Recognizing -A Case Study

Mary Black Johnson, PhD, ATC Mark Haines, MA, ATC Brian Barry, MA, ATC Metropolitan State College Assistant Athletic Trainer The Jim Davis Connection Denver, Colorado San Diego State University Carlsbad, California

9%-neumothorax injuries are to expand fully within its own position and air is expired from infrequent but can be life threat- pleural sac. the . The passive expiration ening. They are most often associ- During inspiration, the dia- process becomes active and is facili- ated with blunt trauma of the phragm contracts and flattens tated by contraction of abdominal chest. The trauma causes rib frac- while the ribs are lifted by contrac- and chest muscles during exercise. ture, which in turn perforates the tion of the . pleural wall. Thus, air or gas accu- Thus, the negative pressure in- 9njuw Changes mulates in the and creases, resulting in air flow from in Respiration causes the lung to collapse. It is the atmosphere into the increased critical to recognize the signs and area of the lungs. When the chest wall is pierced, in symptoms of this condition in or- When the muscles involved in either an open or closed chest in- der to provide prompt and suc- respiration relax, the diaphragm jury, normal pressure gradients cessful treatment in what can be a returns to its dome-shaped resting are altered. The normal pressure medical emergency. , 1 fluid-filled balloon Dynamics , of Normal Breathing Within the thoracic cage, each lung resides in a separate com- partment, the pleural sac. Between the thoracic wall and the pleural sac is a thin layer of intrapleural fluid (Vander et al., 1985) (Fig- ure 1). In the normal chest the lungs thoracic remain expanded due to two wall intrapleural counteracting pressures: alveolar (pressure within the lungs) and intrapleural (pressure of the fluid in the pleural cavity surrounding the lungs) (Vander et al., 1985). Between breaths, when no con- traction of the diaphragm occurs, the pressure within the lungs is .-- ,, ,-,,"* eqdt~~atm~sphe~~i~-~-es~~re-~~-~~~~- while the intrapleural pressure is less than atmospheric pressure. This gradient creates a negative pressure situation that allows each

O 1996 Human Kinetics 42 AthZeEie DZWCCBToday November 1996 PNEUMOTHORAX (OPEN-THE CHEST WALL INJURY PERMITS AIR TO FLOW IN AND OUT OF THE PLEURAL SPACE ON THE AFFECTED SIDE)

TRACHEA AND SHIFTED AWAY FROM PNEUMOTHORAX

TRAUMATIC AIR HAS ENTERE HEART AND VESSELS IN RUPTURE OF PLEURAL SPACE THE CHEST WA COLLAPSED THE

PLEURAL SPACE FILLED WITH AIR

INHALATION: AIR ENTERS THE INJURED EXHALATION: THE AIR IS PARTIALLY SIDE, CAUSING COLLAPSE OF THE LUNG FORCED FROM THE AFFECTED SIDE AND SHIFT OF THE MEDIASTINUM AND PLEURAL SPACE AND THE MEDlASTlNUM HEART TOWARD THE UNAFFECTED SIDE SHIFTS TOWARD THE AFFECTED SIDE

difference between alveolar and within the pleural space, but out- Types a$fPne~msthora intrapleural pressure is elimi- side the lung, reduces the air vol- nated. The resultant air in the in- ume capacity of the lung and trapleural space causes lung decreases its ability to accept and Most cases of pneumothorax are collapse and unilateral chest wall transport oxygen (Thomas, 1993) simple and closed. Generally expansion. The presence of air (Figure 2). caused by a blunt blow to the chest, 90% of all cases of traumatic closed pneumothorax observed in adults are the result of rib fractures (Zuidema et al., 1979), although closed pneumothorax following % Pleural cavity Degree of lung blunt chest trauma may occur Size occupied by air collapse - - without a rib fracture. The sever- Small 15% or less Minor ity of pneumothorax is classified by the volume of pleural space Medium 15-60 % Moderate occupied by air and the degree Large 60% or greater Severe of pulmonary collapse (Table I).