Before We Start
Burns — depth, extent, and the fluid resuscitation that saves the first 48 hours
Burn injuries are among the most physiologically devastating traumas a human being can sustain. The skin — the body's largest organ — is destroyed. Fluid, protein, and heat pour out through the wound. Smoke inhalation damages the airways. Infection threatens the exposed tissue. And a systemic inflammatory response disrupts nearly every organ system.
For nursing, burn care requires mastering three things: accurately assessing burn depth and extent (which determines severity and treatment), understanding the fluid resuscitation formula that prevents distributive shock in the first 48 hours, and recognizing the inhalation injury that is the leading cause of death in burn patients.
💡 Why Burns Kill — The Three Phases
First 48 hours (Emergent phase): Massive fluid shifts — capillaries become leaky, plasma pours out of the vascular space into tissues. Without aggressive IV fluid resuscitation, the patient goes into distributive (hypovolemic-like) shock and dies.
48 hours to 3 weeks (Acute/Fluid remobilization phase): Capillary integrity restores, fluid shifts back into the vascular space. Risk of fluid overload and pulmonary edema. Infection risk is highest.
Weeks to months (Rehabilitation phase): Wound healing, skin grafting, scar management, functional rehabilitation.
Burn Depth Classification
Superficial to full thickness — depth determines pain, appearance, and treatment
Superficial (First Degree)
Epidermis only — red, painful, no blisters — sunburn
Only the epidermis (outermost skin layer) is involved. The dermis and deeper structures are intact.
Appearance: Red, dry, no blisters. Blanches with pressure (blood vessels intact). Painful.
Example: Sunburn, brief flash burn.
Treatment: Analgesics, topical aloe or moisturizer, cool water. Heals in 3–5 days without scarring.
NOT included in TBSA calculation — first-degree burns are not counted when calculating burn extent for fluid resuscitation formulas.
Partial Thickness (Second Degree)
Into the dermis — blisters, extremely painful, moist and red
The epidermis and part of the dermis are destroyed. This is the most painful burn type because the nerve endings in the dermis are exposed and intact — every air movement causes pain.
Superficial partial thickness: Into superficial dermis. Blisters, moist, red, extremely painful. Heals in 14–21 days with minimal scarring.
Deep partial thickness: Into deep dermis. Pale or mottled appearance, may or may not be painful (some nerve endings destroyed), moist or dry. May require skin grafting. Heals in 21–35 days with significant scarring.
The blister rule: Do NOT rupture blisters — intact blisters protect the underlying tissue from infection. If a blister ruptures spontaneously, clean the area and apply appropriate wound dressing.
💊 "Second degree = the most painful." The preserved nerve endings in the dermis make partial thickness burns exquisitely sensitive. This is the burn category that requires the most aggressive pain management — adequate analgesia before wound care is essential and humane.
Full Thickness (Third Degree)
Through the entire dermis — leathery, painless, requires grafting
Both the epidermis and full dermis are destroyed. Nerve endings, hair follicles, and sweat glands are gone. The tissue cannot regenerate on its own — skin grafting is required.
Appearance: Leathery, waxy, dry. May be white, brown, or black (charred). Does NOT blanch with pressure. PAINLESS — because nerve endings are destroyed.
The painless paradox: A full-thickness burn that does not hurt is often more concerning than a partial thickness burn that is agonizingly painful. The pain correlates with preserved sensory function — no pain often means more severe destruction.
Fourth degree burns: Some classification systems include fourth degree — burns extending into muscle, bone, or tendon. Seen in prolonged flame exposure, electrical burns. Typically requires amputation.
💊 "Leathery and painless = full thickness = needs grafting." When a nurse assesses a burn area and the patient reports no sensation to touch while the tissue looks leathery or charred — that is full thickness. These patients still have intact sensation in surrounding areas and need aggressive pain management for those regions.
Burn Extent — Rule of Nines
Calculating TBSA to guide fluid resuscitation
Rule of Nines
Each body region = 9% of total body surface area (TBSA)
The Rule of Nines divides the body into regions, each representing 9% of total body surface area (TBSA). Used to calculate the extent of burns for fluid resuscitation formulas:
Head and neck: 9%
Each arm: 9% (both arms = 18%)
Anterior trunk: 18% (chest 9% + abdomen 9%)
Posterior trunk: 18% (upper back 9% + lower back 9%)
Each leg: 18% (both legs = 36%) — front 9% + back 9%
Perineum/genitalia: 1%
Total: 100%
For small or irregular burns: The palm of the patient's hand (excluding fingers) equals approximately 1% TBSA — useful for estimating irregular burn patterns.
In children: The head is proportionally larger (18%) and the legs are proportionally smaller. The Lund-Browder chart is more accurate for pediatric burn assessment.
Remember: first-degree burns are NOT included in TBSA calculations.
💊 "Quick TBSA test: burns to entire right arm + anterior chest = 9% + 18% = 27% TBSA." Practice calculating TBSA — NCLEX frequently gives a burn description and asks what percentage is affected. Add up the regions from the Rule of Nines. Only include partial and full thickness areas.
Fluid Resuscitation
The Parkland Formula — how much fluid, how fast, in what order
Parkland Formula
4mL × kg × %TBSA = total fluid for the first 24 hours
The Parkland Formula calculates the IV fluid volume needed in the first 24 hours after a burn injury to replace the massive fluid losses into tissues:
Formula: 4 mL × Weight (kg) × %TBSA burned = Total fluid (mL) in 24 hours
Fluid type: Lactated Ringer's (LR) — preferred because it most closely resembles the electrolyte composition of the fluid being lost into the burn wound. Normal saline in large volumes causes hyperchloremic metabolic acidosis.
The time-critical delivery schedule:
• First 8 hours: give HALF the total calculated volume
• Next 16 hours: give the other HALF
• Critical detail: the 8 hours is counted from the TIME OF INJURY, not from hospital arrival
Worked example: 70kg patient with 40% TBSA burns:
4 × 70 × 40 = 11,200 mL total in 24 hours
First 8 hours from injury: 5,600 mL (700 mL/hour)
Next 16 hours: 5,600 mL (350 mL/hour)
Monitoring adequacy: Urine output 0.5–1 mL/kg/hour is the target — the best indicator of adequate resuscitation. Urine output reflects renal perfusion which reflects cardiac output.
💊 "8 hours from INJURY, not from arrival." A patient who was burned at 2pm and arrives in the ED at 4pm has already used 2 of their first 8 hours. The first half of fluids must be given in the remaining 6 hours — meaning the rate is faster than if resuscitation had started at the time of injury. Always clarify the time of injury, not time of arrival.
Inhalation Injury
The leading cause of death in burn patients — airway assessment is priority one
Inhalation Injury Assessment
Signs that the airway is at risk — and why early intubation saves lives
Inhalation injury from smoke, steam, or toxic gases causes more burn fatalities than the skin burns themselves. The airway can swell shut within hours of exposure — waiting is fatal.
Signs of inhalation injury:
• Singed nasal hairs or eyebrows
• Carbonaceous (black, sooty) sputum
• Hoarseness, stridor, or change in voice quality
• Facial burns
• History of being in an enclosed space with fire or smoke
• Oropharyngeal erythema or edema on inspection
Why early intubation: Airway edema from inhalation injury progressively worsens over the first 24–48 hours. A patient who is breathing adequately on arrival may have a completely swollen airway 6 hours later. Early intubation while the airway is still accessible is far preferable to emergency intubation through a massively edematous, distorted airway.
Carbon monoxide poisoning: CO binds to hemoglobin with 200× the affinity of oxygen. Pulse oximetry reads FALSELY NORMAL because the oximeter cannot distinguish between oxyhemoglobin and carboxyhemoglobin. A patient with CO poisoning may have SpO2 of 99% and be severely hypoxic. Treatment: 100% oxygen via non-rebreather mask — displaces CO from hemoglobin. Diagnosis: arterial blood gas with co-oximetry measuring actual carboxyhemoglobin level.
💊 "Pulse oximetry lies in CO poisoning." A patient pulled from a house fire with SpO2 99% on the monitor is not necessarily well-oxygenated. Pulse oximetry cannot detect carboxyhemoglobin. Give 100% O2 regardless of pulse oximetry reading, and confirm with ABG co-oximetry. This is one of the most important and commonly missed facts in burn care.
🏥 Clinical Scenario — Major Burn Admission
Mr. Petrov, 52 years old, 78kg, was in a house fire. He was found in the basement, unconscious. Burns are present. Time of injury: 10pm. He arrives in the ED at 10:45pm.
Airway
Inhalation injury assessment: Singed eyebrows and nasal hair. Black carbonaceous sputum. Voice is hoarse. Oropharynx erythematous. History of enclosed space. High-risk inhalation injury. Anesthesia called immediately for early intubation. 100% O2 via NRB until intubated. ABG with co-oximetry ordered — carboxyhemoglobin 24% (toxic).
TBSA
Burn assessment: Entire right arm (9%) — partial thickness, blistered, painful. Anterior trunk (18%) — mixture of partial and full thickness. Both legs (36%) — partial thickness anterior only (18%). First-degree erythema on face — NOT counted. Total TBSA: 9 + 18 + 18 = 45% TBSA.
Parkland
Fluid calculation: 4 × 78 × 45 = 14,040 mL total in 24 hours.
First 8 hours (from 10pm injury): 7,020 mL = 878 mL/hour. But it is now 10:45pm — 45 minutes have passed. Remaining time in first 8 hours: 7 hours 15 minutes. Rate adjusted: 7,020 ÷ 7.25 hours = 968 mL/hour for first portion. LR hung wide. Foley placed — urine output target 39–78 mL/hour (0.5–1 mL/kg/hr).
Monitor
Ongoing assessment: Urine output at 1 hour: 52 mL — adequate (within 39–78 mL target). BP 108/72. HR 118 — tachycardia expected from fluid shifts and pain. Burned extremities elevated above heart level to reduce edema. No circumferential burns noted — if present, would monitor for compartment syndrome requiring escharotomy. Wound care deferred until patient is stabilized — clean cover dressings placed.
📌 NCLEX Application
Burns are tested heavily on NCLEX — TBSA calculation, Parkland formula, and inhalation injury:
TBSA calculation: "A patient has burns to the entire head (9%), right arm (9%), and anterior trunk (18%). What is the TBSA?" → 36%. First-degree burns are not counted.
Parkland formula: "A 70kg patient has 30% TBSA burns. Using the Parkland formula, how much fluid is given in the first 8 hours?" → 4 × 70 × 30 = 8,400 mL total. Half in first 8 hours = 4,200 mL = 525 mL/hour.
Fluid timing: "The 8-hour window in the Parkland formula begins at what time?" → Time of injury — not time of hospital arrival.
CO poisoning: "A patient rescued from a fire has SpO2 of 98%. What does the nurse recognize?" → Pulse oximetry is falsely normal in CO poisoning — give 100% O2 via NRB and order ABG with co-oximetry. Do not rely on SpO2 in suspected CO poisoning.
Pain in burns: "Which burn type is most painful?" → Partial thickness (second degree) — nerve endings are exposed but intact. Full thickness (third degree) is paradoxically less painful because nerve endings are destroyed.
⚠️ The Trap — Starting the Parkland Clock at Hospital Arrival
A patient was burned at 2pm and arrives at the ED at 5pm. The nurse calculates the Parkland formula correctly and divides the first-half fluid over 8 hours starting from 5pm (hospital arrival), planning to give the first half by 1am.
What is wrong: The 8-hour window begins at the TIME OF INJURY — 2pm — not at hospital arrival. By the time the patient arrives at 5pm, 3 hours have already elapsed. The first half of fluids must be delivered in the remaining 5 hours (by 10pm), not by 1am.
The consequence: Under-resuscitating in the first 8 hours from injury allows distributive shock to develop from the massive capillary leak. The patient develops hypotension, acute kidney injury, and potentially multi-organ failure — all preventable with adequate early resuscitation.
The rule: Always ask: "What time did the injury occur?" Calculate from THAT time, regardless of when the patient arrives. If the patient arrives 4 hours post-injury, the first-half fluids must be compressed into 4 hours, not 8.
✓ Quick Self-Test
Answer before checking:
1. Using the Rule of Nines, calculate TBSA for burns to both legs (anterior only) and the posterior trunk.
2. Apply the Parkland formula for an 80kg patient with 25% TBSA burns. How much fluid in the first 8 hours?
3. Why is pulse oximetry unreliable in carbon monoxide poisoning?
4. Which burn depth is paradoxically painless and why?
5. What urine output target indicates adequate fluid resuscitation in a burn patient?
Answers:
1. Both legs anterior = 9% + 9% = 18%. Posterior trunk = 18%. Total TBSA = 36%.
2. Parkland: 4 × 80 × 25 = 8,000 mL total in 24 hours. First 8 hours: 4,000 mL = 500 mL/hour. Next 16 hours: 4,000 mL = 250 mL/hour. Fluid type: Lactated Ringer's.
3. Pulse oximetry measures the percentage of hemoglobin bound to something — it cannot distinguish between oxyhemoglobin (O2 bound) and carboxyhemoglobin (CO bound). A patient with high carboxyhemoglobin reads falsely normal on SpO2. ABG with co-oximetry is needed to identify true CO poisoning.
4. Full thickness (third degree) burns are painless because the nerve endings in the dermis have been completely destroyed. No nerve endings = no pain signal. This paradox makes full thickness burns less painful than partial thickness burns, which have exposed, intact nerve endings.
5. 0.5–1 mL/kg/hour — or approximately 30–50 mL/hour in most adults. Urine output is the best clinical indicator of adequate resuscitation because it reflects renal perfusion and therefore cardiac output.
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DIC — Disseminated Intravascular Coagulation
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