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.

The quality of life in end stage renal disease care

The improved prognosis and survival statistics of both renal transplantation and dialysis have focused attention on the quality of life offered by these treatments. Using a standardized questionnaire, we assessed the quality of life of 612 patients undergoing renal replacement therapy at our center. Of these patients, 359 had been transplanted and 253 patients were on dialysis. Concerning the sociodemographic data, only the time on specific treatment was longer in dialysis patients than in transplanted patients (49.2 versus 55.6 months, P < 0.05). Most complaints were more common in dialysis patients than in transplanted patients. Only the side effects of medication were seen more in transplanted patients (P < 0.005). Life satisfaction was higher in transplanted patients than in dialysis patients. Dialysis patients were more anxious (P < 0.05) and more depressed (P < 0.001) than transplanted patients. Transplanted patients also felt that they had more social support than did dialysis patients. Overall life quality was almost equal between patients on hemodialysis and patients on peritoneal dialysis, and between patients on the waiting list for transplantation and those not on the waiting list. Despite a significantly better quality of life after renal transplantation, the percentage of patients working remained unchanged. (57.5% versus 57.8%, P = n.s.). We conclude that despite an improved quality of life after renal transplantation, these patients are economically not more productive than patients on dialysis.

The use of ultrasound for the placement of dialysis catheters

BACKGROUND

The jugular vein should be preferred to the subclavian vein for the placement of dialysis catheters, since subclavian catheters result in a high incidence (up to 50%) of subclavian vein thromboses and stenoses.

METHOD

We conducted a prospective, randomized study between July 1996 and March 1997 to find out whether through the use of ultrasound, the rate of unsuccessful attempts in puncturing the internal jugular vein could be reduced. Seventy-three internal jugular vein cannulations were performed on 65 patients, using the guide-wire technique (according to Seldinger). Two groups were formed randomly by lot: in the first group the position of the internal jugular vein was marked on the skin by the use of ultrasound (Picker CS9100, Convex 3.5 MHz) before disinfection and local anaesthesia took place. The puncture was performed according to this mark. In the second group, the internal jugular vein was cannulated with real-time ultrasound guidance on the monitor. Any withdrawal of the needle with a consecutive forward movement was judged as an unsuccessful attempt, whether or not a second skin puncture was performed.

RESULT

Thirty-seven punctures of the internal jugular vein with a skin mark determined by ultrasound yielded 87 unsuccessful attempts. Thirty-six punctures with real-time ultrasound guidance resulted in 10 unsuccessful attempts (P<0.01). The time from the beginning of the local anaesthesia to successful puncture was 4.8+/-2.2 min in the first group compared to 3.4+/-0.9 min in the second group (P<0.01). The cross-section of the internal jugular vein in the first group was 1.7+/-0.8 cm2 versus 1.5+/-0.8 cm2 in the second group (not significant). Neither of the two methods caused any complications.

CONCLUSION

The puncture of the internal jugular vein with real-time ultrasound guidance resulted in significantly fewer unsuccessful attempts of venepuncture without requiring additional time.

Diagnosis of iron deficiency anemia in renal failure patients during the post-erythropoietin era

The purpose of this study was to evaluate the sensitivity and specificity of laboratory methods in the diagnosis of posterythropoietin-era, iron-deficient, chronic renal failure patients. The patient population comprised 25 anemic (hemoglobin < 11 g/dL) patients with creatinine greater than 3 mg/dL; 20 were dialysis patients, two were transplant patients, and three patients had renal failure from other causes. Criteria for study inclusion were as follows: bone marrow iron was the reference standard and was graded 0 to +4, ranging from absent to diffuse homogeneous iron staining; serum ferritin concentration and serum transferrin saturation were tested in terms of sensitivity and specificity. The reference standard indicated that iron deficiency existed in 40% of patients. Neither serum ferritin nor transferrin saturation were completely adequate diagnostic tools. Serum ferritin levels less than 200 ng/dL were 100% specific for the diagnosis but only 41% sensitive. Transferrin saturation of less than 20% was 88% sensitive, but only 63% specific. By excluding patients with hypoproteinemia (transferrin values of < 150 mg/dL), the sensitivity of the test increased to 100% and the specificity to 80%. We conclude that transferrin saturation is an adequate screening tool in anemic chronic renal failure patients, provided that hypoproteinemia is not present. By determining both the serum ferritin concentration and the transferrin saturation, a high sensitivity and specificity can be achieved, even in patients with hypoproteinemia. Furthermore, we believe that on this basis, iron therapy in patients with renal insufficiency can be improved.

Treatment of dopamine-dependent shock with triiodothyronine

At the present time dopamine is the most frequently used treatment in patients with septic shock. The effects of dopamine are mediated by alpha-, beta- and dopaminergic receptors. It has been suggested that these receptors are controlled by triiodothyronine (T3). In acute septic shock circulating T3-concentrations are decreased. We have, therefore, treated in a preliminary study 11 such patients with T2-replacement by continuous infusion of T3 (100-200 micrograms/24h). Dopamine dependence was terminated. In all patients there was an increase of arterial blood pressure (BP) within 24 hrs (systolic BP rose by 34 +/- 4.2 mmHg, diastolic BP by 14.0 +/- 8.2 mmHg, resulting in an increase of the mean BP by 25 +/- 6.1 (SEM mmHg). The pulse rate was not influenced suggesting an effect on minute volume. A hypothesis is offered which explains the T3-effects as a result of its decarboxylation to a dopaminergic iodothyronine which is disturbed during the "low T3-syndrome".

[Treatment of dopamine-dependent shock with triiodothyronine: prelimary results (author's transl)]

Triiodothyronine (T3) was administered to 11 patients in septic shock. In all there occurred an increase in arterial blood pressure within 24 hours, the rise in systolic pressure being 34 +/- 4.2 mm Hg, of diastolic 14 +/- 8.2 mm Hg, corresponding to a rise in mean arterial pressure of 25 +/- 6.1 mm Hg. Haemodynamic studies in four patients suggest that the action of T3 is mediated via beta-sympathomimetic channels.

Conversion of T3 and rT3 to 3,3'-T2: pH dependency

In the extrathyroidal deiodination of T4 the importance of T3 and rT3 for the peripheral action of thyroid hormones is well documented. With the development of a specific radioimmunoassay for 3,3'-T2, a deiodination product of both T3 and rT3, we were able to characterize these subsequent enzymatic reactions as well as the degradation of 3,3'-T2 in rat liver homogenate. It was found that the reaction T3 leads to 3,3'-T2 is slow compared to the conversion of T4 to T3. The pH activity profile shows a peak at 8.4. The reaction rT3 leads to 3,3'-T2 is very fast, with an apparent KM of 4 x 10(-7) M. The reaction velocity is significantly higher in acid than in alkaline pH. The deiodination of 3,3'-T2 is also faster in the acid than in the alkaline range. It is concluded that the outer ring of T4 is more readily deiodinated in acid and the inner ring in alkaline media, and that 3,3'-T2 is mainly degraded to 3-T1. In the acid pH range T3 may accumulate and in the alkaline range rT3 by the pH characteristics of these ractions. Therefore small shifts in pH can enhance the potent inhibitory action of rT3 on the 5'-deiodination of T4 adding another mechanism to the peripheral regulation of thyroid hormone activity.

Regulation of thyroid hormone metabolism in rat liver fractions

The nature of the conversion of thyroxine (T4) to triiodothyronine (T3) and reverse triiodothyronine (rT3) was investigated in rat liver homogenate and microsomes. A 6-fold rise of T3 and 2.5-fold rise of rT3 levels determined by specific radioimmunoassays was observed over 6 h after the addition of T4. An enzymic process is suggested that converts T4 to T3 and rT3. For T3 the optimal pH is 6 and for rT3, 9.5. The converting activity for both T3 and rT3 is temperature dependent and can be suppressed by heat, H2O2, merthiolate and by 5-propyl-2-thiouracil. rT3 and to a lesser degree iodide, were able to inhibit the production of T3 in a dose related fashion. Therefore the pH dependency, rT3 and iodide may regulate the availability of T3 or rT3 depending on the metabolic requirements of thyroid hormones.

Conversion of T4 to T3 and rT3 and their cytoplasmic binding: pH dependency

The fate of T4 in target organs is conversion to T3 which is mainly responsible for the nuclear action of thyroid hormones. To further investigate this converting step the increase of T3 and its analogue rT3 in rat liver microsomes was measured by specific radioimmunoassays after adding T4 to the incubation medium. Maximal increase of T3 occurred at pH 6.0 and of rT3 at pH 9.5 indicating that two different enzymic systems may be involved in the deiodination of the tyrosyl or the phenolic ring of T4. An increase in the binding capacity of cytosol proteins for T4, T3 and rT3 with rising pH demonstrates that there is also a pH dependency of the cytoplasmic binding of these iodothyronines. These reaction conditions should not only be considered in in vitro experiments, but may also be of importance in modifying the availability of T3 for its nuclear receptors.

Studies on the postponed growth hormone secretion following the infusion of somatostatin

It is well known and also confirmed in this study that somatostatin (growth hormone inhibiting factor, GHIF) prevents the noctural GH secretion, as long as the peptide is infused. Following the infusion a rapid rise in GH levels is seen in sleeping subjects with peak values of 26.8 +/- 9.7 ng/ml compared to 31.7 +/- 4.7 ng/ml (+/- SEM) in control nights. Delayed GH peaks were seen even in the absence of slow wave sleep. No postponed GH rise was observed when subjects fell asleep again. These data demonstrate that the postponed nocturnal GH peak does not represent a rebound phenomenon to a previous trigger mechanism but is acutely sleep induced.

The effect of somatostatin on TSH levels in patients with primary hypothyroidism

Somatostatin, a growth hormone inhibiting factor (GHIF), was infused into 8 patients with primary hypothyroidism at a dosage of 1000 mug for 105 min. GHIF caused a suppression of TSH levels from 42.6 to 76.9% of preinfusion levels with a mean nadir of 65.0 +/- 4.0%;(mean +/- SEM).

L-dopa induced growth hormone secretion. Comparison with insulin tolerance test, arginine infusion and sleep induced GH-secretion

Plasma growth hormone (GH) levels following oral stimulation with 500 mg of L-dopa were determined and compared with those following arginine infusion, insulin tolerance test (ITT) and sleep induced secretion. Peak values following L-dopa were 13.3 ± 2.5 ng/ml and not different from those following arginine (16.4 ± 3. 3ng/ml) and those during nocturnal sleep (14.7 ± 1.2 ng/ml), but significantly less than GH peaks during ITT (24.9 ± 3.4 ng/ml). The rate of false negative results to L-dopa was 15% and seems to be higher than following other stimuli. – In contrast to the stimulatory effect in healthy subjects L-dopa had a suppressive effect on the GH levels in 4 patients with acromegaly.