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Matthew L. Costa - One of the best experts on this subject based on the ideXlab platform.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an ‘open-cell’ Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) – a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients’ DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of –3.9 points (95% confidence interval –8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an 'open-cell' Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) - a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients' DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of -3.9 points (95% confidence interval -8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 73. See the NIHR Journals Library website for further project information.

  • effect of negative pressure wound therapy vs standard wound management on 12 month disability among adults with severe open fracture of the lower limb the wollf randomized clinical trial
    JAMA, 2018
    Co-Authors: Julie Bruce, Elizabeth Tutton, Stavros Petrou, Juul Achten, Sarah E Lamb, Matthew L. Costa
    Abstract:

    Importance Open fractures of the lower limb occur when a broken bone penetrates the skin. There can be major complications from these fractures, which can be life-changing. Objectives To assess the disability, rate of deep infection, and quality of life in patients with severe open fracture of the lower limb treated with negative pressure wound therapy (NPWT) vs standard wound management after the first surgical debridement of the wound. Design, Setting, and Participants Multicenter randomized trial performed in the UK Major Trauma Network, recruiting 460 patients aged 16 years or older with a severe open fracture of the lower limb from July 2012 through December 2015. Final outcome data were collected through November 2016. Exclusions were presentation more than 72 hours after injury and inability to complete questionnaires. Interventions NPWT (n = 226) in which an open-cell Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump, creating a partial vacuum over the dressing, vs standard dressings not involving application of negative pressure (n = 234). Main Outcomes and Measures Disability Rating Index score (range, 0 [no disability] to 100 [completely disabled]) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. Secondary outcomes were complications including deep infection and quality of life (score ranged from 1 [best possible] to −0.59 [worst possible]; minimal clinically important difference, 0.08) collected at 3, 6, 9, and 12 months. Results Among 460 patients who were randomized (mean age, 45.3 years; 74% men), 88% (374/427) of available study participants completed the trial. There were no statistically significant differences in the patients’ Disability Rating Index score at 12 months (mean score, 45.5 in the NPWT group vs 42.4 in the standard dressing group; mean difference, −3.9 [95% CI, −8.9 to 1.2];P = .13), in the number of deep surgical site infections (16 [7.1%] in the NPWT group vs 19 [8.1%] in the standard dressing group; difference, 1.0% [95% CI, −4.2% to 6.3%];P = .64), or in quality of life between groups (difference in EuroQol 5-dimensions questionnaire, 0.02 [95% CI, −0.05 to 0.08]; Short Form–12 Physical Component Score, 0.5 [95% CI, −3.1 to 4.1] and Mental Health Component Score, −0.4 [95% CI, −2.2 to 1.4]). Conclusions and Relevance Among patients with severe open fracture of the lower limb, use of NPWT compared with standard wound dressing did not improve self-rated disability at 12 months. The findings do not support this treatment for severe open fractures. Trial Registration isrctn.org Identifier:ISRCTN33756652

J Jaap C Schouten - One of the best experts on this subject based on the ideXlab platform.

  • gas holdup of rotating Foam reactors measured by γ tomography effect of Solid Foam pore size and liquid viscosity
    Aiche Journal, 2013
    Co-Authors: R Tschentscher, Andre Bieberle, Markus Schubert, Uwe Hampel, J Van Der Schaaf, Alexander T Nijhuis, J Jaap C Schouten
    Abstract:

    Rotating Foam reactors have already shown to give high mass transfer rates compared to stirred tank reactors. For a deeper insight into the hydrodynamics of these reactors, the hydrodynamics of rotating Foam reactors were studied using γ-ray tomography. The two-phase flow through the Foam block stirrer is mainly influenced by the Solid Foam pore size and the liquid viscosity. For low viscosity, the optimal Foam block pore size was identified in the range between 10 and 20 pores per inch (ppi). With smaller pore size, the gas holdup inside the Foam block strongly increases due to bubble entrapment. For higher viscosity, pore sizes larger than 10 ppi have to be used to achieve a sufficient liquid flow rate through the Foam block to avoid a strong gradient over the reactor height. The effect of the hydrodynamics on the gas–liquid and liquid–Solid mass transfer and the reactor performance are discussed. © 2012 American Institute of Chemical Engineers AIChE J, 59: 146–154, 2013

  • gas holdup of rotating Foam reactors measured by γ tomography effect of Solid Foam pore size and liquid viscosity
    Aiche Journal, 2013
    Co-Authors: R Tschentscher, Andre Bieberle, Markus Schubert, Uwe Hampel, Alexander T Nijhuis, John Van Der Schaaf, J Jaap C Schouten
    Abstract:

    Rotating Foam reactors have already shown to give high mass transfer rates compared to stirred tank reactors. For a deeper insight into the hydrodynamics of these reactors, the hydrodynamics of rotating Foam reactors were studied using -ray tomography. The two phase flow through the Foam block stirrer is mainly influenced by the Solid Foam pore size and the liquid viscosity. For low viscosity, the optimal Foam block pore size was identified in the range between 10 and 20 ppi. With smaller pore size, the gas-holdup inside the Foam block strongly increases due to bubble entrapment. For higher viscosity, pore sizes larger than 10 ppi have to be used in order to achieve a sufficient liquid flow rate through the Foam block to avoid a strong gradient over the reactor height. The effect of the hydrodynamics on the gas-liquid and liquid-Solid mass transfer and the reactor performance are discussed.

  • rotating Foam stirrer reactor effect of catalyst coating characteristics on reactor performance
    Industrial & Engineering Chemistry Research, 2011
    Co-Authors: Maria A Leon, J Van Der Schaaf, R Tschentscher, Alexander T Nijhuis, J Jaap C Schouten
    Abstract:

    Rotating Foam stirrer reactors have a promising application in multiphase reactions. In this reactor, highly porous open-celled materials, Solid Foams, are used both as a catalyst support and as stirrer blades. One of the advantages of such a Foam stirrer is easy catalyst handling. This paper presents a preparation method for catalysts on Solid Foam supports. The performance of the alumina Foam catalysts is tested in the hydrogenation of a functionalized alkyne. A stable and homogeneous catalytic coating was deposited on aluminum Foams by a combination of anodization and wash coating using the slurry method. Anodization produced a rough and porous material that improved the adhesion of the catalytic coating. The use of a slurry with a bimodal particle size distribution increased the catalytic coating stability. The mass loss of the catalytic coating after applying ultrasonic vibrations was less than 10 wt %, which indicates a good adhesion. A high specific surface area was achieved by increasing the Foam ...

  • liquid Solid mass transfer in agitated slurry reactors and rotating Solid Foam reactors
    Industrial & Engineering Chemistry Research, 2010
    Co-Authors: R Tschentscher, T A Nijhuis, J Van Der Schaaf, R J P Spijkers, J Jaap C Schouten
    Abstract:

    The liquid−Solid mass transfer rate is studied for two three-phase reactor configurations, a stirred reactor and a rotating Solid Foam reactor, using the dissolution of copper by potassium dichromate as a model reaction. For the stirred reactor consisting of a Rushton stirrer and a slurry with small particles, the particle density has a large influence on the liquid−Solid mass transfer rate. Heavy particles show high slip velocities, as their path is less influenced by the liquid turbulence. Furthermore, the mass transfer is enhanced by neighboring particles passing each other. In the case of Solid copper particles, a kLS value of 3 × 10−3 ms−1 was observed. For particles having a density comparable to industrial catalyst supports, the kLS value is 1 order of magnitude lower. For the rotating Foam block stirrer also, high kLS values of 2.5 × 10−3 ms−1 could be achieved due to the high liquid velocity along the Foam struts. The influence of several parameters on the hydrodynamics and the liquid−Solid mass ...

  • gas liquid mass transfer in rotating Solid Foam reactors
    Chemical Engineering Science, 2010
    Co-Authors: R Tschentscher, T A Nijhuis, J Van Der Schaaf, Bernhard Kuster, J Jaap C Schouten
    Abstract:

    Abstract Three-phase reactor designs based on rotating Solid Foams for the application in the fine chemical industry are developed. The aim is to use Solid Foams both as a catalyst support and stirrer in order to mix the gas and liquid phases and create fine gas bubbles. Gas–liquid mass transfer data are presented for different Solid Foam stirrer configurations and compared to an optimized Rushton stirrer. Solid Foam stirrers were developed in a blade and a block design. Both Foam reactor designs work at stirring rates below 600 rpm. Using the Foam blade design, gas bubbles are mainly created by the turbulence at the gas–liquid interface. Large bubbles are broken up by the Foam blades. Using a Foam block design, rotation leads to the structurization of the reactor volume into sections strongly differing in gas holdup, flow behavior and bubble size distribution. This results in a gas–liquid mass transfer, which is 50% higher than the Rushton stirrer used as comparison. The Foam stirrer designs can be easily used in ordinary three-phase reactors and show a high potential for further optimization of the gas–liquid flow pattern and therefore for further increase of the rate of mass transfer.

Stavros Petrou - One of the best experts on this subject based on the ideXlab platform.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an ‘open-cell’ Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) – a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients’ DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of –3.9 points (95% confidence interval –8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an 'open-cell' Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) - a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients' DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of -3.9 points (95% confidence interval -8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 73. See the NIHR Journals Library website for further project information.

  • effect of negative pressure wound therapy vs standard wound management on 12 month disability among adults with severe open fracture of the lower limb the wollf randomized clinical trial
    JAMA, 2018
    Co-Authors: Julie Bruce, Elizabeth Tutton, Stavros Petrou, Juul Achten, Sarah E Lamb, Matthew L. Costa
    Abstract:

    Importance Open fractures of the lower limb occur when a broken bone penetrates the skin. There can be major complications from these fractures, which can be life-changing. Objectives To assess the disability, rate of deep infection, and quality of life in patients with severe open fracture of the lower limb treated with negative pressure wound therapy (NPWT) vs standard wound management after the first surgical debridement of the wound. Design, Setting, and Participants Multicenter randomized trial performed in the UK Major Trauma Network, recruiting 460 patients aged 16 years or older with a severe open fracture of the lower limb from July 2012 through December 2015. Final outcome data were collected through November 2016. Exclusions were presentation more than 72 hours after injury and inability to complete questionnaires. Interventions NPWT (n = 226) in which an open-cell Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump, creating a partial vacuum over the dressing, vs standard dressings not involving application of negative pressure (n = 234). Main Outcomes and Measures Disability Rating Index score (range, 0 [no disability] to 100 [completely disabled]) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. Secondary outcomes were complications including deep infection and quality of life (score ranged from 1 [best possible] to −0.59 [worst possible]; minimal clinically important difference, 0.08) collected at 3, 6, 9, and 12 months. Results Among 460 patients who were randomized (mean age, 45.3 years; 74% men), 88% (374/427) of available study participants completed the trial. There were no statistically significant differences in the patients’ Disability Rating Index score at 12 months (mean score, 45.5 in the NPWT group vs 42.4 in the standard dressing group; mean difference, −3.9 [95% CI, −8.9 to 1.2];P = .13), in the number of deep surgical site infections (16 [7.1%] in the NPWT group vs 19 [8.1%] in the standard dressing group; difference, 1.0% [95% CI, −4.2% to 6.3%];P = .64), or in quality of life between groups (difference in EuroQol 5-dimensions questionnaire, 0.02 [95% CI, −0.05 to 0.08]; Short Form–12 Physical Component Score, 0.5 [95% CI, −3.1 to 4.1] and Mental Health Component Score, −0.4 [95% CI, −2.2 to 1.4]). Conclusions and Relevance Among patients with severe open fracture of the lower limb, use of NPWT compared with standard wound dressing did not improve self-rated disability at 12 months. The findings do not support this treatment for severe open fractures. Trial Registration isrctn.org Identifier:ISRCTN33756652

Juul Achten - One of the best experts on this subject based on the ideXlab platform.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an ‘open-cell’ Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) – a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients’ DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of –3.9 points (95% confidence interval –8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783.

  • negative pressure wound therapy versus standard dressings for adults with an open lower limb fracture the wollf rct
    Health Technology Assessment, 2018
    Co-Authors: Sonia Davis, Susie Hennings, Keith Willett, Julie Bruce, Juul Achten, Matthew L. Costa, Stavros Petrou
    Abstract:

    Background Open fractures of the lower limb occur when a broken bone penetrates the skin and is exposed to the outside environment. These are life-changing injuries. The risk of deep infection may be as high as 27%. The type of dressing applied after surgical debridement could potentially reduce the risk of infection in the open-fracture wound. Objectives To assess the disability, rate of deep infection, quality of life and resource use in patients with severe open fracture of the lower limb treated with negative-pressure wound therapy (NPWT) versus standard wound management after the first surgical debridement of the wound. Design A pragmatic, multicentre randomised controlled trial. Setting Twenty-four specialist trauma hospitals in the UK Major Trauma Network. Participants A total of 460 patients aged ≥ 16 years with a severe open fracture of the lower limb were recruited from July 2012 through to December 2015. Patients were excluded if they presented more than 72 hours after their injury or were unable to complete questionnaires. Interventions Negative-pressure wound therapy (n = 226) where an 'open-cell' Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump which created a partial vacuum over the dressing versus standard dressings not involving negative pressure (n = 234). Main outcome measures Disability Rating Index (DRI) - a score of 0 (no disability) to 100 (completely disabled) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. The secondary outcomes were deep infection, quality of life and resource use collected at 3, 6, 9 and 12 months post randomisaton. Results There was no evidence of a difference in the patients' DRI at 12 months. The mean DRI in the NPWT group was 45.5 points [standard deviation (SD) 28.0 points] versus 42.4 points (SD 24.2 points) in the standard dressing group, giving a difference of -3.9 points (95% confidence interval -8.9 to 1.2 points) in favour of standard dressings (p = 0.132). There was no difference in HRQoL and no difference in the number of surgical site infections or other complications at any point in the 12 months after surgery. NPWT did not reduce the cost of treatment and it was associated with a low probability of cost-effectiveness. Limitations Owing to the emergency nature of the interventions, we anticipated that some patients who were randomised into the trial would subsequently be unable or unwilling to take part. Such post-randomisation withdrawal of patients could have posed a risk to the external validity of the trial. However, the great majority of these patients (85%) were found to be ineligible after randomisation. Therefore, we can be confident that the patients who took part were representative of the population with severe open fractures of the lower limb. Conclusions Contrary to the existing literature and current clinical guidelines, NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb. Future work Future work should investigate alternative strategies to reduce the incidence of infection and improve outcomes for patients with an open fracture of the lower limb. Two specific areas of potentially great benefit are (1) the use of topical antibiotic preparations in the open-fracture wound and (2) the role of orthopaedic implants with antimicrobial coatings when fixing the associated fracture. Trial registration Current Controlled Trials ISRCTN33756652 and UKCRN Portfolio ID 11783. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 73. See the NIHR Journals Library website for further project information.

  • effect of negative pressure wound therapy vs standard wound management on 12 month disability among adults with severe open fracture of the lower limb the wollf randomized clinical trial
    JAMA, 2018
    Co-Authors: Julie Bruce, Elizabeth Tutton, Stavros Petrou, Juul Achten, Sarah E Lamb, Matthew L. Costa
    Abstract:

    Importance Open fractures of the lower limb occur when a broken bone penetrates the skin. There can be major complications from these fractures, which can be life-changing. Objectives To assess the disability, rate of deep infection, and quality of life in patients with severe open fracture of the lower limb treated with negative pressure wound therapy (NPWT) vs standard wound management after the first surgical debridement of the wound. Design, Setting, and Participants Multicenter randomized trial performed in the UK Major Trauma Network, recruiting 460 patients aged 16 years or older with a severe open fracture of the lower limb from July 2012 through December 2015. Final outcome data were collected through November 2016. Exclusions were presentation more than 72 hours after injury and inability to complete questionnaires. Interventions NPWT (n = 226) in which an open-cell Solid Foam or gauze was placed over the surface of the wound and connected to a suction pump, creating a partial vacuum over the dressing, vs standard dressings not involving application of negative pressure (n = 234). Main Outcomes and Measures Disability Rating Index score (range, 0 [no disability] to 100 [completely disabled]) at 12 months was the primary outcome measure, with a minimal clinically important difference of 8 points. Secondary outcomes were complications including deep infection and quality of life (score ranged from 1 [best possible] to −0.59 [worst possible]; minimal clinically important difference, 0.08) collected at 3, 6, 9, and 12 months. Results Among 460 patients who were randomized (mean age, 45.3 years; 74% men), 88% (374/427) of available study participants completed the trial. There were no statistically significant differences in the patients’ Disability Rating Index score at 12 months (mean score, 45.5 in the NPWT group vs 42.4 in the standard dressing group; mean difference, −3.9 [95% CI, −8.9 to 1.2];P = .13), in the number of deep surgical site infections (16 [7.1%] in the NPWT group vs 19 [8.1%] in the standard dressing group; difference, 1.0% [95% CI, −4.2% to 6.3%];P = .64), or in quality of life between groups (difference in EuroQol 5-dimensions questionnaire, 0.02 [95% CI, −0.05 to 0.08]; Short Form–12 Physical Component Score, 0.5 [95% CI, −3.1 to 4.1] and Mental Health Component Score, −0.4 [95% CI, −2.2 to 1.4]). Conclusions and Relevance Among patients with severe open fracture of the lower limb, use of NPWT compared with standard wound dressing did not improve self-rated disability at 12 months. The findings do not support this treatment for severe open fractures. Trial Registration isrctn.org Identifier:ISRCTN33756652

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  • Wetting Fraction in a Tubular Reactor with Solid Foam Packing and Gas/Liquid Co-Current Downflow
    MDPI AG, 2018
    Co-Authors: Iman Mohammed, Uwe Hampel
    Abstract:

    The performance of fixed-bed reactors with structured catalysts depends heavily on the gas–liquid–Solid contacting pattern. For a broad range of flow conditions, the liquid phase does not cover the Solid surface of the packing homogeneously; this is known as partial wetting. The wetting fraction in Solid Foams was obtained using a modified electrochemical measurement method with adaption of the limiting-current technique in different pre-wetting scenarios. The external wetting fraction, which is defined as fraction of the external Solid-Foam area covered by the liquid phase to the total external Solid-Foam area, is directly linked to the overall rate of reaction through the overall liquid mass transfer rate. The wetting fraction decreased with an increase in Foam density, a process which was related to decreasing the strut thickness, increasing Foam surface area, and consequently, decreasing the wetted area. Additionally, the results indicate that a better distribution of liquid and an increased wetting fraction occurred when a spray nozzle distributor was applied. A new wetting correlation for Solid Foams is proposed to estimate the wetting fraction with consideration of Foam morphology and flow regime

  • hydrodynamics of descending gas liquid flows in Solid Foams liquid holdup multiphase pressure drop and radial dispersion
    Chemical Engineering Science, 2017
    Co-Authors: Johannes Zalucky, Markus Schubert, Uwe Hampel, Rudiger Lange, Michael Wagner
    Abstract:

    Abstract In this contribution we report on spatially resolved analysis of multiphase hydrodynamics in Solid Foam packed trickle bed reactors. For the investigation we used ultrafast X-ray computed tomography and fast response pressure transducers. The SiSiC Foams’ pore density, the liquid distribution system as well as gas and liquid flow rates were varied. The transient behavior of the liquid holdup at trickle and pulse flow as well as after drainage were examined and correlations for static and dynamic holdups were derived. The correlations are based on Eotvos, Reynolds and Galileo number, using porosity and specific area for the definition of the hydraulic diameter. The correlations are applicable to a wide range of Foam morphologies, pore densities and operating conditions reported in the literature. The axial pressure gradients in the Solid Foams showed significantly lower pressure drop compared to particle packings of similar specific surface area. The evolution of liquid spreading was analyzed qualitatively and quantitatively with various irrigation patterns. In addition, an approach for the determination of radial liquid dispersion coefficients in Solid Foams is presented.

  • pulse flow in Solid Foam packed reactors analysis of morphology and key characteristics
    Chemical Engineering Journal, 2017
    Co-Authors: Johannes Zalucky, Markus Schubert, Uwe Hampel, Rudiger Lange, Tobias Clausnitzer
    Abstract:

    Abstract In this paper, results of an experimental study on pulsing two-phase flow in SiSiC Solid Foam packed reactors are presented. Thereby, the pulse characteristics were investigated in a wide range of water and air fluxes at different axial positions for Foams with pore densities of 20, 30, and 45 ppi using the ultrafast X-ray computed tomography. Basic pulse shapes were perceived as discs, curtains and bowls, which occurred randomly. The key characteristics, i.e. frequency, velocity and volume of pulses as well as peak and time-averaged liquid holdup, have been extracted by applying a dynamic threshold criterion to time-variant liquid holdup profiles. The key properties strongly depend on axial position, pore density and fluid fluxes and can be distinguished in a local and global mode of pulsing. In the local mode, which evolves close to the regime transition boundary, pulses with small liquid volumes move slowly but frequently through the Solid Foam packed reactor. However, significantly faster pulses with large liquid volumes were encountered in the global mode. The larger pulses cover most of the reactor’s cross section but occur less frequently. Compared to literature data for conventional random packings, the pulse frequency was in a similar range, while both pulse velocity and liquid content largely exceeded their counterparts. Phenomenologically, the pore occlusion model was found to be more applicable than the concepts based on flow stability.

  • flow regime transition in open cell Solid Foam packed reactors adaption of the relative permeability concept and experimental validation
    Industrial & Engineering Chemistry Research, 2015
    Co-Authors: Johannes Zalucky, Felix Moller, Markus Schubert, Uwe Hampel
    Abstract:

    The trickle-to-pulse flow regime transition in silicon-infiltrated silicon carbide (SiSiC) Foam packed fixed bed reactors has been investigated. Based on the film stability concepts of Grosser et al. [AIChE J. 1988, 34, 1850. DOI: 10.1002/aic.690341111] as well as Attou and Ferschneider [Chem. Eng. Sci. 2000, 55, 491. DOI: 10.1016/S0009-2509(99)00344-9], two predictive models have been adapted to Foams’ specific geometric parameters. To account for the different nature of Solid Foams and their interactions with various fluids, the fixed bed characteristics (specific surface area and bed porosity) and fluid specific parameters (gas and liquid density, liquid viscosity, surface tension) have been incorporated in the model. Ergun parameters and static liquid holdup which are required for the modeling of the prevailing tractive forces were determined experimentally. The modeling results were compared to regime transition measurements performed for SiSiC Solid Foams with different linear pore densities (20, 30...

  • gas holdup of rotating Foam reactors measured by γ tomography effect of Solid Foam pore size and liquid viscosity
    Aiche Journal, 2013
    Co-Authors: R Tschentscher, Andre Bieberle, Markus Schubert, Uwe Hampel, Alexander T Nijhuis, John Van Der Schaaf, J Jaap C Schouten
    Abstract:

    Rotating Foam reactors have already shown to give high mass transfer rates compared to stirred tank reactors. For a deeper insight into the hydrodynamics of these reactors, the hydrodynamics of rotating Foam reactors were studied using -ray tomography. The two phase flow through the Foam block stirrer is mainly influenced by the Solid Foam pore size and the liquid viscosity. For low viscosity, the optimal Foam block pore size was identified in the range between 10 and 20 ppi. With smaller pore size, the gas-holdup inside the Foam block strongly increases due to bubble entrapment. For higher viscosity, pore sizes larger than 10 ppi have to be used in order to achieve a sufficient liquid flow rate through the Foam block to avoid a strong gradient over the reactor height. The effect of the hydrodynamics on the gas-liquid and liquid-Solid mass transfer and the reactor performance are discussed.