| 1. |
- Brauer, Kirk I, et al.
(författare)
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Hypoproteinemia does not alter plasma volume expansion in response to a 0.9% saline bolus in awake sheep
- 2010
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Ingår i: CRITICAL CARE MEDICINE. - : Williams and Wilkins. - 0090-3493 .- 1530-0293. ; 38:10, s. 2011-2015
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To test the hypothesis that hypoproteinemia reduces plasma volume expansion produced by a bolus of crystalloid solution given to awake sheep. Design: Prospective and observational. Setting: Laboratory. Subjects: Five female merino sheep (n = 5) weighing 37 +/- 3 kg were anesthetized. Interventions: Each animal was subjected to a 5-day test period: day 1: 50 mL/min 0.9% saline infusion over 20 mins. Days 2-4: daily plasmapheresis and replacement of the shed plasma with 6 L of 0.9% saline were performed in increments. Measurements and Main Results: Fractional plasma volume expansion after rapid infusion of saline on days 1 and 5 was calculated from changes in hemoglobin concentration. There was a significant reduction in total plasma protein concentration after plasmapheresis (p andlt; .05). Colloid osmotic pressures were also significantly lowered (p andlt; .05). A crystalloid infusion of 0.9% saline did not alter any of these values compared with baseline. The hemodynamic measurements did not show significant differences between the experiments. The plasma volume expansion reached approximately 20% at the end of infusion and stayed at 10-15% during the experiments. No difference was found in plasma volume expansion produced by a bolus of 50 mL/min of 0.9% in the hypoproteinemic state when compared with the euproteinemic state (p = .61). No difference in cumulative urinary output was found between the two states. Conclusions: In contrast to our hypothesis, severe acute hypoproteinemia does not reduce plasma volume expansion in response to 50 mL/min 0.9% saline infusion in nonspleenectomized sheep when compared with the resultant plasma volume expansion after a 50 mL/min of 0.9% infusion in the euproteinemic state.
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| 2. |
- Rodhe, Peter M
(författare)
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Mathematical modelling of clinical applications in fluid therapy
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: This thesis presents a new application of fluid kinetic analysis using mathematical tools to evaluate fluid therapy problems. Several models were developed to mathematically handle fluid distribution concerning bleeding and anaesthesia, arterio-venous differences in plasma dilution, peripheral fluid accumulation and differences in fluid distribution among young and elderly patients. Non-linear regression models were used to fit equations to sampled haemoglobin data. Methods: I: Six chronically instrumented sheep were subjected to four randomly ordered experiments while conscious or during anesthesia with isoflurane. After plasma volume measurement 15% or 45% of the blood volume was withdrawn. To quantify transcapillary refill, mass balance and kinetic calculations utilized repeated measurements of haemoglobin concentration. II: Fifteen volunteers received an intravenous (iv) infusion of 15 mL/kg of lactated Ringer s solution during 10 min. Simultaneous arterial and venous blood haemoglobin (Hb) samples were obtained and Hb concentrations measured. III: Ten healthy female non-pregnant volunteers participated. The protocol included an infusion of acetated Ringer s solution, 25 ml/kg over 30 minutes. Blood samples were repeatedly. A standard bladder catheter was continuously monitoring urine excretion. Plasma dilution, peripheral accumulation and urine output were modelled simultaneously. IV: Twenty four volunteers participated. Two age groups, a young group (age 18-25) and an elderly group (age 70-90) were formed. On separate occasions, the subjects in both groups were given a crystalloid 25 mg/ml glucose solution, either orally (ORAL) or intravenously (IV) in a crossover design with at least two weeks in between. On each occasion, the subjects got 7 ml/kg of the crystalloid solution during 15 minutes. Results: I: After either normotensive or hypotensive hemorrhage, transcapillary refill occurred more rapidly during the first 40 min than during the next 140 min (p < 0.001). In conscious sheep, at 180 min, 57% and 42% of the bled volume had been restored after normotensive and hypotensive hemorrhage, respectively, in contrast to only 13% and 27% (p < 0.001) in isoflurane-anesthetized sheep. Using parameters derived from kinetic analysis, simulations illustrate that both the hydrostatic and colloid osmotic forces are weaker in the presence of isoflurane than in the awake state. II: The AV difference in plasma dilution was only positive during the infusion and for 2.5 min thereafter, which represents the period of net flow of fluid from plasma to tissue. Kinetic analysis showed that volume expansion of the peripheral fluid space began to decrease 14 min (arterial blood) and 20 min (venous blood) after the infusion ended. III: Maximum urinary output rate was found to be 19 (13 31) ml/min. The subjects were likely to accumulate three times as much of the infused fluid peripherally as centrally; Elimination efficacy, Eeff, was 24 (5 35) and the basal elimination kb was 1.11 (0.28 2.90). The total time delay Ttot of urinary output was estimated to 17 (11 - 31) min. IV: The lag-time of glucose given orally was estimated to be 17 (8 25) min for the younger group and 18 (13 22) min for the elderly. For fluid, the lag-time was estimated to 29 (21 - 34) min for the younger and 25 (16 39) min for the elderly. Conclusions: Final conclusion is that mathematical modelling of clinical applications can be done in several different clinical settings and will improve the understanding of fluid distribution. It is possible to continuously model fluid behaviour in the body as seen in Papers II-III. This should enhance the understanding of accumulating oedema in the body which is an apparent problem for all clinicians.
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| 3. |
- Sundvall, Pär-Daniel, et al.
(författare)
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Antimicrobial resistance in urinary pathogens among Swedish nursing home residents remains low: a cross-sectional study comparing antimicrobial resistance from 2003 to 2012
- 2014
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Ingår i: BMC Geriatrics. - : Springer Science and Business Media LLC. - 1471-2318. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are several risk factors for the colonisation, infection and spreading of antibiotic resistant bacteria among elderly residents of nursing homes. An updated estimate of the native prevalence of antimicrobial resistance in uropathogens among Swedish nursing home residents is needed. Methods: Urine specimens were collected for culture and antimicrobial susceptibility testing against mecillinam, ampicillin, cefadroxil, trimethoprim, nitrofurantoin and quinolones from the residents of 32 and 22 nursing homes, respectively. The residents were capable of providing a voided urine sample in 2003 and 2012. In 2012 urine specimens were also collected from residents with urinary catheters. Any antibiotic treatment during the previous month was registered in 2003 as well as hospitalisation and any antibiotic treatment during the previous six months in 2012. Results: The proportion of positive urine cultures was 32% (207/651) in voided urine specimens in 2003, 35% (147/421) in 2012, and 46% (27/59) in urine samples from catheters in 2012. Escherichia coli (E. coli) was the most commonly occurring bacteria. Resistance rates in E. coli (voided urine specimens) in 2012 were; ampicillin 21%, trimethoprim 12%, mecillinam 7.7%, ciprofloxacin 3.4%, cefadroxil 2.6% and nitrofurantoin 0.85%. There were no significant changes in the average resistance rates in E. coli for antibiotics tested 2003-2012. In 2012, two isolates of E. coli produced extended spectrum beta-lactamase enzymes (ESBL) and one with plasmid mediated AmpC production. Any antibiotic treatment during the previous month increased the risk for resistance in E. coli, adjusted for age and gender; for mecillinam with an odds ratio (OR) of 7.1 (2.4-21; p = 0.00049), ampicillin OR 5.2 (2.4-11; p = 0.000036), nalidixic acid OR 4.6 (1.4-16; p = 0.014) and trimethoprim OR 3.9 (1.6-9.2; p = 0.0023). Hospitalisation during the previous six months increased the risk for antibiotic resistance in E. coli to ampicillin, ciprofloxacin and any antimicrobial tested, adjusted for age, gender and antibiotic treatments during the previous six months. Conclusions: The average rates of antimicrobial resistance were low and did not increase between 2003 and 2012 in E. coli urinary isolates among Swedish nursing home residents. Antibiotic treatment during the previous month and hospitalisation during the previous six months predicted higher resistance rates.
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| 4. |
- Sundvall, Pär-Daniel, et al.
(författare)
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Interleukin-6 concentrations in the urine and dipstick analyses were related to bacteriuria but not symptoms in the elderly: a cross sectional study of 421 nursing home residents
- 2014
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Ingår i: BMC Geriatrics. - : Springer Science and Business Media LLC. - 1471-2318. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Up to half the residents of nursing homes for the elderly have asymptomatic bacteriuria (ABU), which should not be treated with antibiotics. A complementary test to discriminate between symptomatic urinary tract infections (UTI) and ABU is needed, as diagnostic uncertainty is likely to generate significant antibiotic overtreatment. Previous studies indicate that Interleukin-6 (IL-6) in the urine might be suitable as such a test. The aim of this study was to investigate the association between laboratory findings of bacteriuria, IL-6 in the urine, dipstick urinalysis and newly onset symptoms among residents of nursing homes. Methods: In this cross sectional study, voided urine specimens for culture, urine dipstick and IL-6 analyses were collected from all residents capable of providing a voided urine sample, regardless of the presence of symptoms. Urine specimens and symptom forms were provided from 421 residents of 22 nursing homes. The following new or increased nonspecific symptoms occurring during the previous month were registered; fatigue, restlessness, confusion, aggressiveness, loss of appetite, frequent falls and not being herself/himself, as well as symptoms from the urinary tract; dysuria, urinary urgency and frequency. Results: Recent onset of nonspecific symptoms was common among elderly residents of nursing homes (85/421). Urine cultures were positive in 32% (135/421), Escherichia coli was by far the most common bacterial finding. Residents without nonspecific symptoms had positive urine cultures as often as those with nonspecific symptoms with a duration of up to one month. Residents with positive urine cultures had higher concentrations of IL-6 in the urine (p < 0.001). However, among residents with positive urine cultures there were no differences in IL-6 concentrations or dipstick findings between those with or without nonspecific symptoms. Conclusions: Nonspecific symptoms among elderly residents of nursing homes are unlikely to be caused by bacteria in the urine. This study could not establish any clinical value of using dipstick urinalysis or IL-6 in the urine to verify if bacteriuria was linked to nonspecific symptoms.
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| 5. |
- Webb, Jim, et al.
(författare)
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An Assessment of the Variation of Manure Nitrogen Efficiency throughout Europe and an Appraisal of Means to Increase Manure-N Efficiency
- 2013
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Ingår i: Advances in Agronomy. ; 119, s. 371-442
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Tidskriftsartikel (refereegranskat)abstract
- Using the nitrogen (N) in organic manures more effectively reduces losses to the environment. A requirement to take allowance of the N conserved by reduced ammonia (NH3)-emission techniques would increase manure-N efficiency by up to 15%. Covering manure stores and land application of slurry by injection beneath the soil surface and by rapid incorporation of both slurries and solid manures into uncropped soil reduce NH3 emissions. Injection of cattle slurry also reduces N immobilization compared with application methods, which mix the slurry with soil and increases manure-N efficiency by ca 10-15%. In growing cereals, NH3 emissions can be reduced by band spreading within the canopy. Anaerobic digestion of slurry may also increase manure-N availability in the season of application by 10-20%, compared with undigested slurry. Slurry acidification may increase manure-N efficiency by 35-65% by reducing total NH3 losses by 70% compared with unacidified slurry stored without cover and not incorporated after spreading. To fully utilize the fertilizer value of manure-N, uptake over more than 1 year needs to be accounted for. This is particularly important for solid manures which provide less-available N in the season after application than slurries but release more N to crops in subsequent years. Using manure-N as a sole N source may limit overall manure-N efficiency. Applying manures at reduced rates over a larger crop area, using N fertilizer at times when crop recovery of manure-N may be limited, may give the greatest overall manure-N efficiency.
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