To the Editor:— We congratulate Stocchetti et al. 1on their interesting case report and the favorable outcome of the patient. We agree with the authors that bilateral cannulation of internal jugular veins may worsen intracranial hypertension. Nevertheless, we wish to make some comments:
For internal jugular vein cannulation, their patient’s head and torso were placed in a flat position, and the head was even slightly rotated. All these procedures are known to increase intracranial pressure in patients with reduced intracranial compliance. 2In the context of increased intracranial pressure, we wonder why the internal jugular vein route was preferred for the insertion of the 8-French introducer and Swan-Ganz catheter to the subclavian or external jugular vein route.
In our opinion, Doppler or B-mode ultrasound guidance should always be used in these patients. Recently, we were able to demonstrate the safe cannulation even of the internal jugular veins in patients with reduced intracranial compliance under Doppler guidance without the need for change in body position. 3
Following the arguments of Stocchetti et al. that the introducer itself was responsible for the obstructed cerebral venous drainage, a B-mode ultrasound image of the left internal jugular vein should have shown a small-sized vessel. With regard to the high thrombogenicity of large-bore catheters in small-sized veins, another access route would have been preferred. 4In this context, we refer to a fatal incident of intracranial hypertension we encountered after tracheostomy. 5During neck extension, the patient experienced brain herniation due to obstruction of the accessory brain drainage pathway (vertebral venous plexus) in the context of unrecognized bilateral internal jugular vein obstruction (left: thrombosis after central venous cannulation; right: hypoplastic vein).
Blood drains from the brain by two major routes: the internal jugular veins and the vertebral venous plexus. 6,7Valdueza et al. 8have shown that predominance of the jugular veins in cerebrovenous drainage is limited to the supine position. When outflow through the internal jugular veins is compromised, the vertebral system becomes the major channel for blood leaving the cranium. 6
Various clinical implications, such as bilateral neck dissection, or metastatic spread of tumors, including the controversies about head positioning in increased intracranial pressure, underline the importance of a postural influence on cerebrovenous drainage. 8
In patients at risk, such as patients with reduced intracranial compliance, central venous access procedures should be performed under ultrasound guidance. 3
