Effects of ipsilateral tilt position on the cross-sectional area of the subclavian vein and the clinical performance of subclavian vein catheterization: a prospective randomized trial.

BACKGROUND: The cross-sectional area of the subclavian vein (csSCV) is a crucial factor in the successful catheterization of the subclavian vein. This randomized controlled study investigated the effects of the csSCV on landmark-based subclavian vein catheterization. METHODS: This study was performed using a two-stage protocol. During stage I, the csSCV was measured in 17 patients placed in the supine, 20° ipsilateral tilt, and 20° contralateral tilt positions in a random order. During stage II, landmark-based subclavian vein catheterization was randomly performed in patients placed in either the supine (group S, n = 107) or the ipsilateral tilt (group I, n = 109) position. The primary outcome measure was the csSCV in stage I and the primary venipuncture success rate in stage II. Secondary outcome measures were the time to successful venipuncture, the total catheterization time, the first-pass success rate, and the incidence of mechanical complications during catheterization. RESULTS: The csSCV was significantly larger in the ipsilateral tilt than in either the supine or contralateral tilt position (1.01 ± 0.35 vs. 0.84 ± 0.32 and 0.51 ± 0.26 cm2, P = .006 and < .001, respectively). The primary venipuncture success rate did not differ significantly between the group S and I (57.0 vs. 64.2%, P = .344). There were also no significant differences in the secondary outcome measures of the two groups. CONCLUSIONS: The csSCV was significantly larger in patients placed in the ipsilateral tilt than in the supine position, but the difference did not result in better clinical performance of landmark-based subclavian vein catheterization. TRIAL REGISTRATION: NCT03296735 for stage I ( ClinicalTrials.gov , September 28, 2017) and NCT03303274 for stage II ( ClinicalTrials.gov , October 6, 2017).

[Evaluation via ecocolordoppler before creating a vascular access for hemodyalisis: a monocentric experience].

The use of a preoperative echocolordoppler improves the clinical evaluation because provides anatomical and hemodynamic information that make it an important tool in planning vascular access strategy. The preoperative ultrasound study of the vessels can significantly reduce the failure rate and the incidence of complications of vascular access. We describe the experience of our center, lasting 10-year, where the ultrasound assessment was performed in all patients before the creation of vascular access. Indeed, ultrasound reduces the rate of fistula failure and increases the utilization of fistula, allowing proper selection of vessels. In addition, the presence of the vascular access team has allowed us to achieve quite satisfactory results.

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

BACKGROUND: Increasing the size of the central veins is required to increase the success rate of central line placement and decrease complication risk. Right-sided approach for the central veins, Valsalva maneuver, and Trendelenburg position have been recommended, but these may not be available for some cases. This study aimed to determine a more convenient patient position that can result in the largest central vein diameter. METHODS: Recruited subjects were placed in 60° and 30° upper body elevation, supine position, and 30° and 60° lower body elevation, and lumbar elevation (LE) was consecutively performed, with one position maintained for 10 min. Diameters of the subclavian vein (SCV) and internal jugular vein (IJV) were measured using high-resolution two-dimensional ultrasonography at each position. RESULTS: The most suitable position on the ordinary bed for increasing central vein diameter was LE. The maximum and minimum SCV and IJV diameters in LE were significantly larger than those in the supine position (SCV: coefficients -0.633 and -0.863, p = 0.08 and 0.011, respectively; IJV: coefficients -1.09 and -1.15, p < 0.001 and = 0.001, respectively). Leg elevation for 10 min failed to dilate the central vein diameter. CONCLUSION: The LE without leg elevation produced a greater and more significant increase in central vein diameter than the supine position and may be useful for central line placement.

Subclavian Vein Puncture As an Alternative Method of Blood Sample Collection in Rats.

Blood collection with enough blood volume is essential in animal experiments. Blood collection from the tail vein of rats is popular and less stressful compared to other more aggressive methods such as retro-orbital plexus sample collection. However, this blood collection method is sometimes limited by an unsatisfactory success rate. Here, we introduce a method for blood collection through the subclavian vein puncture. The subclavian vein is located just under the clavicle and this vein is large enough to fulfill the volume requirements of blood collection. Our results show that this method is safe and applicable for blood collection sampling with the required blood volume. Blood collection through the subclavian vein puncture could serve as an alternative blood collection method in case of failed tail vein blood sampling in rats.

Central venous pressure and ultrasonographic measurement correlation and their associations with intradialytic adverse events in hospitalized patients: A prospective observational study.

PURPOSE: To investigate correlation of central venous pressure (CVP) with ultrasonographic measurement of central veins, along with association between these variables and occurrence of intradialytic adverse events in hospitalized patients. MATERIALS AND METHODS: Patients requiring hemodialysis via dialysis catheter were prospectively enrolled. CVP measurements through catheter, internal jugular vein aspect ratio, subclavian vein collapsibility, inferior vena cava (IVC) maximal diameter, and IVC collapsibility were recorded before and after hemodialysis. Predictive accuracy of ultrasonographic measurements in discriminating high versus low CVP and their association with intradialytic adverse events were evaluated. Area under receiver operating characteristic curves (AUCs) were calculated. RESULTS: Fifty-nine patients were enrolled. Median (interquartile range) pre- and post-dialysis CVPs were 8 (4-13)mmHg and 6 (3-10)mmHg, respectively (P<0.01). In pre-dialysis, IVC collapsibility had the highest AUC (0.79, P<0.01) to predict CVP >8mmHg. In post-dialysis, IVC maximal diameter had the highest AUC (0.86, P<0.01) to predict CVP ≤4mmHg. Fifteen patients (25%) had adverse events. Neither pre-dialytic CVP nor ultrasonographic variables were associated with occurrence of adverse events. CONCLUSIONS: Highest accuracy in predicting low and high CVP was observed with ultrasonographic assessment of IVC diameter and collapsibility. Adverse events were not predicted by pre-dialytic CVP or ultrasonographic measurements.

The Effect of Head Position on the Cross-Sectional Area of the Subclavian Vein.

In 41 healthy volunteers, we investigated the cross-sectional area (CSA) of the subclavian vein (SCV) in the following head positions: neutral and 30° head rotation toward the contralateral or ipsilateral sides. Significant differences were observed in the CSA of the SCV at 3 different head positions: contralateral 30° versus neutral, -0.05 cm (95% confidence interval, -0.08 to -0.03); contralateral 30° versus ipsilateral 30°, -0.15 cm (-0.19 to -0.12); neutral versus ipsilateral 30°, -0.10 cm (-0.13 to -0.07); all Pcorrected< .001). For SCV catheterization, 30° head rotation to the ipsilateral side provided significant improvements in the CSA compared with the other head positions.

[Estimation of the jugular venous pressure]. / Het beoordelen van de centraalveneuze druk.

Estimation of jugular venous pressure (JVP) is valuable for the differentiation between dyspnoea of cardiac or pulmonary origin, and for determining the cause of oedema. JVP assessments are useful for evaluation of treatment of right ventricular failure. The correlation between non-invasive JVP and invasive measurement of the central venous pressure (CVP) is remarkably better than previously reported. Correlation between JVP - determined via the external jugular vein - and CVP is excellent when the outcomes are categorised into low, normal and elevated pressure. Optimal measurement configurations include: extended expiration (without Valsalva manoeuvre), and during ventricular diastole. In the literature, these measurement configurations concerning the respiratory cycle and cardiac cycle have not been applied uniformly. To investigate in detail the correlation between JVP and CVP, the methods need to be standardized, and tests performed simultaneously and correctly.

Blood temperature and perfusion to exercising and non-exercising human limbs.

NEW FINDINGS: What is the central question of this study? Temperature-sensitive mechanisms are thought to contribute to blood-flow regulation, but the relationship between exercising and non-exercising limb perfusion and blood temperature is not established. What is the main finding and its importance? The close coupling among perfusion, blood temperature and aerobic metabolism in exercising and non-exercising extremities across different exercise modalities and activity levels and the tight association between limb vasodilatation and increases in plasma ATP suggest that both temperature- and metabolism-sensitive mechanisms are important for the control of human limb perfusion, possibly by activating ATP release from the erythrocytes. Temperature-sensitive mechanisms may contribute to blood-flow regulation, but the influence of temperature on perfusion to exercising and non-exercising human limbs is not established. Blood temperature (TB ), blood flow and oxygen uptake (V̇O2) in the legs and arms were measured in 16 healthy humans during 90 min of leg and arm exercise and during exhaustive incremental leg or arm exercise. During prolonged exercise, leg blood flow (LBF) was fourfold higher than arm blood flow (ABF) in association with higher TB and limb V̇O2. Leg and arm vascular conductance during exercise compared with rest was related closely to TB (r(2) = 0.91; P < 0.05), plasma ATP (r(2) = 0.94; P < 0.05) and limb V̇O2 (r(2) = 0.99; P < 0.05). During incremental leg exercise, LBF increased in association with elevations in TB and limb V̇O2, whereas ABF, arm TB and V̇O2 remained largely unchanged. During incremental arm exercise, both ABF and LBF increased in relationship to similar increases in V̇O2. In 12 trained males, increases in femoral TB and LBF during incremental leg exercise were mirrored by similar pulmonary artery TB and cardiac output dynamics, suggesting that processes in active limbs dominate central temperature and perfusion responses. The present data reveal a close coupling among perfusion, TB and aerobic metabolism in exercising and non-exercising extremities and a tight association between limb vasodilatation and increases in plasma ATP. These findings suggest that temperature and V̇O2 contribute to the regulation of limb perfusion through control of intravascular ATP.

Differences between internal jugular vein and vertebral vein flow examined in real time with the use of multigate ultrasound color Doppler.

BACKGROUND AND PURPOSE: The hypothesis that MS could be provoked by a derangement of the blood outflow from the brain has been largely discredited. In part, it was because data on the normal pattern of outflow are scarce and obtained with different methods. The aim of this study was to evaluate the normal pattern of outflow for the vertebral and internal jugular veins in healthy subjects with multigate color Doppler. MATERIALS AND METHODS: Twenty-five volunteers were studied to assess vessel area, mean velocity, and flow for the vertebral and internal jugular veins in the supine and sitting positions. RESULTS: In the sitting position, flow decreases, both in vertebral veins and internal jugular veins, as the total vessel area decreases (from 0.46 ± 0.57 to 0.09 ± 0.08 cm(2)), even if the mean velocity increases (from 12.58 ± 10.19 to 24.14 ± 17.60 cm/s). Contrary to what happens to the blood inflow, outflow in the supine position, through vertebral and internal jugular veins, is more than twice the outflow in the sitting position (739.80 ± 326.32 versus 278.24 ± 207.94 mL/min). In the sitting position, on application of very low pressure to the skin with the sonography probe, internal jugular veins rarely appear to occlude. A pronounced difference of diameter between internal jugular veins was present in approximately one-third of subjects. CONCLUSIONS: Our results support the view that other outflow pathways, like the vertebral plexus, play a major role in the normal physiology of brain circulation and must be assessed to obtain a complete picture of blood outflow.

Sonographic evaluation of intravascular volume status in the surgical intensive care unit: a prospective comparison of subclavian vein and inferior vena cava collapsibility index.

BACKGROUND: Traditional methods for intravascular volume status assessment are invasive and are associated significant complications. While focused bedside sonography of the inferior vena cava (IVC) has been shown to be useful in estimating intravascular volume status, it may be technically difficult and limited by patient factors such as obesity, bowel gas, or postoperative surgical dressings. The goal of this investigation is to determine the feasibility of subclavian vein (SCV) collapsibility as an adjunct to IVC collapsibility in intravascular volume status assessment. METHODS: A prospective study was conducted on a convenience sample of surgical intensive care unit patients to evaluate interchangeability of IVC collapsibility index (IVC-CI) and SCV-CI. After demographic and acuity of illness information was collected, all patients underwent serial, paired assessments of IVC-CI and SCV-CI using portable ultrasound device (M-Turbo; Sonosite, Bothell, WA). Vein collapsibility was calculated using the formula [collapsibility (%) = (max diameter - min diameter)/max diameter × 100%]. Paired measurements from each method were compared using correlation coefficient and Bland-Altman measurement bias analysis. RESULTS: Thirty-four patients (mean age 56 y, 38% female) underwent a total of 94 paired SCV-CI and IVC-CI sonographic measurements. Mean acute physiology and chronic health evaluation II score was 12. Paired SCV- and IVC-CI showed acceptable correlation (R(2) = 0.61, P < 0.01) with acceptable overall measurement bias [Bland-Altman mean collapsibility difference (IVC-CI minus SCV-CI) of -3.2%]. In addition, time needed to acquire and measure venous diameters was shorter for the SCV-CI (70 s) when compared to IVC-CI (99 s, P < 0.02). CONCLUSIONS: SCV collapsibility assessment appears to be a reasonable adjunct to IVC-CI in the surgical intensive care unit patient population. The correlation between the two techniques is acceptable and the overall measurement bias is low. In addition, SCV-CI measurements took less time to acquire than IVC-CI measurements, although the clinical relevance of the measured time difference is unclear.

Pressão venosa central em cateter femoral: correlação com acesso superior após cirurgia cardíaca / Central venous pressure in femoral catheter: correlation with superior approach after heart surgery

OBJETIVO: É comum a obtenção de acesso venoso femoral em pacientes submetidos a cirurgia cardíaca em associação ou como alternativa ao acesso superior (veia jugular interna ou veia subclávia). O objetivo deste estudo foi comparar as medidas de pressão venosa central (PVC) em dois sítios diferentes (superior vs. femoral). MÉTODOS: Estudo prospectivo e aberto com 60 pacientes submetidos a cirurgia cardíaca no período de julho a novembro de 2006. Foram obtidas três medidas de cada paciente em cada sítio (admissão, 6 e 12 horas após a cirurgia) em duas inclinações diferentes da cabeceira do leito (zero e 30 graus), totalizando 720 medidas. RESULTADOS: Cinqüenta e cinco por cento dos pacientes foram submetidos a revascularização do miocárdio, 38 por cento a cirurgia valvar e 7 por cento a outras cirurgias. A média de PVC ± desvio padrão (DP) medida no acesso superior foi de 13,0 ± 5,5 mmHg (zero grau) e 13,3 ± 6,1 mmHg (30 graus), enquanto que as medidas no acesso inferior foram 11,1 ± 4,9 mmHg (zero grau) e 13,7 ± 4,6 mmHg (30 graus). A correlação linear (r) entre as medidas nos dois sítios foi de 0,66 (zero grau) e 0,53 (30 graus), ambas com p < 0,0001. CONCLUSÃO: A PVC pode ser medida com acurácia no acesso venoso femoral no pós-operatório imediato de cirurgia cardíaca, com melhor correlação linear obtida com as medidas feitas com a cabeceira do leito posicionada em zero grau.

OBJECTIVE: It is common to obtain femoral venous approach in patients undergoing combined heart surgery or as an alternative to superior approach (internal jugular vein or subclavian vein). The aim of this study was to compare the measures of central venous pressure (CVP) at two different sites (superior versus femoral). METHODS: We prospectively and openly allocated 60 patients who underwent heart surgery between July from November 2006. Three measures were obtained from each patient at each site (admission, 6 and 12 hours after surgery) in two different inclinations of the headboard (zero and 30 degrees) totaling 720 measures. RESULTS: Fifty five percent of patients who underwent coronary artery bypass grafting, 38 percent heart valve surgery and 7 percent other surgeries. The mean of CVP ± standard deviation (SD) measured in superior approach was 13.0 ± 5.5 mmHg (zero degree) and 13.3 ± 6.1 mmHg (30 degrees) while the measures in inferior approach were 11.1 ± 4.9 mmHg (zero degree) and 13.7 ± 4.6 mmHg (30 degrees). The linear correlation (r) between the measures in both sites was 0.66 (zero degree) and 0.53 (30 degrees), both with p value<0.0001. CONCLUSION: The CVP can be measured with accuracy in the femoral venous approach in the immediate postoperative period of heart surgery with better linear correlation obtained with the measures made with the headboard positioned at zero degree.

The influence of passive leg elevation on the cross-sectional area of the internal jugular vein and the subclavian vein in awake adults.

The aim of this study was to evaluate the influence of passive leg elevation and Trendelenburg position on the cross-sectional area (CSA) of the internal jugular (II) and subclavian veins (SCV). Ultrasound imaging was used for the following measurements of both the IJV and SCV baseline in the supine position (control); Trendelenburg position 15 degrees; reverse Trendelenburg position 15 degrees and passive leg elevation 50 degrees. Twenty healthy male volunteers were studied. Mean CSA of the IJV was 1.12 +/- 0.57 cm2 in control, 1.66 +/- 0.67 cm2 in the Trendelenburg position (P < 0.0001 vs. control), 0.38 +/- 0.23 cm2 in the reverse Trendelenburg position (P < 0.0001 vs. control), and 1.40 +/- 0.64 cm2 during passive leg elevation (P < 0.0001 vs. control). Mean CSA of the SCV was 0.92 +/- 0.23 cm2 in control, 0.98 +/- 0.17 cm2 in the Trendelenburg position, 0.86 +/- 0.21 cm2 in the reverse Trendelenburg position and 0.93 +/- 0.18 cm2 during passive leg elevation. The results indicate that passive leg elevation increases the CSA of the IJV, but has little effect on the SCV. The CSA of the IJV appears to be influenced more by gravitational factors than the SCV.

The clinical anatomy of the cephalic vein in the deltopectoral triangle.

Identification and recognition of the cephalic vein in the deltopectoral triangle is of critical importance when considering emergency catheterization procedures. The aim of our study was to conduct a cadaveric study to access data regarding the topography and the distribution patterns of the cephalic vein as it relates to the deltopectoral triangle. One hundred formalin fixed cadavers were examined. The cephalic vein was found in 95% (190 right and left) specimens, while in the remaining 5% (10) the cephalic vein was absent. In 80% (152) of cases the cephalic vein was found emerging superficially in the lateral portion of the deltopectoral triangle. In 30% (52) of these 152 cases the cephalic vein received one tributary within the deltopectoral triangle, while in 70% (100) of the specimens it received two. In the remaining 20% (38) of cases the cephalic vein was located deep to the deltopectoral fascia and fat and did not emerge through the deltopectoral triangle but was identified medially to the coracobrachialis and inferior to the medial border of the deltoid. In addition, in 4 (0.2%) of the specimens the cephalic vein, after crossing the deltopectoral triangle, ascended anterior and superior to the clavicle to drain into the subclavian vein. In these specimens a collateral branch was observed to communicate between the cephalic and external jugular veins. In 65.2% (124) of the cases the cephalic vein traveled with the deltoid branch of the thoracoacromial trunk. The length of the cephalic vein within the deltopectoral triangle ranged from 3.5 cm to 8.2 cm with a mean of 4.8+/-0.7 cm. The morphometric analysis revealed a mean cephalic vein diameter of 0.8+/-0.1 cm with a range of 0.1 cm to 1.2 cm. The cephalic vein is relatively large and constant, usually allowing for easy cannulation.

Central venous pressure in femoral catheter: correlation with superior approach after heart surgery.

OBJECTIVE: It is common to obtain femoral venous approach in patients undergoing combined heart surgery or as an alternative to superior approach (internal jugular vein or subclavian vein). The aim of this study was to compare the measures of central venous pressure (CVP) at two different sites (superior versus femoral). METHODS: We prospectively and openly allocated 60 patients who underwent heart surgery between July from November 2006. Three measures were obtained from each patient at each site (admission, 6 and 12 hours after surgery) in two different inclinations of the headboard (zero and 30 degrees) totaling 720 measures. RESULTS: Fifty five percent of patients who underwent coronary artery bypass grafting, 38% heart valve surgery and 7% other surgeries. The mean of CVP +/- standard deviation (SD) measured in superior approach was 13.0 +/- 5.5 mmHg (zero degree) and 13.3 +/- 6.1 mmHg (30 degrees) while the measures in inferior approach were 11.1 +/- 4.9 mmHg (zero degree) and 13.7 +/- 4.6 mmHg (30 degrees). The linear correlation (r) between the measures in both sites was 0.66 (zero degree) and 0.53 (30 degrees), both with p value<0.0001. CONCLUSION: The CVP can be measured with accuracy in the femoral venous approach in the immediate postoperative period of heart surgery with better linear correlation obtained with the measures made with the headboard positioned at zero degree.

Access flow, venous saturation, and digital pressures in hemodialysis.

BACKGROUND: A hemodialysis arteriovenous fistula (AVF) requires surgical modification in patients with cardiac overload or dialysis access-associated steal syndrome (DASS). Creation of an artificial stenosis (banding) within the AVF may be used, but this technique lacks the guidance of objective parameters. The aim of this pilot study was to identify indicators that reflect AVF flow in dialysis patients with either access-related cardiac overload (CO) or DASS requiring corrective surgery. METHODS: Patients underwent serial measurements of subclavian venous saturation (Sat(ven)), access flow (Flow(us)), and index digital pressures (P(dig)) during a corrective banding procedure. RESULTS: Data were obtained in 14 individuals (9 men; mean age, 53 +/- 6 years) during 16 studies (CO, n = 8; DASS, n = 8). Before surgery, correlations between preoperative flow, Sat(ven) and P(dig) were not significant. Stepwise banding of the AVF altered Sat(ven) in both groups from a mean of 91% +/- 1% (open AVF) to 84% +/- 2% (closed AVF, P < .001). The CO patients demonstrated a larger drop (-13%) compared with the DASS patients (-4%). Values of P(dig) increased from 68 +/- 9 to 90 +/- 9 mm Hg (P < .001), and both groups demonstrated a similar +23 mm Hg increase. In concert, the digital brachial index also significantly improved in all patients from 0.60% +/- 0.09% to 0.74% +/- 0.10%. Linearity was present between alterations in Flow(us) and Sat(ven) in all patients, but mostly in the CO patients (r(2) = 0.96). CONCLUSIONS: Stepwise banding of hemodialysis fistulas leads to dose-dependent decreases in flow and ipsilateral subclavian venous saturation combined with augmented digital pressures in patients with cardiac overload and dialysis associated steal syndrome. Intraoperative measurements of venous saturation and digital pressures may have the potential of guiding surgical correction in these patients.

Clinical review: alternative vascular access techniques for continuous hemofiltration.

Obtaining or maintaining vascular access for continuous hemofiltration can sometimes be problematic, especially in the child or adult in multiple organ failure with edema and/or coagulopathy. Problems commonly encountered include obstruction of the femoral vein by the catheter, insertion difficulties, safety concerns when cannulating the subclavian vein in coagulopathy, and catheter and circuit occlusion due to disseminated intravascular coagulation. For access in infants we describe a technique utilizing two single-lumen thin-walled vascular sheaths. For infants and small children initial access to the vein may be difficult due to edema or poor perfusion. For this situation we describe the 'mini-introducer' technique of securing the vein and facilitating subsequent insertion of a relatively large guide wire. At any age an alternative route to the subclavian vein, from above the clavicle, is potentially 'compressible' in the event of hemorrhage during the procedure. We remind the reader of the utility of ultrasound guidance for cannulation of the internal jugular and subclavian veins. And lastly we review the options for venous return via the umbilical vein in infants, and via the antecubital vein in larger children and adults.

Anomalous jugular veins system in an adult male cadaver.

This is an observation of anomaly of the jugular veins system bilaterally. Both right and left external jugular veins drained into the subclavian veins. The right anterior jugular vein drained into the confluence of internal jugular and the subclavian veins as they join to form the right brachiocephalic vein. The left anterior jugular vein drained into the internal jugular vein just before it joins the subclavian vein to form the left brachiocephalic vein. Both the external and anterior jugular veins were smaller than normal on the right, moreover, the right external jugular vein was smaller than the right anterior jugular vein. The right internal jugular vein was almost twice the size of the left internal jugular vein. The right subclavian vein was larger that its left counterpart. The current observations are being reported for the first time. The anomalies reported in this observation involve most veins of the jugular system and therefore suggests that anomalies of a particular vein may affect the size and symmetry of veins that drain into it, or communicate with it.