Continuous arteriovenous hemodiafiltration

As demonstrated by the above examples, in CAVHD blood access is usually obtained through femotal catheters, the blood flow rate is not routinely measured and the dialysate flow rate is arbitratily set to 1 to 2 L/hr. In this way, the treatment proved genetally effective. However, sometimes problems were encountered. In some patients frequent clotting of dialyzers occurred, probably because blood flow rate was too low. Sometimes plasma urea levels did not come down as quickly as we had expected or levels of phosphate were found to become too low. There was vinually no insight in the determinants of transpon rates and the dialysate flow rate that is necessary. It was not known to what extent CAVHD treatment had influence on the disappearance rate of drugs. Therefore, in 1989 a study was begun of the detenninams of blood flow rate, ultrafiltration and solute transpon rate in CAVHD, so as to be able to optimize CAVHD treatmentThe aims of this srudy can be sUllllilalized as follows: 1. Analysis of the determinants of blood flow rate. The resistance to flow rate of catheters and dialyzers was studied and the influence of blood viscosity was analyzed. A method was investigated for the determination of blood flow rate by using a probe outside the blood line. 2. Analysis of the determinants of ultrafiltration and convective rranspon rate. The transmembrane pressure difference and the hydraulic permeability of dialyzers were determined as well as the change in hydraulic permeability over time. Funhermore, the 'sieving coefficients' were determined for a number of clinically relevant solutes. 3. Analysis of the determinants of the diffusive transpon rate. A mathematical model of combined convection and diffusion was developed and used to determine the diffusive mass transfer coefficiem of a number

An analytical solution to solute transport in continuous arterio-venous hemodiafiltration (CAVHD)

In conventional intermittent hemodialysis, the overall mass transfer coefficient (Ko) of a dialyser is mostly calculated at zero ultrafiltration and at relatively high dialysate flow rates. In continuous arterio-venous hemodiafiltration (CAVHD), the dialysate flow rates are low as comparable to the rates of ultrafiltration flows, making the dialysis treatment as slow as possible. Therefore the overall mass transfer coefficient (Kd) of a CAVHD hemofilter has to be calculated in the presence of ultrafiltration. A mathematical model of CAVHD is presented in order to calculate the diffusive mass transfer coefficient (Kd) for a solute when blood, filtrate and dialysate flow rates and solute concentrations are known. The ultrafiltration volume flux (Jv) is assumed to vary linearly along the axial direction of the hemofilter. The calculated mass transfer coefficient Kd shows that at high values of dialysate flow and low values of ultrafiltration, the overall mass transfer coefficient (Kd) of a CAVHD hemofilter equals mass transfer coefficient (Ko) of a dialyser in conventional intermittent hemodialysis. Also, the calculated mass transfer coefficient Kd shows no significant differences when the ultrafiltration volume flux is assumed to be constant along the length of the hemofilter if no backfiltration occurs in the hemofilter

Incidence of surgical site infections cannot be derived reliably from point prevalence survey data in Dutch hospitals

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Mortality associated with carbapenem-susceptible and Verona Integron-encoded Metallo-β-lactamase-positive Pseudomonas aeruginosa bacteremia

BACKGROUND: Studies on various Gram-negative bacteria suggest that resistance to carbapenem antibiotics is responsible for increased mortality in patients; however, results are not conclusive. We first assessed the 28-day in-hospital all-cause mortality in patients with Verona Integron-encoded Metallo-β-lactamase-positive Pseudomonas aeruginosa (VIM-PA) bacteremia compared to patients with VIM-negative, carbapenem-susceptible P. aeruginosa (CS-PA) bacteremia. Second, we identified determinants for mortality and survival. METHODS: All patients with a positive blood culture with VIM-PA or CS-PA between January 2004 and January 2016 were included. Kaplan-Meier survival curves were constructed, and survivors and non-survivors were compared on relevant clinical parameters using univariate analyses, and multivariable analyses using a Cox-proportional hazard model. RESULTS: In total, 249 patients were included, of which 58 (23.3%) died. Seventeen out of 40 (42.5%) patients with VIM-PA died, compared to 41 out of 209 (19.6%) patients with CS-PA (difference = 22.9%, P-value = 0.001). Assumed acquisition of the bacterium at the intensive care unit was significantly associated with mortality (HR = 3.32, 95%CI = 1.60-6.87), and having had adequate antibiotic therapy in days 1-14 after the positive blood culture was identified as a determinant for survival (HR = 0.03, 95%CI = 0.01-0.06). VIM-PA vs CS-PA was not identified as an independent risk factor for mortality. CONCLUSIONS: The crude mortality rate was significantly higher in patients with a VIM-PA bacteremia compared to patients with a CS-PA bacteremia; however, when analyzing the data in a multivariable model this difference was non-significant. Awareness of the presence of P. aeruginosa in the hospital environment that may be transmitted to patients and rapid microbiological diagnostics are essential for timely administration of appropriate antibiotics. Acquisition of P. aeruginosa should be prevented, independent of resistance profile

Brengt ultraschone lucht op de OK meer veiligheid?

• Het ‘Beheersplan luchtbehandeling voor de operatieafdeling’ (2005) beschrijft het beheer en het onderhoud van de luchtbehandelingsinstallatie. • In dit Beheersplan wordt een norm voorgesteld voor luchtkwaliteit op operatieafdelingen type 1, die is aangenomen door de Nederlandse Orthopedische Vereniging, doch niet door andere wetenschappelijke verenigingen. • De Britse studie die ten grondslag ligt aan de voorgestelde norm voor luchtkwaliteit van operatieafdelingen type 1 is van 1982, en onvoldoende gecorrigeerd voor profylaxe met antibiotica. Die profylaxe leidt op zich namelijk ook al tot minder postoperatieve wondinfecties. • Recentere studies naar ultraschone lucht op de operatieafdeling laten geen infectiepreventief effect zien. • Er ligt een ta

Survival of Staphylococcus aureus ST398 in the human nose after artificial inoculation.

There is evidence that MRSA ST398 of animal origin is only capable of temporarily occupying the human nose, and it is therefore, often considered a poor human colonizer.We inoculated 16 healthy human volunteers with a mixture of the human MSSA strain 1036 (ST931, CC8) and the bovine MSSA strain 5062 (ST398, CC398), 7 weeks after a treatment with mupirocin and chlorhexidine-containing soap. Bacterial survival was studied by follow-up cultures over 21 days. The human strain 1036 was eliminated faster (median 14 days; range 2-21 days) than the bovine strain 5062 (median 21 days; range 7-21 days) but this difference was not significant (p = 0.065). The bacterial loads were significantly higher for the bovine strain on day 7 and day 21. 4/14 volunteers (28.6%) showed elimination of both strains within 21 days. Of the 10 remaining volunteers, 5 showed no differences in bacterial counts between both strains, and in the other 5 the ST398 strain far outnumbered the human S. aureus strain. Within the 21 days of follow-up, neither human strain 1036 nor bovine strain 5062 appeared to acquire or lose any mobile genetic elements. In conclusion, S. aureus ST398 strain 5062 is capable of adequately competing for a niche with a human strain and survives in the human nose for at least 21 days