A hypothermia cap (also referred to as cold cap or cooling cap) is a therapeutic device used to cool the human scalp. Its most prominent medical applications are in preventing or reducing
alopecia
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarri ...
in
chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
, and for preventing
cerebral palsy
Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, stiff muscles, weak muscles, and tremors. There may be problems with sensa ...
in babies born with
neonatal encephalopathy caused by hypoxic-ischemic encephalopathy (HIE). It can also be used to provide
neuroprotection
Neuroprotection refers to the relative preservation of neuronal structure and/or function. In the case of an ongoing insult (a neurodegenerative insult) the relative preservation of neuronal integrity implies a reduction in the rate of neuronal los ...
after
cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
, to inhibit
stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
paralysis, and as
cryotherapy
Cryotherapy, sometimes known as cold therapy, is the local or general use of low temperatures in medical therapy. Cryotherapy may be used to treat a variety of tissue lesions. The most prominent use of the term refers to the surgical treatment, s ...
for
migraine headaches
Migraine (, ) is a common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few ho ...
.
Worn tight on the head, hypothermia caps are typically made of a synthetic such as
neoprene
Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion R ...
,
silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking ...
or
polyurethane
Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan ...
, and filled with a
coolant
A coolant is a substance, typically liquid, that is used to reduce or regulate the temperature of a system. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, chemically inert and neither causes nor promotes corrosio ...
agent such as ice or gel which is either frozen to a very cold temperature (−25 °C to −30 °C, or −13 °F to −22 °F) before application or continuously cooled by an auxiliary control unit.
In the United States a course of treatment may cost 1,500 to 3,000.
Medical uses
Neonatal encephalopathy
Hypoxic ischemic encephalopathy
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in o ...
(HIE) is a condition that occurs when the brain is deprived of an adequate oxygen supply, and is most commonly observed in newborn babies due to
birth asphyxia
Perinatal asphyxia (also known as neonatal asphyxia or birth asphyxia) is the medical condition resulting from deprivation of oxygen to a newborn infant that lasts long enough during the birth process to cause physical harm, usually to the brain. ...
. It is the leading cause of
cerebral palsy
Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, stiff muscles, weak muscles, and tremors. There may be problems with sensa ...
, an irreversible neonatal brain injury that can result in long-term cognitive, motor, and visual impairments. About 10,000 babies are born each year with cerebral palsy.
In such cases, by slowing down cell metabolism and body functions, a hypothermic cap can be used to lessen a baby's need for oxygen. Research throughout the late 1990s and 2000s demonstrated that for every degree a baby's body temperature is lowered, its body functions and demand for energy slow down by 10 to 15 percent. Therefore, slowing metabolic demands through
hypothermia therapy can rectify a mismatch between oxygen supply and cell need, lowering the risk for cerebral palsy.
Among babies who meet the criteria for hypothermia therapy—full-term with no known pre-existing conditions, having neonatal distress, and an abnormal neurological exam
—cooling must begin within six hours of birth and body temperature must be maintained at 33–34 °C (91–93 °F) for 72 hours before being gradually warmed again. An alternative to hypothermia caps involves pumping cold water through a specially adapted blanket, cooling the whole body.
Induced pediatric hypothermia was approved in the U.S. by the FDA in March 2007. The most prominent such hypothermia cap which utilizes a cooling unit, a control unit and temperature probes to maintain a steady flow of cool water through a cap covering the head.
Cardiac arrest
A 2008 trial demonstrated that the pre-hospital induction of
therapeutic hypothermia
Targeted temperature management (TTM) previously known as therapeutic hypothermia or protective hypothermia is an active treatment that tries to achieve and maintain a specific body temperature in a person for a specific duration of time in an e ...
after cardiac arrest as soon as possible after
return of spontaneous circulation Return of spontaneous circulation (ROSC) is the resumption of a sustained heart rhythm that perfuses the body after cardiac arrest. It is commonly associated with significant respiratory effort. Signs of return of spontaneous circulation include bre ...
(ROSC) can achieve optimal neuroprotective benefit. The hypothermia cap was applied to 20 patients after out-of-hospital cardiac arrest, with a median of 10 min after ROSC. The median time between initiation of cooling and hospital admission was 28 minutes. No side effects related to the hypothermia cap were observed. The study concluded that "prehospital use of hypothermia caps is a safe and effective procedure to start therapeutic hypothermia after cardiac arrest. This approach is rapidly available, inexpensive, non-invasive, easy to learn and applicable in almost any situation."
Chemotherapy-induced hair loss
Hypothermia caps appear useful to prevent
hair loss
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarri ...
during some kinds of
chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
, specifically when
taxanes
Taxanes are a class of diterpenes. They were originally identified from plants of the genus ''Taxus'' (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents. Cabazitaxel was FDA ap ...
or
anthracyclines
Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from ''Streptomyces'' bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder cance ...
are used.
It should not be used when cancer is present in the skin of the scalp or in people with
lymphoma
Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlar ...
or
leukemia
Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ' ...
. There are generally only minor side effects from treatment.
The first U.S. patent, filed in 1979 and granted in 1984, was for
Mark Barron's "Chemo Cap", which consisted of resizable gel-filled nylon pouches that were frozen and worn for 15 to 20 minutes prior to treatment. However, studies throughout the 1980s and early 1990s were not sufficiently encouraging,
and the patent expired in 1998. An analysis of 53 studies from 1995 through 2003, however, showed an average success rate of 73%.
Today there are two types of caps; Manual cold caps sometimes referred to as 'Cold Caps/Cold Capping' & machine cooling often referred to as 'Scalp Cooling' However they can be used interchangeably.
There are three major providers of scalp cooling
Penguin Cold CapPaxmanDignitana
Other uses
The use of hypothermia caps has also shown promise in inhibiting
stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
paralysis
Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...
. Studies are underway testing a combination treatment consisting of four drugs plus a hypothermia cap to try to slow the cell death that is triggered by an
ischemic stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
.
[Ruttan, Susan (January 27, 2006)]
"Icy head may reduce stroke"
''The Windsor Star''. p. D10 Ischemic strokes are caused when a clot blocks blood flow to the brain, and comprise roughly 80% of all strokes.
The slowing of cell death is theorized to give the brain time to find an alternate blood supply through unblocked arteries, meaning patients may potentially avoid physical and speech impairments caused by ischemic strokes.
Numerous studies have also suggested that therapeutic hypothermia can provide safe and effective adjunctive treatment for migraine headaches. For instance, a 1989 study in ''Headache: The Journal of Head and Face Pain'' showed 64.5% of 45 patients with migraine or migraine plus chronic daily headache evaluated use of a cold wrap for 20 to 30 minutes as mildly, moderately or completely effective. In a 1984 study using a frozen gel pack, 80% of migraine patients reported the pack was effective. Numerous over-the-counter hypothermia caps today offer therapy for headaches.
Side effects
In tests, minor
cardiac arrhythmias
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...
occurred slightly more often in cooled infants, however the effect was not unexpected because mild
sinus bradycardia
Sinus bradycardia is a sinus node dysfunction giving a heart rate that is lower than the normal 60–100 beats per minute (bpm) in humans. Bradycardia is generally defined to be a heart rate of under 60 bpm.
Signs and symptoms
The decreased hear ...
is known to be associated with
hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe h ...
. In tests, all cases were resolved with appropriate therapy. The cold cap system also increased the incidence of scalp
edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...
; however, all cases were resolved prior to or after completion of treatment.
See also
*
Therapeutic hypothermia
Targeted temperature management (TTM) previously known as therapeutic hypothermia or protective hypothermia is an active treatment that tries to achieve and maintain a specific body temperature in a person for a specific duration of time in an e ...
References
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Medical devices
Cooling technology
Caps