Effect of a silver device in preventing catheter-related infections in peritoneal dialysis patients: silver ring prophylaxis at the catheter exit study

Catheter-related infections remain a significant cause of method failure in chronic peritoneal dialysis (PD) therapy. Given the increasing antibiotic resistance, such nonpharmacological strategies as local silver devices attract more interest. To establish whether a silver ring device (designed by Grosse-Siestrup in 1992) mounted onto the PD catheter and placed at the exit site at skin level is effective in preventing exit-site and other catheter-related infections, a prospective 12-month, multicenter, controlled study stratified by diabetes status was conducted. The study subjects were assessed by an extensive structured inventory, including a broad spectrum of control variables, such as age, body mass index (BMI), Staphylococcus aureus carrier status, catheter features, mode and quality of PD therapy, comorbidity, and psychosocial rehabilitation. Ten experienced German outpatient dialysis centers (seven adult, three pediatric) participated in the trial. All eligible patients (n=195) from the study area without catheter-related infections during the ascertainment period were included (incidental subjects undergoing PD therapy for at least 3 months). The main outcome measures were the occurrence of first exit-site infections (primary study end point), sinus tract/tunnel infection, and peritonitis. Ninety-seven patients were assigned to the silver ring and 98 patients to the control group. Baseline characteristics of age, sex, proportion of pediatric and incidental patients, S aureus carrier status, and other variables were similar in both groups. The incidence of infections in the silver ring group versus the control group was as follows: 23 of 97 versus 16 of 98 patients had exit-site infections, 12 of 97 versus 12 of 98 patients had sinus tract/tunnel infections, 16 of 97 versus 18 of 98 patients had peritonitis, respectively. Kaplan-Meier analysis for the probability of an infection-free interval showed no statistical difference (log-rank test) between the two groups. Displacement of the silver ring contributed to study termination in 6% of the study group patients, including two patients with catheter loss. Univariate analysis and multiple logistic regression identified younger age (<50 years), low serum albumin level (<35 g/L), number of previously placed PD catheters, short cuff-exit distance (<2 cm), and S aureus nasal carriage as risk factors for the development of exit-site infections. In conclusion, our study does not show any benefit of the silver ring in preventing catheter-related infections in PD patients. Thus, prevention of infection-related method failure in PD still has to rely on conventional antibiotic treatment strategies and less so on alternative methods.     

Acute spinal cord injury: MR imaging at 1.5 T

Thirty-seven magnetic resonance (MR) imaging studies were performed with a 1.5-T magnet and surface coils in 27 patients with suspected spinal cord injuries. Imaging was performed 1 day to 6 weeks after injury. Cord abnormalities were seen with MR in 19 patients, while skeletal and/or ligamentous injuries were seen in 21 (78%). Three types of MR signal patterns were seen in association with cord injuries. Acute intraspinal hemorrhage was seen in five patients with cord injuries and demonstrated decreased signal intensity on T2-weighted images obtained within 24 hours of injury. Cord edema and contusion had high signal intensity on T2-weighted images and were observed in 12 cases with cord injury. Neurologic recovery, determined in 16 patients, was insignificant in patients with intraspinal hemorrhage; however, patients with cord edema or contusion recovered significant neurologic function. MR at 1.5 T is extremely useful in the diagnosis of acute cord injury and also demonstrates potential in predicting neurologic recovery.     

Mitral stenosis: evaluation with MR imaging after percutaneous balloon valvuloplasty

To evaluate the pathoanatomic findings of mitral valve stenosis and changes after percutaneous balloon valvuloplasty (PBV), magnetic resonance (MR) imaging was performed in 23 patients. The patients were imaged with a 2.0-T system within 1 week before and 3-10 days after PBV. The angle of the interatrial septum was measured on the transverse image to facilitate a successful transseptal puncture. On MR images, the mean transverse and anteroposterior diameters of the left atrium at the level of the aortic root in the ventricular diastolic phase decreased significantly after PBV. Areas of flow-related intraluminal signal intensity detected in the left atrial cavity of 17 patients (74%) before the procedure disappeared in 15 patients after the procedure. Other MR imaging findings after PBV were the disappearance of intraluminal signal intensity in the pulmonary artery, normal curvature of the interatrial and interventricular septa, and pericardial effusion as a complication. MR imaging was thought to provide useful information before and after PBV in patients with mitral stenosis.     

Recurrent brief depression and its relationship to seasonal affective disorder

Summary Recurrent brief depression (RBD) and seasonal affective disorder (SAD) have been both recently described as subgroups of major depression (DSM-III-R). We have established a relationship between these two syndromes in a cohort of 42 outpatients who presented themselfes to a clinic for seasonal affective disorder at the Psychiatric Department of the University of Bonn, FRG. Our preliminary data indicate that 31% of the patients who were diagnosed as suffering from either SAD or its subsyndromal form (S-SAD) can also be categorized as RBD (RBD-seasonal) in a 1-year observation period. During the time span of 1 year RBD-seasonal patients had a mean number of 20 (SD 9) episodes compared with 6 (SD 5) episodes (P<0.001) in the group of seasonal patients without BRD. These episodes were accentuated in fall/winter and outnumbered those in spring/summer significantly (P<0.001). The mean duration of each episode was 4.6 (SD 2.6) days in the RBD-seasonal group and 21.8 (SD 29) in the non-RBD-seasonal group. Patients with RBD-seasonal experienced seasonal changes as more of a problem and reported a lower percentage of first-degree relatives with a history of depression than the non-RBD-seasonal group.     

Changes in the excitability of Renshaw cells due to orthodromic tetanic stimuli

Summary Monosynaptic extensor reflexes and orthodromically activated Renshaw cells were recorded simultaneously before, during and after intermittent tetanization of gastrocnemius nerves. Renshaw cells of both short and long latency (with respect to the reflex) were studied. During potentiation, the cells with short latency responded with an increase, those with long latency with a decrease in number of spikes per burst. After the end of tetanization, the burst length of both types remained greater than that before PPT for some time.Supported by the Deutsche Forschungsgemeinschaft (SFB 33 Nervensystem und Biologische Information).     

Glucagon in experimental intussusception

A standard type of ileocolic intussusception was produced in 69 puppies and the effect of glucagon on the hydrostatic reduction of the intussusceptions evaluated in a prospective, double-blind study. The reductions were attempted at intervals varying from 18 to 60 hr following the production of the intussusceptions. The overall reduction rate was 70% and there was no statistical difference in this rate between the animals receiving glucagon and those receiving placebos. None of the gangrenous intussusceptions were reducible with the hydrostatic pressure technique, irrespective of whether glucagon was used or not. A further evaluation was made of those animals in whom successful reductions were accomplished by the hydrostatic pressure method. Glucagon did result in significantly easier reductions, and an earlier return of normal vascular supply as measured by color and by arterial pulsations as compared to the control group.     

Muscle surface pH as a monitor of tissue perfusion and acid-base status

Muscle pH, arterial pH, and blood gases were measured in 21 anesthetized dogs. After an initial control period, the animals were subjected to one of the following: major arterial occlusion in the limb being monitored, sever hemorrhage, hypoxia, or hypothermia (28°C). Muscle pH fell rapidly with a decrease in muscle perfusion caused by arterial occlusion or by hemorrhage, without any significant change in arterial pH. In hypoxia, muscle pH varied directly with arterial pH. Hypothermia under anesthesia did not affect muscle pH.