms, cardiopulmonary resuscitation (CPR) is probably as old as the human being. The evolution of CPR represents, as does the evolution of medicine as a whole, a history of human error and human discovery. Although it is common to ascribe the development of CPR to Kouwenhoven and colleagues at Johns Hopkins Hospital, in fact they refined and popularized a method that had been evolving over several millennia. This paper reviews the most important advances in resuscitation prior to the 20th century.

Pharmacotherapy of circulatory shock

The rubric "shock" encompasses a wide spectrum of critical events, which if untreated, result in morbidity and mortality. Understanding of the various forms of shock has evolved rapidly in the past 20 years as new laboratory and clinical observations have been published. In this article, the authors discuss the physiology of the shock state, review the circumstances in which shock becomes likely, and review the etiologies and diagnostic characteristics of distributive (septic, spinal, anaphylactoid/anaphylactic), cardiogenic, hypovolemic, and obstructive shock. The rationale and applications of conventional and controversial therapies are discussed. The therapeutic potentials of current lines of shock research are also discussed.