Methods of cooling: practical aspects of therapeutic temperature management. Crit Care Med. 2009;37:S211-S222. [PMID: 19535949 DOI: 10.1097/ccm.0b013e3181aa5bad]

Therapeutic hypothermia for adult viral meningoencephalitis

BACKGROUND

Despite the advances in critical care, severe viral meningoencephalitis continues to impose high rates of morbidity and mortality. Consequently, new treatment strategies are needed and we present therapeutic hypothermia (TH) as one of the possible efficacious treatment tools.

METHODS

We present the case series in an adult intensive care unit of a tertiary care hospital. Eleven patients suffering from severe viral meningoencephalitis were treated with hypothermia. The major indication for TH was severely impaired consciousness associated with carbon dioxide reactivity loss assessed by Transcranial Doppler. Besides from the established treatment, all the patients underwent TH. Mild hypothermia (rectal temperature of 32-34°C) was maintained with continuous veno-venous hemofiltration.

RESULTS

Median Glasgow coma scale score in our patients at admission was 8 (3-10) and median Acute Physiology and Chronic Health Evaluation score was 24 (12-32). The overall mortality rate was 9% (1/11). Among survivors, the outcome was favorable in five patients [Glasgow Outcome Scale score (GOS) 4-5]. Remaining five patients had severe residual neurological deficit (GOS 3). Median GCS at discharge was 15 (8-15). With respect to disease severity, the outcome in presented patients was generally satisfactory.

CONCLUSIONS

Our results suggest that use of mild hypothermia in selected adult patients with viral meningoencephalitis could be a promising treatment tool.

A comparison of intravascular and surface cooling techniques in comatose cardiac arrest survivors

OBJECTIVES

Mild therapeutic hypothermia after out-of-hospital cardiac arrest is usually achieved either by surface cooling or by core cooling via the patient's bloodstream. We compared modern core (Coolgard) and surface (Arctic Sun) cooling devices with a zero hypothesis of equal cooling, complications, and neurologic outcomes.

DESIGN

Single-center observational study.

SETTING

University hospital medical and cardiac intensive care units.

PATIENTS

One hundred sixty-seven consecutive patients comatose after out-of-hospital cardiac arrest of all causes treated with mild therapeutic hypothermia in a 5-yr period.

INTERVENTIONS

Nonrandomized allocation to core or surface cooling depending on availability and physician preference.

MEASUREMENTS AND MAIN RESULTS

All out-of-hospital cardiac arrest patients' records were reviewed for relevant data regarding medical history, cardiac arrest event, prehospital care, in-hospital treatment, and complications. Survivor neurologic function was reassessed at follow-up after 6 to 12 months. Baseline patient and arrest episode characteristics were similar in the treatment groups. There was no significant difference in survival with good neurologic function, either to hospital discharge (surface, 34/90, 38%; core, 34/75, 45%; p=.345) or at follow-up (surface, 34/88, 39%; core, 34/75, 45%; p=.387). Time from cardiac arrest to achieving mild therapeutic hypothermia was equal with both devices (surface, 273 min, interquartile range 158-330; core, 270 min, interquartile range 190-360; p=.479). There were significantly more episodes of sustained hyperglycemia among the surface-cooled patients (surface, 64/92, 70%; core, 36/75, 48%; p=.005) and significantly more hypomagnesaemia among core-cooled patients (surface, 16/87, 18%; core, 27/74, 37%; p=.01).

CONCLUSIONS

In this study, surface and core cooling of out-of-hospital cardiac arrest patients following the same established postresuscitation treatment protocol resulted in similar survival to hospital discharge and comparable neurologic function at follow-up.

Therapeutic hypothermia

Pioneer works on therapeutic hypothermia (TH) half a century ago already showed promising results but clinical application was limited by a lack of understanding of the underlying pathophysiology, lack of reliable method for temperature control and lack of intensive care facilities to deal with possible complications. More recently, 2 studies in 2002 supported the application of moderate TH (32.0-34.0℃) in post-cardiac arrest patients. Although the studies included only patients suffering from out-of-hospital VF, many ICUs world-wide are applying the therapy to all post-cardiac arrest patients irrespective of site or presenting rhythm. While primary coagulopathy and cardiogenic shock are usually stated as relative contraindications, evidences are accumulating to support the application of TH in patients with cardiogenic shock. TH can be divided into 4 phases: Induction, maintenance, de-cooling and normothermia. Induction is usually achieved by infusion of cold isotonic fluid. The precautions included avoidance of over-cooling, hypokalaemia, hyperglycaemia, and shivering. TH can be maintained by many different methods, varying in their level of invasiveness, cost and effectiveness. Issues including changes in pharmacokinetics and haemodynamics, and susceptibility to infection need to the addressed. The optimal duration of maintenance is unknown but the usual practice is 12-24 hours. De-cooling and rewarming is especially challenging because complications can be serious if temperature rise by more than 1℃ every 3-5 hours. Life-theatening hyperkalaemia can occur especially if patient suffers from renal insufficiency. Fever is a frequent complication either due to infection or post-cardiac arrest syndrome but patient must be kept normothermic for 72 hours.

Postresuscitation care: entering a new era

PURPOSE OF REVIEW

The purpose of this study is to discuss recent data relating to the treatment of cardiac arrest survivors. This is a rapidly evolving component of resuscitation medicine that impacts significantly on the quality of survival after cardiac arrest.

RECENT FINDINGS

The postcardiac arrest syndrome comprises postcardiac arrest brain injury, postcardiac arrest myocardial dysfunction, the systemic ischaemia/reperfusion response, and the persistent precipitating disease. Primary percutaneous coronary intervention is the preferred method for restoring coronary perfusion when cardiac arrest has been caused by an ST-elevation myocardial infarction. Many cardiac arrest survivors with non-ST-elevation myocardial infarction may also benefit from urgent percutaneous coronary intervention. Comatose cardiac arrest survivors should be managed with a moderate blood glucose target range of below 10 mmol/l (180 mg/dl). Therapeutic hypothermia is now generally accepted as part of a treatment strategy for comatose survivors of cardiac arrest, but its use may render conventional methods of prognostication unreliable.

SUMMARY

Survivors from cardiac arrest develop a postcardiac arrest syndrome. Postresuscitation care, including primary percutaneous coronary intervention, therapeutic hypothermia, and control of blood sugar, improves survival and neurological outcome in cardiac arrest survivors. Completely reliable prognostication in comatose survivors of cardiac arrest is difficult to achieve.

Therapeutic hypothermia: a case study

Approximately 300,000 people experience sudden cardiac arrest (SCA) per year. The percentage of people who survive to discharge from the hospital is a dismal 10% to 25%. After SCA and the administration of cardiopulmonary resuscitation, these individuals can suffer what is known as "post resuscitation syndrome." This syndrome includes post-cardiac arrest brain injury, a cycle of cerebral edema and cell death that can lead to permanent neurological damage. In two landmark studies, therapeutic hypothermia (TH) was found to improve the chances of being discharged from the hospital post SCA by significant percentages. Despite endorsements, from the American Heart Association and other professional organizations, TH is not a well-known intervention. There are many reasons why this may be true. Despite its proven usefulness, TH does have some side effects that are best handled in the setting of intensive care units. This article describes a case of therapeutic hypothermia and its implications for perianesthesia nursing care.