10.4 Submersion Injuries, Drowning & Thermal/Burn Emergencies

10.4 Submersion Injuries, Drowning & Thermal/Burn Emergencies

Submersion injuries, severe hypothermia, and thermal burn trauma represent multi-system pediatric emergencies requiring precise, protocolized nursing care. Pediatric anatomy—specifically a large surface-area-to-body-mass ratio, thinner skin, smaller glycogen stores, and non-compliant pediatric airways—amplifies the physiological impact of environmental trauma.

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Pathophysiology of Drowning & Submersion Injuries

Drowning is defined as the process resulting in primary respiratory impairment from submersion or immersion in liquid. (Outdated terms such as 'near-drowning', 'wet drowning', or 'dry drowning' must no longer be used).

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|                           PATHOPHYSIOLOGY OF DROWNING                                   |
+-----------------------------------------------------------------------------------------+
|  SUBMERSION IN LIQUID -> Involuntary breath-holding & liquid swallowing                 |
|       |                                                                                 |
|       v                                                                                 |
|  REFLEX LARYNGOSPASM -> Inability to ventilate -> Hypoxia & Hypercapnia                 |
|       |                                                                                 |
|       v                                                                                 |
|  LIQUID ASPIRATION -> Washout & deactivation of pulmonary surfactant                     |
|       |                                                                                 |
|       v                                                                                 |
|  ALVEOLAR COLLAPSE & ATELECTASIS -> Non-cardiogenic Pulmonary Edema (ARDS)              |
|       |                                                                                 |
|       v                                                                                 |
|  PROFOUND HYPOXEMIA & ISCHEMIA -> Hypoxic-Ischemic Encephalopathy (HIE) & Cardiac Arrest|
+-----------------------------------------------------------------------------------------+

Clinical Management Priorities

• Hypoxia is the Primary Instigator: Resuscitation begins with immediate ventilation (5 initial rescue breaths) followed by conventional CPR (30:2 single rescuer, 15:2 two-rescuer).
• Pulmonary Complications: Aspiration of fresh or salt water damages alveolar-capillary membranes and washes out surfactant, leading to intrapulmonary shunting, non-cardiogenic pulmonary edema, and Acute Respiratory Distress Syndrome (ARDS).
• Cervical Spine Immobilization: Indicated ONLY if there is a history of diving, high-speed watercraft trauma, falling from height, or signs of blunted trauma.
• Observation Threshold: Any pediatric submersion patient who experienced loss of consciousness, required resuscitation, or displays tachypnea, cough, or crackles must be monitored for at least 6 to 8 hours, as ARDS can develop insidiously.

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Hypothermia Resuscitation Protocols

Hypothermia occurs rapidly in submerged or burned children due to high body surface area. Core body temperature classification:

• Mild Hypothermia: $32^\circ C - 35^\circ C$ ($89.6^\circ F - 95^\circ F$). Passive external rewarming.
• Moderate Hypothermia: $28^\circ C - 32^\circ C$ ($82.4^\circ F - 89.6^\circ F$). Active external rewarming.
• Severe Hypothermia: $< 28^\circ C$ ($< 82.4^\circ F$). Active internal (core) rewarming.

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|                        HYPOTHERMIA RESUSCITATION MODIFICATIONS                          |
+-----------------------------------------------------------------------------------------+
| CORE TEMP < 30°C (86°F)  | - Limit defibrillation shocks to 1 - 3 attempts              |
|                          | - WITHHOLD ALL IV ACLS MEDICATIONS (Epineph/Amio)            |
|                          | - Initiate aggressive active core rewarming                  |
+--------------------------+--------------------------------------------------------------+
| CORE TEMP 30°C - 35°C    | - Double the time interval between IV ACLS medication doses  |
|                          | - Continue active external and internal rewarming            |
+--------------------------+--------------------------------------------------------------+
| CPR TERMINATION RULE     | - "PATIENT IS NOT DEAD UNTIL WARM AND DEAD"                  |
|                          | - Continue CPR until core temp > 32°C - 35°C before stopping |
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Rewarming Methods

• Passive External: Remove wet clothing, warm dry blankets, warm ambient room ($30^\circ C$).
• Active External: Radiant warmers, forced-air warming blankets (Bair Hugger), warm water immersion.
• Active Internal (Core): Humidified warm oxygen ($42^\circ C - 46^\circ C$), warm IV fluids ($39^\circ C - 42^\circ C$), warm pleural or peritoneal lavage, extracorporeal membrane oxygenation (ECMO) / cardiopulmonary bypass.

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Pediatric Burn Assessment: Lund-Browder vs. Rule of Nines

Accurate calculation of Total Body Surface Area (TBSA) burned is essential for fluid resuscitation. Superficial (1st-degree) burns (sunburns) ARE EXCLUDED from TBSA fluid calculations. Only partial-thickness (2nd-degree) and full-thickness (3rd/4th-degree) burns are included.

Why the Adult Rule of Nines Fails in Children

Infants and young children have a significantly larger head surface area and smaller lower extremity surface area relative to adults. Using the adult Rule of Nines severely underestimates head burn TBSA and overestimates leg burn TBSA in pediatric patients.

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|                BURN TBSA ESTIMATION: LUND-BROWDER vs. RULE OF NINES                     |
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| BODY REGION            | INFANT (< 1 YEAR)     | 5-YEAR-OLD CHILD   | ADULT             |
+------------------------+-----------------------+--------------------+-------------------+
| Head & Neck            | **18%**               | **13%**            | 9%                |
| Anterior Trunk         | 18%                   | 18%                | 18%               |
| Posterior Trunk        | 18%                   | 18%                | 18%               |
| Each Upper Extremity   | 9%                    | 9%                 | 9%                |
| Each Lower Extremity   | **14%**               | **16.5%**          | 18%               |
| Perineum               | 1%                    | 1%                 | 1%                |
+-----------------------------------------------------------------------------------------+

Palmar Method for Patchy Burns: The area of the patient's hand (palm plus digits) equals approximately 1% TBSA. Use this method to quickly estimate scattered burn patches.

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Pediatric Burn Fluid Resuscitation Formulas

Massive capillary leak occurs following burn trauma, peaking at 8 to 24 hours post-injury.

1. Modified Parkland Resuscitation Formula

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

• Fluid of Choice: Lactated Ringer's (LR).
• Time Administration Schedule:
  • First 50% of total calculated volume is administered over the first 8 hours post-injury (calculated from the time the burn occurred, NOT ED arrival time).
  • Remaining 50% of volume is administered over the next 16 hours.

2. CRITICAL MANDATE: Concurrent Dextrose Maintenance

Young children ($< 30 \text{ kg}$) have limited hepatic glycogen reserves. If resuscitated solely with dextrose-free Parkland fluid, they will develop life-threatening hypoglycemia.

THE CPEN BURN RULE: For children $< 30 \text{ kg}$, emergency nurses MUST administer maintenance fluids containing Dextrose (e.g., $D_5 0.45\% \text{ Normal Saline}$) CONCURRENTLY with Parkland LR fluid resuscitation!

$$\text{4-2-1 Rule for Hourly Maintenance} = (4 \text{ mL/kg for first 10 kg}) + (2 \text{ mL/kg for next 10 kg}) + (1 \text{ mL/kg for remaining kg})$$

Resuscitation Target: Urine Output Titration

Do not titrate burn fluids based on blood pressure alone! Titrate fluid rates to maintain goal urine output:

• Infants & Children (< 30 kg): $1.0 - 2.0 \text{ mL/kg/hr}$.
• Older Children & Adolescents (> 30 kg): $0.5 - 1.0 \text{ mL/kg/hr}$.

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Inhalation Injury & Thermal Airway Emergencies

Inhalation injury dramatically increases mortality in burn trauma.

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|                         INHALATION INJURY CLINICAL TRIAD                                |
+-----------------------------------------------------------------------------------------+
|  PHYSICAL SIGNS     | Facial burns, singed nasal hairs, soot in mouth, dark sputum      |
|  AIRWAY SYMPTOMS    | Hoarseness, brassy cough, inspiratory stridor, intercostal retractions|
|  SYSTEMIC TOXICITY  | Carbon Monoxide (CO) poisoning & Cyanide toxicity                 |
+-----------------------------------------------------------------------------------------+

1. Thermal Airway Edema

Direct heat causes rapid supraglottic edema. Immediate elective endotracheal intubation is mandatory at the earliest sign of airway involvement (hoarseness, stridor, soot in pharynx) before thermal edema completely occludes the glottic opening.

2. Carbon Monoxide (CO) Poisoning

CO binds to hemoglobin with an affinity 200 times greater than oxygen, forming carboxyhemoglobin (COHb) and shifting the oxyhemoglobin dissociation curve to the left.

• Pulse Oximetry Trap: Standard pulse oximeters ($SpO_2$) cannot distinguish carboxyhemoglobin from oxyhemoglobin and will falsely report 100% saturation!
• Diagnosis: Co-oximetry arterial or venous blood gas measuring $COHb$ percentage.
• Treatment: Administer $100\%$ high-flow oxygen via non-rebreather mask (reduces COHb half-life from 320 minutes to 80 minutes) or hyperbaric oxygen for $COHb > 25\%$ or neurological compromise.

3. Cyanide Toxicity

Produced by combustion of synthetic polymers and plastics. Suspect in patients with severe lactic acidosis ($> 8 - 10 \text{ mmol/L}$) out of proportion to burn size.

• Antidote: Intravenous Hydroxocobalamin (Cyanokit) $70 \text{ mg/kg}$ IV (max $5 \text{ g}$), which binds cyanide to form non-toxic vitamin $B_{12a}$ (cyanocobalamin) excreted in urine.