Bursting pressure of triple-lumen central venous catheters under static and dynamic loads.

INTRODUCTION: Central venous catheter (CVC) access is commonplace in intensive care units. Patients undergoing computed tomographic angiography require injection of contrast at high flow rates (4.5 mL/s), often CVC access is not used due to safety concerns. The CVC might rupture at high flow rates, resulting in CVC fragmentation and embolization or contrast extravasation.The objective of this study is to determine the pressure required to burst a CVC under static load and compare this to the pressure generated by injection of contrast at high flow rates (dynamic load) through the distal (16-g) lumen of a triple-lumen CVC. METHODS: We gathered 16-cm long triple-lumen CVCs (n = 14) from patients with an average dwell time of 5.2 days (±2.7 days). Half the CVCs (n = 7) were subjected to static testing, where the distal lumen was occluded with the guidewire and super glue at the distal end of the catheter. The CVC was then placed into a 10-cm deep water bath at 37°C to simulate in vivo conditions and water was injected until catheter rupture. Dynamic pressure testing was done with the remaining catheters, with radio-contrast injected through the unoccluded distal lumen at flow rates of 4.5 mL/s, then 7 mL/s. Pressures were recorded throughout injection. RESULTS: During static testing, 6/7 CVCs burst at the distal lumen where the glue was applied, the remaining CVC burst proximal to the hub. PSI at burst during static testing was 184.2 PSI (95% confidence interval [CI] 174.3-194.1 PSI). During dynamic testing the mean peak pressures at 7 mL/s was 81.1 PSI (95% CI 73-89.2 PSI). At 4.5 mL/s the mean peak pressure was 47.9 PSI (95% CI 42.9-52.9 PSI). CONCLUSIONS: No CVCs failed under dynamic loading with injection of contrast at flow rates (4.5 and 7 mL/s) high enough to support computed tomographic angiography. This suggests 16-cm triple-lumen CVCs can be used safely.

Coronary artery fistula: a review.

Coronary arterial fistulas are abnormal connections between the coronary arteries and the chambers of the heart or major thoracic vessels. Although first described in 1841, the true incidence is difficult to evaluate because approximately half of the cases may be asymptomatic and clinically undetectable. This review will discuss the history and prevalence of coronary artery fistulas and their morphology, histology, presentation, diagnosis, treatment options, and complications.

Heinrich Obersteiner and his contributions.

Heinrich Obersteiner (1847-1921) was amongst the most influential neuroscientists in the 19th century. Born into a family of physicians, he gained early exposure to medicine, and as a medical student, he focused much of his research in neuroanatomy, eventually becoming a professor of neuroanatomy at the University of Vienna. Throughout his academic career, he focused greatly on neuropathology, and incorporated much of his research into his textbook, "Introduction to the Study of the Structure of the Central Nervous Organs in Health and Disease," which was considered the foremost reference text of neurology for many generations of scholars. The culmination of his contributions to the neurological world can be seen as the Neurological Institute of Vienna, which he founded in 1882. Scholars from all over the world sought out his expertize and tutelage. While he was the director of the Institute, over 500 articles were published within the Obersteiner-Arbeiten. Much of this work helped set the foundation for the eventual development of neurology as a medical discipline. A review of his life will help us better understand the legacy Heinrich Obersteiner left in the field of neurology.

Are pediatric brain tumors on the rise in the USA? Significant incidence and survival findings from the SEER database analysis.

INTRODUCTION: Central nervous system tumors are the second most common form of cancer in children between the ages of 1 and 19 years. We aimed to provide the most recent data on the incidence and survival of these tumors in the USA and to assess the literature. METHODS: Frequency, rates, and survival sessions were calculated using the November 2008 submission for the US Surveillance Epidemiology and End Results Program. Data were collected and analyzed for children and adolescents aged 1 to 19 years with primary brain tumors. RESULTS: We found that the incidence rate of all pediatric brain tumors has been on a gradual but steady increase from 1973 to 2008 (p < 0.001). The average annual increase was 1.37 %. Our survival analysis of the individual tumors revealed that the 5-year overall survival for children diagnosed between 1974 and 1978 with medulloblastoma was 43.7 %. However, this increased to 62.8 % for children diagnosed between 1999 and 2003. A similar survival trend was also observed when all the other pediatric brain cancer histologies were collectively analyzed (p < 0.001). CONCLUSIONS: From our study, we can conclude that contrary to previous reports indicating a plateau in the incidence rates of pediatric brain tumors since the mid-1980s, there has been an increase from 1973 to 2008. Potential causes include environmental carcinogens, but more research is needed to investigate the factors behind this sustained rise in incidence over the years.

Giovanni Domenico Santorini (1681-1737): a prominent physician and meticulous anatomist.

Venetian physician Giovanni Domenico Santorini is revered as one of the most industrious and thorough anatomists of the eighteenth century. After receiving his medical degree in Pisa, Santorini worked as a physician and professor of anatomy and obstetrics in Venice. Of interest, he was a student of Malpighi while in Pisa. He quickly established himself as a dynamic lecturer and meticulous dissector. Santorini's anatomical observations include the prostatic venous plexus, accessory pancreatic duct, corniculate cartilage, parietal emissary veins, the risorius muscle, and many other structures. In addition to the detailed descriptions of these structures, he also produced copper plates and illustrations that are revered as "masterpieces" of that era. Santorini published Observationes anatomicae (Anatomical observations) in 1724, however his primary work, which included the description and anatomical drawings of the accessory pancreatic duct, was not published until thirty-eight years after his death. This posthumous release of Jo. Dominici Santorini anatomici summi septedecim tabulae [Giovanni Domenici Santorini, the excellent anatomist's seventeen drawings] was accomplished by Giambattista Morgagni and his disciple, Michael Girardi in 1775. Giovanni Santorini's assiduous dissections have significantly enhanced our knowledge of human anatomy and his work has been immortalized with several anatomical eponyms.

Variations in the locations of the recurrent laryngeal nerve in relation to the ligament of Berry.

Injury to the recurrent laryngeal nerve (RLN) is one of the most common iatrogenic complications of thyroid surgery. The anatomical course of the nerve also increases its susceptibility to injury and many variations have been documented in the literature. The topographical relationship of the RLN to the ligament of Berry has been extensively studied over the past decades. The consensus in the literature is divided with several authors reporting the nerve to be embedded within the ligament and others reporting a constant finding of the nerve being posterolateral to the ligament. A new operative concept has been recently introduced as a possible resolution for the conflicting reports among authors. Further investigations are needed, however, to assess its reliability and overall effects on clinical outcomes.

Annular pancreas: a review of its molecular embryology, genetic basis and clinical considerations.

The annular pancreas remains an intriguing congenital anomaly. Many theories have sought to explain its embryological basis; however, no consensus has yet been reached regarding the exact mechanism of aberration. More recently, molecular investigations have shed light on some of these theories, confirming the origination of annular tissue from the ventral pancreatic bud. These studies highlight the role of the hedgehog signaling pathway in the development of this anomaly. Overexpression of the ventral-specific gene transmembrane 4 superfamily member 3 (tm4sf3) has also been associated with annular formation. Moreover, isolated case reports of familial annular pancreas have also been documented, suggesting a genetic basis for the development of this anomaly. Annular pancreas can initially present in childhood or adulthood with symptoms of duodenal obstruction and is diagnosed using a variety of imaging modalities. Treatment usually involves surgical correction, with bypass procedures (e.g. duodenoduodenostomy, gastrojejunostomy or duodenojejunostomy) currently favored over annular resection due to complications associated with the latter approach.