Disaster and conflict surgery, triage, blast and gunshot injuries

Overview

A disaster is any event, natural (earthquake, flood) or man-made (bomb blast, building collapse, mass shooting, industrial accident), whose casualty load overwhelms local resources. Pakistan has seen all of these: the 2005 earthquake, repeated floods and urban bomb blasts.

Conflict (war) surgery shares many features: many casualties at once, austere conditions, high-energy wounds, heavy contamination and staged care.

The aim shifts from doing everything for each patient to saving as many lives as possible with what is available ("do the most for the most").

Multiple versus mass casualties

Organising the response

Sequence of relief (Bailey & Love): establish a chain of command, set up communication, assess damage, mobilise resources, start rescue, triage, begin emergency treatment, arrange evacuation, then definitive care.

• Incident command system: one commander, clear roles (medical, triage, transport, security, communication, morgue).
• Scene safety first: rescuers must not become casualties; secondary devices are a risk after bombings.
• Hospital disaster plan: activate staff call-in, clear the emergency department, cancel elective lists, designate triage, treatment and holding areas, open a family information point, appeal for blood donors. ATLS suggests a hospital should be able to cope with a surge of about 20% above its usual load.
• Media: handled by a designated spokesperson; can help with information and appeals.
• Pakistan: district emergency services (for example Rescue 1122 in several provinces) and national and provincial disaster management authorities coordinate field response. Plans and structures change, so check current local guidance.

Timeline of disaster injuries (Bailey & Love)

Patients with head, chest and abdominal injuries are treated or have died within the first 48–72 hours. After the first week, field teams mostly see limb injuries and infected wounds. Only about 10–15% of disaster casualties need admission.

Triage

Triage (French trier, to sort) is the cornerstone of mass casualty care. It is done by a senior, experienced clinician and repeated at every step (scene, before evacuation, at hospital), because patients change.

Triage categories

Rapid field triage tools

• START-type sieve: anyone who can walk is green. For the rest, check Respiration, Perfusion and Mental status: no breathing after opening the airway = dead; respiratory rate over 30, capillary refill over 2 seconds or unable to obey simple commands = immediate; otherwise delayed.
• SALT (ATLS): Sort (by response to a spoken command, breathing and obvious bleeding), Assess, Lifesaving interventions (stop bleeding, open the airway, decompress a chest), Treatment/transport.

Triage errors

• Over-triage: minor casualties labelled immediate; swamps the hospital.
• Under-triage: critical casualties labelled delayed; causes avoidable deaths.

Decontamination (chemical, biological, radiological incidents)

• Hot zone: contaminated area. Warm zone: where decontamination happens (upwind and uphill). Cold zone: clean area for treatment.
• Removing clothing and jewellery removes most contamination. Staff must wear proper protective equipment. Decontaminate before patients enter the hospital.

Principles of disaster and war surgery

Staged care and damage control

• Field hospitals do life- and limb-saving surgery only: secure the airway (may need tracheostomy), stop bleeding, decompress (chest drain, burr hole, laparotomy, fasciotomy), remove dead and contaminated tissue, splint fractures, then evacuate.
• Military care is organised in roles: role 1 first aid and resuscitation at unit level, role 2 resuscitation with damage control surgery, role 3 deployed specialist hospital, role 4 definitive care at home base.
• <C>ABC: in war, catastrophic haemorrhage comes before airway. Tourniquets save lives in limb bleeding.
• Tactical Combat Casualty Care has three phases: care under fire (only tourniquet or haemostatic dressing while returning fire), tactical field care and tactical evacuation.

Wound management: the most tested principle

1. Give antibiotics and tetanus prophylaxis.
2. Wound excision (debridement) under tourniquet: extend the wound along the limb's long axis; remove all foreign material; irrigate generously with saline.
3. Skin: trim only the edges. Muscle: excise generously; dead muscle is the culture medium for clostridia.
4. Decompress fascial compartments (fasciotomy) in high-energy limb wounds.
5. Stabilise fractures, preferably with an external fixator.
6. Do not close the wound primarily. Dress it open with fluffed gauze, elevate the limb.
7. Re-inspect at 24–48 hours; repeat debridement if needed.
8. Delayed primary closure when clean, Bailey & Love says between the 4th and 6th day; larger defects need grafts or flaps.

Ballistics and gunshot wounds

• Kinetic energy (KE) = ½ × mass × velocity². Doubling velocity quadruples energy, so velocity matters more than bullet size.
• What harms tissue is the energy transferred to it, which rises with yaw, tumbling, deformation (expanding bullets) and fragmentation, and with dense tissue.
• Permanent cavity: the track crushed by the bullet itself.
• Temporary cavity: a short-lived cavity formed as tissue is flung outwards from the track, then collapses; it stretches and tears tissue well away from the track and sucks in contamination. ATLS notes wounding rises sharply above about 600 m/s (2000 ft/s).
• Low-energy (most handguns): damage mainly along the track. High-energy (military rifles): extensive hidden damage, comminuted fractures, devitalised muscle.
• Shotguns: lower velocity but high total mass; devastating at close range.
• Elastic tissue (lung, muscle) tolerates cavitation better than solid organs (liver), brain and bone.

Practical points:

• Mark every wound with a radio-opaque marker before X-ray to trace the track and count missiles; one hole with no exit means a retained projectile.
• Gunshot wounds crossing the peritoneum need laparotomy; small bowel is the organ hit most often.
• Retained bullets are removed if easily reached, in a joint, near vital structures, or causing symptoms; otherwise many can be left.

Blast injuries

An explosion produces a pressure wave (overpressure), followed by a blast wind, fragments and heat.

Primary blast injury in detail

• An intact eardrum does not exclude other primary blast injury (Bailey & Love), and a ruptured one is no longer used as a reliable marker of serious blast injury.
• Blast lung: alveolar haemorrhage and oedema; progressive hypoxia, haemoptysis, "bat-wing" shadows on X-ray, pneumothorax, air embolism (a cause of sudden death). Treatment is supportive; take care with positive pressure ventilation and have a low threshold for chest drains.
• Blast bowel: gas-containing gut (especially the caecum and colon) is vulnerable; perforation may appear hours to days later.
• Enclosed spaces (buses, buildings) magnify the pressure wave: more blast lung and eardrum rupture.
• The pressure wave weakens rapidly with distance (inverse cube), whereas fragments keep their wounding power much further (inverse square), so fragment wounds are seen far from the blast.

Special problems in disasters

Crush injury and crush syndrome

• Crush syndrome: prolonged compression of muscle, then release → reperfusion, rhabdomyolysis, myoglobinuria, hyperkalaemia, acidosis, hypovolaemia and acute kidney injury. Seen in earthquake and building collapse survivors.
• Treatment starts before extrication: IV access and aggressive saline (Bailey & Love: about 1–1.5 L per hour in adults), catheter for urine output, then a mannitol–alkaline diuresis keeping urine pH above 6.5 until myoglobin clears. Watch potassium; dialysis if needed.
• Late fasciotomy of a compartment that has obviously died (trapped for over about 12 hours) releases more myoglobin and invites infection; it is best avoided.

Compartment syndrome

• Rising pressure in a fascial compartment (fracture, crush, tight cast, reperfusion).
• Pain out of proportion, especially on passive stretch, is the key early sign; pulses are usually still present.
• Treatment: remove tight dressings; early fasciotomy if in doubt. Untreated → Volkmann ischaemic contracture.

Infections

• Tetanus (Clostridium tetani, soil): give tetanus toxoid for contaminated wounds, plus human anti-tetanus immunoglobulin for heavily contaminated or cavitating wounds in those not fully immunised. Treat established tetanus with debridement, high-dose penicillin, large-dose immunoglobulin, diazepam for spasms, and ICU ventilation if spasms persist.
• Gas gangrene (Clostridium perfringens): crepitus, rapidly spreading toxic myonecrosis. Radical excision, high-dose penicillin (with clindamycin), and amputation if needed; stumps are left open.

Limb salvage

• Severity scores such as the Mangled Extremity Severity Score (MESS) help decide between salvage and amputation.
• Traumatic amputation stumps are trimmed and left open; definitive amputation level is chosen later.

Other

• Hypothermia and frostbite (rewarm gently; let dead tissue demarcate before surgery), dehydration, outbreaks of diarrhoea, measles and skin infections in camps, and psychological trauma.

Quick revision

• Multiple casualties: worst first. Mass casualties: best chance with least resources first.
• Triage is done by a senior and repeated; red immediate, yellow urgent, green minor, black dead, expectant separate.
• START red: RR over 30, refill over 2 s, cannot obey commands.
• Blast: 1 pressure (eardrum, lung, bowel), 2 fragments, 3 thrown, 4 burns, 5 additives.
• Commonest primary blast injury: tympanic membrane rupture.
• KE = ½mv²; temporary cavity explains hidden damage; marked above 600 m/s.
• War wounds: debride, fasciotomy, external fixation, leave open, re-look 24–48 h, close days 4–6.
• Crush syndrome: fluids before extrication, alkaline diuresis, avoid late fasciotomy.

Written by The House Job from standard references (Bailey & Love's Short Practice of Surgery, 27th edition; ATLS Student Course Manual, 10th edition).

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