Decompression sickness is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompression. DCS most commonly occurs during or soon after a decompression ascent from underwater diving, but can also result from other causes of depressurisation, such as emerging from a caisson, decompression from saturation, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness.
Cluster headache is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye(s). There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affected side. These symptoms typically last 15 minutes to 3 hours. Attacks often occur in clusters which typically last for weeks or months and occasionally more than a year.
A medication overuse headache (MOH), also known as a rebound headache, usually occurs when painkillers are taken frequently to relieve headaches. These cases are often referred to as painkiller headaches. Rebound headaches frequently occur daily, can be very painful and are a common cause of chronic daily headache. They typically occur in patients with an underlying headache disorder such as migraine or tension-type headache that "transforms" over time from an episodic condition to chronic daily headache due to excessive intake of acute headache relief medications. MOH is a serious, disabling and well-characterized disorder, which represents a worldwide problem and is now considered the third-most prevalent type of headache. The proportion of patients in the population with Chronic Daily Headache (CDH) who overuse acute medications ranges from 18% to 33%. The prevalence of medication overuse headache (MOH) varies depending on the population studied and diagnostic criteria used. However, it is estimated that MOH affects approximately 1-2% of the general population, but its relative frequency is much higher in secondary and tertiary care.
Hyperbaric medicine is a medical treatment in which an increase in barometric pressure over ambient pressure is employed increasing the partial pressures of all gases present in the compressed air. The immediate effects include reducing the size of gas embolisms and raising the partial pressures of all gases present according to Henry's law. Currently, there are two types of hyperbaric medicine depending on the gases compressed, hyperbaric air and hyperbaric oxygen.
An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air can be introduced into the circulation during surgical procedures, lung over-expansion injury, decompression, and a few other causes. In flora, air embolisms may also occur in the xylem of vascular plants, especially when suffering from water stress.
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with, the body and the surrounding gas or liquid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by an expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with the normal function of an organ by its presence. The term is usually applied when the gas volume involved already exists prior to decompression. Barotrauma can occur during both compression and decompression events.
Salt water aspiration syndrome is a rare diving disorder suffered by scuba divers who inhale a mist of seawater, usually from a faulty demand valve, causing irritation of the lungs. It is not the same thing as aspiration of salt water as a bulk liquid, i.e. drowning. It can usually be treated by rest for several hours. If severe, medical assessment is required. First described by Carl Edmonds.
Oxygen therapy, also referred to as supplemental oxygen, is the use of oxygen as medical treatment. Supplemental oxygen can also refer to the use of oxygen enriched air at altitude. Acute indications for therapy include hypoxemia, carbon monoxide toxicity and cluster headache. It may also be prophylactically given to maintain blood oxygen levels during the induction of anesthesia. Oxygen therapy is often useful in chronic hypoxemia caused by conditions such as severe COPD or cystic fibrosis. Oxygen can be delivered via nasal cannula, face mask, or endotracheal intubation at normal atmospheric pressure, or in a hyperbaric chamber. It can also be given through bypassing the airway, such as in ECMO therapy.
A breathing apparatus or breathing set is equipment which allows a person to breathe in a hostile environment where breathing would otherwise be impossible, difficult, harmful, or hazardous, or assists a person to breathe. A respirator, medical ventilator, or resuscitator may also be considered to be breathing apparatus. Equipment that supplies or recycles breathing gas other than ambient air in a space used by several people is usually referred to as being part of a life-support system, and a life-support system for one person may include breathing apparatus, when the breathing gas is specifically supplied to the user rather than to the enclosure in which the user is the occupant.
An oxygen mask is a mask that provides a method to transfer breathing oxygen gas from a storage tank to the lungs. Oxygen masks may cover only the nose and mouth or the entire face. They may be made of plastic, silicone, or rubber. In certain circumstances, oxygen may be delivered via a nasal cannula instead of a mask.
A non-rebreather mask is a device used in medicine to assist in the delivery of oxygen therapy. A NRB requires that the patient can breathe unassisted, but unlike a low-flow nasal cannula, the NRB allows for the delivery of higher concentrations of oxygen. An ideal non-rebreather mask does not permit air from the surrounding environment to be inhaled, hence an event of a source gas failure is life-threatening.
Migraine surgery is a surgical operation undertaken with the goal of reducing or preventing migraines. Migraine surgery most often refers to surgical nerve decompression of one or several nerves in the head and neck which have been shown to trigger migraine symptoms in many migraine sufferers. Following the development of nerve decompression techniques for the relief of migraine pain in the year 2000, these procedures have been extensively studied and shown to be effective in appropriate candidates. The nerves that are most often addressed in migraine surgery are found outside of the skull, in the face and neck, and include the supra-orbital and supra-trochlear nerves in the forehead, the zygomaticotemporal nerve and auriculotemporal nerves in the temple region, and the greater occipital, lesser occipital, and third occipital nerves in the back of the neck. Nerve impingement in the nasal cavity has additionally been shown to be a trigger of migraine symptoms.
Hypnic headaches are benign primary headaches that affect the elderly, with an average age of onset at 63 ± 11 years. They are moderate, throbbing, bilateral or unilateral headaches that wake the sufferer from sleep once or multiple times a night. They typically begin a few hours after sleep begins and can last from 15–180 min. There is normally no nausea, photophobia, phonophobia or autonomic symptoms associated with the headache. They commonly occur at the same time every night possibly linking the headaches with circadian rhythm, but polysomnography has recently revealed that the onset of hypnic headaches may be associated with REM sleep.
Preventive treatment of migraine can be an important component of migraine management. The goals of preventive therapy are to reduce the frequency, painfulness, and/or duration of migraine attacks, and to increase the effectiveness of abortive therapy. Another reason to pursue prevention is to avoid medication overuse headache (MOH), otherwise known as rebound headache, which can arise from overuse of pain medications, and can result in chronic daily headache. Preventive treatments of migraine include medications, nutritional supplements, lifestyle alterations, and surgery. Prevention is recommended in those who have headaches more than two days a week, cannot tolerate the medications used to treat acute attacks, or those with severe attacks that are not easily controlled.
Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing is a rare headache disorder that belongs to the group of headaches called trigeminal autonomic cephalalgia (TACs). Symptoms include excruciating burning, stabbing, or electrical headaches mainly near the eye and typically these sensations are only on one side of the body. The headache attacks are typically accompanied by cranial autonomic signs that are unique to SUNCT. Each attack can last from five seconds to six minutes and may occur up to 200 times daily.
Hyperbaric treatment schedules or hyperbaric treatment tables, are planned sequences of events in chronological order for hyperbaric pressure exposures specifying the pressure profile over time and the breathing gas to be used during specified periods, for medical treatment. Hyperbaric therapy is based on exposure to pressures greater than normal atmospheric pressure, and in many cases the use of breathing gases with oxygen content greater than that of air.
Ditans are a class of abortive medication for the treatment of migraines. The first ditan, Eli Lilly's lasmiditan, was approved by the FDA in 2019.
A built-in breathing system is a source of breathing gas installed in a confined space where an alternative to the ambient gas may be required for medical treatment, emergency use, or to minimise a hazard. They are found in diving chambers, hyperbaric treatment chambers, and submarines.
Inner ear decompression sickness, (IEDCS) or audiovestibular decompression sickness is a medical condition of the inner ear caused by the formation of gas bubbles in the tissues or blood vessels of the inner ear. Generally referred to as a form of decompression sickness, it can also occur at constant pressure due to inert gas counterdiffusion effects.
A breathing apparatus or breathing set is equipment which allows a person to breathe in a hostile environment where breathing would otherwise be impossible, difficult, harmful, or hazardous, or assists a person to breathe. A respirator, medical ventilator, or resuscitator may also be considered to be breathing apparatus. Equipment that supplies or recycles breathing gas other than ambient air in a space used by several people is usually referred to as being part of a life-support system, and a life-support system for one person may include breathing apparatus, when the breathing gas is specifically supplied to the user rather than to the enclosure in which the user is the occupant.
