Thrombosis associated with right internal jugular central venous catheters: A prospective observational study

Background and Aims:

Central venous catheters (CVC) are essential in a critical care setting. Thrombosis is one of the very important associated complications that can lead to increased morbidity and mortality. The aim of this study was to find out the incidence of thrombosis in right-sided internal jugular vein (IJV) CVC with the help of color Doppler duplex sonography, its extent, risk factors and clinical impact.

Materials and Methods:

One hundred consecutive patients having right-sided IJV CVC were included in the study. Color Doppler sonography was performed on the 3^rd and 6^th days after CVC insertion. The size of the thrombus was noted. Presence of diabetes mellitus, hypertension or smoking was noted. Presence of any hypertonic solution and thromboprophylaxis for Deep vein thrombosis (DVT) were also noted.

Results:

Thrombus was detected in 33 of 100 (33.0%) patients. The incidence in males was 32.86% and in females was 33.33%. Males had a significantly higher incidence of small thrombus (P = 0.05), whereas females had a significantly higher incidence of large thrombus (P = 0.05). DVT thromboprophylaxis was not effective for CVC-related thrombosis. Hypertonic solution, presence of diabetes, hypertension or history of smoking did not increase the risk of thrombosis.

Conclusion:

CVC-related thrombosis is common and has the potential for serious complications. Females appear to be at a higher risk for larger thrombus formation. DVT thromboprophylaxis does not confer protection for CVC-related thrombosis. Color Doppler duplex sonography provides with an easily available, noninvasive means of detecting a thrombus. More studies are needed to establish a consensus for prophylaxis and treatment of asymptomatic CVC-related thrombosis.     

Effects of re-use on the physical characteristics of angiographic catheters

Five types of angiographic catheters used in current radiological and haemodynamic clinical practice at Sacré-Coeur Hospital in Montreal were studied for their mechanical sturdiness, and also with respect to the possibility that re-use could be associated with blood contamination by loose particles. Samples were taken both from new catheters and from catheters re-used up to 10 times. Routine cleaning and sterilization procedures showed no adverse effects on the maximum tensile strength and elongation at break of catheters. While some biological debris were occasionally present in re-used catheters, they appeared to be firmly fixed to the lumen surface, and they seemed unlikely to be carried into the blood stream during catheterization. On the other hand, new catheters exhibited a substantially higher loose particicle count than catheters which had been properly cleaned and sterilized. It is concluded that properly handled re-used angiographic catheters are just as safe for the patient as new catheters. The limit on the number of re-uses may depend on the care taken to avoid damage to the lumen surface during cleaning, on ageing on the catheter material and on economic considerations.     

Development of Anthron, an antithrombogenic coating for angiographic catheters

A new heparinized hydrophilic polymer (Anthron) which contains a large amount of heparin ionically bound to the polymer matrix has been developed. Anthron showed excellent and long-term blood compatibility both in animal and clinical tests. It has been clarified that the long-term blood compatibility of Anthron results from its negative membrane potential and continuous release of heparin from its surface into the blood at the rate of more than 0.01 unit/cm2 min. The application of Anthron for angiographic catheters was studied, and we evaluated the effects of our antithrombogenic angiographic catheter (AAC). As controls, polyurethane catheters (PUC), and polyethylene catheters (PEC), were studied in a similar manner. In addition, the mechanisms of thrombus formation and its complications are discussed.     

Effects of subfascial pressure in experimental deep pectoral myopathy of the fowl: an angiographic study

1. Angiography of the supracoracoid muscles of broiler breeder hens after neurostimulation of the breast muscles showed that complete ischaemia developed within 10 min and persisted for at least 1 h. After 24 h ischaemia remained only in the middle 1/4-1/3 of the muscle, coinciding with the main site of necrotic lesions found in experimental and spontaneous deep pectoral myopathy. 2. The development of ischaemia was prevented when the deep pectoral fascia was incised along its length before neurostimulation. 3. An increase in subfascial pressure in the supracoracoid was observed during 30 min after neurostimulation in both broiler breeder and lightweight hens. This was greater in the broiler breeder hens and more than sufficient to arrest blood flow. 4. During the first hour after neurostimulation an increase of 20% occurs in the weight of the supracoracoid muscle of both types of hen but only the broiler hens developed ischaemia. 5. It is suggested that the immediate cause of the ischaemia following neurostimulation is a rise in intramuscular pressure due to the increased muscle volume within an osteofascial compartment of limited size. The basic difference between the two types of bird in their susceptibility to this type of ischaemia and to deep pectoral myopathy probably lies in the relative development of the supracoracoid and its overlying fascia.     

Peritoneal catheters: a comparative study of column disc and Tenckhoff catheters

A functioning peritoneal access is crucial to the success of peritoneal dialysis. We report retrospective analysis of our experience using 44 Tenckhoff and 23 column disc, double-cuff, catheters in 46 patients receiving peritoneal dialysis. Postoperative care was identical in both groups. Both catheter groups were comparable with regards to age, sex, obesity and prior abdominal surgery. Catheter removal due to drainage failure was significantly greater with the column disc than the Tenckhoff catheters (22% vs 5%, p = 0.04). In addition, 39% of column disc catheters compared to 11% Tenckhoff catheters were removed as a result of therapy resistant peritonitis (p = 0.011). Furthermore, there was a greater incidence of peritonitis with the column disc than with the Tenckhoff catheters at the end of the first year (71% vs 42%, p less than 0.01). There was no difference between the two groups with respect to other complications, such as pericatheter leak, catheter infections, catheter cuff-extrusion or hernia. Our experience indicates that the column disc catheter is associated with higher complication rates and does not offer any advantage over the Tenckhoff catheter.     

Buckling test as a new approach to testing flexural rigidities of angiographic catheters

The general design of catheters is bound by many needs. Angiographic catheters must be rigid enough to be torquable and to maintain lumen structural integrity, but also flexible enough to bend with the curves of a blood vessel. They should cause minimal tissue damage; avoid biocompatibility-related complications, and be reliable over time. This study proposes a new testing approach to clearly identify the flexural rigidity of catheters by using a buckling test to evaluate the peak compressive load. This study also tests several angiographic catheters for axial and torsional rigidity. Seven different catheters used for short-term procedures, with and without reinforcement and of various sizes, were evaluated as a preliminary evaluation of test methods for future in vitro testing of catheters; it was found that the buckling test works very well and provides repeatable results.     

Lenticulostriate arteries in aging process: an angiographic study

Histological studies describe in detail the changes of the small arteries wall with controversial results concerning lumen narrowing during the aging process. In this study, the anatomic and the angiographic parameters of the medial and lateral lenticulostriate arteries were analysed in 64 carotid angiograms. Only 20% of the total number of lenticulostriate arteries were shown on angiograms. Collateral branches were rarely visible, especially those of medial group. The course of the lenticulostriate arteries was mostly straight or moderately tortuous. No significant differences were noted in any of the measured parameters when compared with the age (p greater than 0.05). It appears that age-related changes spread over external layers of small arteries, with no lumen narrowing or filling defect.     

Immunohistological analysis of experimental gingivitis in humans.

Immunohistological analysis of experimental gingivitis in humans was carried out to provide a baseline for the study of immunoregulatory mechanisms in chronic inflammatory periodontal disease. Using a panel of monoclonal antibodies in an avidin biotin immunoperoxidase technique, T cell subsets were identified and the pattern of Class II major histocompatibility complex (MHC) antigens determined. Twenty third-year dental students took part in the study. Following the cessation of oral hygiene procedures, gingival biopsies were taken from each of five students at days 0, 4, 8 and 21 during the development of the inflammatory lesion. Each student had one biopsy which healed uneventfully. The T4:T8 ratio showed only slight variation over the time course of the lesion varying from 2.18:1 at day 0 to 2.48:1 at day 4. At all stages the T cells displayed both HLA-DR and HLA-DQ antigens, but less than 10% had detectable IL-2 receptors. The predominant macrophage population was acid phosphatase + ve, adenosine triphosphatase -ve, HLA-DR+ and HLA-DQ+ antigens suggesting an activated phagocytic population. During the development of the lesion, the number of intraepithelial Langerhans cells (T6+) increased but there appeared to be a discrepancy between HLA-DR and HLA-DQ expression on these cells. Similarly, the keratinocytes expressed HLA-DR but failed to express HLA-DQ at any stage. These results suggest that the developing gingival lesion is a well controlled lesion and follows a similar pattern to a controlled delayed type hypersensitivity (DTH) response.     

Randomized study of temporary hemodialysis catheters

Temporary catheters are still essential for acute dialysis access but their performance has not been compared in randomized trials. We conducted a randomized trial of our standard catheter and a newly designed catheter. The primary outcome was maximized blood flow over the entire use of the catheter. Seventy-six patients provided maximum blood flows. The new catheter provided an average blood flow of 349 ml/min and the standard catheter provided flows of 320 ml/mm (p=0.09). Lumen reversal occurred in 56.8% of dialysis sessions with the standard catheter compared to 27.4% with the new catheter (p<0.001). Left-sided internal jugular catheters and catheters inserted in females provided 103 ml/min and 36 ml/min less blood flow, respectively, compared to right sided catheters and catheters placed in males. Approximately 20% of catheters were removed for poor blood flow. Left sided catheters and catheters in females were more likely to need removal for malfunction but catheter design did not influence removal rates.     

Spleno-gonadal fusion: anatomic and angiographic study of a case

The authors report a case of spleno-gonadal fusion in which the advantage of an angiographic study permitted, for the first time, an analysis of the vascularization of this malformation. The embryologic study explains the malformations associated with the continuous type of spleno-gonadal fusion.     

Facilitation of the withdrawal reflex by repeated transcutaneous electrical stimulation: an experimental study on central integration in humans

In the present human study, we aimed to investigate the facilitation of both the subjective pain responses, and the withdrawal reflex to consecutive transcutaneous electrical stimuli as measures of temporal summation. The frequency (0.5–20 Hz) and intensity (0.4–0.8 times the reflex threshold,  ×RT) of the electrical stimuli were systematically varied. When using repeated stimulation, the stimulus intensity that evoked pain was lower than that required by a single stimulus (temporal summation). Temporal summation leading to pain was found to depend significantly upon both frequency and intensity (e.g. stimulation at 1 Hz caused summation at 0.8 × RT, whereas stimulation at 20 Hz caused summation at 0.6 × RT). The strongest reflex facilitation, and hence the strongest pain intensity was obtained for stimulation at 10–20 Hz at an intensity of 0.8 × RT. In conclusion, the results of the present human study demonstrate clearly that a stimulus that is perceived as a localised, repetitive tactile tap can be integrated and cause severe pain. This suggests that pathologically generated sparse nociceptive afferent activity causes strong pain by central integration. This might be one mechanism to explain why clinical conditions can become excruciatingly painful despite the fact that the pathophysiological changes seem to be marginal (e.g. minor nerve trauma). Received: 26 April 1999 / Accepted: 12 August 1999     

Somatosensory off-response in humans: an ERP study

Quick detection of changes in the sensory environment is very important for survival, resulting in automatic shifts of attention to the event and the facilitation of subsequent processes to execute appropriate behaviors. The abrupt onset or offset of a sensory stimulus should also activate the neural network detecting changes. To test this hypothesis, we compared cortical on- and off-responses using somatosensory-evoked potentials (SEPs) elicited by a train of electrical pulses delivered to the right hand in eight healthy volunteers. SEPs were recorded from 15 electrodes on the scalp at three different interstimulus intervals (ISIs, 50, 20, and 10 ms) under two sets of conditions (attended and unattended). Both the onset and offset of stimulation evoked two similar components, P100 and N140, in the attended and unattended conditions. The latency of P100 and N140 in response to stimulus onset did not differ among the three ISIs, while the latency of both components in response to stimulus offset was significantly longer for the longer ISI; that is, detection of the cessation of the stimulation was based on short-term memory of the stimulus frequency. The present results supported a cortical network triggered by both the onset and offset of sensory stimulation. In this network, the change is automatically detected using a memory trace by comparing the abrupt event (on or off) with the preceding condition (silent or repetitive stimuli).     

Thrombosis prevention trial: follow-up study of practical implications.

The impact of randomised controlled trials on subsequent practice has only occasionally been assessed. Doing so is particularly necessary when unusual and possibly controversial treatments are being used. The aim of this study was to assess the practical implications of the results of the placebo-controlled primary prevention thrombosis prevention trial, in which the active treatment regimens were combined warfarin and aspirin, warfarin alone, and aspirin alone. Both active agents were given in low doses. Decisions on post-trial management were sought about men who continued with randomly-allocated treatment until the trial ended. The results of the trial appeared to have influenced decisions about future management. While aspirin was clearly the most frequent choice, a regimen involving warfarin was also used for a substantial proportion of men. Prior experience of acceptability, effectiveness, and safety probably played a significant part in decisions to continue with or switch to a warfarin-containing regimen. The findings may provide a measure of reassurance about the value of oral anticoagulation in other settings, particularly atrial fibrillation where, despite the results of trials showing major reductions in stroke, anticoagulation is underused.     

Bacteriology of experimental gingivitis in young adult humans.

From replicate trials of experimental gingivitis in four periodontally healthy subjects, 166 bacterial species and subspecies were detected among 3,034 randomly selected isolates from 96 samples. Of these bacteria, Actinomyces naeslundii (serotype III and phenotypically similar strains that were unreactive with available antisera), Actinomyces odontolyticus (serotype I and phenotypically similar strains that were unreactive with available antisera), Fusobacterium nucleatum, Lactobacillus species D-2, Streptococcus anginosus, Veillonella parvula, and Treponema species A appeared to be the most likely etiological agents of gingivitis. Statistical interpretations indicated that the greatest source of microbiological variation of the total flora observed was person-to-person differences in the floras. The next greatest source of variation was the inflammatory status of the sample sites. Person-to-person differences were smallest at experimental day 4. The floras became more diverse with time and as gingivitis developed and progressed. Analyses indicated that sequential colonization by certain species was repeatable and therefore probably predictable. Variation was relatively small between replicate trials, between two sites on the same teeth sampled on the same day, and between the same sites sampled at the same relative time in a replicate trial.     

Spinal cord and parkinsonism: neuromorphological evidences in humans and experimental studies

The involvement of the spinal cord in parkinsonism is becoming more and more evident based on human autopsies and on experimental models, obtained using specific neurotoxins or genetic manipulations. Besides Parkinson disease, other degenerative disorders characterized by parkinsonism, involve the spinal cord, and multiple neurotransmitters, apart dopamine, are altered in parkinsonism, also in their spinal projections. In the present review we discuss spinal cord pathology of different genetic or toxic experimental models of parkinsonism, as well as the neuropathological reports from autoptic cases of sporadic Parkinson disease and of other neurodegenerative conditions, overlapping with parkinsonism. Furthermore, anatomical distribution of alpha-synuclein in the spinal cord and coeruleo-spinal projections are reviewed, at the light of their possible involvement in spinal neurons degeneration. All these evidences call for an anatomical stemmed novel approach to understand specific features of parkinsonism, which might be due to such an involvement of the spinal cord. Moreover they suggest a common neurodegenerative process, underlying distinct neurodegenerative disorders, to which spinal neurons could be the more sensible.