Conventional echo color Doppler versus ULA-OP in the assessment of venous flow model

The quantification of venous flows can be obtained by multiplying cross sectional area, measured on a B-mode video-clip, by velocity values, obtained with Doppler measurements. The Doppler angle between ultrasound (US) line and blood flow requires a manual adjustment. Establishing this parameter is critical in order to calculate blood velocity. However, the operator dependency gives high variable results. It is worth noting that a new class of vector Doppler devices can enhance the accuracy and precision of measurements. Such technology uses a double US line that leads to automatically know the Doppler angle. By comparing in an in vitro model of venous flow conventional echo color Doppler (ECD) equipment with the new device, we found a better minimal difference between the latter and the nominal flow rate (20%). On the contrary, the comparison with conventional ECD showed a difference ranging between 2% and 43%, according to the possible settings of the equipment. Our study demonstrates a better accuracy of the experimental device with respect to conventional ECD in measuring the venous flow rate

Study of internal jugular vein valve mechanism function: post analysis of M- mode imaging and an experimental model under cardiac monitoring.

Background: Traditionally, the internal jugular vein (IJV) has served as an indicator of right side cardiac function via measurement of central venous pressure and changes in the velocity of jugular venous flow. Since the internal jugular vein valve is the only protective vessel between the brain and heart, recent studies have focused on the dynamic behavior of the valve and its importance in regulating the cerebral blood out flow pathway. It is found that the function of the IJV valve is crucial in maintaining the transcranial blood pressure gradient during cardiopulmonary resuscitation with closed-chest while the morphological incompetence (or absence) of the valve may lead to venous reflux through the IJV. However, nothing is known about the mechanism of the valve opening and closure, as well as the normal opening time. Furthermore, there is insufficient knowledge whether the venous reflux is a normal finding and it is not associated with valve incompetence or valve absence. Aim of the study: The project aims to add new indicators of internal Jugular valve function through: 1) post imaging analysis using ultrasound M mode image and 2) an experimental model of mimicking fluid loop to study the modality of flow and pressure wave, upstream and downstream in internal jugular vein with or without valve build up. Methods: Normal young subjects underwent an ultrasound scan of the neck in supine position. The internal jugular vein valve was evaluated using B-mode and M-mode images. Two methods have been demonstrated to deduce the normal open time of the valve. The first method based on calculating the area under the curve of valve leaflet separation distance ratio per cardiac cycle. The second method is based on logical tests of three thresholds to examine the valve leaflet separation distance ratio. A hydraulic mimicking fluid loop is created using a programmable pump (Compu Flow 1000, Shelley Medical Imaging/London/Canada). The flow-loop model represents the cerebral out flow pathway through internal Jugular phantoms with and without valve build up. The measurements of flow and pressure were taking at two positions upstream and downstream of the phantom. Results: The first method concerning the normal open time reveals a strong positive correlation with second method at the threshold 0.5. The open time of IJV valve constitutes 70% of the cardiac cycle. The experimental model yields a different modality of flow and pressure upstream and downstream of phantoms. A back flow occurs in the beginning of the pulsatile flow wave at a downstream position. The difference in pressure between the two positions increases with the mean flow rate and decreases with higher flow rate in the phantom with no valve while in phantom with valve, the pressure difference has mostly linear proportion with the flow rate. Conclusions: The normal open time of the internal jugular vein valve is a new physiologic metric and it gives premise for further studies in the field of neurodegeneration. The experimental finding is adding a new concept to the venous reflux in the internal jugular vein and the necessity of the valve presence in maintain an adequate pressure difference through IJV.Introduzione: Lo studio emodinamico della vena giugulare interna (IJV) fornisce indicazioni sulla funzionalità cardiaca. La vena giugulare interna è dotata di una valvola che ha una funzione protettiva, studi recenti si sono concentrati sul comportamento dinamico della valvola e sulla sua importanza nella regolazione del flusso ematico cerebrale. Questi studi hanno mostrato che questa valvola ha la funzione di regolare il gradiente della pressione nell’asse cervello – cuore. L’assenza o l'incompetenza funzionale della valvola può anche portare al fenomeno del reflusso venoso attraverso la IJV. Tuttavia, il meccanismo dell'apertura e della chiusura della valvola non è stato ancora studiato a fondo, in particolare non sono si hanno informazioni sul suo ritmo di apertura e chiusura. Inoltre, non vi sono conoscenze sufficienti per capire se il fenomeno del reflusso venoso sia normale o possa essere associato a incompetenza della valvola e quindi indicatore di possibili stati patologici. Obiettivo dello studio: Il progetto mira ad individuare nuovi indicatori della funzione della valvola giugulare interna attraverso: 1) Studio delle immagini ecografiche della valvola acquisite in M mode; 2) Utilizzo di circuito fluidodinamico sperimentale per lo studio della relazione tra impulso pressorio a monte e a valle della vena giugulare ed il suo flusso in presenza ed assenza della valvola interna. Metodi: Un gruppo soggetti normali sono stati sottoposti ad ecografia del collo in posizione supina. La valvola vena giugulare interna è stata studiata usando le immagini acquisite sia B-mode che M-mode. Sono stati utilizzati due metodi per ricavare informazioni sui tempi di apertura e di chiusura della valvola. Il primo metodo è basato sul calcolo dell'area sottesa dalla curva che rappresenta la distanza di separazione del lembo della valvola per un intero ciclo cardiaco. Il secondo metodo vuole introdurre test logici utilizzando tre soglie di riferimento per studiare la distanza di separazione delle alette della valvola. E’ stato realizzato un circuito idraulico che imita la fluidodinamica del tratto Ventricolo – Cervello – Atrio utilizzando una pompa programmabile (Compu Flow 1000, Shelley Medical Imaging / London / Canada) che immette un fluido in un circuito ad anello avente segmenti che possono simulare la vena Giugulare con e senza valvola Risultati: Il primo metodo di studio del tempo apertura ha una buona correlazione positiva con metodo logico quando si utilizza il parametro di soglia soglia 0,5. Il tempo di apertura della valvola IJV è circa il 70% della durata di ogni ciclo cardiaco. Il modello sperimentale fornisce risultati specifici per le due diverse misure di flusso e pressione (a monte e a valle) dei fantocci. Il fenomeno del reflusso si verifica all'inizio dell'onda di flusso pulsatile in una posizione a valle per il flussi più alti. La differenza di pressione tra le due posizioni aumenta con la portata media e diminuisce crescere della portata nel fantoccio senza valvola mentre nell’altro (con valvola), la differenza di pressione ha un andamento lineare con la portata. Conclusioni: Il tempo di apertura della valvola vena giugulare interna rappresenta una nuova metrica fisiologica che può essere utilizzata per ulteriori studi più approfonditi nel campo della insufficienze del ritorno venoso cerebrale. Il modello sperimentale ha aggiunto di un nuove informazioni sulla comparsa del al reflusso venoso nei simulatori della vena giugulare interna e sulla funzione della della valvola nel mantenere un'adeguata gradiente pressorio nella IJV

Cerebral venous drainage through internal jugular vein

Internal jugular veins (IJVs) are the largest veins in the neck and are considered the primary cerebral venous drain for the intracranial blood in supine position. Any reduction in their flow could potentially results an increase in cerebral blood volume and intracranial pressure (ICP). The right internal jugular vein communicates with the right atrium via the superior vena cava, in which a functional valve is located at the union of the internal jugular vein and the superior vena cava. The atrium aspiration is the main mechanism governing the rhythmic leaflets movement of internal jugular vein valve synchronizing with the cardiac cycle. Cardiac contractions and intrathoracic pressure changes are reflecting in Doppler spectrum of the internal jugular vein. The evaluation of the jugular venous pulse provides valuable information about cardiac hemodynamics and cardiac filling pressures. The normal jugular venous pulse wave consists of three positive waves, a, c, and v, and two negative waves, x and y. A normal jugular vein gradually reduces its longitudinal diameter, as described in anatomy books; it is possible to segment IJV into three different segments J3 to J1, as it proposed in ultrasound US studies and CT scan. In this review, the morphology and methodology of the cerebral venous drainage through IJV are presented

Knowledge of Saudi parents toward the emergency management of avulsed permanent teeth: A cross-sectional survey

Introduction: Traumatic dentoalveolar injuries are frequent in children, affecting teeth, their supporting structures, and adjacent soft tissues. Parents are among the first people to deal with tooth avulsion among children at home or at play. This study, therefore, aimed to examine parental knowledge and attitudes about avulsed permanent teeth and their emergency treatment in children. Materials and Methods: A cross-sectional study was carried out with 274 parents of children receiving care at KKU College of Dentistry, Abha. Informed consent was obtained after explaining the nature of the study and data were collected using a self-administered questionnaire. Data were entered in MS Excel Sheet, and descriptive statistics were obtained. Results: Sixty-one percent of the parents reported dental trauma at home or school. 67.2% were not aware of the steps to be taken in tooth avulsion. The percentage for the source of information for avulsed tooth was a dentist (38.8%) and the internet (34.5%). 73.8% were unaware of the fact that permanent avulsed tooth can be replanted. 56.3% parents said that they would discard the knocked out tooth. Regarding knowledge about traumatic dental injuries 43.9% said it is imperative to know about it. Conclusion: This survey reflected the lack of awareness and adequate knowledge regarding the avulsed tooth. There is an imperative need for educating the parents regarding management of avulsed tooth permanent tooth

Mechanical Function of Internal Jugular Vein Valve: Post-analysis of M-Mode Imaging under Cardiac Monitoring

Because the internal jugular vein (IJV) valve is the only protective valve between the brain and heart, recent studies have focused on the dynamic behaviour of the valve and its importance in regulating the cerebral blood outflow pathway. However, the mechanism underlying valve opening and closure, as well as the normal opening time, has not been investigated before. The aim of the study described here was to investigate IJV physiology in healthy young adults by means of ultrasound imaging. Twenty-four normal young adults (16 male, 8 female, 21.79 ± 0.79 y of age) were enrolled in this study. Each participant underwent IJV B- and M-mode ultrasound scans of the neck veins in supine position. Data on IJV leaflet movement and IJV blood velocity were extracted from images with the associated electrocardiogram traces to analyze the opening and closure cycles of IJV leaflets. The normal opening time calculated in this study includes 70% of the dynamic valve cycle. The normal opening time of the IJV valve could be a new physiologic metric and serves as a premise for further studies in the field of cerebral venous return

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population