Vein Collapse Research Articles

Diagnostic accuracy of subclavian vein versus inferior vena cava collapsibility index for predicting postinduction hypotension: An observational study

Background: Hypotension following induction of general anesthesia (GA) is commonly observed. Ultrasound (US) measurement of collapsibility index (CI) of the inferior vena cava (IVC) for predicting postinduction hypotension has been studied. As there is limited data available comparing the diagnostic accuracy of subclavian vein (SCV) versus IVC-CI, we performed this observational study. Methods: A total of 132 adult patients scheduled for elective surgery under GA were enrolled. US measurements of three readings of maximum and minimum diameters of SCV and IVC were recorded during both quiet and deep breathing, and the mean of three values was calculated. CI was derived using the formula: (dmax – dmin) × 100/dmax. Subsequently, GA was administered using standard technique, irrespective of the findings of SCV and IVC measurements. The administered drugs and dosage were recorded. Hemodynamic parameters were collected at baseline and then at every minute for the first 20 min. The primary objective was to compare the diagnostic accuracies of SCV-CI and IVC-CI for prediction of postinduction hypotension during quiet breathing. The secondary objectives were to compare the diagnostic accuracies during deep breathing and find the correlation between IVC-CI and SC-CI during quiet and deep breathing, incidence of hypotension, and time required to acquire US images. Results: Fifty-seven patients developed postinduction hypotension. During quiet breathing, SCV-CI ≥10% had a sensitivity of 68% and specificity of 56% (area under curve [AUC] [95% confidence interval {CI}] of 0.659 [0.56–0.75]; P = 0.002), while IVC-CI ≥34% had a sensitivity of 70% and specificity of 59% (AUC [95% CI] of 0.672 [0.58–0.76]; P = 0.001) for prediction of postinduction hypotension. During deep breathing, both SCV-CI and IVC-CI had moderate accuracy (P = 0.001 for both). Pearson’s correlation showed a significant positive correlation between SCV-CI and IVC-CI with a correlation coefficient (r) of 0.313 during quiet breathing and 0.379 during deep breathing (P < 0.001). The time required for acquiring US images was significantly less for SCV compared to IVC during both quiet and deep breathing (P < 0.001 for both). Conclusion: Both SCV-CI and IVC-CI were found to have good and comparable diagnostic accuracy for the prediction of postinduction hypotension. We also found a significant positive correlation between SCV-CI and IVC-CI. In comparison to IVC, US scanning of SCV took lesser time to acquire the images.

Internal Jugular Vein Collapsibility Index versus Inferior Vena Cava Collapsibility Index Guided Preloading for Prevention of Spinal Anesthesia Induced Hypotension During LSCS: An Interventional Study

Background and Aims: Goal directed fluid therapy (GDFT) in parturients helps to prevent spinal anesthesia induced hypotension (SAIH) and volume overload. This interventional study compared the inferior vena cava collapsibility index (IVCCI) and the internal jugular vein collapsibility index (IJVCI) guided preloading for prevention of SAIH during lower segment ceserean section (LSCS) in terms of the incidence of SAIH as the primary outcome and the total amount of fluid, mean dose of the vasopressor, the number of boluses of vasopressor required, and the incidence of intra-operative complications as secondary outcomes. Methodology: A total of 144 full-term parturients aged 20–40 years with American society of anaesthesiologists (ASA) grade II, height (140–165 cms), weight (40–70 kgs), those who were fluid responders, and those who had a window period of 1 hour before surgery under spinal anesthesia (SA) undergoing LSCS were allocated into two groups (n = 72): group IJV and group IVC. Ultrasonography (USG) guided Internal jugular vein (IJV) and Inferior vena cava (IVC) collapsibility index (CI) was recorded an hour before spinal anesthesia (SA) as per the groups assigned and preloaded accordingly. After SA, the incidence of SAIH, the requirement of vasopressor, and fluid were recorded, and side effects were managed. Results: In group IVC, the incidence of SAIH (36.84%), mean dose (3.51 ± 5.02 µg), and mean boluses (0.44 ± 0.63) of norepinephrine required to manage hypotension were significantly lower than in group IJV, and the mean goal directed fluid administered before LSCS (504.46 ± 181.48 ml) and overall mean total fluid (1104.39 ± 160.99 ml) administered were significantly higher than in group IJV. Except for shivering, the incidence of all other complications was significantly lower in group IVC (p < 0.05). Conclusion: Both IVCCI and IJVCI guided preloading are effective in combating SAIH during LSCS, but IVCCI is comparatively better than IJVCI for CI guided preloading.

Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study.

Prompt assessments and quick replacement of intravascular fluid are critical steps to resuscitate hypovolemic patients. Intravascular volume assessment by direct central venous pressure (CVP) measurement is an invasive, time-consuming, and labor-intensive procedure. Nowadays, bedside ultrasound-guided volume assessment of the internal jugular vein (IJV) or inferior vena cava (IVC) is commonly employed as a proxy for direct CVP.Therefore, we examined the strength of association between CVP and collapsibility index (CI) of the IJV and IVC for evaluating the volume status of critically ill patients. Bedside USG-guided A-P diameter and cross-sectional area of the right IJV and IVC were measured, and their corresponding collapsibility indices were deduced. The results of the IJV and IVC indices were correlated with CVP. About 60 out of 70 enrolled patients were analyzed. The baseline clinical parameters of patients are shown in Table 1. For CSA and AP diameter, the correlations between CVP and IJV-CI at 0° were r = -0.107 (p = 0.001) and r = -0.092 (p = 0.001). Correlations between CVP and IJV-CI at 30° for CSA and diameter, however, were (r = -0.109, p = 0.001) and (r = -0.117, p = 0.001), respectively. Table 2 depicts the correlation between CVP and IVC-CI r = -0.503, p = 0.001 for CSA and r = -0.452, p = 0.001 for diameter. The IVC and IJV collapsibility indices can be used in place of invasive CVP monitoring to assess fluid status in critically ill patients. Kumar A, Bharti AK, Hussain M, Kumar S, Kumar A. Correlation of Internal Jugular Vein and Inferior Vena Cava Collapsibility Index with Direct Central Venous Pressure Measurement in Critically-ill Patients: An Observational Study. Indian J Crit Care Med 2024;28(6):595-600.

Association of infraclavicular axillary vein diameter and collapsibility index with general anesthesia-induced hypotension in elderly patients undergoing gastrointestinal surgery: an observational study

BackgroundThe collapse index of inferior Vena Cava (IVC) and its diameter are important predictive tools for fluid responsiveness in patients, especially critically ones. The collapsibility of infraclavicular axillary vein (AXV) can be used as an alternative to the collapsibility of IVC (IVC-CI) to assess the patient’s blood volume.MethodsA total of 188 elderly patients aged between 65 and 85 years were recruited for gastrointestinal surgery under general anesthesia. Ultrasound measurements AXV and IVC were performed before induction of general anesthesia. Patients were grouped in accordance to the hypotension after induction. ROC curves were used to analyze the predictive value of ultrasound measurements of AXV and IVC for hypotension after induction of anesthesia. Pearson linear correlation was used to assess the correlation of ultrasound measurements and decrease in mean arterial blood pressure (MAP).ResultsThe maximum diameter of AXV(dAXVmax) and the maximum diameter of IVC (dIVCmax) were not related to the percentage decrease in MAP; the collapsibility of AXV (AXV-CI) and IVC-CI were positively correlated with MAP changes (correlation coefficients:0.475, 0.577, respectively, p < 0.001). The areas under the curve (AUC) was 0.824 (0.759–0.889) for AXV-CI, and 0.874 (0.820–0.928) for IVC-CI. The optimal threshold for AXV-CI was 31.25% (sensitivity 71.7%, specificity 90.1%), while for IVC-CI was 36.60% (sensitivity 85.9%, specificity 79.0%). Hypotension and down-regulation of MAP during induction can be accurately predicted by AXV-Cl after correction for confounding variables.ConclusionInfraclavicular axillary vein diameter has no significant correlation with postanesthesia hypotension, whereas AXV-CI may predict postanesthesia hypotension during gastrointestinal surgery of the elderly.Trial registrationThis study was registered in the Clinical Trial Registry of China on 05/06/2022 (ChiCTR2200060596).

Subclavian Vein Collapsibility as a Predictor of Fluid Responsiveness in Spontaneously Breathing Hypotensive Patients

Background and Objective: Volume replacement remains the cornerstone of resuscitation in critically ill patients. This study explored the ability of the subclavian vein collapsibility index to predict fluid responsiveness. Methods: In this prospective observational study conducted in the Department of Medicine, All India Institute of Medical Sciences (AIIMS), New Delhi, sonographic evaluation of inferior vena cava and the right subclavian vein was carried out at three time points for hypotensive patients admitted to the emergency department. The study population was divided into two groups: responders and non-responders, based on a ≥ 15 % increase in stroke volume following fluid bolus. Results: Among 45 recruited patients, 33 patients were responders. The area under the ROC curve for SCV CI at baseline to predict fluid responsiveness was 0.745 (95% confidence interval: 0.549 – 0.941; p = 0.014). An SCV-CI of 46 % predicted fluid responsiveness in a hypotensive patient in terms of change in stroke volume by 15% following fluid bolus with a sensitivity of 87.88 % (95 % confidence interval: 71.80% to 96.60%) and specificity of 66.67 % (95 % confidence interval: 34.89% to 90.08%). Spearman’s correlation coefficient between IVC CI and SCV CI was 0.59 (p &lt; 0.001, n = 135). Conclusion: The results of the study demonstrated that right subclavian vein respiratory variation has the ability to predict fluid responsiveness in a spontaneously breathing patient in circulatory shock and correlates with the inferior vena cava collapsibility index. The subclavian vein can be an alternative to the inferior vena cava in predicting fluid responsiveness in spontaneously breathing patients.

Evaluation of the Effect of Three Different Tidal Volumes on Internal Jugular Vein Collapsibility Index in Hypovolemic Mechanically-Ventilated Patients Before and After Fluid Therapy

Evaluation of the Effect of Three Different Tidal Volumes on Internal Jugular Vein Collapsibility Index in Hypovolemic Mechanically-Ventilated Patients Before and After Fluid Therapy

Correlation of Internal Jugular Vein Collapsibility With Central Venous Pressure in Patients With Liver Cirrhosis.

We aimed to compare internal jugular vein and inferior vena cava ultrasonography as predictors of central venous pressure in cirrhotic patients. We performed ultrasound assessments of the internal jugular vein (IJV) and the inferior vena cava and then invasively measured central venous pressure (CVP). We then compared their correlation with CVP and performed area under the receiver operating characteristic curves to determine which had best sensitivity and specificity. IJV cross-sectional area collapsibility index at 30° correlated better with CVP ( r = -0.56, P < 0.001), and an IJV AP-CI at 30° ≤ 24.8% was better at predicting a CVP ≥8 mm Hg, with 100% sensitivity and 97.1% specificity. Thus, IJV point-of-care ultrasound might be superior than inferior vena cava point-of-care ultrasound as a predictor of CVP in cirrhotic patients.

Prediction of Hypotension During Neuraxial Anesthesia in Patients with Pregnancy-Induced Hypertension Through Subclavian Vein Collapsibility Index

Objective: To explore and evaluate the predictive value of subclavian vein collapsibility index (SCV-CI) on hypotension during neuraxial anesthesia in patients with pregnancy-induced hypertension (PIH). Methods: Pregnant women with PIH who underwent elective cesarean section in our hospital from January to July 2021 were selected as the research subjects. Patients who experienced hypotension during anesthesia were included into the hypotension group, whereas patients who had a normal blood pressure during anesthesia were included in the normotensive group. The SCV-CI was then calculated for three respiratory cycles, the average value was taken as the base value, and the patient was monitored for another 20 minutes. The blood pressure, heart rate, blood oxygen saturation, and SCV-CI of the patients were measured, and the incidence of maternal nausea and vomiting and cord blood gas were recorded. Then, a correlation analysis was conducted on the relationship between subclavian vein collapsibility index and hypotension. A receiver operating characteristic curve was drawn to seek the threshold value of subclavian vein collapsibility index for post-anesthesia hypotension. Results: There was no significant difference in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) between the two groups before anesthesia (P &gt; 0.05). After anesthesia, the above indexes (SBP, 103.25 ± 12.48 mmHg; DBP, 58.94 ± 7.46 mmHg; and HR, 52.96 ± 6.48 beats/min) were significantly lower than those of the normal blood pressure group, and the difference was statistically significant (P &lt; 0.05). In comparison, the SCV-CI in the hypotension group was 35.82 ± 4.93% greater than that in the normal blood pressure group (23.85 ± 5.27%), and the incidence of nausea and vomiting in the hypotension group (40.0%) was significantly higher than that in the normotensive group (10.53%), and the difference was statistically significant (P &lt; 0.05). The area under the curve of SCV-CI prediction against hypotension in patients with PIH under neuraxial anesthesia was 0.825 (95% CI: 0.762–0.893, P &lt; 0.001), the cut-off value was 25.68%, the predictive sensitivity was 92.68%, and the specificity was 81.24%. Conclusion: SCV-CI has a good predictive value for the occurrence of hypotension in patients with PIH during neuraxial anesthesia.

Role of Internal Jugular Vein Collapsibility Index in Predicting Post-spinal Hypotension in Pregnant Women Undergoing Cesarean Section: A Prospective Observational Study.

Introduction Post-spinal hypotension (PSH) frequently occurs in women undergoing cesarean section. In recent studies, Ultrasound-guided measurements of the internal jugular vein (IJV) have been reported to predict fluid responsiveness. We planned to evaluate the correlation between the internal jugular vein collapsibility index (IJVCI) and PSH in cesarean section patients. Methods Ninety-one parturients who underwent elective lower segment cesarean section with a singleton pregnancy were recruited. Preoperatively, patients were placed in a supine position with a 15-degree left lateral tilt. Maximum (at the end of expiration) and minimum (at the end of inspiration) IJV diameters (mm) and IJVCI were assessed using M-mode imaging during spontaneous and deep breathing. Spinal anaesthesia was performed at the L3-4 or L4-5 level. Systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, respiratory rate, and SpO2 were recorded from baseline till the delivery of the baby. Results Among 91 patients, 40 (45.5%) patients had at least one episode of hypotension. Demographic variables and baseline vitals were comparable between the hypotensive and normotensive groups (p>0.05). In spontaneous and deep breathing, IJV diameter at the end-expiration (IJVdmax), end-inspiration (IJVdmin), and IJVCI amongst both hypotensive and non-hypotensive pregnant women were statistically similar. Receiver Operating Characteristic (ROC) curve analysis showed that during spontaneous breathing, using a cut-off point of 29.5%, IJVCI had a sensitivity and specificity of 70% and 23%, respectively, for predicting PSH; whereas during deep breathing, IJVCI had a sensitivity and specificity of 77% and 27%, respectively, for predicting the same using a cut-off value of 37.5%. Conclusion We conclude that internal jugular vein parameters such as maximum diameter, minimum diameter, and IJVCI during spontaneous and deep breathing cannot be used as reliable predictors of post-spinal hypotension in pregnant patients undergoing elective cesarean section.

Assessment of retinal vein pulsation through video-ophthalmoscopy and simultaneous biosignals acquisition.

The phenomenon of retinal vein pulsation is still not a deeply understood topic in retinal hemodynamics. In this paper, we present a novel hardware solution for recording retinal video sequences and physiological signals using synchronized acquisition, we apply the photoplethysmographic principle for the semi-automatic processing of retinal video sequences and we analyse the timing of the vein collapse within the cardiac cycle using of an electrocardiographic signal (ECG). We measured the left eyes of healthy subjects and determined the phases of vein collapse within the cardiac cycle using a principle of photoplethysmography and a semi-automatic image processing approach. We found that the time to vein collapse (Tvc) is between 60 ms and 220 ms after the R-wave of the ECG signal, which corresponds to 6% to 28% of the cardiac cycle. We found no correlation between Tvc and the duration of the cardiac cycle and only a weak correlation between Tvc and age (0.37, p = 0.20), and Tvc and systolic blood pressure (-0.33, p = 0.25). The Tvc values are comparable to those of previously published papers and can contribute to the studies that analyze vein pulsations.

Evaluation of the Effect of Interscalene Brachial Plexus Block on Intracranial Pressure Using Optic Nerve Sheath Diameter and Internal Jugular vein Collapsibility Index.

To determine the effect of single-shot interscalene brachial plexus (ISBP) block on intracranial pressure (ICP) by evaluating the extravascular volume effect of the medicine on the internal jugular vein (IJV). Interventional study. Department of Anaesthesiology and Reanimation, Sivas Cumhuriyet University, Sivas, Turkey, from January to June 2022. Thirty-four patients were included in this prospective clinical study. All patients had single-shot ISBP block with 25 ml of local anaesthetic. Optic nerve sheath diameter (ONSD), maximum (Dmax) and minimum (Dmin) diameters of IJV and IJV collapsibility index (IJV-CI) were recorded before the block (basal), 20 minutes, and 60 minutes after the block. Twenty-nine patients had higher ONSD values at 60th minute compared to their basal values. There were negative correlations between the changes of ONSD and IJVCI (r=0.616, p<0.001) and ONSD and Dmax (r=0.581, p<0.001) in time period between basal and 20th minute. There were negative correlations between the changes of ONSD and IJVCI (r=0.518, p=0.002), ONSD and Dmax (r=0.664, p<0.001) in time period between basal and 60th minute. Single-shot ISBP block with 25 ml of local anaesthetic may be a factor that increases ICP. Repeated intraoperative ONSD measurements are recommended in patients operated with ISBP block. Interscalene Brachial Plexus Block, Intracranial pressure, Optic nerve sheath diameter, Internal jugular vein collapsibility index.

Ultrasound-guided estimation of internal jugular vein collapsibility index in patients with shock in emergency department.

To correlate ultrasound-guided estimation of Internal Jugular Vein Collapsibility Index (IJV-CI) with inferior vena cava CI (IVC-CI) and invasively monitored central venous pressure (CVP) in patients with shock in the emergency medicine department. A prospective observational study was done in the emergency department (ED). The study was conducted over 15 months (November 2019 to April 2021). It included patients more than 18 years presenting to the ED in shock. The IJV and IVC diameter and cross-sectional area were measured using ultrasound. The corresponding collapsibility indexes were then calculated and correlated with the invasively monitored CVP of the patient. Data were then analyzed using the Statistical Package for the Social Science (SPSS): Version 23 for windows. Pearson's correlation was used between CVP and collapsibility indexes. The mean (±standard deviation) age of the patients was 49.01 (±15.6). There was a 47 (64%) male predominance which outnumbered females 26 (36%). The correlation coefficient was statistically significant between CVP and the collapsibility indices for various IJV and IVC parameters. The highest correlation (r = -0.541, P = 0.005) was seen between IVC-CI (CI 5) and CVP. This was followed by a correlation seen at a 30° position for IJV CI (cross-sectional area) with CVP (r = -0.453, P = 0.001). Similarly, the correlation between IJV CI (AP diameter) and CVP, followed (r = -0.412, P = 0.008) was statistically significant. Both IJV and IVC collapsibility indices correlated significantly with invasively measured CVP. Hence, they present as an effective tool in fluid resuscitation in patients with shock in ED.

Pre-anaesthetic ultrasonographic assessment of neck vessels as predictors of spinal anaesthesia induced hypotension in the elderly: A prospective observational study

ABSTRACT Background Increased age has been linked to the development of spinal anaesthesia induced hypotension (SAIH) and increased the risk of perioperative complications. The internal jugular vein collapsibility index (IJV-CI), rates of change in IJV diameter (ΔIJV-D) and IJV area (ΔIJV-A) in the supine and Trendelenburg positions, and carotid intima-media thickness (CIMT) were evaluated as predictors of SAIH in the senior population. Materials and methods This prospective Cohort was conducted at the Cairo University Hospitals. Seventy-one patients scheduled for elective procedures under spinal anaesthesia of ASA I–III, over 60 years and BMI less than 30 kg/m2. The right IJV was assessed ultrasonographically in supine and Trendelenburg postures, as well as CIMT. The primary outcome was the IJV- CI as predictor of SAIH while ΔIJV-D and ΔIJV-A with posture and CIMT in prediction of SAIH were assigned as secondary outcomes. Results SAIH was shown in forty-seven (66.2%) of patients. IJV-CI, ΔIJV-A and ΔIJV-D increased significantly in Hypotensive group (median 38.09, IQR (23.61–50), 0.393 (0.2–0.52) and 0.213 (0.12–0.34) respectively) in comparison to Non-hypotensive group (26.05 (10.32–34.08), 0.167 (0.03–0.48) and 0.074 (0.02–0.29) respectively) (p-value <0.05). IJV-CI showed AUROC of 0.699 and 95% CI of 0.578–0.802 (p-value = 0.002) with cut-off value ≥0.34.4, 61.70% sensitivity, 79.17% specificity, 85.3% PPV and 51.4% NPV. Conclusions Preanesthetic IJV-CI and ΔIJV-D from the supine to the Trendelenburg position were moderate predictors of SAIH. Results suggested that IJV-CI is > 34.4% and a ΔIJV-D is of ≥ 0.11 to be the threshold levels, while CMIT could not predict SAIH.

Pre-operative Ultrasonographic Evaluation of the Internal Jugular Vein Collapsibility Index and Inferior Vena Cava Collapsibility Index to Predict Post Spinal Hypotension in Pregnant Women Undergoing Caesarean Section.

BackgroundPost spinal anesthesia hypotension (PSAH) is frequently encountered in anesthetic practice, especially during cesarean section. Ultrasound is a safe and easy technique for hemodynamic monitoring.ObjectivesThis study was conducted to assess the efficacy of pre-operative inferior vena cava collapsibility index (IVCCI) and internal jugular vein collapsibility index (IJVCI) in predicting PSAH.MethodsThis cross-sectional blinded study included 55 pregnant females prepared for elective cesarean section. They were divided into two groups based on the incidence of PSAH: (1) cases with PSAH (26 cases); and (2) cases without PSAH (29 cases). All the cases underwent ultrasound-guided measurement of IVCCI and IJVCI. The efficacy of these parameters was assessed in predicting PSAH.ResultsCases in both groups expressed non-significant differences regarding demographic data. However, IVCCI had mean values of 38.27 and 23.97%, while IJVCCI had mean values of 46.50 and 33.41%, respectively, in cases with and without PSAH. For IVCCI, using a cut-off point of 33% had sensitivity and specificity (84.6 and 93.1%, respectively) for predicting PSAH, with a diagnostic accuracy of 89.1%. IJVCI had sensitivity and specificity of 84.6 and 82.8%, respectively, for predicting the same complication using a cut-off value of 38.5%.ConclusionIVCCI and IJVCI are efficacious and reliable tools in predicting PSAH in pregnant ladies undergoing cesarean section, with a slight superiority for IVCCI regarding specificity and accuracy.

Ultrasound imaging and central venous pressure in spontaneously breathing patients: a comparison of ultrasound-based measures of internal jugular vein and inferior vena cava.

Ultrasound evaluation of inferior vena cava and internal jugular vein dia-meters predicts the intravascular volume status in critical patients. The aim of the present study was to determine which ultrasound-derived index is most strongly associated with central venous pressure (CVP). Furthermore, we determined the utility of selected variables in predicting low volume status (CVP < 8 mmHg). All patients underwent a transthoracic echocardiogram, vascular ultrasound examination, invasive central venous pressure, and intra-abdominal pressure determination. The following indexes were calculated: inferior vena cava diameter, internal jugular vein maximum diameter, collapsibility index, and internal jugular vein ratio. 41 spontaneously breathing patients were recruited. Central venous pressure significantly correlated with inferior vena cava diameter ( r = 0.35, P = 0.02), internal jugular vein ratio ( r = 0.35, P = 0.03), and internal jugular vein maximum diameter ( r = 0.58, P < 0.001). The inferior vena cava collapsibility index did not show any association. The areas under the receiver operating characteristic curves to discriminate a low central venous pressure (< 8 mmHg) were the following: internal jugular vein diameter 0.80 (95% CI: 0.63-0.90); inferior vena cava diameter 0.66 (95% CI: 0.49-0.80); and internal jugular vein ratio 0.68 (95% CI: 0.51-0.82). The internal jugular vein diameter, the internal jugular vein ratio, and the inferior vena cava diameter showed a significant correlation with central venous pressure. In particular, the internal jugular vein diameter showed good accuracy in predicting a low central venous pressure.

Comparison of subclavian vein to inferior vena cava collapsibility by ultrasound in acute heart failure: A pilot study.

BackgroundManagement of acute decompensated heart failure (ADHF) requires accurate assessment of relative intravascular volume, which may be technically challenging. Inferior vena cava (IVC) collapsibility with respiration reflects intravascular volume and right atrial pressure (RAP). Subclavian vein (SCV) collapsibility may provide an alternative.HypothesisThe purpose of this study was to examine the relationship between SCV collapsibility index (CI) and IVC CI in ADHF.MethodsThis was a prospective study of non‐ventilated patients with ADHF who had paired IVC and SCV ultrasound assessments. As SCV CI is highly position‐dependent, measurements were performed supine at 30–45°.ResultsThirty‐three patients were included with 36 encounters. The sample size was adequately powered for receiver‐operator characteristic (ROC) analysis. SCV CI correlated with IVC CI during relaxed breathing (R = .65, n = 36, p < .001) and forced inhalation (R = .47, n = 36, p = .0036). SCV CI < 22% and >33% corresponded to IVC CI < 20% and >50% suggesting hypervolemia (sensitivity/specificity: 72%) and hypovolemia (sensitivity/specificity: 78%), respectively. Moderate to severe tricuspid regurgitation (TR) compared to less than moderate TR was associated with lower SCV CI (medians: 12.4% vs. 25.3%, p = .022) and IVC CI (medians: 9.6% vs. 35.6%, p = .0012). SCV CI and IVC CI were not significantly different among chronic kidney disease stages.ConclusionIn non‐ventilated ADHF, SCV CI at 30–45° correlates with paired IVC CI, and may provide an alternative to IVC CI for assessment of relative intravascular volume, which may facilitate clinical management. Moderate to severe TR decreases SCV CI and IVC CI and may result in overestimation of relative intravascular volume.

Is There an Optimal Positive End-expiratory Pressure to Measure the Internal Jugular Vein Collapsibility Index? A Pilot Study in Mechanically Ventilated Patients

Background: Hemodynamic monitoring its early stabilization is very important in critically ill patients. Evaluating the Internal jugular vein diameter during respiratory cycles by the means of Point-of care ultrasound provides an important, easily available and precise index for monitoring hemodynamic status; a new method which is called Internal Jugular Vein Collapsibility Index (IJV-CI). Any events that alters intrathoracic volumes and pressures may affect this index. In this study we investigate the effects of various levels of positive end-expiratory pressure on this index. Methods: Thirty mechanically ventilated patients were studied. We used three different PEEP levels (0, 5 and 10 cmH2o) and point-of-care ultrasound evaluation of IJV (Internal Jugular Vein) diameter to determine the IJV-CI. The analysis were performed using SPSS V.25.0. Results: Patients were included men (76.6%) and women (33.3%). The mean age of patients was 39.65±3.4 for men and 42.71± 9.34 for women. The IJV-CI were 20.71±11.77 and 24.25±11.46 in PEEP=0 and PEEP=10 cmH20 groups respectively. In 5cmH20-PEEP group median and interquartile range were 16.45(14.8). The IJV-CI in three different PEEP levels were not statistically significantly different. Conclusion: According to the finding of this study, we found no evidence of an optimal PEEP level to measure The IJV-CI.

Cytotoxic function of xylanase VdXyn4 in the plant vascular wilt pathogen Verticillium dahliae.

Phytopathogen xylanases play critical roles in pathogenesis, likely due to their ability to degrade plant structural barriers and manipulate host immunity. As an invader of plant xylem vessels, the fungus Verticillium dahliae is thought to deploy complex cell wall degrading enzymes. Comparative genomics analyses revealed that the V. dahliae genome encodes a family of six xylanases, each possessing a glycosyl hydrolase 11 domain, but the functions of these enzymes are undetermined. Characterizing gene deletion mutants revealed that only V. dahliae xylanase 4 (VdXyn4) degraded the plant cell wall and contributed to the virulence of V. dahliae. VdXyn4 displayed cytotoxic activity and induced a necrosis phenotype during the late stages of infection, leading to vein and petiole collapse that depended on the enzyme simultaneously localizing to nuclei and chloroplasts. The internalization of VdXyn4 was in conjunction with that of the plasma membrane complexLeucine-rich repeat (LRR)-receptor-like kinase suppressor of BIR1-1 (SOBIR1)/LRR-RLK BRI1-associated kinase-1 (BAK1), but we could not rule out the possibility that VdXyn4 may also act as an apoplastic effector. Immune signaling (in the SA–JA pathways) induced by VdXyn4 relative to that induced by known immunity effectors was substantially delayed. While cytotoxic activity could be partially suppressed by known effectors, they failed to impede necrosis in Nicotiana benthamiana. Thus, unlike typical effectors, cytotoxicity of VdXyn4 plays a crucial intracellular role at the late stages of V. dahliae infection and colonization, especially following pathogen entry into the xylem; this cytotoxic activity is likely conserved in the corresponding enzyme families in plant vascular pathogens.

COMPARISON OF NONINVASIVE CENTRAL VENOUS PRESSURE MEASUREMENT METHODS: INTERNAL JUGULAR VEIN VERSUS VENA CAVA INFERIOR

Objective&#x0D; Central venous pressure measurement is an effective&#x0D; method to detect the volume status of the patients.&#x0D; However, life-threatening complications such as&#x0D; pneumothorax may occur. We assume that ultrasonographic&#x0D; measurements may be used as a surrogate&#x0D; of invasive central venous pressure.&#x0D; Materials and Methods&#x0D; Our study has been conducted between January&#x0D; 2015-January 2016 on 81 patients who were over&#x0D; the age of 18 and to whom a central venous catheter&#x0D; has been placed in the internal jugular vein (IJV)&#x0D; in our Emergency Intensive Care Unit. The height of&#x0D; the blood column in the internal jugular vein, internal&#x0D; jugular vein collapsibility index (IJV-CI) and the caval&#x0D; index (CI) of vena cava inferior have been measured&#x0D; by ultrasound. Then, invasive central venous pressure&#x0D; (CVP) has been measured and the patients were&#x0D; separated into two groups as low CVP and normal&#x0D; CVP groups and statistically significance was sought&#x0D; between groups in regard of these three methods.&#x0D; Results&#x0D; The mean age was 68.58±13.33 years. Fifty-four of&#x0D; the patients (66.6%) were male. Forty-six patients&#x0D; (56.8%) were mechanically ventilated. Low CVP&#x0D; group consisted of 62 patients (76.5%). Mean invasive&#x0D; CVP was 4.83±4.26 mmHg. There were significant&#x0D; correlations between IJV-CI and invasive CVP along&#x0D; with the CI (r=-0.267, p=0.016 and r=0.319, p=0.04,&#x0D; respectively), IJV height method and CI as well as&#x0D; invasive CVP measurement (r=-0.231, p=0.03 and&#x0D; r=0.357, p=0.01, respectively). The CI did not yield&#x0D; any correlation between invasive CVP measurement&#x0D; (r=-0.010, p=0.368).&#x0D; Conclusion&#x0D; Noninvasive central venous pressure measurement&#x0D; methods may be used as a surrogate for invasive&#x0D; central venous pressure levels. The IJV-CI may be&#x0D; a useful tool to estimate CVP. Measurements of IJV&#x0D; yields better results than the measurements from&#x0D; vena cava inferior (VCI) especially in volume depleted&#x0D; patients.

Do Large Vessels Affect Hemodynamic Monitoring by Near Infrared Spectroscopy?

Near Infrared Spectroscopy (NIRS) is a widely used technique to assess local tissue oxygenation and blood volume. However, several confounding factors complicate its interpretation. Among these is the potential influence exerted on NIRS variables by large vessels possibly located within the sample volume. This influence is generally neglected, according to the consideration that infrared light entering a large vessel is completely absorbed and thus not backscattered to the receiving optode. On the other hand, vessel size changes vary the amount of light absorbed and thus should profoundly affect NIRS variables. Aim of this study is to ascertain whether vessel size changes, as produced by venous occlusion, can affect NIRS blood volume indices. NIRS monitoring was performed over the basilic vein (BV) in 12 subjects (9 M – 3 F; age 31±8 yr) simultaneously to ultrasound assessment of BV size at the same location, while a second NIRS probe was positioned on the biceps muscle (BM), over a virtually vessel-free area. The arm was elevated (~60°) to induce vein collapse and subjected to venous occlusion, according to two pressure profiles: slow (from 0 to 60 mmHg in 135 s; plateau, 30 s; deflation to 0 mmHg in 135 s) and fast (step inflation to 40 mmHg maintained for 30 s). The cross-sectional area of the BV was continuously recorded along with a NIRS blood volume indicator, i.e., the total hemoglobin concentration (tHb). The tHb index detected a blood volume increase 1.7 and 2.5 times larger over BV than over BM during both slow (p<0.01) and fast (p<0.01) venous occlusions, respectively. The responses to slow venous occlusion exhibited different time courses: tHbBM exhibited a rather linear rise with time, while tHbBV showed a steeper rise at the beginning of the response, resulting in a higher convexity of the curve (p=0.01), similar to the time course of BV size. Similar patterns could be observed also in response to fast occlusions (p<0.05) and also on THI tracings (p<0.05 for both slow and fast occlusions). On average, tHbBV tracings were better correlated to BV area tracings (r=0.90) than tHbBM (r=0.83, p<0.001, after Z-transform), in response to the slow occlusion. In addition, respiratory oscillations in BV size were observed in tHbBV and not in tHbBM. In conclusion, these results challenge the long standing belief that large vessels are excluded from the NIRS sample volume. Experimental evidence strongly supports the concept that size changes of large vessels may profoundly affect NIRS variables. Neglecting this possibility may potentially introduce relevant artefacts in NIRS variables in all conditions affecting venous blood pressure, such as postural changes, or the extravascular pressure, such as muscle contraction.