Olfaction measure of asparagus cacosmia solute removal via low dialysate flow hemodialysis. William L. Peckham1; Anna L. Bennett2 Correspondence and offprint requests to: William L. Peckham, DSEN, Division of Blog Research, Seattle, WA USA. Email: bill.peckham @ yahoo.com Abstract Context. Humankind has long been vexed by cacosmia that accompanies natural renal output post asparagus consumption. A 50 year survey of nephrology peer reviewed literature indicates that questions surrounding hemodialysis removal of the asparagus cacosmia solute have not been addressed. Objective. To determine the efficacy of low dialysate flow hemodialysis in removing the asparagus cacosmia solute. Design, Setting, and Participants. Participants were recruited via email and at an informational table set up at the 2008 Stockton Asparagus Festival, California's largest charitable festival3. Complete study results will be presented at the 2009 Stockton Asparagus Festival poster session. Participants were categorized by renal function; those who were healthy or were found to have Chronic Kidney Disease 1 (CKD1) or 2 (CKD2) (GFR = 60->90mL/min/1.73 m2) were assigned the Urinator group (Ug). Those with CKD5 (GFR = <15 mL/min/1.73 m2 or post transplant) were assigned to the Dialyzor group (Dg). The Dg group was further distinguished as managing CKD5 with dialysis (DgD) or managing CKD5 with renal allograft (DgT). All DgD participants managed their CKD5 with home hemodialysis using the NxStage cycler and dialysate flow rates 115mm/min +/-25ml/min. Each group (Ug (n=30), DgD (n=16), DgT (n=10)) were randomized into a control group which ingested 500g (+/-50g) of steamed Asparaguisetm 4 (A1), or the study group which ingested 500g (+/- 50g) of steamed Stockton Valley Asparagus (A2). Participants were instructed to fast, ingesting only water for 6 hours prior to initiating the study. The DgT and Ug cohorts were instructed to void before eating and then to collect 100ml samples during the three post ingestion voiding episodes. DgD were instructed to eat their study material 2 hours prior to their dialysis treatment and to collect 100ml dialysate samples every 30 minutes commencing 10 minutes after initiation of treatment. Main Outcome Measures. To establish the odor concentration, an olfactometer was used which employed a panel of test persons. A sample of Ug natural output post asparagus ingestion and an odor-free gas (as a reference) were presented from sniffing ports to a group of panelists (n=10; the panelists must fulfill certain requirements, for example regarding their sensitivity of odor perception; the gas used to verify this requirement was n-Butanol). In comparing the gases emitted from each port, the panelists were asked to report the presence of odor. The gas-diluting ratio was then decreased by a factor of 1.4 or two (i.e. the concentration is increased accordingly). The panelists were then asked to repeat their judgment. This continued for a number of dilution levels. The responses of the panelists over a range of dilution settings are used to calculate the concentration of the odor in terms of European Odor Units (OUE/m3). Results. The Ug A1 cohort output was measured to be OUE=2 which is within the margin of error for human urine, and stayed level across all samples. The Ug A2 cohort's output measured OUE=4 on the first sample, OUE=3 on the second sample before plateauing at the OUE=2 baseline on subsequent sampling. The DgT A1 cohort and DgT A2 cohort results matched those of the paired Ug cohorts. The DgD A1 cohort output was measured at OUE=1 which is within the margin of error for post use dialysate, and stayed level across all samples. The DgD A2 cohort's output measured OUE=3 on the first, second and third dialysate sample, the forth and fifth samples measured OUE=2, the 6th and subsequent samples were measured to be at the OUE=1 baseline. Conclusion. Asparagus cacosmia solutes are removed during hemodialysis using low dialysate flow rates. The study was under powered to distinguish removal across varying blood flows and dialysate flows. Phase 2 of the study will look to confirm asparagus cacosmia solute removal via peritoneal dialysis and look in more detail at asparagus cacosmia solute removal as a measure of dialysis adequacy, confirming initial results that correlate OUE to adequacy targets as closely as Kt/V. Phase 2 should confirm that a post dialysate OUE=1 equates to a Kt/V = 1.2. Author Affiliations and Disclosures: 1Dialysis from the Sharp End of the Needle and Carpenter's Union, Seattle Local 131; disclosed conflicts of interest, the author grows asparagus in his home garden. 2Dialysis from the Sharp End of the Needle and 1199 SEIU; disclosed conflicts of interest - too many to elaborate. 3This study would like thank the Stockton Asparagus Festival for funding; the authors report they declined a research grant offered by the Salt Institute after DESN's Internal Review Board determined an excessive use of NaCl as required by the grantor would be harmful to the health of the participants. 4This study would like thank Asparaguisetm for funding; Asparaguisetm the soy based asparagus replacement that tastes and looks like asparagus but dose not produce the asparagus cacosmia solute. Keywords: Asparagus Odor, Asparagus Pee, Hemodialysis Received for publication: 30. 3.09 Accepted in revised form: 31. 3.09
Should dialysis units include identification and training of volunteer olfactometer panels as part of their emergency preparation?
Who can smell asparagus in their urine?
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