Haemodialysis vascular access function in dialysis patients at the Kenyatta National Hospital

Background: The number of patients requiring renal replacement therapy (RRT) worldwide has been on the rise. Vascular access is the lifeline for these patients when haemodialysis (HD) is the treatment of choice. Access-related morbidity is a leading cause of hospitalization so that the function and patency of access are essential for the optimal management of patients. There is a need to recognize when a vascular access is dysfunctional because intervention must maintain function as well as preserve future vascular access sites.Methods: This was a cross-sectional study that evaluated the haemodialysis vascular access function in patients undergoing chronic haemodialysis at the Kenyatta National Hospital, Nairobi, Kenya. Peak access blood flow rates, urea reduction ratio (URR) and Kt/V were analysed in 150 patients.Results: The temporary (non-tunnelled) central venous dialysis catheters had poor function, with only 48% achieving a mean blood flow rate > 300 mL/min. The comparable rate for arteriovenous fistulae (AVF) was 88% and for tunnelled dialysis catheters 82%. One-quarter of the patients had a URR < 65%. Higher mean blood flow rates were associated with higher URR (P = 0.004) and Kt/V (P = 0.009) values. AVF stenosis was present in 12.5% and thrombosis in 3% of patients. Aneurysms were the commonest AVF complication (47%) but were not haemodynamically significant.Conclusions: Tunnelled haemodialysis catheters offered adequate blood flows and achieved adequate delivered dialysis, comparable to arteriovenous fistulae. Non-tunnelled catheters delivered poor blood flow rates and dialysis dose. Greater blood flow rates were associated with a higher delivered dialysis dose. There is a need for routine surveillance and affordable interventional procedures to prevent loss of vascular access

Comparison of a new opposed phase imaging protocol to the standard conventional MRI protocol in demonstration of lumbar degenerative disc disease at 1.5T.

Purpose: The purpose of the study was to compare diagnostic yield of a new Opposed Phase Imaging protocol [OPI] to the standard conventional MRI protocol [CONV] in demonstration of lumbar degenerative disc disease at 1.5T. Materials and Methods: A total of 102 patients suspected of lumbar disc disease were examined using the two protocols. Images from both protocols were then analyzed independently by two radiologists. Category of disc disease[normal, bulge ,protrusion, extrusion] and anatomic clarity of spinal structures related to disc disease[nerve roots, osteophytes, modic changes and hemangiomas ] were assessed using a standard 4 point scoring scale [1=inadequate,2 =adequate,3=normal ,4=optimal.] Comparison of the results from the two protocols was done using wilcoxons analysis, Mann Whitney test and the student paired t test. Results: Of the 510 discs (in 102 patients) examined by OPI and conventional protocols, 488[96%,CI 93.93-97.45] had concordant diagnosis for disc disease and associated pathologies. Only 1% of the discordant disc lesions showed radiologically significant findings. There was no statistically significant difference [P \u3e0.05] among the two radiologists in the subjective scores given for the two protocols. OPI received similar scores to conventional protocol in optimally demonstrating osteophytes, modic changes and hemangiomas [p \u3e 0.001].OPI however received significantly lesser scores [P\u3c 0.001] for anatomic clarity of the discs and nerve roots. The average imaging time for OPI protocol was 7 minutes which was significantly shorter [p \u3c0.001, CI 7.07-7.19] than that of conventional protocol of 16 minutes. Conclusion: OPI has comparable pick up rate for pathology in lumbar degenerative disc disease despite the fact that the new protocol gives less anatomic clarity compared to the conventional protocol for discs and nerve roots. The new protocol is adequate in demonstrating other spinal structures [modic changes, osteophytes and hemangiomas] related to degenerative disc disease. OPI takes a significantly shorter imaging time and can therefore be an alternative time saver in imaging lumbar disc disease