Use of hypothermia in the intensive care unit

Abstract

Used for over 3600 years, hypothermia, or targeted temperature management (TTM), remains an ill defined medical therapy. Currently, the strongest evidence for TTM in adults are for out-of-hospital ventricular tachycardia/ventricular fibrillation cardiac arrest, intracerebral pressure control, and normothermia in the neurocritical care population. Even in these disease processes, a number of questions exist. Data on disease specific therapeutic markers, therapeutic depth and duration, and prognostication are limited. Despite ample experimental data, clinical evidence for stroke, refractory status epilepticus, hepatic encephalopathy, and intensive care unit is only at the safety and proof-of-concept stage. This review explores the deleterious nature of fever, the theoretical role of TTM in the critically ill, and summarizes the clinical evidence for TTM in adults.

Keywords: Cardiac arrest; Critical care; Intracerebral pressure; Normothermia; Targeted temperature management; Therapeutic hypothermia.

Figures

Figure 1

Schematic of fever production. POAH: Pre-optic area of the anterior hypothalamus; IL: Interleukin; TNF: Tumor necrosis factor; INF: Interferon; WBC: White blood cell; PGE2: Prostaglandin E2; NE: Norepinephrine.

Figure 2

Metabolic pattern of common neurocritical care unit disease. CBF: Cerebral blood flow; TBI: Traumatic brain injury; ICH: Intracerebral hemorrhage.

Figure 3

Approximate percent increases in cerebral edema, over time, in stroke and intensive care unit patients treated with and without targeted temperature management. Changes between stroke patients effectively and ineffectively cooled, and changes between intensive care unit patients receiving targeted temperature management (TTM) and controls not receiving TTM, are significant. Stroke patients day two measurements are between 36-48 h. ICH: Intracerebral hemorrhage.