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We investigated the effects of head rotation on the cross-sectional area of the right internal jugular vein and its relative position to the carotid artery. Eighty-eight subjects were divided into infants and children groups. The cross-sectional area of the right internal jugular vein and the degree of the carotid artery overlap were measured at 0° (neutral), 40° and 80° of head rotation. The cross-sectional area of the right internal jugular vein was significantly larger at 40° and 80° head rotation compared with the neutral position in both infants and children (p < 0.001). As the head was rotated, the percentage overlap of the carotid artery increased significantly (p < 0.001). We suggest that 40° head rotation appears to be optimal for right internal jugular vein cannulation in paediatric patients.

Discussion

The development of severe neurologic dysfunction after surgery and anesthesia is rare in children and typically results from hypoxia, emboli, or hemorrhage in children with congenital heart abnormalities. The neurologic complication described here, however, occurred in a child without cardiac disease, and in the absence of hypoxia. The child was hypotensive for a 1-h period, but the recorded low blood pressure (50-70 mmHg) alone would not be expected to produce global cerebral ischemia. The complication seen in this child is thought to be the result of bilateral jugular venous occlusion combined with hypotension. The left IJV was occluded by the catheter-sheath in combination with a pressure dressing, whereas the right IJV was compressed after neck rotation by the invisible subcutaneous loop of the Broviac catheter.

Blood drains from the brain by two major routes: the jugular veins and vertebral venous plexus. The vertebral venous plexus is a major source of cerebral venous drainage only in the upright position, [1,2] and it is generally assumed that in the supine position, the jugular veins are the main cerebral venous drainage routes. It has been shown in animals that ligation of IJVs affects venous return from the cranial cavity and results in intracranial hypertension. [3] Similar events have been seen in humans. [4-6] It is likely that impairment of venous outflow is the main cause of these abnormal changes within the cranium. Further, impairment of venous return is likely to influence the reabsorption of cerebral spinal fluid possibly contributing further to intracranial hypertension and edema. [7] In the supine position, head rotation alone has an effect on IJV flow and increases the intracranial pressure (ICP), particularly with rotation 90 [degree sign] to the right. Because the left IJV often is smaller than the right IJV, there is a greater increase in ICP with head rotation to the right in patients with a baseline ICP greater than 10mmHg compared with that on head rotation to the left. [1,8] Studies using the range-gated Doppler technique have shown that rotation of the head 90 [degree sign] to the side completely obstructs jugular venous flow on that side. [8] Early recognition of jugular venous obstruction is necessary to avoid progressive cerebral injury.

The effect of head rotation on the diameter of the internal jugular vein: implications for free tissue transfer

Joseph Kamal Muhammada, f1, Neil David Pughb, Lucy Bodenb, St John Creana and Michael John Fardya

a Department of Maxillofacial Surgery, (Head: Professor, J. P. Shephera BDS MSc DDSc PhD FDSRCS), University Hospital Wales, Cardiff, UK

b Medical Physics and Bioengineering, (Head: Professor J. P. Woodcock BSc MPhil PhD CPhys FInstP, FIPEM, OBE), University Hospital Wales, Cardiff, UK

Received 16 June 2000; accepted 16 May 2001. ; Available online 12 March 2002.

Abstract
Purpose: To determine the effects of medial (inwards) and lateral (outwards) rotation of the head on the transverse diameter of the internal jugular vein. Material: The original study sample included 26 patients. Duplex ultrasound was used to measure the transverse diameter of the internal jugular vein at a fixed point on either side of the neck. Measurements were taken with the head central (neutral position), rotated laterally and medially. Results: Using Student's t -test we found that lateral rotation of the head produced a reduction in the mean of the transverse diameters of the left and right ipsilateral vein from 6.9 mm to 5.4 mm (p<0.03) and 5.9 mm to 5.0 mm (p=0.2173) respectively. One patient excluded from the study because of previous neck surgery showed complete occlusion of the ipsilateral internal jugular vein on lateral rotation of the head.
Conclusion: There is a possibility that patency of the vein could be compromised if the head is turned laterally. This situation may arise immediately after surgery in the ventilated and paralysed patient when the head may be unsupported. It could be of particular importance if the vein has been used as a recipient vein for free tissue transfer.

It is likely that impairment of venous outflow is the main cause of these abnormal changes within the cranium. Further, impairment of venous return is likely to influence the reabsorption of cerebral spinal fluid possibly contributing further to intracranial hypertension and edema.

American Journal of Neuroradiology, Vol 4, Issue 6 1219-1221, Copyright © 1983 by American Society of Neuroradiology


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ARTICLES


Effect of head turning on blood flow in lateral sinuses of nonhuman primates
TO Gabrielsen, LG D'Alecy, JE Knake, PG Hildenbrand and SS Gebarski


The pattern of blood flow leaving the cranium via the lateral sinuses and internal jugular veins is significantly altered by head rotation. This effect is documented in the baboon and macaque monkey by Doppler flow recording and by angiography. This phenomenon may affect the validity of cerebral blood flow data determined by venous sampling and may have significance in angiographic interpretation and in the clinical course of patients with a hypoplastic or occluded lateral sinus or internal jugular vein.

Rotation of the head to one side causes obstruction
of the ipsilateral internal jugular vein in most
anaesthetized and many nonanaesthetized children,
and may cause intracranial venous stasis.

Valdueza and colleagues[45] used color-coded duplex sonography to measure cerebral venous outflow in 23 healthy human volunteers, and found that internal jugular flow decreased from 700 mL/minute in the supine position to 70 mL/minute at 90° elevation. They also found a corresponding increase in vertebral vein flow from 40 mL/minute at 0° elevation to 210 mL/minute at 90°, with the remainder of the unmeasured flow probably passing through the internal vertebral venous plexus, which was inaccessible to Doppler measurement.