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Biomedical subjects

R Mactier

Publications and source records attributed to R Mactier.

11 recordsLinked to original sources
PubMed1997

Long-term vascular access for hemodialysis using silicon dual-lumen catheters with guidewire replacement of catheters for technique salvage.

Difficulties in creating vascular access in patients on hemodialysis are encountered in most dialysis centers. This is usually due to a lack of suitable peripheral vessels due to previous access surgery in patients on long-term hemodialysis, but also may be seen in some patients de novo, particularly diabetics and patients with peripheral vascular disease. Surgical techniques used to overcome this problem vary depending on patient characteristics and, to a certain extent, on local expertise/preference. We report our experience of using silicon dual-lumen hemodialysis catheters over a 3-year period; during this time, 54 catheters were inserted into 32 hemodialysis patients. The indication for this procedure in 52 catheters (31 patients) was either exhausted vascular access or obvious difficulty identifying a suitable peripheral blood vessel. Of the catheters inserted, 20 were placed into subclavian veins by primary insertion (ie, patients did not have existing subclavian catheter); 34 were replaced over a guidewire (a procedure used to allow technique salvage). The catheter survival rate was 72.7% at 90 days and 48.7% at 1 year. Corresponding rates at 90 days and 1 year for technique survival were 93.3% and 81.8%, respectively. The mean catheter and technique survival was 387 (95% confidence intervals [CIs], 273, 502) and 844 (95% CIs, 684, 1,005) days, respectively. Poor flow accounted for 70.4% of catheter failures and, despite 18 episodes of catheter-related sepsis, no catheters were lost due to infection. Factors identified as leading to reduced catheter survival were left-sided placement and catheter tip placement in the superior vena cava (as opposed to right atrial placement). We did not observe poorer survival or increased sepsis in catheters replaced over a guidewire, and would advocate this technique as a means of salvage in this group of patients.

Adult↗
PubMed1996

Sclerosing peritonitis occurring in a hemodialysis patient.

The pathogenesis of sclerosing peritonitis is poorly understood. In patients with end-stage renal failure, it has been described in association with continuous ambulatory peritoneal dialysis (CAPD), although it has not been described in patients treated exclusively by hemodialysis. We present a case of sclerosing peritonitis occurring in a 47-year-old man who was treated solely by hemodialysis. Additionally, the patient was diagnosed as having "nephrogenic ascites" 5 years before developing sclerosing peritonitis, and we discuss a possible link between these two conditions.

Ascites↗
PubMed1992

Atrial natriuretic factor improves renal function and lowers systolic blood pressure in renal allograft recipients treated with cyclosporin A.

OBJECTIVE: Atrial natriuretic factor (ANF) has several properties which suggest that it may ameliorate cyclosporin A nephrotoxicity. We therefore investigated the response to a pharmacological dose of ANF in renal transplant recipients treated with cyclosporin A. DESIGN: A single-blind randomized crossover design comparing the renal and haemodynamic effects of D-glucose (placebo) with ANF. METHODS: Seven patients with stable renal function following renal transplantation were studied under maximal water diuresis. Glomerular filtration rate and effective renal plasma flow were estimated from clearances of inulin and para-aminohippurate, respectively. RESULTS: Plasma ANF levels increased significantly in association with increased diuresis and natriuresis. Glomerular filtration rate was unchanged after placebo but increased significantly after ANF fusion. Likewise, effective renal plasma flow increased significantly with ANF infusion. There was a significant fall in systolic blood pressure, with no apparent change in heart rate and diastolic blood pressure. CONCLUSIONS: These results suggest that ANF may have beneficial effects in protecting against cyclosporin A-induced nephrotoxicity and hypertension.

Atrial Natriuretic Factor↗
PubMed1992

Role of lymphatics in peritoneal dialysis.

There is a renewed interest in understanding the precise role of lymphatics in the ultrafiltration kinetics during peritoneal dialysis. In the normal state, lymphatics draining the peritoneal cavity are the principal means of removal of intraperitoneal isosmotic fluid and macromolecules. During a hypertonic peritoneal dialysis exchange, after peak intraperitoneal volume is achieved, fluid removal proceeds at an almost linear rate, causing intraperitoneal fluid volume to reduce. The isosmotic fluid removal from the peritoneal cavity could occur through the microcirculatory capillaries or through the lymphatic capillaries draining the peritoneal cavity. Animal and human studies suggest that this fluid loss occurs primarily through lymphatics. The two indirect methods of lymph flow measurements, plasma appearance and peritoneal disappearance of tracer colloid, show conflicting results. Although direct measurement of lymph flow rates through cannulation of mediastinal lymph vessels in animals suggests a significant flow through the lymph channels in response to intraperitoneal fluid instillation, lymph flow modification at the lymph node level may prevent use of this technique to assess the precise role played by lymphatics in fluid kinetics during peritoneal dialysis. By analogy with ascites and by extrapolation from previous studies of drain volumes after infusion of isotonic and hypertonic solutions, the average daily lymph absorption rate during CAPD may be predicted to be at least 1 liter per day.

Absorption↗
PubMed1992

Non-renal indications for peritoneal dialysis.

Peritoneal dialysis is rarely indicated for conditions other than end-stage renal failure. Patients with refractory congestive cardiac failure, who are awaiting cardiac transplantation or have potentially reversible cardiac disease, appear to benefit from CAPD. The prognosis of patients with fulminant hepatic failure or severe acute pancreatitis has not yet been shown to improve with the addition of peritoneal dialysis to standard supportive treatment. Isolated reports have suggested that patients with hypothermia, hyperthermia, dialysis-associated ascites and drug poisonings may be treated successfully with peritoneal dialysis. The above indications are encountered infrequently and renal failure remains the only major indication for commencing patients on peritoneal dialysis.

Ascites↗
PubMed1987

The kinetics of ultrafiltration during peritoneal dialysis: the role of lymphatics.

Net ultrafiltration was measured directly during hypertonic peritoneal dialysis exchanges in rats. Simultaneously, lymphatic absorption was measured by monitoring the disappearance of albumin in the instilled dialysis solution from the peritoneal cavity. The albumin method for measuring lymphatic absorption was also tested in rats absorbing Lactated Ringer's solution from the peritoneal cavity where absorption rate could also be measured directly. The findings suggest the following: 1.) lymphatic absorption rate is similar with both hypertonic dialysis solutions and Lactated Ringer's solution; 2.) lymphatic absorption is substantial and net ultrafiltration is well below true transcapillary ultrafiltration; and 3.) in our model, lymphatic absorption occurs at a relatively constant rate over six hours of dwell time.

Absorption↗
PubMed1983

Early-onset chronic renal failure as a complication of acute intermittent porphyria.

In a retrospective survey of patients who have had a proven attack of acute intermittent porphyria (AIP) in the West of Scotland a highly significant association (p less than 0.001) was observed between AIP and the development of early-onset chronic renal failure. Six patients with AIP and chronic renal failure arising in early middle-age are described. As no other cause could be attributed to the renal failure three possible causal links between these two conditions were considered, namely, enhanced susceptibility to analgesic nephropathy, porphyria-induced hypertension, and nephrotoxic effects of porphyrins and their precursors. We suggest that porphyria-induced hypertension is the most important factor in causing early-onset chronic renal failure in acute intermittent porphyria.

Acute Disease↗