Regarding hanging injuries, which ONE of the following statements is INCORRECT?
Answer: D: Hanging occurs when pressure is exerted on the neck and then tightened by the weight of the victim’s body. Complete hanging refers to when the body is suspended but the feet do not touch the ground. Incomplete hanging refers to all other positions of the body, when the feet are in contact with the ground. The mechanism of death usually differs depending on the method of hanging. When a victim falls from a height equal or greater than his or her height and the knot is anteriorly placed, death usually results from a fracture of the cervical spine at C2 (Hangman’s fracture) and transection of the spinal cord. If a hanging is incomplete or the victim drops a distance less than his or her height, the cervical spine is spared. In these circumstances, death is usually due cerebral anoxia from venous and arterial occlusion or bradycardic cardiac arrest from carotid stimulation. Tracheal compression is unlikely to cause death as other immediately acting mechanisms overtake this as the cause of death.
In hanging injuries venous infarctions in the brain are common and care should be taken during resuscitation not to further compromise the venous return by interventions around the neck.
References:
Regarding the diagnosis and management of haemothorax in patients with thoracic trauma, which ONE of the following statements is TRUE?
Answer: B: Haemothorax is a frequent finding in patients with both blunt and penetrating thoracic trauma. Massive haemothorax is a life-threatening injury and detection is vital during the primary survey. It is defined as >1500 mL of blood in the hemithorax or blood occupying approximately two-thirds of the available space in the hemithorax. During the primary survey, while excluding other life-threatening chest injuries, any evidence of a massive haemothorax should be looked for. These include absent chest movement, reduced or no breath sounds and dullness to percussion on the affected side.
On a supine CXR even >1000 mL of blood in the hemithorax can be missed due to posterior layering of blood. However, bedside USS has a higher sensitivity and similar specificity compared with CXR in detecting a haemothorax in a supine patient and can show the layering of blood posteriorly.
Haemothorax is most frequently caused by bleeding from direct lung injury, with several local factors playing a role in limiting bleeding from torn lung parenchyma. This could be a possible reason for <5% of the admitted patients with chest trauma requiring tube thoracostomy. Massive haemothoraces are often caused by arterial bleeding from pulmonary, intercostal and internal mammary arteries and almost always require invasive management. Venous bleeding usually tamponades without intervention.
While massive haemothorax requires urgent tube thoracostomy, small haemothoraces may be observed in the stable patient. Drainage may still be required if the patient is symptomatic. Haemothoraces of >300–500 mL should be removed as completely and rapidly as possible because large clots can act as a local anticoagulant, preventing cessation of bleeding from small intrathoracic vessels.
Regarding a patient with a flail chest secondary to blunt trauma, which ONE of the following statements is TRUE?
Answer: D: A flail chest is defined as a segment of the rib cage involving at least three adjacent ribs with fractures in two or more locations on each rib anteriorly or laterally. This segment of the chest wall moves paradoxically inward with spontaneous inspiration and outward during spontaneous expiration with associated increased work of breathing. The paradoxical chest wall movement may not be visible initially because of muscular spasms and splinting. However, as lung contusion develops and lung compliance falls, the paradoxical movement becomes more visible.
The reason for hypoxaemia in these patients is the associated underlying lung contusion. Although small flail segments without underlying lung contusion can be managed without mechanical ventilation, all high-risk patients should be considered for early intubation and ventilation as it is associated with reduced mortality compared with delayed intubation until the onset of respiratory failure. High-risk patients include flail segment involving eight or more ribs, patients >65 years of age and those with underlying lung disease.
Regarding traumatic pneumothorax in a spontaneously ventilated patient, all of the following are correct EXCEPT:
Answer: B: In a supine trauma patient, the USS seems to be more sensitive than a supine CXR in diagnosing a pneumothorax. A pneumothorax that is not visible on a CXR and incidentally found on a chest CT or abdomen can usually be managed conservatively without IC tube. However, if the patient is ventilated or likely to be requiring ventilation, an IC tube should be placed to prevent development of a tension pneumothorax. Stab wounds to the chest are notorious for producing delayed onset pneumothoraces, usually 4–6 hours from the time of injury. Therefore, when the initial CXR is negative for a pneumothorax and the patient is asymptomatic, the patient should be observed and the CXR repeated in 4–6 hours. When there is airflow obstruction as in COPD, it is more likely that more air will be pushed in to the traumatic pneumothorax form the alveoli, hence there is an increased likelihood of development of tension in such patients.
Reference:
Regarding pneumomediastinum caused by blunt chest trauma in an adult, which ONE of the following statements is TRUE?
Answer: A: One of the main concerns in managing patients with a traumatic pneumomediastinum is to exclude significant associated tracheobronchial and oesophageal injuries. Although rare, aerodigestive tract injuries are associated with significant morbidity and mortality; therefore, assessment should be directed at detecting these important injuries. In the majority of cases, pneumomediastinum is caused by either alveolar rupture, with dissection and coursing of free interstitial air towards the mediastinum along the connective tissues surrounding the bronchi and pulmonary vessels (Macklin effect), or by the direct extension of a pneumothorax into the mediastinum.
The features of pneumomediastinum include:
Electrical alternans is a feature of a large pericardial effusion.
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