Clinical Utility Of Cavea2t2 Score For Assessing The Survival Of Brachiocephalic Arteriovenous Fistula.

BACKGROUND: There are not many error proof clinical scores to assess the native dialysis access. CAVeA2T2 score is a recent tool in use. Objective of the study is to assess the clinical utility of CAVeA2T2 scoring system in predicting the survival rate of brachiocephalic arteriovenous fistula (BC-AVF). METHODS: All consecutive patients fulfilling the inclusion criteria for BC-AVF from January 2016 to January 2018 were included. According to their CAVeA2T2 score they were divided into two groups (Group A: < 2 and Group B: ≥2). Cumulative primary and secondary patency survival of BC-AVF for both groups were measured. RESULTS: A total of 112 BC-AVFs were analysed. Mean age was 42±SD 14 years (M: F =5:1). Mean CAVeA2T2 score was 1.45±1.8. In terms of primary patency, there was no statistically significant difference between two groups (p=0.074, p = 0.229 and p=0.357 at 6 weeks, 6 months and 12 months respectively). However, the difference was significant in terms of secondary patency (p=0.002, p=0.036 and p=0.032 at 6 weeks, 6 months and 12 months respectively). On comparing the cumulative survival between two groups; a significantly low primary patency rate survival (Log Rank x2 = 12.9, p-value = 0.001) and secondary patency rate survival (Log Rank x2 = 7.6, p-value = 0.001) of BC-AVF was found in Group B. CONCLUSION: We found CAVeA2T2 score an easily applicable and useful tool to assess the patency and survival of BC-AVF. Patients have a poor patency and significantly low survival rate when their CAVeA2T2 score was ≥2.

A Retrospective Analysis of the Clinical Effectiveness of Supraclavicular, Ultrasound-guided Brachiocephalic Vein Cannulations in Preterm Infants.

BACKGROUND: The aim of this retrospective analysis was to evaluate the clinical effectiveness of the supraclavicular ultrasound-guided cannulation of the brachiocephalic vein in preterm infants. METHODS: The ultrasound probe was placed in the supraclavicular region so as to obtain the optimum sonographic long-axis view of the brachiocephalic vein. By using a strict in-plane approach the brachiocephalic vein was cannulated by advancing a 22- or 24-gauge iv cannula from lateral to medial under the long axis of the ultrasound probe under real-time ultrasound guidance into the vein. RESULTS: One hundred and forty-two cannulations in infants weighing between 0.59 and 2.5 kg (median: 2.1; CI: 2.0 to 2.2) were included. Ultimate success rate was 94% (134 of 142). One cannulation attempt was required in 100 (70%) patients, two attempts in 21 (15%), and three attempts in 13 (9%). The smaller the weight of the infant the more attempts were needed. More attempts also were needed for the right brachiocephalic vein, which was primarily targeted in 75 (53%) neonates. One (1%) inadvertent arterial puncture was noted. CONCLUSIONS: This supraclavicular, in-plane, real-time, ultrasound-guided cannulation of the brachiocephalic vein seems to be a convenient and effective method to insert central venous catheters in preterm infants.

Anomalous left brachiocephalic vein: important vascular anomaly concomitant with congenital anomalies and heart diseases.

BACKGROUND: Anomalous left brachiocephalic vein (ALBCV) is a rare and less known systemic venous anomaly. Infrequently, this vein takes an abnormal course and passes to the right behind or beneath the aortic arch to create the superior vena cava (SVC). Its incidence was reported much higher in patients with congenital heart disease especially in conotruncal and aortic arch anomalies. It could be misdiagnosed with normal or abnormal mediastinal structures. It also could make complication during surgeries or invasive strategies. Previously, this anatomical finding has been reported in case reports and there are just few studies evaluating these patients as a group to find other abnormalities MATERIALS AND METHODS: We conducted a retrospective, multicentre study between 2008 and 2014 at three institutions. We reviewed thoracic computed tomography angiography of 1372 patients referred to these centres. The diagnosis of ALBCV was confirmed by an expert radiologist and the imagings were reassessed to identify new cases and concomitant anomalies. We analysed the imagings' details and measured the prevalence of each anomaly. RESULTS: Among the 22 cases of ALBCV, 12 (54.5%) and 10 (45.4%) patients were males and females, respectively, with median age of 12.5 years. Tetralogy of Fallot (TOF) was considered as a most concomitant anomaly with ALBCV (54.5%). Two patients had associated atrial septal defect (ASD) and defined as pentalogy of Fallot. Right-sided aortic arc (RSAA) was detected in 12 (54.5%) patients; mirror image was found in 5 of them. Pure ventricular septal defect or pulmonary stenosis without TOF was recognised in 4 patients. Three cases had isolated overriding aorta (13.6%). In 3 patients, we could find patent ductus arteriosus (13.6%). In 2 (9%) patients, abdominal haemangioma was incidentally diagnosed. Aberrant left retrotracheal subclavian artery was detected in 1 (4.5%) patient. One patient only had isolated ALBCV (4.5%). CONCLUSIONS: In our study, ALBCV was frequently seen in association with other congenital anomalies. mostly TOF and RSAA. In patients with pulmonary hypoplasia or aplasia, some parts of lung's blood supply were provided by abnormal aorto-pulmonary connections. For a radiologist, it is important to differentiate this anomaly in cross-sectional imaging from persistent left SVC, partial anomalous pulmonary veins return and an enlarged lymph node. Detection of ALBCV could draw the attention to the more serious heart disease and in isolated forms prevented further evaluations.

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.

A scoring system (DISTAL) for predicting failure of snuffbox arteriovenous fistulas.

OBJECTIVES: A first fistula failing will lead to serious morbidity in a proportion of patients. Snuffbox fistulas have the advantage of proximal vessel preservation, and although several factors have been associated with failure, the relative importance of these factors combined and their clinical applicability is unknown. The aim of this study was to determine the relative importance of risk factors for snuffbox fistula failure and create a simple scoring system to aid fistula placement decision making. METHODS: 218 consecutive patients were examined using Cox regression analysis to determine risk factors for failure. Primary patency was used as the endpoint. RESULTS: Diabetes, IHD, Stroke, Two snuffbox procedures, Age > 70 and Less than 2.0 mm vein (DISTAL, maximum score 6) were significant predictors of primary patency failure. There was a clear decrease in primary patency with increasing DISTAL score (log rank χ(2) = 30.3, DF = 5, P < 0.001). Performing snuffbox procedures on patients with a score ≤ 3 would give a 23% reduction in the number of failures within two months for a 12% reduction in the number of patients offered snuffbox procedures. CONCLUSION: The DISTAL scoring system could give large improvements in primary patency for the snuffbox fistula if the results can be validated in other datasets.

Influence of muscle training on resting blood flow and forearm vessel diameter in patients with chronic renal failure.

BACKGROUND: Blood flow and vessel diameter are predictors of the success of vascular access procedures. This study investigated whether a simple exercise programme could influence these variables. METHODS: Twenty-three patients with chronic kidney disease were prescribed a simple exercise programme for one arm only; the investigators were blinded to the patients' choice. All underwent arterial and venous duplex imaging, handgrip strength and blood pressure measurements before and 1 month after the exercise programme. RESULTS: Twelve patients exercised their dominant and 11 their non-dominant arm. In the trained arm, the exercise programme resulted in a significant increase in handgrip strength, by a median (interquartile range) of 4 (0-8) kg (P < 0.001), and in the diameter of the brachial artery (0.2 (0.1-0.3) mm; P < 0.001), radial artery (0.3 (0.2-0.4) mm; P < 0.001), and cephalic vein (0.6 (0.4-1.2) mm in the forearm and 1.1 (0.4-1.2) mm above the elbow; P < 0.001). There was an increase in brachial artery mean velocity (3 (1-7) cm/s; P = 0.009) and peak systolic velocity (8 (1-15) cm/s; P = 0.020), despite a marginally lower systolic blood pressure (-8 (-16 to 0) mmHg; P = 0.007). There was no change in any of these parameters in the non-exercised arm. CONCLUSION: In patients with chronic kidney disease, forearm exercise increased blood flow and vessel diameters. This may be beneficial before vascular access formation.

On the phenomenology of the perforating vein of the elbow.

The perforating veins, as the name suggests, are the veins that perforate the muscular aponeuroses ensuring communication between the superficial and the deep veins. Located at the bend of the elbow, almost constantly, there is a vein, named perforating vein of the elbow, which is of great interest to the nephrologist who is responsible for the management of vascular access for hemodialysis (HD). It represents, in fact, because of its intrinsic characteristics and topographical reasons, a valuable resource for the creation of a vascular access for HD, especially in obese patients, elderly patients, diabetics, and patients affected by peripheral vasculopathy. Arterio-venous fistulae (AVF) constructed with the perforating vein of the elbow are relatively easy to perform, have an excellent patency rate, a low incidence of early thrombosis, adequate flows, and a low incidence of the steal syndrome. In other types of AVFs, the perforating vein of the elbow subtracts flow to the superficial veins slowing or preventing their full maturation, and can become a problem in measuring the blood flow of the AVF. But still, its presence can maintain patent a fistula in case of poor compliance of the superficial veins, while awaiting for interventional procedures able to accelerate a subsequent maturation. This review intends to explore the role that the perforating vein of the elbow plays in the physiology and pathology of the AVF, in relation to the issues that most frequently occur in clinical practice.

Venas superficiales de la fosa cubital: aspectos anátomo-clínicos y antropológicos / Superficial veins of the cubital fossa: anatomo-clinic and anthropologic aspects

Es bastante frecuente el acceso a las venas superficiales de la fosa cubital, siendo uno de los sitios más utilizados para punción venosa. Aunque es un procedimiento simple, es invasivo y a veces doloroso. La disposición de las venas superficiales de la región cubital ha sido descrita por numerosos autores y en diversos grupos étnicos, describiéndose variaciones y diversas padronizaciones. Las venas superficiales de la fosa cubital se han descrito formando una M, N, Y y W. Numerosos estudios, en distintas razas y grupos étnicos han demostrado similitudes y diferencias en la disposición de las venas superficiales de la fosa cubital. En 1908 Berry & Newton determinaron que en el 83% de los hombres británicos la vena cefálica del antebrazo (VCA) y la vena basílica del antebrazo (VB A) eran conectadas por la vena mediana del codo (VMCo). Okamoto (1922) en hombres japoneses, determinó 3 Tipos de padrones venosos: Tipo I donde la VCA origina la VMCo, no existe la vena cefálica accesoria del antebrazo (VCAA), y la VCA no se duplica; Tipo II, caracterizado por la duplicación de la VCA y un Tipo III, que incluye la VCAA que drena en la VCA. En hombres blancos y negros Charles (1932) señaló que la distribución más frecuente (cerca de 70% de los casos), era aquella donde la VCA y la VB A eran conectadas por la VMCo. Soller et al. (1962, 1964) en africanos de África Occidental, distinguieron tres tipos de formaciones venosas. Grupo I. Disposición clásica, tipos en M o aparentes (38,1%). Grupos II y III descritas como disposiciones de tipo embrionario constituyen el 62% de los casos. Halim & Abdi (1974) en hindúes, observaron tres tipos: 1) Tipo I. La VCA y la VBA son conectadas por la VMCo; Tipo II. La VCA drena en la VBA; la vena mediana del antebrazo (VMA) drena en la VCA. Tipo III. No existe comunicación entre la VCA y la VBA en la fosa cubital y la subdividen en Tipos IIIA y III B. Wasfi et al. (1986) describieron ...

Access of the cubital fossa to the superficial veins is very frequent, this being one of the most frequent vein puncture sites. Although it is a simple procedure, it is invasive and at times painful. The disposition of the superficial veins of the cubital area has been described by numerous authors and in diverse ethnic groups, describing many variations and various patterning. The superficial veins of the cubital fossa have been independently described, forming an M, N, Y or W. Numerous studies in different races and ethnic groups have demonstrated similarities and differences in the disposition of the superficial veins of the cubital fossa. In 1908 Berry & Newton determined that in 83% of British men the cephalic vein of the forearm (CVF) and the basilic vein of the forearm (BVF) were connected by the median cubital vein (MCV) Okamoto (1922) in Japanese men, determined 3 types of venous patterns. Type I where the CVF originates the MCV, the accessory cephalic vein (ACV) does not exist, and the (CVF) does not duplicate; Type II is characterized by the duplication of the CVF and a Type III, that includes the ACV which drains in the CVF. In white and black men Charles (1932) indicated that the most frequent distribution (nearly 70% of the cases), was that where the CVF and the BFV were connected by the MCV. Soller et al. (1962, 1964) in Africans from West Africa, distinguished three types of venous formations. Group I classic dispositions, types in M or apparent (38.1%) Groups II and III described as dispositions of the embryological type constitute 62% of the cases. Halim & Abdi (1974) observed 3 types in Hindus types: 1) Type I. The CVF and the BVF are connected by the MCV; Type II. The CVF drains in the BVF: the median vein of the forearm (MVF) drains in the CVF. Type III. There is no communication between the CVF and the BFV in the cubital fossa and it is subdivided in Types III A and III B. Wasfi et al. (1986) described ...

Brachial vein transposition arteriovenous fistula: is it an acceptable option for chronic dialysis vascular access?

PURPOSE: The aim of this study was to evaluate the midterm performance of brachial vein arteriovenous fistulas (AVFs) and to compare this performance with arteriovenous grafts (AVGs) and basilic vein transposition AVFs. METHODS: A retrospective analysis was performed. Between December 2002 and October 2006, 149 AV access procedures consisting of brachial vein transposition AVFs (11 one-stage and 2 two-stage procedures), basilic vein transposition AVFs (n=42), and AVGs (n=94) were performed in 141 patients. RESULTS: 73% of one-stage brachial vein AVF patients experienced at least one complication during follow-up vs. 52% of the basilic vein transposition AVF group and 55% of the AVG group. The primary patency rates at 12 months for one-stage brachial vein AVFs, basilic vein AVFs, and AVGs were 24, 45 and 50%, respectively. The assisted primary patency rates were 45, 74 and 63%, and the secondary patency rates were 45, 74 and 78%, respectively. A significant difference in the overall secondary patency rates between one-stage brachial vein AVF and AVGs (p=0.015) was detected. Significance was approached between one-stage brachial vein AVFs and basilic vein AVFs overall assisted primary patency (p=0.055) and secondary patency (p=0.055) rates. CONCLUSION: The brachial vein transposition, when done as a one-stage procedure, is associated with inferior patency rates when compared to the basilic vein transposition AVF and AVG. Therefore, in the setting of inadequate cephalic and basilic vein, a prosthetic graft is superior to a brachial vein transposition. A two-stage procedure, as suggested by others, may improve the results of this technique.

Changes in blood flow in conduit artery and veins of the upper arm during leg exercise in humans.

This study investigated changes in blood flow in the conduit artery, superficial vein, and deep vein of the upper arm during increase in internal temperature due to leg cycling. Additionally, we sought to demonstrate the contributions of blood velocity and vessel diameter on blood flow responses. Fourteen subjects performed supine cycling exercise at 60-69% maximal oxygen uptake for 30 min at an ambient temperature of 28 degrees C and relative humidity of 50%. Blood velocity and diameter in the brachial artery, basilic vein (superficial vein), and brachial vein (deep vein) were measured using ultrasound Doppler, and blood flow was calculated. Blood flow in the artery and superficial vein increased linearly with rising oesophageal temperature (DeltaT (oes)) after DeltaT (oes) was about 0.3 degrees C (within threshold), as well as cutaneous vascular conductance on the forearm. Changes in blood velocity in these vessels were similar to those in blood flow. Conversely, the brachial artery and superficial vein diameter did not affect the blood flow response. Blood flow variables in the deep vein did not change remarkably with rising DeltaT (oes). These results suggest that blood flow response, by an increase in velocity, in the conduit artery with rising DeltaT (oes) during exercise is similar to that in the superficial vein, but not deep vein. Also, it is indicated that these increases in blood flow relate to the increase in skin blood flow on the forearm with the rise in body temperature during exercise.

Does the surgeon's experience impact on radiocephalic fistula patency rates?

Establishing successful long-term hemodialysis access remains a major challenge. The primary aims of this study were to determine whether primary success and primary and secondary patency rates of a series of consecutive radio-cephalic fistulae (RCF) were affected by the experience of the surgeon. The secondary aims were to assess complications, and to compare results with patency rates from the literature. All native fistulae (AVF) created in our unit between January 1, 2002 and December 31, 2005 were analyzed retrospectively. The RCF were identified and divided into group A (RCF fashioned by the consultant surgeon), and group B (fashioned by the junior surgeons within the unit). Demographic characteristics, risk factors, primary success rate (patent fistula at discharge), and primary and secondary patency rates were compared between each group using chi-squared test. During this period, 552 AVF were created. Of the 195 RCF, there were 153 fistulae in group A and 42 in group B. Median follow-up was 22 months for both groups. There was no difference with regards to age, sex ratio, prevalence of diabetes, and cardiovascular disease. The primary success rate in group A and B was 94.2% and 81%, respectively (p < 0.01). Primary and secondary patency rates at 22 months were 80%, 93%* and 74%, 81%* in group A and B, respectively (*p < 0.025). Even within group B, these results compare very favorably with the published literature. These results suggest that the placement of a RCF should be performed by the most experienced member of a team dedicated to vascular access creation or at least under his supervision.

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.

Within-session and between-session variability of haemodialysis shunt flow measurements.

BACKGROUND: Knowledge of the variability of a measurement method is essential for its clinical application. We investigated the variability of shunt flow measurements, since this is a relatively neglected area in the literature. In particular, no direct comparison of between-session and within-session variability was available until now. METHODS: During two consecutive dialysis sessions, shunt flow was measured three times with the ultrasound dilution method in 24 chronic haemodialysis patients with various types of shunts. Needle orientation and blood pressure at the time of flow measurement were recorded. In these patients, shunt flow was also measured three times by duplex ultrasound before the first dialysis session. RESULTS: The within-session variation coefficient (VC) of shunt flow measured with ultrasound dilution was 7.7%, whereas the between-session VC was 14.2% (n.s.). The within-session VC of Doppler shunt flow was 11.6% which was not significantly different from the corresponding figure of ultrasound dilution. Analysis of subgroups showed that changes in needle orientation caused large differences between sessions in radiocephalic fistulas but not in brachiocephalic fistulas: in the radiocephalic fistulas with the same needle orientation, VC was 6.7%, but with different needle orientation it was 23.5% (P = 0.02); the corresponding figures for brachiocephalic fistulas were 14.6% (same direction) and 11.4% (different direction, n.s.). CONCLUSION: Reproducibility of shunt flow measurements between dialysis sessions in radiocephalic fistulas is critically dependent on similar needle orientation. With similar needle position and correction for blood pressure differences, flow changes of more than 20-25% are likely to reflect true flow changes. The variability of duplex flow measurements is at least as large as that of the ultrasound dilution method.

An anatomical study of the partial anomalous pulmonary venous return with special references to the bronchial vein.

Two examples of partial anomalous drainage of the pulmonary vein were detected at dissection. The first case was found in a 70-year-old female Japanese. An aberrant vein, approximately 6 mm in diameter, that derived from the upper lobe of the right lung was observed to drain into the superior vena cava at a point just below the entrance of the azygos vein. The other veins from the right lung gathered into two pulmonary veins and returned into the left atrium as usual. In the second case, which was found in an 80-year-old female Japanese, a connecting vein, approximately 8 mm in diameter, was found between the left superior pulmonary vein and the left brachiocephalic vein. In this case, although the direction of the blood flow within the connecting vein was not certain, it is probable that the blood passed from the pulmonary vein into the brachiocephalic vein, judging from the increase in the width of the latter vein. No other anomalies were found in the cardiovascular systems. At the occurrence of the anomalous drainage of the pulmonary veins in both cases, we suspected the role of the bronchial vein to be a communicating and boundary vein between the pulmonary and systemic circulations. The developmental background of these anomalies is also considered.

Volume flow measurement in hemodialysis shunts using time-domain correlation.

Volume flow was measured in 58 hemodialysis shunts (32 grafts and 26 radial fistulas) using the color velocity imaging-quantification method. This method is based on time-domain correlation for velocity calculation and integration of time-varying velocity profiles generated by M-mode sampling. Measurements were made in the brachial artery to estimate radial fistula flow or directly in the grafts. Intraoperator reproducibility was 14.9% for fistulas and 11.6% for grafts. Flow rate was significantly lower in abnormal shunts associated with a functional disorder or a morphologic complication (808 ml/min +/- 484) than in shunts associated with no abnormalities (1401 ml/min +/- 562). Receiver operating characteristic curves showed that a flow rate of 900 ml/min for fistulas and 1300 ml/min for grafts provided 81% and 79% sensitivity and 79% and 67% specificity, respectively. A functional disorder or a morphologic complication was associated with all fistulas and grafts in which flow rates were lower than 500 ml/min and 800 ml/min, respectively.

Partial agenesis of the azygos vein: a case report.

In the cadaver of an 86 year old man the inferior segment of the azygos vein could not be found. Furthermore, a normally developed hemiazygos vein drained the right and left intercostal veins from T 10 to T 6. This vessel finally curved towards the right to reach the superior vena cava after having drained the right superior intercostal veins. The left superior intercostal vein ended in a short vessel draining into the left brachiocephalic vein. This condition may be represented in a standard chest radiograph by the so-called "aortic nipple". Agenesis of the azygos vein, suspected because of the presence of this radiological sign, should be confirmed in the living by means of computerized tomography. This can clarify the anatomy of the mediastinal vessels precisely. Embryological pattern of the azygos system accounting for its possible defects is discussed.

Hemodynamic and cerebral repercussions arising from surgical interruption of the superior vena cava. Experimental model.

This study was designed to analyze the hemodynamic and cerebral repercussions arising from the surgical interruption of the superior vena cava. The experiments were carried out in 12 mongrel dogs under two different conditions: with shunt (group A, n = 6) and without the installation of a shunt (group B, n = 6). The period of occlusion was 35 minutes. The right atrium pressure, pulmonary arterial pressure, and aortic pressure are not significantly modified in the two groups. The intracranial pressure had an important correlation with the central venous pressure (r2 = 0.8572). In group B, the intracranial pressure had a sharp increase between the basal period (6.9 +/- 1.47 mm Hg) and the clamping superior vena cava (17.2 +/- 1.05 mm Hg), accentuated with the interruption of the azygous vein (32.2 +/- 0.7 mm Hg). In group A, the use of a shunt avoided this alteration during clamping of the superior vena cava (6.8 +/- 2.0 mm Hg) and the azygous vein (8.0 +/- 2.24 mm Hg). However, after removal of the clamps in group B, an elevated residual intracranial pressure was observed (21.1 +/- 3.33 mm Hg) in contrast to the central venous pressure, which returned to the basal values (4.4 +/- 0.7 mm Hg). The biomechanic findings of the volume-pressure curves (with Miller and Marmarou-Shapiro tests) and the cerebral necropsy showed brain damage in group B, without the shunt. Three animals had areas of hemorrhagic infarction. Histologic study demonstrated signs the incipient vasogenic edema. In group A, all findings were compatible with the normal. In conclusion, these results suggest the importance of shunting the blood in those cases of a nonobstructed superior vena cava because the clamping and reconstruction produce hemodynamic compromise and brain damage.

A macroscopic study of the internal thoracic artery of the rat.

The internal thoracic artery (ATI) of rats was macroscopically studied. In this study, the overall features of the artery were virtually elucidated in entirety. The artery was found to arise from the subclavian artery in the thoracic cavity and to immediately break up into the following branches: (1) the pericardiacophrenic artery, (2) the superior epigastric artery, (3) the thymic branch, (4) the comitans branch to the brachiocephalic veins, and finally (5) the bronchoesophageal trunk. As is well known, rats are devoid of the superior caval veins, retaining instead a pair of brachiocephalic veins into adulthood; this is a greatly beneficial condition as it enables us to consider the essential relationships of the ATI to relevant structures which are thought to be directly involved in the development of the ATI. In fact, the rat ATI revealed topographically a remarkable intimacy with the phrenic nerve, the brachiocephalic and inferior caval veins, the heart and lungs and also with the diaphragm; in their development all are in close relationship with the pleuropericardial fold. This fact leads us to the opinion that, for a better understanding of the morphological meanings of the ATI, an understanding of the relationship of this artery to the pleuropericardial fold seems to be a prerequisite.

Percutaneous cervical central venous line placement: a comparison of the internal and external jugular vein routes.

To compare the rate of success and incidence of complications associated with two currently popular routes of percutaneous central venous cannulation, we studied 167 patient in whom either internal or external jugular vein catheterization was attempted. Internal jugular vein (IJV) catheterization (125 patients) was successful in 91%; an intrathoracic location was achieved in 100%; complications occurred in 12.8%. Complications included one case of catheter malposition, one case of tension pneumothorax, and 12 instances of inadvertent carotid artery puncture, one resulting in a paratracheal hematoma and phrenic nerve compression. The success rate of IJV cannulation was higher and carotid artery puncture less frequent when an 18-gauge thin-walled needle and a straight guide-wire were used than when IJV cannulation was performed by bind puncture with a larger over-the-needle catheter. Delayed vein perforation occurred twice. External jugular vein cannulation (42 patients), using a "J" wire technique, yielded a 76% success rate: 93.7% of catheter tips reached an intrathoracic location. No complications occurred. We conclude that IJV cannulation is a more reliable means of percutaneous central venous line placement but is associated with a significant incidence of complications which can be reduced if a technique employing a scout needle and guide-wire is used.