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A Needleless Injection System (Medisystems) Maintains Erythropoeitin Plasma Levels During Dialysis

A Simpler Method for Measuring Intra-Access Pressure in Vascular Accesses

Access Surveillance Using Static Pressures

Guarded Fistula Needle (MasterGuard®) Proven To Reduce Needlestick Injuries In Hemodialysis

Not All Manufactured Blood Tubing Sets are Equal: Effects on QB and Kt/V

A Needleless Injection System (Medisystems) Maintains Erythropoeitin Plasma Levels During Dialysis
Jani A and Petersen J; ASAIO Journal, Vol 47, No 2: pp 158, 2001.

Recent Occupational Safety and Health Standards guidelines require the implementation of needleless systems in dialysis units in the state of California. It is not known whether needleless syringes deliver medication as well as traditional low dead-space needle/syringes. The purpose of this study therefore was to compare the delivery of recombinant human erythropoetin (rHuEpo) by a needleless system (MedicR Anti-Stick Needle/Connector - Medisystems, Seattle, WA, USA) with delivery using a traditional needle/syringe.

Eight patients were studied (mean age 63 years, mean duration of dialysis 22.3 months). All patients were dialysed using Fresenius F80 dialyzers (Fresenius USA, Concord CA). During the first two weeks of the study the patients received rHuEpo via the venous drip chamber injection site of a Medisystems D3-9692M9797 bloodline, either with traditional or needleless systems. Blood samples were taken immediately before 0, 10, 40, 60 min and after injection of rHuEpo and at the end of dialysis. This protocol was repeated during weeks 3 and 4 except that delivery was changed to a traditional post-venous chamber site. The serum concentration achieved with the same dose of rHuEpo, delivered by either system were compared for each patient. The rHuEpo concentration was measured using a commercially available RIA kit (Diagnostic Systems Laboratories, Texas, USA).

There were no significant differences in serum rHuEpo concentrations at any time point achieved using either delivery system. Furthermore, there was no significant advantage conferred by changing the injection site from the venous drip chamber to post-venous drip chamber. These results indicate that the Medic Anti-Stick Needle/Connector is able to reliably deliver rHuEpo, resulting in serum concentrations no different from that achieved with traditional needle/syringes.

Full paper published in ASAIO Journal, Vol. 47 No. 6 Nov/Dec 2001. Request an official reprint from Medisystems.

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A Simpler Method for Measuring Intra-Access Pressure in Vascular Accesses
Besarab A, Lubkowski T, and Frinak S; J AM Soc Nephrol, Vol 10: pp 202A (abstract A1024), 1999.

An on-going vascular access monitoring program (access pressure or access flow over time) is mandated by HCFA's translation of several NKF-DOQI guidelines into Clinical Performance Measures. We have shown that intra-access pressure can be measured from the drip-chamber transducer at zero blood pump flow by correcting for the difference in height (offset) between the drip chamber and the dialysis needle (JASN1998; 9:284). Measurements from both the arterial (AS) and venous segments (VS) increase the detection of hemodynamically significant access lesions (ASAIO J 1997; 43:M539). The multiple steps that assure accuracy also make the procedure "user unfriendly" and have limited wider acceptance of the above technique. A simple device consisting of a sterile fistula needle equipped with a pre-attached sterile hydrophobic luer connector when connected to an aneroid manometer permits direct measurement of access pressures at the time of access cannulation (Access Alert™, Medisystems). In 19 patients with PTFE grafts, we compared this technique (AA) with our standard method using the Fresenius H Dialysis Delivery System and correcting for the offset and zero-calibration error. Absolute pressures (mm Hg) and pressure ratios (absolute/mean BP) are tabulated below; all results mean ± SEM.

There were no statistically significant differences between the two methods in absolute pressure or normalized pressure ratios. The correlation between the two methods in determining the AS and VS pressure ratios was high (R2 = 0.84 for AS, R2 = 0.68 for VS) over a wide range of values with a difference of more than 0.10 units in less than 20% of measurements. All 5 grafts with stenosis were detected by the AA technique. We conclude that the Access Alert technique is a user friendly and accurate monitoring method for detecting access grafts stenosis.

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ACCESS SURVEILLANCE USING STATIC PRESSURES
Dinwiddie L, Gordon B and Holden H; Nephrol Nurs J, Vol 28, No 2: pp 129, 2001.

Surveillance of vascular access is mandated by HCFA to monitor clinical performance. Intra-access static venous pressures have been used to predict venous stenoses for many years and have been shown to be more predictive than dynamic venous pressures. This method, now greatly simplified with the use of a hydrophobic filter attached to each dialysis needle, can detect stenoses proximal to the arterial needle, between the needles, as well as distal to the venous needle. These measurements, made immediately after cannulation, take less than one minute. A normalized ratio is calculated by dividing each pressure by the systemic MAP indicating abnormality by exceeding upper limits or a change in pressures over time. Ideally each new access should be monitored for baseline pressures upon first use and followed at frequent intervals thereafter.

Using this method of surveillance we have followed 12 patients with PTFE grafts over a 4 month period and have compared findings to monthly URRs and physical examination of access. Seven patients maintained normal pressures, acceptable URRs, and negative physical exam during the initial study period. Four patients had abnormal pressures indicating venous stenoses that were confirmed with angiography along with decreased URRs and abnormal physical findings. One patient with a pre-existing SVC stenosis that is stented shows increased pressures that are correlated with the need for PTA of the stent lumen and therefore requires frequent monitoring. Increased pressures in this patient are also accompanied by ipsilateral arm swelling buy normal URRs.

We conclude that intra-access pressure monitoring can independently predict access pathology and satisfactorily monitor normal function. Ease of pressure measurements and ration calculations make it easy for any staff member who is cannulation to collect the necessary data and document it.

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GUARDED FISTULA NEEDLE (MASTERGUARD®) PROVEN TO REDUCE NEEDLESTICK INJURIES IN HEMODIALYSIS
Adams T, McCleary J, Peterson P and Cheffer B. Nephrol Nurs J, Vol 28, No 2: pp 128, 2001.

The Federal Needlestick Safety and Protection Act, signed into law on November 6, 2000, mandates that the 1991 OSHA Bloodborne Pathogens Standard (29 CFR 1930.1030) be revised to require the use of safety engineered sharps devices. There are no documented studies demonstrating the effectiveness of guarded fistula needles in reducing the incidence of needlestick injuries in hemodialysis. The purpose of this study therefore was to compare the incidence of needlesticks with a non-guarded fistula needle to a fistula needle with Engineered Sharps Injury Prevention (ESIP).

Control data regarding needlesticks with the non-guarded fistula needle was collected retrospectively at an institution with approximately 400 patients. The fistula needle with ESIP was implemented at the same institution for a subsequent period. The needlestick data for the evaluation period was compared to the control data.

Results showed the fistula needle with ESIP was effective in reducing the incidence of needlesticks. No accidental needlesticks occurred during the evaluation period. These results indicate that this fistula needle with ESIP is effective in reducing the risk of exposure to bloodborne pathogens (BBP) and accidental needlesticks.

Healthcare workers using large hollow bore needles in hemodialysis and apheresis settings have a high risk of exposure to BBP. The hemodialysis population has a higher Hepatitis C (HCV) incidence than the general population. Non-guarded fistula needles account for almost half of all hemodialysis exposure events. The proper use of guarded fistula needle device to prevent needlestick injuries can reduce the risk of exposure to HBV, HCV, HIV and other BBP and ensure the safety of the frontline healthcare worker.

Full paper published in Nephrology News & Issues, May 2002. Request an official reprint from Medisystems.

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Not All Manufactured Blood Tubing Sets are Equal: Effects on QB and Kt/V
Ahmed J, Besarab A, Lubkowski T and Frinak S; ASAIO Journal, Vol 49, No 2: pp 198, 2003

We previously demonstrated that ReadySet® (RS) delivers ~ 40 ml/min more dialyzer blood flow (dQ) than CombiSet® (CS) tubing sets, increasing Kt/V ~ 0.1 (JASN 2002;13:412A). To confirm that such differences in dQ resulted from tubing characteristics, 23 patients whose access flow (QA) was >500 ml/min were studied. Patients were dialyzed for one week using CS followed by a week using RS tubing sets. During all 6 Rxs, QA, and dQ (ml/min, Transonic HD01® system), set blood flow (QB), pre-pump (PA) pressures [mm Hg] were measured at 10, 60, 120 min and 15 min prior to end of each Rx. Mid-week Rx blood H2O urea clearance (Curea ) [using dQ], URR, and Kt/V measurements were made. QB was pushed to the prescribed value or PA -280 mm Hg.

19 patients completed the study. Time averaged QB was equal (479 CS vs 477 RS). PA was more negative at all time points with RS vs CS (250- 260 vs 248-252). [QB-dQ] increased with Rx duration, from 8 to 19 ml/min using CS and from -4 to 6 ml/min using RS. Unpaired analysis revealed no differences for Curea (300 ±5 CS vs 308 ±4 RS), URR (0.70 ±0.01 vs 0.74 ±0.01); or Kt/V (1.50 ±0.05 vs 1.60 ±0.06). However, Curea by paired analysis was 7 ml/min greater with RS (p<0.006). Only 11 pts achieved QB 450 for all Rxs; Curea (+6.1 ml/min, P <0.02) was greater with RS. 9 pts achieved QB =500 for all Rx. URR (+3.5%, p=0.039) and Kt/V (+0.14, p= 0.04) were greater with RS than CS.

Differences in [QB-dQ] occur but are smaller with RS than CS and result in a higher Kt/V of up to 0.14 delivered . This difference may be important in any patient who runs high blood flows and has marginal Kt/V.

Review article published in Advances in Vascular Access, 2004. Request an official reprint from Medisystems.

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