10.2 Major Burns: Rule of Nines, Parkland Fluid Resuscitation & Wound Care

10.2 Major Burns: Rule of Nines, Parkland Fluid Resuscitation & Wound Care

Quick Answer: The Wallace Rule of Nines calculates adult Total Body Surface Area (TBSA) burned (Head 9%, Each Arm 9%, Anterior Torso 18%, Posterior Torso 18%, Each Leg 18%, Perineum 1%). Inhalation injury (facial burns, singed nasal hairs, carbonaceous sputum, hoarseness) requires immediate intubation before progressive glottic edema causes complete obstruction. The Parkland (Baxter) formula provides IV Lactated Ringer's over the first 24 hours (4 mL x kg x % TBSA), with 50% delivered during the first 8 hours calculated from the time of the burn injury (not arrival time!) and 50% over the subsequent 16 hours. Resuscitation adequacy is titrated to hourly urine output: 0.5–1.0 mL/kg/hr in adults, and 75–100 mL/hr in electrical burns to clear myoglobinuria. Circumferential burns compromise distal circulation or ventilatory excursion, necessitating emergency escharotomy.

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Burn Etiology & Mechanisms of Injury

Burns represent severe tissue trauma resulting from energy transfer to the skin and underlying structures. The pathophysiological impact ranges from localized epidermal damage to profound systemic "burn shock" characterized by massive capillary leak, intravascular fluid depletion, and hypermetabolism.

1. Thermal Burns: The most common etiology across Ghana, including flame burns from domestic cooking fires, kerosene lantern explosions, scalding from hot water or boiling palm oil, and direct contact with heated metals. Thermal destruction follows Jackson's Burn Zones:
   • Zone of Coagulation: The central zone of direct cellular death and protein coagulation; tissue is necrotic and irreversible.
   • Zone of Stasis: The intermediate zone characterized by compromised microvascular perfusion, cellular injury, and ischemia. This tissue is potentially salvageable with prompt, aggressive fluid resuscitation; poor resuscitation converts it to non-viable coagulated eschar.
   • Zone of Hyperemia: The outermost perimeter exhibiting increased blood flow from inflammatory vasodilation; typically recovers spontaneously within 7–10 days.
2. Chemical Burns: Triggered by exposure to caustic substances. Acids (e.g., sulfuric acid, battery acid) produce coagulative necrosis, forming a leathery eschar that self-limits deeper penetration. Alkalis (e.g., caustic soda/lye used in local soap manufacturing, ammonia) cause liquefactive necrosis, which saponifies cell membrane lipids, dissolves tissue proteins, and allows unrelenting, deep penetration into subcutaneous structures. Emergency management requires immediate removal of contaminated clothing and continuous, high-volume irrigation with running tap water for at least 20–30 minutes. Chemical neutralizing agents must never be applied, as the exothermic reaction produces secondary thermal burns.
3. Electrical Burns: Manifest as an "iceberg effect". Small entry and exit skin wounds conceal massive underlying tissue destruction along the path of current conduction. High-resistance tissues (bone, fat) generate significant heat, causing coagulation necrosis of adjacent deep muscle, blood vessels, and nerves. Complications include life-threatening cardiac dysrhythmias (ventricular fibrillation, asystole), acute compartment syndrome, and extensive rhabdomyolysis. Damaged muscle cells release massive amounts of myoglobin, which precipitates within renal tubules, causing pigment-induced acute tubular necrosis (ATN) and renal failure.
4. Radiation Burns: Caused by prolonged ultraviolet (UV) radiation or ionizing industrial/medical radiation, damaging cellular DNA and epidermal basal layers.

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Burn Depth Classification: Pathophysiology and Clinical Presentation

Accurate depth classification is critical for calculating fluid resuscitation requirements, planning surgical wound closure, and establishing functional prognosis.

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Total Body Surface Area (TBSA) Assessment

Total Body Surface Area (TBSA) calculation guides fluid resuscitation volume. Only partial-thickness (second-degree) and full-thickness (third-degree) burns are included in the TBSA calculation. Superficial first-degree erythema (e.g., simple sunburn) is strictly excluded because the dermal microcirculation remains intact without capillary leak.

Wallace Rule of Nines (Adults)

The Rule of Nines divides the adult human body into anatomical regions representing 9% (or multiples of 9%) of total body surface area:

• Head and Neck: 9% (4.5% anterior face/neck, 4.5% posterior scalp/neck)
• Anterior Torso: 18% (chest 9%, abdomen 9%)
• Posterior Torso: 18% (upper back 9%, lower back/buttocks 9%)
• Right Upper Extremity (Entire Arm): 9% (4.5% anterior, 4.5% posterior)
• Left Upper Extremity (Entire Arm): 9% (4.5% anterior, 4.5% posterior)
• Right Lower Extremity (Entire Leg): 18% (9% anterior, 9% posterior)
• Left Lower Extremity (Entire Leg): 18% (9% anterior, 9% posterior)
• Perineum and External Genitalia: 1%
• Total Body Surface Area: 100%

The Palmar Surface Method & Pediatric Adjustments

• Palmar Surface Method: The patient's palm, including the fingers held flat together, represents approximately 1% of the patient's own TBSA. This clinical tool is used to estimate scattered, patchy burn areas or small burns (<15% TBSA).
• Pediatric Lund-Browder Modifications: In infants and young children, body proportions differ significantly from adults. An infant's head is proportionately larger and lower extremities smaller:
  • Infant head represents 18% TBSA (compared to 9% in adults);
  • Each infant leg represents 14% TBSA (compared to 18% in adults);
  • For each year of age from 1 to 10 years, subtract 1% from the head and add 0.5% to each leg until adult proportions are reached.

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Inhalation Injury: Pathophysiology, Recognition, and Airway Protection

Inhalation injury increases mortality by up to 20–40% in burn patients and is the leading cause of early death in fires. It occurs when a victim is trapped in an enclosed, smoke-filled space, exposed to superheated gases, or injured in an explosion.

                                [INHALATION INJURY SUSPECTED]
                                               |
       +---------------------------------------+---------------------------------------+
       |                                                                               |
       v                                                                               v
[CLINICAL RED FLAGS]                                                        [SYSTEMIC ASPHYXIANTS]
- Facial / neck burns                                                        - Carbon Monoxide (CO):
- Singed nasal hairs & eyebrows                                                * Falsely normal SpO2
- Carbonaceous soot in sputum ("black spit")                                   * Treat with 100% O2
- Brassy cough, hoarseness, stridor                                         - Hydrogen Cyanide:
- Pharyngeal edema & erythema                                                  * Hydroxocobalamin
       |                                                                               |
       +---------------------------------------+---------------------------------------+
                                               |
                                               v
               [IMMEDIATE PREEMPTIVE ENDOTRACHEAL INTUBATION]
               *Do not wait for stridor, desaturation, or ABG deterioration!* 

Clinical Red Flags of Inhalation Injury

• History of fire in an enclosed or trapped space;
• Deep burns involving the face, lips, nose, or neck;
• Singed nasal vibrissae (hairs), eyebrows, and eyelashes;
• Carbonaceous soot deposits in the oral cavity, posterior pharynx, or sputum ("carbonaceous sputum");
• Brassy cough, voice changes, or progressive hoarseness;
• Inspiratory stridor, tachypnea, wheezing, and dyspnea;
• Carboxyhemoglobin level >10% in non-smokers or >15% in smokers.

Emergency Nursing Interventions

Superheated steam and toxic smoke chemicals cause rapid, progressive supraglottic edema that peaks between 12 and 24 hours post-injury. Do not wait for arterial blood gas deterioration, hypoxemia, or audible stridor to develop. Stridor indicates >85% airway narrowing. When clinical red flags are identified, prepare for immediate preemptive endotracheal intubation before glottic and laryngeal edema obliterates anatomical landmarks. Delaying intubation risks complete airway occlusion, necessitating emergency surgical cricothyroidotomy.

Administer 100% high-flow oxygen via a non-rebreather mask immediately. In Carbon Monoxide (CO) poisoning, pulse oximetry (SpO2) is deceptively normal because conventional pulse oximeters cannot distinguish carboxyhemoglobin from oxyhemoglobin. High-flow 100% oxygen reduces the elimination half-life of carboxyhemoglobin from 320 minutes (on room air) to approximately 80 minutes.

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Fluid Resuscitation: The Parkland (Baxter) Formula

Extensive thermal trauma causes systemic microvascular hyperpermeability. Intravascular plasma proteins, electrolytes, and water extravasate massively into the interstitial space across both burned and unburned tissues. This fluid shift produces profound hypovolemic, hemoconcentrated "burn shock" accompanied by cellular edema.

Formal fluid resuscitation is mandatory for all adult patients with partial- and full-thickness burns exceeding 20% TBSA (or >=10% TBSA in children and older adults).

The Parkland Formula Equation

$\text{Total 24-Hour IV Fluid Volume (mL)} = 4 \text{ mL} \times \text{Weight (kg)} \times \% \text{TBSA (2nd and 3rd degree)}$

• Resuscitation Crystalloid: Ringer's Lactate (Hartmann's Solution) is the preferred crystalloid because its composition and physiological buffer (metabolized to bicarbonate by the liver) match human extracellular fluid. Normal saline (0.9% NaCl) must be avoided in large volumes because its high chloride concentration (154 mEq/L) induces severe hyperchloremic metabolic acidosis.

The 24-Hour Infusion Schedule

Resuscitation fluid is delivered across two distinct phases based on capillary leak dynamics:

• First 8 Hours: Administer 50% (one-half) of the total calculated volume within the first 8 hours CALCULATED FROM THE EXACT TIME OF THE BURN INJURY, not the time of hospital arrival.
• Remaining 16 Hours: Administer the remaining 50% (one-half) of the total volume evenly over the subsequent 16 hours.

[!IMPORTANT] Exam Alert: The "Time of Burn" Rule Licensure exams test the delay between injury and hospital presentation. If a 70 kg patient with a 40% TBSA burn was injured at 06:00 but arrives at the emergency unit at 08:00 (2 hours post-injury), the first half of the calculated fluid must be infused within the remaining 6 hours of the initial 8-hour window (by 14:00), requiring an increased hourly rate!

Step-by-Step Calculation Example

• Patient Profile: 70 kg adult with 40% TBSA deep partial- and full-thickness burns, injured at 10:00, arrives at emergency department at 12:00 (2 hours elapsed).
• Total 24-Hour Fluid: $4 \text{ mL} \times 70 \text{ kg} \times 40 = 11,200 \text{ mL}$ of Ringer's Lactate.
• First 8 Hours (from 10:00 to 18:00): $50% \text{ of } 11,200 \text{ mL} = 5,600 \text{ mL}$. Because 2 hours have elapsed, this 5,600 mL must be infused over the remaining 6 hours: $\frac{5,600 \text{ mL}}{6 \text{ hours}} \approx 933 \text{ mL/hr}$.
• Subsequent 16 Hours (from 18:00 to 10:00 next day): Remaining $5,600 \text{ mL}$ over 16 hours: $\frac{5,600 \text{ mL}}{16 \text{ hours}} = 350 \text{ mL/hr}$.

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Monitoring Resuscitation Adequacy: Urine Output Benchmarks

The Parkland formula is only a starting estimate. Fluid administration must be titrated hourly against objective clinical markers of end-organ perfusion.

An indwelling urinary catheter connected to an hourly urometer must be placed immediately in all major burn patients. Hourly urine output is the gold standard indicator of systemic perfusion adequacy:

1. Adult Thermal Burns: Maintain urine output at 0.5 to 1.0 mL/kg/hr (approximately 30 to 50 mL/hr in average adults). If urine output falls below 30 mL/hr, increase the hourly IV fluid infusion rate by 20–25%. If urine output consistently exceeds 50–70 mL/hr, decrease the rate to prevent over-resuscitation ("fluid creep"), which can lead to pulmonary edema and abdominal compartment syndrome.
2. Pediatric Thermal Burns (<30 kg): Maintain urine output at 1.0 to 1.5 mL/kg/hr.
3. High-Voltage Electrical Burns / Crush Injury: Maintain urine output at 75 to 100 mL/hr (or 1.5–2.0 mL/kg/hr in children) until the urine is visibly clear of dark pigmentation. Rhabdomyolysis releases massive amounts of myoglobin and hemoglobin into the circulation; maintaining high tubular flow washes out these nephrotoxic pigments. Administer intravenous sodium bicarbonate (to alkalinize urine above pH 6.5, increasing myoglobin solubility) and IV mannitol (osmotic diuresis) as ordered.

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Burn Wound Care, Topical Chemotherapy, and Surgical Decompression

Acute Wound Care Principles

• Cooling: Cool fresh thermal burns with cool running water (about 15–20°C) for 20 minutes, as soon as possible and up to 3 hours after injury, while keeping the rest of the patient warm. Never apply ice, iced water, or freezing compresses. Ice causes intense dermal vasoconstriction, ischemia, and hypothermia, converting partial-thickness burns into full-thickness necrosis.
• Debridement: Clean wounds under aseptic conditions with mild antiseptic soap or sterile saline. Large, tense, fluid-filled blisters over joints should be de-roofed or aspirated under sterile technique to remove inflammatory mediators, while small, intact blisters on the palms or soles may be preserved.

Topical Antimicrobial Agents

Because the burned microvasculature is thrombosed, systemic prophylactic antibiotics cannot penetrate the avascular eschar to reach the colonizing bacteria; systemic antibiotics simply select for resistant pathogens. Burn wound care relies on topical antimicrobials:

• Silver Sulfadiazine (Silvadene 1%): Standard broad-spectrum topical agent active against Gram-negative bacteria (Pseudomonas aeruginosa), Gram-positive organisms, and Candida albicans. Application is painless. Adverse effect: Transient, self-limiting leukopenia (neutrophil count drops); Contraindications: Sulfa allergy, pregnancy near term, and infants under 2 months of age (due to the risk of kernicterus).
• Silver Nitrate (0.5% aqueous solution): Effective topical antimicrobial. Disadvantages: Stains skin, dressings, and hospital bed linens black; leaches electrolytes across open wounds, causing severe hypochloremia and hyponatremia.
• Mafenide Acetate (Sulfamylon 8.5% cream): Highly diffusible; penetrates deeply through thick, avascular eschar and cartilage (preferred for burns of the ears and nose). Disadvantages: Application is painful; acts as a carbonic anhydrase inhibitor, causing systemic metabolic acidosis and compensatory hyperventilation.

Closed vs. Open Wound Dressings

• Closed Method: Topical antimicrobial applied and covered with non-adherent sterile fine-mesh gauze, followed by thick absorbent cotton pads and elastic roller bandages. Protects the wound from environmental contamination, absorbs exudate, reduces evaporative heat loss, and splints joints in functional positions.
• Open (Exposure) Method: Topical agent applied directly to the wound and left uncovered. Used exclusively for burns to the face, neck, and perineum, where bulky dressings are impractical and predispose to maceration.

Surgical Decompression: Emergency Escharotomy

Full-thickness burns produce a rigid, leathery, inelastic coagulated tissue layer termed eschar. During the initial 24–48 hours of resuscitation, interstitial edema accumulates beneath the unyielding eschar, elevating sub-eschar tissue pressure above capillary perfusion pressure (similar to compartment syndrome):

• Circumferential Extremity Burns: Elevated pressure compresses digital and radial/tibial arteries and veins, causing ischemic gangrene and peripheral nerve death. Clinical indicators: progressive loss of distal palpable pulses, cyanosis, delayed capillary refill, paresthesia, and cool digits.
• Circumferential Thoracic Burns: Constrictive chest eschar prevents mechanical thoracic expansion during ventilation, leading to hypoventilation, hypercapnia, and elevated peak airway pressures on mechanical ventilators.
• Escharotomy Technique: An emergency bedside surgical incision through the full thickness of the eschar down to viable subcutaneous tissue. The incision is made along the mid-medial and mid-lateral axes of the limbs, or in a "shield/grid" pattern across the anterior chest wall. Full-thickness eschar is insensate, but the incision often reaches viable, sensitive tissue, so analgesia or sedation is still given; bleeding is controlled with electrocautery or firm gauze packing.

Prevention of Curling's Stress Ulcer

Extensive thermal injuries (>20% TBSA) induce severe splanchnic vasoconstriction, leading to gastric and duodenal mucosal ischemia and hypersecretion of gastric acid. This causes acute mucosal erosion and life-threatening gastrointestinal hemorrhage, known as Curling's ulcer. Management involves early enteral tube feeding (initiated within 6–12 hours post-injury to maintain splanchnic blood flow and mucosal barrier integrity) alongside intravenous Proton Pump Inhibitors (PPIs) or H2-receptor antagonists.