Anomalous Posterior Branching of the Internal Jugular Vein: A Report of Two Patients

The internal jugular vein (IJV) is an important vein encountered during most routine major head and neck surgeries. The IJV is known to infrequently present with anatomical variations, commonly duplication and fenestration. This report presents two cases that highlight an unusual anatomical variation of the IJV, namely the posterior tributary, which was encountered during neck dissection for papillary carcinoma of the thyroid and metastatic cervical lymph nodes. The first case was a 50-year-old woman with papillary carcinoma of the thyroid and regional metastasis, who underwent extensive neck dissection. During dissection, an anomalous posterior tributary of the IJV was discovered, originating around 3 cm above the omohyoid tendon-IJV junction. In case 2, a 40-year-old woman with a history of thyroidectomy exhibited a similar anomaly during neck dissection. In both cases, the posterior tributary was observed branching into two divisions. These cases emphasize the significance of recognizing anatomical variations to avoid inadvertent damage during surgical procedures. Anomalies like the posterior IJV tributary could have implications for surgical planning, emphasizing the importance of thorough exploration and understanding of individual variations. Awareness of such variations will help facilitate surgeons in safely performing neck dissections.

Interposition of great saphenous vein on lymphatic venous anastomosis for infantile intractable chylothorax

Central lymphatic diseases such as intractable chylothorax can be fatal. Lymphatic venous anastomosis at the venous angle level is expected to give a direct therapeutic effect because it opens the obstructed outlet of the main lymphatic vessels. However, the original methods resulted in some important issues, such as the potential for venous reflux. In the present case, we modified the original anastomosis method by interposing a vein graft with venous valves to increase the distance and prevent venous reflux. Collecting the lymphatic flow resulted in termination of the chylothorax with preserved postoperative patency for years, without any complications, including at the graft-harvested extremity.

Reliability of point-of-care ultrasound to evaluate fluid tolerance performed by critical care residents

BACKGROUND

Patients with hypotension usually receive intravenous fluids, but only 50% will respond to fluid administration. We aimed to assess the intra and interobserver agreement to evaluate fluid tolerance through diverse ultrasonographic methods.

METHODS

We prospectively included critically ill patients on mechanical ventilation. One trained intensivist and two intensive care residents obtained the left ventricular outflow tract velocity-time integral (VTI) variability, inferior vena cava (IVC) distensibility index, internal jugular vein (IJV) distensibility index, and each component of the venous excess ultrasound (VExUS) system. We obtained the intraclass correlation coefficient (ICC) and Gwet's first-order agreement coefficient (AC1), as appropriate.

RESULTS

We included 32 patients. In-training observers were unable to assess the VTI-variability in two patients. The interobserver agreement was moderate to evaluate the IJV-distensibility index (AC1 0.54, CI 95% 0.29-0.80), fair to evaluate VTI-variability (AC1 0.39, CI 95% 0.12-0.66), and absent to evaluate the IVC-distensibility index (AC1 0.19, CI 95% - 0.07 to 0.44). To classify patients according to their VExUS grade, the intraobserver agreement was good, and the interobserver agreement was moderate (AC1 0.52, CI 95% 0.34-0.69).

CONCLUSIONS

Point-of-care ultrasound is frequently used to support decision-making in fluid management. However, we observed that the VTI variability and IVC-distensibility index might require further training of the ultrasound operators to be clinically useful. Our findings suggest that the IJV-distensibility index and the VExUS system have acceptable reproducibility among in-training observers.

Guidewire insertion into the vertebral vein during right internal jugular vein central venous catheterization -A rare case report

BACKGROUND

Internal jugular veins are the most frequently accessed site for central venous catheterization in patient management, whereas complications involving vertebral veins are a rare occurrence.

CASE

A 73-year-old male suspected to have a urothelial carcinoma was scheduled for elective left nephroureterectomy. During central venous catheterization using the anatomic landmark technique to target the internal jugular vein, a guidewire is inadvertently inserted into the suspected vertebral vein. Following the correction of the catheterization, a radiologist reviewed the preoperative enhanced computed tomography and confirmed that the initially punctured vessel was the vertebral vein. On the third day after surgery, the central venous catheter was removed, and the patient did not exhibit any complications, such as bleeding, swelling, and neurological symptoms.

CONCLUSIONS

The use of ultrasonography during central venous catheterization is recommended to evaluate the anatomy of the puncture site and prevent misinsertion of the catheter, which can lead to several complications.

Bedside ultrasound of the internal jugular vein to assess fluid status and right ventricular function: The POCUS-JVD study

BACKGROUND

Accurate estimation of fluid status is important in the management of heart failure patients, however, the current methods for bedside assessment can be unreliable or impractical for daily use.

METHODS

Non-ventilated patients were enrolled immediately prior to scheduled right heart catheterization (RHC). Using M-mode, IJV maximum (Dmax) and minimum (Dmin) anteroposterior diameters were measured during normal breathing, while supine. Respiratory variation in diameter (RVD) was calculated as [(Dmax - Dmin)/Dmax] in percentage. Collapsibility with sniff maneuver (COS) was assessed. Lastly, inferior vena cava (IVC) was assessed. Pulmonary artery pulsatility index (PAPi) was calculated. Data was obtained by five investigators.

RESULTS

Total 176 patients were enrolled. Mean BMI was 30.5 kg/m2, LVEF 14-69% (range), 38% with LVEF ≤35%. The POCUS of IJV could be performed in all patients in <5 min. Increasing RAP demonstrated progressive increase in IJV and IVC diameters. For high filling pressure (RAP ≥10 mmHg), an IJV Dmax ≥1.2 cm or IJV-RVD < 30% had specificity >70%. Combining the POCUS of IJV to physical examination improved the combined specificity to 97% for RAP ≥10 mmHg. Conversely, a finding of IJV-COS was 88% specific for normal RAP (<10 mmHg). An IJV-RVD <15% is suggested as a cutoff for RAP ≥15 mmHg. The performance of IJV POCUS was comparable to IVC. For RV function assessment, IJV-RVD < 30% had 76% sensitivity and 73% specificity for PAPi <3, while IJV-COS was 80% specific for PAPi ≥3.

CONCLUSION

POCUS of IJV is an easy to perform, specific and reliable method for volume status estimation in daily practice. An IJV-RVD < 30% is suggested for estimation of RAP ≥10 mmHg and PAPi <3.

Clinical Significance of Physical Examination for Hypertrophic Cardiomyopathy

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) show various physical findings, but their clinical significance has not been systematically evaluated.Methods and Results: This study evaluated 105 consecutive patients with HCM who had undergone phonocardiography and external pulse recording. Physical examinations included a visible jugular a-wave (Jug-a), audible 4th sound (S4), and double or sustained apex beat. The primary outcome was a composite of all-cause death and hospitalization for cardiovascular disease. A total of 104 non-HCM subjects served as controls. The prevalence of visible Jug-a in the seated or supine position, audible S4, and a sustained or double apex beat in patients with HCM were 10%, 71%, 70%, 42%, and 27%, respectively, all of which were significantly higher than in the controls (0%, 20%, 11%, 17%, and 2%; P<0.001 for all comparisons). The combination of visible Jug-a in the supine position and audible S4 yielded a specificity of 94% and sensitivity of 57%. During a follow-up period of 6.6 years, 6 patients died and 10 were hospitalized. The absence of audible S4 was a predictor of cardiovascular events (hazard ratio, 3.91; 95% confidence interval, 1.41 to 10.8; P=0.005).

CONCLUSIONS

Detection of these findings has clinical importance in the diagnosis and risk stratification of HCM prior to the use of advanced imaging techniques.

Contrast analysis in ultrafast ultrasound blood flow imaging of jugular vein

PURPOSE

The contrasts of flowing blood in in vitro experiments using porcine blood and in vivo measurements of human jugular veins were analyzed to demonstrate that the hemorheological property was dependent on the shear rate.

METHODS

Blood samples (45% hematocrit) suspended in saline or plasma were compared with examine the difference in viscoelasticity. Ultrafast plane-wave imaging at an ultrasonic center frequency of 7.5 MHz was performed on different steady flows in a graphite-agar phantom. Also, in vivo measurement was performed in young, healthy subjects and patients with diabetes. A spatiotemporal matrix of beamformed radio-frequency data was used for the singular value decomposition (SVD) clutter filter. The clutter-filtered B-mode image was calculated as the amplitude envelope normalized at the first frame in the diastolic phase to evaluate contrast. The shear rate was estimated as the velocity gradient perpendicular to the lateral axis.

RESULTS

Although nonaggregated erythrocytes at a high shear rate exhibited a low echogenicity, the echogenicity in the plasma sample overall increased due to erythrocyte aggregation at a low shear rate. In addition, the frequency of detection of specular components, defined as components beyond twice the standard deviation of a contrast map obtained from a clutter-filtered B-mode image, increased in the porcine blood at a high shear rate and the venous blood in healthy subjects versus patients with diabetes.

CONCLUSION

The possibility of characterizing hemorheological properties dependent on the shear rate and diabetes condition was indicated using ultrafast plane-wave imaging with an SVD-based clutter filter.

Trendelenburg position for internal jugular vein catheterization: A systematic review and meta-analysis

To determine the effect of Trendelenburg position on the diameter or cross-section area of the internal jugular vein (IJV) a systematic review and metanalysis was performed. Studies that evaluated the cross-sectional area (CSA) and anteroposterior (AP) diameter of the right internal jugular vein (RIJV) with ultrasonography in supine and any degree of head-down tilt (Trendelenburg position) were analyzed. A total of 22 articles (613 study subjects) were included. A >5° Trendelenburg position statistically increases RIJV CSA and AP diameter. Further inclination from 10° does not statistically benefit IJV size. This position should be recommended for CVC placement, when patient conditions allow it, and US-guided cannulation is not available.

The influence of serial 50 μL microsampling on rats administered azathioprine, the immunosuppressive drug

According to the ICH S3A Q&A, microsampling is applicable to pharmaceutical drugs and toxicological analysis. Few studies have reported the effect of microsampling on the toxicity of immunotoxicological drugs. The aim of this multicenter study was to evaluate the toxicological effects of serial microsampling on rats treated with azathioprine as a model drug with immunotoxic effects. Fifty microliters of blood were collected from the jugular vein of Sprague-Dawley rats at six time points from day 1 to 2 and 7 time points from day 27 to 28. The study was performed at three organizations independently. The microsampling effect on clinical signs, body weights, food consumption, hematological parameters, biochemical parameters, urinary parameters, organ weights, and tissue pathology was evaluated. Azathioprine-induced changes were observed in certain hematological and biochemical parameters and thymus weight and pathology. Microsampling produced minimal or no effects on almost all parameters; however, at 2 organizations, azathioprine-induced changes were apparently masked for two leukocytic, one coagulation, and two biochemical parameters. In conclusion, azathioprine toxicity could be assessed appropriately as overall profiles even with blood microsampling. However, microsampling may influence azathioprine-induced changes in certain parameters, especially leukocytic parameters, and its usage should be carefully considered.

Terminal bifurcation of the external jugular vein: a rare variation

Variations of external jugular vein are common. Here, we present a rare terminal bifurcation of the left external jugular vein. The left external jugular vein was formed by the union of entire retromandibular vein and posterior auricular vein. One inch above the clavicle, it bifurcated into medial and lateral divisions. The medial division terminated into the internal jugular vein and the lateral division terminated into the subclavian vein. Medial division received a common vein formed by the union of anterior jugular vein and an anonymous vein lying under the sternocleidomastoid muscle. The lateral division received a common vein formed by the union of suprascapular and transverse cervical veins. The knowledge about this variation could be useful to head and neck surgeons, radiologists and plastic surgeons.

The Role of Non Invasive Diagnosis of Internal Jugular Vein Phlebectasia

Phlebectasia is the abnormal saccular fusiform dilatation (without tortuosity) of a vein, which may affect any vein. Its etiology remains unknown and it is seen usually in the pediatric age group as a unilateral lower neck swelling, mostly on the right side. The other differential diagnoses of the neck swellings which increase in size during a Valsalva manoeuver are tumors or cysts of the upper mediastinum, external laryngeal diverticulum or laryngoceles. Our case report has highlighted the importance of understanding the nature of this lesion by using non-invasive radiological diagnostic modalities (USG), in order to avoid invasive investigations which can lead to catastrophic results. Case report. We describe a case of five year old boy with history of inguinal hernia repair a year ago presented with intermittent right sided neck swelling since he was two years old. His examination at rest was normal. However, with the Valsalva manoeuver a soft, painless, compressible swelling which appeared in the right lower neck was seen, which was not attached to the deep structures. Flexible nasopharyngolaryngoscope revealed normal laryngeal finding. Initial ultrasound finding revealed normal looking cervical lymph nodes bilaterally with no suspicious cystic lesion or collection. Patient then arranged for MRI neck where there are multiple bilateral subcentimeter cervical lymph nodes. However, repeated ultrasound neck while performing Valsalva manoeuver by patient showed sonographic features in keeping with bilateral internal jugular veins phlebectasia. Patient then was referred to pediatric surgeon for further management. A clinical diagnosis can be achieved by having a strong suspicion about this intermittent neck mass. It should be evaluated with non-invasive radiological modalities to avoid the possible catastrophic results which result from invasive techniques.

No obvious toxicological influences of 50 μL microsampling from rats administered phenacetin as a drug with hematological toxicity

According to ICH S3A Q&A focusing on microsampling, its application should be avoided in main study animals for test drugs that could exacerbate hematological parameters with frequent blood sampling. However, no study has reported the effects of microsampling on toxicity parameters of drugs known to induce hematological toxicity. Therefore, we assessed the toxicological effects of serial microsampling on rats treated with phenacetin as a model drug. In a common 28-day study, 50 µL of microsampling was performed at 6-time points on days 1 to 2 and 7-time points on days 27 to 28 from the jugular vein of Sprague Dawley rats. The study was performed independently by two organizations. The toxicological influence of microsampling was evaluated on body weight, food consumption, hematology, blood clinical chemistry, urine parameters, organ weights, and tissue pathology. Phenacetin treatments induced significant changes of various hematological parameters (including hemoglobin and reticulocytes), some organ weights (including liver and spleen), and some hematology-related pathological parameters in the liver, spleen and bone marrow. Meanwhile, serial microsampling exhibited minimal influence on the assessed parameters, although 20 parameters showed statistical differences mostly at one organization. The current results support the notion that serial 50 μL microsampling from the jugular vein had minimal impacts on overall toxicological profiles even in rats treated with a drug inducing hematological toxicity, but the potential adverse effect on certain parameters could not be fully excluded. Accordingly, this microsampling technique has possibility to be employed even for non-clinical rat toxicity studies using drugs with potentially hematological toxicity.

The prevalence and clinical associations of ultrasound measures of congestion in patients at risk of developing heart failure

AIMS

Congestion is a cardinal feature of untreated heart failure (HF) and might be detected by ultrasound (US) before overt clinical signs appear.

METHODS AND RESULTS

We investigated the prevalence and clinical associations of subclinical congestion in 238 patients with at least one clinical risk factor for HF (diabetes, ischaemic heart disease, or hypertension) using three US variables: (i) inferior vena cava (IVC) diameter; (ii) jugular vein distensibility (JVD) ratio (the ratio of the jugular vein diameter during the Valsalva manoeuvre to that at rest); (iii) the number of B-lines from a 28-point lung US. US congestion was defined as IVC diameter > 2.0 cm, JVD ratio < 4.0 or B-lines count > 14. The prevalence of subclinical congestion (defined as at least one positive US marker of congestion) was 30% (13% by IVC diameter, 9% by JVD ratio and 13% by B-line quantification). Compared to patients with no congestion on US, those with at least one marker had larger left atria and higher plasma concentrations of natriuretic peptides. Patients with raised plasma N-terminal pro-B-type natriuretic peptide/B-type natriuretic peptide had a lower JVD ratio (7.69 vs. 8.80; P = 0.05) and more often had at least one lung B-line (74% vs. 63%; P = 0.05). However, plasma natriuretic peptide concentrations were more closely related to left atrial volume than other US measures of congestion.

CONCLUSIONS

Subclinical evidence of congestion by US is common in patients with clinical risk factors for HF. Whether these measurements provide additional value for predicting the development of HF and its prevention deserves consideration.

Central venous catheterization site choice based on anatomical landmark technique: a systematic review and meta-analysis

BACKGROUND

Internal jugular vein catheterization (IJVC) and subclavian vein catheterization (SCVC) have been the most preferred central venous catheterizations (CVC) clinically. Individual preference and institutional routine dominate the traditional CVC choice; however, it is lack of high-level evidence. We sought to provide better clinical strategy for CVC site choice based on anatomical landmark technique between IJVC and SCVC.

METHODS

We systematically reviewed eligible studies from PubMed, OVID, Cochrane and ClinicalTrials.Gov till February 2020. The primary outcomes were catheterization time and overall success rate, and the secondary outcomes were the first-attempt success rate and the instant mechanical complications. Ethical problems are not applicable.

RESULTS

A total of 3378 patients from 7 studies were included in the analyses. Neither difference was found on the catheterization time (SMD 95% CI: -0.095-0.124, p = 0.792), nor any difference on the overall success rate (RR = 1.017, 95% CI: 0.927-1.117, p = 0.721, I² = 89.6%) between the 2 procedures. However, subgroup analyses showed overall success rate of IJVC was significantly lower than that of SCVC (RR = 0.906, 95% CI: 0.850-0.965, p = 0.002) in adults. The first-attempt success rate of IJVC group was higher in the adults (RR = 1.472, 95% CI: 1.004-2.156, p = 0.047). No significance was detected in arterial injury (RR = 1.137, 95% CI: 0.541-2.387, p = 0.735) and pneumothorax (RR = 0.600, 95% CI: 0.32-1.126, p = 0.112) between the two procedures. Hematoma was significantly more in IJVC group than that in SCVC group (RR = 2.824, 95% CI: 1.181-6.751, p = 0.02).

CONCLUSIONS

Compared with IJVC, SCVC shows a higher overall success rate while a lower first-attempt success rate in adults, and has involved with less hematoma.

PROSPERO REGISTRATION

CRD42020165444.

Postural Regulation of Intracranial Pressure: A Critical Review of the Literature

INTRODUCTION

Mechanisms underlying postural regulation of ICP remain unclear.

METHOD

Literature review in Medline 1900-2019 with search terms "Intracranial pressure," "Posture," "Jugular vein," "Collapse," "Regulation," "Physiology," resulting in 40 selected papers.

RESULTS

Postural transition from supine to sitting position results in a biphasic decrease of ICP: a fast decrease during phase 1 (low tilt) followed by a stabilization during phase 2 (higher tilt/erect). Two main factors have been proposed to explain this decrease: (a) Fast CSF transfers from the non-distensible cranial compartment to the distensible spinal compartment during phase 1; the maximal spinal expansion corresponds to phase 2; (b) The gravitational effect within the venous system is transferred to the CSF system according to Davson's equation, modulated by jugular collapse that would be responsible for the stabilization of ICP decrease in phase 2.

DISCUSSION

The impact of CSF transfers, from the cranial to spinal compartment, on postural regulation of ICP, has been well documented. Although they are sophisticated, models that support the major influence of jugular collapse likely underestimate the role of the vertebral venous plexus in cerebral venous outflow in the upright position. Moreover, Davson's equation supports slow CSF transfer from subarachnoid spaces to the venous system (a few mL/min) and thus cannot explain fast postural modulation of ICP (in a few seconds). Further data are thus needed to better understand postural regulation of ICP.

Malignant meningioma with jugular vein invasion and carotid artery extension: A case report and review of the literature

BACKGROUND

Grade II and III meningiomas [World Health Organization (WHO) classification] rarely have extracranial metastases via the blood circulation; however, we experienced a case with a metaplastic atypical meningioma and local de-differentiation that metastasized to the jugular vein, carotid artery and subclavian artery at the cervicothoracic junction. Such cases have seldom been reported before.

CASE SUMMARY

The patient was a 30-year-old man who developed right neck masses with dysphagia, labored breathing, dizziness, and occasional earaches. Eight months earlier the patient was diagnosed with a right parietal lobe neoplasm and hemorrhage at a local hospital due to the sudden onset of headaches and left limb weakness, and the post-operative pathology was a metaplastic atypical meningioma (WHO grade II) with local de-differentiation (WHO III). Magnetic resonance imaging revealed a calcified mass at the root of the neck on the right and a large cystic mass in the right parapharyngeal space. Head and neck angiography showed that the right common carotid artery was compressed and completely occluded, and the jugular vein was enveloped by the tumor and occluded. A balloon occlusion test showed no perfusion in the right common carotid artery. Tumor resection, carotid artery ligation, and subclavian artery reconstruction were performed. The tumor was a malignant meningioma. Post-operatively, the patient had Horner's syndrome and hoarseness.

CONCLUSION

This case highlights the importance of the link between a large cervical mass and a primary intracranial tumor. Malignant meningioma should not be considered merely as an intracranial metastasis spread through cerebrospinal fluid, it can also be transferred through the circulation to the parapharyngeal space and the cervical great vessels.

Air in the right ventricle and vein after basilar skull fracture: a case report

Background

Air in the venous system may cause vascular air embolism, which is a potentially life-threatening event. The presence of air in venous system after basilar skull fracture is very rare.

Case presentation

A 77-year-old man fell from a truck bed and suffered head and neck trauma. On hospital arrival, his consciousness was clear and his vital signs were stable. His chief complaint was pain in the back of his head and neck. Head CT showed traumatic subarachnoid hemorrhage in the right frontal area and basilar skull fracture of the occipital bone. Whole body CT showed pneumocephalus and air in the jugular vein and right ventricle. The patient was placed in the supine position in a state of absolute rest to prevent vascular air embolism and was treated conservatively. On hospital day 3, CT was reperformed, revealing disappearance of air in the right ventricle and decreased air in the veins of the head and neck. On hospital day 4, the air in the veins disappeared completely on CT. He did not experience vascular air embolism after increasing of his activity level (e.g., raising his head on hospital day 3 and standing and walking alone on day 5). He was discharged 34 days after admission without sequelae.

Conclusions

Head trauma patients with basilar skull fracture might develop vascular air embolism if physicians fail to detect air in the venous system on hospital arrival. A high degree of suspicion regarding air in venous system or heart is required when patients present with such injuries.

Ultrasound imaging of congestion in heart failure: examinations beyond the heart

Congestion, related to pressure and/or fluid overload, plays a central role in the pathophysiology, presentation and prognosis of heart failure and is an important therapeutic target. While symptoms and physical signs of fluid overload are required to make a clinical diagnosis of heart failure, they lack both sensitivity and specificity, which might lead to diagnostic delay and uncertainty. Over the last decades, new ultrasound methods for the detection of elevated intracardiac pressures and/or fluid overload have been developed that are more sensitive and specific, thereby enabling earlier and more accurate diagnosis and facilitating treatment strategies. Accordingly, we considered that a state-of-the-art review of ultrasound methods for the detection and quantification of congestion was timely, including imaging of the heart, lungs (B-lines), kidneys (intrarenal venous flow), and venous system (inferior vena cava and internal jugular vein diameter).

Determination of dexmedetomidine using high performance liquid chromatography coupled with tandem mass spectrometric (HPLC-MS/MS) assay combined with microdialysis technique: Application to a pharmacokinetic study

Dexmedetomidine, as a safe sedative, mainly exerts on the central nervous system particularly in the locus coeruleus producing arousable sedation with potential analgesic and anxiolytic effects. The quantification and pharmacokinetic investigation of dexmedetomidine in the central nervous system have been described rarely. In order to estimate the unbound dexmedetomidine concentrations in brain extracellular fluid and blood simultaneously, we employed microdialysis technique as a sampling method and primarily established a rapid, sensitive and selective high-performance liquid chromatography coupled with tandem mass spectrometry method (HPLC-MS/MS). Dexmedetomidine and the internal standard (dexmedetomidine-d4) were extracted in liquid-liquid extraction procedure with ethyl acetate from 10 μL of alkalinized microdialysate sample. After evaporation under nitrogen at room temperature, the analytes were reconstituted in acetonitrile and transferred to be detected. HPLC was performed on an Agilent Poroshell 120 Hilic column (4.6 × 100 mm, 2.7 μm) with isocratic elution at a flow rate of 0.3 mL/min by 0.1% formic acid/acetonitrile (60:40, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction monitoring (MRM) mode using the respective [M⁺H]⁺ ions m/z 201.2 to m/z 95.1 for DEX and m/z 205.2 to m/z 99.1 for IS (DEX-d4). The concentration-response relationship was of good linearity over a concentration range of 1.00-1000.00 ng/mL with the correlation coefficient above 0.999. The lower limit of quantification was 1.00 ng/mL with a relative standard deviation of less than 20%. The intra- and inter-day accuracy were within ±5.00% and precision was <7.23%. The recoveries of dexmedetomidine in microdialysates were 76.61-93.38%. The validated HPLC-MS/MS method has been successfully applied to study the pharmacokinetics of dexmedetomidine in rats after a caudal vein administration.

Lack of toxicological influences by microsampling (50 µL) from jugular vein of rats in a collaborative 28-day study

Due to finalization of the ICH S3A Q&A focusing on microsampling, application of microsampling technique to regular non-clinical animal studies is expected for non-clinical safety assessment of pharmaceuticals. In Europe, microsampling from the tail vein or saphenous vein has often been used, whereas sampling from the jugular vein is thought to be more common for non-clinical studies in Japan. Therefore, we assessed the toxicological effects of serial microsampling from the jugular vein of SD rats in a common 28-day study at 4 independent organizations. Fifty microliter sampling was performed at 6 timepoints on day 1 to 2 and 7 timepoints on day 27 to 28 and its toxicological influences on body weight, food consumption, hematological and clinical chemistry parameters, and organ weights (on day 29 for 3 and day 28 for 1 organizations) were evaluated. The serial microsampling was shown to have no or minimal influences on the assessed parameters. The observed statistical differences for the 18 parameters were sporadic and did not appear to be systemically associated with microsampling. However, the sporadic changes were more often observed in females (14/18 parameters) than in males (6/18), suggesting the possibility that female rats were more susceptible to treatment-based influences. The current results indicate that serial 50 μL sampling from the jugular vein of SD rats had no or very slight toxicological effects, suggesting that this microsampling condition is applicable for toxicokinetic evaluation of non-clinical rat toxicity studies.

Expression profiles of the internal jugular and saphenous veins: Focus on hemostasis genes

INTRODUCTION

Venous bed specificity could contribute to differential vulnerability to thrombus formation, and is potentially reflected in mRNA profiles.

MATERIALS AND METHODS

Microarray-based transcriptome analysis in wall and valve specimens from internal jugular (IJV) and saphenous (SV) veins collected during IJV surgical reconstruction in patients with impaired brain outflow. Multiplex antigenic assay in paired jugular and peripheral plasma samples.

RESULTS

Most of the top differentially expressed transcripts have been previously associated with both vascular and neurological disorders. Large expression differences of HOX genes, organ patterning regulators, pinpointed the vein positional identity. The "complement and coagulation cascade" emerged among enriched pathways. In IJV, upregulation of genes for coagulation inhibitors (TFPI, PROS1), activated protein C pathway receptors (THBD, PROCR), fibrinolysis activators (PLAT, PLAUR), and downregulation of the fibrinolysis inhibitor (SERPINE1) and of contact/amplification pathway genes (F11, F12), would be compatible with a thromboprotective profile in respect to SV. Further, in SV valve the prothrombinase complex genes (F5, F2) were up-regulated and the VWF showed the highest expression. Differential expression of several VWF regulators (ABO, ST3GAL4, SCARA5, CLEC4M) was also observed. Among other differentially expressed hemostasis-related genes, heparanase (HPSE)/heparanase inhibitor (HPSE2) were up-/down-regulated in IJV, which might support procoagulant features and disease conditions. The jugular plasma levels of several proteins, encoded by differentially expressed genes, were lower and highly correlated with peripheral levels.

CONCLUSIONS

The IJV and SV rely on differential expression of many hemostasis and hemostasis-related genes to balance local hemostasis, potentially related to differences in vulnerability to thrombosis.

Idiopathic bilateral jugular phlebectasia in a 9-year-old boy

A nine-year-old boy came to our clinic for the appearance of a voluminous swelling at the base of the neck in the jugular area after coughing. He underwent fibroscopy and a contrast-enhanced chest computed tomography (CT) scan, which did not indicate pathological findings even during the Valsalva maneuvre. After a color-Doppler ultrasound of the epiaortic vessels was obtained, a diagnosis of idiopathic phlebectasia of the internal jugular veins was made. The cause of the jugular phlebectasia remains unclear, and no treatment is indicated for this rare, benign, and self-limiting condition.

Ten-year experience of Q fever endocarditis in a tertiary cardiac center in Saudi Arabia

BACKGROUND

Q fever endocarditis (QFE) is considered rare in the Middle East, with only a few cases reported in Saudi Arabia. The aim of this study is to report on the experience of our centre on QFE.

METHODS

We searched the medical records for cases of QFE at our cardiac center from 2009-2018. Demographic data, clinical features, serology and echocardiography results, treatments, and outcomes were assessed.

RESULTS

Five hundred and two cases of infective endocarditis were detected over the 10 years period. Among the 234 patients with blood culture-negative endocarditis (BCNE), 19 (8.10%) had QFE. All patients had a previously diagnosed congenital heart disease except for one patient with rheumatic heart disease. Eleven patients had received a bovine jugular vein-related implant, e.g., a Melody valve (seven patients) or Contegra conduit (four patients). Coinfection was detected in three patients, and immunologic and embolic phenomena were observed in five patients. All patients received a combination of hydroxychloroquine and doxycycline, with good outcomes. Only two patients required surgery while on treatment. Two patients died several months after treatment; the cause of death was not identified.

CONCLUSION

This study indicates that Q fever exists in our population. The majority of the patients had congenital heart disease (CHD) and underwent bovine jugular vein implants. Patients with CHD are at increased risk of infective endocarditis. Bovine jugular vein implants increase the risk of infective and possibly QFE. Proper exclusion of Q fever is warranted in all BCNE and possibly in culture-positive endocarditis cases in areas endemic to Q fever.

KEY POINTS

We presented the largest series of Q fever endocarditis cases in Saudi Arabia. We showed that Q fever is not rare in the Middle East and suggest that it should be considered in all blood culture-negative endocarditis cases.

Children with posterior semicircular canal dehiscence: A case series

Posterior semicircular canal dehiscence is a rare condition and can cause a variety of symptoms. We report three cases of children between 5 and 12 years of age with a PSCD. They all presented with different complaints as follows: Tullio phenomenon in the first case, conductive hearing loss in the second and, conductive hearing loss and pulsatile tinnitus in the third. Imaging showed in all cases a PSCD on the right side, caused by a prominent jugular bulb (high riding bulb). We describe the clinical, audiometric and radiological findings, and discuss the management and therapy. A conservative "wait and see" approach is recommended, especially with children, because of the possible complications of surgery and the possibility that the symptoms will lessen with the skull base osseous maturation.

Phlebectasia of Internal Jugular Vein- A Rare Differential Case of Neck Swelling With Review of Literature

INTRODUCTION

Internal jugular vein ectasia is a condition in which there is a dilatation of the internal jugular vein. A patient usually presents in the first decade with swelling in the neck, which aggravates in size while straining or coughing. This is a very rare condition and the chances of misdiagnosis are quite high. It is diagnosed by proper history taking, examination, and radiological study.

CASE REPORT

We reported the case of a seven-year-old female presenting with right-sided swelling in the neck aggravating in size while straining or coughing. Regular follow-up was advised. Swelling regression was observed after one year of follow-up without any surgical treatment.

CONCLUSION

This is a self-limiting condition and usually the treatment is not warranted. Regular follow-up is advised for the patient.

[Diagnosis and treatment of jugular vein thrombosis]

Thromboses in the head and neck region are rare events, particularly in the internal jugular vein. However, they can result in potentially hazardous complications. Possible triggers are inflammatory, traumatic, and (para-)neoplastic diseases. Clinical symptoms often are non-specific, and it is thus important to even consider the possibility of an internal jugular vein thrombosis. Sonography is the diagnostic tool of choice, which can be complemented by CT/MRI if necessary. Depending on the individual etiology, antithrombotic treatment including modern direct oral anticoagulants (DOAC) is advisable. In cases of sepsis, surgery is mandatory to control the focus. However, there is hardly any evidence concerning this unusual problem due to the low incidence.

The method of long-term catheterization of the vena jugularis in pigs

INTRODUCTION

The pig is one of the most valuable in vivo models in biomedical research, however with only a few well-accessible veins suitable for venipuncture. Moreover, most of the known methods of blood collection are suitable only for a limited time period. The aim of the study was to verify an improved method of long-term catheterization of the jugular vein in pigs.

METHODS

A 420 mm polyurethane catheter 16G tube was surgically inserted using the Seldinger technique. The part of the tube that was not inserted into the vein was threaded through a subcutaneously introduced trocar into the occipital area, where it was well accessible and well protected from damage. The catheters were flushed with sterile 0.9% saline solution and locked with 4% citrate between frequent blood samplings, or with 30% citrate at intervals of 1-2-days. Once a week, the catheters were locked with 4% citrate containing taurolidine for 24 h in order to prevent infection. The method was verified in 14 pigs.

RESULTS

The catheters were fully functional for up to 11 weeks and no infection or thrombus was observed.

DISCUSSION

This method of catheterization and catheter care allows the realization of long-term experiments with comfortable and stress-free blood sampling.

Ultrasonic identification of internal jugular vein fenestration

OBJECTIVE

Anatomic variations have curicial importance during neck surgery. We present a fenestrated internal jugular vein variation and the accessory nerve passing through it. Also, we discuss preoperative diagnosis of this variation using ultrasonography.

METHOD

The possible recognition of this variation by ultrasonography is introduced.

RESULTS

The accessory nerve in an internal jugular vein fenestration can be seen using ultrasonography.

CONCLUSION

Preoperative identification of this rare variation may secure surgeon from potential complications.

In Vivo Measurement of H2S, Polysulfides, and "SSNO- Mix"-Mediated Vasoactive Responses and Evaluation of Ten Hemodynamic Parameters from Rat Arterial Pulse Waveform

The chapter describes protocols and pitfalls in in vivo studies of drug effects on anesthetized rats. It focuses on the preparation of Na₂S, Na₂S₄, and "SSNO^- mix" solutions for rat intravenous administration, surgical preparation of jugular vein for drug administration, and preparation of carotid and tail arteries for recording of arterial pulse waveform (APW) at high resolution. It describes evaluation of ten hemodynamic parameters from APW and measurement of apparent pulse wave velocity.

Sample Collection

Results may be changed with suboptimal sample collection and transport, which then result in incorrect diagnoses. Quality management of samples must start in the patient, extend through sampling itself, include appropriate short transport, and then be correctly accessioned at the referral laboratory or in-house station to ensure accurate diagnosis of disease. A quality assurance plan at the laboratory chosen is mandatory under American Society for Veterinary Clinical Pathology guidelines.

How useful is ultrasound guidance for internal jugular venous access in children?

PURPOSE

The aim of this study was to determine whether US reduces number of puncture attempts, procedure time, and complication rate during IJV access in children.

METHODS

A prospective study was performed in children (age ≤18years) admitted to our institution, from September 2013 to July 2014, with indications for central venous access. Patients meeting the inclusion criteria were randomized to the US-guided or control groups. The same physician performed all IJV cannulations in both groups. The end-points for comparison were: length of time to venous access, number of attempts, and rate of complications.

RESULTS

Fifty-one patients were included: 23 in the US-guided group and 28 in the control group. There were no between-group differences in weight, age, or sex. In the US-guided group, the number of punctures needed to achieve IJV access (median [interquartile range], 3 [2-5] vs. 1 [1, 2]; P<0.001), time to achievement of venous access, and complication rate (39% vs. 4.3%, P<0.009) were significantly lower.

CONCLUSION

US guidance is a useful adjunct to central venous access in children, facilitating the procedure, decreasing time to cannulation, and increasing safety.

TYPE OF STUDY

Prospective randomized study.

LEVEL OF EVIDENCE

1.

Patency of common carotid artery and internal jugular vein after a simple vessel sparing cannulation for extracorporeal membrane oxygenation support

BACKGROUND

Common carotid artery and internal jugular vein are commonly cannulated for establishment of peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) support. We present our results of a vessel sparing cannulation technique for neck vessels, which helps maintain vessel patency after decannulation.

METHODS

All patients who underwent ECMO, between January 2004 and January 2013 at a single center, were retrospectively reviewed. Follow up data for the patency of common carotid artery (CCA) and internal jugular vein (IJV) after decannulation were recorded.

RESULTS

Twenty-four consecutive patients who were successfully decannulated after VA ECMO support who underwent vessel sparing cannulation were retrospectively reviewed. Follow up data were unavailable in 4 and 1 patient did not survive. Amongst the remaining 19 patients the median duration of ECMO support in the remaining was 7 (IQR; 4-10) days. Follow up studies documenting vessel patency were available for IJV in 18 patients and CCA in 14 patients. At a median follow up of 137days (IQR; 35-7240) 15 (78%) patients had patent IJVs and 14 (100%) patients had patent CCAs.

CONCLUSION

The simple vessel sparing technique is effective in allowing restoration of the patency of the neck vessels after ECMO decannulation.

LEVEL OF EVIDENCE

Case series with no comparison group (Level IV).

Single-stick tunneled central venous access using the jugular veins in infants weighing less than 5 kg

BACKGROUND

Despite the demonstrated feasibility of the single-stick technique in the femoral vein, its use in neonates and infants for placing central lines in internal and external jugular veins has not been reported.

OBJECTIVE

Describe and assess the safety and efficacy of tunneled jugular central venous catheter placement performed under ultrasound (US) and fluoroscopic guidance in neonates and infants weighing <5 kg using the single-stick technique at three tertiary pediatric hospitals.

MATERIALS AND METHODS

Thirty-three children weighing less than 5 kg received tunneled central venous access in either internal or external jugular veins using the single-stick technique. Patient history, procedural records and clinical follow-up documents were retrospectively reviewed. Complication rates were compared to those of 41 patients receiving single-stick femoral central lines.

RESULTS

Technical complications occurred during one (3.0%) jugular placement with the patient having a failed right-side attempt with subsequent successful left-side placement. The catheters did not last the entire course of treatment in three (9.1%) patients with jugular lines. One patient had the catheter removed due to concern for infection, one catheter was accidentally removed during dressing changes, and one catheter was displaced and subsequently exchanged. Of patients receiving femoral central lines, 1 (2.4%) had a technical complication and 5 catheters (12.2%) did not last the entire course of treatment.

CONCLUSION

The placement of tunneled central venous catheters in neonates/infants <5 kg is safe and technically feasible using the internal/external jugular vein via the single-stick technique. By theoretically reducing the risks of catheter infection by avoiding the diaper area and thrombosis by using larger veins, it may be preferable in certain patient populations.

Stenosis Before Thrombosis: Intracranial Hypertension from Jugular Foramen Stenosis Secondary to Renal Osteodystrophy

BACKGROUND

Venous outflow obstructions are rare anatomic findings that can appear with symptoms of elevated intracranial pressure, including headache and vision loss, and can be mistaken for more common diagnoses, such as idiopathic intracranial hypertension (IIH) or cerebral venous sinus thrombosis (CVST). Although venous outflow obstructions have been reported in rare bone dysplasias and congenital abnormalities, to date they have not been reported in renal osteodystrophy (ROD), a relatively common disorder seen in patients with chronic kidney disease.

CASE DESCRIPTION

In this case, the authors describe a patient with marked intracranial hypertension from jugular foramen stenosis secondary to ROD. After diagnosis by CT and magnetic resonance venography, catheter venography confirmed an osseus band around the left jugular bulb, and a 40-mm Hg pressure gradient across the stenotic foramen. The patient subsequently underwent ventriculoperitoneal shunting and optic nerve sheath fenestration with symptom improvement. The postoperative course was significant for development of CVST, necessitating treatment.

CONCLUSIONS

This report reviews the presentation, pathology, and neurosurgical treatment of patients with ROD and venous outflow obstructions, and explores the differential diagnoses of outflow obstructions, IIH, and CVST. To our knowledge, this is the first report of intracranial hypertension from jugular foramen stenosis secondary to renal osteodystrophy.

One should avoid retro-orbital pharmacokinetic sample collections for intranasal dosing in rats: Illustration of spurious pharmacokinetics generated for anti-migraine drugs zolmitriptan and eletriptan

Because of the avoidance of first pass metabolic effects due to direct and rapid absorption with improved permeability, intranasal route represents a good alternative for extravascular drug administration. The aim of the study was to investigate the intranasal pharmacokinetics of two anti-migraine drugs (zolmitriptan and eletriptan), using retro-orbital sinus and jugular vein sites sampling. In a parallel study design, healthy male Sprague-Dawley (SD) rats aged between 8 and 12weeks were divided into groups (n=4 or 5/group). The animals of individual groups were dosed intranasal (~1.0mg/kg) and oral doses of 2.1mg/kg of either zolmitriptan or eletriptan. Serial blood sampling was performed from jugular vein or retro-orbital site and plasma samples were analyzed for drug concentrations using LC-MS/MS assay. Standard pharmacokinetics parameters such as T_max, C_max, AUC_last, AUC_0-inf and T_1/2 were calculated and statistics of derived parameters was performed using unpaired t-test. After intranasal dosing, the mean pharmacokinetic parameters C_max and AUC_inf of zolmitriptan/eletriptan showed about 17-fold and 3-5-fold higher values for retro-orbital sampling as compared to the jugular vein sampling site. Whereas after oral administration such parameters derived for both drugs were largely comparable between the two sampling sites and statistically non-significant. In conclusion, the assessment of plasma levels after intranasal administration with retro-orbital sampling would result in spurious and misleading pharmacokinetics.

Human jugular vein collapse in the upright posture: implications for postural intracranial pressure regulation

Background

Intracranial pressure (ICP) is directly related to cranial dural venous pressure (P_dural). In the upright posture, P_dural is affected by the collapse of the internal jugular veins (IJVs) but this regulation of the venous pressure has not been fully understood. A potential biomechanical description of this regulation involves a transmission of surrounding atmospheric pressure to the internal venous pressure of the collapsed IJVs. This can be accomplished if hydrostatic effects are cancelled by the viscous losses in these collapsed veins, resulting in specific IJV cross-sectional areas that can be predicted from flow velocity and vessel inclination.

Methods

We evaluated this potential mechanism in vivo by comparing predicted area to measured IJV area in healthy subjects. Seventeen healthy volunteers (age 45 ± 9 years) were examined using ultrasound to assess IJV area and flow velocity. Ultrasound measurements were performed in supine and sitting positions.

Results

IJV area was 94.5 mm² in supine and decreased to 6.5 ± 5.1 mm² in sitting position, which agreed with the predicted IJV area of 8.7 ± 5.2 mm² (equivalence limit ±5 mm², one-sided t tests, p = 0.03, 33 IJVs).

Conclusions

The agreement between predicted and measured IJV area in sitting supports the occurrence of a hydrostatic-viscous pressure balance in the IJVs, which would result in a constant pressure segment in these collapsed veins, corresponding to a zero transmural pressure. This balance could thus serve as the mechanism by which collapse of the IJVs regulates P_dural and consequently ICP in the upright posture.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-017-0065-2) contains supplementary material, which is available to authorized users.

Femoral indicator injection for transpulmonary thermodilution using the EV1000/VolumeView(®): do the same criteria apply as for the PiCCO(®)?

OBJECTIVE

Comparison of global end-diastolic volume index (GEDVI) obtained by femoral and jugular transpulmonary thermodilution (TPTD) indicator injections using the EV1000/VolumnView(®) device (Edwards Lifesciences, Irvine, USA).

METHODS

In an 87-year-old woman with hypovolemic shock and equipped with both jugular and femoral vein access and monitored with the EV1000/VolumeView(®) device, we recorded 10 datasets, each comprising duplicate TPTD via femoral access and duplicate TPTD (20 ml cold saline) via jugular access.

RESULTS

Mean femoral GEDVI ((674.6±52.3) ml/m(2)) was significantly higher than jugular GEDVI ((552.3±69.7) ml/m(2)), with P=0.003. Bland-Altman analysis demonstrated a bias of (+122±61) ml/m(2), limits of agreement of -16 and +260 ml/m(2), and a percentage error of 22%. Use of the correction-formula recently suggested for the PiCCO(®) device significantly reduced bias and percentage error. Similarly, mean values of parameters derived from GEDVI such as pulmonary vascular permeability index (PVPI; 1.244±0.101 vs. 1.522±0.139; P<0.001) and global ejection fraction (GEF; (24.7±1.6)% vs. (28.1±1.8)%; P<0.001) were significantly different in the case of femoral compared to jugular indicator injection. Furthermore, the mean cardiac index derived from femoral indicator injection ((4.50±0.36) L/(min·m²)) was significantly higher (P=0.02) than that derived from jugular indicator injection ((4.12±0.44) L/(min·m²)), resulting in a bias of (+0.38±0.37) L/(min·m²) and a percentage error of 19.4%.

CONCLUSIONS

Femoral access for indicator injection results in markedly altered values provided by the EV1000/VolumeView(®), particularly for GEDVI, PVPI, and GEF.

Cardiac, Respiratory and Postural Influences on Venous Return of Internal Jugular and Vertebral Veins

It is known from physiology that heartbeat and respiration influence venous return, but little is known regarding the extent to which these two factors affect flow. In this study, we estimated the prevalence of cardiac- and breathing-induced venous flow modulations in the internal jugular vein (IJV) and vertebral vein (VV) and the effects of posture. In 19 healthy patients, neck vein flow was examined with pulsed wave Doppler. Electrocardiogram and respiratory signals were simultaneously acquired. In supine position, heart contraction always influenced venous flow, whereas breathing influenced 68% of IJV and 34% of VV flow. In sitting position, heart contraction influenced 74% of IJV and 42% of VV flow; breathing influenced 68% of IJV and 61% of VV measures. Thus, cardiac influence is greatly present in supine position, whereas breathing influence prevails in the VV while sitting. This setup allowed us to observe that in some patients, expiration may cause an unexpected increase in venous flow.

External Jugular Vein Thrombosis as a Sign of Metastatic Breast Cancer

External jugular vein thrombosis is a rare vascular event which may lead fatal complication such as sepsis and pulmonary embolism. Its relation to the visceral solid tumor as an etiologic factor has been established well. Although external jugular vein thrombosis may be seen in malignancy, it is unusual to see as a sign of breast cancer. Most of the external jugular vein thrombosis occurs secondary to compression of the vein. Vascular thrombosis due to hypercoagulability is known as Trousseau syndrome. Herein, we present a case of metastatic breast cancer which presented with external jugular vein thrombosis; Trousseau syndrome.

Primary leiomyosarcoma of the jugular vein in a dog

A four-year-old, male, Labrador retriever was referred for removal of a spindle cell sarcoma involving the right jugular vein. A post-contrast CT scan showed a seven-centimeter subcutaneous mass originated from the right external jugular vein, which was partially obstructed and showing contrast stasis, suggested a primary intravascular tumor of the jugular vein. The mass was resected, and histological evaluation was consistent with grade II intravenous spindle cell sarcoma of the jugular vein. Immunohistochemical positivity for vimentin, desmin, and αSMA antibody and negativity for S-100 protein confirmed venous leiomyosarcoma. The dog received five doses of intravenous doxorubicin, and there was no recurrence of the tumor 30 months post treatment. In dogs, primary intravascular sarcomas are rare and primary venous leiomyosarcoma has not been described. A venous tumor may be considered as a differential diagnosis in dogs with ventral neck swelling.

Age differences in arterial and venous extra-cerebral blood flow in healthy adults: contributions of vascular risk factors and genetic variants

Sufficient cerebral blood flow (CBF) and venous drainage are critical for normal brain function, and their alterations can affect brain aging. However, to date, most studies focused on arterial CBF (inflow) with little attention paid to the age differences in venous outflow. We measured extra-cerebral arterial and venous blood flow rates with phase-contrast MRI and assessed the influence of vascular risk factors and genetic polymorphisms (ACE insertion/deletion, COMT val158met, and APOEε4) in 73 adults (age 18-74 years). Advanced age, elevated vascular risk, ACE Deletion, and COMT met alleles were linked to lower in- and outflow, with no effects of APOE ε4 noted. Lower age-related CBF rate was unrelated to brain volume and was observed only in val homozygotes of COMTval158met. Thus, in a disease-free population, age differences in CBF may be notable only in persons with high vascular risk and carriers of genetic variants associated with vasoconstriction and lower dopamine availability. It remains to be established if treatments targeting alleviation of the mutable factors can improve the course of cerebrovascular aging in spite of the immutable genetic influence.

The manifestation of vortical and secondary flow in the cerebral venous outflow tract: An in vivo MR velocimetry study

Aberrations in flow in the cerebral venous outflow tract (CVOT) have been implicated as the cause of several pathologic conditions including idiopathic intracranial hypertension (IIH), multiple sclerosis (MS), and pulsatile tinnitus (PT). The advent of 4D flow magnetic resonance imaging (4D-flow MRI) has recently allowed researchers to evaluate blood flow patterns in the arterial structures with great success. We utilized similar imaging techniques and found several distinct flow characteristics in the CVOT of subjects with and without lumenal irregularities. We present the flow patterns of 8 out of 38 subjects who have varying heights of the internal jugular bulb and varying lumenal irregularities including stenosis and diverticulum. In the internal jugular vein (IJV) with an elevated jugular bulb (JB), 4Dflow MRI revealed a characteristic spiral flow that was dependent on the level of JB elevation. Vortical flow was also observed in the diverticula of the venous sinuses and IJV. The diversity of flow complexity in the CVOT illustrates the potential importance of hemodynamic investigations in elucidating venous pathologies.

Single jugular vein cannulated rats may not be suitable for intravenous pharmacokinetic screening of high logP compounds

Rat is commonly used for pharmacokinetic screening during pharmaceutical lead optimization. To handle the large number of compounds, rats with a single jugular vein cannulation are commonly utilized for intravenous pharmacokinetic studies, where the same cannula is used both for dose administration and blood sampling. We demonstrate that the single cannula method is not suitable for all compounds, especially for high logP compounds. We propose an alternative dual cannulation technique in which two cannulas are placed in the same jugular vein, thus avoiding an additional surgery. Compounds were administered orally or via intravenous infusion to compare PK parameters, including bioavailability, using both procedures. For itraconazole and amiodarone, known to bind to the cannula, the measured plasma exposures were substantially higher in the single cannulated rats than those from dual cannulated rats. Area under the plasma concentration time curve differed by 79% and 74% for itraconazole and amiodarone, respectively. When compared to the single cannulation approach, clearance, volume of distribution and bioavailability determined by dual cannulation were 39%, 60% and 38% higher for itraconazole, and 46%, 34% and 42% higher for amiodarone, respectively. In contrast, all pharmacokinetic parameters were similar between single and dual-cannulated rats for the hydrophilic compound atenolol. Based on these results, we recommend the use of dual cannulated rats for intravenous pharmacokinetic studies when testing a series of hydrophobic compounds that may be prone to non-specific binding to the cannula. If single cannulated model is selected for pharmacokinetic screening, we recommend a bridging study with dual cannulated rats with representative compounds of a given chemical series.

Extra Luminal Entrapment of Guide Wire; A Rare Complication of Central Venous Catheter Placement in Right Internal Jugular Vein

Central venous Catheterization (CVC) is a commonly performed procedure for venous access. It is associated with several complications. We report a rare case of extra luminal entrapment of guide wire during CVC placement in right jugular vein. We report a case of 28 years old female patient presented in our emergency with history of entrapped guide wire in right side of neck during CVC. X-ray showed coiling of guide wire in neck. CT Angiography showed guide wire coursing in between common carotid artery and internal jugular vein (IJV), closely abutting the wall of both vessels. The guide wire was coiled with end coursing behind the esophageal wall. Guide wire was removed under fluoroscopic guide manipulation under local anesthesia. We want to emphasize that even though CVC placement is common and simple procedure, serious complication can occur in hands of untrained operator. The procedure should be performed under supervision, if done by trainee. Force should never be applied to advance the guide wire if resistance is encountered.

Encountering a high jugular bulb during ear surgery

Encounters with jugular bulb abnormalities during ear surgery are a rare but recognised problem. A high riding jugular bulb is present in 10%-15% of patients and its variable position within the temporal bone can lead to problems as brisk venous haemorrhage can result if the bulb is inadvertently opened. The case of a 52-year-old woman with a central tympanic membrane perforation who underwent elective endaural myringoplasty and experienced brisk bleeding on raising the tympanomeatal flap is presented.

Application and comparison of different implanted ports in malignant tumor patients

Background

The current study aims to compare the application and convenience of the upper arm port with the other two methods of implanted ports in the jugular vein and the subclavian vein in patients with gastrointestinal cancers.

Methods

Currently, the standard of practice is placement of central venous access via an internal jugular vein approach. Perioperative time, postoperative complications, and postoperative comfort level in patients receiving an implanted venous port in the upper arm were retrospectively compared to those in the jugular vein and the subclavian vein from April 2013 to November 2014.

Results

Three hundred thirty-four patients are recruited for this analysis, consisting of 107 in the upper arm vein group, 70 in the jugular vein group, and 167 in the subclavian vein group. The occurrence of catheter misplacement in the upper arm vein is higher than that in the other two groups (13.1 vs. 2.9 vs. 5.4 %, respectively, P = 0.02), while the other complications in the perioperative period were not significantly different. The occurrence of transfusion obstacle of the upper arm vein group is significantly lower than that of the jugular and subclavian groups (0.9 vs. 7.1 vs. 7.2 %, P = 0.01). The occurrence of thrombus is also lower than that of other two groups (0.9 vs. 4.3 vs. 3.6 %, P = 0.03). Regarding the postoperative comfort, the influences of appearance (0 vs. 7.1 vs. 2.9 %, P = 0.006) and sleep (0.9 vs. 4.2 vs. 10.7 %, P = 0.003) are significantly better than those of the jugular and subclavian vein groups.

Conclusions

Compared to the jugular and the subclavian vein groups, the implanted venous port in the upper arm vein has fewer complications and more convenience and comfort, and might be a superior novel choice for patients requiring long-term chemotherapy or parenteral nutrition.

Intravascular AAV9 Administration for Delivering RNA Silencing Constructs to the CNS and Periphery

Viral vector delivery of RNA silencing constructs, when administered into vasculature, typically results in poor central nervous system (CNS) transduction due to the inability of the vector to cross the blood-brain barrier (BBB). However, adeno-associated virus serotype 9 (AAV9) has the ability to cross the BBB and robustly transduce brain parenchyma and peripheral tissues at biologically meaningful levels when injected intravenously. Recent work by our lab has shown that this method can be used to deliver RNA silencing constructs, resulting in significant reductions in gene expression in multiple brain regions and in peripheral tissues. Here, we outline a method for delivery of AAV9 vectors expressing RNA interference (RNAi) constructs that lead to robust simultaneous transduction of mouse peripheral tissues and the CNS following a single injection into the jugular vein. Additionally, we outline methods for necropsy and immunofluorescence to detect AAV9 transduction patterns in the rodent CNS following a vascular delivery.

Extraordinary cerebral venous drainage pathway with mastoid emissary and posterior external jugular veins detected by contrast-enhanced neck computed tomography

An extraordinary cerebral venous drainage pathway and dilated vein at the left posterior cervical region were detected with routine contrast-enhanced neck computed tomography exam. The left sigmoid sinus was drained by dilated mastoid emissary vein (MEV). The MEV continued as posterior auricular and posterior external jugular veins (PEJVs). The left PEJV directly drained into subclavian vein. Atretic right transverse sinus, left facial vein forming the external jugular vein, atresia and hypoplasia of upper internal jugular veins at the right and left sides, respectively, were the other uncommon findings in our case. Detecting venous variations may prevent complications during surgical and interventional procedures, so the radiologists should examine the superficial cervical veins closely.

Histological changes of the unligated vein wall adjacent to the central venous catheter after open cutdown in rats

BACKGROUND

The sequelae of a central venous cutdown usually include venous deformity causing venous stenosis or stricture. However, the cellular mechanisms causing these deformities have not been elucidated.

METHODS

Silicone 2.7-Fr catheters were placed via the right external jugular vein of 16 rats with the cutdown method. After fixation with formalin at scheduled intervals (1week, 2weeks, 4weeks, and 8weeks; 4 rats in each group), the vein segment with the catheter in situ was harvested. Histological changes in the vein wall were studied and serially compared with light microscopy; standard hematoxylin-eosin staining, Masson's trichrome staining, van Gieson's elastin stain, and immunohistochemical stain against α-actin.

RESULTS

Pericatheter sleeve formation, circumferential smooth muscle cell proliferation and infiltration into the pericatheter sleeve by direct contact were noted in all 4 rats of 1-week model; this indicated the initiation of neointimal hyperplasia. The neointimal hyperplasia was located inside the elastin layer. At 2weeks, the SMCs stained faintly but the components of the vein wall were largely replaced by collagen. The proliferation and infiltration of SMCs stabilized at 4weeks and no SMCs were stained around the catheter. At 8weeks, luminal narrowing was noted and the venous wall was composed mainly of collagen.

CONCLUSIONS

Circumferential neointimal hyperplasia occurred after surgical cutdown of the external jugular vein in a rat model and was caused by SMC activation, proliferation, and infiltration into the pericatheter sleeve.