Transcript
CHAPTER 18 </P></ANS></ANSSET></MCQSET>
Clinical Reasoning Checkpoint Answers
Mr. R., a 45-year-old male, is brought into the emergency department following a motor vehicle crash where he was an unrestrained driver. He was ejected from his vehicle after he lost control and hit a large tree. Emergency personnel arrived and found Mr. R. lying on the ground, disoriented and combative, with a GCS of 14. As the EMTs were trying to calm him, he suddenly lost consciousness. His left pupil was 4 mm with sluggish reactivity. His right pupil was 3 mm and briskly reactive. His GCS was now 7. He was intubated and transported to the ED, where he suffered a seizure upon arrival. His pupils were still unequal, with right being 4 mm and left 6 mm and both sluggish to light. His BP was 135/80 and HR was 60/minute. His ventilator was delivering his breaths at an assist control mode at a rate of 16 breaths per minute.
1. Based on your initial assessment so far, what health problem, if any, do you suspect? Explain why.
Answer: Because he was an ejected driver, this increases his risk for TBI. His symptoms are suspicious for epidural hematoma, especially because he was conscious, then became unconscious; however, he may also have other TBIs such as SDH, SAH, and DAI; his seizure is likely a result of a head injury; it is troubling that his HR is only 60. It is not known whether he takes medications or if he has a seizure disorder; he may also have suffered a skull fracture or some other internal injury.
2. What diagnostic test would be indicated for Mr. R. at this time?
Answer: A CT scan is indicated to determine whether he has suffered a TBI or spinal cord injury. It would be very important to immobilize him for transport.
Clinical Update: Mr. R. was sent for a CT scan, which revealed a left subdural hematoma (SDH); a small left temporal subarachnoid hemorrhage (SAH); a left temporal nondepressed skull fracture; and a left linear basilar skull fracture. He was transferred to the OR for evacuation of his subdural hematoma and then admitted to the neurosurgical ICU. While on mechanical ventilation his arterial blood gas was pH 7.34, PaCO2 45, PaO2 188.
3. What aspects of his ABG might contribute to an increased ICP?
Answer: His PaCO2 is 45, which is at the high end of normal. PaCO2 should be maintained at 35–40. It is also needed to maintain pH at normal levels (7.35–7.45). Hypercapnia and acidosis contribute to cerebral vascular vasodilation, which increase ICP. Intracranial hypertension impairs CPP.
Clinical Update: Mr. R.’s vital signs are stable: HR 98 (NSR), respiratory rate 18, BP 120/72, temperature 97.0°F, ICP 12, with a CPP of 76–80. You note that he has bilateral periorbital ecchymosis (raccoon eyes). After 2 hours, he becomes agitated, able to localize to pain without eye opening and no verbal response due to intubation. His pupils are now 4 mm and briskly reactive to light bilaterally.
4. What is the patient’s current Glasgow Coma Scale?
Answer: 7T (where T indicates that he is intubated)
5. What should the nurse monitor frequently?
Answer: Vital signs; GCS and neuro assessments; signs of CSF leak, such as rhinorrhea; signs of seizure activity; pain and sedation control. ICP and CPP will also need to be monitored. Hypotension and hypoxia will require immediate intervention to avoid secondary injury.
Clinical Update: Now 24 hours later, Mr. R begins to have episodes where his ICP increases to 32 and his CPP is 54. An external ventricular drain is placed.
6. What initial nonpharmacologic nursing interventions should be tried to reduce his ICP?
Answer: First-level interventions to reduce elevated ICP include patient positioning strategies to prevent constriction of venous outflow from the brain. Patients should be positioned with the head of the bed elevated 30 to 45 degrees, avoiding hyperextension, flexion, or rotation of the head and neck. Reverse Trendelenburg’s position may be helpful as well as ensuring that there is no constriction of jugular veins from endotracheal tube tape, ties, or cervical collars. Also, reducing environmental stimuli may help to control ICP.
7. What is the benefit of the ventricular drain? What additional interventions could be used to help control his ICP?
Answer: A ventricular drain allows drainage of CSF to reduce ICP. Medical interventions for the treatment of severe, refractory intracranial hypertension that does not respond to conventional therapeutic measures include the use of high-dose barbiturates to induce a coma, which reduces metabolic demands, cerebral oxygen requirements, and controls seizure activity, thus reducing ICP. This therapy requires the patient to be on mechanical ventilation and vasopressors. Surgical intervention may include decompressive craniectomy.
8. What are potential complications of traumatic brain injury?
Answer: Complications associated with TBI include diabetes insipidus, syndrome of SIADH, cerebral salt wasting, seizures, and herniation.
