The Internal jugular veins are asymmetric. Usefulness of ultrasound before catheterization

Guided wave elastography of jugular veins: Theory, method and in vivo experiment

Testing the mechanical properties of veins is important for diagnosing some cardiovascular diseases such as deep venous thrombosis. Additionally, it plays a crucial role in designing body protective products such as head protective gear, where simulations are necessary to predict the mechanical responses of bridging veins during head impacts. The data on venous mechanical properties reported in the literature have mainly been obtained from ex vivo experiments, and inferring the material parameters of veins in vivo is challenging. Here, we address this issue by proposing a guided wave elastography method in which guided waves are generated in the jugular veins with focused acoustic radiation force and tracked by an ultrafast ultrasound imaging system. Then, a mechanical model considering the effects of the perivascular soft tissues and prestresses in the veins was applied to analyze the wave motions in the jugular veins. Our model enables the development of an inverse method to infer the elastic properties of the veins from measured guided waves. Phantom experiments were performed to validate the theory, and in vivo experiments were carried out to demonstrate the usefulness of the inverse method in practice.

A framework of transient hypercapnia to achieve an increased cerebral blood flow induced by nasal breathing during aerobic exercise

During exercise, cerebral blood flow (CBF) is expected to only increase to a maximal volume up to a moderate intensity aerobic effort, suggesting that CBF is expected to decline past 70 % of a maximal aerobic effort. Increasing CBF during exercise permits an increased cerebral metabolic activity that stimulates neuroplasticity and other key processes of cerebral adaptations that ultimately improve cognitive health. Recent work has focused on utilizing gas-induced exposure to intermittent hypoxia during aerobic exercise to maximize the improvements in cognitive function compared to those seen under normoxic conditions. However, it is postulated that exercising by isolating breathing only to the nasal route may provide a similar effect by stimulating a transient hypercapnic condition that is non-gas dependent. Because nasal breathing prevents hyperventilation during exercise, it promotes an increase in the partial arterial pressure of CO2. The rise in systemic CO2 stimulates hypercapnia and permits the upregulation of hypoxia-related genes. In addition, the rise in systemic CO2 stimulates cerebral vasodilation, promoting a greater increase in CBF than seen during normoxic conditions. While more research is warranted, nasal breathing might also promote benefits related to improved sleep, greater immunity, and body fat loss. Altogether, this narrative review presents a theoretical framework by which exercise-induced hypercapnia by utilizing nasal breathing during moderate-intensity aerobic exercise may promote greater health adaptations and cognitive improvements than utilizing oronasal breathing.

Differentiation between anatomical slenderness and acquired stenosis of the internal jugular veins

Background and Purposes

Differentiating between acquired stenosis (pathologic) and anatomical slenderness (physiologic) of internal jugular vein (IJV) remain ambiguous. Herein, we aimed to compare the similarities and differences between the two entities.

Methods

Patients who underwent head and neck computer tomography (CT) and brain magnetic resonance imaging (MRI) were enrolled in this case‐control study from January 2016 through October 2021.

Results

1487 eligible patients entered final analysis totally. 803 patients had bilateral IJVs imaging without IJV stenosis‐related symptoms and presented in three ways: right IJV slenderness (10.5%, n = 85), left IJV slenderness (48.4%, n = 388), and symmetric IJVs (41.1%, n = 330). In patients with asymmetric IJVs, their bilateral jugular foramina were also asymmetric. All involved asymmetric IJVs presented as slenderness without surrounding abnormal collaterals and credible cloudy‐like white matter hyper‐intensity (WMH). Their cerebral arterial perfusion statuses on brain MR‐PWI maps were normal.

In contrast, the major patients with IJV stenosis presented with signs and symptoms such as headaches, head noise, etc. In CE‐MRV maps, local stenosis of the IJV was surrounded by abnormal venous collaterals in contrast to the lack of abnormal venous collaterals for patients with IJV slenderness. And in CTV maps, the caliber of jugular foramina was mismatched with the transverse diameter of IJV. Moreover, in MRI maps of most of these patients, a cloudy‐like WMHs were distributed symmetrically in bilateral periventricular and/or centrum semi vales. These patients also had symmetrical cerebral arterial hypo‐perfusion. Seven patients underwent stenting of the IJV stenosis correction, their WMHs attenuated or disappeared subsequently.

Conclusions

Imaging features in addition to clinical symptoms can be used to differentiate between physiologic IJV slenderness and pathologic IJV stenosis. Notable imagine‐defining features for IJV stenosis include local stenosis surrounded by abnormal venous collaterals, cloudy‐like WMHs, and mismatch between the transverse diameter of IJV and the caliber of the jugular foramina.

Dl-3-n-butylphthalide attenuates brain injury caused by cortical infarction accompanied by cranial venous drainage disturbance

Background

Cerebral venous disorder may have a harmful effect on ischaemic stroke; however, the underlying mechanism remains to be elucidated. Although Dl-3-n-butylphthalide is a multitarget agent for antiischaemic stroke, its neuroprotective role in brain ischaemia accompanied by brain venous disturbance remains unclear. In this study, we induced cerebral venous disturbance by the occlusion of bilateral external jugular veins (EJVs) to explore the potential mechanism of the adverse effects of cerebrovenous disorders in cerebral infarction and explore the protective effect of Dl-3-n-butylphthalide on cerebral infarction accompanied through cerebral venous disturbance.

Methods

Cerebral venous disturbance was induced in Sprague-Dawley rats through the permanent occlusion of bilateral EJVs, and cerebral ischaemic stroke was induced through the permanent occlusion of the right cortical branches of the middle cerebral artery. 2,3,5-triphenyltetrazolium chloride staining, MRI, Evans blue extravasation and behavioural test were performed to evaluate infarction volume, cerebral blood flow (CBF), blood–brain barrier (BBB) integrity and neurological function. Immunofluorescence staining and western blot analysis were performed to detect loss of neuron, endothelial cells, pericytes and tight junctions.

Results

Bilateral EJVs occlusion did not cause cerebral infarction; however, it increased the infarction volume compared with the simple middle cerebral artery occlusion (MCAO) group, accompanied by severe neuron loss, worse neurological function, lower CBF, increased EJVs pressure, exacerbated Evans blue extravasation and brain oedema, as well as attenuated angiogenesis. Dl-3-n-butylphthalide displayed a neuroprotective effect in rats with MCAO accompanied by EJVs occlusion by reducing neuron loss, accelerating CBF restoration, promoting angiogenesis and relieving BBB damage.

Conclusion

Bilateral EJVs occlusion did not significantly affect normal rats but aggravated brain damage in the case of ischaemic stroke. Dl-3-n-butylphthalide treatment plays a neuroprotective role in rats with MCAO accompanied by EJVs occlusion, mainly due to the promotion of CBF restoration and BBB protection.

Cerebral blood flow, cerebrovascular reactivity and their influence on ventilatory sensitivity

NEW FINDINGS

What is the topic of this review? Cerebrovascular reactivity to CO₂ , which is a principal factor in determining ventilatory responses to CO₂ through the role reactivity plays in determining cerebral extra- and intracellular pH. What advances does it highlight? Recent animal evidence suggests central chemoreceptor vasculature may demonstrate regionally heterogeneous cerebrovascular reactivity to CO₂ , potentially as a protective mechanism against excessive CO₂ washout from the central chemoreceptors, thereby allowing ventilation to reflect the systemic acid-base balance needs (respiratory changes in P aC O 2 ) rather than solely the cerebral needs. Ventilation per se does not influence cerebrovascular reactivity independent of changes in P aC O 2 .

ABSTRACT

Alveolar ventilation and cerebral blood flow are both predominantly regulated by arterial blood gases, especially arterial P C O 2 , and so are intricately entwined. In this review, the fundamental mechanisms underlying cerebrovascular reactivity and central chemoreceptor control of breathing are covered. We discuss the interaction of cerebral blood flow and its reactivity with the control of ventilation and ventilatory responsiveness to changes in P C O 2 , as well as the lack of influence of ventilation itself on cerebrovascular reactivity. We briefly summarize the effects of arterial hypoxaemia on the relationship between ventilatory and cerebrovascular response to both P C O 2 and P O 2 . We then highlight key methodological considerations regarding the interaction of reactivity and ventilatory sensitivity, including the following: regional heterogeneity of cerebrovascular reactivity; a pharmacological approach for the reduction of cerebral blood flow; reactivity assessment techniques; the influence of mean arterial blood pressure; and sex-related differences. Finally, we discuss ventilatory and cerebrovascular control in the context of high altitude and congestive heart failure. Future research directions and pertinent questions of interest are highlighted throughout.

Effect of positive end-expiratory pressure and positioning on jugular vein expansion in emergency department patients

OBJECTIVE

Guidelines recommend Trendelenburg position for central venous cannulation. Critically ill patients in the emergency department often do not tolerate this positioning or have contraindications. Thirty-degree dorsal elevated position with positive end-expiratory pressure by noninvasive ventilation could pose an alternative. This is the first trial to investigate the feasibility of alternative for central venous cannulation in critically ill emergency department patients.

METHODS

Ninety-one critically ill patients in the emergency department of Jena University Hospital were examined between August 2014 and May 2015. The cross-sectional area of the right internal jugular vein was measured in 3 different positions: 30° elevation, supine, and Trendelenburg position. Measurements were repeated with a continuous application of noninvasive ventilation.

RESULTS

Cross-sectional area of the right internal jugular vein in Trendelenburg position was largest (0.99 ± 0.66 cm) compared to supine (0.57 ± 0.58 cm) and 30° elevated position (0.25 ± 0.41 cm). In 30° elevated positioning, application of positive end-expiratory pressure significantly enlarged cross-sectional area (0.62 ± 0.70 cm). Noninvasive ventilation was a well-tolerated procedure (98%). In 30° elevated positioning with positive end-expiratory pressure a safe puncture (cross-sectional area ≥ 0.4 cm) could be expected in 68.1% of cases.

CONCLUSION

Thirty-degree elevated positioning with positive end-expiratory pressure via noninvasive ventilation could be a safe and well-tolerated alternative for central venous cannulation, especially for critically ill patients in emergency department unable to remain in Trendelenburg position. This proof-of-concept trial enables further studies with actual central venous cannulation.

Posture-induced changes in the vessels of the head and neck: evaluation using conventional supine CT and upright CT

Since the venous system is affected by gravity, upright computed tomography (CT) in addition to conventional supine CT has great potential for evaluating postural changes in the venous system. We evaluated the morphological differences in the head and neck vessels by performing a contrast CT study in both the supine and the sitting positions. In this study, the 20 included participants (10 men and 10 women) were healthy adults aged 30 to 55 years. The cross-sectional area of the cervical vessels, craniocervical junction veins, and intracranial vessels were obtained quantitatively. Venous sinuses and venous plexuses that were difficult to measure were evaluated qualitatively. The average change in areas from a supine to an upright posture was - 77.87 ± 15.99% (P < 0.0001) in the right internal jugular vein (IJV), - 69.42 ± 23.15% (P < 0.0001) in the left IJV, - 61.52 ± 12.81% (P < 0.0001) in the right external jugular vein (EJV), and - 58.91 ± 17.37% (P < 0.0001) in the left EJV. In contrast, the change in the anterior condylar vein (ACV) from a supine to an upright posture was approximately + 144% (P < 0.005) on the right side and + 110% (P < 0.05) on the left side. In addition, according to the qualitative analysis, the posterior venous structures including the anterior condylar confluence (ACC) of the craniocervical junction became more prominent in an upright posture. Despite these changes, the intracranial vessels showed almost no change between postures. From a supine to an upright position, the IJVs and EJVs above the heart collapsed, and venous channels including the ACCs and ACVs opened, switching the main cerebral venous drainage from the IJVs to the vertebral venous system. Upright head CT angiography can be useful for investigating physiological and pathophysiological hemodynamics of the venous system accompanying postural changes.

Jugular Venous Reflux Can Mimic Posterior Fossa Dural Arteriovenous Fistulas on MRI-MRA

Dural arteriovenous fistulas (DAVFs) are high-flow acquired shunts that can carry high risk of intracranial hemorrhage. Because DAVFs can often be managed by endovascular means, early and accurate diagnosis can markedly improve patient morbidity. Time-of-flight and arterial spin-labeling MRA have increased the diagnostic utility of MRI for DAVF by showing hemodynamic rather than anatomic evidence of shunting. The purpose of this article is to describe the cases of seven patients who had co-localization of arterial spin-labeling signal intensity and time-of-flight flow-related enhancement in the left skull base, resulting in a misdiagnosis of DAVF and a recommendation for catheter angiography by the interpreting radiologist. Benign jugular venous reflux is identified as a common mechanism in each case, and the physiology behind this imaging pitfall is described. An algorithmic diagnostic approach to differentiating physiologic venous reflux from true posterior skull base DAVFs is presented.

The developing brain by trimester

Transient anatomical entities play a role in the maturation of brain regions and early functional fetal networks. At the postmenstrual age of 7 weeks, major subdivisions of the brain are visible. At the end of the embryonic period, the cortical plate covers the neopallium. The choroid plexus develops in concert with it, and the dorsal thalamus covers about half the diencephalic third ventricle surface. In addition to the fourth ventricle neuroepithelium the rhombic lips are an active neuroepithelial production site. Early reciprocal connections between the thalamus and cortex are present. The corticospinal tract has reached the pyramidal decussation, and the arteries forming the mature circle of Willis are seen. Moreover, the superior sagittal sinus has formed, and at the rostral neuropore the massa commissuralis is growing. At the viable preterm age of around 24 weeks PMA, white matter tracts are in full development. Asymmetric progenitor division permits production of neurons, subventricular zone precursors, and glial cells. Myelin is present in the ventral spinal quadrant, cuneate fascicle, and spinal motor fibers. The neopallial mantle has been separated into transient layers (stratified transitional fields) between the neuroepithelium and the cortical plate. The subplate plays an important role in organizing the structuring of the cortical plate. Commissural tracts have shaped the corpus callosum, early primary gyri are present, and opercularization has started caudally, forming the lateral fissure. Thalamic and striatal nuclei have formed, although GABAergic neurons continue to migrate into the thalamus from the corpus gangliothalamicum. Near-term PMA cerebral sublobulation is active. Between 24 and 32 weeks, primary sulci develop. Myelin is present in the superior cerebellar peduncle, rubrospinal tract, and inferior olive. Germinal matrix disappears from the telencephalon, except for the GABAergic frontal cortical subventricular neuroepithelium.

Effect of lumbar elevation on dilatation of the central veins in normal subjects

BACKGROUND

Increasing the size of the central veins is required to increase the success rate of central line placement and decrease complication risk. Right-sided approach for the central veins, Valsalva maneuver, and Trendelenburg position have been recommended, but these may not be available for some cases. This study aimed to determine a more convenient patient position that can result in the largest central vein diameter.

METHODS

Recruited subjects were placed in 60° and 30° upper body elevation, supine position, and 30° and 60° lower body elevation, and lumbar elevation (LE) was consecutively performed, with one position maintained for 10 min. Diameters of the subclavian vein (SCV) and internal jugular vein (IJV) were measured using high-resolution two-dimensional ultrasonography at each position.

RESULTS

The most suitable position on the ordinary bed for increasing central vein diameter was LE. The maximum and minimum SCV and IJV diameters in LE were significantly larger than those in the supine position (SCV: coefficients -0.633 and -0.863, p = 0.08 and 0.011, respectively; IJV: coefficients -1.09 and -1.15, p < 0.001 and = 0.001, respectively). Leg elevation for 10 min failed to dilate the central vein diameter.

CONCLUSION

The LE without leg elevation produced a greater and more significant increase in central vein diameter than the supine position and may be useful for central line placement.

Reasons of unsuccessful implantation of short-term hemodialysis catheters in jugular veins using real-time ultrasound

PURPOSE

Real-time ultrasound is indicated for hemodialysis catheters' insertion in internal jugular veins. We evaluated unsuccessful implantation of short-term hemodialysis catheters in internal jugular veins using real-time ultrasound between patients with and without previous short-term catheters.

METHODS

Observational open-label study of unsuccessful implantation of short-term hemodialysis catheters in internal jugular veins using real-time ultrasound from July 2013 to August 2014.

RESULTS

A total of 185 procedures were compared in 122 individuals; 120 (64.86%) had previously used short-term catheters. There were 5 (8%) unsuccessful implantation among 62 catheterizations without previous short-term catheter and 41 (33.6%) among 122 with previous short-term catheter (p = 0.001 Pearson's chi-squared, odds ratio = 5.77, 95% confidence interval = 2.15-15.50, p = 0.001). Non-progressing guidewire occurred in 2 (3.2%) of 62 patients without previous short-term catheter and in 18 (14.8%) of 122 with previous short-term catheter (p = 0.018 Pearson's chi-squared, odds ratio = 5.19, 95% confidence interval = 1.16-23.15, p = 0.031). No difference was observed between size of the veins with or without non-progressing guidewire. All 11 cases of venous thrombosis occurred in patients who had previous short-term catheter removed due to infection.

CONCLUSION

Previous use of short-term catheter is pivotal in the occurrence of unsuccessful implantation of short-term catheter in internal jugular veins using real-time ultrasound.

Radiologic features of vascular pulsatile tinnitus - suggestion of optimal diagnostic image workup modalities

OBJECTIVES

The aim of this study was to determine the optimal diagnostic workup modalities for vascular pulsatile tinnitus through analysis of clinical and radiologic findings.

MATERIALS AND METHODS

A total of 49 patients diagnosed with vascular pulsatile tinnitus along with their medical records and radiologic findings were thoroughly reviewed.

RESULTS

Of these patients, 84% had venous lesions. The jugular bulb variants (67%) were the most common venous lesions followed by sigmoid sinus variants (12%). About 88% (43/49) of these lesions were detected with computed tomography of the temporal bone (TBCT) alone and the lesions were either venous or intratemporal artery in origin. Simple manual neck compression test was 93% sensitive in predicting venous lesions. A high suspicion for venous lesion coupled with manual neck compression test and selection of the optimal imaging technique are useful for the proper evaluation of vascular pulsatile tinnitus at the initial visit.

CONCLUSION

Our stepwise strategy may increase the cost-effectiveness of the chosen imaging workup by reducing redundancy of multiple and simultaneous radiologic tests in patients with vascular pulsatile tinnitus.

Use of Phase-Contrast MRA to Assess Intracranial Venous Sinus Resistance to Drainage in Healthy Individuals

BACKGROUND AND PURPOSE

Resistance to blood flow in the cerebral drainage system may affect cerebral hemodynamics. The objective of the present study was to use phase-contrast MRA to quantify resistance to drainage of blood across branches of the venous sinus tree and to determine whether the resistance to drainage values correlated with internal jugular vein outflows.

MATERIALS AND METHODS

We performed whole-head phase-contrast MRA and 2D phase-contrast MR imaging in 31 healthy volunteers. Vascular segmentation was applied to the angiograms, and the internal jugular vein velocities were quantified from the flow images. Resistance to drainage across branches of the venous sinus tree was calculated from the segmented angiograms, by using the Poiseuille equation for laminar flow. Correlations between the values of resistance to drainage and internal jugular vein outflow measurements were assessed by using the Spearman ρ.

RESULTS

The overall mean resistance to drainage of the venous sinus tree was 24 ± 7 Pa s/cm³. The mean resistance to drainage of the right side of the venous sinus tree was 42% lower than that of the left side (P < .001). There were negative correlations between the values of resistance to drainage and internal jugular vein outflows on both the left side of the venous sinus tree (R = -0.551, P = .002) and the right side (R = -0.662, P < .001).

CONCLUSIONS

Phase-contrast MRA is a noninvasive means of calculating the resistance to drainage of blood across the venous sinus tree. Our approach for resistance to drainage quantification may be of value in understanding alterations in the cerebral venous sinus drainage system.

[Application of ultrasonography in central venous catheterization; access sites and procedure techniques]

Central venous catheterization is commonly performed in clinical practice. Traditional procedural technique is based on anatomical landmarks, but is associated with a high risk of failure and complications. To decrease their incidence European and American societies recommend application of ultrasonography. Preliminary ultrasonographic examination allows for assessment of local anatomical relations as well as vessel morphology (diameter, patency), while real-time ultrasonography increases chances of successful needle insertion. This paper presents the most common venous access sites and procedure techniques.

Extracranial Venous abnormalities: A true pathological finding in patients with multiple sclerosis or an anatomical variant?

OBJECTIVE

To evaluate the extracranial venous anatomy with contrast-enhanced MR venogram (CE-MRV) in patients without multiple sclerosis (MS), and assess the prevalence of various venous anomalies such as asymmetry and stenosis in this population.

MATERIALS AND METHODS

We prospectively recruited 100 patients without MS, aged 18-60 years, referred for contrast-enhanced MRI. They underwent additional CE-MRV from skull base to mediastinum on a 3T scanner. Exclusion criteria included prior neck radiation, neck surgery, neck/mediastinal masses or significant cardiac or pulmonary disease. Two neuroradiologists independently evaluated the studies to document asymmetry and stenosis in the jugular veins and prominence of collateral veins.

RESULTS

Asymmetry of internal jugular veins (IJVs) was found in 75 % of subjects. Both observers found stenosis in the IJVs with fair agreement. Most stenoses were located in the upper IJV segments. Asymmetrical vertebral veins and prominence of extracranial collateral veins, in particular the external jugular veins, was not uncommon.

CONCLUSION

It is common to have stenoses and asymmetry of the IJVs as well as prominence of the collateral veins of the neck in patients without MS. These findings are in contrast to prior reports suggesting collateral venous drainage is rare except in MS patients.

KEY POINTS

• The venous anatomy of the neck in patients without MS demonstrates multiple variants • Asymmetry and stenoses of the internal jugular veins are common • Collateral neck veins are not uncommon in patients without MS • These findings do not support the theory of chronic cerebrospinal venous insufficiency • MR venography is a useful imaging modality for assessing venous anatomy.

Comparison of the diameter, cross-sectional area, and position of the left and right internal jugular vein and carotid artery in adults using ultrasound

STUDY OBJECTIVE

Central venous access is indicated for transduction of central venous pressure and the administration of inotropes in the perioperative period. The right internal jugular vein (RIJV) is cannulated preferentially over the left internal jugular vein (LIJV). Cannulation of the LIJV is associated with a higher complication rate and a perceived increased level of difficulty when compared with cannulation of the RIJV. Possible explanations for the higher complication rate include a smaller diameter and more anterior position relative to the corresponding carotid artery (CA) of the LIJV compared with the RIJV. In this study, the RIJV and LIJV were examined in mechanically ventilated patients to determine the validity of these possible explanations.

DESIGN

A prospective, nonrandomized cohort study.

SETTING

The operating room of a major teaching hospital.

PATIENTS

One hundred fifty-one patients scheduled for elective heart surgery.

INTERVENTION

Ultrasound examination of the RIJV and LIJV at the level of the cricoid cartilage with a 12-MHz linear transducer in 151 anesthetized, mechanically ventilated patients in the Trendelenburg position.

MEASUREMENTS AND RESULTS

In 72% of patients, the RIJV was dominant over the LIJV. The diameter and cross-sectional area of the RIJV was larger than the LIJV (P < .001). An anterior position of the LIJV in relation to the left CA was detected more often when compared with the RIJV and right CA (15.1% vs 5.4%, P = .01).

CONCLUSION

This study confirms the smaller diameter and increased frequency of anterior positioning relative to the corresponding CA of the LIJV when compared with the RIJV. This validates them as possible explanations for the higher complication rate of LIJV cannulation compared with RIJV cannulation.

Assessment of Internal Jugular Vein Size in Healthy Subjects with Magnetic Resonance and Semiautomatic Processing

Background and Objectives. The hypothesized link between extracranial venous abnormalities and some neurological disorders awoke interest in the investigation of the internal jugular veins (IJVs). However, different IJV cross-sectional area (CSA) values are currently reported in literature. In this study, we introduced a semiautomatic method to measure and normalize the CSA and the degree of circularity (Circ) of IJVs along their whole length. Methods. Thirty-six healthy subjects (31.22 ± 9.29 years) were recruited and the 2D time-of-flight magnetic resonance venography was acquired with a 1.5 T Siemens scanner. The IJV were segmented on an axial slice, the contours were propagated in 3D. Then, IJV CSA and Circ were computed between the first and the seventh cervical levels (C1-C7) and normalized among subjects. Inter- and intrarater repeatability were assessed. Results. IJV CSA and Circ were significantly different among cervical levels (p < 0.001). A trend for side difference was observed for CSA (larger right IJV, p = 0.06), but not for Circ (p = 0.5). Excellent inter- and intrarater repeatability was obtained for all the measures. Conclusion. This study proposed a reliable semiautomatic method able to measure the IJV area and shape along C1-C7, and suitable for defining the normality thresholds for future clinical studies.

[Bleeding during central venous catheterization : Cannot intubate, cannot ventilate due to massive cervical hematoma]

Central venous catheterization is an invasive procedure which can be associated with severe complications. These include in particular unsuccessful arterial puncture and vascular injuries, which in addition to loss of blood can lead to massive soft tissue swelling. A 63-year-old female patient developed massive cervical bleeding during ultrasound-guided internal jugular vein puncture and the rapidly enlarging hematoma led to compromisation of the airway. A cannot intubate, cannot ventilate situation developed and the subsequent hypoxia led to cardiac arrest that was only resolved after emergency surgical tracheotomy during cardiopulmonary resuscitation.

Achieving optimal clinical outcomes in ultrasound-guided central venous catheterizations of the internal jugular vein after a simulation-based training program for novice learners

INTRODUCTION

The aim of this study was to determine the number of ultrasound-guided (USG) central venous catheterization (CVC) of the internal jugular vein (IJV) residents had to perform, after a simulation-based training program, to achieve optimal clinical outcomes.

METHODS

We conducted a single-center, prospective, observational study in the medical intensive care unit of a university-affiliated teaching hospital. Residents participated in a formal training program, consisting of a simulation-based workshop and 5 supervised USG CVC insertions on patients. Subsequent USG CVC of the IJV performed by residents during their rotation were assessed. Data on the overall success (OS), first pass success (FP) and mechanical complication (MC) rates were serially collected over 2 years, spanning 4 cohorts of residents.

RESULTS

Thirty-two residents performed a total of 337 USG CVC of the IJV. Residents had previously performed an average of 9 CVC via the landmark technique. None had performed USG CVC before. Results showed that residents improved in their OS, FP, and MC rates as they performed more USG CVC. Residents needed to perform 7 USG CVCs to achieve optimal clinical outcomes of high OS and FP as well as low MC rates. There was a significant improvement in OS, FP, and MC rates for the eighth and subsequent USG CVCs compared with the first 7 USG CVCs (82% vs. 99% [P < 0.001], 70% vs. 92% [P < 0.001] and 11% vs. 0%, respectively).

CONCLUSIONS

After a formal training program consisting of a simulation-based workshop and 5 supervised USG CVCs on critically ill adults, residents were able to achieve optimal clinical outcomes after performing 7 procedures.

Internal jugular veins must be measured before catheterization

STUDY OBJECTIVE

The study objective is to determine the cross-sectional area (CSA) of the right and left internal jugular vein (IJV) in supine position in healthy subjects.

DESIGN

This is a prospective, nonrandomized study.

SETTING

The setting is a university hospital.

PATIENTS

The patients are 185 consenting healthy subjects.

INTERVENTIONS

B-mode ultrasonography examinations of the right and left IJV were performed with the use of a linear 14-MHz transducer at the level of the cricoid cartilage. The CSA of the examined vessels was measured in a supine position.

MEASUREMENTS AND MAIN RESULTS

The CSA on both sides differed by up to 850%. There were no statistically significant differences between CSA of IJVs in men and women. The CSA of the IJV on the right side was significantly greater than on the left side. The right IJV was more often classified as the "dominant" vessel (CSA being more than twice as large as the opposite side). A "small" vessel (CSA ≤ 0.4 cm(2)) was found in 54 cases (14.6%). In 9 subjects (4.9%), they were detected bilaterally.

CONCLUSION

The CSA of IJVs varies widely. Although the CSA was found to be often greater on the right than on the left side, a "small" vessel may occur on both sides.

Evaluation of hemodynamic properties of cerebral venous drainage in patients with multiple sclerosis: a case-control study

Background

The purpose of this study was to compare patients with multiple sclerosis and healthy control subjects as regards hemodynamics of cerebral venous drainage.

Material/Methods

Between December 2012 and May 2013, 44 consecutive patients with multiple sclerosis and 44 age- and sex-matched healthy subjects underwent the B-mode, color Doppler, and duplex Doppler evaluations of the internal jugular vein (IJV) and vertebral vein. The following four parameters were investigated: IJV stenosis, reversal of postural control of the cerebral venous outflow pathways, absence of detectable blood flow in the IJVs and/or vertebral veins, and reflux in the IJVs and/or vertebral veins in the sitting or supine position.

Results

In the study group, IJV stenosis, postural control reversal of the cerebral venous outflow pathways, and absence of flow in the IJVs and/or vertebral veins were found in 3 (6.8%), 2 (4.5%), and 3 (6.8%) patients, respectively. In the control group, IJV stenosis (P=0.12), postural control reversal of the cerebral venous outflow pathways (P=0.50), and absence of flow (P=0.12) were not detected. Abnormal reflux was found neither in multiple sclerosis patients nor in healthy subjects.

Conclusions

No significant difference in the cerebral venous drainage through the IJV or vertebral vein was found between patients with multiple sclerosis and healthy subjects within any of the investigated ultrasonographic parameters.

Endovascular treatment of chronic cerebro spinal venous insufficiency in patients with multiple sclerosis modifies circulating markers of endothelial dysfunction and coagulation activation: a prospective study

We performed a monocentric observational prospective study to evaluate coagulation activation and endothelial dysfunction parameters in patients with multiple sclerosis undergoing endovascular treatment for cerebro-spinal-venous insufficiency. Between February 2011 and July 2012, 144 endovascular procedures in 110 patients with multiple sclerosis and chronical cerebro-spinal venous insufficiency were performed and they were prospectively analyzed. Each patient was included in the study according to previously published criteria, assessed by the investigators before enrollment. Endothelial dysfunction and coagulation activation parameters were determined before the procedure and during follow-up at 1, 3, 6, 9, 12, 15 and 18 months after treatment, respectively. After the endovascular procedure, patients were treated with standard therapies, with the addition of mesoglycan. Fifty-five percent of patients experienced a favorable outcome of multiple sclerosis within 1 month after treatment, 25% regressed in the following 3 months, 24.9% did not experience any benefit. In only 0.1% patients, acute recurrence was observed and it was treated with high-dose immunosuppressive therapy. No major complications were observed. Coagulation activation and endothelial dysfunction parameters were shown to be reduced at 1 month and stable up to 12-month follow-up, and they were furthermore associated with a good clinical outcome. Endovascular procedures performed by a qualified staff are well tolerated; they can be associated with other currently adopted treatments. Correlations between inflammation, coagulation activation and neurodegenerative disorders are here supported by the observed variations in plasma levels of markers of coagulation activation and endothelial dysfunction.

The fluctuating natural course of CCSVI in MS patients and controls, a prospective follow-up

Objectives

A new treatable venous disorder, chronic cerebrospinal venous insufficiency (CCSVI), has been proposed in patients with multiple sclerosis. The natural course of CCSVI has not been examined yet. This is crucial given the fact that surgical procedures are increasingly offered to MS patients to treat venous stenosis.

Methods

To document the natural course of venous haemodynamics we performed extra- and transcranial echo colour Doppler (ECD) in 52 multiple sclerosis patients and 28 healthy controls (HC) and re-examined this group after a median period of 16 weeks. The reexamination was done being blinded to the initial findings and the patients did not undergo any intervention.

Results

The ECD examination at baseline showed CCSVI in 5 (9.6%) of the 52 multiple sclerosis patients and 0 HC (P = 0.26). At follow-up the diagnosis CCSVI could not be reconfirmed in 3 out of 5 patients at follow-up, while 2 new CCSVI-positive multiple sclerosis patients were detected.

Conclusions

ECD examination shows a fluctuating natural course of the extracranial venous haemodynamics, which makes determination of CCSVI by ECD examination unreliable.

Doppler ultrasound examination of multiple sclerosis patients and control participants: inter-observer agreement and association with disease

OBJECTIVE

Chronic cerebrospinal venous insufficiency (CCSVI) has been proposed as a major risk factor for multiple sclerosis (MS). The aim of this study was to assess inter-observer agreement between two ultrasound examiners and to compare findings in MS patients and control participants.

METHODS

A prospective, blinded, controlled study of MS patients diagnosed within 2 years (MS ≤ 2, n = 39), patients diagnosed more than 10 years ago (MS > 10, n = 43) and age- and sex-matched control participants (n = 40). Ultrasound examinations were performed by two independent examiners. CCSVI criteria 1, 3, 4 and 5 as proposed by Zamboni were explored: (1) reflux in the internal jugular (IJV) and vertebral veins (VV), (3) IJV cross-sectional area (CSA) ≤0.3 cm(2), (4) absence of flow in IJV and VV, and (5) reverted postural control of venous outflow.

RESULTS

Criteria 1, 4 and 5 were met in less than 10% of the MS patients and control participants as studied by both examiners. The level of inter-observer agreement was poor for all parameters except assessment of the CSA of IJV at the thyroid level. Findings meeting CCSVI criterion 3 (CSA ≤ 0.3 cm(2)) were observed in 18/40 (45%) of the control participants, in 24/37 (65%) of MS ≤ 2 patients (p = 0.09 vs. control participants) and in 30/43 (70%) of the MS > 10 patients (p = 0.022 vs. control participants).

CONCLUSIONS

The feasibility of the CCSVI criteria for common use is questionable because of low inter-observer agreement. Small-calibre IJVs meeting the CCSVI criterion 3 appear common in both Finnish control participants and MS patients, but the clinical significance of this finding is questionable.

Increased deep gray matter iron is present in clinically isolated syndromes

OBJECTIVE

Abnormal iron accumulation in MS has been known for decades, however it remains to be established whether iron reflects a cause or epiphenomenon of pathology. The objective of the present study is to determine if iron is increased in the brains of patients with clinically isolated syndromes (CIS) suggestive of early MS.

METHODS

Twenty-two patients with a CIS and 16 age- and sex-matched controls underwent 3T MRI studies. Differences in R2*, a metric of iron concentration, were assessed for all voxels throughout the brain. Similar clusters of significant differences were grouped, wherein mean R2* was regressed against a number of parameters, including extended disability status scale (EDSS), age, disease duration, and internal jugular vein (IJV) cross-sectional area (CSA), as measured from magnetic resonance time-of-flight venograms.

RESULTS

Patients had significantly increased R2* in globus pallidus, thalamus, right pulvinar, and cortical areas. Thalamic R2* correlated positively with EDSS. Decreased white matter R2* was detected at various positions in the patient group average. No correlations were found between any changes in R2* and IJV CSA.

INTERPRETATION

Iron is increased in CIS in deep gray matter, suggesting this iron accumulation, well-known in definite MS, occurs early in the disease course. Increases in thalamic iron are associated with worsened clinical status. Decreased white matter R2* may be interpreted as diffuse damage to normal appearing white matter, not often reported in CIS. Observations do not support a role for venous abnormalities in either iron accumulation or white matter damage.

Small internal jugular veins with restricted outflow are associated with severe multiple sclerosis: a sonographer-blinded, case-control ultrasound study

BACKGROUND

Recent evidence has indicated an association between chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis. Small internal jugular veins (IJVs) (with a cross-sectional area of less than 0.4 cm²) have been previously described as difficult to catheterize, and their presence may potentially affect cerebrospinal venous drainage. In this blinded extracranial color-Doppler study we had two principal aims: first, to assess prevalence of CCSVI among Serbian MS patients compared to healthy controls; and second, to assess prevalence of small IJVs (with a CSA ≤ 0.4 cm²) among MS patients and controls.

METHODS

The sixty seven unrelated patients with clinical isolated syndrome (CIS), relapsing-remitting (RR), secondary progressive (SP) and primary progressive (PP) multiple sclerosis and 21 healthy controls were examined by high-resolution color-Doppler.

RESULTS

The ultrasonographic criteria of CCSVI (according to Zamboni) were positive in 11.9% of the patients and in none of the control subjects. The CCSVI-positive patients had significantly longer disease durations and were significantly more disabled (measured by their Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Severity Score (MSSS) scores), but after adjustment for gender and disease duration, CCSVI was not an independent risk factor for multiple sclerosis severity. The small IJVs were found in 28.4% of the patients and 28.6% of the controls. The patients with small IJVs were associated with decreased venous outflow from the brain and presented with longer disease durations and significantly higher EDSS and MSSS scores compared to patients without small IJVs. A multivariate logistic regression analysis adjusted for gender and disease duration showed that small IJV is an independent factor associated with multiple sclerosis severity (EDSS ≥6) (adjusted OR = 8.9, 95% CI: 1.8-45.6, p = 0.007). Among patients with small IJVs the 36.84% were also CCSVI positive.

CONCLUSIONS

Both, CCSVI and small IJVs seem to influence or follow MS severity, but only small IJVs turned out to be an independent factor in this study. Thus, small IJVs with restricted outflow, which might be aspects of CCSVI different from the criteria originally described by Zamboni, emerge as a cofactor in the multifactorial pathophysiology of multiple sclerosis.

What went wrong? The flawed concept of cerebrospinal venous insufficiency

In 2006, Zamboni reintroduced the concept that chronic impaired venous outflow of the central nervous system is associated with multiple sclerosis (MS), coining the term of chronic cerebrospinal venous insufficiency ('CCSVI'). The diagnosis of 'CCSVI' is based on sonographic criteria, which he found exclusively fulfilled in MS. The concept proposes that chronic venous outflow failure is associated with venous reflux and congestion and leads to iron deposition, thereby inducing neuroinflammation and degeneration. The revival of this concept has generated major interest in media and patient groups, mainly driven by the hope that endovascular treatment of 'CCSVI' could alleviate MS. Many investigators tried to replicate Zamboni's results with duplex sonography, magnetic resonance imaging, and catheter angiography. The data obtained here do generally not support the 'CCSVI' concept. Moreover, there are no methodologically adequate studies to prove or disprove beneficial effects of endovascular treatment in MS. This review not only gives a comprehensive overview of the methodological flaws and pathophysiologic implausibility of the 'CCSVI' concept, but also summarizes the multimodality diagnostic validation studies and open-label trials of endovascular treatment. In our view, there is currently no basis to diagnose or treat 'CCSVI' in the care of MS patients, outside of the setting of scientific research.

Intracranial nonjugular venous pathways: a possible compensatory drainage mechanism

BACKGROUND AND PURPOSE

The IJVs are considered to be the main pathway draining the intracranial venous system. There is increasing evidence for the existence of alternative venous pathways. Studies using extracranial sonography techniques have demonstrated a nonjugular venous system. In the current study, we used MR images to investigate the NJV drainage system and its components (vertebral plexus, pterygopalatine plexus). The exact visualization and measurement of the intracranial NJVs could be of diagnostic importance and may have clinical importance.

MATERIALS AND METHODS

A total of 64 participants with no history of neurologic disease were included in the study. All participants underwent scanning with a 2D time-of-flight, multisection sequence in the supine position. Image processing software was developed to identify and quantify the size of the IJVs and NJVs in the plane of the internal JF. For evaluation of software accuracy, all images were reviewed by a neuroradiologist experienced in neurovascular imaging preprocessing and postprocessing.

RESULTS

The CSA of the NJVs correlated inversely with the CSA of the IJVs (r(2) = 0.25; P < .0001). An inverse correlation was also significant when comparing IJV with NJV components (vertebral plexus: r(2) = 0.19; P = .0004; pterygopalatine plexus: r(2) = 0.11; P = .0069). Furthermore, only NJV cumulative CSA correlated inversely with participant age (r(2) = 0.2; P = .0002).

CONCLUSIONS

Our study indicates that the NJVs might serve as a compensatory drainage mechanism in the intracranial compartment. This mechanism appears less significant as the age of the patient progresses.

Mystery of chronic cerebrospinal venous insufficiency: identical venographic and ultrasound findings in patients with MS and controls

BACKGROUND AND PURPOSE

Stenosis of the internal jugular, azygos, and other veins detected by using intracranial and neck Doppler and B-mode sonography and confirmed by venography has been reported in MS with a high degree of sensitivity. This article reports the results of sonographic findings in patients with MS and controls, looking for evidence of the controversial entity chronic cerebrospinal venous insufficiency. Furthermore, the venographic appearance in controls is documented.

MATERIALS AND METHODS

Thirty consecutive patients with definite MS and 10 controls had TCD and high-resolution Doppler sonography of the neck vessels by using the published sonography criteria of Zamboni et al. Those with 2 positive findings consented to undergo contrast digital subtraction venography for delineation of possible venous stenosis. Nine consecutive patients undergoing digital subtraction venography for petrosal venous sampling or parathormone sampling had images of their internal jugular veins obtained as part of their procedure, and they were assessed for stenosis.

RESULTS

No patient with MS or control had 2 positive sonographic findings; therefore, none were subjected to venography. Of the 9 controls undergoing venography for other reasons, 6 had bilateral IJV narrowing of ≥50%, and 2 others had unilateral narrowing.

CONCLUSIONS

No difference was detected between patients with MS and controls by using the objective sonographic criteria of Zamboni et al. Furthermore, normal physiologic narrowing is found very commonly in the internal jugular veins in healthy individuals. Nonblinded subjective sonographic assessment of the IJV may erroneously lead to venography, the findings of which may be misinterpreted due to the lack of widespread knowledge about the appearance of these veins in healthy individuals.

Chronic cerebrospinal venous insufficiency is not more prevalent in patients with mild multiple sclerosis: a sonographer-blinded, case-control ultrasound study

OBJECTIVES

We designed a prospective case-control study of patients with clinically isolated syndrome (CIS) and Relapsing-Remitting Multiple Sclerosis (RRMS) with an Expanded Disability Status Score (EDSS) of ≤2, compared with age-and-sex-matched healthy controls, to test the hypothesis that chronic cerebrospinal venous insufficiency (CCSVI) is more prevalent in patients with CIS or mild MS.

METHODS

All subjects were examined using a Siemens Antares duplex ultrasound machine. The internal jugular, vertebral and intracranial veins were studied in subjects in both supine and sitting postures. The sonographer was blind to the subject's clinical status. Measures included the criteria proposed by Zamboni and volume flow. Presence of CCSVI was defined as ≥2 Zamboni criteria.

RESULTS

Seventy patient-control pairs were recruited, with 11 males and 59 females in each group. Only one subject, a control, satisfied the Zamboni definition of CCSVI; however, 19 patients and 13 controls had abnormalities as defined by Zamboni, the difference largely caused by a higher prevalence in patients of internal jugular vein (IJV) stenosis, defined as a cross-sectional area ≤0.3cm(2). This difference disappeared with a more rigorous stenosis definition. Further analysis revealed there was IJV valve variation in seven patients and one control.

CONCLUSIONS

Our findings indicate that CCSVI, as defined by the Zamboni ultrasound criteria, is not present in CIS and mild RRMS (EDSS ≤2), providing further evidence that CCSVI does not have a causal role in MS; however, we found an apparent increase in IJV variation in patients with CIS or mild MS that would warrant further investigation.

CCSVI and MS: a statement from the European Society of neurosonology and cerebral hemodynamics

To systematically review the ultrasonographic criteria proposed for the diagnosis of chronic cerebrospinal venous insufficiency (CCSVI). The authors analyzed the five ultrasonographic criteria, four extracranial and one intracranial, suggested for the diagnosis of CCSVI in multiple sclerosis (MS), together with the references from which these criteria were derived and the main studies that explored the physiology of cerebrospinal drainage. The proposed CCSVI criteria are questionable due to both methodological and technical errors: criteria 1 and 3 are based on a scientifically incorrect application of data obtained in a different setting; criteria 2 and 4 have never been validated before; criterion 2 is technically incorrect; criteria 3 and 5 are susceptible to so many external factors that it is difficult to state whether the data collected are pathological or a variation from the normal. It is also unclear how it was decided that two or more of these five ultrasound criteria may be used to diagnose CCSVI, since no validation of these criteria was performed by different and independent observers nor were they blindly compared with a validated gold-standard investigation. The European Society of Neurosonology and Cerebral Hemodynamics (ESNCH) has considerable concerns regarding the accuracy of the proposed criteria for CCSVI in MS. Therefore, any potentially harmful interventional treatment such as transluminal angioplasty and/or stenting should be strongly discouraged.

CCSVI and MS: no meaning, no fact

A condition called "chronic cerebrospinal venous insufficiency" (CCSVI) has been postulated to play a role in the pathogenesis of multiple sclerosis (MS). This hypothesis implies that a complex pattern of extracranial venous stenosis determines a venous reflux into the brain of MS patients, followed by increased intravenous pressure, blood-brain barrier breakdown and iron deposition into the brain parenchyma, thus triggering a local inflammatory response. In this review, we critically analyze the scientific basis of CCSVI, the current literature on the relationship between CCSVI and MS, as well as the ultrasound methodology that has been claimed to provide evidence of impaired cerebral venous drainage. We show that no piece of the CCSVI theory has a solid supportive scientific evidence. The CCSVI appears to be a rather alien condition and its existence should be definitely questioned. Finally, no proven (i.e., based on strict scientific methodology and on the rules of evidence-based medicine) therapeutic effect of the "liberation" procedure (unblocking the extracranial venous obstruction using angioplasty) has been shown up to date.

Dimension and overlap of femoral and neck blood vessels in neonates

INTRODUCTION

Neonates frequently require access to their central blood vessels. However, limited data exist relating to the size and the anatomical relation of the femoral and neck vessels for neonates of different postmenstrual ages.

HYPOTHESIS

1) The size of central blood vessels increases with postmenstrual age of the neonate. 2). External rotation with abduction at the hip will decrease the degree of overlap between the femoral artery and vein. 3) The degree of overlap decreases with increasing postmenstrual age.

DESIGN

Prospective descriptive cohort study.

MEASUREMENTS AND MAIN RESULTS

Femoral and neck vessel sizes were assessed using ultrasound for three postmenstrual age groups: group A (26 ± 1 wks), group B (32 ± 1 wks), and group C (38 ± 1 wks). The degrees of overlap (major, >50% overlap; minor, ≤50% overlap; no overlap) between the femoral vessels were assessed at the level of the inguinal ligament and 1 cm below the inguinal ligament in a straight hip and in external rotation with abduction of the hip positions. A total of 52 nonconsecutive subjects (group A, seven; group B, 21; group C, 24) were studied. The mean blood vessel dimensions increased with increasing postmenstrual age. Correlation of blood vessel size to growth measurements was better in group A + group B compared to group C. Overlap between the femoral vein and the femoral artery across the neonatal age groups at the level of the inguinal ligament ranged from 57% to 79% and from 43% to 98% at 1 cm below the inguinal ligament. The degree of overlap did not decrease with positioning of the lower extremity in external rotation with abduction of the hip. In the neck blood vessels, the majority of observations showed either minor or major overlap of neck blood vessels in all three groups (group A, 79%; group B, 86%; group C, 90%).

CONCLUSIONS

Central blood vessel size increases with increasing postmenstrual age. Correlation of blood vessel size to anthropometric measurements was better in the premature neonates compared to term neonates. A high degree of overlap exists within the femoral and cervical blood vessels. In the femoral vessels, the degree of overlap did not decrease with external rotation with abduction of the hip at any postmenstrual age.

Extra- and Transcranial Echo Colour Doppler in the Diagnosis of Chronic Cerebrospinal Venous Insufficiency

A new venous disorder, chronic cerebrospinal venous insufficiency (CCSVI), has been proposed in patients with multiple sclerosis (MS). It is a vascular condition characterized by an impaired cerebrospinal venous drainage due to obstructions in the main extracranial cerebrovenous outflow routes (i.e. internal jugular veins [IJV] and/or azygos veins). In this review, the studies which assessed the prevalence of CCSVI in MS by echo colour Doppler (ECD) will be discussed. The technical aspects of determination of the five CCSVI criteria: (1) reflux in the IJV and/or vertebral veins in supine and upright position, (2) reflux in the deep cerebral veins, (3) high-resolution B-mode proximal IJV stenosis, (4) flow not Doppler detectable in IJVs and/or vertebral veins (VVs) and (5) reverted postural control of the main cerebrovenous outflow pathway are described in detail. We conclude that so far there are many studies with contradictory results, and as yet a strong scientific base to support the evidence for a causative relationship of CCSVI and MS is lacking. Recent studies call into question the validity of using ECD as a proper and reliable test for the diagnosis of CCSVI. One explanation for the variety in interpretation of the individual CCSVI criteria, with the wide-ranging percentages CCSVI, could be the different methods by using ECD to determine various criteria.

Is a neutral head position safer than 45-degree neck rotation during ultrasound-guided internal jugular vein cannulation? Results of a randomized controlled clinical trial

BACKGROUND

The optimal degree of neck rotation during internal jugular vein (IJV) cannulation remains undetermined because previous studies suggested using sonography, but without puncturing the vein. We assessed whether a neutral position (NP) of the head (0 degrees) during ultrasound-guided cannulation of the IJV was safer than rotating the neck to 45 degrees head turned. The effect of these 2 positions during ultrasound-guided cannulation on major complications was the primary outcome. Overall complications, venous access time, and perception of difficulty during the procedure were also evaluated.

METHODS

A prospective, randomized, controlled, nonblinded study was conducted in a tertiary neurosurgical hospital. Patients undergoing major elective neurosurgical procedures requiring a central venous line were randomly allocated to 2 groups; ultrasound-guided cannulation of the IJV was then performed using an out-of-plane orientation.

RESULTS

One thousand four hundred twenty-four patients were evaluated, but 92 were excluded; 670 were allocated to the head turned group and 662 to the NP group. Cannulation was 100% successful. Demographic data were similar in the 2 groups except for IJV positions. There were only 10 major complications: 6 in the 0-degree NP group and 4 in the 45-degree head turned group. The frequency of these complications was not different between the 2 groups. The overall complication rate was 13%, and was higher in women, in patients with ASA physical status ≥II, and in patients with a smaller diameter vein, or when the vein was located deeper and lateral or in the anterolateral position. An increased venous access time was associated with an increased rate of overall complications. The perception of difficulty performing the procedure with the head placed in the 2 positions was not statistically different in either group.

CONCLUSION

A head NP was as safe as a 45-degree neck rotation during ultrasound-guided IJV cannulation with regard to both major and minor complications, and venous access time was similar. Ultrasound guidance helps determine optimal head rotation for IJV cannulation.

Jugular vein hypoplasia can preclude extracorporeal membrane oxygenation cannulation in the neonate with congenital diaphragmatic hernia: potential identification of the neonate at risk by fetal magnetic resonance imaging

Magnetic resonance imaging (MRI) is used routinely in many fetal care centers for the evaluation of the fetus with congenital diaphragmatic hernia (CDH). Current MRI strategies focus on identifying the type of hernia and its contents, as well as calculating fetal lung volumes, in order to plan appropriately for neonatal support, including the use of extracorporeal membrane oxygenation (ECMO). Single-shot fast spin-echo T(2)-weighted sequences are fundamental, with additional sequences used variably as indicated. We report the case of a fetus with CDH in whom ECMO cannulation was attempted as a neonate but was unsuccessful because of variant anatomy of the internal jugular vein. A retrospective review of gradient echo sequences obtained through the fetal neck and chest showed the abnormality could have been anticipated. During multidisciplinary assessment of the fetus with CDH, consideration should be given to imaging evaluation of the neck to evaluate the cervical vascular anatomy, particularly in cases with poorer prognosis in whom it is anticipated that neonatal ECMO may be an option.

Internal jugular vein thrombosis associated with venous hypoplasia and protein S deficiency revealed by ultrasonography

A 41-year-old woman, who had no thrombotic risk factors and past history except congenital scoliosis, underwent central venous catheterization (CVC) before correction of the scoliosis. When internal jugular vein (IJV) catheterization using the anatomical landmark technique failed, CVC under ultrasound guidance was tried. As a consequence, thrombosis and hypoplasia of the right IJV were incidentally detected by ultrasonography. Central venous catheters were then successfully placed in other veins under ultrasound guidance. Also, after examinations to rule out the possibility of pulmonary embolism and to clarify the causes of the IJV thrombosis, the patient was found to have protein S deficiency. CVC under ultrasound guidance should be recommended to prevent the failure of cannulation and complications such as thromboembolism in patients who could possibly have anomalies of vessels as a result of anatomical deformities caused by severe scoliosis, even if patients do not have thrombotic risk factors such as a history of central catheter insertion or intravenous drug abuse, cancer, advanced age, cerebral infarction, and left ventricular dysfunction. Also, if venous thrombosis is found in patients without predisposing risk factors, one should ascertain the cause of the hypercoagulable state, for example protein S deficiency, and perform appropriate treatment and prevention of venous thromboembolism.

[Ultrasound-guided central venous access in adults and children: Procedure and pathological findings]

Central venous line placement is a standard procedure in critical care and peri-operative medicine. This procedure can be associated with severe complications. In contrast to the landmark technique, ultrasound-guided punctures can significantly reduce the rate of complications. Patients with a high risk for difficult vascular access include critical care and emergency patients as well as patients on anticoagulation medication and dialysis. Placement of central venous catheters can be difficult in ventilated patients and if there has been prior surgery in the puncture area. In children and small infants central venous access can also be challenging due to the anatomical relationship in the head and neck region. Puncture techniques are explained briefly by means of ultrasound anatomy. Typical ultrasonographic images visualize pathological findings in order to identify dangers and complications in central venous catheterization.

The perfect crime? CCSVI not leaving a trace in MS

BACKGROUND

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system, believed to be triggered by an autoimmune reaction to myelin. Recently, a fundamentally different pathomechanism termed 'chronic cerebrospinal venous insufficiency' (CCSVI) was proposed, provoking significant attention in the media and scientific community.

METHODS

Twenty MS patients (mean age 42.2 ± 13.3 years; median Extended Disability Status Scale 3.0, range 0-6.5) were compared with 20 healthy controls. Extra- and intracranial venous flow direction was assessed by colour-coded duplex sonography, and extracranial venous cross-sectional area (VCSA) of the internal jugular and vertebral veins (IJV/VV) was measured in B-mode to assess the five previously proposed CCSVI criteria. IJV-VCSA ≤ 0.3 cm(2) indicated 'stenosis,' and IJV-VCSA decrease from supine to upright position 'reverted postural control.' The sonographer, data analyser and statistician were blinded to the patient/control status of the participants.

RESULTS

No participant showed retrograde flow of cervical or intracranial veins. IJV-VCSA ≤ 0.3 cm(2) was found in 13 MS patients versus 16 controls (p=0.48). A decrease in IJV-VCSA from supine to upright position was observed in all participants, but this denotes a physiological finding. No MS patient and one control had undetectable IJV flow despite deep inspiration (p=0.49). Only one healthy control and no MS patients fulfilled at least two criteria for CCSVI.

CONCLUSIONS

This triple-blinded extra- and transcranial duplex sonographic assessment of cervical and cerebral veins does not provide supportive evidence for the presence of CCSVI in MS patients. The findings cast serious doubt on the concept of CCSVI in MS.

Refeeding syndrome influences outcome of anorexia nervosa patients in intensive care unit: an observational study

Introduction

Data on the epidemiology and management of anorexia nervosa (AN) in the intensive care unit (ICU) are scarce. The aim of this study was to evaluate the prevalence and associated morbidity and mortality of AN in French ICUs.

Methods

We randomly selected 30 ICUs throughout France. Thereafter, we retrospectively analyzed all patients with AN admitted to any of these 30 ICUs between May 2006 and May 2008. We considered demographic data, diagnosis at admission and complications occurring during the stay, focusing on refeeding syndrome and management of refeeding.

Results

Eleven of the 30 ICUs participated in the retrospective study, featuring 68 patients, including 62 women. Average body mass index at the admission was 12 ± 3 kg/m2. Twenty one were mechanically ventilated, mainly for neurological reasons. The reported average calorie intake was 22.3 ± 13 kcal/kg/24 h. Major diagnoses at admission were metabolic problems, refeeding survey and voluntary drug intoxication and infection. The most common complications were metabolic, hematological, hepatic, and infectious events, of which 10% occurred during refeeding. Seven patients developed refeeding syndrome. At day one, the average calorie intake was higher for patients who developed refeeding syndrome (23.2 ± 5 Kcal/kg/j; n = 7) versus patients without refeeding syndrome (14.1 ± 3 Kcal/kg/j; n = 61) P = 0.02. Seven patients died, two from acute respiratory distress syndrome and five from multiorgan-failure associated with major hydroelectrolytic problems.

Conclusions

The frequency of AN in ICU patients is very low and the crude mortality in this group is about 10%. Prevention and early-detection of refeeding syndrome is the key point.

Estimation of the diameter and cross-sectional area of the internal jugular veins in adult patients

Introduction

Unawareness of an asymmetry between the right and left internal jugular vein (IJV) and methodological pitfalls in previous studies raise concerns about such asymmetry. Hence the aim of this prospective non-interventional study was to validate the hypothesis that right IJV diameter is greater than those of left IJV and to determine the cross-sectional area of the IJVs using computed tomography (CT)-scans and original automatic software.

Methods

All consecutive adult outpatients who underwent a thoracic contrast-enhanced (TCE) helical CT-scan during a 5-month period were included. To determine diameter and cross sectional area of the IJVs, we used Advanced Vessel Analysis software integrated in a CT-scan (Advanced Vessel Analysis on Advantage Workstation Windows 4.2; General Electrics) allowing automatic segmentation of vessels and calculation of their diameters and cross-sectional areas.

Results

A total of 360 TCE CT-scans was performed; 170 were excluded from the analysis. On the remaining 190 CT scans, the diameter and cross-sectional area of the right IJV were significantly greater than those of the left IJV (17 ± 5 mm [median: 17 mm, range: 13 to 20 mm] vs. 14 ± 5 mm [median: 13 mm, range: 10 to 16 mm], P < 0.001; and 181 ± 111 mm² [median: 160 mm², range: 108 to 235 mm²] vs. 120 ± 81 mm² [median: 102 mm², range: 63 to 168 mm²], P < 0.001, respectively).

Conclusions

In a general population of adult outpatients, the diameter and cross-sectional area of the right IJV were significantly greater than those of the left IJV. This could be an additional argument to prefer right over left IJV cannulation.