| 1. |
- Frykholm, Peter, 1961-, et al.
(författare)
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Preoperative fasting in children : review of existing guidelines and recent developments
- 2018
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Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 120:3, s. 469-474
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Forskningsöversikt (refereegranskat)abstract
- The current guidelines for preoperative fasting recommend intervals of 6, 4, and 2 h (6-4-2) of fasting for solids, breast milk, and clear fluids, respectively. The objective is to minimize the risk of pulmonary aspiration of gastric contents, but also to prevent unnecessarily long fasting intervals. Pulmonary aspiration is rare and associated with nearly no mortality in paediatric anaesthesia. The incidence may have decreased during the last decades, judging from several audits published recently. However, several reports of very long fasting intervals have also been published, in spite of the implementation of the 6-4-2 fasting regimens. In this review, we examine the physiological basis for various fasting recommendations, the temporal relationship between fluid intake and residual gastric content, and the pathophysiological effects of preoperative fasting, and review recent publications of various attempts to reduce the incidence of prolonged fasting in children. The pros and cons of the current guidelines will be addressed, and possible strategies for a future revision will be suggested.
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| 2. |
- Charlton, Jennifer R., et al.
(författare)
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Beyond the tubule : pathological variants of LRP2, encoding the megalin receptor, result in glomerular loss and early progressive chronic kidney disease
- 2020
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Ingår i: American Journal of Physiology - Renal Physiology. - : AMER PHYSIOLOGICAL SOC. - 1931-857X .- 1522-1466. ; 319:6, s. F988-F999
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic variants in the LRP2 gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal (DB/FOAR) syndrome. Because of the rarity of the syndrome, the long-term consequences of the tubulopathy on human renal health have been difficult to ascertain, and the human clinical condition has hitherto been characterized as a benign tubular condition with asymptomatic low-molecularweight proteinuria. We investigated renal function and morphology in a murine model of DB/FOAR syndrome and in patients with DB/FOAR. We analyzed glomerular filtration rate in mice by FETC-inulin clearance and clinically characterized six families, including nine patients with DB/FOAR and nine family members. Urine samples from patients were analyzed by Western blot analysis and biopsy materials were analyzed by histology. In the mouse model, we used histological methods to assess nephrogenesis and postnatal renal structure and contrast-enhanced magnetic resonance imaging to assess glomerular number. In megalin-deficient mice, we found a lower glomerular filtration rate and an increase in the abundance of injury markers, such as kidney injury molecule-1 and N-acetyl-11-n-glucosaminidase. Renal injury was validated in patients, who presented with increased urinary kidney injury molecule-1, classical markers of chronic kidney disease, and glomerular proteinuria early in life. Megalin-deficient mice had normal nephrogenesis, but they had 19% fewer nephrons in early adulthood and an increased fraction of nephrons with disconnected glomerulotubular junction. In conclusion, megalin dysfunction, as present in DB/FOAR syndrome, confers an increased risk of progression into chronic kidney disease.
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| 3. |
- Ekroth, M., et al.
(författare)
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Gradient zones in WC-Ti(C,N)-Co-based cemented carbides : Experimental study and computer simulations
- 2000
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Ingår i: Acta Materialia. - 1359-6454 .- 1873-2453. ; 48:9, s. 2177-2185
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Tidskriftsartikel (refereegranskat)abstract
- The formation of surface zones with a composition gradient during sintering of WC-Ti(C,N)-Co cemented carbides has been studied experimentally and by computer simulations. The microstructure has been investigated with SEM and EPMA. The simulations are based on a solution of the multicomponent diffusion equations, coupled with thermodynamic calculations using thermodynamic descriptions of the individual phases. The results from the simulations are in good agreement with the experimental results, indicating that diffusion and the thermodynamic properties are the two major factors that control the gradient structure formation.
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| 4. |
- Frykholm, Peter, et al.
(författare)
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Clinical guidelines on central venous catheterisation
- 2014
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 58:5, s. 508-524
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Forskningsöversikt (refereegranskat)abstract
- Safe and reliable venous access is mandatory in modern health care, but central venous catheters (CVCs) are associated with significant morbidity and mortality, This paper describes current Swedish guidelines for clinical management of CVCs The guidelines supply updated recommendations that may be useful in other countries as well. Literature retrieval in the Cochrane and Pubmed databases, of papers written in English or Swedish and pertaining to CVC management, was done by members of a task force of the Swedish Society of Anaesthesiology and Intensive Care Medicine. Consensus meetings were held throughout the review process to allow all parts of the guidelines to be embraced by all contributors. All of the content was carefully scored according to criteria by the Oxford Centre for Evidence-Based Medicine. We aimed at producing useful and reliable guidelines on bleeding diathesis, vascular approach, ultrasonic guidance, catheter tip positioning, prevention and management of associated trauma and infection, and specific training and follow-up. A structured patient history focused on bleeding should be taken prior to insertion of a CVCs. The right internal jugular vein should primarily be chosen for insertion of a wide-bore CVC. Catheter tip positioning in the right atrium or lower third of the superior caval vein should be verified for long-term use. Ultrasonic guidance should be used for catheterisation by the internal jugular or femoral veins and may also be used for insertion via the subclavian veins or the veins of the upper limb. The operator inserting a CVC should wear cap, mask, and sterile gown and gloves. For long-term intravenous access, tunnelled CVC or subcutaneous venous ports are preferred. Intravenous position of the catheter tip should be verified by clinical or radiological methods after insertion and before each use. Simulator-assisted training of CVC insertion should precede bedside training in patients. Units inserting and managing CVC should have quality assertion programmes for implementation and follow-up of routines, teaching, training and clinical outcome. Clinical guidelines on a wide range of relevant topics have been introduced, based on extensive literature retrieval, to facilitate effective and safe management of CVCs.
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| 5. |
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| 6. |
- Frykholm, Peter, 1961-, et al.
(författare)
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Pre-operative fasting in children : A guideline from the European Society of Anaesthesiology and Intensive Care
- 2022
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Ingår i: European Journal of Anaesthesiology. - : European Society of Anaesthesiology and Intensive Care. - 0265-0215 .- 1365-2346. ; 39:1, s. 4-25
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Tidskriftsartikel (refereegranskat)abstract
- Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents.We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force.Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a ‘light breakfast’ may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.
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| 7. |
- Frykholm, R., et al.
(författare)
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A new labyrinth factor for modelling the effect of binder volume fraction on gradient sintering of cemented carbides
- 2003
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 51:4, s. 1115-1121
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Tidskriftsartikel (refereegranskat)abstract
- To increase the cutting performance of WC-MC-Co cemented carbide tools, it is common to use a high temperature CVD process to coat them with thin wear resistant layers. During the process cracks are unavoidably introduced in the coating. To prevent crack propagation it is of interest to create a tough surface zone in the substrate, enriched in WC and binder phase. A way to create such a zone is to sinter a nitrogen-containing cemented carbide in a nitrogen free atmosphere. This formation of gradient structures has been extensively studied using microscopy and simulations, and it has been shown that the process is driven by diffusion in the binder phase. However, the diffusion paths are partly blocked by the dispersed particles. This effect can be formally handled by considering effective diffusivities by introducing a so-called labyrinth factor, lambda. In prior work it has been assumed that lambda =f(2) where f is the volume fraction of the binder. The validity of this assumption has been studied by simulations and experimental analysis of gradient sintered WC-Ti(C,N)-Co cemented carbides containing 5.0, 6.7, 10.0 and 20.0 vol% binder phase. It was found that by using the labyrinth factor lambda = f(2) instead of a better correspondence between experiments and simulations can be achieved.
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| 8. |
- Frykholm, R., et al.
(författare)
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Effect of cubic phase composition on gradient zone formation in cemented carbides
- 2001
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Ingår i: International journal of refractory metals & hard materials. - 0263-4368. ; 19:06-apr, s. 527-538
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Tidskriftsartikel (refereegranskat)abstract
- Cemented carbide cutting tool inserts with a surface zone depleted of hard cubic carbides and enriched in ductile binder phase have been studied experimentally using scanning electron microscopy (SEM), electron probe micro analysis (EPMA) and transmission electron microscopy (TEM). The results are compared with simulations based on a solution of the multicomponent diffusion equations, coupled with calculations using thermodynamic descriptions of the individual phases. The materials in the study are based on WC-Ti(C,N)-Co, WC-Ti(C,N)-NbC-Co and WC-Ti(C,N)-TaC-Co. The surface zone is formed by creating a gradient in nitrogen activity in the material, leading to an outward diffusion of N. Due to thermodynamical coupling between N and Ti, the outward diffusion of N will lead to an inward diffusion of Ti, and a surface zone depleted in cubic carbides is formed. Additions of elements like Ta or Nb will affect the width of the surface zone. A material with a Ta-containing cubic phase will have a narrower surface zone than a material with a Nb-containing cubic phase. Ta or Nb additions also affect the distribution of the different phases in and adjacent to the surface zone.
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| 9. |
- Leiter, Robert, et al.
(författare)
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Comparison of superimposed high-frequency jet ventilation with conventional jet ventilation for laryngeal surgery
- 2012
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Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 108:4, s. 690-697
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundNew ventilators have simplified the use of supraglottic superimposed high-frequency jet ventilation (SHFJVSG), but it has not been systematically compared with other modes of jet ventilation (JV) in humans. We sought to investigate whether SHFJVSG would provide more effective ventilation compared with single-frequency JV techniques.MethodsA total of 16 patients undergoing minor laryngeal surgery under general anaesthesia were included. In each patient, four different JV techniques were applied in random order for 10-min periods: SHFJVSG, supraglottic normal frequency (NFJVSG), supraglottic high frequency (HFJVSG), and infraglottic high-frequency jet ventilation (HFJVIG).Chest wall volume variations were continuously measured with opto-electronic plethysmography (OEP), intratracheal pressure was recorded and blood gases were measured.ResultsChest wall volumes were normalized to NFJVSG end-expiratory level. The increase in end-expiratory chest wall volume (EEVCW) was 239 (196) ml during SHFJVSG (P<0.05 compared with NFJVSG). EEVCW was 148 (145) and 44 (106) ml during HFJVSG and HFJVIG, respectively (P<0.05 compared with SHFJVSG). Tidal volume (VT) during SHFJVSG was 269 (149) ml. VT was 229 (169) ml (P=1.00 compared with SHFJVSG), 145 (50) ml (P<0.05), and 110 (33) ml (P<0.01) during NFJVSG, HFJVSG, and HFJVIG, respectively.Intratracheal pressures corresponded well to changes in both EEVCW and VT. All JV modes resulted in adequate oxygenation. However, PACO2was lowest during HFJVSG [4.3 (1.3) kPa; P<0.01 compared with SHFJVSG].ConclusionSHFJVSG was associated with increased EEVCW and VT compared with the three other investigated JV modes. All four modes provided adequate ventilation and oxygenation, and thus can be used for uncomplicated laryngeal surgery in healthy patients with limited airway obstruction.
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| 10. |
- Lindholm, L, et al.
(författare)
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Genetic re-targeting of adenovirus using a hyperstable scFv domain and an affibody (R) molecule against Her2/neu
- 2004
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Ingår i: Molecular Therapy. - : Elsevier BV. - 1525-0016 .- 1525-0024. ; 9, s. S250-S250
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Tidskriftsartikel (refereegranskat)abstract
- One important goal in gene therapy is to develop adenovirus (Ad) vectors that are genetically de-targeted as well as re-targeted. Genetic re-targeting of Ad using complex cell-binding ligands has previously not been possible. We have previously demonstrated that ligands for genetic re-targeting of adenoviruses must be able to fold correctly in the cytoplasm of virus producing cells, a milieu that is not conducive to the formation of disulphide bonds. Here, we describe functional Ad5 viruses with fibers and pIX capsid proteins genetically modified to contain two types of complex ligands. One is affibody® molecules, corresponding to small (6 kDa) binding proteins developed by combinatorial protein engineering using a single three-helix bundle staphylococcal protein A domain. The other type is hyperstable antibody scFv domains. The affibody molecule used here (ZH2N) is directed against Her2/neu. Recombinant viruses were constructed with ZH2N in three different positions: (i) at the C-terminus of shaft repeat 7 of de-knobbed fibers; (ii) at the C-terminus of pIX; and (iii) in the HI-loop of the fiber knob. Each of the viruses exhibited a characteristic phenotype regarding fiber content, growth and ability to infect Her2/neu expressing cells. In order to test the potentials of scFv liganded Ad vectors, a hyperstable antibody scFv against b-galactosidase was genetically incorporated into knobless fibers, in tandem with a mutated protein A domain reactive with IgG1 Fc that targeted the virus to Fc-expressing 293 cells. These fibers could be rescued into viable virions that retained the original antigen binding specificity of the scFv, demonstrating the basic potential of hyperstable scFvs for genetic re-targeting of Ad. Quite unexpectedly, the fiber content of Ad with knobless, scFv containing fibers was close to normal in contrast to other Ad with knobless fibers that generally has a much reduced fiber content. The hyperstable scFv was further fused to the C-terminus of the capsid protein pIX. The recombinant molecules could be rescued into viable viruses with wt fibers. The scFv retained its binding-specificity on the recombinant virions. The results demonstrate that, contrary to current beliefs, it is possible to construct Ad that genetically incorporates functional scFvs and other complex ligands into the virus fiber and pIX. The feasibility is demonstrated by the creation of different viruses that are re-targeted to Her2/neu. These viruses are currently in pre-clinical development.
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