Burns, HIV/AIDS Flashcards
Mechanisms of Burn Injury
Thermal Injury (cause, severity)
Caused when the skin comes in contact with a source of sufficient temperature to cause cell injury by coagulation.
- Flame, scalding liquids, steam, direct contact with heat source (heater, metal, etc)
Severity of injury is related to the heat intensity and the duration of contact.
- A temperature of 140°F causes full-thickness tissue destruction in as little as 3-5 seconds.
Mechanisms of Burn Injury
Chemical Injury (cause, severity)
Categories
Causes by contact, inhalation of fumes, ingestion, or an injection.
Severity is related to the type, volume, duration of contact and concentration of the agent.
- Tissue damage from chemical burns continues until the chemical is completely removed or neutralized
3 Categories of Chemical Agents
1) Alkalis
- Examples: oven cleaners, lye, wet cement, and fertilizers
- Cause more severe injury than acids
- Loosen tissue through protein denaturation and liquefaction necrosis, allowing the chemical to diffuse deeply into the tissue.
- Bind to tissue proteins, making it more difficult to stop the burning process.
2) Acids
- Examples: bathroom cleansers, rust removers, pool chemicals
- Depth of injury tends to be limited.
- Exception: Hydrofluoric Acid burns which may be lethal
- Causes hypocalcemia by rapidly binding to calcium in the blood
3) Organic Compounds
- Examples: phenols and petroleum productions (gasoline, kerosene, chemical disinfectants)
- May produce cutaneous burns and can be absorbed with resulting systemic effects.
Systemic Effects of Petroleum Products
CNS Depression
Hypothermia
Hypotension
Pulmonary Edema
Intravascular Hemolysis
Mechanisms of Injury
Electrical Injury
Caused by contact with varied electrical sources such as household or industrial current, car batteries, electrosurgical devices, high0 tension electrical lines and lightning.
High voltage (>1000 V) or low voltage (<1000 V)
Electricity flows by alternating current (AC) or direct current (DC)
Tissue damage occurs through the process of converting electrical energy to heat.
- Heat energy is often greatest at points of contact (entry and exit), usually the extremities.
Electricity follows a path of least resistance.
- Often along the top of the bone causing extensive deep muscle damage
- Significant injury may be present even when skin and superficial muscle appear uninjured.
Electrical Injury
Alternating Current vs. Direct Current
Alternating Current (AC)
- Most home and commercial applications
- Electric charge sporadically changes direction.
- Higher probability of producing cardiopulmonary arrest by ventricular fibrillation
- Causes tetanic muscle contraction that may “lock” the patient to the source of electricity and paralyze the respiratory muscles.
Direct Current (DC)
- Lightning and car batteries
Mechanism of Burn Injury
Inhalation Injury (causes, clinical indicators)
Caused by inhalation of smoke, chemical toxins, and products of incomplete combustion.
Diagnosed based on injury history, clinical signs, and bronchoscopy findings.
Clinical Indicators of Inhalation Injury
- History of exposure in confined or enclosed space
- Facial burns
- Singed nasal hairs
- Presence of soot around mouth and nose and in sputum
- Abnormal breath sounds
- Signs of respiratory distress (accessory muscle use, tachypnea, retractions, stridor, hoarseness, etc)
- Elevated carboxyhemoglobin levels
- Abnormal ABG
Stimulates an airway inflammatory response, often resulting in lung damage.
- Typically warrant ICU admission even if there are no surface burns.
Types of Inhalation Injury
Carbon Monoxide Poisoning
- Patho
- How to detect
Most frequent cause of death at the injury scene
Released when organic compounds are burned.
Binds to hemoglobin to form carboxyhemoglobin (COHgb) and prevents red blood cells from transporting oxygen to body tissues, leading to systemic hypoxia.
May be difficult to detect.
- PaO2 is unaffected**
- ABG analysis and pulse oximetry are usually normal**
- Carboxyhemoglobin level (percentage of hemoglobin molecules that are bound with carbon monoxide) should be measured **
<10% - 15%: No symptoms, or minimal changes in visual acuity and headache
15% - 40%: CNS Dysfunction: restlessness, confusion, impaired dexterity, headache, dizziness, nausea/vomiting
40% - 60%: Loss of consciousness, tachycardia, tachypnea, seizures, cherry red or cyanotic skin
>60%: Coma, usually death
Types of Inhalation Injuries
Cyanide Poisoning
- Patho
- Clinical Indicators
Occurs from inhalation of smoke byproducts.
Combustion of household synthetics (carpets, plastics, vinyl furniture, upholstered furniture) is the primary source of exposure.
Impedes cellular respiration and oxygen use by binding with the aa3-type cytochrome c oxidase.
- Inhibits cell metabolism and ATP production, resulting in a shift to anaerobic metabolism.
- Leads to lactic acidosis and death.
Clinical indicators of Cyanide Poisoning
- Patient involved in a closed space fire
- Unexplained hypotension
- Unexplained hypoxemia
- Lactic acidosis
Types of Inhalation Injury
Injury Above the Glottis
- Cause
- Clinical Manifestations
Caused by breathing in heat or noxious chemicals that are produced during the burning process.
High risk for airway obstruction due to edema resulting from upper airway thermal injury.
Clinical Manifestations
- Hoarseness
- Dry cough
- Labored or rapid breathing
- Difficult swallowing
- Stridor
Types of Inhalation Injury
Injury Below the Glottis
- Cause
- Clinical Indicators
- Caused by breathing noxious chemical byproducts of burning materials and smoke.
- Extensive damage to alveoli and impaired pulmonary functioning results
- Hallmark sign: Carbonaceous Sputum (soot in secretions)**
- Tracheal and bronchial constriction and spasms (wheezing) can occur within minutes to several hours after injury.
- ARDS may develop within the first few days.
- Mucosal sloughing may occur within 4-5 days.
- Initial chest x-rays are often normal, but may later show reduced lung expansion, atelectasis, and diffuse lung edema or infiltrates.
Superficial Burns
- Degree of Injury
- Morphology
- Healing Time
- Wound Characteristics
1st Degree
Involve only the first layer of skin or the epidermis
Typically heal in 3-5 days without treatment
NOT INCLUDED in burn size (extent) calculations**
Wound Characteristics
- Pink or red
- Dry
- Painful
Superficial Partial Thickness
- Degree of Injury
- Morphology
- Healing Time
- Wound Characteristics
2nd Degree
Involve the epidermis and a limited portion of the dermis
Heal by growth of undamaged basal cells within 7-10 days
Wound Characteristics
- Moist
- Pink or mottled red
- Very painful
- Blisters
- Blanches briskly with pressure
Deep Partial Thickness
- Degree of Injury
- Morphology
- Healing Time
- Wound Characteristics
2nd Degree
Involve destruction of the epidermis (complete destruction) and most of the dermis
May heal spontaneously in 2-4 weeks, but are often excised and grafted to reduce healing time and improve cosmetic results
Wound Characteristics
- Pale, mottled, pearly red/white
- Moist or somewhat dry
- Typically less painful than superficial partial thickness
- Blanching decreased and prolonged
- Difficult to distinguish from full-thickness injury
Full Thickness Burns
- Degree of Injury
- Morphology
- Healing Time
- Wound Characteristics
3rd - 4th Degree
Destruction of all layers of the skin down to or past the subcutaneous fat, fascia, muscles, or bone
Creates a thick, leathery, nonelastic, coagulated layer of dead, necrotic tissue called eschar
Nerves are destroyed, resulting in a PAINLESS wound**
Always require skin grafting for permanent wound closure
3rd Degree
- Involves Epidermis, Dermis and Underlying Subcutaneous Tissue
- Does not Heal (Requires skin grafting)
- Thick, leathery eschar
- Dry
- White, cherry-red, or brown-black
- Painless
- Does not blanch with pressure
- Thrombosed blood vessels
4th Degree
- Involves Underlying Fat, Fascia, Muscle, Tendon and/or Bone
- Does not Heal (May require amputation or extensive debridement)
- Black, charred, thick, leathery eschar may be present
- Bone, tendon, or muscle may be visible
Calculating Percentage of Total Body Surface Area
Palm Method
Rule of Nines
Estimated by summing all areas of partial- and full-thickness burns – Superficial burns ARE NOT included.
Palm Method
- Use the size of the patient’s palm (including fingers) to calculated injury extent of irregular or scattered small burns.
- Palm represents 1% of TBSA.
Rule of Nines
- Head: 9%
- Each arm: 9%
- Back: 18%
- Anterior Trunk: 18%
- Groin: 1%
- Each leg: 18%
Physiological Responses to Burn Injury
Localized Tissue Response
3 Zones of Thermal Injury
Zone of Coagulation
- The area that had the most contact with the heat source and is the location of the most severe damage.
- Protein coagulation, eschar is often present, and the patient often reports no pain to the area because all nerve cells are damaged.
Zone of Stasis
- Immediately surrounds the zone of coagulation.
- Characterized by damaged cells and impaired circulation.
- Area most at risk for conversion if adequate resuscitation is not completed.
- Under resuscitation causes the burn to become deeper because of limited blood flow.
Zone of Hyperemia
- Area of increased blood flow in an effort to bring key nutrients for tissue recovery.
Physiological Responses to Burn Injury
Cardiovascular (shock phases)
Burn Shock: greatest initial threat to a patient with major burn (1st 24 hrs)
*Combination of distributive and hypovolemic shock
*Results from a massive fluid shift
*The body’s initial inflammatory protective mechanism leads to increased capillary permeability causing electrolytes, water, plasma, and proteins to leak out of the intravascular space and into the interstitial space.
*Fluid loss within the vascular space increases the viscosity of the blood
- Sluggish blood flow
- Decreased oxygen delivery
- Overall decreased cardiac output
- Elevated hemoglobin
*Fluid leakage occurs during the first 8-36 hours, peaking at 24 hours post-burn.
*If fluid resuscitation is not adequate, patient shows symptoms of shock
- Hypotension
- Tachycardia
- Decreased urine output
- Altered mental status
*Post Burn Shock Phase
- 24-48 hours post injury
- Capillaries regain integrity
- Shock slowly resolves and fluid returns to the intravascular space
- Urine output increases (due to diuresis)
- BP and cardiac output begin to normalize
Physiological Responses to Burn Injury
Pulmonary
- Transient pulmonary hypertension caused by the release of vasoconstrictive mediator substances.
- Decreased oxygen tension and lung compliance.
- May be complicated by inhalation
Physiological Responses to Burn Injury
Fluid and Electrolytes
Potassium
- Initial Hyperkalemia: potassium released into the vascular space from damaged cells.
- As fluid shifts progress, potassium is leaked out of the intravascular space, leading to hypokalemia.
Sodium
- Fluid shifts lead to sodium leaking out of the intravascular space.
Physiological Responses to Burn Injury
Renal
Renal function may be impaired due to decreased perfusion.
Hemoglobin and myoglobin released by damaged cells may occlude the renal tubules leading to acute tubular necrosis.
- Most often seen in electrical injuries
- Monitor CK-MB
- Monitor urine color
Physiological Responses to Burn Injury
Gastrointestinal
Complications due to decreased nutrient absorption and decreased GI motility**
- Use of prokinetic agents and early enteral nutrition support decreases risk
Risk for abdominal compartment syndrome due to massive fluid resuscitation
Physiological Responses to Burn Injury
Metabolic
Hypermetabolism
*Begins as resuscitation is completed.
*May last up to 1-3 years post burn injury.
*Caused by inflammatory responses mediators such as catecholamines, cortisol, and glucagon.
*Produces a catabolic effect on the body
- Skeletal muscle breakdown
- Decreased protein synthesis
- Increased glucose use
- Rapid depletion of glycogen stores
*Requires significant nutrition support throughout the treatment period.
Impaired Thermoregulatory Function
*Massive body heat lost through open wounds.
- High ambient temperature must be maintained in the patient’s room and operating room.
Sepsis
*Patient is continuously at risk for infection.
*Leading cause of death in patients who survive the first 24 hours post injury**
Resuscitative Phase (Emergency Phase)
- Time
- Focus
Begins at the time of injury and continues for approximately 48 hours until the massive fluid and protein shifts have stabilized.
Primary focus is on the maintenance of the ABCs and prevention of burn shock.
Includes care in the prehospital setting, the ED, and the critical care/burn center.
Resuscitative Phase (Emergency Phase)
Prehospital Treatment
Primary Survey
The priorities of prehospital care and management are to extricate the patient safely, stop the burning process, identify life-threatening injuries, and minimize the time on scene by rapidly transporting the patient to an appropriate care facility.
*May necessitate air transport
Primary Survey: A fast, systematic assessment that prioritizes evaluation of the patient’s airway, breathing and circulatory status.
*Stop the Burning Process
- First priority of patient care: Remove the patient from the source of burning while preventing further injury.
- Extinguish flames by rolling the patient, smothering flames with a blanket or dousing with water.
- NEVER APPLY ICE OR COLD WATER: leads to further tissue damage as a result of vasoconstriction and hypothermia.
- Remove jewelry immediately.
- Scald, Tar, or Asphalt Burns: remove saturated clothing and rinse with cool water.
- Do not attempt to remove adherent tar or clothing at the scene.
- Electrical injuries: prompt removal of electrical source while protecting the rescuer.
- Chemical Injuries: wear protective barrier garments to prevent rescuer exposure; immediately remove all clothing and institute water lavage before and during transport; do not use neutralizing agents.
Resuscitative Phase (Emergency Phase)
Prehospital Primary Survey
Airway
Airway (with Cervical Spine Precautions)
*Any suspicion of inhalation injury requires immediate intervention for airway control.
*Respiratory stridor indicates airway obstruction and mandates immediate endotracheal intubation on scene**
*Patients with severe facial burns are intubated prophylactically.
- Delayed intubation may be difficult (or impossible) as edema develops.
Resuscitative Phase (Emergency Phase)
Prehospital Primary Survey
Breathing
*All patients with suspected smoke inhalation are treated at the scene with 100% humidified oxygen**
- Administered via non-rebreather mask or endotracheal tube.
- Significantly reduces the half-life of carbon monoxide.
*Monitor for clinical signs of decreasing oxygenation such as changes in respiratory rate or neurological status.
- Remember, pulse ox measurements may not be accurate**
Resuscitative Phase (Emergency Phase)
Prehospital Primary Survey
Circulation
*Remove all clothing and jewelry to prevent constriction and ischemia secondary to edema.
*Insert 2 large-bore IV catheters
- Initiate Lactated Ringers (LR) solution at 500 mL/hr until fluid requirements are calculated.
*Monitor for signs of hypovolemia.
- Hypovolemic shock rarely occurs in the early pre-hospital phase. Suspect associated internal injury if evidence of shock is present at this time.
*Cover the patient with a clean dry sheet and blankets to prevent hypothermia (due to loss of skin thermoregulation) and further wound contamination.
Resuscitative Phase (Emergency Phase)
Secondary Survey
*Rapid head-to-toe assessment to rule out any additional trauma.
*In patients with an injury mechanism suggestive of spinal injury, apply standard precautions (cervical collar, immobilization).
*Obtain an accurate history
*Events that led to the burn injury
- Time of injury
- Source of burns
- Events leading to the injury
*Brief medical history
- Allergies
- Current medical problems
- Medications
- Past surgical procedures and /or trauma
- Time of last meal
- History of tetanus immunization
*Provide pain relief/administer pain medication.
- Short acting IV opioid (i.e., Morphine)
- Do not give IM or PO medications.
Patients with major burn injury require complex care and the expertise of a specially trained multidisciplinary team.
Guidelines for Burn Center Referral/Transfer**
- Partial thickness burns 10% of total body surface area
- Full thickness burns
- Burns involving the face, hands, feet, genitalia, perineum, or major joints
- Chemical burns
- Electrical burns
- Inhalation injury
- Pre-existing medical disorders
- Associated trauma
- Hospital without qualified personnel or equipment to care for burn injured children
- Patients requiring special social, emotion, or rehabilitative intervention
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
Airway
*Issues related to tracheal edema may occur early or may not be apparent until after fluid resuscitation is initiated.
*Patients not already intubated:
- Frequently monitor for signs of airway edema
- Anticipate assisting with early intubation.
*If the patient is intubated:
- Assess for accurate tube position.
- Securely tie the endotracheal tube in place
- Protection of the airway is crucial: It may be impossible to reintubate the patient if the airway becomes dislodged!
- Elevate the head of the bed to reduce facial and airway edema.
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
Breathing
*Assess for impaired gas exchange.
*Evaluate breath sounds, characteristics of respirations, work of breathing, sputum color and consistency and symmetry of chest wall expansion.
*Obtain ABG on all intubated patients.
*Monitor patients with circumferential full-thickness burns of the thorax for inadequate ventilation.
*Turn patient every 2 hours to promote skin integrity and mobilize secretions.
*Encourage coughing, deep breathing, and suctioning as needed. Early ambulation when possible.
*Lung-protective ventilation strategies for intubated patients
- Lower tidal volumes and plateau pressure
*Nebulization therapy with aerosolized heparin, B2-adrenergic blockers (albuterol), and N-acetylcysteine (Mucomyst) may be beneficial adjuncts to assist with opening the airways and reducing inflammatory effects.
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
If inhalation injury suspected:
If cyanide poisoning:
*Measure COHgb if inhalation injury is expected.
- Administer 100% humidified oxygen until COHgb levels are determined.
- Once COHgb levels normalize (<10%), wean oxygen as tolerated.
If cyanide poisoning is expected, empirical treatment with antidote is indicated.
- Hydroxocobalamin: Red discoloration of urine and body fluids is an expected side effect**
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
*Monitor patients with circumferential full-thickness burns of the thorax for inadequate ventilation.
If inadequate ventilation:
- Signs
- Treatment
Early Signs:
- Increased peak inspiratory pressure and decreased tidal volumes
Rule out other causes of inadequate ventilation
- Pneumothorax, hemothorax, tension pneumothorax
Patient may require immediate chest wall escharotomy.
- An incision is performed through the full thickness burn to reduce constriction caused by eschar.
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
Circulation: Fluid Resuscitation and Calculation
*Formal fluid resuscitation is instituted in patients with burns greater than 20% TBSA
*Fluid Resuscitation Calculation
Advanced Burn Life Support Guidelines (Modified Parkland Formula)**
Based on the following:
- Age
- Weight in kilograms
- %TBSA burned
- Presence of electrical injury
Total 24-hour volume calculation
- Adults: 2 mL x weight (kg) x %TBSA
- Children: 3 x weight x %TBSA
- Electrical Injury: 4 x weight x %TBSA
*Half of the volume is given in the first 8 hours**
*Measured from time of injury, NOT time fluids are started**
*Remaining volume given over the next 16 hours**
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
Circulation: End Point Monitoring
*Goal of burn resuscitation: maintain tissue perfusion and organ function while preventing the complications of inadequate or excessive fluid therapy**
*Fluid infusion rates are titrated to physiological end points.
- Urine output: ensure UOP of greater than 0.5 mL/kg/hr (30-50 mL/hr)
- Other endpoints that may be monitored: blood pressure, cardiac preload, systemic vascular resistance, and stroke volume.
*Systolic Blood Pressure: Greater than 100 mm Hg
*Heart Rate: Less than 120 bpm
*Central Venous Pressure: 5-10 mm Hg
*Pulmonary: Lung sounds clear, pH within normal range
*Gastrointestinal: Abdomen soft, non-tender, No nausea, vomiting or ileus
*Level of Consciousness: Clear, alert and oriented
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Primary Survey
Circulation: Peripheral Circulation
Special attention should be given to full-thickness burns of the extremities that are circumferential due to concern for impaired blood flow.
*Elevate extremities to reduce edema.
*Perform active or passive ROM exercises every hour to increase venous return and minimize edema.
*Assess pain, sensation, and peripheral pulses every hour.
*Monitor for Compartment Syndrome
Compartment Syndrome
Clinical Indicators
Treatment
Clinical Indicators:
- Presence of circumferential deep partial- or full thickness extremity burns
- Electrical burns
- Pain: increasing, greater than expected, or out of proportion to the injury
- Increasing edema: muscle compartments tense on palpation or asymmetrical in size
- Altered sensation
- Late signs: pallor, poor capillary refill, absent distal pulses
Treatment
- Prepare for escharotomy to relieve pressure and restore circulation.
- Fasciotomy (incision through the fascia) may be indicated for deep electrical burns or severe muscle damage.
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Secondary Survey
Includes a head-to-toe assessment, complete history, reassessment of interventions implemented during the primary survey, and vital signs (at least hourly)
Assess indices of essential organ function hourly to evaluate resuscitation and prevent complications.
- Blood pressure
- Heart rate
- Temperature
- Peripheral pulses
- Urinary output
Closely monitor pain levels and intervene appropriately.
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Secondary Survey
Circulation: Monitor (Vital signs, Risks)
*Baseline heart rate may be between 100-120 beats/min due to increased metabolism.
*Decreasing blood pressure is a LATE sign of inadequate perfusion.
*Blood pressure readings may be altered due to peripheral tissue edema and arteriospasms.
*Pain, anxiety, and fear may also alter vital signs.
*Patients with cardiopulmonary disease, elderly patients and those with unexplained large fluid volume requirements may need pulmonary artery catheters for monitoring.
- Low right atrial pressure and low pulmonary artery occlusion pressure indicates hypovolemia.
*CONSIDER THE ENTIRE PATIENT AND ASSESS TRENDS rather than focus on a specific value.
*High risk for DVT and/or PE
- Due to local thermal injury, venous stasis, hypercoagulability, and immobility
- Clinical findings of DBT may be absent or obscured.
- Closely monitor for sudden respiratory deterioration, which may indicate PE.
- Prophylactic Measures: SCDs, early mobility
- Medications: Enoxaparin (Lovenox)
Resuscitative Phase (Emergency Phase)
Emergency Department and Critical Care Burn Center
Secondary Survey
Neurological System
*Even severely burned patients are initially awake, alert, and oriented
- If patient presents with decreased LOC, suspect other injuries (i.e., head injury CO or cyanide poisoning, intoxication)
*Neuro checks should be performed hourly.
- Increased agitation or confusion and decreasing LOC may indicate hypovolemia and/or hypoxemia.
*Elevated the head of bed to prevent facial swelling (unless contraindicated).
