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Uncontrolled intracranial hypertension remains an important cause of mortality and morbidity after severe brain injury. Controversies surrounding ICP treatment include the relative importance of lowering ICP or preserving CPP although the optimal level of CPP in severely brain injured patients is not known.

The determination of clearance of metabolites and oxygen in the brain is based on the assumption that a reliable sample of mixed venous blood can be drawn from the internal jugular vein (IJ) [1, 6, 7, 9]. In the current literature many measurements (AVDO2, CMRO2, etc.) are reported based on IJ samples drawn from either side of the neck. We compared oxygen saturation in both IJs in head injured patients to establish similarities or discrepancies in the two veins.

In comatose patients, monitoring of intracranial pressure has become a routine procedure. To prevent secondary cerebral ischemia, representing a major secondary insult to the traumatized brain [2, 4], it would be of the utmost importance to monitor cerebral blood flow, in addition. Measurement of cerebral blood flow in these patients is difficult to perform and limited to stochastic determinations. Recently, it has been demonstrated that the cerebral arteriovenous oxygen difference can be used to estimate cerebral blood flow [5, 6]. Moreover, it has become possible to continuously monitor cerebrovenous oxygen saturation by a fiberoptic catheter system [1, 3]. Such a system (Oximetrix 3) was used to continuously measure oxygen saturation in the jugular bulb of comatose patients to estimate cerebral blood flow and identify cerebral ischemia.

After head-injury cerebral metabolic rate (CMRO2) is reduced [2]. Cerebral blood flow (CBF) may be increased, normal or decreased. According to the Fick Principle, the relationship between global CMRO2 and CBF can be described by measurements of the arterio-jugular venous oxygen content difference (AJDO2). Thus, AJDO2 = CMRO2/CBF. The AJDO2 = Haemoglobin × 1.39 × (Arterial oxygen saturation — Jugular bulb venous oxygen saturation)/ 100. It is now possible to monitor the Jugular bulb venous oxygen saturation (SjO2) continuously using the “Oximetrix 3” system with a fibre-optic catheter placed high in the jugular bulb [1, 3]. If arterial oxygen saturation (SaO2), haemoglobin concentration and the position of the haemoglobin dissociation curve remain constant, SjO2 is proportional to CBF/CMRO2 · SjO2 above 75% represents luxury perfusion, while below 54% increased oxygen extraction signifies hypoperfusion [4]. This study examines the effects of both hypnotic and osmotic treatments of raised intracranial pressure (ICP) on cerebral perfusion pressure (CPP) and SJO2 after severe head injury.

Cerebral vasospasm (CV) is the leading cause of death and disability in patients with subarachnoid hemorrhage (SAH). We suppose that clinical vasospasm disturbances could be detected by the increase in cerebral oxygen extractions (AVDO2), so in this study we tried to predict clinical CV appearances using jugular bulb oximetry monitoring.

This study was performed to elucidate the anatomic variations of the jugular fossa (JF) on the basis of examination of 120 human temporal bones. Observations were made of temporal bones sectioned along a plane including the cochlea, the JF, and long axis of the internal auditory canal. The position of the upper margin of the JF was classified according to its relation to the tympanic cavity, the cochlea, and the internal auditory canal. The height of the upper margin of the JF was classified as follows. Low type; inferior to the level of the external auditory canal. Middle type; between the level of the external auditory canal and the cochlea. High type; superior to the level of the cochlea. The results revealed that 58 ears were of low type, 46 middle type, and 16 high type. Middle and high type comprised 62 ears, thus in 52% of ears the upper margin of the JF was situated superior to the external auditory canal. The relation between the JF and the cochlea was classified as follows. Medial type; medial to the medial margin of the cochlea. Lateral type; lateral to the medial margin of the cochlea. The results showed that 74 ears were of medial type, and 46 lateral type. Therefore, in 62% of ears the upper margin of the JF was situated medial to the medial margin of the cochlea. Forty-seven ears of medial type were of middle or high type. Ears of lateral type included none of high type. The jugular bulb diverticulum was observed in 32 ears, which consisted of 3 of low type, 13 middle type, 16 high type. When the upper margin of the JF was positioned higher, the JF was in a more medial position. However, no defect of the bony labyrinth was observed. In conclusion, it is considered that protrusion of the jugular bulb into the tympanic cavity was not caused by the abnormally high position of the JF, but by its lateral displacement. Distances from the JF to the surrounding structures were as follows; to the tympanic membrane 5.58 +/- 2.43mm (mean +/- S.D.), to the tympanic cavity 2.94 +/- 1.92mm, to the cochlea 4.93 +/- 2.20mm, and the internal auditory canal 5.82 +/- 2.38mm.

We have compared in vivo oxygen saturation recordings obtained from the Oximetrix 3 with in vitro measurements using the Instrumentation Laboratories 282 Co-Oximeter. The small mean difference (0.85%) and close limits of agreement (—4% to 6%) are close enough for clinical purposes, provided in vivo calibration is performed after insertion of the fibreoptic catheter and repeated at least every 12 h. Continuous monitoring of jugular bulb oxygen saturation during intensive care of brain injured patients is now possible using fibreoptic technology. This technique may be of value in detecting global ischaemia, and as a predictor and monitor of cerebral perfusion pressure therapy.

We have modified the transcochlear approach to improve exposure of the anterior petrous apex, clivus, anterior cerebellopontine angle, and the prepontine region. These changes include resection of the external auditory canal, middle ear, glenoid fossa, and posterior zygomatic arch. This approach provides improved exposure of the petrous carotid artery, jugular bulb, and clivus. It offers the largest and most lateral access to the anterior cerebellopontine and prepontine region. The results of this approach in 11 patients are discussed.

Jugular bulb diverticula may extend either laterally in the tympanic cavity or medially towards the petrous pyramid close to the inner ear. In the first case, this leads to subjective symptoms related to the presence of a mass at the level of the tympanic cavity and the external auditory canal and thus to conductive hearing loss and pulsatile tinnitus. In the second case, vertigo, pulsatile tinnitus and sensorineural hearing loss occur. 4 cases of jugular bulb diverticula are described (1 medial type, 3 lateral type). © 1991 S. Karger AG, Basel.

The main objective in neurointensive care is to restore or maintain cerebral homeostasis as a prerequisite for neuronal survival and recovery of neurologic function. Clinical examination provides only late information about cerebral deterioration. Since brain function is exquisitely dependent upon adequate oxygen (O2) delivery, monitoring of cerebral O2 availability and utilization has become an important challenge for clinicians caring for patients with brain insults or who are at risk for oxygen deprivation. The availability of continuous measurement of O2 saturation in the jugular bulb (SJO2) raises the question of the value of this parameter as an index of brain oxygenation in clinical practice.

Septic thrombosis of the transverse-sigmoid sinuses and the jugular bulb is a highly lethal condition. The presenting signs and symptoms of this disease entity are subtle and not in proportion to the magnitude of the problem. Later in the disease course, sudden fulminant findings appear. A high index of suspicion, combined with scanning techniques of either enhanced MRI or CT, allows prompt diagnosis and treatment. MRI enhanced with gadolinium-DTPA (Gd) is a valuable adjunct that confirms the diagnosis and delineates the extent of suspected pathology.

• Traditionally, jugulotympanic tumors, also called chemodectomas or paragangliomas, have been evaluated by conventional imaging to show bone erosion and angiography for the definitive diagnosis, location, and extent. More recently, computed tomography has been used to show these features as well as the intracranial extension. Magnetic resonance imaging has added a new dimension, particularly for assessment of intracranial spread and growth downward into the neck. We examined 20 jugulotympanic glomus tumors by computed tomography and magnetic resonance imaging with gadolinium enhancement and believe that these two imaging modalities, combined with clinical assessment, can provide all the necessary information regarding diagnosis, situation, and extent in the majority of jugulotympanic glomus tumors. Godolinium-enhanced magnetic resonance imaging was particularly effective for the detection of small tumors confined to the middle ear and for confirmation that the jugular bulb was not involved. Consequently, angiography is no longer a first-line imaging investigation but rather a preoperative evaluation only in those tumors in which preoperative embolization is required or occasionally when the extent of the tumor, especially in the jugular bulb, cannot be confidently predicted by noninvasive imaging. ( Arch Otolaryngol Head Neck Surg . 1990;116:940-945)

Cholesterol granulomas of the petrous apex are drained through two major extralabyrinthine routes: one, along the posterosuperior chain of air cells, and two, along the anteroinferior chain. Procedures that use the posterosuperior chain approach the apex from the sinodural angle, the base of the zygomatic arch, the attic, or through the arch of the superior semicircular canal. Operations that use the anteroinferior chain reach the apex along the internal carotid canal (Ramadier's operation) or by a posterior infralabyrinthine approach between the descending facial nerve and jugular bulb. Inferior petrous apex cholesterol granulomas may be unreachable by any of these routes, and hence the subcochlear route is proposed as an alternative. The subcochlear approach starts in a triangle bounded superiorly by the cochlea, anteriorly by the internal carotid canal and posteriorly by the deep jugular vein. This operation requires lowering the inferior bony canal wall to the level of the "crutch." It provides access to an inferiorly situated cholesterol granuloma, yet preserves hearing. It allows enough room for the placement of a tube drain from the petrous apex to the mastoid. It is particularly useful when a high jugular bulb precludes the use of the posterior infralabyrinthine route.

It has been well established by anatomic and tomographic reports [1, 2] that the endolymphatic sac (ELS) and vestibular aqueduct (VA), appear in great varieties of size, position, course, and form. These irregularities are particularly pronounced in Meniere’s disease, with tomographic studies revealing the VA to be filiform, stenotic, or nonvisualized in more than 50% of all Meniere’s cases [3, 4]. Such tomographic findings were used by Stahle and Wilbrand [4, 5] in the development of a system classifying the degree of peri-aqueductal pneumatization in Meniere’s disease into 3 grades: large cell pneumatization, small pneumatization, and non-pneumatization.

A ten-year-old male presented with non-specific head-aches without focal findings. A post-contrast CT incidentally revealed bilaterally superiorly and laterally placed jugular bulbs within the petrous bones, symmetrically

A high jugular bulb is not an uncommon otologic anomaly. It may be noted as an incidental finding on physical exam, middle ear surgery, or computed tomography of the temporal bones. Frequently the patient is asymptomatic, but a high jugular bulb can occasionally cause tinnitus or conductive hearing loss. The case of a seven-year-old black male with unilateral conductive hearing loss secondary to a high jugular bulb is presented. The diagnosis, differential diagnosis, and management of a conductive hearing loss associated with a high jugular bulb are discussed.

86 Comparison Between Cerebral Tissue Oxygenation Index Measured by Near- Infrared Spectroscopy and Venous Jugular Bulb Saturation in Children

Neurological monitoring is very important to change the prognosis of a critical neurological patient. The jugular venous bulb saturation is extremely important to evaluate the consumption and delivery of oxygen.

Procedures and Monitoring for the Critically Ill is a multi-authored manual, detailing 29 procedures and monitoring techniques used in intensive care. This is an expedient, introductory critical care reference, particularly for physicians in training. The topics are pragmatic, describing common procedural topics for intensive care. Typically, each area has an effective description of the methods and illustrations of the techniques. A bibliography of key references accompanies each chapter. Succinct descriptions of step by step methods as well as the required supplies are included for 1) hemodynamic monitoring (e.g., central venous pressure, pulmonary artery catheterization, arterial catheterization); 2) neurologic monitoring (e.g., intra-cranial pressure monitoring, jugular bulb oximetry); 3) trauma related areas (e.g., spinal immobilization, intra-abdominal pressure monitoring, abdominal paracentesis; 4) emergency airway support (e.g., endotracheal intubation, cricothryrotomy, bronchoscopy, and tracheostomy); as well as 5) other areas including transesophageal Doppler monitoring, epidural analgesia, renal support, and inferior vena cava filter placement. For greater detail in ICU monitoring procedures, interested readers are recommended to more encyclopedic texts, such as Principles and Practices of Intensive Care Medicine, edited by M.Tobin. In summary, this text is a useful reference during the preliminary years of training for critical care or rapid review of methodologies of ICU procedures and monitoring techniques.

Disturbances of the cerebral circulation play a key role in the pathophysiology of head injury. TCD ultrasonography, a non invasive bedside technique, and SjO2 monitoring, an invasive technique which has some risk factors, are methods of assessing cerebral hemodynamics. The purpose of the study was to examine the relationships between TCD parameters and SjO2 measurements in patients with head injury.

Introduction. Catheterization of the jugular bulb is of great value in the study of cerebral metabolism, since it permits diagnosis of episodes of hypoxia and cerebral ischaemia. Objectives. To determine the frequency of the appearance of episodes ofdesaturation and cerebral ischaemia, whether these were simultaneous and their relation to the mortality in an intensive care unit (ICU), Patients and methods. We studied 21 neurocritical patients, recording the following data: age, sex, diagnosis and state at the time of discharge from the ICU (alive or dead). In the group of patients in whom the jugular bulb had been catheterised we also recorded: the side cannulated, complications, SyO 2 , cerebral lactate-oxygen index and modified cerebral lactate-oxygen. Results. In 57% of the patients we catheterised the jugular bulb and in 50% of them at least one episode of desaturation was recorded, and cerebral ischaemia in 42%. Only one patient had simultaneous desaturation and cerebral ischaemia. Of the six patients in whom desaturation was detected, 5 died in the ICU (83.3%). The mortality of patients with ischaemia was only 40%. 40% of the patients with head injuries were monitored and 50% of the non-monitoredpatients had head injuries. Conclusions. Episodes of desaturation are frequent in neurocritical patients and are associated with increased mortality. Recordings of lactate are not useful at present in the diagnosis of cerebral ischaemia.

Jugular bulb oxyhaemoglobin desaturation (SjO2≤ 50%) during the rewarming phase of cardiopulmonary bypass (CPB) is associated with postoperative cognitive deficits [1]. Isoflurane effects cerebral blood flow and cerebral metabolic rate, both of which affect SjO2 [2]. We report the effect of isoflurane on the incidence of desaturation during rewarming from CPB for coronary artery surgery.