In Vitro Comparative Assessment of Mechanical Blood Damage Induced by Different Hemodialysis Treatments.

Gradual deterioration of red blood cells (RBCs) due to mechanical stress (chronic hemolysis) is unavoidable during treatments that involve extracorporeal blood circulation, such as hemodialysis (HD). This effect is generally undetectable and does not generate any acute symptoms, but it leads to an increase in plasma free hemoglobin (fHb). There are no absolute safety levels for fHb increase, indicating the need for an empirical evaluation using comparative testing. The increase in fHb levels was investigated in vitro by applying double-needle double-pump HD (HD-DNDP), a new modality in which arterial and venous pumps both run continuously. fHb was measured during typical and worst-case simulated dialysis treatments (double-needle single-pump HD [HD-DNSP], hemodiafiltration [HDF-DN], single-needle double-pump HD [HD-SNDP], and HD-DNDP) performed in vitro using bovine blood for 4 h. Hemolysis-related indices (fHb%; index of hemolysis, IH; and normalized IH) were calculated and used for comparison. The increase in fHb during either HDF-DN or HD-SNDP with Artis and AK200 dialysis machines was similar, while the fHb at the maximum real blood flow rate (Qbreal ) at the completion of the HD-DNDP treatment on Artis was higher than that for HD-DNSP using a Phoenix dialysis machine (fHb% = 1.24 ± 0.13 and 0.92 ± 0.12 for the Artis machine with HD-DNDP at Qbreal = 450 mL/min and Phoenix with HD-DNSP at Qbreal = 500 mL/min, respectively). However, the fHb levels increased linearly, and no steep changes were observed. The increases observed during HD-DNDP were the same order of magnitude as those for widely used bloodlines and treatment modes for delivering dialysis treatments. The observed results matched literature findings, and thus the measured fHb trends are not predicted to have clinical side effects. HD-DNDP treatment with Artis does not merit any additional concern regarding mechanical stress to RBCs compared with that observed for routinely used dialysis treatments, bloodlines and machines. Although the in vitro measurement of the fHb increase in bovine blood does not allow a prediction of the absolute level of blood mechanical damage or the possible effects in humans, such measurements are valuable for assessing hemolytic harm by performing tests comparing the proposed treatment with existing devices.

Knowing what we do and doing what we should: quality assurance in hemodialysis.

An international group of around 50 nephrologists and scientists, including representatives from large dialysis provider organisations, formulated recommendations on how to develop and implement quality assurance measures to improve individual hemodialysis patient care, population health and cost effectiveness. Discussed were methods thought to be of highest priority, those clinical indicators which might be most related to meaningful patient outcomes, tools to control treatment delivery and the role of facilitating computerized expert systems. Emphasis was given to the use of new technologies such as measurement of online dialysance and ways of assessing fluid status. The current evidence linking achievement of quality criteria with patient outcomes was reviewed. This paper summarizes useful processes and quality measures supporting quality assurance that have been agreed across the expert panel. It also notes areas where more understanding is required.

Multidisciplinary evaluation for severity of hazards applied to hemodialysis devices: an original risk analysis method.

BACKGROUND AND OBJECTIVES: Risk analysis for medical devices is a crucial process to grant adequate levels of safety. Identification of device exposure-related hazards is one of the main objectives. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Hazard analysis for hemodialysis devices has been performed by a multidisciplinary team involving engineers and clinical experts. A potential harm list was identified from clinical and technical experience, postproduction information, and literature. Various hazardous situations (circumstances when the use of the dialysis device may lead to described harms) were described. Such hazardous situations were correlated to the extent of the deviation of a specific device parameter from expected ranges. The clinical severity that was relevant to any specific harm was categorized for each hazardous situation using a descriptive and numerical scale with five levels (from negligible [i.e., discomfort only] to catastrophic [i.e., potentially lethal]). RESULTS: Harms in which the deviation of a parameter strictly coincides with the clinically measured effect on the patient are defined as "direct." Otherwise, when another clinical parameter must be involved to quantify severity, the related harm is considered "indirect." Two complete examples of multidisciplinary evaluation for severity of hazards (MESH) are given for a direct harm (air embolism) and for an indirect harm (hypothermia). For other harms, the maximum value of severity involved is provided. CONCLUSIONS: MESH represents a possible example of risk management for dialysis equipment in which, although the manufacturer is directly responsible, a multidisciplinary task force may contribute to a better link between engineering and clinical perspectives.

Monitor turnaround time and time efficiency in hemodialysis delivery--a global comparison.

BACKGROUND/AIMS: Increasing cost pressure has forced shortening of dialysis treatments. The aim of this study was to benchmark the hemodialysis (HD) delivery monitor turnaround time and time efficiency in a global comparison. METHODS: 683 HD deliveries in 26 Gambro Healthcare clinics in Europe, Taiwan and the USA were assessed using the Treatment Mapping methodology. RESULTS: Consolidated mean monitor turnaround time was 324.4 min. On average, 69% consisted of the HD treatment and 31% (102.8 min) of other activities: monitor preparation, monitor disinfection and monitor waiting--roughly one third each. USA had the shortest monitor turnaround, dialysis treatment and disinfection times. However, time efficiency--the percentage of monitor turnaround time on dialysis--was the lowest in the USA (68 vs. 69 and 74% in Europe and Taiwan) as monitor preparation, undress and waiting were the longest in USA. CONCLUSION: A monitor/disposable design to minimize time for preparation, undress and disinfection would reduce the cost of operational time without compromising quality.

Treatment mapping--a systematic methodology to assess quality, efficiency and variability in the hemodialysis delivery process.

BACKGROUND/AIMS: Radical thinking about the design of industrial processes has greatly improved the quality and efficiency of manufacturing and services. Applying similar methods in healthcare to deliver quality care at lower costs would be valuable. METHODS: We have developed and validated a methodology--Treatment Mapping--to analyze the hemodialysis (HD) delivery as an operational process. RESULTS: The methodology was well applicable in the 26 Gambro Healthcare clinics studied (Europe, Taiwan, USA). Monitor process, patient process and dialysis treatment times (mean +/- SD) were 324.4 +/- 46.0, 272.2 +/- 34.5 and 221.6 +/- 28.8 min, respectively. In general, significant variability in process cycle times was found in the clinics studied. CONCLUSION: HD delivery is a complex process influenced by patient characteristics, monitor/disposables design, staff skills and clinic practices and physical layout. The Treatment Mapping methodology is a useful tool to analyze the HD delivery from a process quality and process operational perspective.

Clinical use of high-efficiency hemodialysis treatments: long-term assessment.

Significant technological changes in blood flow rate, dialyzer membrane permeability, bicarbonate dialysate, and ultrafiltration-controlled delivery systems permitted the implementation of 3 modifications to conventional hemodialysis as follows: high-efficiency hemodialysis (HEHD), high-flux hemodialysis (HFHD), and double-high-flux hemodiafiltration (HDF). The impact of these techniques on the quantity of the treatment administered and treatment time were assessed. One hundred and eighty-three patients were enrolled over 6 years. Monthly Kt/Vurea and dialysis treatment time were compared among the treatment techniques. In vivo extracorporeal clearances were measured for the dialyzers used. In vivo kinetically derived effective dialyzer clearances were calculated from Kt/V. Patient survival and standardized mortality ratio (SMR) were determined for each treatment modality. Treatment time averaged 192+/-28, 176+/-29, and 159+/-32 min, Kt/Vurea averaged 1.33+/-.34, 1.29+/-.30, 1.41+/-.32, and in vivo delivered urea clearance averaged 222+/-51, 272+/-34, and 333+/-43 mL/min for HEHD, HFHD, and HDF, respectively. These results were achieved even in patients with body weights in excess of 80 kgs. Net ultrafiltration rate during the treatment reached 20-30 mL/min, without clinical untoward effects. Blood flow rate ranged between 450-650 mL/min in all patients. Kaplan-Meier Survival analysis yielded a significant difference when high-efficiency treatments were compared with USRDS outcomes. Standardized mortality ratio analysis showed significance for only HDF vs. USRDS. High-efficiency treatments can provide the same quantity of treatment in a shorter period of time without affecting mortality. The increased spectrum of solutes removal provided by HFHD and HDF may be a further advantage of these treatments.

Discrepancies between adequacy goals in peritoneal dialysis: role of gender.

BACKGROUND: The National Kidney Foundation-Dialysis Outcome Quality Initiative (NKF-DOQI) recommends a weekly creatinine clearance (CrCl) of 60 L/wk/1.73 m2 or greater and a Kt/V of 2.0 or greater as peritoneal dialysis (PD) adequacy standards. It has been described that approximately one quarter of patients may have discrepancies between these goals. The purpose of this study is to identify associated factors in patients reaching both criteria, none, or only weekly Kt/V, where K is clearance, t is time, and V is volume. METHODS: We studied 64 patients and their adequacy results in a cross-sectional analysis. Patients were divided in three groups. Group 1 reached both weekly Kt/V and CrCl criteria. Group 2 did not reach either criteria. Group 3 reached only the weekly Kt/V criterion. A new weekly Kt/V also was calculated, assigning to all patients a male V. One patient who met only the CrCl criterion was excluded. RESULTS: Groups 2 and 3 had significantly less residual renal function (RRF) than group 1 (residual CrCl, 5.50 and 1.33 versus 37.3 L/wk/1.73 m2, respectively; P < 0.001). Other differences, such as age, weight, peritoneal membrane transport, nutritional parameters, or number of patients with diabetes, were not significantly different. Group 3 made up 19% of patients and was predominantly females. Conversely, group 2 was predominantly males. Using a male V, we obtained a weekly Kt/V below the NKF-DOQI recommendations for group 3 (1.9 versus 2.2; P < 0.05). CONCLUSION: Conservation of RRF was the main factor in reaching both PD adequacy criteria. Discrepancies were frequent, accounting for 19% of our population. Female gender explained why patients reached weekly Kt/V only. This difference disappeared when we calculated Kt/V using a male V.