sylvania, 2 % of burn admissions were for self-inflict- ed injuries, and another 2 % for assault-by-burning; 95 % were unintentional [78]. Only 2.4 % of admissions to burn centers in Taiwan, ROC, from 1997 to 2003 were for self-inflicted injuries [217].

India has the highest number of cases of intentional self-harm by burning in the world. The majority of victims are young women, as opposed to Europe, where they are more often men in their fourth or fifth decade of life [88, 116].

Comorbidity

Because epilepsy is often untreated in LMIC, it is a frequent initiating factor in many severe burns [139]. During a seizure the epileptic may fall into an open fire or onto a stove. The severity of injury is sometimes and unfortunately exacerbated by traditional beliefs that epilepsy is contagious; victims in Ethiopia are often left to burn because of fear by potential rescuers of contacting the disease by touching the victim [211]. Burns precipitated by epileptic seizures occurred in 44 % of adult burn injuries in a community survey in rural Ethiopia, and 29 % of adult burns admitted to the hospital were precipitated by epileptic seizures [54]. Epilepsy was the most common personal risk factor, other than age, in remote subsistence village of the highlands of Papua New Guinea during 1971 to 1986, where the mortality rates from fire and flames were nearly 15 per 100,000, many times higher than reported rates from other countries [33]. In rural Bangladesh, 0.7 % of all deaths to women (15–44 years of age) were caused by falls into fires during seizure activity; this is an annual rate of approximately 2 per 100,000 [75].

Many Muslim epileptics insist on fasting during the holy month of Ramadan and hence miss their anti-epileptic medications. Therefore, burns in epileptics are commonly seen during Ramadan in Islamic populations. These burns are typically sustained during seizures while in the kitchen or falling on the hot ground (which can reach temperatures over 115 °F). In a prospective study of burns in epileptics in Saudi Arabia, 40 % of injured patients sustained the burn while fasting because they did not take their anti-epileptic medications [11, 12].

Peripheral neuropathy is a disorder commonly caused by leprosy and diabetes mellitus, and results

in sensory loss of the extremities. People with sensory peripheral neuropathy are vulnerable to burn injuries, especially hot water scalds [110]. Handling hot cooking utensils or warming neuropathic feet too close to a fire can also cause deep burns.

One of the reasons that the elderly are at higher risk of sustaining injuries is because of coexisting medical conditions. Seventy-seven percent of burn center patients aged 59 years or older in a singlecenter study had one or more preexisting medical conditions at the time of injury, and in 57 % of patient’s judgment, mobility or both were impaired [132]. In another study, 50 % of octogenarians admitted for burn treatment sustained injury because of a cerebrovascular accident [45]. Physical or cognitive disabilities are distinct risk factors for burns, especially for scald burns or for death from residential fires. Thirty-seven patients with disabilities were admitted to a burn center in Toronto between 1984 and 1992; the majority of them (84 %) were admitted for scald burns in the home. Although some were elderly as well (median age was 58 years), the extent of disability was significant in all cases, including spinal cord disorders or injuries, epilepsy or other neurological disorders. Given the relatively small size of burn (mean was 10 % TBSA), the mortality rate was 22 %, which is high compared to 4 % in the general burn population. The average length of stay for disabled burn patients was 2.8 days per percent body surface area burned, in comparison to the general population of burn patients in whom length of stay is approximately one day per percent burn [16, 22]. Although the relative risk of burns in the elderly with dementia has not yet been established, expert opinion among burn centers is that dementia is a significant risk factor for burns. Indeed, elderly patients with dementia tend to have poorer outcomes from burns injuries, and rehabilitation is very limited [9].

Agents

Flame burns and scalds occur at approximately the same frequency in children under the age of 18 years in some LMIC, including China and Iran [117, 234] . In general, however, and particularly in younger children, scald burns are more common than flame burns

in children. For example, three pediatric hospitals in Mexico noted that the majority of emergency room visits for burns in children under 10 years of age was because of exposure to boiling liquids, most commonly overly hot bath water [99]. Over 75 % of children under the age of 18 hospitalized for treatment of burns in Taiwan, Republic of China, were injured by scalding liquids [221]. In burn centers in the US, scald burns account for nearly half the admissions of children under five years of age. For very young children under two years, flame burns cause only 5 % of admissions; contact burns are more common in this age group, involving over 20 % of admissions (Table 3).

Even when older children up to the age of 18 years are included in analysis, scald burns still outnumber fire and flame injuries by a ratio of 1.6:1 in US burn centers and 5:1 in all US hospitals [201, 16]. Nonetheless, older children and young teenagers between five and 16 years of age experience fewer scald burns than their younger siblings: only 23 % of admissions are for scalds, compared to 38 % for flame burns (Table 3).

Scald burns are very common in adults as well. A study of discharges from all hospitals in Pennsylvania in 1994 (including hospitals without burn centers as well as the six hospitals with burn centers) showed that 56 % of admissions were for treatment of scald burns [78].

Nonetheless, flame burns overall cause more admissions to US burn centers than any other single cause of thermal injury. Through the adult decades, flame burns continue to be the cause for 35 % to 42 % of admissions, and scalds for 15 % to 18 % (Table 3).

Fortunately, the majority of burns of any etiology are small to moderate in size: 86 % of burns admitted to US burn centers 1999–2008 involved less than 20 % of the body surface area [16].

Clothing ignition is a common cause of severe flame burns. Although conflagrations caused 78 % of the deaths in the elderly in the US in 1984, 11 % of fatalities were from clothing ignitions [87]. Women of the Indian subcontinent wearing loose flammable saris (made of cotton or synthetic textiles) are vulnerable to fire deaths when their clothing is ignited while cooking near open flames, particularly if the cooking source is an open fire pit or a small kerosene stove on the ground [66]. Ninety-three percent of burn injuries in rural Ethiopia occurred inside the

home where open fires were used in the common room and often ignite clothing [58]. Likewise, ignition of grass skirts in warm coastal areas of Papua New Guinea account for nearly half of hospitalizations for burns [32].

Flammable fuels are often the agents of fire acceleration or heat production in incidents that result in flame burns. The unsafe use of gasoline was implicated in 87 % of patients in whom the cause of the burn could be identified at single-site retrospective study of burns admitted from 1978 to 1996 in the US [28]. Liquefied petroleum gas (LPG) has replaced kerosene in many households in LMIC as per-capita income has risen and availability of smaller and more affordable LPG cylinders has improved. In Delhi, LPG-related burns were responsible for over 10 % of admissions from 2001 to 2007 [7].

Electrical and chemical burns are rarely reasons for admission in children, occurring less than 2 % of the time, but account for 4 % to 5 % of admissions of adults from 20 to 60 years of age (Table 3). The frequency of admissions for contact burns declines precipitously with age: although one-fifth of admissions of children under two years are for contact burns, only about 5 % of adult admissions are for contact burns (Table 3).

Residential fires

The products of combustion consist of fire gases, heat, visible smoke, and toxicants. The hazards created by these products of combustion include effects of heat on the upper airway, toxicant damage to the sub-glottic respiratory system, impaired vision due to smoke density or eye irritation, and narcosis from inhalation of asphyxiants. These effects lead contribute to restricted vision, loss of motor coordination, impaired judgment, disorientation, physical incapacitation and panic. The resultant delay or prevention of escape from the burning structure leads to injury and death from inhalation of toxic gases and from thermal burns. Extricated survivors may go on to die later in the hospital from complications such as respiratory failure, septic shock, and multiple organ system failure, all of which are rooted in the initial exposure to products of combustion [94].

Smoke is defined as the airborne solid and liquid particulates and fire gases created during combus-

tion and when materials undergo decomposition or transformation by heat [20]. Pyrolysis is the decomposition of a material from heat and does not require the normal atmospheric level of oxygen, leading to incomplete combustion. The toxicant gases produced in a fire can be categorized into separate classes: the asphyxiants which induce unconsciousness, and the irritants which inflame the eyes and respiratory tract. The major threat in most fire atmospheres is carbon monoxide, an asphyxiant produced by incomplete combustion.

The vast majority of deaths due to fires in the US each year occur because of exposure to products of combustion in structure conflagrations. From 1992 to 2001, two-thirds of fire deaths in the US occurred in residential fires [76]. (Although residential fires are the primary cause of fire mortalities, they account for only half of structure fire injuries and less than onethird of the dollar loss for fires.) Residential fires accounted for 76 % of the years of life lost in 2006 in the US due to flame burns [47].

Although most victims of fatal fires die from smoke inhalation, a few will die of thermal injury directly. Temperatures higher than 300 °F are reached within five to ten minutes in building fires, and in an aircraft cabin the temperatures near 500 °F in just five to six minutes [69, 98]. Flashover5 can occur in less than 10 minutes in even a slowly progressing residential fire, at which time temperatures soar from 1100 °F to over 2000 °F in seconds, creating an environment in which survival is unprecedented. In the absence of inhalation of products of combustion and pyrolysis, death can be caused by heat-induced laryngospasm or by vagal-reflex mediated cardiac arrest [202].

Although a well-burning fire produces much more carbon dioxide than carbon monoxide (CO), materials in most structure fires smolder because of rapid depletion of oxygen in the interior of the building. Although the pathophysiology of CO poisoning is well-under-

5Flashover is defined as a transitional phase in the development of a compartment fire in which surfaces exposed to thermal radiation reach ignition temperature more or less simultaneously and fire spreads rapidly throughout the space resulting in full room involvement or total involvement of the compartment or enclosed area. (NFPA 921 - 1992, Guide for Fire and Explosion Investigations, National Fire Protection Association, Quincy, MA, (1992).)

stood, there remains no readily apparent explanation for the observation that the range of carboxyhemoglobin (COHb) tolerated is very wide. Although COHb saturation greater than 35 % can cause death in some people, others have survived COHb saturations as high as 64 % [94]. The average COHb level in fire fatalities is 60 %, with a range of 25 to 85 % [202]. About 10–15 % of CO binds to myoglobin and cytochrome A3, blocking production of ATP and causing muscular weakness, thus exacerbating the difficulties the victim encounters during escape maneuvers [229].

Unfortunately, COHb levels rise rapidly in house fires. When the CO level in inspired air reaches 5 %, COHb rises to 10 % in 10 seconds and to 40 % (a fatal level in some people) in only 30 seconds [209]. A study in East Denmark from 1982–1986 demonstrated that the blood alcohol concentration averaged about 190–200 mg/dl in fatalities from residential fires, and the mean COHb was about 60 % [214]. However, it is clear that some people with pre-existing functional impairments are at risk for increased CO toxicity at lower COHb levels, including children and the elderly, the physically disabled, and those impaired by alcohol, drug or medication intoxication [60, 104]. Largely for this reason, children under age five years and the elderly over 65 years account for 45 % of home fire deaths [108]. Patients with coronary artery disease cannot increase coronary blood flow when COHb rises above 10 % [25]. In addition to inhibiting cognitive responses, ethanol also potentiates the effects of CO such that lower levels of COHb are associated with fatality [46].

Although hydrogen cyanide (HCN), which is produced by the combustions of materials that contain nitrogen such as wool, silk, acrylonitrile polymers, nylons, and polyurethanes, is 20 times more toxic than CO, its role as a causative agent in human fire fatalities is less clear than that of CO. For example, in many fire deaths, COHb is in the toxic range, but cyanide levels are not toxic [119]. Nonetheless, low levels of COHb in other fire fatalities suggest that other toxic gases such as HCN may play a role in causing death [8].

Because oxygen is consumed during combustion, the oxygen level in the inspired air (O2) can drop from 21 % to levels that affect coordination, mentation and consciousness. When O2 drops to 17 %, coordination is impaired, when it drops to 14 %

judgment becomes faulty, and below 6 % unconsciousness occurs [94].

Acrolein is formed from the smoldering of all plant materials (including wood and the natural fibers used in decorations and furnishings), and is a potent sensory and pulmonary irritant. It is extremely irritating to the eyes at concentrations as low as a few parts per million [170].

Level of consciousness and thus ability to escape are affected by drugs and alcohol [8]. One-third to one-half of victims of fatal fires have ingested alcohol [81, 133, 207]. Ethanol intoxication significantly impairs the ability to escape from fire and smoke and is a contributory factor in smoke-related mortality. Whereas victims found near escape exits had blood alcohol levels (BALs) averaging 88 mg/dl, the mean BAL was 268 mg/dl in those found dead in bed, presumably having made no attempt to escape [27]. Moreover, if even one person in the house is impaired by alcohol or drug usage, others in the dwelling are at increased risk of death from fire as well [190].

Perhaps the most deadly combination leading to fatal fires is alcohol and cigarettes. Not only in higher socioeconomic neighborhoods is smoking in bed while inebriated one of the most common causes of death by fire, but also in indigenous communities in North America. Seventy-six percent and 90 % of the adult victims of residential fires in Canadian Indians in Manitoba and Alberta, respectively, were under the influence of alcohol at the time of death [79, 106].

Risk factors for fatal and non-fatal house fire injuries include young or old age, male gender, nonwhite race, low income, disability, smoking and alcohol use [227]. Single, detached mobiles homes had the highest rate of fire deaths of all types of residences [227]. In rural areas, risk of death from a residential fire in a mobile (manufactured) home is 1.7 times the risk in a singleor multiple-family home [190]. In addition, the presence of an ablebodied adult who is not impaired by alcohol or drugs will significantly the odds of survival in a house fire [124]. Burn injuries and fire fatalities are more common in older homes and from fires started in the bedroom or living room from heating equipment, smoking or children playing with fire [104].

Non-electric domestic appliances

In many households in LMIC, especially in rural areas lacking electrification, open flames are common, including floors of huts with open hearths which are used for cooking and warmth, candles, and small kerosene and naphtha stoves and lanterns. The fire risk from these sources are contributed by lack of enclosure for open fires, floor-level location of fires and stoves, instability of appliances, nearby storage of volatile and flammable fuels, flammable clothing and housing materials, and lack of exits [34].

A large number of burn injuries and fire deaths in LMIC are related to the nature of non-electric domestic appliances that are used for cooking, heating, lighting or all three. The incidence of injuries is largely associated with the use of stoves and lamps, and from kerosene (termed paraffin in some countries) and petroleum as well as butane, liquid petroleum gas and alcohol. Associated problems include appliance design and construction, fuel combustion and instability, and mechanical inefficiency. Ignorance of safe usage techniques is also contributory. Industry and government regulations and standards are either nonexistent or not adequately enforces [165].

Informal settlements in densely populated urban areas are often scenes for fires that lead to incalculable property damage and horrific loss of life. From 2002 to 2004, approximately 12 % of households in South Africa were “shacks”, living quarters assembled from highly combustible and toxic materials and usually assembled close to one another on uneven ground. Kerosene is used as fuel for small stoves; the more inexpensive the stove, the more likely it is to tip over or malfunction. During a simulated shack fire triggered by a kerosene stove that was knocked over while burning, the temperature in the shack reached an excess of 1670°F in less than four minutes [159]. Shack fire burns are the second most common reason for admission to burn centers in Cape Town, and the most common cause of shack fires in these cases is the use of kerosene stoves [83].

Serious injuries from kerosene stoves have been documented in Egypt, Ethiopia, India, Nigeria, Pakistan and other LMIC [6, 70, 85, 90, 120, 123, 148, 196]. The underlying problem of kerosene stove-related fires often lies with design issues. Poor design allows