A 22-year-old male has an external ventricular drain placed for intracranial pressure monitoring following a traumatic brain injury. The patient continues to have a poor neurologic examination. There are episodes of time when he has an elevation in his intracranial pressure to 20 mm Hg that will last for 10 to 20 minutes at a time. During this time there are no changes to other vital signs. A tracing of the external ventricular drain (EVD) is shown below.
What is the phenomenon depicted?a. Lundberg A wave
Correct Answer: A
The intracranial pressure (ICP) waveform shown is the Lundberg A, which are a sustained elevation in ICP with amplitude of 50 to 100 mm Hg (higher than Lundberg B and C waves). They typically last for 5 to 20 minutes and they are always pathological as they represent reduced cerebral compliance and increase intracranial pressure. Lundberg B waves are short elevation of ICP with amplitude of 5 to 20 mm Hg at a frequency of 0.5 to 2 waves/min, which last for 1 to 5 minutes. They are thought to be normal waves with probably some association with unstable ICP and vasospasm. Lundberg C waves are rapid oscillations of 4 to 8 waves/min with low amplitude of <20 mm Hg. They are normal waves with changes related to cardiac and respiratory cycles. Without changes in other physiologic parameters, it is unlikely the ICP change is due to autonomic storming. Common features include increase in blood pressure, respiratory rate, heart rate, worsening level of consciousness, muscle rigidity, and hyperhidrosis.