Individually adjusted absolute blood volume feedback control: A promising solution for intradialytic hypotension.

INTRODUCTION: Intradialytic hypotension (IDH) remains one of the most frequent complications associated to hemodialysis (HD), frequently triggered by a reduction in absolute blood volume (ABV) not compensated by vascular refilling. A recently developed dilutional method allows routinary measurement of ABV and, by a simple algorithm, may turn blood volume monitor (BVM) guided UF (ultrafiltration) biofeedback into an ABV control, automatically adjusting UF rate to maintain ABV above a preset threshold. The aim of this study is to identify an individual critical ABV threshold and test the ability of an ABV feedback control to avoid IDH. METHODS: We studied 24 patients throughout three consecutive midweek HD treatments. ABV and blood pressure (BP) were measured every 30 min and anytime the patient referred any symptoms to identify each patient's critical ABV (ABV at the time of hypotension). A fixed bolus dilution approach at the start of HD was used to calculate ABV. Then, patients were followed through three additional HD treatments and IDH development was analyzed. FINDINGS: Seventy-one treatments performed in 24 patients. ABV monitoring showed a constant decrease as HD treatment progressed. Thirteen IDH events were observed in eight different patients, with a mean systolic BP drop in IDH treatments of 37.38 ± 4.31 mmHg and a mean adjusted ABV at hypotension of 71.07 ± 14.88 mL/kg. Critical ABV was individually set in patients prone to IDH. As expected, ABV feedback control successfully maintained ABV over preset critical ABV. IDH events were avoided in 21 out of 22 treatments performed. ABV drop was successfully reduced, as well as SBP drop (despite similar UF than prior to ABV feedback control implementation). DISCUSSION: ABV feedback control avoided IDH in 21 out of 22 treatments performed by maintaining blood volume above critical ABV, significantly reducing ABV variations without compromising prescribed UF.

Impact of dialysate sodium concentration on vascular refilling.

BACKGROUND: Although relationship between dialysate sodium concentration and hemodynamic stability has been well studied over the years, outcomes of absolute blood volume (ABV) maintenance and vascular refilling volume (Vref ) modifications were not included, as its analysis has not been easily accessible to direct investigation. However, recent studies report a simple and feasible methodology to assess ABV and Vref during hemodialysis (HD) treatments. It is the aim of this study to analyze whether sodium concentration in dialysate modifies ABV drop and Vref . METHODS: The study was performed in 19 patients under HD. During three different sessions, sodium concentration in dialysate was randomized to three different profiles: low sodium concentration (LNa, 138 mEq/L), neutral sodium concentration (NNa, 140 mEq/L), and high sodium concentration (HNa, 143 mEq/L). ABV and Vref were calculated using Kron et al methodology. RESULTS: Predialysis values of the measured parameters showed similar results for the three profiles. Sodium concentration showed an effect on ABV drop, Vref, and vascular refilling fraction (Fref ). Pair-wise comparison revealed mean ABV decreased 0.21 L less when using HNa profile versus LNa profile (p = 0.027), a mean Vref increase of 0.39 L (p = 0.038), and a mean Fref increase of 9.94% (p = 0.048). CONCLUSIONS: This study shows that the use of HNa profiles increases Vref and Fref and reduces ABV drop during dialysis treatments when compared to LNa profiles.

Safety of renal biopsy bleeding prophylaxis with desmopressin.

BACKGROUND: Percutaneous renal biopsy (PRB) is invasive, and bleeding-related complications are a concern. Desmopressin (DDAVP) is a selective type 2 vasopressin receptor-agonist also used for haemostasis. AIM: To evaluate the side effects of intravenous (IV) weight-adjusted desmopressin preceding PRB. METHODS: This was a retrospective study of renal biopsies performed by nephrologists from 2013 to 2017 in patients who received single-dose DDAVP pre-PRB. RESULTS: Of 482 PRBs, 65 (13.5%) received DDAVP (0.3 µg/kg); 55.4% of the PRBs were native kidneys. Desmopressin indications were altered platelet function analyser (PFA)-100 results (75.3% of the patients), urea >24.9 mmol/L (15.5%), antiplatelet drugs (6.1%) and thrombocytopaenia (3%). Of the 65 patients, 30.7% had minor asymptomatic complications, and 3 patients had major complications. Pre-PRB haemoglobin (Hb) <100 g/L was a risk factor for Hb decrease >10 g/L, and altered collagen-epinephrine (Col-Epi) time was a significant risk factor for overall complications. Mean sodium decrease was 0.6 ± 3 mmol/L. Hyponatraemia without neurological symptoms was diagnosed in two patients; no cardiovascular events occurred. CONCLUSION: Hyponatraemia after single-dose DDAVP is rare. A single IV dose of desmopressin adjusted to the patient's weight is safe as pre-PRB bleeding prophylaxis.

Comparison of in situ preservation techniques for kidneys from donors after circulatory death: a systematic review and meta-analysis.

BACKGROUND: Several techniques have been developed to reduce the warm ischaemic injury of donation after circulatory death (DCD) organs before procurement. There are scarce data about the in situ preservation techniques for kidney graft outcomes. The aim of this systematic review was to evaluate the best in situ preservation method for kidney graft outcomes from organs obtained from controlled and uncontrolled DCD. METHODS: A systematic review of the PubMed (MEDLINE), Embase, LILACS and Cochrane databases was conducted. Studies that compare two or more in situ preservation techniques were identified and included. Only studies which provided enough data to calculate odds ratio were eligible for meta-analysis. PROSPERO registration: CRD42020179598. RESULTS: The search strategy yielded 7,121 studies. Ultimately, 14 retrospective studies were included. Because of heterogeneity, the included studies provided weak evidence that normothermic regional perfusion (NRP) is the best in situ preservation technique in terms of delayed graft function (DGF) rates. Regarding primary nonfunction (PNF), we carried out a meta-analysis of 10 studies with a pooled OR of 0.83 (95% CI: 0.40-1.71), for the NRP. In regard to DGF, pooled OR for NRP was 0.36 (95% CI: 0.25-0.54). CONCLUSIONS: NRP in the DCD donor could improve kidney graft function and be considered the in situ preservation technique of choice for abdominal organs.

Absolute blood volume variations and vascular refilling in hemodialysis patients.

The imbalance between ultrafiltration volume (UF) and vascular refilling is considered a major cause for intradialytic hypotension. Recent studies report a noninvasive method to estimate vascular refilling (VREF ) by determining absolute blood volume (ABV). It was the aim of the study to analyze variations in ABV in a group of hemodialysis (HD) patients and examine VREF . Thirty one stable chronic HD patients were studied, aged 71.07 ± 13.31 years. Dialysis duration and UF requirements were based on physician prescription. VREF was calculated as: VREF  = VUF  - ΔV where ΔV is ABV variation during dialysis treatment. ABV at the beginning of the dialysis was 6.00 ± 2.39 L (92.82 ± 33.17 ml/kg) and at the end 5.38 ± 2.32 L (82.07 ± 31.41 ml/kg). Prescribed UF was 2.64 ± 0.83 L. Mean VREF was 2.05 ± 0.80 L, with a refilling fraction of 75.75 ± 12.79%. VREF was strongly correlated with UF volume (r2 0.877), and with pre-dialysis volume overload (r2 0.617). Patients under beta-blocker treatment showed significantly lower FREF . ABV measurement is an easy and noninvasive method that allows us to study VREF during HD. We found a strong correlation between VREF and UF.

Absolute blood volume variations during hemodialysis: Does dialysate temperature play a role?

BACKGROUND: Vascular refilling occurs to preserve hemodynamic stability during hemodialysis (HD). Recent studies report a feasible and noninvasive method to determine absolute blood volume (ABV), and estimate vascular refilling during HD. The objective of this study is to analyze if lowering dialysate temperature modifies variations in ABV during HD. METHODS: The study was performed in 50 patients under HD. During two different sessions, relative blood volume was assessed using dialysate temperatures of 35.5°C (cool dialysate) and 36.5°C (neutral dialysate). ABV and vascular refilling were calculated using Kron et al methodology. RESULTS: Thirty-nine intradialytic morbid events (IMEs) were observed in 30 patients, 14 under cool dialysate and 25 during neutral dialysate. We did not found statistically differences in ABV or in refilling volume between cool and neutral temperature. When analyzing apart only those patients who presented IME, we observed lower drop in ABV in the 35.5°C dialysate treatments (0.57 L) versus 36.5°C dialysate treatments (0.71 L). When cool dialysate was used, the vascular refilling fraction tended to be higher, but data did not turn statistically significant. CONCLUSIONS: In selected groups of patients the use of cool dialysate induces lower ABV variations that could improve hemodynamic stability during HD treatments.

Relapsing peritonitis and taurolidine peritoneal catheter lock: One center experience.

BACKGROUND: Relapsing peritonitis due to the development of a biofilm in the catheter's lumen remains an important complication of peritoneal dialysis therapy that endangers technique continuity. Taurolidine catheter lock has proven efficient reducing infection rates in permanent hemodialysis catheters based on its biocidal activity and biofilm detachment effect. Efficacy evidence on its use in peritoneal dialysis catheters is lacking. METHODS: We retrospectively analyzed all relapsing peritonitis episodes from June 2018 until October 2019 in our center. Patients were identified and data were collected from our electronic renal registry and patient's records. RESULTS: Six patients were identified during the study period. Most patients (66.6%) were on automated peritoneal dialysis and the median duration of peritoneal dialysis before the episode of taurolidine was started was 43.66 ± 29.64 months. Mean taurolidine doses were 10 (range: 9-11) and 83.3% (five patients, with peritonitis caused by Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Corynebacterium propinquum) had a favorable response and microbial eradication without relapses after taurolidine treatment. Only one patient relapsed by the same organism (Corynebacterium amycolatum) due to non-adherence to the antibiotic treatment prescribed. None of the patients experienced any relevant adverse events, with only two out of six presenting mild transient abdominal discomfort. CONCLUSION: We believe that peritoneal catheter taurolidine lock could be considered in cases of relapsing or refractory peritonitis, as it could prevent catheter removal and permanent switch to hemodialysis in selected cases, although literature is scarce and further studies are needed.

Taurolidine Peritoneal Dialysis Catheter Lock to Treat Relapsing Peritoneal Dialysis Peritonitis.

Peritonitis remains a primary challenge for the long-term success of peritoneal dialysis (PD) technique and one of the main reasons for catheter removal. Prevention and treatment of catheter-related infections are major concerns to avoid peritonitis. The use of taurolidine catheter-locking solution to avoid the development of a biofilm in the catheter's lumen has obtained good results in hemodialysis catheters for reducing infection rates, although there is scarce literature available regarding its utility in PD. We describe the case of a woman in her 60s who developed relapsing peritonitis due to Pseudomonas aeruginosa, with no possibility of removing peritoneal dialysis catheter because she was not a suitable candidate for hemodialysis. After the fourth peritonitis episode caused by Pseudomonas species, the use of taurolidine catheter-locking solution was initiated. She received a total of 9 doses, with a favorable microbiological and clinical outcome and no further relapses more than 10 months after taurolidine PD catheter lock treatment was started. We report the successful elimination of an aggressive bacteria after taurolidine PD catheter lock use, with no relevant adverse events.