What`s
Chest Trauma; Significant Source of Morbidity and Mortality

 

  

Muhammad Saaiq*
Muhammad Zubair**
Ikram Ullah**
Syed Aslam Shah***

Ann. Pak. Inst. Med. Sci. 2010; 6(3): 172-177

Background :Despite advances in trauma management and critical care, chest trauma still continues to be a significant source of morbidity, mortality and hospitalization especially in otherwise healthy young adults. 1-3   In  the developed countries, chest trauma  directly  accounts  for  20%-25%  of  all  trauma  related  deaths and  is recognized as  a  major  contributor in another  25%  of   trauma related  deaths. The mortality and morbidity depends on factors such as severity of chest injury, condition of the underlying lungs, associated extra-thoracic injuries especially to head, abdomen and long bones. 4,5  Road traffic accidents (RTAs),  firearm injuries (FAIs), falls from heights,  blasts,  stabs  and  other  acts  of  violence  are the causative  mechanisms involved. 1,4-6  
The clinical presentation varies from case to case, however there is more frequent involvement of the relatively young males, which further amplifies the grave implications of  this serious problem. 1, 7-9 In urban areas the problem stems largely from blunt mechanisms such as RTAs, falls from heights and accidents at construction sites. Stabs and FAIs are relatively more common in rural set ups.

RELEVANT ANATOMY AND PHYSIOLOGY: Chest trauma implies trauma to different structures of the chest wall and  the chest cavity. The chest is arbitrarily divided into four components including chest wall, pleural space, lung parenchyma and mediastinum. The chest wall includes the bony thorax and associated musculature. The pleural space lies between visceral and parietal pleura and can become filled with blood or air following chest trauma. The lung parenchyma includes the lungs and associated airways and may sustain contusions, lacerations, hematoma and pneumatocele. The mediastinum includes the heart, aorta/ great vessels of chest, tracheobronchial tree and esophagus. 4-6
Normally the chest is responsible for the vital   cardiopulmonary physiology of   delivering oxygenated    blood to the   metabolically active   tissues of the body.  Derangements  in  the flow of  air  or blood, either  alone or  in combination   are   responsible  for  the   pathologic consequences  of  chest  injury. Clinical   consequences of   chest  trauma  depend   on  factors such as the mechanism  of  injury, the  extent  and  location of injury, associated  injuries and underlying  co-morbidities. Chest trauma patients are likely to deteriorate due to effects on respiratory function with secondary associated cardiac dysfunction. Chest trauma treatment aims to restore cardiorespiratory function to normal, control of bleeding and prevention of sepsis. 10-12

INJURY MECHANISM: Chest trauma may   be   caused   by   blunt or  penetrating  mechanisms. 4, 5
Blunt Chest Trauma: Blunt   chest trauma accounts for about 75%-80% of all chest trauma cases and significant percentage of the patients have associated extra-thoracic injuries as well. RTAs   are the leading cause and account for up  to  80 % of cases in our country.  Falls from heights, assaults and  blast  injuries are the other  causative   mechanisms. The victims are usually young to middle aged men as they are more frequently in outdoor activities in road traffic, construction sites and other hazardous occupations. 1, 4
Blunt trauma to the chest causes injury by one of the three mechanisms; a   direct   blow   to   the   chest, deceleration   injury,   and compression   injury. 4
Penetrating chest trauma: Stab injuries, firearm injuries and blasts are the common causative mechanisms of penetrating chest trauma. These are further classified on the basis of the velocities of the penetrating missiles: 5

  1. Low   velocity injuries include knife cuts and impalements.
  2. Medium velocity injuries resulting from handgun and    air gun.
  3. High velocity injuries typically caused by   rifles    and military weapons.  These missiles produce their effects by causing temporary and permanent   cavitation     and   shock   wave  effects.
  4. Very  high  velocity  injuries  are caused  by  weapons  of  antipersonnel effects   e.g. mines,  blast   fragments, grenades and bombs. The   fragments may   have  a  velocity   of   4500   ft / sec.

Easy availability and indiscriminate use of weapons is a recognized cause of increasing penetrating trauma in our country. 8 Stab injuries and firearm injuries are often due to enmity and murder attempts.

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