COMBINED RADIATION INJURIES

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COMBINED RADIATION INJURIES
Module XIV
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Introduction-effects of nuclear bomb and nuclear
accident

• The detonation of atomic bombs over Hiroshima
  and Nagasaki on 6 9 August 1945

Chernobyl nuclear reactor accident on 26 April
1986
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Classification

• According to radiation dose combined with other
  factors, CRI can be classified as
• thermal CRI external/internal irradiation with
  thermal burns
• mechanical CRI external/internal irradiation
  with wound or fracture, or haemorrhage
• chemical CRI external/internal irradiation with
  chemical burns or chemical intoxication

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Predicted distribution of injuries from
nuclear explosion

• Single injuries 30 to 40
• Ionizing radiation
• (including fallout) 15 to 20
• Burns 15 to 20
• Wounds Up to 5

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Predicted distribution of injuries from nuclear
explosion

• Combined injuries 65 to 70
• Irradiation, burns, wounds 20
• Irradiation, burns 40
• Irradiation, wounds 5
• Wounds, burns 5

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Medical Management

• Triage
• Emergency care
• Definitive care

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Triage

• In radiation accident or nuclear detonation, many
  patients can suffer from burns and traumatic
  injuries in addition to radiation
• Initial triage of combined injury patients based
  on conventional injuries
• Treat associated injuries first

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Emergency procedures

• First actions standard emergency medical
  procedures
• Ventilation
• Circulation
• Stop haemorrhage
• Decontamination after stabilization
• Survivable radiation injury not acutely life
  threatening

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Secondary assessment of combined injury

• Primary surgical responsibilities
• Stabilize
• Set surgical priorities
• Perform surgery
• Secondary responsibilities
• Manage post-operative course
• Assess radiation exposure in post-operative or
  post-stabilization period

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Prognosis

• Prognosis for all combined injuries worse than
  for radiation injury alone
• Infections much more difficult to control
  wounds and fractures heal more slowly

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Burns and radiation
Boy was 1.5 miles from the detonation of the
Nagasaki atomic bomb
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Radiation and burns
Radiation burns on Japanese atomic bomb victim
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Sytemic response to major burn injury

• Early period
• Shock with hypovolemia
• Gastrointestinal ileus
• Oligouria

• After adequate resuscitation
• Hyperdynamic state
• Increased cardiac output
• Diuresis
• Peripheral catabolism

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Causes of burn deaths

• Direct results of accident 13
• Sepsis
  45
• Organ /system failure
• (burn shock, acute renal failure) 41
• Iatrogenic intervention 1

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Expected mortality from thermal injuries
Burn area ( of body surface area) Expected mortality
gt 30 100
10-30 Survive with specific treatment
lt10 Survive even without treatment
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Combined effects of simultaneous whole body
irradiation and burns on rats
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Burn therapy

• Topical antimicrobials
• Early grafting
• Stimulation of the bone marrow and possibly of
  skin regeneration with cytokines

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Principles of controlling infection in burn care

• Use antimicrobials
• Support immune mechanisms
• Eliminate infection reservoirs
• Suppress infection transfer

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Suggestions

• Full thickness burns ideal bacterial culture
  media - excise and graft
• Make no change in indications for escharotomy
• Partial thickness burns could be treated with
  aggressive topical therapy avoid nosocomial
  sepsis

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Initial surgery
Major skin necrosis on both legs, extending to t
subcutaneous tissue
Complete graft healing after 8 days
Epifascial excision of necrotic skin
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Treatment of Contaminated Burn Injuries

• Gentle decontamination after stabilization
• Passive tetanus immunization even in previously
  immunized patients

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Chernobyl victims - classification
 
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Chernobyl conclusions

• Radiation burns frequent
• Burns over 50 of body surface led to death in 19
  out of 28 cases
• Internal contamination was present in most of
  patients, however, it was significant just in a
  few cases.
• Sepsis uniform cause of death
• BMT very limited indications
• Some radiation burns did not re-epithelialize and
  required surgery

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Wounds and radiation
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Trauma repair
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Effects of persistent pancytopenia

• Decreased oxygen capacity
• Lack of release of new erythrocytes and aging of
  red cell population
• Decreased clotting ability
• Megakaryocytes unable to replicate, plateletes
  consumed
• Altered wound healing
• Fibroblasts damaged by irradiation do not
  replicate at normal rate
• Immunosuppression

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Combined injury immunological effects

• Bone marrow suppression
• Consumption of inflamatory reserves
• Disruption of epidermal barriers
• Depression of reticuloendothelial system

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Experience from Hiroshima and Nagasaki patients

• Complications developed 2 to 3 weeks after
  exposure characteristic of bone marrow depression
  effects
• Open wounds stopped healing, haemorrhaged
• Many patients died of sepsis

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Wound problems

• Wound colonization
• Failed delayed primary closure
• Wound sepsis
• Delay in healing
• Occasional amputation
• Radiologically contaminated wound

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Treatment

• Control haemorrhage
• Debride extensively
• Repair vital structures
• Irrigate
• Consider wound closure

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Timing of surgical management
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Combined radiation injuryReview-I

• Diagnosis, treatment and prognosis are much more
  complex in CRI
• Haematological indices and other laboratory tests
  can be modified in a way that makes diagnosis of
  radiation component difficult

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Combined radiation injuryReview-II

• Because radiation injury is not immediately life
  threatening, initial care should address
  emergency medical procedures for ventilation,
  perfusion and treatment of haemorrhage

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Combined radiation injuryReview-III

• Patients with multiple injuries complicated by
  radiation injury require more aggressive
  treatment than non-irradiated patients
• Combined injury requires all urgent surgery to be
  completed within 48 hours of irradiation