One of the greatest challenges in healthcare is the management of burn-injured patients. There are important unique aspects that must be considered when managing this population. This the first in a series of articles on burn management during the first 60–90 minutes following injury. This article will examine the basics of thermal burn injury and address the role of prehospital providers in initial management of these patients.
Burn injury involves the largest body organ, the skin. The skin makes up the largest part of the integumentary system (skin, hair and nails). There are 450,000 burn injuries each year in the United States.2 According to the American Hospital Association (AHA), there were 5,795 hospitals in the U.S. in 2011, with 944,277 staffed beds.4 With 123 self-identified burn centers reporting 1,895 beds collectively,3 this yields a ratio of approximately one burn center for every 47 hospitals and one “burn bed” for every 498 beds. Because burn injuries are relatively rare, there are very few locations where serious burn injuries are routinely managed. Regardless of prevalence, it is essential that patients with thermal injuries be managed in dedicated burn centers,5,6 not unlike the need for trauma victims to be cared for at dedicated trauma centers.7–9
Stages of Burn Care
The stages of burn care include what is described as the 6 Rs: rescue, resuscitation, recovery, rehabilitation, restoration and research. The first five deal with managing burn-injured patients, but the overarching theme is research and innovation. Research and innovation is required not only to better understand the phases of burn injury and help develop novel therapeutic interventions, but also to improve prevention programs and produce better methods of public and clinician education. Clearly, the best way to manage a burn is to prevent it altogether. Prevention programs must start early and focus on preschool and school-age children and seniors, who are the most vulnerable to burn injury. EMS and fire service involvement with prevention programs has been shown to reduce incidence of burn injury with at-risk populations.10–13
Rescue starts with a 9-1-1 call and involves the initial response of locating the burn-injured patient and taking steps to get them to a safe area. No rescue should be attempted that places the responder at risk unless they are equipped and trained and the effort is consistent with the mission and direction of their agency.
Resuscitation efforts start with initial patient contact once removed to a safe location and continue through the local hospital emergency department and potential transfer to a burn center. Successful resuscitation efforts require all involved every step along the way to provide care consistent with the current science and body of knowledge for managing burn-injured patients. The teams involved may include EMS, the local ED, a regional ED and trauma center, critical care transport, and helicopter or fixed-wing transport. Everyone involved must be current with a skill set that is not always used on a frequent basis. Airway management, burn injury assessment, fluid resuscitation, wound care and pain control are all critical components of this care, but all have unique features related to the care of burn-injured patients.
Much of the initial care of burn patients is based upon military experiences. As with the Korean and Vietnam conflicts, medical lessons learned from the contemporary Iraq and Afghanistan conflicts have contributed greatly to improving how the acutely injured patient—and specifically the burn-injured patient—is managed.15,16
Recovery can be either an inpatient or outpatient hospital-based effort. For the critically injured, it can represent a long road to regaining as much pre-injury quality of life as possible. According to the American Burn Association (ABA), the seriously burned patient will stay in the hospital intensive care unit one day for each percentile of burn suffered.4 As an example, a patient with a 50% total body surface area (TBSA) of injury will require an ICU stay of approximately 50 days. According to the National Burn Repository (NBR), the average hospital charges in 2010 for patients who survived burn injuries covering 50%–59% TBSA were $661,730 ± $69,285.14 Although we can anticipate that surviving burn-injured patients will require prolonged hospitalization, it is critical that their immediate post-injury phase be managed in a manner to preserve quality of life and optimize patient outcomes.
Rehabilitation can also start in either inpatient or outpatient settings. It is focused on regaining functionality and range of motion for the injured area(s) of the body. Rehabilitation includes the adjustments needed to return home, to work and to the quality of life previously enjoyed. Patients with more extensive burn injuries generally require longer periods of recovery and rehabilitation.
Restoration deals with the aesthetics of the injury. Burn injuries can produce horrific scars, but current technology and surgical interventions allow for remarkably improved final appearances. There once was a time we measured the saving of a life with discharge of a patient physiologically alive from the hospital. Today, an equally important functional measure is quality of life, which includes the patient’s self-image. Furthermore, trending over the past 10 years in the NBR validates a decreased length of stay and decreased mortality for burn-injured patients.14 It is reasonable to conclude that innovations have led to improved care, decreased length of stay and better quality of life.
The Basics of Burn Injury Management
There are three layers of skin: the epidermis, the dermis and the subcutaneous (fatty) tissue also known as the hypodermis. The epidermis is the “protective coating,” basically the outer layer, which is thinnest on the eyelid and thickest on the palms and soles of the feet. The dermis also varies in thickness but contains specialized cells such as hair follicles, sebaceous (oil) and eccrine (sweat) glands, and certain nerve cells. The subcutaneous tissue is a layer of fat where the larger blood vessels and nerves are located, as well as connective tissue.
A burn’s extent and severity are functions of both absolute temperature and the duration of exposure. Of all burn types, thermal burns are the most common. For all burn injuries, the basic focus of care includes airway/breathing, TBSA assessment and fluid resuscitation based on it, wound care and pain management.
Regarding wound management, the wet/dry argument for managing burn injuries has long since been resolved. The key is to use only enough water to remove the heat from the burn, in essence stopping the burning process. Once the wound temperature is normal, handle pain management with either intravenous or intraosseous morphine or a similar medication.
Superficial (First-Degree) Burns
The most common thermal burn injury is a superficial burn, also described as a first-degree burn. Superficial burns are characterized by reddened skin (in patients with lighter skin tone/complexion) and generally are painful for all patients. The most common cause of superficial burns is sunburn. Though superficial burns may be painful, even when much of the body is involved, they typically do not require EMS activation or hospitalization for the burn alone.
Superficial burns should not be included in TBSA calculations. Indeed, one of the most common mistakes clinicians make is including superficially burned portions of the body along with those suffering more significant partial-thickness (second-degree) and full-thickness (third-degree) burns when determining TBSA. (TBSA calculation and the Rule of Nines will be discussed later in the article.) Figure 1 illustrates the effect of first-, second- and third-degree burns on skin layers; Figure 2 shows a patient with a first-degree burn.
Partial-Thickness (Second-Degree) Burns
The partial-thickness burn, also described as a second-degree burn, is characterized by blistering. Quite painful, it is the burn injury most commonly seen by EMS and treated in the ED. Partial-thickness burns do not include superficial/first-degree burns. Management of partial-thickness burn injuries should follow the standard steps for any burn injury. Figure 3 shows a patient with a second-degree burn.
Full-Thickness (Third-Degree) Burns
The full-thickness or third-degree burn is characterized by charring or a thick, leathery appearance of the skin. It includes damage and destruction of the subcutaneous fatty tissue, where nerve endings are located. Pain is an unreliable symptom; patients may report the pain created by the injury as extreme, negligible or in between. Pain may also be reported due to partial-thickness injury in areas contiguous to the full-thickness burn.
Management of the full-thickness burn injury also follows the standard steps. Figure 4 shows a patient with a third-degree burn.
Very serious burn injuries have been called fourth- and fifth-degree burns. These terms describe full-thickness burns that involve muscle tissue (fourth-degree) or bone (fifth-degree). They are rarely and inconsistently used in academic literature.
A review of the literature indicates a gradual transition away from using degrees and toward a more descriptive terminology for burn injuries. Today superficial, partial-thickness and full-thickness are preferred to first-, second- and third-degree.
Assessment and Care
If the initial evaluation determines a burn injury is superficial only, the patient is best managed with rest, limitation or elimination of continued exposure to the heat source, and the provision of oral hydration. While typically outside the bounds of EMS operations, personal care may include over-the-counter treatments such as ibuprofen or a topical anesthetic. Evaluate the use of OTC remedies on a case-by-case basis for each patient based on underlying history and indications/contraindications. Care should always reflect local protocol.
Partial- and Full-Thickness Burns
Care of patients with partial- and full-thickness burns begins with an airway/breathing evaluation, and this should be an ongoing aspect of the continued assessment throughout your time with your patient. Key components of airway assessment include the history (e.g., burn in a confined space), differentiating between steam versus dry heat (steam is worse), physical signs such as a hoarse-sounding cough or stridor noted with breath sounds, sooty-tinged sputum and decreased oxygen saturations. Also, ask family or friends if the patient’s voice seems altered (also an indication of an inhalation injury). If an advanced airway is indicated (according to your protocol), endotracheal intubation is preferred, and using an appropriate-size tube is essential. You may see the patient before significant swelling takes place, and if endotracheal intubation is indicated, your tube may be left in place for several days throughout the patient’s care. A blind-insertion airway device is not preferred in these situations. Inhalation injury will be addressed in more depth in a future article in this series.
Fluid resuscitation is driven by an accurate TBSA assessment using the Rule of Nines. There are other, more precise methods, such as the Lund and Browder chart, but that is a difficult tool where lighting is poor, staffing is limited or caregivers are unfamiliar with the chart. The Rule of Nines offers a timely, concise and reasonably accurate method of assessment (see Figure 5). The two most significant mistakes made with Rule of Nines assessment is including superficial burns in the calculation and including an entire extremity percentage when only a small area is burned.
Fluid resuscitation is best accomplished using lactated Ringer’s (LR), which is the intravenous fluid that most closely mimics the fluid lost in a burn injury. If LR is not available, 0.9% sodium chloride (saline) solution is sufficient. Nevertheless, as soon as LR is available, it should replace the saline solution. Typical fluid resuscitation is driven by the size of the burn and patient’s weight. Potential exceptions include fluid-restricted patients who may need lower infusion rates, such as dialysis patients, and patients with electrical burns, where what is seen may not reflect the full extent of the injury. (Electrical burns will be discussed in a future article.)
The fluid infusion rate should follow the Parkland formula, which is: 4 x patient’s weight in kg x TBSA, infused over 24 hours, with half given over the first 8 hours. A rule of thumb is that for a 50% TBSA injury, the fluid infusion rate for an average-size adult (176 lbs.) is one liter per hour. This is more than a maintenance infusion rate but well less than wide-open. A wide-open IV fluid infusion rate for a patient with a minor or moderate burn is a mistake that can produce significant problems. Charts and smart phone applications are available and incredibly useful in these situations. Nevertheless, the big picture is that burn patients need IV fluids, but not too much too fast.
Wound care should include only enough water to stop the burning process. For minor burns (less than 5% TBSA), sterile or clean water can be used to stop the burning process and manage the pain. However, for moderate and major burns, using excessive fluid for pain management is contraindicated and can, depending on the size of the burn, lead to hypothermia. Do not attempt to drain blisters or debride wound sites.
Slightly elevate all extremities with burn injuries to minimize swelling that will occur during the hours and weeks following a serious burn. This can be accomplished using pillows. Cover the partial-thickness burn with a clean, dry dressing. The patient should be evaluated by a physician at a hospital. Do not continuously flush partial-thickness burn areas with water unless the source of the burn is chemical.
Deep Partial-Thickness, Circumferential Burns
Clinically, there is a distinction between partial-thickness and deep partial-thickness burns. However, for purposes of this work, you should focus on the presence of blisters (which characterize partial-thickness burns) and charredor leatheryskin (which characterizes full-thickness burns) to differentiate between partial- and full-thickness burns. In areas of the body where there is little or no subcutaneous fatty tissue, burns with partial-thickness characteristics may be more critical and are likely to be a deep partial-thickness burns. All burns that can be described as partial- or full-thickness involving the face/ears, hands/feet, and peritoneal/genital area are critical burns.
A condition that is particularly life-threatening is the partial- or full-thickness burn that is circumferential to an extremity or involves significant portions of the chest or abdominal area. With partial- and particularly full-thickness burns, the skin loses its elasticity and contracts. If the burn is circumferential to an extremity or covers a significant portion of the chest or abdomen, the contraction will lead to decreased circulation distal to the injury site. Signs and symptoms include the appearance of a taut or leathery appearance of the impacted tissue, cyanosis or pallor in the area distal to the wound, numbness or a tingling sensation and diminished or loss of pulses. The aforementioned signs and symptoms point to a condition known as compartment syndrome. This is life-threatening, limb-threatening or both, depending on where the injury is located.
For circumferential chest wall burns, as the burn injury begins to manifest, the skin will shrink and impede the inspiration and expiration. This increased workload on the cardiovascular system can also be life-threatening.
Compartment syndrome can only be relieved by escharotomy/fasciotomy. Escharotomy is a surgical incision that cuts through the dead tissue (eschar). Fasciotomy is a surgical incision that cuts into the (subcutaneous fatty) fascia tissue. These terms basically describe the same procedure and are routinely interchanged in managing circumferential burns. The procedure is typically performed by a trained surgeon.
For minor burns, clean, dry dressings are sufficient. Burn-center surgeons generally prefer the same for moderate and severe burns, since anything applied will have to be removed during the debridement process.
There are many commercially made burn-specific dressings impregnated with a variety of additives. Commercially made dressings that include some aspect of a silver solution have historically been recommended for situations where the time between injury and admission to a burn center is prolonged. Soldiers and Marines have had these dressings applied early in their management in Iraq and Afghanistan and maintained until arriving 72–120 hours later at Brooke Army Medical Center in San Antonio,15,16 where most military personnel with burn injuries are managed. For civilians, when a burn center can be accessed in less than 6 hours, there is no conclusive evidence of benefit to commercially made impregnated dressings.
There are other commercially sold dressings reported to have wound-healing properties without silver-based active ingredients. These may aid in healing if you have an extended transport time. However, as with the silver-impregnated dressings, they tend to be expensive, and while the preliminary data for several of these dressings may be promising, there is no conclusive evidence of their added value to a patient whose injury is managed at a burn center in the first few hours.
The first recommended purchase specifically for burn care, outside of what is typically found on an ambulance, is lactated Ringer’s IV fluid (LR), provided it is on an agency’s approved formulary. LR is inexpensive and has a similar composition to the fluid being lost during burn injury.
For agencies with caches of supplies for atypical medical disasters, impregnated dressingsoffer great value. While it may be cost-prohibitive to stock supplies on each ambulance for single burn patients, in an MCI, where having multiple patients with burn injuries could extend the times between injury and definitive treatment, impregnated dressings could be used more effectively.
For EMS agencies not within 6 hours of a burn center, impregnated dressings may also be of benefit. Consult your local medical director and the regional burn center regarding the best dressing to be purchased and stocked on ambulances and in MCI response caches.
Morphine sulfate (MS) is an excellent medication for managing burn-injured patients. It is given in 2-mg increments every 5 minutes until the desired pharmacological outcome (pain relief) or side effects (hypotension, nausea/vomiting, hypoventilation) are noted. An alternative is fentanyl (Sublimaze), given at 50–75 mcg IV, then 25 mcg until either a maximum dose of 200 mcg is reached or clinical improvement is noted. Always follow your local protocol for pain management.
The total drug used with these medications can be different for burn-injured patients. While MS typically has an endpoint of 10 mg, it is not unusual for critical burn patients to receive 30 or 40 mg in the first 24 hours following injury. This is an important consideration when transferring patients over long distances to regional burn centers. You may need additional medication for such transfers.
Antiemetic medications such as ondansetron (Zofran) or promethazine (Phenergan) may be needed as well because MS and other pain medications can lead to gastrointestinal discomfort and vomiting. Follow your local protocol in use of these medications.
The most effective means of administering pain medications is through an existing IV. If an IV cannot be secured, IO access is sufficient, provided is consistent with local protocol and your scope of practice. Intramuscular injections are generally contraindicated for burn-injured patients. For serious or critical burn injuries, the quality and quantity of absorption for an IM injection is unpredictable, and multiple IM-administered doses can be dangerous. While there are other methods of administering pain medication, for the burn-injured patient, the preferred routes are IV and IO. Any other means of administration should be based on your protocols with the guidance of your medical director.
Burn Center Referral
Relying on the American Burn Association’s Burn Center Referral Criteria,1 minor burns are generally not referred to burn centers. Minor and superficial burns generally do not involve EMS outside of aid stations at mass gatherings, and superficial burns for otherwise-healthy patients with no concomitant injuries or medical conditions generally are not seen at hospitals.
Serious or potentially serious burns include partial- and full-thickness burns between 5%–15% TBSA. These should be evaluated by a physician at a hospital. Serious burns also encompass inhalation burns, even with no obvious sign of thermal injury involving the dermis, and small (
A critical burn is a partial- or full-thickness burn that involves a key area of the body (ears, face, hands, feet, genitalia, perineum or major joints) or is greater than 15% TBSA. Other critical burns include steam inhalation burns, electrical shocks with contact points or lightning injuries, significant chemical burns and burns from radiation sources. While it may seem an overstatement to call a burn of less than 30% TBSA critical, according to the National Burn Repository, the mortality rate for burns covering 0.1%–29.9% TBSA for all age groups over the past 10 years is greater than 12%.14
Patients who present with time-sensitive injuries and illnesses such as trauma, STEMI, stroke and burns rely upon EMS providers who are educated and equipped to manage acute events outside the hospital. These patients have their best outcomes when triage and transport guidelines identify the best location for their care, which may not be in the same community. Just as traumatically injured patients have their best outcomes at specialized trauma centers, burn-injured patients fare better at burn centers. EMS destination plans and protocols should reflect hospitals where such appropriate specialty services are available.
Care of the burn-injured patient can be quite challenging. This is due not only to the complexity of their physiology, but also to the infrequency of the first responder’s exposure to burn victims. While this article incorporates a best practices approach to burn-injured patients, rely on your local protocol to guide your practice.
Future articles in this series will cover blast injuries and care; chemical burns; electrical burns; inhalation burns; fluid resuscitation; interfacility transfers of burn patients; pediatric considerations; and radiation injury/burn considerations.
1. American Burn Association. Resources for Optimal Care of the Injured Patient, 2006.
3. American Burn Association. Burn Care Resource Directory, 2011.
4. American Hospital Association. AHA Hospital Statistics, 2011 Edition.
5. Holmes JH 4th, Carter JE, Neff LP, et al. The effectiveness of regionalized burn care: an analysis of 6,873 burn admissions in North Carolina from 2000 to 2007. J Am Coll Surg, 2011 Apr; 212(4): 487–93.e1–6, discussion 493–5.
6. Haik J, Weissman O, Givon A, et al. Examining national burn care policies—is the Israeli burn care alignment based on national data? J Burn Care Res, 2012 Jul; 33(4): 510–7.
7. Cairns BA, Stiffler A, Price F, Peck MD, Meyer AA. Managing a combined burn trauma disaster in the post-9/11 world: lessons learned from the 2003 West Pharmaceutical plant explosion. J Burn Care Rehabil, 2005 Mar–Apr; 26(2): 144–50.
8. Takanishi DM Jr., Ho HC. Trauma system development: crisis at our doorstep. Hawaii Med J, 2006 Jun; 65(6): 172–4.
9. Galvagno SM Jr., Haut ER, Zafar SN, et al. Association between helicopter vs. ground emergency medical services and survival for adults with major trauma. JAMA, 2012 Apr 18; 307(15): 1,602–10.
10. Clare J, Garis L, Plecas D, Jennings C. Reduced frequency and severity of residential fires following delivery of fire prevention education by on-duty fire fighters: cluster randomized controlled study. J Safety Res, Apr 2012; 43(2): 123–8.
11. Parmer JE, Corso PS, Ballesteros MF. A cost analysis of a smoke alarm installation and fire safety education program. J Safety Res, 2006; 37(4): 367–73.
12. Duchossois GP, Nance ML, Garcia-Espana JF, Flores J. Sustainability of an in-home fire prevention intervention. J Trauma Nurs, 2009Oct–Dec; 16(4): 194–8; quiz 199–200.
13. Grant E, Turney E, Bartlett M, Winbon C, Peterson HD. Evaluation of a burn prevention program in a public school system. J Burn Care Rehabil, 1992 Nov–Dec; 13(6): 703–7.
14. American Burn Association. National Burn Repository, Report of Data From 2001–2010.
15. Cancio LC, Horvath EE, Barillo DJ, et al. Burn support for Operation Iraqi Freedom and related operations, 2003 to 2004. J Burn Care Rehabil, 2005 Mar–Apr; 26(2): 151–61.
16. Chung KK, Blackbourne LH, Wolf SE, et al. Evolution of burn resuscitation in Operation Iraqi Freedom. J Burn Care Res, 2006Sep–Oct; 27(5): 606–11.
18. Federal Emergency Management Agency. Typed Resource Definitions, Emergency Medical Services Resources. Vol. 508-32009:21.
Randy D. Kearns, DHA, MSA, NREMT-P (ret.), is program director for the North Carolina Burn Disaster Program and administrator of the EMS Performance Improvement Center at the University of North Carolina School of Medicine.
Charles B. Cairns, MD, FACEP, FAHA, is a professor and chair of emergency medicine at the University of North Carolina School of Medicine.
James H. Holmes, IV, MD, FACS, is director of the Wake Forest Baptist Medical Center’s Burn Center and associate professor of surgery at the Wake Forest School of Medicine.
Preston B. Rich, MD, MBA, FACS, is a professor of surgery and chief of trauma, critical care and emergency surgery at the University of North Carolina School of Medicine, as well as a firefighter and medical advisor for the Chapel Hill (NC) Fire Department.
Bruce A. Cairns, MD, FACS, is director of the North Carolina Jaycee Burn Center and the John Stackhouse Distinguished Professor of Surgery/Microbiology and Immunology at the University of North Carolina School of Medicine.
Sidebar: Common Challenges
Overestimation of burn size, TBSA assessment
The most common mistake made by clinicians is including first-degree burns in the total body surface area of injury (TBSA) when assessing the percentage of burn. Making an error when estimating the TBSA will create a cascade impacting fluid resuscitation. This could also contribute to overtriage, leading to an incorrect (and typically less convenient and more costly) destination choice.
Over-resuscitation with excessive fluids
For most clinicians, their last burn injury education was a 45–60-minute lecture during a trauma program where the day included a focus on large-bore venous access and significant fluid resuscitation. While it is true that burn-injured patients need IV fluids, it’s generally not at the rate or volume of a traumatic injury with significant bleeding.
While it is important to ensure that what caused the burn is not continuing to burn the patient, it is contraindicated to soak or continuously irrigate your patient with sterile or clean water. Stop the burning process, but once that’s done, additional cooling is potentially harmful. While it can aid in pain management, it can also plunge the patient into hypothermia. Once you can touch the skin around the burn and it is not hot, no additional fluid should be used.
Normal saline vs. lactated Ringer’s
Many EMS systems have only one intravenous solution from which to choose: normal saline. The IV fluid most alike the interstitial fluid being lost with a burn injury is lactated Ringer’s. If the only fluid available is normal saline, use it until LR is available, but understand it is less than ideal and could create complications if used in excess.
What to buy
The “burn kit” of many years ago included sterile sheets, sterile scissors and 2 liters of sterile water. A later addition was impregnated dressings with cooling properties. Today it’s important to focus on the basics of an ample supply of clean, dry dressings, pain management medication(s) and lactated Ringer’s IV solution.
Sidebar: Burn Center Referral Criteria
Seriously and critically injured burn patients are best managed in burn centers. Most likely to benefit from admission to a burn center are those with:1
1. Partial-thickness burns >10% TBSA;
2. Burns involving the ears, face, hands, feet, genitalia, perineum or major joints;
3. Full-thickness burns;
4. Electrical burns, including lightning injury;
5. Chemical burns;
6. Radiation burns;
7. Inhalation burns;
8. Preexisting medical conditions that could complicate management, prolong recovery or affect mortality, such as end-stage renal disease;
9. Burns and concomitant trauma (such as fractures) in which the burn injury poses the greatest risk of morbidity or mortality. Evaluate trauma patients first to determine the extent of injury, and if in doubt, go to the trauma center first;
10. Burn injuries in pediatric patients. Not all burn centers accept pediatric patients. Check with your regional burn center to determine what age limitations it may have and plan accordingly;
11. Need for special social, emotional or rehabilitative interventions. Not all burn centers are colocated with trauma centers. Not all accept patients with, for example, radiation injuries. Call them first, create a relationship and understand their capabilities and limitations.
While burn injury is commonly associated with trauma and the two share many similarities, they should not be confused. Patients with penetrating or blunt force trauma can exsanguinate or suffer other grave consequences even when the most optimal care is provided. The definitive solution for such patients is rapid movement to a trauma center and the care of a trauma surgeon. A burn injury, properly managed in the prehospital and community hospital setting, is far less likely to cause grave consequences over the same period of time. As noted in military experience, burn-injured patients have good outcomes over much larger intervals from initial injury to arrival at a burn center. While this is not a reason to delay the transfer of burn-injured patients, it is critical to note where trauma is suspected in addition to the burn injury. For optimal care, burn-injured patients are best managed at burn centers that have trauma services as well.
Figure 5: Total Body Surface Area (TBSA) and the Rule of Nines
The basic approach is to rely on the Rule of Nines to determine the extent of injury. Do not include superficial/first-degree burns in the calculation. For partial areas, either estimate percentages of percentages (e.g., half the arm is 4.5%, a quarter of the leg is 4.5%, etc.) or use the size of the anterior surface of the patient’s hand as an approximate gauge of 1% for all parts of the body. For the adult, arms are 9% each, legs are 18% each, the head is 9%, the genitalia is 1%, the anterior chest and abdominal area is 18%, and the posterior chest and low back is 18%.