Cardiac Arrest is a sudden stop of the pumping function of the heart, leading to cardiopulmonary standstill and if untreated to death.
Cerebral Performance Category (CPC) Scale
The Cerebral Performance Category (CPC) Scale is widely used in research and quality assurance to assess neurologic outcome following cardiac arrest. Scores are measured 3-6 months after discharge.
|1||Good cerebral performance||Conscious, alert, able to work, might have mild neurologic or psychologic deficits|
|2||Moderate cerebral disability||Conscious, independent activities of daily life, able to work in sheltered environment|
|3||Severe cerebral disability||Conscious with severe disability, ranges from ambulatory state to severe dementia or paralysis|
|4||Coma or vegetative state||Comatose or persistent vegetative state|
|5||Brain death||Brain dead or death from other causes|
“Good outcome” = CPC 1-2 “Poor outcome” = CPC 3-5
Critically-ill Neurological Patients
Critically-ill neurological patients are characterized by an immanent risk of severe and irreversible neurological injury or death. These patients suffer from diseases of the central nervous system such as ischemic or hemorrhagic stroke, severe traumatic brain injury, infections, metabolic encephalopathy, brain tumors etc.
It refers to a variety of cold applications in the treatment of pain and edema after acute soft tissue injury and after orthopaedic surgery (i.e. after arthroscopy, meniscectomy, ligament reconstruction). In addition, it helps to improve the mobility of joints, nerves and muscles.
Fever is not a primary illness but a symptom of illness.
Normothermic range of body temperature is 36.5–37.5°C. As a general standard for clinical practice a temporary increase in the body’s temperature to ≥38.3°C is considered febrile. Sub-febrile is an elevate temperature of up to 38.2°C, a temperature above 40°C is called hyperpyrexia.
Fever is caused by a fever inducing (pyrogenic) stimulus that elevates the thermostatic set-point of the brain. The cause can be either infectious or noninfectious.
Refractory (or intractable or resistant) fever is defined by e.g. no decrease in fever within 1-2 hours after administration of antipyretic drugs (650mg Paracetamol). No general definitions are available.
Central fever results from complex disturbances in or destruction of the thermoregulation center of the hypothalamus. For this reason, antipyretics are ineffective. It has high probability in patients with tumors or patients with subarachnoid / intracerebral hemorrhages and onset of fever within 72 hours of admission.
Glasgow Coma Scale (GCS)
The Glasgow Coma Scale is a simple neurologic scale for the assessment of impaired consciousness. It defines the level of consciousness on verbal, motor and eye-opening reactions to stimuli. It is the most commonly used system for classifying traumatic brain injury.
Heat Related Illnesses
Heat related illnesses are a spectrum of hyperthermic conditions caused by overheating of the body:
Lack of liquid and electrolytes is leading to intermittent muscle spasm.
Heat Exhaustion / Heat Collapse
Is caused by water and salt depletion, resulting in syncope (hypovolemic shock) and body temperatures up to 39.9°C.
Treatment of heat cramp and heat collapse include rest in supine position, rehydration and electrolyte substitution.
Heatstroke (sun stroke) can occur by overexertion in hot weather (exertional heat stroke, EHS) or in response to climatic extremes (non-exertional heat stroke, NEHS).
Heatstroke is characterized by a core temperature above 40°C, hot, dry skin and CNS abnormalities such as delirium, convulsions or coma. It is a potentially life-threatening emergency that includes a systematic inflammation. It may rapidly progress to a multi-organ dysfunction syndrome and has often fatal outcome.
The most important primary treatment (NAFES Guidelines 2014) is body temperature reduction to <39°C within 30 minutes. Therefore, patients should be cooled first, then being transported.
A hematoma is usually caused by trauma and describes a collection of blood outside a blood vessel. Hematomas inside the skull increase the pressure and potentially impair the ability of the brain function.
The term is used to describe active bleeding (the blood hasn’t yet clotted).
Intracerebral Hemorrhage (ICH)
Caused by arteries which burst within the brain itself.
Subarachnoid Hemorrhage (SAH), Epidural (EDH) / Subdural (SDH) Hematoma
Burst of arteries between/below the membranes of the brain is resulting in bleeding at the surface of the brain.
Hyperthermia (e.g. heatstroke) describes an increase in body temperature above the body’s thermostatic set point of about 36.5-37.5°C. It can result from increased ambient temperatures, excessive metabolic heat production (e.g. by overexertion, a thyroid storm, a pharmacological stimulus) or decreased heat dissipation (e.g. in humid environment, poor sweat production).
Intracranial Pressure (ICP), Intracranial Hypertension
An elevated ICP is mainly caused by cerebral edema or hematoma. Its classical manifestation is the cushing triad: slow heart rate, high blood pressure and respiratory depression symptoms like i.e. vomiting, seizures, mental confusion, paralysis, fainting, coma or cardio-pulmonary arrest.
|ICP thresholds||ICP values [mmHg]|
(à start of therapy)
Ischemia is a restriction in blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism. Treatment is directed towards increasing circulation to the affected body area.
Local (focal) Ischemia
Inadequate local blood supply due to a blockage of blood vessels e.g. in ischemic stroke.
Inadequate blood supply of the whole body due to a standstill of the blood circulation i.e. in cardiac arrest.
Myocardial Infarction, Acute (AMI)
AMI is usually caused by a blockage in a coronary artery. This leads to necrosis of myocardial tissue in the less/no perfused area (infarction area). Therapy in patients with an on-going ST-elevation myocardial infarction (STEMI) is to re-perfuse the ischemic myocardium as soon as possible. Reperfusion by itself causes additional damage of myocardial tissue (post-ischemic reperfusion injury) and may be reduced by therapeutic hypothermia <35°C.
Neuro Intensive Care Unit (NICU)
Main purpose of neuro-intensive care is to prevent secondary brain injury. NICU provides continuous monitoring of post-operative neurosurgical patients as well as patients with primary head trauma, severe, acute strokes, intracranial hemorrhages, elevated ICP and unstable pulmonary or cardiovascular conditions.
Normothermia / Fever Treatment
Reduction of hyperthermic body temperatures and maintaining a normothermic range of core body temperature (36.5-37.5°C). Treatment is indicated e.g. in patients with high fever magnitude, septic shock or severe hemodynamic instability and in febrile patients with neurologic injuries. Fever occurs in 20-50% of critically-ill neurological patients and even small temperature elevations are correlated with increased morbidity and mortality.
Antipyretic medication like Paracetamol, Ibuprofen or Metamizol act by promoting the return of the elevated thermostatic set-point to a normal range of body temperature.
External/physical cooling methods accelerate the heat dissipation through the skin by conduction (e.g. ice bags/packs, cooling blankets), convection (e.g. fanning) or evaporation (e.g. wet clothes plus fanning, calf compressions).
Post Cardiac Arrest Syndrome
This syndrome includes all clinical and biological manifestations related to global ischemia reperfusion that occur after cardiac arrest and return of spontaneous circulation. The main component is an early, but severe cardio-circulatory dysfunction that may lead to multiple organ failure and death. This state is often complicated by the unresolved pathological process that caused the cardiac arrest.
Reperfusion injury is the tissue damage when blood supply (reperfusion) returns to the tissue after a period of ischemia or lack of oxygen. A temporary lack of oxygen and nutrients is associated with inflammation and oxidative damages after reperfusion and may be reduced by cooling.
Return of Spontaneous Circulation (ROSC)
ROSC is the restoration of sustained cardiovascular circulation after cardiac arrest. Signs of ROSC include breathing, coughing or movement and a palpable pulse / measurable blood pressure.
Cardiopulmonary resuscitation (CPR) and defibrillation (external AED) increase the chances of ROSC.
Attenuation of the central nervous system due to sedative or tranquilizing medication (e.g. benzodiazepine). The boundaries between sedation and anesthesia (narcosis) are floating.
Simultaneous administration of sedative and analgetic (pain) medication
Narcotic analgesia: Opioids e.g. Morphine, Fentanyl, Meperidine
Sedative medication: Benzodiazepine (e.g. Midazolam), receptor agonists (e.g. Buspiron, Propofol)
Substances that are used e.g. for intra-operative anesthesia and during therapeutic hypothermia. Their effect reaches from a temporary relaxation to total paralysis of the overall musculature (including the breathing muscles). Totally paralyzed patients are intubated and mechanically ventilated.
Muscle relaxants (paralytic agents) are e.g. Pancuronium, Atacurium, Vecuronium.
Sepsis constitutes a continuous spectrum of diseases, which can worsen rapidly and may result in a septic shock.
Penetration of pathogens into the bloodstream, followed by a systemic inflammation (SIRS = systemic inflammatory response syndrome).
Sepsis in conjunction with limited function of at least one organ (e.g. brain, kidneys, lever, intestine).
Severe sepsis in conjunction with a life-threatening drop in blood pressure and cardiovascular disorders, causing cell death in tissue and organs and may lead to multi-organ dysfunction.
Shivering / Anti-shivering Medication
Thermoregulatory mechanism to compensate heat losses by spontaneous muscle activity. Shivering is starting at core body temperatures of around 35.5°C and is associated with high increases of metabolic rate and oxygen consumption. Shivering counteracts the efficiency of physical cooling methods. It needs to be suppressed in fever therapy and during therapeutic hypothermia by various combinations of anti-shivering medication.
Soft Tissue Injury
Damage of soft tissue (like muscles, ligaments, tendons, fat, myofascial tissue, joint capsules, skin). It may occur from sprain, strain, contusion (bruise) or overuse of a particular part of the body. Soft tissue injuries result in pain, swelling, bruising and loss of function.
Stroke (Brain Attack, Cerebrovascular Accident = CVA)
Stroke is an impaired circulation in a localized area in the brain, causing neurological dysfunction and subsequently leading to sudden death of brain cells (infarction) in the non-perfused area. The hypo-perfused zone (penumbra) around the infarction area can be salvaged, if reperfusion takes place rapidly e.g. after rapid thrombolysis. As with many ischemic conditions cooling might improve the neurologic outcome as the penumbra area is protected.
Ischemic strokes (80-90% of strokes) occur when a blood vessel becomes occluded. Restoration of blood supply to the affected part of the brain is indicated by clot-busting drugs (thrombolytic) within a 3 to 4.5 hours window to use or by mechanical removal of the clot (thrombectomy).
10-20% of strokes (but 40 percent of all stroke deaths), either caused by a brain aneurysm burst or a weakened blood vessel leak. Bleeding into or around the brain creates swelling and pressure, vascular disorders and destruction of nervous tissue. There are two types of hemorrhagic stroke called intracerebral and subarachnoid. The treatment includes surgical removal or endovascular “plugging” of the ruptured vessel.
Targeted Temperature Management (TTM) / Temperature Control
TTM is any active therapy to achieve and maintain a specific target temperature for a defined duration (ILCOR Advisory Statement 2015).
Therapeutic Hypothermia (TH)
TH is defined as an active cooling therapy to lower a normal body temperature to a target temperature in the range of 32-36°C (including the classical temperature range 32-34°C). Aim of the therapy is to reduce/prevent post-ischemic reperfusion injury after local or global ischemic events in numerous diseases.
Note: The updated Resuscitation Guidelines (ERC / AHA 2015) state that TTM or temperature control is now preferred over the previous term TH. In daily practice, both terms will be used.
Normothermia Treatment (NT)
NT is defined as reducing hyperthermic body temperatures and maintaining a normothermic range of core body temperature (36.5-37.5°C). NT is indicated e.g. in patients with high fever magnitude, septic shock or severe hemodynamic instability and in febrile patients with neurologic injuries. Fever occurs in 20-50% of critically-ill neurological patients and even small temperature elevations are correlated with increased morbidity and mortality.
Traumatic Brain Injury (TBI)
TBI occurs if an outside impact causes damage to the brain. The symptoms can be mild, moderate or severe, ranging from comparatively harmless concussions to life-threatening compressions.
= 1st grade
short loss of brain function without irreversible damage
= 2nd grade
hematoma, bleeding, edema, elevated ICP, crushing of tissue
= 3rd grade
tearing of tissue, herniation due to hematoma or edema, elevated ICP, pressure on vital organs
GCS = Glasgow Coma Scale
Primary Brain Injury
Irreversible damage, which occurs at the moment of trauma. Tissue and blood vessels are stretched, compressed and/or burst (closed or penetrating trauma).
Secondary Brain Injury
Destructive processes that take place minutes to days after trauma, resulting in e.g. nerve cell death, changes in cerebral blood flow and intracranial pressure. The final outcome is substantially dependent by secondary brain injury.
Traumatic Brain Injury, Severe
Characterized by an initial Glasgow Coma Scale (GCS) ≤8, impairment of consciousness >24 hours and/or partial reduced function of the brain stem (i.e. respiratory arrest, difficulties to swallow).