The jugular venous pressure revisited

Internal jugular vein collapsibility does not predict fluid responsiveness in spontaneously breathing patients after cardiac surgery

PURPOSE

The objective of our study was to evaluate the diagnostic accuracy of internal jugular vein (IJV) collapsibility as a predictor of fluid responsiveness in spontaneously breathing patients after cardiac surgery.

METHODS

In this prospective observational study, spontaneously breathing patients were enrolled on the first postoperative day after coronary artery bypass grafting. Hemodynamic data coupled with simultaneous ultrasound assessment of the IJV were collected at baseline and after passive leg raising test (PLR). Continuous cardiac index (CI), stroke volume (SV), and stroke volume variation (SVV) were assessed with FloTracTM/EV1000™. Fluid responsiveness was defined as an increase in CI ≥ 10% after PLR. We compared the differences in measured variables between fluid responders and non-responders and tested the ability of ultrasonographic IJV indices to predict fluid responsiveness.

RESULTS

Fifty-four patients were included in the study. Seventeen (31.5%) were fluid responders. The responders demonstrated significantly lower inspiratory and expiratory diameters of the IJV at baseline, but IJV collapsibility was comparable (P = 0.7). Using the cut-off point of 20%, IJV collapsibility predicted fluid responsiveness with a sensitivity of 76.5% and specificity of 38.9%, ROC AUC 0.55.

CONCLUSION

In spontaneously breathing patients after surgical coronary revascularisation, collapsibility of the internal jugular vein did not predict fluid responsiveness.

Cardiac tamponade

Cardiac tamponade is a medical emergency caused by the progressive accumulation of pericardial fluid (effusion), blood, pus or air in the pericardium, compressing the heart chambers and leading to haemodynamic compromise, circulatory shock, cardiac arrest and death. Pericardial diseases of any aetiology as well as complications of interventional and surgical procedures or chest trauma can cause cardiac tamponade. Tamponade can be precipitated in patients with pericardial effusion by dehydration or exposure to certain medications, particularly vasodilators or intravenous diuretics. Key clinical findings in patients with cardiac tamponade are hypotension, increased jugular venous pressure and distant heart sounds (Beck triad). Dyspnoea can progress to orthopnoea (with no rales on lung auscultation) accompanied by weakness, fatigue, tachycardia and oliguria. In tamponade caused by acute pericarditis, the patient can experience fever and typical chest pain increasing on inspiration and radiating to the trapezius ridge. Generally, cardiac tamponade is a clinical diagnosis that can be confirmed using various imaging modalities, principally echocardiography. Cardiac tamponade is preferably resolved by echocardiography-guided pericardiocentesis. In patients who have recently undergone cardiac surgery and in those with neoplastic infiltration, effusive-constrictive pericarditis, or loculated effusions, fluoroscopic guidance can increase the feasibility and safety of the procedure. Surgical management is indicated in patients with aortic dissection, chest trauma, bleeding or purulent infection that cannot be controlled percutaneously. After pericardiocentesis or pericardiotomy, NSAIDs and colchicine can be considered to prevent recurrence and effusive-constrictive pericarditis.

Method for measuring jugular venous pulse with a miniature gyroscope sensor patch

The right internal jugular vein is connected to the right atrium of the heart via the superior vena cava, and consequently its pressure, known as the jugular venous pressure or the jugular venous pulse (JVP), is an important indicator of cardiac function. The JVP can be estimated visually from the neck but it is rather difficult and imprecise. In this article we propose a method to measure the JVP using a motion sensor patch attached to the neck. The JVP signal was extracted from the sensor's 3-axes gyroscope signal and aligned with simultaneously measured ECG and seismocardiogram signals.The method was tested on 20 healthy subjects. The timings of the characteristic JVP waves were compared with the ECG R peaks and seismocardiogram heart sounds S1 and S2. The JVP was reliably measured from 18 subjects with all three waves identified. The timings of the waves were also physiologically plausible when compared to the ECG R peak and the heart sounds. Importantly, the JVP was also found to modulate with respiration, further indicating that the measured signal was indeed the JVP and not the carotid pulse.The results show that the JVP can be measured with a wearable patch-like device registering the delicate motions of the right internal jugular vein. The method has potential to be developed into a clinical tool to measure cardiac health in diseases such as heart failure and chronic obstructive pulmonary disease (COPD).Clinical relevance-The developed method could enable an affordable measurement of clinically important cardiac parameter, jugular venous pulse, as a part of a routine examination.

Jugular Venous Pulse Waveform Extraction From a Wearable Radio Frequency Sensor

Many prevalent heart diseases can be indicated by the features of the jugular venous pulse (JVP), an efficacious indicator of right heart health. However, JVP dynamics are not widely utilized in clinical settings as its observation and sensing remain cumbersome. Non-invasive measures of cardiac behavior, including the JVP, are of growing interest to enable continuous and at-home monitoring of cardiac disorders. In this work, we propose a wearable near-field radio-frequency (RF) sensor affixed with a neck collar on the clavicle over the internal jugular vein to enable non-invasive JVP sensing. We employed a complex vector injection signal processing method to extract repeatable JVP waveform features in multiple postures. With a 21-subject human study, we demonstrated morphologically consistent JVP sensing with consistent a-, c-, and v-wave feature timings, benchmarked by synchronous electrocardiogram and phonocardiogram. Further, inter-postural experiments demonstrated the capability of the proposed system to quantify morphological changes to the JVP which are present in many cardiac disorders. The results of this work suggest the proposed near-field RF sensor is capable of non-invasive JVP monitoring, potentially enabling improved sensing in both clinical and ambulatory environments.

A Novel Method for Estimating Right Atrial Pressure With Point-of-Care Ultrasound

BACKGROUND

Current noninvasive estimation of right atrial pressure (RAP) by either bedside jugular venous pressure exam or inferior vena cava measurement during a comprehensive echocardiogram offers imprecise estimates of actual RAP.

METHODS

We enrolled 41 patients in a prospective, blinded study to validate a novel point-of-care ultrasound method using direct right atrial depth (RAD) measurement and jugular venous ultrasound to estimate RAP. Two subjects were excluded, and 39 were included in the final analysis. A parasternal long-axis view was obtained, and the depth of the noncoronary cusp attachment to the posterior left ventricular outflow tract was recorded as the RAD. This was added to an estimate of the jugular venous pressure obtained during a jugular vein ultrasound to calculate an estimated RAP (RAP_US). The RAP_US was compared to the RAP measurement during right heart catheterization (RAP_cath) both as measured and as corrected for where the catheter was zeroed.

RESULTS

The correlation coefficient between RAP_cath and RAP_US was +0.75; regression R², 0.56; and bias, -0.49 mm Hg (95% CI, -1.42 to +0.43 mm Hg), with the limits of agreement -5.56 to +7.24 mm Hg and accuracy of 3 mm Hg or less in 29 (74%) of the subjects. For the RAP_US corrected for the catheter zero point, the correlation coefficient between RAP_cath and RAP_US was +0.72; regression R², 0.52; and bias, -0.60 mm Hg (95% CI, -1.60 to +0.39 mm Hg), with the limits of agreement -5.56 to +7.24 mm Hg and accuracy of 3 mm Hg or less in 26 (67%) of the subjects.

CONCLUSION

This simple ultrasound evaluation of RAD and the right jugular vein correlates well with actual RAP and can accurately estimate RAP within 3 mm Hg in most patients. This has the potential to improve our bedside volume status exam, as well as improve the accuracy of RAP estimation during comprehensive echocardiogram.

Central venous pressure estimation with force-coupled ultrasound of the internal jugular vein

We estimate central venous pressure (CVP) with force-coupled ultrasound imaging of the internal jugular vein (IJV). We acquire ultrasound images while measuring force applied over the IJV by the ultrasound probe imaging surface. We record collapse force, the force required to completely occlude the vein, in 27 healthy subjects. We find supine collapse force and jugular venous pulsation height (JVP), the clinical noninvasive standard, have a linear correlation coefficient of r² = 0.89 and an average absolute difference of 0.23 mmHg when estimating CVP. We perturb our estimate negatively by tilting 16 degrees above supine and observe decreases in collapse force for every subject which are predictable from our CVP estimates. We perturb venous pressure positively to values experienced in decompensated heart failure by having subjects perform the Valsalva maneuver while the IJV is being collapsed and observe an increase in collapse force for every subject. Finally, we derive a CVP waveform with an inverse three-dimensional finite element optimization that uses supine collapse force and segmented force-coupled ultrasound data at approximately constant force.

Pseudo-Kussmaul's Sign in Atrioventricular Nodal Reentry Tachycardia: A Prospective, Cohort Study

Aims

To study the respiratory variation of right atrial (RA) pressures at baseline and during atrioventricular nodal reentry tachycardia (AVNRT).

Methods

Of the 23 patients screened, 16 participants with typical AVNRT were included in the study. After ensuring adequate hydration, baseline RA pressures were measured as the height of 'a' and 'v' waves. The patients were asked to take deep breaths, and the measurements were taken in both inspiration and expiration.

Results

Of the 16 participants, 14(87.5%) showed a normal fall in the height of 'a' and 'v' waves with inspiration, 1(6.25%) showed no change and 1(6.25%) showed a rise in height at baseline, p <0.01. During induced AVNRT, the 'a' and 'v' wave heights increased in 8(50%), remained same in 6(37.5%) and showed a normal fall in 2(12.5%), p = 0.07 for 'a' waves and p = 0.09 for 'v' waves. When the magnitude and direction of change in 'a' and 'v' wave height at baseline was compared with AVNRT, it showed a significant difference with 13(81.25%) participants demonstrating positive Pseudo-Kussmaul's sign, p <0.01. Mean age was numerically higher in those with a more considerable inspiratory rise in RA pressures but was not statistically significant, χ²(2) = 3.1, p = 0.21.

Conclusions

Pseudo-Kussmaul's sign does occur in a substantial number of patients during AVNRT. Clinical appreciation of this phenomenon is possible in half to three-fourth of patients, provided the mean RA pressures are low enough for the variation to be visible in the neck.

The Identical External Reference Point Standardized to the Zero-Reference Level for Measuring Both Central and Jugular Venous Pressures: An Observational Study

Background

Studies report discrepancies between CVP and JVP measurements. The mid-thoracic plane (MTP) at the anterior fourth intercostal space level indicates the zero-reference level (ZRL) for venous pressure measurement, and the midaxillary line (MAL) at fourth intercostal space is a point near the ZRL in the supine position. JVP is usually measured from the sternal angle (SA) with further addition of 5 cm (JVP-SA + 5) and CVP in the supine position from MAL (CVP-MAL). However, no report has compared CVP measured from MTP (CVP-MTP) with CVP-MAL and with JVP from MTP (JVP-MTP) and JVP-SA + 5.

Methods

We measured JVP-MTP and JVP-SA + 5 in appropriate reclining positions and subsequently CVP-MTP and CVP-MAL in the supine position blindly in 150 patients. We compared the pressures by Pearson correlation and Bland-Altman plots.

Results

CVP-MTP and CVP-MAL demonstrated similar means (p = 0.129), strong positive linear relationship (r = 0.908), and good agreement (near-zero mean difference) with each other. JVP-MTP was about 1 cm higher than JVP-SA + 5 (p < 0.001). JVP-MTP displayed higher correlation coefficients and better agreements with both CVPs than JVP-SA+5. Correlation coefficients and mean differences of both CVPs with JVP-MTP were almost equal, about 0.83 and 1 cm, and with JVP-SA + 5 also almost equal, about 0.72 and 2 cm, respectively.

Conclusions

JVP tallies better with CVP examined in the supine position when both are measured from MTP as the identical external reference point (ERP), and MAL can be used as MTP to measure CVP in the supine position. Our findings indicate the way to explore the matching of CVP and JVP to the full extent possible by standardizing their measurements from other identical ERPs to that from the zero-reference level MTP. Their further study in similar higher reclining positions from identical ERPs, such as MTP, MAL, and SA with the addition of higher numbers instead of 5 cm, is warranted standardizing other measurements to that from MTP.

The Effect of Submaximal Exercise on Jugular Venous Pulse Assessed by a Wearable Cervical Plethysmography System

The jugular venous pulse (JVP) is a one of the crucial parameters of efficient cardiovascular function. Nowadays, limited data are available regarding the response of JVP to exercise because of its complex and/or invasive assessment procedure. The aim of the present work is to test the feasibility of a non-invasive JVP plethysmography system to monitor different submaximal exercise condition. Twenty (20) healthy subjects (13M/7F mean age 25 ± 3, BMI 21 ± 2) underwent cervical strain-gauge plethysmography, acquired synchronously with the electrocardiogram, while they were carrying out different activities: stand supine, upright, and during the execution of aerobic exercise (2 km walking test) and leg-press machine exercise (submaximal 6 RM test). Peaks a and x of the JVP waveform were investigated since they reflect the volume of cardiac filling. To this aim, the Δax parameter was introduced, representing the amplitude differences between a and x peaks. Significant differences in the values of a, x, and Δax were found between static and exercise conditions (p < 0.0001, p < 0.0001, p < 0.0001), respectively. Particularly, the Δax value for the leg press was approximately three times higher than the supine, and during walking was even nine times higher. The exercise monitoring by means of the novel JVP plethysmography system is feasible during submaximal exercise, and it provides additional parameters on cardiac filling and cerebral venous drainage to the widely used heartbeat rate value.

Worsening cardiac tamponade after pericardiocentesis in a patient with anterior mediastinum mass: a case report

Background

Mediastinal mass is an entity with variable pathology and clinical spectrum. Anterior mediastinal mass can result in severe symptoms due to involvement of surrounding vital structures such as the great vessels, trachea-bronchial tree, and heart. We highlight a case of cardiac tamponade in a patient with an anterior mediastinal mass that was paradoxically worsened after decompressive pericardiocentesis.

Case summary

A 21-year-old male presented to the emergency department (ED) with breathlessness and hypotension. Bedside focused cardiac ultrasound revealed cardiac tamponade which was made worse with an anterior mediastinal mass compressing the right heart chambers. The patient was intubated for respiratory failure, following which an ultrasound-guided pericardiocentesis was performed. Unexpectedly, his hemodynamic status worsened after aspiration of 1000 mL of pericardial fluid. A repeat focused cardiac ultrasound showed reduced pericardial effusion, but worsening of right heart chambers compression by the mediastinal mass. Re-expansion of the pericardium space with 600 mL of normal saline improved the patient’s vital signs, and reduced the right heart compression. Computed tomography was deferred due to the patient’s hemodynamic instability. Despite resuscitation with fluids and initiation of vasopressor, the patient’s condition deteriorated. He succumbed to his illness due to obstructive shock causing multi-organ failure. The autopsy showed a large anterior mediastinal mass, and histopathological examination confirmed the diagnosis of lymphoma.

Discussion

This case demonstrated the therapeutic challenges of managing a shock patient with anterior mediastinal mass, and massive pericardial effusion causing cardiac tamponade.

High Frame-Rate A-Mode Ultrasound System for Jugular Venous Pulse Tracking: A Feasibility Study

Jugular venous pulse (JVP) helps in the early detection of central venous pressure abnormalities and various cardiovascular diseases. Studies have been reported indicating that contour features of the JVP waveform provide crucial information regarding cardiac function. Although current ultrasound systems reliably provide the diameter measurements, they are limited by low frame rates resulting in poor resolution JVP cycles that are inadequate to yield distinguishable critical points. In this work, we propose an image-free high frame rate system for the assessment of JVP signals. The proposed A-mode ultrasound system acquires high fidelity JVP pulses with a temporal resolution of 4 ms and amplitude resolution of 10 µm. The functionality verification of the proposed system was performed by comparing it against a clinical-grade B-mode imaging system. A study was conducted on a cohort of 25 subjects in the 20-30 age group. While the system provided diameter measurements comparable to that of the imaging ones (r > 0.98, p < 0.05), it also yielded high-resolution JVP exhibiting the presence of all fiduciary points. This was a leveraging feature as opposed to the imaging system that possessed limited temporal and amplitude resolution. Clinical Relevance- The proposed system is a potential ultrasound means for measuring the diameter values from JV at the same time yielding the JVP critical points necessary for clinical analysis.

Congestive Heart Failure

Heart disease is the leading cause of death in the United States with an estimated 6 million adults living with heart failure. In patients with heart failure, the physical examination can provide important prognostic information and is also used to guide both diagnosis and management, including determining the need for inpatient versus outpatient management. Presenting symptoms include dyspnea, peripheral edema, orthopnea, paroxysmal nocturnal dyspnea, and bendopnea. In patients with suspected heart failure, a "head-to-toe" physical examination approach is recommended with the addition of special maneuvers such as the measurement of jugular venous pressure, valsalva maneuver, and hepatojugular reflux as needed.

Jugular Venous Pressure Response to Inspiration for Risk Assessment of Heart Failure

Simplifying jugular venous pressure (JVP), visibility of the right internal jugular vein above the right clavicle in the sitting position, has been proposed in the management of heart failure (HF) because of its convenience. However, this method may be undervalued for the detection of mildly to moderately increased JVP. Increased JVP on inspiration, known as Kussmaul sign, may be a useful physical finding in this condition. This study consisted of 138 patients who were admitted for the management of HF. Using this simple method, JVP was assessed at rest in the sitting position before discharge; its response to inspiration was also examined if no high JVP was noted at rest. The primary outcome was a composite of cardiac death and hospitalization for worsening HF. Among all the patients, 16 patients (12%) had high JVP at rest and another 16 patients (12%) had high JVP not at rest but on inspiration. During a follow-up period of 249 ± 182 days, a primary outcome event occurred in 63 patients (46%). The incidence of adverse cardiac events was higher in patients with a high JVP at rest (69%; hazard ratio 3.31, 95% confidence interval 1.64 to 6.67, p = 0.0009) and in patients with a high JVP on inspiration (56%; hazard ratio 2.18, 95% confidence interval 1.02 to 4.63, p = 0.043) than in patients without a high JVP in both conditions (41%). In conclusion, a high JVP not only at rest but also on inspiration was associated with a poor prognosis. The response of JVP to inspiration using this simple technique of physical examination may be a new approach in the management of HF.

The Sheep as a Comprehensive Animal Model to Investigate Interdependent Physiological Pressure Propagation and Multiparameter Influence on Cerebrospinal Fluid Dynamics

The present study aims to develop a suitable animal model for evaluating the physiological interactions between cerebrospinal fluid (CSF) dynamics, hemodynamics, and abdominal compartment pressures. We seek to contribute to the enhanced recognition of the pathophysiology of CSF-dependent neurological disorders like hydrocephalus and the improvement of available treatment options. To date, no comprehensive animal model of CSF dynamics exists, and establishing an accurate model will advance our understanding of complex CSF physiology. Persisting knowledge gaps surrounding the communication and pressure propagation between the cerebrospinal space and adjacent anatomical compartments exacerbate the development of novel therapies for neurological diseases. Hence, the need for further investigation of the interactions of vascular, craniospinal, and abdominal pressures remains beyond dispute. Moreover, the results of this animal study support the optimization of in vitro test benches for medical device development, e.g., ventriculoperitoneal shunts. Six female white alpine sheep were surgically equipped with pressure sensors to investigate the physiological values of intracranial, intrathecal, arterial, central venous, jugular venous, vesical pressure, and four differently located abdominal pressures. These values were measured simultaneously during the acute animal trial with sheep under general anesthesia. Both carotid and femoral arterial blood pressure indicate a reliable and comparable representation of the systematic blood pressure. However, the jugular venous pressure and the central venous pressure in sheep in dorsal recumbency do not correlate well under general anesthesia. Furthermore, there is a trend for possible comparability of lateral intraventricular and lumbar intrathecal pressure. Nevertheless, animal body position during measurements must be considered since different body constitutions can alter the horizontal line between the cerebral ventricles and the lumbar subarachnoid space. While intra-abdominal pressure measurement in the four different abdominal quadrants yielded greater inter-individual variability, intra-vesical pressure measurements in our setting delivered comparable values for all sheep. We established a novel and comprehensive ovine animal model to investigate interdependent physiologic pressure propagation and multiparameter influences on CSF dynamics. The results of this study will contribute to further in vitro bench testing, the derivation of novel quantitative models, and the development of a pathologic ovine hydrocephalus model.

Comparison of clinical symptoms and bioimpedance to pulmonary capillary wedge pressure in heart failure

Introduction

Clinical symptoms of heart failure commonly include fatigue, edema, and shortness of breath. Unfortunately, clinical monitoring has proven unreliable in predicting congestion and the need for hospitalization. Biosensing wearables have been developed as a potential adjunct to clinical signs and symptoms to detect congestion before it becomes severe thus preventing a heart failure hospitalization.

Hypothesis

Clinical signs and symptoms of heart failure will correlate with thoracic bioimpedance measurements (ZOE®) and pulmonary capillary wedge pressure (PCWP).

Methods

One hundred and fifty-five subjects undergoing right heart catheterization (RHC) were prospectively enrolled. A Zo value (ohms) was obtained, jugular venous pressure (JVP) was estimated, edema graded, and shortness of breath (SOB) assessed in all subjects. RHC was performed by a scheduled cardiologist per routine. One-way ANOVA was performed to assess the relationship between variables. A Pearson correlation coefficient was used to compare the Zo value and PCWP.

Results

Neither estimated JVP (cmH2O) (p = 0.65, n = 110) nor edema scores (p = 0.12, n = 110) demonstrated a significant relationship to PCWP. The presence of subjective SOB also did not demonstrate a significant association with PCWP (p = 0.99, n = 110). There was no correlation between ZOE® and PCWP (r = -0.08, p = 0.56, n = 56).

Conclusions

These findings support the idea that traditional measures for monitoring heart failure patients are limited.

Palpitations: Evaluation and management by primary care practitioners

Palpitations are a common, non-specific presenting complaint in primary healthcare and emergency departments. Palpitations are mostly a symptom of benign underlying disease but a sign of life-threatening conditions. Importantly, palpitations are a symptom and not a diagnosis, and cardiac causes are the most concerning aetiology. Clinicians should seek to identify the underlying cause. History and physical examination are important in the assessment of patients with palpitations, and the use of a 12-lead electrographic (ECG) monitor on presentation is the gold standard of diagnosis. If the aetiology cannot be determined, an ambulatory Holter 24–48-h monitor can be used. Treatment and follow-up of patients presenting with palpitations as the main complaint will depend on the aetiology and investigation findings. Patients with palpitations accompanied by dizziness, excessive fatigue, or chest pains should receive adequate acute care aiming to stabilise their condition before referring to a higher level of care.

Sex-dependent jugular vein optical attenuation and distension during head-down tilt and lower body negative pressure

Non‐contact coded hemodynamic imaging (CHI) is a novel wide‐field near‐infrared spectroscopy system which monitors blood volume by quantifying attenuation of light passing through the underlying vessels. This study tested the hypothesis that CHI‐based jugular venous attenuation (JVA) would be larger in men, and change in JVA would be greater in men compared to women during two fluid shift challenges. The association of JVA with ultrasound‐based cross‐sectional area (CSA) was also tested. Ten men and 10 women completed three levels of head‐down tilt (HDT) and four levels of lower body negative pressure (LBNP). Both JVA and CSA were increased by HDT and reduced by LBNP (all p < 0.001). Main effects of sex indicated that JVA was higher in men than women during both HDT (p = 0.003) and LBNP (p = 0.011). Interaction effects of sex and condition were observed for JVA during HDT (p = 0.005) and LBNP (p < 0.001). We observed moderate repeated‐measures correlations (r_rm) between JVA and CSA in women during HDT (r_rm = 0.57, p = 0.011) and in both men (r_rm = 0.74, p < 0.001) and women (r_rm = 0.66, p < 0.001) during LBNP. While median within‐person correlation coefficients indicated an even stronger association between JVA and CSA, this association became unreliable for small changes in CSA. As hypothesized, JVA was greater and changed more in men compared to women during both HDT and LBNP. CHI provides a non‐contact method of tracking large changes in internal jugular vein blood volume that occur with acute fluid shifts, but data should be interpreted in a sex‐dependent manner.

Hemodynamic pathways of gestational hypertension and preeclampsia

Gestational hypertension and preeclampsia are the 2 main types of hypertensive disorders in pregnancy. Noninvasive maternal cardiovascular function assessment, which helps obtain information from all the components of circulation, has shown that venous hemodynamic dysfunction is a feature of preeclampsia but not of gestational hypertension. Venous congestion is a known cause of organ dysfunction, but its potential role in the pathophysiology of preeclampsia is currently poorly investigated. Body water volume expansion occurs in both gestational hypertension and preeclampsia, and this is associated with the common feature of new-onset hypertension after 20 weeks of gestation. Blood pressure, by definition, is the product of intravascular volume load and vascular resistance (Ohm's law). Fundamentally, hypertension may present as a spectrum of cardiovascular states varying between 2 extremes: one with a predominance of raised cardiac output and the other with a predominance of increased total peripheral resistance. In clinical practice, however, this bipolar nature of hypertension is rarely considered, despite the important implications for screening, prevention, management, and monitoring of disease. This review summarizes the evidence of type-specific hemodynamic profiles in the latent and clinical stages of hypertensive disorders in pregnancy. Gestational volume expansion superimposed on an early gestational closed circulatory circuit in a pressure- or volume-overloaded condition predisposes a patient to the gradual deterioration of overall circulatory function, finally presenting as gestational hypertension or preeclampsia-the latter when venous dysfunction is involved. The eventual phenotype of hypertensive disorder is already predictable from early gestation onward, on the condition of including information from all the major components of circulation into the maternal cardiovascular assessment: the heart, central and peripheral arteries, conductive and capacitance veins, and body water content. The relevance of this approach, outlined in this review, openly invites for more in-depth research into the fundamental hemodynamics of gestational hypertensive disorders, not only from the perspective of the physiologist or the scientist, but also in assistance of clinicians toward understanding and managing effectively these severe complications of pregnancy.

Integrative Volume Status Assessment

Volume status assessment is a critical but challenging clinical skill and is especially important for the management of patients in the emergency department, intensive care unit, and dialysis unit where accurate intravascular assessment is necessary to guide appropriate fluid management. Assessment of volume status is subjective and can vary from provider to provider, posing clinical dilemmas. Traditional non-invasive methods of volume assessment include assessment of skin turgor, axillary sweat, peripheral edema, pulmonary crackles, orthostatic vital signs, and jugular venous distension. Invasive assessments of volume status include direct measurement of central venous pressure and pulmonary artery pressures. Each of these has their own limitations, challenges, and pitfalls and were often validated based on small cohorts with questionable comparators. In the past 30 years, the increased availability, progressive miniaturization, and falling price of ultrasound devices has made point of care ultrasound (POCUS) widely available. Emerging evidence base and increased uptake across multiple subspecialities has facilitated the adoption of this technology. POCUS is now widely available, relatively inexpensive, free of ionizing radiation, and can help providers make medical decisions with more precision. POCUS is not intended to replace the physical exam, but rather to complement clinical assessment, guiding providers to give thorough and accurate clinical care to their patients. We should be mindful of the nascent literature supporting the use of POCUS and other limitations as uptake increases among providers and be wary not to use POCUS to substitute clinical judgement, but integrate ultrasonographic findings carefully with history and clinical examination.

Plethysmography System to Monitor the Jugular Venous Pulse: A Feasibility Study

Cerebral venous outflow is investigated in the diagnosis of heart failure through the monitoring of jugular venous pulse, an indicator to assess cardiovascular diseases. The jugular venous pulse is a weak signal stemming from the lying internal jugular vein and often invasive methodologies requiring surgery are mandatory to detect it. Jugular venous pulse can also be extrapolated via the ultrasound technique, but it requires a qualified healthcare operator to perform the examination. In this work, a wireless, user-friendly, wearable device for plethysmography is developed to investigate the possibility of monitoring the jugular venous pulse non-invasively. The proposed device can monitor the jugular venous pulse and the electrocardiogram synchronously. To study the feasibility of using the proposed device to detect physiological variables, several measurements were carried out on healthy subjects by considering three different postures: supine, sitting, and upright. Data acquired in the experiment were properly filtered to highlight the cardiac oscillation and remove the breathing contribution, which causes a considerable shift in the amplitude of signals. To evaluate the proper functioning of the wearable device for plethysmography, a comparison with the ultrasound technique was carried out. As a satisfactory result, the acquired signals resemble the typical jugular venous pulse waveforms found in literature.

Ultrasound-Guided Preload Indices during Different Weaning Protocols of Mechanically Ventilated Patients and its Impact on Weaning Induced Cardiac Dysfunction

BACKGROUND: Elevation of the left ventricular (LV) filling pressure can occur during weaning of mechanical ventilation due to increase in LV preload and/or changes in LV compliance and LV afterload. AIM: The aim of the study was to evaluate respiratory changes in internal jugular vein and inferior vena cava during weaning from mechanical ventilation. METHODS: Prospective observational study conducted on 80 consecutive patients. Patients were divided randomly into two groups who met the readiness criteria to start spontaneous breathing trial (SBT) either on pressure support ventilation (PS/CPAP) for 30 min or T-piece for 120 min. Weaning failure was defined as a failed SBT or reintubation within 48 h. Echocardiographic evaluation was done on assisted controlled ventilation and at the end of SBT for preload assessment. RESULTS: Mitral Septal E/E’ Cutoff value ≥6.1 with sensitivity 81% and specificity 84.2%, and AUC 0.73 for predicting weaning failure. IVC distensibility index on CPAP cutoff value ≥66.5% with sensitivity 100% and specificity 68.4%, and AUC 0.85. In Group II, Mitral Septal E/E’ Cut off value ≥5.8 with sensitivity 83% and specificity 90.9%, AUC 0.83, IVC collapsibility index Cut off value ≥45.5% with sensitivity 72% and specificity 86%, AUC 0.73. CONCLUSION: Mitral Septal E/E’ could predict weaning-induced diastolic dysfunction. IVC plays an important role in predicting weaning failure.

Spectral characteristics of the internal jugular vein and central venous pressure pulses: a proof of concept study

In this proof-of-concept study the impact of central venous pressure (CVP) on internal jugular veins cross-sectional area (CSA) and blood flow time-average velocity (TAV) was evaluated in eight subjects, with the aim of understanding the drivers of the jugular venous pulse. CVP was measured using a central venous catheter while CSA variation and TAV along a cardiac cycle were acquired using ultrasound. Analysis of CVP, CSA and TAV time-series signals revealed TAV and CSA to lag behind CVP by on average 0.129 s and 0.138 s, with an inverse correlation between CSA and TAV (r= –0.316). The respective autocorrelation signals were strongly correlated (mean r=0.729-0.764), with mean CSA periodicity being 1.062 Hz. Fourier analysis revealed the frequency spectrums of CVP, TAV and CSA signals to be dominated by frequencies at approximately 1 and 2 Hz, with those >1 Hz greatly attenuated in the CSA signal. Because the autocorrelograms and periodograms of the respective signals were aligned and dominated by the same underlying frequencies, this suggested that they are more easily interpreted in the frequency domain rather than the time domain.

Does this patient have jugular venous distension? Vein finder-enhanced assessment of jugular venous pressure

Assessing jugular venous pressure (JVP) may be challenging yet useful for establishing the bedside diagnosis of congestive heart failure. Vein finder lights illuminate superficial veins and thus can improve visualization of the external jugular vein.

Bioinspired Gradient Conductivity and Stiffness for Ultrasensitive Electronic Skins

Hierarchical and gradient structures in biological systems with special mechanical properties have inspired innovations in materials design for construction and mechanical applications. Analogous to the control of stress transfer in gradient mechanical structures, the control of electron transfer in gradient electrical structures should enable the development of high-performance electronics. This paper demonstrates a high performance electronic skin (e-skin) via the simultaneous control of tactile stress transfer to an active sensing area and the corresponding electrical current through the gradient structures. The flexible e-skin sensor has extraordinarily high piezoresistive sensitivity at low power and linearity over a broad pressure range based on the conductivity-gradient multilayer on the stiffness-gradient interlocked microdome geometry. While stiffness-gradient interlocked microdome structures allow the efficient transfer and localization of applied stress to the sensing area, the multilayered structure with gradient conductivity enables the efficient regulation of piezoresistance in response to applied pressure by gradual activation of current pathways from outer to inner layers, resulting in a pressure sensitivity of 3.8 × 10⁵ kPa^-1 with linear response over a wide range of up to 100 kPa. In addition, the sensor indicated a rapid response time of 0.016 ms, a low minimum detectable pressure level of 0.025 Pa, a low operating voltage (100 μV), and high durability during 8000 repetitive cycles of pressure application (80 kPa). The high performance of the e-skin sensor enables acoustic wave detection, differentiation of gas characterized by different densities, subtle tactile manipulation of objects, and real-time monitoring of pulse pressure waveform.

Central venous pressure estimation from ultrasound assessment of the jugular venous pulse

Objectives

Acquiring central venous pressure (CVP), an important clinical parameter, requires an invasive procedure, which poses risk to patients. The aim of the study was to develop a non-invasive methodology for determining mean-CVP from ultrasound assessment of the jugular venous pulse.

Methods

In thirty-four adult patients (age = 60 ± 12 years; 10 males), CVP was measured using a central venous catheter, with internal jugular vein (IJV) cross-sectional area (CSA) variation along the cardiac beat acquired using ultrasound. The resultant CVP and IJV-CSA signals were synchronized with electrocardiogram (ECG) signals acquired from the patients. Autocorrelation signals were derived from the IJV-CSA signals using algorithms in R (open-source statistical software). The correlation r-values for successive lag intervals were extracted and used to build a linear regression model in which mean-CVP was the response variable and the lagging autocorrelation r-values and mean IJV-CSA, were the predictor variables. The optimum model was identified using the minimum AIC value and validated using 10-fold cross-validation.

Results

While the CVP and IJV-CSA signals were poorly correlated (mean r = -0.018, SD = 0.357) due to the IJV-CSA signal lagging behind the CVP signal, their autocorrelation counterparts were highly positively correlated (mean r = 0.725, SD = 0.215). Using the lagging autocorrelation r-values as predictors, mean-CVP was predicted with reasonable accuracy (r² = 0.612), with a mean-absolute-error of 1.455 cmH₂O, which rose to 2.436 cmH₂O when cross-validation was performed.

Conclusions

Mean-CVP can be estimated non-invasively by using the lagged autocorrelation r-values of the IJV-CSA signal. This new methodology may have considerable potential as a clinical monitoring and diagnostic tool.

Response of Jugular Venous Pressure to Exercise in Patients With Heart Failure and Its Prognostic Usefulness

Jugular venous pressure (JVP) has been established for the assessment of central venous pressure in patients with heart failure (HF), but data are limited regarding the response of JVP to exercise because of its complicated methods. Simplifying the estimation of JVP may be applied in such situations. JVP was assessed before and after the 6-minute walk test (6MWT) in 81 patients with HF using a simple method by which the JVP was considered high when the internal jugular venous pulsation on the right side was visually identified above the right clavicle in the sitting position. The primary outcome was a composite of cardiovascular death and hospitalization for worsening HF. None of the patients exhibited high JVP before the 6MWT and 11 patients (14%) had a high JVP after. The 6MWT distances were lower in patients with a high JVP after the 6MWT (338 ± 114 m) than those in patients without a high JVP (417 ± 78 m, p = 0.04). During a follow-up period of 13.4 ± 6.9 months, 11 patients died and 8 patients were hospitalized for worsening HF. The incidence of adverse cardiac events was higher in patients with a high JVP after the 6MWT (64%) than in patients without a high JVP after (64% vs 17%; hazard ratio, 7.52; 95% confidence interval, 2.69 to 20.83; p <0.001). In conclusion, high JVP after exercise was associated with exercise intolerance and poor prognosis. The response of JVP to exercise using this simple technique of physical examination may be a new approach for patients with HF for risk assessment.

Back to Basics: Key Physical Examinations and Theories in Patients with Heart Failure

Heart failure (HF) is a leading cause of hospitalization. Suitable pharmacologic management is critical. Distinct physical findings such as congestion and peripheral hypoperfusion need to be considered in selecting pharmacologic therapy. By applying the pretest probability and likelihood ratios of unique physical findings of HF to a Markov model, a definite posttest probability can be obtained. This article focuses on the findings of S3, jugular venous pressure, proportional pulse pressure, bendopnea, trepopnea, and various heart murmurs. Incorporating statistical precision in physical assessments, diagnoses of HF can be further refined, providing a sophisticated approach to evaluate patients hemodynamics status noninvasively.

Non-surgical Risk Factors for the Development of Chylothorax in Children after Cardiac Surgery-Does Fluid Matter?

We hypothesize that there are post-operative, non-surgical risk factors that could be modified to prevent the occurrence of chylothorax, and we seek to determine those factors. Retrospective chart review of 285 consecutive patients < 18 years who underwent cardiac surgery from 2015 to 2017 at a single institution pediatric intensive care unit. Data was collected on patient demographics, cardiac lesion, surgical and post-operative characteristics. Primary outcome was development of chylothorax. Of 285 patients, median age was 189 days, median weight was 6.6 kg, 48% were female, and 10% had trisomy 21. 3.5% of patients developed upper extremity DVTs, and 8% developed chylothorax. At 24 h following surgery, a majority were in the 0-10% fluid overload category or had a negative fluid balance (63% and 34%, respectively), and a positive fluid balance was rare at 72 h (16%). In univariate analysis, age, weight, bypass time, DVT, arrhythmia, and trisomy 21 were significantly associated with chylothorax and adjusted for in logistic regression. Presence of an upper extremity DVT (OR 49.8, p < 0.001) and trisomy 21 (OR 5.8, p < 0.001) remained associated with chylothorax on regression modeling. The presence of an upper extremity DVT and trisomy 21 were associated with the development of chylothorax. Fluid overload was rare in our population. The presence of positive fluid balance, fluid overload, elevated central venous pressure, and early initiation of fat containing feeds were not associated with chylothorax.

The practical management of fluid retention in adults with right heart failure due to pulmonary arterial hypertension

Our aim with this review is to provide practical advice and management support for nurses and other healthcare practitioners in managing fluid retention in adults with right heart failure (RHF) due to pulmonary arterial hypertension (PAH). Vigilant management of RHF is important for maintaining patient quality of life, as fluid overload can lead to abdominal bloating (ascites) and peripheral oedema, which also has a major impact on patients' morbidity and mortality. Patients with RHF should be assessed regularly for signs of fluid retention. If fluid overload develops, it is important to determine whether it is caused by the progression of PAH, a side effect of PAH-specific treatment, or another drug or comorbid condition, as this affects both the prognosis and the management strategy. Right heart failure can be treated with both pharmacological and non-pharmacological interventions to reduce fluid retention; including altering fluid and salt intake, weight monitoring, and use of diuretics. All patients on diuretics should be regularly monitored for renal dysfunction and electrolyte imbalance and given advice on how to manage the side effects associated with diuretic use. Fluid retention is often assessed and treated in clinical practice by specialist nurses, who act as a key patient contact providing advice and information on symptom management. This review provides an overview of the challenges related to fluid retention, including strategies to help patients manage symptoms and side effects of treatment.

Non-contact Quantification of Jugular Venous Pulse Waveforms from Skin Displacements

The jugular venous (JV) pressure waveform is a non-invasive, proven indicator of cardiovascular disease. Conventional clinical methods for assessing these waveforms are often overlooked because they require specialised expertise, and are invasive and expensive to implement. Recently, image-based methods have been used to quantify JV pulsation waveforms on the skin as an indirect way of estimating the pressure waveforms. However, these existing image-based methods cannot explicitly measure skin deformations and rely on the use of photoplethysmography (PPG) devices for identification of the pulsatile waveforms. As a result, they often have limited accuracy and robustness and are unsuitable in the clinical environment. Here, we propose a technique to directly measure skin deformations caused by the JV pulse using a very accurate subpixel registration algorithm. The method simply requires images obtained from the subject’s neck using a commodity camera. The results show that our measured waveforms contained all of the essential features of diagnostic JV waveforms in all of 19 healthy subjects tested in this study, indicating a significantly important capability for a potential future diagnostic device. The shape of our measured JV displacement waveforms was validated using waveforms measured with a laser displacement sensor, where the average correlation score between the two waveforms was 0.93 ± 0.05. In addition, synchronously recorded ECG signals were used to verify the timings of diagnostic features of the measured waveforms. To our knowledge, this is the first use of image registration for direct measurement of JV displacement waveforms. Significant advantages of our novel method include the high precision of our measurements, and the ability to use ordinary cameras, such as those in modern mobile phones. These advantages will enable the development of affordable and accessible devices to measure JV waveforms for cardiac diagnostics in the clinical environment. Future devices based on this technology may provide viable options for telemedicine applications, point of care diagnostics, and mobile-based cardiac health monitoring systems.

Internal jugular vein variability predicts fluid responsiveness in cardiac surgical patients with mechanical ventilation

BACKGROUND

To evaluate the efficacy of using internal jugular vein variability (IJVV) as an index of fluid responsiveness in mechanically ventilated patients after cardiac surgery.

METHODS

Seventy patients were assessed after cardiac surgery. Hemodynamic data coupled with ultrasound evaluation of IJVV and inferior vena cava variability (IVCV) were collected and calculated at baseline, after a passive leg raising (PLR) test and after a 500-ml fluid challenge. Patients were divided into volume responders (increase in stroke volume ≥ 15%) and non-responders (increase in stroke volume < 15%). We compared the differences in measured variables between responders and non-responders and tested the ability of the indices to predict fluid responsiveness.

RESULTS

Thirty-five (50%) patients were fluid responders. Responders presented higher IJVV, IVCV and stroke volume variation (SVV) compared with non-responders at baseline (P < 0.05). The relationship between IJVV and SVV was moderately correlated (r = 0.51, P < 0.01). The areas under the receiver operating characteristic (ROC) curves for predicting fluid responsiveness were 0.88 (CI 0.78-0.94) for IJVV compared with 0.83 (CI 0.72-0.91), 0.97 (CI 0.89-0.99), 0.91 (CI 0.82-0.97) for IVCV, SVV, and the increase in stroke volume in response to a PLR test, respectively.

CONCLUSIONS

Ultrasound-derived IJVV is an accurate, easily acquired noninvasive parameter of fluid responsiveness in mechanically ventilated postoperative cardiac surgery patients, with a performance similar to that of IVCV.

Flexible Sensing Electronics for Wearable/Attachable Health Monitoring

Wearable or attachable health monitoring smart systems are considered to be the next generation of personal portable devices for remote medicine practices. Smart flexible sensing electronics are components crucial in endowing health monitoring systems with the capability of real-time tracking of physiological signals. These signals are closely associated with body conditions, such as heart rate, wrist pulse, body temperature, blood/intraocular pressure and blood/sweat bio-information. Monitoring such physiological signals provides a convenient and non-invasive way for disease diagnoses and health assessments. This Review summarizes the recent progress of flexible sensing electronics for their use in wearable/attachable health monitoring systems. Meanwhile, we present an overview of different materials and configurations for flexible sensors, including piezo-resistive, piezo-electrical, capacitive, and field effect transistor based devices, and analyze the working principles in monitoring physiological signals. In addition, the future perspectives of wearable healthcare systems and the technical demands on their commercialization are briefly discussed.

Complications from carcinoid syndrome: review of the current evidence

Patients with well-differentiated neuroendocrine tumours may develop carcinoid syndrome (CS), which is characterised by flushing, abdominal cramps, diarrhoea, and bronchospasms. In this scenario, long-term secretion of vasoactive substances—serotonin, tachynins, and others, may induce fibrogenic responses in local or distant tissues, leading to complications such as carcinoid heart disease (CHD), mesenteric and/or retroperitoneal fibrosis. Rare cases of lung/pleural fibrosis and scleroderma have also been described. Despite it not being well described yet, current evidence suggests the pathogenesis of such fibrogenic complications relies on signalling through 5-HT_2B and TGF-β1. Medical management is still very limited and lacks prospective and randomised studies for definitive recommendations. Surgical procedures remain the best definitive treatment option for CHD and abdominal fibrosis. Recently, cognitive impairment has also been described as a potential consequence of CS. This review critically discusses the literature concerning the epidemiology, pathogenesis, clinical features, diagnosis, and treatment options for CS-related long-term complications.

Cardiac Variation of Internal Jugular Vein for the Evaluation of Hemodynamics

Evaluations of intravascular fluid volume are considered to be one of the most important assessments in emergency and intensive care. Focusing on pulse-induced variation of the internal jugular vein (IJV) area, i.e., cardiac variation, we investigated its correlation with various hemodynamic indices using newly developed software. Software that automatically can track and analyze the IJV during ultrasonography was developed. Eleven healthy patients were subjected to an exercise load to increase their stroke volume (SV) and a dehydration load to decrease their central venous pressure (CVP). The cardiac variation in the area of the IJV, CVP, the SV and the respiratory variation in the inferior vena cava (IVC) were evaluated. The exercise protocol increased the patients' mean SV by 14.5 ± 3.7 mL, and the dehydration protocol caused their mean CVP to fall by 3.75 ± 0.33 cm H2O, which resulted in the collapse index (max IJV area - min IJV area/max IJV area) changing from 0.32 ± 0.04 to 0.44 ± 0.06 and 0.49 ± 0.04, respectively (p < 0.05). The SV exhibited a strong positive correlation with the collapse index (r = 0.59, p = 0.006), and CVP showed a strong positive correlation with the body height-adjusted mean area of the IJV (r = 0.72, p < 0.001). Cardiac variation in the area of the great veins is considered to be induced by venous return to the right atrium under negative pressure. It is possible that intravascular dehydration can be detected and hemodynamic indices, such as CVP and SV, can be estimated by evaluating cardiac variation in the area of the IJV.

Clinical Applicability of Assessment of Jugular Flow over the Individual Cardiac Cycle Compared with Current Ultrasound Methodology

There is growing interest in measuring cerebral venous outflow with ultrasound (US). However, results obtained with the current US Doppler methodology, which uses just a single value of cross-sectional area (CSA) of the vessel, are highly variable and inconclusive. The product of CSA and time-averaged velocity in the case of pulsatile vessels may be a possible source of error, particularly for a pulsatile vein like the internal jugular vein (IJV), where the cardiac pump transmits a sequence of well-established waves along the conduit. We herein propose a novel technique for US IJV flow assessment that accurately accounts for IJV CSA variations during the cardiac cycle. Five subjects were investigated with a high-resolution real-time B-mode video, synchronized with an electrocardiography trace. In this approach, CSA variations representing the pulsatility of the IJV are overlapped with the velocity curve obtained by the usual spectral Doppler trace. The overlap is then phased point by point using the electrocardiography pacemaker. This allows us to experimentally measure the velocity variation in relation to the change in CSA precisely, ultimately enabling calculation of IJV flow. (i) The sequence of CSA variation with respect to the electrocardiography waves corresponds exactly to the jugular venous pulse as measured in physiology. (ii) The methodology permits us to phase the velocity and CSA, which is ultimately what is currently lacking to precisely calculate the flow in the IJV with US. (iii) The time-averaged flow, calculated with the described technique, is very close to that calculated assuming a constant IJV CSA, whereas the time-dependent flow shows differs as much as 40%. (iv) Finally, we tested the accuracy of the technique with a methodology that may allow for universal assessment of the accuracy of each personal US-based evaluation of flow rate.

Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

The Oscillating Component of the Internal Jugular Vein Flow: The Overlooked Element of Cerebral Circulation

The jugular venous pulse (JVP) provides valuable information about cardiac haemodynamics and filling pressures and is an indirect estimate of the central venous pressure (CVP). Recently it has been proven that JVP can be obtained by measuring the cross-sectional area (CSA) of the IJV on each sonogram of an ultrasound B-mode sonogram sequence. It has also been proven that during its pulsation the IJV is distended and hence that the pressure gradient drives the IJV haemodynamics. If this is true, then it will imply the following: (i) the blood velocity in the IJV is a periodic function of the time with period equal to the cardiac period and (ii) the instantaneous blood velocity is given by a time function that can be derived from a flow-dynamics theory that uses the instantaneous pressure gradient as a parameter. The aim of the present study is to confirm the hypothesis that JVP regulates the IJV blood flow and that pressure waves are transmitted from the heart toward the brain through the IJV wall.

An ultrasonographic technique to assess the jugular venous pulse: a proof of concept

The purpose of the work described here was to investigate the feasibility of assessing the jugular venous pulse (JVP) using ultrasound (US) equipment. Three young healthy subjects underwent a B-mode US scan of the internal jugular vein (IJV) to acquire a sonogram sequence in the transverse plane. On each acquired sonogram, the IJV contour was manually traced, and both the cross-sectional area (CSA) and the perimeter were measured. The CSA data set represents the US jugular diagram (USJD). The arterial distension waveform of the subjects was compared with its USJD. The correlation between the CSA and the perimeter was assessed during the cardiac cycle to verify IJV distension. For each subject, a short sonogram sequence of a few seconds was recorded, and the USJD obtained exhibited periodic behavior. Furthermore, for all subjects, the CSA was found to be correlated with the perimeter (Pearson coefficient, R > 0.9), indicating that the IJV in supine position is distended. We compared 390 manually traced contours of the IJV cross-sectional area with corresponding values semi-automatically calculated by an algorithm developed in-house. For all subjects, the sensitivity, specificity and accuracy were around 95%, 85% and 90% respectively. We found that a diagram reflecting the JVP can be obtained by analyzing a B-mode sonogram sequence of the IJV; such a diagram can result in a new methodology to assess the IJV functionality.

Highly skin-conformal microhairy sensor for pulse signal amplification

A bioinspired microhairy sensor is developed to enable ultraconformability on nonflat surfaces and significant enhancement in the signal-to-noise ratio of the retrieved signals. The device shows ≈12 times increase in the signal-to-noise ratio in the generated capacitive signals, allowing the ultraconformal microhair pressure sensors to be capable of measuring weak pulsations of internal jugular venous pulses stemming from a human neck.

Jugular vein distensibility predicts fluid responsiveness in septic patients

INTRODUCTION

The purpose of the study was to verify the efficacy of using internal jugular vein (IJV) size and distensibility as a reliable index of fluid responsiveness in mechanically ventilated patients with sepsis.

METHODS

Hemodynamic data of mechanically ventilated patients with sepsis were collected through a radial arterial indwelling catheter connected to continuous hemodynamic monitoring system (Most Care®, Vytech Health, Padova, Italy), including cardiac index (CI) (L/min/M(2)), heart rate (beats/min), mean arterial pressure (MAP) (mmHg), central venous pressure (CVP) (mmHg) and arterial pulse pressure variation (PPV), coupled with ultrasound evaluation of IJV distensibility (%), defined as a ratio of the difference between IJV maximal antero-posterior diameter during inspiration and minimum expiratory diameter to minimum expiratory diameter x100. Patients were retrospectively divided into two groups; fluid responders (R), if CI increase of more than or equal to 15% after a 7 ml/kg crystalloid infusion, and non-responders (NR) if CI increased more than 15%. We compared differences in measured variables between R and NR groups and calculated receiver-operator-characteristic (ROC) curves of optimal IJV distensibility and PPV sensitivity and specificity to predicting R. We also calculated a combined inferior vena cava distensibility-PPV ROC curve to predict R.

RESULTS

We enrolled 50 patients, of these, 30 were R. Responders presented higher IJV distensibility and PPV before fluid challenge than NR (P <0.05). An IJV distensibility more than 18% prior to volume challenge had an 80% sensitivity and 85% specificity to predict R. Pairwise comparison between IJV distensibility and PPV ROC curves revealed similar ROC area under the curve results. Interestingly, combining IJV distensibility more than 9.7% and PPV more than 12% predicted fluid responsiveness with a sensitivity of 100% and specificity of 95%.

CONCLUSION

IJV distensibility is an accurate, easily acquired non-invasive parameter of fluid responsiveness in mechanically ventilated septic patients with performance similar to PPV. The combined use of IJV distensibility with left-sided indexes of fluid responsiveness improves their predictive value.

An argument for using additional bedside tools, such as bedside ultrasound, for volume status assessment in hospitalized medical patients: a needs assessment survey

The frequency at which housestaff need to assess volume status on medical inpatients is unknown. In this brief report, we invited 39 housestaff, over 13 randomly selected dates, to complete a 25-item survey. Participants (n = 31, 79%) logged a total of 455 hours, reporting 197 pages or telephone requests received regarding medical inpatients. Of these, 41 pages (21%) required a volume status assessment. Participants reported their volume status assessment competency to be moderate (median score = 3, interquartile range = 3 to 4, where 1 = not competent to perform independently and 6 = above average competence). In 9 of the 41 assessments (22%), at least 1 barrier was reported in determining volume status. The most commonly reported barriers were conflicting physical examination findings (n = 8, 20%) and suboptimal patient examination (n = 5, 12%). Over 20% of pages regarding admitted medical patients required volume status assessments by medical housestaff. Despite moderate self-reported competence in the ability to assess volume status, barriers such as conflicting physical examination findings and suboptimal patient examinations were present in up to 20% of assessments. Therefore, we urge educators to consider incorporating bedside ultrasound training for volume status into the internal medicine curriculum.

Non-invasive bedside assessment of central venous pressure: scanning into the future

BACKGROUND

Noninvasive evaluation of central venous pressure (CVP) can be achieved by assessing the Jugular Venous Pressure (JVP), Peripheral Venous Collapse (PVC), and ultrasound visualization of the inferior vena cava. The relative accuracy of these techniques compared to one another and their application by trainees of varying experience remains uncertain. We compare the application and utility of the JVP, PVC, and handheld Mini Echo amongst trainees of varying experience including a medical student, internal medicine resident, and cardiology fellow. We also introduce and validate a new physical exam technique to assess central venous pressures, the Anthem sign.

METHODS

Patients presenting for their regularly scheduled echocardiograms at the hospital echo department had clinical evaluations of their CVP using these non-invasive bedside techniques. The examiners were blinded to the echo results, each other's assessments, and patient history; their CVP estimates were compared to the gold standard level 3 echo-cardiographer's estimates at the completion of the study.

RESULTS

325 patients combined were examined (mean age 65, s.d. 16 years). When compared to the gold standard of central venous pressure by a level 3 echocardiographer, the JVP was the most sensitive at 86%, improving with clinical experience (p<0.01). The classic PVC technique and Anthem sign had better specificity compared to the JVP. Mini Echo estimates were comparable to physical exam assessments.

CONCLUSIONS

JVP evaluation is the most sensitive physical examination technique in CVP assessments. The PVC techniques along with the newly described Anthem sign may be of value for the early learner who still has not mastered the art of JVP assessment and in obese patients in whom JVP evaluation is problematic. Mini Echo estimates of CVPs are comparable to physical examination by trained clinicians and require less instruction. The use of Mini Echo in medical training should be further evaluated and encouraged.