------------------------------------------------------------------------------- TITLE: Burns of the Head and Neck SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: September 5, 1989 RESIDENT PHYSICIAN: Sharen J. Knudsen, M.D. FACULTY: Karen H. Calhoun, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." Introduction: Overview of the Epidemiology 2,000,000 people burned each year 300,000 require hospitalization 12,000 deaths 25-75% of all burns involve the head and neck Special considerations in the management of facial burns: Head is 9% of the total body surface area (TBSA), recall in infants this area is even greater. Preserving function of facial structures of great importance in rehabilitation. Esthetic considerations greatest in the head and neck area. Inhalational injuries often accompany burns of the head and neck. Types of burns: Thermal: Flame, Flash, and Scald Chemical: Cutaneous or toxic ingestion Electrical Severity of burns is a function of intensity of burning agent and duration of exposure. Steam has about 4000 times the burning energy than does air. This is due to the heat of vaporization of water from liquid to gas phase. Hot oils have greater thermal energy than does hot water because the flash point is higher. Thus hot oils can reach temperatures into the 200oC range and still remain liquid. Duration of exposure may be related to length of time in direct contact or prolonged burning from un-neutralized chemicals. Scalds with viscous oils will be more severe than with hot water. Plastic polymers in clothing will melt onto the skin and produce severe burn injuries. The time and temperature relationship has been extensively studied by Moritz and Henriques: Temp(c) Time (min) 44 90 47 45 51 3 70 2Sec Acute Management of Burn Wounds Follow the ABC's of trauma care. Think of possible associated injuries. Begin adequate fluid resuscitation. Management of Inhalational Injury: Begins with consideration of the diagnosis When to suspect inhalation injury: Historical: History of closed space, loss of consciousness, intoxication, very small or immobile victim. Physical examination: Burn to face, singed nasal vibrissae, mucosal injury, expectoration of carbonaceous sputum, hoarseness, or early detection of deteriorating respiratory status manifested by air hunger tachypnea, dyspnea, and cyanosis. Laboratory: PaO2 less than 80 on admission, elevated carboxyhemeglobin, Xenon 133 washout* studies and pulmonary function studies. Xenon 133 washout studies: Normal individuals will clear Xenon133 from the lungs by 90 seconds. Victims with inhalational injury will retain Xenon133 labeled gasses trapped behind plugs of debris in the injured lung. Radioisotope trapping occurs with COPD, pulmonary blebs, asthma. Agee found Xenon perfusion-ventilation scans performed prior to the 4th day to be useful in predicting 87% of inhalation injuries. Pulmonary function studies: Smoke inhalation injury produces a severe obstructive defect. Surface burns produce a restrictive defect. FVC and FEV1 are altered within 9 hours of injury and generally precede Xray findings. CHEST RADIOGRAPHS ARE RARELY ABNORMAL IN THE FIRST 24 HOURS POST-BURN. Fiberoptic Bronchoscopy: Can be utilized as both a diagnostic and a therapeutic modality. Accurate assessment of degree of mucosal injury important. CAUTION: if the patient is in severe hypovolemic shock, the edema seen with inhalational injury may be absent. After adequate fluid resuscitation, edema of the upper airway may obstruct acutely. When combined with spirometry, there is a 96% accuracy in diagnosis of severe inhalational injury. Mechanism of injury: Pulmonary injury may be a consequence of: 1. inhalation of toxic substances 2. over-zealous fluid resuscitation 3. direct injury to the tracheo- bronchial tree 4. severe systemic derangements (ARDS) Physiologic response to heat is edema. This edema is particularly common in the supraglottic structures. Direct heat rarely involves the infra- glottic structures because of the cooling properties of the upper airways and the protective mechanism of the glottis. STEAM injury is a notable exception. Irritation and inflammation of the respiratory tract is caused by noxious gasses and smoke. The mere presence of carbon monoxide, carbon dioxide, methane, helium, nitrous oxide can cause asphyxia when these exceed 20-30 volumes percent of the inspired air. Carbon monoxide results from incomplete combustion. The darker the smoke, the higher the concentration of CO. CO competes with O2 for binding sites on hemoglobin, (210 times the affinity for hgb as O2). 30% conversion of Hgb to metHgb produces hypoxia. Skin may remain red. Hydrogen cyanide is produced by combustion of wool, silk, polyurethane foam and phenol resins found in home construction. Level of 3-10 mg/L is lethal. The organic aldehydes produce a chemical pneumonitis by direct irritation of the tracheobronchial tree. These patients must be followed for development of bronchiolitis obliterans. Inhalation Injury: Epidemiology 2-3% of burn patients suffer primary inhalation injury. 50-75% have facial burns 50% have burns greater than 50% TBSA. Clinical Stages according to Martin and Stone: 1. Ventillatory insufficiency (stage I) Occurs between 0 and 20 hours. Severe bronchospasm and alveolar damage with disruption of the alveolar capillary membrane characterized this phase. Pulmonary resistance is increased while compliance is decreased. Arteriovenous shunting produces a progressive hypoxia. Mortality is 64.5% 2. Pulmonary edema (stage II) Occurs between 8 and 36 hours Etiology secondary to pulmonary burn, over hydration, and cardiac pathology. Mortality 40.5% 3. Bacterial pneumonia (Stage III) Occurs 3-11 days post-burn. Occurs in virtually all patients who survive stages I and II. Staph and pseudomonas are offenders. Mortality is 20% Tracheotomy versus endotracheal intubation The great debate Background: Much cited study by Eckhauser in 1977 9 patients with tracheotomy were compared to 16 patients without. They found 100% mortality in the trach group versus 25% mortality in the non-trach group. Older literature: Moncreif 1959 Isaev 1968 Nelson et al 1957 Give broad endorsement to tracheotomy in burn setting. More recent literature: DiVincenti 1971 Walker 1978 Eckhauser 1977 Suggest to avoid tracheotomy at all costs. The latest literature: Calhoun 1988 Jones et al 1989 Sataloff 1984 Indication for tracheotomy include: Upper airway obstruction 1. intubation preferred 2. Cricothyrotomy in emergency situations 3. Tracheotomy as a last resort. Prolonged intubation 1. Definition of prolonged debated 2. 3 weeks accepted by most Children 1. Felt to be difficult to intubate 2. Felt to "fight the tube" and worsen the injury 3. Hotly debated issue Laryngeal burn 1. Rare injury 2. More survivors of serious burns. A final comment: "When compared with matched groups of burn patients with and without inhalation injury stratified by burn size, the mortality of patients who underwent tracheotomy was higher only in cases associated with burns of less than 30% TBSA. These differences were not statistically significant." Jones, et al. Ann Surg. April 1989 Sequelae of Tracheotomy in burn patients: Historically thought to have more adverse sequelae with tracheotomy. Careful examination of the patient groups showed that the sicker patients received trachs. 28 of 99 patients who underwent tracheotomy had late upper airway sequelae including tracheal stenosis, tracheoesophageal fistula and tracheoarterial fistula. Management of Cutaneous Wounds: Clean wounds in tub. Leave intact blisters intact Debride ruptured blisters Administer tetanus prophylaxis Apply moist dressings to cover coagulum Silver sulfadiazine incomplete penetrance of eschar transient leukopenia Mafenide (Sulfamylon) deep penetration carbonic anhydrase inhibitor can produce acid base disturbances. painful on application Polysporin well tolerated used at Shriner's Hospital on faces Tangential excision versus separation of eschar Coverage using skin grafting techniques Concept of facial esthetic units Preservation of key areas oral commissure medial canthus Position of comfort = position of contracture Incidence of hypertrophic scarring is reduced in injuries treated by grafting. Grafts should not be meshed. Full thickness or thick split thickness grafts are desirable. Principles of Chronic Care Scars must mature before reconstruction attempted. Concept of the myofibroblast, as described by Guido Majno, is a typical fibroblast with features of smooth muscle. The wound contracts in response to the contractile nature of this cell and is thought not to be dependent on collagen biosynthesis. Burn scar contracture can be controlled by the use of pressure, traction, and exercise. Pressure garments, facial masks made of Uvex, and neck splints all play a role in the rehabilitation effort. Rehabilitate derives from the Latin root habil meaning to cloth. In burn care we are literally re-clothing the body with skin. Areas of special concern: 1. Lids: The recessed anatomy of the lids and orbit often protect the lids from third degree burns. When the lids are burned, their thin skin often results in full thickness losses. These must be treated aggressively. Principles of grafting lids: Full thickness nonmeshed grafts to lower lids and either split thickness or full thickness to the upper lids. Ideal donor sites are: supraclavicular or post auricular areas. Need to bolster to prevent slough. Avoid tarsorrhaphy. Complications: Ectropion. Epicanthal folds Epiphora Shortening of transverse palpebral fissure 2. Scalp Generally protected by hair. Bone, either outer table or inner table may be burned as well. This can be treated by three methods: 1. Debridement of all burnt bone coverage with local flaps. 2. Drilling holes in the outer cortex allowing granulation buds to erupt through the holes. Grafting on a healthy bed of granulation tissue. 3. Allow all dead bone to gradually granulate in from periphery. A sequestrum will form which may require later removal. Complications: Allopecia Loss of hairline contours 3. Ears 90% of head and neck burns involve the ears. Anatomy makes them vulnerable to injury. Treatment predicated on depth of burn injury. Basic principle is to avoid pressure on the burnt auricle. Some recommend excision of all eschar to vital tissues, even with exposure of cartilage. Others recomend treatment with topical preparations. Gentamicin iontophoresis is touted to achieve rapid healing with little to no deformity. Greminger treated 11 ears in 8 patients with chondritis with good results. Recent article reports high levels of gentamicin are detected in the cartilage of burnt tissues treated with iontophoresis. 4. Nose: Thick skin covering the nose resists thermal injury. When burned, either the skin overlying the bony cartilagenous framework is often lost. Damage to the cartilage can result in a skeletonized nasal deformity. Reconstruction must accomplish three goals 1. Restoration of bony cartilaginous framework. 2. Inner surface of nasal scaffolding must be restored. 3. A single esthetic unit with color match should be used to graft the nasal dorsum. 5. Perioral Region Circumferential contracture limits the aperture Burns resulting from biting an electrical cord can result in severe commissure burns involving all layers of the mouth. These should be treated conservatively with splinting. 6. Neck Prevention of contracture a major concern and is accomplished with splinting. Grafting to cover open areas. Z-plasty to release mature scar contracture often required. Conclusion: Head and neck burns pose some of the greatest challenges to the burn surgeon. Involvement early in the course of the burn patient management by the otolaryngologist may result in better outcome in both the critical area of airway management and esthetic reconstruction. --------------------------------END--------------------------------------------