20.3 ENT/Shared Airway, Extrathoracic Procedures & Trauma/Burn Resuscitation
Key Takeaways
- Surgical airway fires require the classic triad of Fuel, Oxidizer, and Ignition Source; during airway laser surgery, oxidizers must be minimized (FiO₂ ≤ 30%, avoid N₂O entirely), laser-safe dual-cuffed ETTs must be used with saline/methylene blue cuff inflation, and immediate fire response mandates extubating the burning tube, extinguishing with saline, and discontinuing gas flows.
- Post-tonsillectomy bleeding is a critical pediatric emergency presenting with hidden hypovolemia and a stomach filled with swallowed blood; management requires aggressive intravenous volume resuscitation before induction, two functional suction setups, and a rapid sequence induction (RSI) followed by mandatory stomach evacuation.
- Tumescent liposuction utilizes dilute lidocaine (0.05-0.1%) with epinephrine up to maximum doses of 35 to 55 mg/kg; intense local vasoconstriction delays peak plasma lidocaine concentrations to 12 to 14 hours postoperatively, mandating extended surveillance for Local Anesthetic Systemic Toxicity (LAST).
- Trauma resuscitation adheres to Damage Control principles (1:1:1 balanced transfusion of PRBCs, FFP, platelets; early Tranexamic Acid within 3 hours; permissive hypotension SBP 80-90 mmHg); however, permissive hypotension is STRICTLY CONTRAINDICATED in Traumatic Brain Injury (TBI), where avoiding hypotension (SBP <90 mmHg) and hypoxia (PaO₂ <60 mmHg) is paramount.
- Major burn resuscitation utilizes the Parkland formula (4 mL × kg × %TBSA in 24h: 50% in the first 8h from injury, 50% in the remaining 16h; target UOP 0.5-1.0 mL/kg/hr); Succinylcholine is safe in the first 24-48 hours but is STRICTLY CONTRAINDICATED after 24-48 hours for 1-2 years due to extrajunctional receptor upregulation and lethal hyperkalemic cardiac arrest.
Last updated: August 2026
20.3 ENT/Shared Airway, Extrathoracic Procedures & Trauma/Burn Resuscitation
Shared airway surgery, complex extrathoracic procedures, and emergency trauma/burn resuscitation require rapid clinical decision-making, specialized equipment mastery, and precise pharmacological knowledge. Anesthesia providers must effectively prevent and manage intraoperative airway fires, stabilize the bleeding pediatric tonsil, surveil delayed toxicity from tumescent local anesthetics, optimize cerebral perfusion during damage control trauma resuscitation, and navigate altered neuromuscular pharmacology in thermal burn injury.
1. ENT Shared Airway & Laser Surgery Fire Safety
Surgical procedures involving the larynx, vocal cords, or trachea frequently utilize surgical lasers (CO₂, Nd:YAG, KTP) within a shared airway environment. This creates a high-risk environment for operating room airway fires.
+---------------------------------------------------------------------------------------------------------+
| THE SURGICAL FIRE TRIAD |
+-----------------------+--------------------------------------+------------------------------------------+
| Triad Component | Operative Source | Anesthetic Prevention Strategies |
+-----------------------+--------------------------------------+------------------------------------------+
| **1. Oxidizer** | • Oxygen (O₂)
• Nitrous Oxide (N₂O) | • Maintain **FiO₂ ≤ 0.30 (30%)** with air|
| | (N₂O supports combustion identically| • **STRICTLY AVOID N₂O** in laser surgery|
+-----------------------+--------------------------------------+------------------------------------------+
| **2. Fuel** | • Endotracheal tube (PVC, silicone) | • Use **Laser-Safe Metal/Foil-Wrapped ETT|
| | • Drapes, sponges, surgical prep | • Wet cotton pledges/sponges in pharynx |
| | • Tracheal tissue / hair / fat | • Dry alcohol-based preps ≥ 3 minutes |
+-----------------------+--------------------------------------+------------------------------------------+
| **3. Ignition Source**| • Surgical Laser (CO₂, Nd:YAG, KTP) | • Place laser in **STANDBY mode** when not|
| | • Electrocautery (Bovie) | actively in the surgeon's hands |
+-----------------------+--------------------------------------+------------------------------------------+
Laser-Safe Endotracheal Tubes & Dual-Cuff Protocol
- Standard PVC Tubes: Highly flammable; laser strike immediately ignites PVC, producing a blowtorch effect that releases toxic hydrogen chloride gas into the bronchial tree. Standard PVC tubes are strictly prohibited during laser airway surgery.
- Specialized Laser Tubes: Constructed of flexible stainless steel (e.g., Laser-Flex) or silicone wrapped in copper/aluminum foil with an outer Teflon coating.
- Dual-Cuff Management: Laser-safe tubes feature two separate cuffs (proximal and distal). Both cuffs are inflated with sterile saline tinted with methylene blue:
- The saline acts as a physical heat sink/flame retardant.
- If the laser accidentally strikes the proximal cuff, the blue saline leaks, immediately alerting the team to cuff puncture while quenching potential sparks; the intact distal cuff continues to protect the lower airway from aspiration and maintain positive pressure ventilation.
[IMMEDIATE AIRWAY FIRE EMERGENCY PROTOCOL]
[STEP 1: SIMULTANEOUS ACTION - HALT & EXTUBATE]
• **IMMEDIATELY EXTUBATE the burning endotracheal tube**
• **HALT all ventilation & STOP gas flow**
• Remove all burning sponges/drapes from airway
|
v
[STEP 2: EXTINGUISH BURNING TISSUES]
• **Pour sterile saline or sterile water directly into airway**
|
v
[STEP 3: ISOLATE OXIDIZERS]
• Turn off oxygen and gas flows at machine/wall
|
v
[STEP 4: RESTORE VENTILATION]
• Resume mask ventilation with **100% O₂** (or air)
• Avoid flammable materials; re-intubate with standard ETT
|
v
[STEP 5: ASSESS DAMAGE & MONITOR]
• Perform **Rigid/Flexible Bronchoscopy** to inspect tracheobronchial
tree, remove soot, foreign bodies, and debris
• Administer humidified O₂, steroids, and monitor in ICU for ARDS
2. Post-Tonsillectomy Hemorrhage: The "Bleeding Tonsil"
Post-tonsillectomy hemorrhage is a life-threatening pediatric emergency occurring in up to $2 - 5%$ of patients, with a bimodal distribution: Primary hemorrhage ($<24 \text{ hours}$ postop, usually due to surgical ligature slippage) and Secondary hemorrhage (Postoperative Days $5 - 10$, due to premature sloughing of the eschar/scab).
+---------------------------------------------------------------------------------------------------------+
| THE BLEEDING TONSIL CLINICAL TRIAD |
+-----------------------+--------------------------------------+------------------------------------------+
| Component | Pathophysiologic Mechanism | Clinical Anesthetic Danger |
+-----------------------+--------------------------------------+------------------------------------------+
| **1. Hypovolemia** | • Continuous slow venous or arterial | • **Severe unappreciated hypovolemic |
| | ooze; child swallows blood quietly | shock** unmasked by induction agents |
| | • Tachycardia, orthostasis, pale/cool| • Hypotension is a late, pre-terminal sign|
+-----------------------+--------------------------------------+------------------------------------------+
| **2. Full Stomach** | • Stomach filled with swallowed clots| • **Extreme aspiration risk** on induc- |
| | and active liquid blood | tion and emergence |
+-----------------------+--------------------------------------+------------------------------------------+
| **3. Difficult Air-** | • Active pharyngeal bleeding obscures| • Inability to visualize vocal cords; |
| ** way / Vision** | glottic structures and cord anatomy| equipment clogs with thick blood clots |
+-----------------------+--------------------------------------+------------------------------------------+
Anesthetic Management Plan for Bleeding Tonsil
- Resuscitation BEFORE Induction: Never induce a bleeding tonsil patient without restoring intravascular volume. Establish two large-bore IVs, draw type and crossmatch, and infuse warm crystalloid or uncrossmatched/type-specific blood until volume deficits are corrected (normalize heart rate and capillary refill).
- Airway Setup: Prepare TWO fully functional suction setups with rigid Yankauer tips connected to distinct vacuum canisters. Have multiple video laryngoscope and direct laryngoscope blades ready, along with a styletted ETT and a smaller size (downsized by 0.5-1.0 mm).
- Induction: Perform a Rapid Sequence Induction (RSI) with cricoid pressure. Position patient in slight Trendelenburg or left tilt to allow blood to pool in the upper pharynx away from the laryngeal inlet.
- Gastric Evacuation: Following successful tracheal intubation, pass a large-bore orogastric tube (Ewald or 18 Fr OG tube) under direct visualization to aggressively decompress and evacuate swallowed blood clots from the stomach. This prevents postoperative vomiting, aspiration, and severe nausea.
- Extubation: The patient MUST be extubated fully awake, responsive, with return of intact airway protective reflexes, positioned in the lateral "tonsil position" (recovery position).
3. Tumescent Liposuction & Delayed LAST
Tumescent liposuction involves subcutaneous infiltration of large volumes of crystalloid containing dilute local anesthetic and epinephrine into adipose tissue prior to suction aspiration.
+---------------------------------------------------------------------------------------------------------+
| TUMESCENT ANESTHESIA SOLUTION FORMULATION |
+-----------------------+--------------------------------------+------------------------------------------+
| Component | Typical Concentration | Pharmacologic Function |
+-----------------------+--------------------------------------+------------------------------------------+
| **Dilute Lidocaine** | **0.05% - 0.1%** (500 - 1000 mg/L) | • Local anesthesia across surgical field |
+-----------------------+--------------------------------------+------------------------------------------+
| **Epinephrine** | **1:1,000,000** (1 mg/L) | • Intense subcutaneous vasoconstriction; |
| | | minimizes surgical blood loss (<1%) |
+-----------------------+--------------------------------------+------------------------------------------+
| **Sodium Bicarbonate**| **10 mEq / L** | • Neutralizes acidity; speeds onset and |
| | | dramatically reduces injection pain |
+-----------------------+--------------------------------------+------------------------------------------+
| **Carrier Fluid** | 0.9% Normal Saline or Lactated Ringer| • Tumescence and tissue expansion |
+-----------------------+--------------------------------------+------------------------------------------+
Maximum Dosing & Unique Pharmacokinetics
- Standard Max Lidocaine Dose: $4.5 \text{ mg/kg}$ plain, or $7.0 \text{ mg/kg}$ with epinephrine.
- Tumescent Max Lidocaine Dose: Up to $35 - 55 \text{ mg/kg}$.
- Mechanism of Safety: Intense epinephrine-mediated vasoconstriction, high lipid solubility of lidocaine in avascular adipose tissue, and mechanical removal of a portion of the injected drug during aspiration slow systemic vascular absorption.
- The 12-to-14-Hour Delayed Peak: Unlike standard peripheral nerve blocks (where peak plasma levels occur in $15 - 45 \text{ minutes}$ delays), peak plasma lidocaine concentrations following tumescent infiltration occur $12 \text{ to } 14 \text{ hours}$ post-infiltration (range: $8 - 16 \text{ hours}$).
- Clinical Warning: Patients discharged home on the afternoon of surgery may develop life-threatening Local Anesthetic Systemic Toxicity (LAST) late at night or the following morning. Educate patients and families on symptoms of LAST (perioral numbness, tinnitus, metallic taste, visual changes, muscle twitches, seizures, cardiovascular collapse). If LAST occurs, immediately administer 20% Lipid Emulsion (1.5 mL/kg bolus over 1 min, then 0.25 mL/kg/min infusion).
4. Trauma Resuscitation: Damage Control vs. Traumatic Brain Injury
+---------------------------------------------------------------------------------------------------------+
| THE TRAUMA LETHAL DIAMOND |
+---------------------------------------------------------------------------------------------------------+
| 1. **Hypothermia** (<35°C) → Impairs coagulation enzyme kinetics & platelet function |
| 2. **Coagulopathy** (Trauma-ind)→ Consumption of clotting factors & accelerated fibrinolysis |
| 3. **Acidosis** (pH < 7.20) → Drastically reduces thrombin generation & myocardial contractility |
| 4. **Hypocalcemia** (iCa < 1.1) → Citrate toxicity from PRBCs; impairs clotting cascade & vascular tone|
+---------------------------------------------------------------------------------------------------------+
Damage Control Resuscitation (DCR) in Non-Head Injured Trauma
- Balanced Hemostatic Transfusion: Early administration of packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets in a $1:1:1$ ratio to prevent dilution of clotting factors and thrombocytopenia.
- Early Tranexamic Acid (TXA): Administer $1 \text{ g IV}$ over 10 minutes within 3 hours of injury (CRASH-2 trial), followed by $1 \text{ g}$ infused over 8 hours to halt hyperfibrinolysis.
- Permissive Hypotension: Maintain a systolic blood pressure of $80 - 90 \text{ mmHg}$ (MAP $50 - 60 \text{ mmHg}$) until surgical or angiographic hemostasis is achieved. This prevents "popping the clot" and dislodging fragile early platelet plugs.
The Inviolable Exception: Traumatic Brain Injury (TBI)
NCE Clinical Rule — TBI Hemodynamic Targets: Permissive hypotension is STRICTLY CONTRAINDICATED in the presence of Traumatic Brain Injury (TBI) or spinal cord trauma. A single episode of systolic hypotension ($SBP < 90 \text{ mmHg}$) or arterial hypoxemia ($PaO_2 < 60 \text{ mmHg}$ or $SpO_2 < 90%$) doubles mortality in head-injured patients.
+---------------------------------------------------------------------------------------------------------+
| RESUSCITATION TARGET COMPARISON MATRIX |
+-----------------------+--------------------------------------+------------------------------------------+
| Resuscitation Target | Non-TBI Hemorrhagic Trauma (DCR) | Polytrauma with Traumatic Brain Injury |
+-----------------------+--------------------------------------+------------------------------------------+
| **Systolic BP (SBP)** | **80 - 90 mmHg** (Permissive Hypo) | **≥ 100 - 110 mmHg** (AVOID SBP <90!) |
+-----------------------+--------------------------------------+------------------------------------------+
| **Mean Arterial Press**| **50 - 60 mmHg** | **≥ 80 mmHg** |
+-----------------------+--------------------------------------+------------------------------------------+
| **CPP Target** | N/A | **60 - 70 mmHg** |
+-----------------------+--------------------------------------+------------------------------------------+
| **Ventilation Target**| Normocarbia | **Normocarbia (PaCO₂ 35 - 40 mmHg)** |
| | | Prophylactic hyperventilation is HARMFUL |
+-----------------------+--------------------------------------+------------------------------------------+
| **Airway Precautions**| Standard RSI | **Manual In-Line Stabilization (MILS)** |
| | | Avoid neck extension (protect C-spine) |
+-----------------------+--------------------------------------+------------------------------------------+
5. Major Burn Resuscitation: The Parkland Formula
Thermal burn injuries covering $\ge 20%$ of Total Body Surface Area (TBSA) precipitate massive systemic capillary leak, hypovolemic-distributive burn shock, and profound metabolic alterations.
[THE RULE OF NINES FOR ADULT BURN TBSA]
[Head & Neck] = 9%
[Anterior Torso] = 18% [Posterior Torso] = 18%
[Each Arm (x2)] = 9% each (18% total)
[Each Leg (x2)] = 18% each (36% total)
[Perineum / Genitalia] = 1%
-----------------------------------------
Total Body Surface Area = 100%
The Parkland (Baxter) Fluid Formula
+-------------------------------------------------------------------------+
| PARKLAND RESUSCITATION TIME TIMELINE |
+-------------------------------------------------------------------------+
| • FIRST 8 HOURS (FROM TIME OF INJURY): |
| Administer **50% of the total calculated 24-hour volume** |
| *Caution:* Clock starts at the **MOMENT OF BURN**, NOT hospital arrival|
| |
| • REMAINING 16 HOURS: |
| Administer the remaining **50% of the calculated volume** |
+-------------------------------------------------------------------------+
Calculation Example: An 80 kg adult with a 40% TBSA burn:
-
$\text{Total 24-hr Fluid} = 4 \text{ mL} \times 80 \text{ kg} \times 40 = 12,800 \text{ mL} \text{ (12.8 L of LR)}$
-
First 8 hours: $12,800 \times 0.5 = 6,400 \text{ mL}$ ($800 \text{ mL/hr}$)
-
Next 16 hours: $12,800 \times 0.5 = 6,400 \text{ mL}$ ($400 \text{ mL/hr}$)
-
Resuscitation Endpoint: Titrate fluid rates to maintain adult Urine Output at $0.5 - 1.0 \text{ mL/kg/hr}$ ($1.0 - 2.0 \text{ mL/kg/hr}$ in children under 30 kg). Avoid "fluid creep" and over-resuscitation, which cause abdominal compartment syndrome and pulmonary edema.
6. Specialized Burn Pharmacology: Neuromuscular Junction Dynamics
Thermal injury alters the structure and density of nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction, fundamentally altering neuromuscular blocker pharmacology.
+---------------------------------------------------------------------------------------------------------+
| BURN NEUROMUSCULAR PHARMACOLOGY MATRIX |
+-----------------------+--------------------------------------+------------------------------------------+
| Neuromuscular Agent | Post-Burn Time Window | Clinical Effect & Molecular Mechanism |
+-----------------------+--------------------------------------+------------------------------------------+
| **Succinylcholine** | **First 24 to 48 Hours Post-Burn** | • **SAFE to administer** |
| (Depolarizing) | | • Normal baseline potassium release (~0.5|
| | | mEq/L); receptors not yet upregulated |
+-----------------------+--------------------------------------+------------------------------------------+
| **Succinylcholine** | **> 24 - 48 Hours up to 1 - 2 Years**| • **STRICTLY CONTRAINDICATED (LETHAL!)** |
| (Depolarizing) | (or until fully healed/rehabilitated)| • Extrajunctional receptor upregulation |
| | | causes massive $K^+$ surge ($>8-10$) |
| | | → **Refractory VFib & Asystolic Arrest**|
+-----------------------+--------------------------------------+------------------------------------------+
| **Non-Depolarizing** | **> 24 - 48 Hours Post-Burn** | • **MARKED RESISTANCE (Decreased Sens.)**|
| **NMBs (Rocuronium,** | | • Dose requirement is **2 to 3-fold** |
| **Vecuronium, Cis)** | | **higher**; shorter duration of action |
| | | • More receptors require more antagonist |
+-----------------------+--------------------------------------+------------------------------------------+
| **Pseudocholinester-**| Post-Burn Hospital Course | • **Decreased activity** (hepatic impair)|
| ** ase Enzyme** | | • Prolongs mivacurium & ester locals |
+-----------------------+--------------------------------------+------------------------------------------+
Molecular Mechanism of Extrajunctional Receptor Proliferation
Starting 24 hours after a major thermal injury, the neuromuscular junction undergoes massive structural remodeling:
- Receptor Proliferation: Fetal embryonic isoform ($\alpha_1\beta_1\gamma\delta$) and neuronal ($\alpha_7$) nicotinic acetylcholine receptors proliferate and spread across the entire skeletal muscle sarcolemma beyond the motor endplate.
- Channel Kinetics: These immature extrajunctional receptors remain open longer when depolarized by succinylcholine, permitting massive, uncontrolled intracellular potassium ($K^+$) efflux into systemic circulation.
- Non-Depolarizer Competition: Because the total population of acetylcholine receptors across the muscle membrane is dramatically increased, significantly higher concentrations of competitive antagonists (Rocuronium, Vecuronium, Cisatracurium) are required to occupy $\ge 75 - 90%$ of receptors to achieve surgical muscle relaxation.
Loading diagram...
Test Your Knowledge
During a laryngeal mass resection with a CO₂ laser under general endotracheal anesthesia (FiO₂ 0.30 in air), a sudden flash and black smoke erupt from the patient's mouth. Which sequence of actions must the anesthesia team execute immediately?
A
B
C
D
Test Your Knowledge
A 38-year-old female undergoes extensive tumescent liposuction under general anesthesia. A total of 4 liters of tumescent solution containing 0.05% lidocaine with 1:1,000,000 epinephrine (total lidocaine dose 35 mg/kg) is infiltrated into abdominal and thigh adipose tissue. When are peak systemic plasma lidocaine concentrations expected to occur, and what is the primary risk during that timeframe?
A
B
C
D
Test Your Knowledge
A 70 kg male sustained 2nd and 3rd degree flame burns covering 50% of his total body surface area in a house fire that occurred 2 hours ago. Using the Parkland (Baxter) formula, what is his total calculated crystalloid requirement for the first 24 hours, and at what infusion rate should Lactated Ringer's be administered over the next 6 hours?
A
B
C
D
Test Your Knowledge
A 32-year-old male who sustained a 35% total body surface area burn 5 days ago requires surgical debridement and skin grafting in the operating room. Which statement regarding his neuromuscular blocker pharmacology is entirely accurate?
A
B
C
D