The effect of needle gauge on recirculation, venous pressure and bleeding from puncture sites.

We performed a prospective, randomized study of various needle gauges and the effect on recirculation, venous pressure, and puncture site bleeding. All patients (n = 21) in our unit consented and participated. We studied 14, 15, 16, and 17 gauge needles, 2.5 cm in length with a "backeye" conformation. Each of the four needle gauges were studied twice in a randomized order. Needle were placed with the arterial needle pointed toward the arterial anastomosis and the venous needle pointed toward the venous anastomosis. The arterial and venous needles were placed at least 6 cm apart. Venous pressure and bleeding from puncture sites were recorded and analyzed in relation to needle gauge. Recirculation was calculated using the 3 needle technique. Blood pump flow rates (QBS) of 200 and 500 cc/min were studied with each needle gauge during the first 0.5 hour of dialysis. Data were analyzed using MANOVA and chi square. Recirculation at a QB of 200 cc/min was similar for all needle gauges (13-15%). At a QB of 500 cc/min the recirculation was 19% for the 17 gauge needles and 27% for the 14 gauge needles (p < 0.01). Venous pressure increased with decreasing needle size: 83 mmHg at QB 200 cc/min for 14 gauge needles, 147 mmHg at QB 200 cc/min for 17 gauge needles, and 204 mmHg and 382 mmHg respectively for QB 500 cc/min with needle gauges of 14 and 17. Bleeding occurred with 15 gauge needles on two occasions and four times with 14 gauge needles. There were no bleeding episodes with 16 or 17 gauge needles (p < 0.03). In conclusion, recirculation is greater with larger gauge needles at QB 500 cc/min. Bleeding is related to larger gauge needles. Hence, smaller gauge needles (17 gauge) appear move advantageous than larger gauge needles.

Exit-site care--is it time for a change?

Peritoneal catheter exit-site infections (ESI's) continue to impact significantly on morbidity and catheter longevity. The controversy concerning protocols for daily exit-site care continues for frequency, methodology, cleansing agent, and dressing. Routine daily exit-site care prior to January 1991 consisted of daily showers using liquid soap, povidone scrub, rinsing the shower, and drying with a 4 x 4-in. gauze pad. Catheters have always been immobilized, either with tape or an immobilizing device. Hydrogen peroxide was used only when needed to soften crust formation prior to showering. A light dressing, usually 2 x 2 in., was optional. A recent survey revealed that povidone iodine was the antiseptic of choice for catheter care in 75% of the respondents. However, povidone iodine irritates and dries the skin predisposing it to infection. ESI's are prospectively monitored as part of our quality improvement (QI) program. An incidence of 0.76 episodes/patient-year was noted between January 1989 and May 1991. Given the relative high frequency of ESI's, the protocol was modified and introduced during the January-May 1991 time frame. Routine care now consists of daily showers using only CC-500, a gentle antibacterial cleaner (Care-Tech Laboratories, Inc.), rinsing in the shower, and drying with a 4 x 4-in. gauze. Use of hydrogen peroxide and dressings has remained the same. Additionally, a protocol addressing the prophylaxis for traumatized exist sites was initiated. The incidence of ESI's has dropped significantly to 0.12 episodes/patient-year. Although our population size is small (n = 18), this study does point out the utility of prospectively monitoring trends for appropriate indicators within a QI program.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of intraperitoneal neostigmine on peritoneal transport characteristics in CAPD.

Lymphatics have been suggested to play a major role in the absorption of dialysate, which consequently affects the adequacy of peritoneal dialysis. Neostigmine has been found to decrease lymphatic absorption in rats, presumably by causing constriction of the lymphatic stomata. We investigated the effect of neostigmine on seven continuous ambulatory peritoneal dialysis (CAPD) patients in a prospective study. We performed modified peritoneal equilibration tests both with and without intraperitoneal neostigmine in a random order. Radiolabeled albumin (0.8 mg) was added to 2 liters of dialysate +/- 2.0 mg neostigmine. We evaluated ultrafiltration and creatinine, phosphate, and urea clearances. The dialysate bag and the peritoneum were scanned at the initiation and conclusion of the four-hour dwell period. We found no change in ultrafiltration, residual volumes, creatinine, phosphate and urea clearances, or albumin recovered. Of the seven patients exposed to neostigmine, four had diarrhea, abdominal cramps, nausea, and vomiting. In conclusion, we found that 2 mg i.p. neostigmine did cause significant side-effects and did not alter transport characteristics in CAPD patients.