Which of the following statement(s) is/are true concerning injuries to the chest wall?

c. In most cases of an open pneumothorax, or sucking chest wound, surgical closure is necessary

d. Persistent chest tube bleeding at a rate greater than 200 ml/hour for four hours, or greater than 100 ml/hour for eight hours is an indication for thoracotomy for control of hemorrhage 

e. A 20% incidence of splenic injury is associated with fractures of ribs 9, 10 and 11 on the left

Rib fracture is the most common injury associated with blunt chest trauma and may occur directly at the site of force or laterally as the result of significant antero-posterior compression of the chest. The location area of the rib fracture may be indicative of associated injuries. A 20% incidence of splenic injury is associated with fracture of ribs 9, 10, and 11 on the left with a similar association with right lower rib fractures and hepatic parenchymal injuries. The mortality rate associated with sternal fractures in older series was as high as 25–30%, mainly because of other injuries to the chest, such as aortic transection, cardiac contusion, tamponade or tracheo-bronchial rupture. More recent studies have suggested a change in the pattern and severity of injuries associated with sternal fracture. Widespread improvements in automobile safety have likely contributed to this change such that isolated sternal fractures may result from shoulder belt use and may not necessitate hospital admission in the stable patient. A flail chest occurs when consecutive ribs are fractured in more than one place, creating a free-floating segment of the chest wall. The creation of a free-floating segment may result in paradoxical chest wall motion with respiration. The intact chest wall expands during inspiration, but the negative intrathoracic pressure generated causes the flail segment to move inappropriately inward. Historically it was believed that the paradoxical motion was the cause of severe ventilatory insufficiency associated with the flail chest. Gradually, understanding of the pathophysiology of the flail chest has evolved. The ventilatory impairment is not simply due to paradoxical motion of the chest wall, but rather due to underlying pulmonary parenchymal injury in combination with the hypoventilation and splinting that results from the pain of multiple contiguous rib fractures. The open pneumothorax, or sucking chest wound, is an uncommon injury usually caused by impalement, high-speed motor vehicle accident, or shotgun blast, which causes a large chest wall defect. The diagnosis of a sucking chest wound can be made on simple inspection of the chest wall and hearing the flow of air through the wound. The defect should be occluded immediately with an impermeable dressing, essentially converting the situation to a closed pneumothorax. Tube thoracostomy is then performed to re-expand the lung. The chest wall defect usually requires operative debridement and formal chest wall closure. A hemothorax is the accumulation of blood in the pleural space and it occurs in 50–75% of patients with severe blunt or penetrating chest trauma. Massive hemothorax (i.e., larger than 1000– 1500 ml) may require thoracotomy. Persistent bleeding, at a rate of > 200 ml/hour for four hours, or > 100 ml/hour for eight hours, is also an indication for thoracotomy. If the patient manifests any hemodynamic instability during the period of observation, urgent thoracotomy is mandatory.