Patency of neck veins following ultrasound-guided percutaneous Hickman line insertion.

PURPOSE: Venous occlusion following permanent central venous catheter (CVC) insertion by open cutdown or the landmark percutaneous technique has been reported between up to 25 %. However, there are no published data on the equivalent rate following ultrasound-guided percutaneous CVC insertion. The purpose of this study was to document the rate of venous occlusion associated with ultrasound-guided percutaneous CVC insertion in children. METHOD: From 1 April 2010 to 1 December 2011, all children having elective or emergency removal of a Hickman line by the vascular access team had a Doppler ultrasound of their neck veins. Only Hickman lines inserted by the ultrasound-guided percutaneous route were included. Internal jugular, innominate and subclavian veins were scanned and recorded as patent, reduced or absent. RESULTS: We identified 100 consecutive children. Median age was 6 years (range 21 days to 16 years). Indication for insertion was chemotherapy (60), parenteral nutrition (15), blood products (12), renal replacement (3) and other indications (10). Three children had absent flow at the time of line removal (median age 4 months, range 3-6 months), with 2 out of 3 requiring removal for infection. The venous occlusion rate following ultrasound-guided insertion of CVC is 3 % in our study. CONCLUSIONS: We conclude that (1) complete venous occlusion is associated with younger age and CVC infection. (2) In our study, the venous occlusion rate of 3 % is significantly lower than the published series of either open cutdown or the landmark technique.

Ultrasound-guided percutaneous insertion of 2.7 Fr tunnelled Broviac lines in neonates and small infants.

BACKGROUND/PURPOSE: Insertion of permanent central venous access (Broviac line) can be a challenge in neonates especially when sites for peripherally inserted central catheters (PICC) have been exhausted. The landmark technique (LT) has been well described for the percutaneous insertion of central lines in neonates but can be associated with significant complications including death. The use of the ultrasound-guided approach for temporary central line access has been reported but as yet there are no reports of the adaptation of the technique for Broviac line insertion in neonates. METHOD: A prospective database records all procedures carried out by the vascular access team and any complications which occur; this database was reviewed from November 2004 to January 2008. RESULTS: A consecutive series of 34 neonates underwent insertion of 36 Broviac lines using the ultrasound-guided percutaneous technique with a 2.7 Fr silastic line and a 3 Fr peel-apart sheath. Median gestational age was 34 weeks (range 24-40), chronological age was 102 days (14-209 days), weight 2.9 kg (0.63-4.1). Successful cannulation occurred in 100% of patients. There were no cases of arterial puncture or perioperative complications due to surgery. CONCLUSION: The ultrasound-guided percutaneous approach for insertion of tunnelled permanent vascular access is safe in neonates with no surgical complications in our series. However, it is a technically demanding procedure to do in neonates and should not be attempted without significant prior experience.

Anaesthetic outcome and predictive risk factors in children with mediastinal tumours.

PURPOSE: The aims were to identify and test the significance of specific factors associated with risks for anaesthesia in children with mediastinal tumours. PATIENTS AND METHOD: Clinical information was retrospectively collected from the records of 63 children presented with mediastinal tumour (1964-2002) in a regional Paediatric Oncology centre and correlated with the type and outcome of anaesthesia, using non-parametric analyses. RESULTS: Thirteen patients had local anaesthesia or sedation for diagnostic procedures and none developed any complication. Fifty children received general anaesthesia (GA) for diagnostic investigations or tumour resection. Two patients were excluded from the analysis because of treatment prior to GA. Problems with intubation, ventilation and cardiovascular collapse were encountered in 7 of 48 (15%) patients and this resulted in tracheostomy in one patient and death in 2 other cases. When compared with the 41 uncomplicated cases, the presence of at least 3 respiratory symptoms/signs, tracheal and vascular compression, and infection significantly increased the risk of GA. Of these, tracheal compression remained the strongest predictive factor. CONCLUSIONS: Decision to postpone GA should be considered if all these risk factors (tracheal compression, vascular compression, the presence of at least three respiratory symptoms/signs) are present in the same patient.

Management of end-stage central venous access in children referred for possible small bowel transplantation.

UNLABELLED: The 3-year survival after small bowel transplantation (SBTx) has improved to between 73% and 88%. Impaired venous access for parenteral nutrition can be an indication for SBTx in children with chronic intestinal failure. AIM: To report our experience in management of children with extreme end-stage venous access. SUBJECTS: The study consisted of 6 children (all boys), median age of assessment 27 months (range, 13-52 months), diagnosed with total intestinal aganglionosis (1), protracted diarrhea (1), and short bowel syndrome (4), of which gastroschisis (2) and malrotation with midgut volvulus (2) were the causes. All had a documented history of more than 10 central venous catheter insertions previously. All had venograms, and 1 child additionally had a magnetic resonance angiogram to evaluate venous access. Five of 6 presented with thrombosis of the superior vena cava (SVC) and/or inferior vena cava. METHODS: Venous access was reestablished as follows: transhepatic venous catheters (5), direct intra-atrial catheter via midline sternotomy (4), azygous venous catheters (2), dilatation of left subclavian vein after passage of a guide wire and then placing a catheter to reach the right atrium (1), radiological recanalization of the SVC and placement of a central venous catheter in situ (1), and direct puncture of SVC stump(1). Complications included serous pleural effusion after direct intra-atrial line insertion, which resolved after chest drain insertion (1), displacement of transhepatic catheter needing repositioning (2), and SVC stent narrowing requiring repeated balloon dilatation. OUTCOME: Four children with permanent intestinal failure on assessment were offered SBTx, 3 of which were transplanted and were established on full enteral nutrition; the family of 1 child declined the procedure. In the remaining 2 children in whom bowel adaptation was still a possibility, attempts were made to provide adequate central venous access as feeds and drug manipulations were undertaken. One of them received liver and SBTx nearly 3 years after presenting with end-stage central venous access, because attempts to achieve independence from parenteral nutrition had failed. The other child died immediately after a transhepatic venous catheter placement, possibly from a nutritional depletion syndrome as no physical cause of death was found. Direct intra-atrial catheters in transplanted children proved to be adequate for the management of uncomplicated transplantation, although the usual infusion protocol had to be modified considerably, and the lack of access would have been critical if massive blood transfusion had been required during the transplant procedure. CONCLUSION: It was possible to reestablish central venous access in all cases. However, this was time consuming and difficult to assemble a skilled team consisting of one of more: surgeon, cardiologist, interventional radiologist, and transplant anesthetist. Small bowel transplantation is easier and safer with adequate central venous access, and we advocate liaison with an SBTx center at an early stage.

Validity and reliability of selected commercially available metabolic analyzer systems.

Automated metabolic gas analysis systems have advanced considerably over the past decade. They provide an abundance of information, which is not possible by using the traditional Douglas bag method and have become an essential tool in both physiological monitoring and in the diagnosis of cardiopulmonary disease. The validity and reliability of the different online metabolic analyzer systems are not well known, with relatively few independent studies being published. The purpose of this review was to examine and evaluate current literature regarding the validity and reliability of commercially available metabolic analyzer systems. This review reveals significant differences between the available systems in the way that they capture and process basic respiratory measurements. Online metabolic analyzer systems were found to vary significantly when compared with Douglas bag methods. These variations have the potential to introduce error into the accuracy with which the health of cardiovascular system can be assessed or training loads can be assigned. Compounding this is the fact that many automated systems are a "black box", which makes it easy to generate data without the user having much understanding of how the data were generated. In conclusion automated metabolic analyser systems are a scientifically robust method for the evaluation of cardiopulmonary function. Individual researchers and clinicians must, however, be able to make their own decisions about the level of error that is tolerable for their individual needs. This presents a significant practical challenge in light of the speed with which technical developments in the field occur and we make some suggestions for the formulation of intersystem comparison studies.

Delayed onset refractory dystonic movements following propofol anesthesia.

Neuroexcitation is an uncommon but well recognized side effect of propofol anesthesia and sedation. We present a patient who, despite an intact mental status and without any preexisting movement disorder, experienced delayed onset of involuntary dystonic movements involving head, neck and shoulder for 11 h following emergence from propofol/nitrous oxide anesthesia.

Agreement between three commercially available instruments for measuring short-term heart rate variability.

Numerous instruments are commercially available to measure heart rate variability, yet little is known regarding the agreement between such instruments. The objective of this study is to assess agreement between measures of heart rate variability in three commercially available instruments. Thirty subjects (20 males) of median age 27.5 (range 19-59 years) underwent simultaneous ECG recordings, under three different resting conditions: supine, standing and supine with controlled breathing, using three commercially available analysers. Intraclass correlation coefficients tended to show excellent agreement (lower 95% C.I., R > 0.75) between all instruments under all conditions. However, further analysis of selected measurements using the limits of agreement method revealed large variation in values generated by all instruments. There was also an evidence of systematic bias between one instrument and the remaining two. The latter finding was due to discrepant ECG recording protocols that were unrelated to consistent operator timing. This study demonstrates that measures of HRV generated by the three instruments did not agree well in all cases. Discrepancies were due to the recording protocols of the systems. This may lead to incomparable results between instruments. It is therefore recommended that: (a) if different instruments are used in the same study or (b) multi-centre study designs are planned or (c) heart rate variability results are discussed with reference to studies using other instruments, levels of agreement need to be reported to ensure comparability.

Reliability of three commercially available heart rate variability instruments using short-term (5-min) recordings.

AIM: To assess the reliability of heart rate variability (HRV) measures made by three commercially available analysers in healthy subjects. METHODS: Twenty-nine volunteers (20 males, mean age 35 +/- 13 years and nine females, mean age 29 +/- 11 years) underwent repeated HRV measures under three conditions: lying supine, standing, lying supine with controlled breathing. HRV was measured simultaneously by three instruments. Reliability was assessed statistically by calculating coefficient of variation (CV), intraclass correlation coefficient (ICC) and limits of agreement (LoA). RESULTS: A wide range of values were found for CV (1-235%) and ICC (R = 0.16-0.99) dependent on the HRV measure assessed and the position in which the measurement was made. For the most part the analysers gave similar values in each condition. The values for CV and ICC were high but within the range reported in the literature. Values for LoA were also high and showed a wide range of values. CONCLUSIONS: The similarity in measures between systems indicates that biological variation and experimental error play a major role in determining the repeatability of HRV measurements. It is therefore recommended that population-specific reliability coefficients should be published where possible and that authors should take into account the reliability of measures when making sample size calculations.

Lessons from the wild turkey.

Fifty years ago, the American wild turkey survived in isolated, small populations. Now an estimated 5.6 million birds are spread across the continental United States (minus Alaska) and Ontario, Canada.

Complete inhibition of intimal hyperplasia by perivascular delivery of paclitaxel in balloon-injured rat carotid arteries.

PURPOSE: To determine whether perivascular delivery of paclitaxel prevents luminal narrowing after balloon injury by inhibiting intimal hyperplasia. MATERIALS AND METHODS: Immediately after balloon injury of the entire left common carotid artery, three slow-release formulations of paclitaxel or control formulations without drug were applied around a distal segment of the artery. The noninjured right carotid arteries were evaluated as a control. The animals were maintained for 14 and 28 days (n = 5 in each group at each time interval). Histology, immunohistochemistry, and morphometric analysis were performed. RESULTS: Injured nontreated arteries exhibited a pronounced intimal hyperplasia (0.185 +/- 0.01 mm2 at 14 days and 0.189 +/- 0.01 mm2 at 28 days) and a marked reduction in luminal area (44% at 14 days and 43% at 28 days). Medial area and the number of medial cells increased by 44% and 45%, respectively, at 14 days, and by 22% and 37%, respectively, at 28 days. Injured arteries treated with perivascular paclitaxel did not show any intimal hyperplasia, and luminal area was increased in five of six groups and was unchanged in one group. These arteries had an increased medial area but they had fewer medial cells than noninjured arteries. Injured arteries treated with control implants without paclitaxel exhibited intimal hyperplasia and luminal narrowing. CONCLUSION: Perivascular slow release of paclitaxel totally inhibits intimal hyperplasia and prevents luminal narrowing after balloon injury. Because of its efficacy, perivascular paclitaxel represents a possible approach for prevention of restenosis in humans.

Abdominal aortic aneurysms before and after endograft implantation: evaluation by computed tomography.

The evaluation of patients with abdominal aortic aneurysms for endograft candidacy and their follow-up after treatment are heavily dependent on radiologic imaging. Factors never considered during conventional open repair have become crucial to patient selection and procedural success, and the new and developing nature of the field of endovascular repair necessitates close surveillance of these devices after deployment. Computed tomography (CT) has emerged as the single most effective imaging tool for the preprocedural assessment and subsequent follow-up of these patients. This article outlines the technical parameters for obtaining pre- and postoperative CT examinations in endograft patients and discusses the important imaging findings.

Giving something back.

The Taoist teachings of self-reflection, openness, and sharing of self illustrate the need for the seasoned professional to examine one's own practice and share with the greater professional community. Taoism incorporates interdependency and harmony for all systems and suggests that as individuals we rely on the well-being of the whole. Four specific methods provide meaningful ways to give back to the profession; networking, presenting, publishing, and professional association work. Implementing one or more of these methods promotes the profession's collegial spirit and facilitates one's own growth while giving to others.