7.3 Respiration, Circulation, Shock, Burns, and Environmental Injuries

Respiration, Circulation, Shock, Burns, and Environmental Injuries

Core Doctrine: Under TC 4-02.1 (First Aid) and ATP 4-02.83 (Tactical Combat Casualty Care), the secondary phases of the MARCH PAWS protocol address thoracic trauma, circulatory collapse, hypothermia, and specialized battlefield injuries. Noncommissioned officers must possess mastery of thoracic decompression landmarks, the trauma lethal triad, ocular protection, and environmental heat and cold casualty management.

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1. R — Respiration: Thoracic Trauma and Vented Chest Seals

Thoracic injuries account for more than a third of all preventable battlefield deaths. Penetrating trauma from fragmentation, shrapnel, or gunshot wounds compromises the closed negative-pressure mechanics of the thoracic cavity.

Open / Sucking Chest Wound (Communicating Pneumothorax)

When a projectile creates a hole in the chest wall that is approximately two-thirds the diameter of the trachea or larger, air preferentially enters the pleural space through the chest wall defect during inspiration rather than through the trachea. This collapses the ipsilateral lung and impairs gas exchange.

   COMMUNICATING PNEUMOTHORAX MANAGEMENT STANDARD
   ─────────────────────────────────────────────────────────────────
   1. Wipe away blood, perspiration, and dirt from the wound margins.
   2. Apply a CoTCCC-recommended VENTED CHEST SEAL during exhalation.
   3. Center the one-way valve directly over the puncture defect.
   4. Inspect for additional wounds: 'Treat the front, treat the back.'
      Check axillae, flanks, neck, and gluteal folds.
   5. Apply a second vented chest seal to all exit wounds.
   ─────────────────────────────────────────────────────────────────

Why Vented Seals are Mandatory: Non-vented occlusive dressings (such as plastic wrappers or Vaseline gauze taped on four sides) trap air as blood or tissue clots occlude the margins. CoTCCC guidelines mandate vented chest seals (such as the Halo, Chest Seal Vented, or Fox Chest Seal), which feature one-way valves that allow trapped air and blood to escape during exhalation while preventing ambient air entry during inspiration.

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2. Tension Pneumothorax: Recognition and Needle Chest Decompression (NCD)

Tension pneumothorax is the second leading cause of preventable combat death (33% of preventable fatalities). It occurs when a one-way valve mechanism allows air to enter the pleural space during inhalation but prevents its escape during exhalation. Intratoracic pressure rises progressively, completely collapsing the affected lung and shifting the mediastinal structures toward the opposite hemithorax.

Pathophysiological Cascade of Tension Pneumothorax:

1. Complete collapse of the ipsilateral lung creates profound ventilation-perfusion mismatch and hypoxia.
2. Mediastinal shift kinks the superior and inferior vena cava, obstructing venous blood return to the right atrium.
3. Preload drops to near zero, precipitating catastrophic obstructive shock, profound hypotension, and pulseless electrical activity (PEA) arrest.

   SIGNS AND SYMPTOMS OF TENSION PNEUMOTHORAX
   ─────────────────────────────────────────────────────────────────
   Early / Progressive Signs:      Late / Terminal Signs:
   • Progressive severe dyspnea    • Tracheal deviation away from
   • Tachypnea & air hunger          affected side (rare/very late)
   • Unilateral absent or markedly • Profound hypotension / shock
     decreased breath sounds       • Cyanosis (blue lips/fingers)
   • Hyperresonance on percussion  • Jugular venous distension (JVD)
   • Rapidly falling SpO2 (<90%)   • Loss of consciousness / arrest
   ─────────────────────────────────────────────────────────────────

Immediate Tactical Interventions

1. Burp the Chest Seal: If a vented chest seal is already in place, lift one edge of the seal ("burp" the seal) to break any mechanical occlusion or clot, allowing trapped pressurized air to escape with an audible hiss.
2. Needle Chest Decompression (NCD): If burping the seal fails to relieve distress, or if no chest seal is present, immediately execute an emergency NCD.

NCD Equipment and Anatomical Landmarks

• Catheter Specifications: CoTCCC doctrine requires a 10-gauge or 14-gauge, 3.25-inch needle catheter. Standard 1.5-inch IV needles are strictly prohibited because they fail to penetrate the muscular chest wall and reach the pleural cavity in over 50% of combat soldiers.

   APPROVED ANATOMICAL INSERTION LANDMARKS FOR NCD
   ─────────────────────────────────────────────────────────────────
   Site 1: 2nd Intercostal Space, Midclavicular Line (2nd ICS MCL)
   • Locate the clavicle (collarbone) on the injured side.
   • Move down two finger-breadths to find the 2nd intercostal space.
   • Center the landmark along the midclavicular line (in line with pupil).
   • Insert needle directly OVER THE TOP of the 3rd rib to avoid the
     intercostal neurovascular bundle running along the rib's lower edge.
   
   Site 2: 5th Intercostal Space, Anterior Axillary Line (5th ICS AAL)
   • Located laterally on the chest wall in the 5th intercostal space
     (approximately level with the male nipple), anterior to the
     midaxillary line.
   • Preferred by many providers due to thinner chest wall anatomy.
   ─────────────────────────────────────────────────────────────────

Step-by-Step NCD Procedure:

1. Cleanse site rapidly with alcohol or betadine if time permits.
2. Insert the 3.25-inch needle catheter at a 90-degree angle (perpendicular) to the chest wall directly over the top of the lower rib.
3. Advance firmly until the needle penetrates the parietal pleura (often felt as a distinct "pop" accompanied by a hiss of escaping air).
4. Advance the plastic catheter fully over the needle into the pleural space.
5. Withdraw the needle while holding the catheter in place; discard needle in sharps container.
6. Secure the catheter hub to the chest wall; monitor for clinical improvement (improved respiratory effort, rising oxygen saturation, return of radial pulse).

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3. C — Circulation: Pelvic Stabilization and Hemorrhagic Shock

In the Circulation phase, responders reassess all previously placed tourniquets and dressings, palpate pulses, and stabilize occult internal bleeding sources.

Pulse Assessment and Blood Pressure Estimates

• Radial Pulse Present: Systolic blood pressure (SBP) is generally at least 80 mmHg, indicating adequate cerebral and vital organ perfusion.
• Radial Pulse Absent, Carotid Pulse Present: SBP is approximately 60 to 70 mmHg, indicating severe uncompensated hemorrhagic shock requiring immediate fluid resuscitation by a combat medic.
• Capillary Refill: Normal capillary refill is less than 2 seconds. Sluggish refill (>3 seconds) indicates peripheral vasoconstriction and hypoperfusion.

Pelvic Fracture Management: The SAM Pelvic Sling

High-energy blast trauma from improvised explosive devices (IEDs) or vehicle rollovers frequently fractures the pelvic ring. A disrupted pelvic ring creates a massive internal void capable of sequestering the casualty's entire circulating blood volume into the retroperitoneum without external bleeding signs.

• Device: SAM Pelvic Sling II.
• Anatomical Placement Standard: Center the sling directly over the greater trochanters of the femurs (the bony lateral prominences of the upper hips/thighs). Never place the sling over the iliac crests (waist), which fails to close the pelvic volume.
• Application: Slide sling under knees and slide up to hips; thread buckle strap through buckle; pull strap until the patented buckle audibly clicks (signaling 33 lbs of compressive force achieved); secure strap to Velcro.

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4. H — Hypothermia Prevention and the Trauma "Lethal Triad"

Hypothermia in combat trauma is not simply being cold—it is a lethal physiological failure state. The Trauma Lethal Triad represents a self-reinforcing vicious cycle:

                    ┌────────────────────────┐
                    │      HYPOTHERMIA       │
                    │ (Core Temp < 95°F/35°C)│
                    └───────────┬────────────┘
                                │
                ┌───────────────┴───────────────┐
                ▼                               ▼
     ┌──────────────────────┐        ┌──────────────────────┐
     │     COAGULOPATHY     │◄──────►│       ACIDOSIS       │
     │ Clotting factors fail│        │ Lactic acid buildup  │
     │ Massive hemorrhage   │        │ Anaerobic metabolism │
     └──────────────────────┘        └──────────────────────┘

1. Hypothermia: Severe blood loss reduces oxygen delivery and disrupts thermoregulation. Clotting enzyme cascades become biochemically paralyzed when core body temperature drops below 35°C (95°F).
2. Acidosis: Hypoperfusion forces tissues into anaerobic metabolism, producing massive lactic acid accumulations that depress myocardial contractility.
3. Coagulopathy: Acidic, cold blood cannot form stable fibrin clots, causing uncontrolled continuous bleeding from otherwise minor or stabilized wounds.

The Desert Hypothermia Paradox: Noncommissioned officers must understand that hypothermia occurs frequently in hot desert environments (e.g., 100°F+ ambient heat in Iraq or the Mojave Desert). Hemorrhagic shock, peripheral vasoconstriction, removal of body armor, and laying on the ground rapidly induce fatal hypothermia.

Active and Passive Hypothermia Protocol:

• Passive Warming: Remove wet uniforms; insulate casualty from the cold ground by placing a closed-cell foam pad, poncho, or litter between the casualty and the earth.
• Active Warming: Apply a Ready-Heat blanket (chemically activated heating blanket) to the casualty's torso. Never place a Ready-Heat blanket directly against bare skin, as it can reach temperatures exceeding 104°F and cause full-thickness thermal burns; always place over an undergarment or shirt.
• Enclosure: Enclose the casualty completely within the Hypothermia Prevention and Management Kit (HPMK) or Blizzard Survival Blanket.

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5. PAWS: Secondary Assessment Protocol

Once MARCH interventions are secured, providers transition to the PAWS sequence:

P — Pain Management

Non-medic first responders administer the Combat Wound Medication Pack (CWMP) carried in every soldier's IFAK for mild-to-moderate pain:

• Meloxicam (Mobic): 15 mg oral tablet (an NSAID that uniquely does not inhibit platelet aggregation or increase bleeding).
• Acetaminophen (Tylenol): Two 500 mg tablets (1,000 mg total) for pain control.
• Note: Medics administer oral transmucosal fentanyl citrate (OTFC) 800 mcg lozenge or IV/IM ketamine for severe trauma.

A — Antibiotics

Every casualty with an open combat wound receives prophylactic antibiotics from the CWMP to prevent wound sepsis and osteomyelitis:

• Moxifloxacin (Avelox): 400 mg oral tablet once daily. Broad-spectrum fluoroquinolone effective against Gram-positive and Gram-negative combat flora.

W — Wounds (Specialized Battlefield Trauma)

• Penetrating Eye Trauma: If an eye is punctured or lacerated, immediately place a rigid eye shield (Fox eye shield) over the eye, securing it with tape. The shield must rest on the bony orbital ridges of the brow and cheek.
  • MANDATORY RULE: NEVER apply a pressure bandage or patch over an injured eye. External compression crushes the globe and forces intraocular contents (vitreous humor) out through the laceration, causing permanent blindness.
• Burns: Stop the burning process; remove rings, watches, and restrictive gear; estimate burn surface area using the Rule of Nines; cover burns with clean, dry, sterile dressings or burn sheets. Never apply greasy ointments, ice, or wet soaks (wet soaks accelerate hypothermia).

   RULE OF NINES (ADULT BURN ESTIMATION)
   ─────────────────────────────────────────────────────────────────
   Anatomical Region                      Total Body Surface Area
   ─────────────────────────────────────────────────────────────────
   Head and Neck (Front & Back)                      9%
   Anterior Torso (Chest & Abdomen)                 18%
   Posterior Torso (Upper & Lower Back)             18%
   Each Upper Extremity (Arm, Forearm, Hand)         9% each (18% total)
   Each Lower Extremity (Thigh, Leg, Foot)          18% each (36% total)
   Perineum / Genitalia                              1%
   ─────────────────────────────────────────────────────────────────
   Total:                                          100%

S — Splinting

Immobilize all suspected fractures using SAM splints or rigid materials. Always assess and document Pulse, Motor, and Sensory (PMS) distal to the injury both before and after applying the splint.

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6. Environmental Injuries: Heat and Cold Casualties

Promotion board candidates are routinely tested on distinguishing life-threatening environmental casualties.

Heat Illness Spectrum

Board Distinction: The absolute differentiator between heat exhaustion and heat stroke is mental status. Any heat casualty demonstrating confusion, irrational behavior, delirium, or loss of consciousness is classified as Heat Stroke and requires immediate, aggressive whole-body cooling.

Cold Injuries

• Trench Foot (Immersion Foot): Caused by prolonged exposure of feet to wet, non-freezing conditions (32°F to 50°F). Characterized by numbness, pale/cyanotic skin, and tissue maceration. Prevented by keeping feet clean and changing dry socks daily.
• Frostbite: Actual freezing of cellular fluid within tissues. Superficial (skin is white/waxy, pliable underneath) vs. Deep (skin is hard, wooden, non-pliable, blisters form).
  • CRITICAL RULE: Never rub frozen tissue or apply snow. Rubbing drives sharp ice crystals through cell membranes, destroying tissue. Do not attempt to thaw tissue in the field if there is any risk of refreezing before reaching definitive care.