Nintedanib Therapy Alone and Combined with Mycophenolate in Patients with Systemic Sclerosis-associated Interstitial Lung Disease: Systematic Reviews and Meta-analysis

Background: The American Thoracic Society convened an international multidisciplinary panel to develop clinical practice guidelines for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Objective: To conduct a systematic review and evaluate the literature to determine whether patients with SSc-ILD should be treated with nintedanib alone or with the combination of nintedanib plus mycophenolate. Data Sources: Literature searches were conducted across MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases through June 2022 for studies using nintedanib or nintedanib plus mycophenolate to treat patients with SSc-ILD. Data Extraction: Mortality, disease progression, quality of life, and adverse event data were extracted, and meta-analysis was performed when possible. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group method was used to assess the quality of evidence. Synthesis: For nintedanib therapy alone, the systematic review included three total studies and revealed that disease progression was less in the nintedanib arm (the annual rate of decline in forced vital capacity [FVC] was 44.5 ml less, the absolute change from baseline was 46.4 ml less, and FVC% predicted was 1.2% less in the nintedanib arm) compared with placebo. However, gastrointestinal side effects and treatment discontinuation were double in the nintedanib arm compared with placebo. For combination therapy, the systematic review also included three total studies and revealed that changes in the annual rate of decline in FVC favored combination therapy over placebo (mean difference, 79.1 ml). Combination therapy was, however, associated with increased gastrointestinal adverse effects compared with placebo. The quality of evidence for all outcomes was very low as per GRADE. Conclusions: The use of nintedanib alone and in combination with mycophenolate in patients with SSc-ILD is associated with a significant reduction in disease progression compared with placebo but at the cost of increased gastrointestinal side effects and treatment discontinuation. The quality of evidence is very low.

Tocilizumab in Patients with Systemic Sclerosis-associated Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Background: The American Thoracic Society (ATS) convened an international, multidisciplinary panel to develop clinical practice guidelines for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Objective: To conduct a systematic review and evaluate the literature to determine the impact of treating patients with SSc-ILD with tocilizumab on prespecified critical and important outcomes determined by the ATS guideline panel. Data Sources: A literature search was conducted across MEDLINE, EMBASE, and Cochrane databases through June 2022 for studies using tocilizumab to treat patients with SSc-ILD. Data Extraction: Mortality and disease progression were determined to be critical outcomes of focus, with quality of life and adverse events important outcomes. Data on these outcomes were extracted and meta-analyses performed using the generic inverse variance method when possible. The Grading of Recommendations, Assessment, Development, and Evaluation Working Group method was used to assess the quality of evidence. Synthesis: The literature review resulted in five studies for inclusion. The absolute decrease from baseline in forced vital capacity (FVC) for the tocilizumab arm was 118 ml, 241 ml, and 129 ml less than the placebo arm at 24, 48, and 96 weeks, respectively, favoring tocilizumab. The mean decrease in FVC% predicted at 48 weeks was 6.50% less and the risk of decrease >10% was 66% less in the tocilizumab arm, whereas patients were 1.97 times more likely to have any increase in FVC% predicted if they received tocilizumab in place of placebo. When the placebo arm was given tocilizumab from 48 to 96 weeks, the mean change in absolute FVC was 54.90 ml less and the mean change in FVC% predicted was 1.30% less. For diffusing capacity of the lung for carbon monoxide (DlCO)% predicted, at 48 weeks there was 1.50% less change and from 48 to 96 weeks there was 5.40% less change in the tocilizumab arm. Quantitative Interstitial Lung Disease scores and Quantitative Lung Fibrosis scores at 48 weeks and modified Rodnan skin scores at 72 weeks all favored the tocilizumab arm, as did several adverse event parameters, including serious adverse events (mean difference, -27.40; 95% confidence interval, -30.10 to -24.70). The quality of evidence was very low grade. Conclusions: Tocilizumab use in patients with SSc-ILD is associated with less disease progression and a better toxicity profile than placebo. However, the quality of evidence is very low, and large prospective studies dedicated to assessing tocilizumab specifically for SSc-ILD are needed.

Rituximab in Patients with Systemic Sclerosis-associated Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Background: The American Thoracic Society convened an international, multidisciplinary panel to develop clinical practice guidelines for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Objective: To conduct a systematic review and evaluate the literature to determine whether patients with SSc-ILD should be treated with rituximab. Data Sources: A literature search was conducted across MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases through June 2022 for studies using rituximab to treat patients with SSc-ILD. Data Extraction: Disease progression, quality of life, mortality, and adverse event data were extracted. The intervention was rituximab. The standard-of-care comparator group was decided a priori by consensus of the panel as either placebo or mycophenolate. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group approach was used to assess the quality of evidence. Synthesis: Three relevant studies were selected. Rituximab significantly improved the forced vital capacity % predicted (mean difference, 3.13; 95% confidence interval [CI], 0.37 to 5.90) and the modified Rodnan Skin Score (mean difference, -7.01; 95% CI, 11.46 to -2.56) at 24-48 weeks. Conclusions: Rituximab use in patients with SSc-ILD is associated with stabilization of lung function. The quality of evidence for study outcomes was considered to be very low, as defined by the GRADE approach. Additional research on treatment with rituximab is imperative.

Treatment of Systemic Sclerosis-associated Interstitial Lung Disease: Evidence-based Recommendations. An Official American Thoracic Society Clinical Practice Guideline

Background: Interstitial lung disease (ILD) is a significant cause of morbidity and mortality in patients with systemic sclerosis (SSc). To date, clinical practice guidelines regarding treatment for patients with SSc-ILD are primarily consensus based. Methods: An international expert guideline committee composed of 24 individuals with expertise in rheumatology, SSc, pulmonology, ILD, or methodology, and with personal experience with SSc-ILD, discussed systematic reviews of the published evidence assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Predetermined conflict-of-interest management strategies were applied, and recommendations were made for or against specific treatment interventions exclusively by the nonconflicted panelists. The confidence in effect estimates, importance of outcomes studied, balance of desirable and undesirable consequences of treatment, cost, feasibility, acceptability of the intervention, and implications for health equity were all considered in making the recommendations. This was in accordance with the American Thoracic Society guideline development process, which is in compliance with the Institute of Medicine standards for trustworthy guidelines. Results: For treatment of patients with SSc-ILD, the committee: 1) recommends the use of mycophenolate; 2) recommends further research into the safety and efficacy of (a) pirfenidone and (b) the combination of pirfenidone plus mycophenolate; and 3) suggests the use of (a) cyclophosphamide, (b) rituximab, (c) tocilizumab, (d) nintedanib, and (e) the combination of nintedanib plus mycophenolate. Conclusions: The recommendations herein provide an evidence-based clinical practice guideline for the treatment of patients with SSc-ILD and are intended to serve as the basis for informed and shared decision making by clinicians and patients.

Mycophenolate in Patients with Systemic Sclerosis-associated Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Rationale: The American Thoracic Society convened an international, multidisciplinary panel to develop clinical practice guidelines for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Objective: To conduct a systematic review and evaluate the literature to determine whether patients with SSc-ILD should be treated with mycophenolate. Methods: A literature search was conducted across the MEDLINE, EMBASE, and CENTRAL databases through June 2022 for studies using mycophenolate to treat patients with SSc-ILD. Mortality, disease progression, quality of life, and adverse event data were extracted, and meta-analyses were performed when possible. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Working Group method was used to assess the quality of evidence. Results: The literature review resulted in seven studies fitting the inclusion criteria. The systematic review and meta-analyses revealed changes in forced vital capacity % predicted (mean difference [MD], 5.4%; 95% confidence interval [95% CI]: 3.3%, 7.5%), diffusing capacity of the lung for carbon monoxide % predicted (MD, 4.64%; 95% CI: 0.54%, 8.74%), and breathlessness score (MD, 1.99; 95% CI: 0.36, 3.62) favored mycophenolate over placebo. The risk of anemia (relative risk [RR], 2.3; 95% CI: 1.2, 71.4) was higher with mycophenolate. There were no significant differences between mycophenolate and cyclophosphamide, except risk of premature discontinuation (RR, 0.6; 95% CI: 0.4, 0.9), and leukopenia (RR, 0.1; 95% CI: 0.05, 0.4) favored mycophenolate. The quality of evidence was moderate to very low per GRADE. Conclusions: Mycophenolate use in patients with SSc-ILD is associated with statistically significant improvements in disease progression and quality-of-life measures compared with placebo. There were no differences in mortality, disease progression, or quality of life compared with cyclophosphamide, but there were fewer adverse events. The quality of evidence is very low.

Cyclophosphamide in Patients with Systemic Sclerosis-associated Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Background: The American Thoracic Society convened an international, multidisciplinary panel to develop clinical practice guidelines for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Objective: To conduct a systematic review and evaluate the literature to determine whether patients with SSc-ILD should be treated with cyclophosphamide. Data Sources: A literature search was conducted across the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases through June 2022 for studies using cyclophosphamide to treat patients with SSc-ILD. Data Extraction: Mortality, disease progression, quality of life, and adverse event data were extracted, and meta-analyses were performed when possible. The Grading of Recommendations, Assessment, Development and Evaluation Working Group method was used to assess the quality of evidence. Synthesis: Five studies were included; two randomized controlled trials compared cyclophosphamide versus placebo, and one randomized controlled trial and two retrospective case-control studies compared cyclophosphamide versus mycophenolate. Compared with placebo, there was a 2.83% reduction in the decline at 12 months for forced vital capacity (FVC) % predicted using cyclophosphamide (95% confidence interval [CI], 0.80-4.87; low evidence). There were improvements in breathlessness (Transition Dyspnea Index mean difference [MD], 2.90; 95% CI, 1.94-3.86; minimum clinically important difference, 1; moderate evidence) and disability (Health Assessment Questionnaire-Disability Index MD, -0.16; 95% CI, -0.28 to -0.04; minimum clinically important difference, -0.14; moderate evidence). There were increased risks of leukopenia and constitutional symptoms using cyclophosphamide, but no difference in mortality. When cyclophosphamide was compared with mycophenolate, there were differences in diffusing capacity of the lung for carbon monoxide % predicted favoring mycophenolate at 6 months (MD, -3.67%; 95% CI, -6.3% to -1.1% unadjusted; MD, -4.88%; 95% CI, -7.3% to -2.5% adjusted for alveolar volume; moderate evidence), 12 months (MD, -5.90%; 95% CI, -8.4% to -3.4% adjusted for alveolar volume; moderate evidence), and 18 months (MD, -3.26%; 95% CI, -6.1% to -0.4%; moderate evidence), but not at 24 months. There were no differences in FVC % predicted, mortality, or quality-of-life outcomes, but participants were more likely to prematurely discontinue cyclophosphamide compared with mycophenolate (relative risk, 1.70; 95% CI, 1.10-2.63; high-certainty evidence). Conclusions: A review of the published evidence shows that cyclophosphamide is effective in SSc-ILD compared with placebo, with an increased risk of side effects. However, mycophenolate may be equivocal or better than cyclophosphamide. Clinicians and patients should weigh the potential benefits and risks with respect to individual patient circumstances and preferences.

Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

Background: This American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Asociación Latinoamericana de Tórax guideline updates prior idiopathic pulmonary fibrosis (IPF) guidelines and addresses the progression of pulmonary fibrosis in patients with interstitial lung diseases (ILDs) other than IPF. Methods: A committee was composed of multidisciplinary experts in ILD, methodologists, and patient representatives. 1) Update of IPF: Radiological and histopathological criteria for IPF were updated by consensus. Questions about transbronchial lung cryobiopsy, genomic classifier testing, antacid medication, and antireflux surgery were informed by systematic reviews and answered with evidence-based recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. 2) Progressive pulmonary fibrosis (PPF): PPF was defined, and then radiological and physiological criteria for PPF were determined by consensus. Questions about pirfenidone and nintedanib were informed by systematic reviews and answered with evidence-based recommendations using the GRADE approach. Results:1) Update of IPF: A conditional recommendation was made to regard transbronchial lung cryobiopsy as an acceptable alternative to surgical lung biopsy in centers with appropriate expertise. No recommendation was made for or against genomic classifier testing. Conditional recommendations were made against antacid medication and antireflux surgery for the treatment of IPF. 2) PPF: PPF was defined as at least two of three criteria (worsening symptoms, radiological progression, and physiological progression) occurring within the past year with no alternative explanation in a patient with an ILD other than IPF. A conditional recommendation was made for nintedanib, and additional research into pirfenidone was recommended. Conclusions: The conditional recommendations in this guideline are intended to provide the basis for rational, informed decisions by clinicians.

Treatment of Nontuberculous Mycobacterial Pulmonary Disease: An Official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Home Oxygen Therapy for Adults with Chronic Lung Disease. An Official American Thoracic Society Clinical Practice Guideline

Background: Evidence-based guidelines are needed for effective delivery of home oxygen therapy to appropriate patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD).Methods: The multidisciplinary panel created six research questions using a modified Delphi approach. A systematic review of the literature was completed, and the Grading of Recommendations Assessment, Development and Evaluation approach was used to formulate clinical recommendations.Recommendations: The panel found varying quality and availability of evidence and made the following judgments: 1) strong recommendations for long-term oxygen use in patients with COPD (moderate-quality evidence) or ILD (low-quality evidence) with severe chronic resting hypoxemia, 2) a conditional recommendation against long-term oxygen use in patients with COPD with moderate chronic resting hypoxemia, 3) conditional recommendations for ambulatory oxygen use in patients with COPD (moderate-quality evidence) or ILD (low-quality evidence) with severe exertional hypoxemia, 4) a conditional recommendation for ambulatory liquid-oxygen use in patients who are mobile outside the home and require >3 L/min of continuous-flow oxygen during exertion (very-low-quality evidence), and 5) a recommendation that patients and their caregivers receive education on oxygen equipment and safety (best-practice statement).Conclusions: These guidelines provide the basis for evidence-based use of home oxygen therapy in adults with COPD or ILD but also highlight the need for additional research to guide clinical practice.

Plastic physicians: The surgical salamanders of the COVID-19 pandemic

At the time of writing, coronavirus disease-2019 (COVID-19) has affected 6.42 million people globally and over 380,000 deaths, with the United Kingdom now having the highest death rate in Europe. The plastic surgery department at Leeds Teaching Hospitals put necessary steps in place to maintain an excellent urgent elective and acute service whilst also managing COVID-positive medical patients in the ward. We describe the structures and pathways implemented together with complex decision-making, which has allowed us to respond early and effectively. We hope these lessons will prove a useful tool as we look to open conversations around the recovery of normal activity.

Treatment of Nontuberculous Mycobacterial Pulmonary Disease: An Official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America

Asymptomatic bacteriuria (ASB) is a common finding in many populations, including healthy women and persons with underlying urologic abnormalities. The 2005 guideline from the Infectious Diseases Society of America recommended that ASB should be screened for and treated only in pregnant women or in an individual prior to undergoing invasive urologic procedures. Treatment was not recommended for healthy women; older women or men; or persons with diabetes, indwelling catheters, or spinal cord injury. The guideline did not address children and some adult populations, including patients with neutropenia, solid organ transplants, and nonurologic surgery. In the years since the publication of the guideline, further information relevant to ASB has become available. In addition, antimicrobial treatment of ASB has been recognized as an important contributor to inappropriate antimicrobial use, which promotes emergence of antimicrobial resistance. The current guideline updates the recommendations of the 2005 guideline, includes new recommendations for populations not previously addressed, and, where relevant, addresses the interpretation of nonlocalizing clinical symptoms in populations with a high prevalence of ASB.

Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America

Asymptomatic bacteriuria (ASB) is a common finding in many populations, including healthy women and persons with underlying urologic abnormalities. The 2005 guideline from the Infectious Diseases Society of America recommended that ASB should be screened for and treated only in pregnant women or in an individual prior to undergoing invasive urologic procedures. Treatment was not recommended for healthy women; older women or men; or persons with diabetes, indwelling catheters, or spinal cord injury. The guideline did not address children and some adult populations, including patients with neutropenia, solid organ transplants, and nonurologic surgery. In the years since the publication of the guideline, further information relevant to ASB has become available. In addition, antimicrobial treatment of ASB has been recognized as an important contributor to inappropriate antimicrobial use, which promotes emergence of antimicrobial resistance. The current guideline updates the recommendations of the 2005 guideline, includes new recommendations for populations not previously addressed, and, where relevant, addresses the interpretation of nonlocalizing clinical symptoms in populations with a high prevalence of ASB.

Treatment of nontuberculous mycobacterial pulmonary disease: an official ATS/ERS/ESCMID/IDSA clinical practice guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

2018 Infectious Diseases Society of America Clinical Practice Guideline for the Management of Outpatient Parenteral Antimicrobial Therapy

A panel of experts was convened by the Infectious Diseases Society of America (IDSA) to update the 2004 clinical practice guideline on outpatient parenteral antimicrobial therapy (OPAT) [1]. This guideline is intended to provide insight for healthcare professionals who prescribe and oversee the provision of OPAT. It considers various patient features, infusion catheter issues, monitoring questions, and antimicrobial stewardship concerns. It does not offer recommendations on the treatment of specific infections. The reader is referred to disease- or organism-specific guidelines for such support.

2018 Infectious Diseases Society of America Clinical Practice Guideline for the Management of Outpatient Parenteral Antimicrobial Therapy

A panel of experts was convened by the Infectious Diseases Society of America to update the 2004 clinical practice guideline on outpatient parenteral antimicrobial therapy (OPAT) [1]. This guideline is intended to provide insight for healthcare professionals who prescribe and oversee the provision of OPAT. It considers various patient features, infusion catheter issues, monitoring questions, and antimicrobial stewardship concerns. It does not offer recommendations on the treatment of specific infections. The reader is referred to disease- or organism-specific guidelines for such support.

Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

BACKGROUND

This document provides clinical recommendations for the diagnosis of idiopathic pulmonary fibrosis (IPF). It represents a collaborative effort between the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society.

METHODS

The evidence syntheses were discussed and recommendations formulated by a multidisciplinary committee of IPF experts. The evidence was appraised and recommendations were formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

The guideline panel updated the diagnostic criteria for IPF. Previously defined patterns of usual interstitial pneumonia (UIP) were refined to patterns of UIP, probable UIP, indeterminate, and alternate diagnosis. For patients with newly detected interstitial lung disease (ILD) who have a high-resolution computed tomography scan pattern of probable UIP, indeterminate, or an alternative diagnosis, conditional recommendations were made for performing BAL and surgical lung biopsy; because of lack of evidence, no recommendation was made for or against performing transbronchial lung biopsy or lung cryobiopsy. In contrast, for patients with newly detected ILD who have a high-resolution computed tomography scan pattern of UIP, strong recommendations were made against performing surgical lung biopsy, transbronchial lung biopsy, and lung cryobiopsy, and a conditional recommendation was made against performing BAL. Additional recommendations included a conditional recommendation for multidisciplinary discussion and a strong recommendation against measurement of serum biomarkers for the sole purpose of distinguishing IPF from other ILDs.

CONCLUSIONS

The guideline panel provided recommendations related to the diagnosis of IPF.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Executive Summary: Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.These guidelines are intended for use by healthcare professionals who care for patients at risk for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), including specialists in infectious diseases, pulmonary diseases, critical care, and surgeons, anesthesiologists, hospitalists, and any clinicians and healthcare providers caring for hospitalized patients with nosocomial pneumonia. The panel's recommendations for the diagnosis and treatment of HAP and VAP are based upon evidence derived from topic-specific systematic literature reviews.

An Official American Thoracic Society Research Statement: Impact of Mild Obstructive Sleep Apnea in Adults

BACKGROUND

Mild obstructive sleep apnea (OSA) is a highly prevalent disorder in adults; however, whether mild OSA has significant neurocognitive and cardiovascular complications is uncertain.

OBJECTIVES

The specific goals of this Research Statement are to appraise the evidence regarding whether long-term adverse neurocognitive and cardiovascular outcomes are attributable to mild OSA in adults, evaluate whether or not treatment of mild OSA is effective at preventing or reducing these adverse neurocognitive and cardiovascular outcomes, delineate the key research gaps, and provide direction for future research agendas.

METHODS

Literature searches from multiple reference databases were performed using medical subject headings and text words for OSA in adults as well as by hand searches. Pragmatic systematic reviews of the relevant body of evidence were performed.

RESULTS

Studies were incongruent in their definitions of "mild" OSA. Data were inconsistent regarding the relationship between mild OSA and daytime sleepiness. However, treatment of mild OSA may improve sleepiness in patients who are sleepy at baseline and improve quality of life. There is limited or inconsistent evidence pertaining to the impact of therapy of mild OSA on neurocognition, mood, vehicle accidents, cardiovascular events, stroke, and arrhythmias.

CONCLUSIONS

There is evidence that treatment of mild OSA in individuals who demonstrate subjective sleepiness may be beneficial. Treatment may also improve quality of life. Future research agendas should focus on clarifying the effect of mild OSA and impact of effective treatment on other neurocognitive and cardiovascular endpoints as detailed in the document.

Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.These guidelines are intended for use by healthcare professionals who care for patients at risk for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), including specialists in infectious diseases, pulmonary diseases, critical care, and surgeons, anesthesiologists, hospitalists, and any clinicians and healthcare providers caring for hospitalized patients with nosocomial pneumonia. The panel's recommendations for the diagnosis and treatment of HAP and VAP are based upon evidence derived from topic-specific systematic literature reviews.

The Diagnosis and Management of Alpha-1 Antitrypsin Deficiency in the Adult

Background: The diagnosis and clinical management of adults with alpha-1 antitrypsin deficiency (AATD) have been the subject of ongoing debate, ever since the publication of the first American Thoracic Society guideline statement in 1989.¹ In 2003, the "American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1 Antitrypsin Deficiency" made a series of evidence-based recommendations, including a strong recommendation for broad-based diagnostic testing of all symptomatic adults with chronic obstructive pulmonary disease (COPD).² Even so, AATD remains widely under-recognized. To update the 2003 systematic review and clinical guidance, the Alpha-1 Foundation sponsored a committee of experts to examine all relevant, recent literature in order to provide concise recommendations for the diagnosis and management of individuals with AATD. Purpose: To provide recommendations for: (1) the performance and interpretation of diagnostic testing for AATD, and (2) the current management of adults with AATD and its associated medical conditions. Methods: A systematic review addressing the most pressing questions asked by clinicians (clinician-centric) was performed to identify citations related to AATD that were published since the 2003 comprehensive review, specifically evaluating publications between January 2002 and December 2014. Important, more recent publications were solicited from the writing committee members as well. The combined comprehensive literature reviews of the 2003 document and this current review comprise the evidence upon which the committee's conclusions and recommendations are based. Results: Recommendations for the diagnosis and management of AATD were formulated by the committee. Conclusions: The major recommendations continue to endorse and reinforce the importance of testing for AATD in all adults with symptomatic fixed airflow obstruction, whether clinically labeled as COPD or asthma. Individuals with unexplained bronchiectasis or liver disease also should be tested. Family testing of first-degree relatives is currently the most efficient detection technique. In general, individuals with AATD and emphysema, bronchiectasis, and/or liver disease should be managed according to usual guidelines for these clinical conditions. In countries where intravenous augmentation therapy with purified pooled human plasma-derived alpha-1 antitrypsin is available, recent evidence now provides strong support for its use in appropriate individuals with lung disease due to AATD.

Long term study into surgical re-exploration of the 'free flap in difficulty'

BACKGROUND

Free tissue transfers must survive in order to achieve their surgical goals. There is little consensus about managing the 'failing' free flap, and practice is often guided by anecdote.

MATERIAL AND METHODS

We have prospectively collected data about all free flaps performed within our department between 1985 and 2008 (2569 flaps). We identified 327 flaps which were re-explored a total of 369 times. We analysed these flaps with regard to indication for re-exploration, operative findings and outcome.

RESULTS

Thirteen percent (327) of free flaps were re-explored. Of these, 291 (83%) had a successful outcome. Successful re-explorations took place at a mean 19h post-op and unsuccessful re-explorations at a mean 56h post-op. Clinical diagnosis prior to re-exploration was confirmed operatively in 91% of cases.

CONCLUSION

We have considered the factors that allowed us to achieve the salvage rates described over a prolonged period, and identified two key areas. Firstly, we favour a model for free flap monitoring with clinical judgement at its core. Secondly, we feel the facility to recover patients post-operatively in a specialised, warmed environment, and return them to theatre quickly should the need arise, is essential. These two simple, yet institutionally determined factors are vital for maintaining excellent success rates.

["Flowsecure" artificial urinary sphincter: a new adjustable artificial urinary sphincter concept with conditional occlusion for stress urinary incontinence]

INTRODUCTION

To spread de concept of a new artificial urinary sphincter with conditional occlusion for stress incontinence. The new prototype was conceived and designed in The Institute of Urology and Nephrology of London by Professor Craggs M. and Professor Mundy A.R.

METHODS

The FlowSecure sphincter consists of an adjustable pressure-regulating balloon, a stress relief reservoir, a control pump and valve assembly unit with self-sealing port and a urethral cuff. The pressure regulating balloon determinates de operating pressure of the device; the pressure is adjustable in the range 0-80 cm H2O and can be altered by injection or removal of normal saline through the self sealing port. The stress relief balloon transmits transient intrabdominal pressure to the cuff during periods of stress. An adjustable circular urethral cuff minimises creasing and possible stress fractures.

RESULTS

The device is implanted as a one-piece assembly which is pre-filled with sterile saline. The surgical technique is simple and associated with little handling, reducing risk of infection and potential assembly errors. The adjustable pressure regulating balloon in association with the stress relief reservoir enables the cuff occluding pressure to be set at a low range, therefore reducing the risk for atrophy and erosion.

DISCUSSION

The new FlowSecure urinary artificial sphincter with conditional occlusion is designed to provide good continence rates adjusting regulating pressures when needed and conceived to reduce the risk of potential complications associated with excessive occluding pressures and mechanical failures.

Assessing the influence of field- and GIS-based inquiry on student attitude and conceptual knowledge in an undergraduate ecology lab

Combining field experience with use of information technology has the potential to create a problem-based learning environment that engages learners in authentic scientific inquiry. This study, conducted over a 2-yr period, determined differences in attitudes and conceptual knowledge between students in a field lab and students with combined field and geographic information systems (GIS) experience. All students used radio-telemetry equipment to locate fox squirrels, while one group of students was provided an additional data set in a GIS to visualize and quantify squirrel locations. Pre/postsurveys and tests revealed that attitudes improved in year 1 for both groups of students, but differences were minimal between groups. Attitudes generally declined in year 2 due to a change in the authenticity of the field experience; however, attitudes for students that used GIS declined less than those with field experience only. Conceptual knowledge also increased for both groups in both years. The field-based nature of this lab likely had a greater influence on student attitude and conceptual knowledge than did the use of GIS. Although significant differences were limited, GIS did not negatively impact student attitude or conceptual knowledge but potentially provided other benefits to learners.

Three-dimensional MRI of the male urethrae with implanted artificial sphincters: initial results

The aim of this study was to develop a method for simultaneous 3D visualization of a new type of artificial urethral sphincter (AUS) and adjacent urinary structures. Serial MR tomograms were acquired from seven men after AUS implantation. 3D reconstruction was performed by thresholding original (positive) and inverted (negative) image intensity and by subsequently fusing positive and negative images. Results show that the bladder, cuff and balloons of the AUS of originally high intensity were imaged in 3D by thresholding the positive datasets. The urethrae and corpora cavernosa penis of originally low intensity were displayed in 3D by thresholding the negative datasets. Fusion of the positive and negative datasets allowed simultaneous visualization of the AUS complex and adjacent urinary structures. All the structures of interest were also clearly seen by interactive multiplanar reformatting. Coronal tomographic datasets provided better 3D and reformatted 2D images than sagittal and transverse datasets. This technique offers a simple means for evaluating the complex urethral anatomy and the AUS, and has potential for improved 3D visualization of many other complex morphological and pathological conditions.

A simple and fail safe method for digital tourniquet

Digital tourniquets are commonly used to provide a bloodless field for surgery to the finger. Such tourniquets, however, are potentially harmful and disastrous consequences occur if they are accidentally left in place. We propose a modification of the rubber glove tourniquet technique that will provide a safe and reliable tourniquet.

Neuromodulation through sacral nerve roots 2 to 4 with a Finetech-Brindley sacral posterior and anterior root stimulator

STUDY DESIGN

Investigation of five patients receiving an implant, using laboratory cystometry and self-catheterisation at home.

OBJECTIVES

To use the established Finetech-Brindley sacral root stimulator to increase bladder capacity by neuromodulation, eliminating the need for posterior rhizotomy, as well as achieving bladder emptying by neurostimulation.

SETTING

Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.

METHODS

Five patients underwent implantation of a Finetech-Brindley stimulator without rhizotomy of the posterior roots. This was either a two channel extradural device (four cases) or a three channel intrathecal device (one case). In each patient, the implant was configured as a Sacral Posterior and Anterior Root Stimulator (SPARS). Postoperatively, repeated provocations using rapid instillation of 60 ml saline were used to determine the relative thresholds for neuromodulation using each channel. The effect of continuous neuromodulation was examined in the laboratory using slow fill cystometrograms, and conditional stimulation was also studied (neuromodulation for 1 min to suppress hyperreflexic contractions as they occurred). In one patient, neuromodulation was applied continuously at home, and volumes at self catheterisation recorded in a diary.

RESULTS

Reflex erections were preserved in each patient. In three patients, detrusor hyperreflexia persisted postoperatively and neuromodulation via the implant was studied. In these three patients, the configuration was: S2 mixed roots bilaterally (channel B), and S34 bilaterally (channel A). Both channels could be used to suppress provoked hyperreflexic contractions, with the S2 channel effective at a shorter pulse width than S34 in a majority of cases. Continuous stimulation more than doubled bladder capacity in two out of three patients during slow fill cystometry. Conditional stimulation was highly effective. In the one patient who used continuous stimulation at home, bladder capacity was more than doubled and the effect was comparable with anticholinergic medication. Bladder pressures >70 cm water could be achieved with intense stimulation in three patients, but detrusor-external urethral sphincter dyssynergia (DSD) prevented complete emptying.

CONCLUSIONS

Neuromodulation via a SPARS was effective and may replace the need for posterior rhizotomy. However, persisting DSD may prevent complete bladder emptying and warrants further investigation.

The acute effects of continuous and conditional neuromodulation on the bladder in spinal cord injury

STUDY DESIGN

Laboratory investigation using serial slow-fill cystometrograms.

OBJECTIVES

To examine the acute effects of different modes of dorsal penile nerve stimulation on detrusor hyperreflexia, bladder capacity and bladder compliance in spinal cord injury (SCI).

SETTING

Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.

METHODS

Fourteen SCI patients were examined. Microtip transducer catheters enabled continuous measurement of anal sphincter, urethral sphincter and intravesical pressures. Control cystometrograms were followed by stimulation of the dorsal penile nerve at 15 Hz, 200 micros pulse width and amplitude equal to twice that which produced a pudendo-anal reflex. Stimulation was either continuous or in bursts of one minute triggered by a rise in detrusor pressure of 10 cm water (conditional). Further control cystometrograms were then performed to examine the residual effects of stimulation.

RESULTS

Bladder capacity increased significantly during three initial control fills. Continuous stimulation (n=6) significantly increased bladder capacity by a mean of 110% (+/-Standard Deviation 85%) or 173 ml (+/-146 ml), and bladder compliance by a mean of 53% (+/-31%). Conditional stimulation in a different group of patients (n=6) significantly increased bladder capacity, by 144% (+/-127%) or 230 ml (+/-143 ml). In the conditional neuromodulation experiments, the gap between suppressed contractions fell reliably as bladder volume increased, and the time from start of stimulation to peak of intravesical pressure and 50% decline in intravesical pressure rise was 2.8 s (+/-0.9 s) and 7.6 s (+/-1.0s) respectively. The two methods of stimulation were compared in six patients; in four out of six conditional neuromodulation resulted in a higher mean bladder capacity than continuous, but the difference was not significant.

CONCLUSIONS

Both conditional and continuous stimulation significantly increase bladder capacity. The conditional mode is probably at least as effective as the continuous, suggesting that it could be used in an implanted device for bladder suppression.

Establishing predictive indicators for the status of loaded soft tissues

Two complementary techniques were employed to assess the soft tissue response to applied pressure. The noninvasive methods involve the simultaneous measurement of the local tensions of oxygen and carbon dioxide (tcPo 2 and tcPco 2) and the collection and subsequent analysis of sweat collected from the sacrum, a common site for the development of pressure sores. All tests were performed on able-bodied subjects. Results have indicated that oxygen levels (tcPo 2) were lowered in soft tissues subjected to applied pressures of between 40 (5.3 kPa) and 120 mmHg (16.0 kPa). At the higher pressures, this decrease was generally associated with an increase in carbon dioxide levels (tcPco 2) well above the normal basal levels of 45 mmHg (6 kPa). There were also considerable increases, in some cases up to twofold, in the concentrations of both sweat lactate and urea at the loaded site compared with the unloaded control. By comparing selected parameters, a threshold value for loaded tcPo 2 was identified, representing a reduction of ∼60% from unloaded values. Above this threshold, there was a significant relationship between this parameter and the loaded/unloaded concentration ratios for both sweat metabolites. These parameters may prove useful in identifying those subjects whose soft tissue may be compromised during periods of pressure ischemia.

Fix and flap: the radical orthopaedic and plastic treatment of severe open fractures of the tibia

We performed a retrospective review of the case notes of 84 consecutive patients who had suffered a severe (Gustilo IIIb or IIIc) open fracture of the tibia after blunt trauma between 1990 and 1998. All had been treated by a radical protocol which included early soft-tissue cover with a muscle flap by a combined orthopaedic and plastic surgery service. Our ideal management is a radical debridement of the wound outside the zone of injury, skeletal stabilisation and early soft-tissue cover with a vascularised muscle flap. All patients were followed clinically and radiologically to union or for one year. After exclusion of four patients (one unrelated death and three patients lost to follow-up), we reviewed 80 patients with 84 fractures. There were 67 men and 13 women with a mean age of 37 years (3 to 89). Five injuries were grade IIIc and 79 grade IIIb; 12 were site 41, 43 were site 42 and 29 were site 43. Debridement and stabilisation of the fracture were invariably performed immediately. In 33 cases the soft-tissue reconstruction was also completed in a single stage, while in a further 30 it was achieved within 72 hours. In the remaining 21 there was a delay beyond 72 hours, often for critical reasons unrelated to the limb injury. All grade-IIIc injuries underwent immediate vascular reconstruction, with an immediate cover by a flap in two. All were salvaged. There were four amputations, one early, one mid-term and two late, giving a final rate of limb salvage of 95%. Overall, nine pedicled and 75 free muscle flaps were used; the rate of flap failure was 3.5%. Stabilisation of the fracture was achieved with 19 external and 65 internal fixation devices (nails or plates). Three patients had significant segmental defects and required bone-transport procedures to achieve bony union. Of the rest, 51 fractures (66%) progressed to primary bony union while 26 (34%) required a bone-stimulating procedure to achieve this outcome. Overall, there was a rate of superficial infection of the skin graft of 6%, of deep infection at the site of the fracture of 9.5%, and of serious pin-track infection of 37% in the external fixator group. At final review all patients were walking freely on united fractures with no evidence of infection. The treatment of these very severe injuries by an aggressive combined orthopaedic and plastic surgical approach provides good results; immediate internal fixation and healthy soft-tissue cover with a muscle flap is safe. Indeed, delay in cover (>72 hours) was associated with most of the problems. External fixation was associated with practical difficulties for the plastic surgeons, a number of chronic pin-track infections and our only cases of malunion. We prefer to use internal fixation. We recommend primary referral to a specialist centre whenever possible. If local factors prevent this we suggest that after discussion with the relevant centre, initial debridement and bridging external fixation, followed by transfer, is the safest procedure.

The fissura antitragohelicina: an anatomic aid to the correction of prominent ears

One of the important features of correction of prominent ears involves the creation of an antihelical fold in the ear cartilage. The precise and symmetrical location of this fold is crucial for the aesthetic result. This study investigated the use of the fissura antitragohelicina, a constant anatomic landmark, as a guide to the correct line for the new antihelix. In the first part of the study, 16 cadaveric ears were dissected. The fissura antitragohelicina was present in each specimen, and measurements of the distance between the fissura antitragohelicina and the helix and the antihelix were recorded. Based on this study, a clinical series of 20 consecutive prominent ear corrections were performed using the fissura antitragohelicina as a guide for the creation of a new, symmetrical antihelical fold. The aesthetic results were satisfactory by subjective assessment in every one of this group of patients. This study showed that the fissura antitragohelicina was a constant, reliable, and simple guide to the creation of the antihelical fold in patients with prominent ears.

Malignant schwannoma in a burn scar

The malignant potential of a burn scar is well recognized. Epidermal malignancies predominate and sarcomas are a rare finding. The first case of a malignant schwannoma developing in a burn scar is reported, and the management discussed.

Fungal growth within a silicone tissue expander: case report

Fungal contamination of tissue expanders has not previously been reported. There are, however, reports of fungi in association with inflatable breast prostheses. Colonisation of a tissue expander with Aspergillus niger resulting in mechanical obstruction of the device is described. The possible modes of inoculation and survival of the organism within the expander envelope were studied including an investigation of the permeability to gases of the silicone expander envelope. Recommendations are made about prevention of this complication.

Double V-Y advancement flaps in the reconstruction of skin defects of the anterior lower limb

A double V-Y advancement flap based upon a vertical subcutaneous pedicle was assessed for reconstruction of moderate sized defects of the anterior lower leg. The technique is described and the results of a retrospective analysis of thirteen cases are given. The procedure has proven to be a reliable alternative means of providing skin cover in this area.

Neonatal cleft lip repair in Ayrshire; a contribution to the debate

Neonatal cleft lip repair has been the normal practice in Ayrshire, Scotland, for the last 10 years. The surgical results are briefly presented. Anaesthetic and paediatric considerations are discussed. Assuming careful preoperative assessment is made, the procedure carries minimal morbidity, can give good results and is believed to offer distinct advantages to the parents and child.

Effects of incandescent radiation on photosynthesis, growth rate and yield of 'Waldmann's Green' leaf lettuce

Effects of different ratios incandescent (ln) to fluorescent (Fl) radiation were tested on growth of 'Waldmann's Green' leaf lettuce (Lactuca sativa L.) in a controlled environment. After 4 days of treatment, dry weight, leaf area, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and photosynthetic rate (Pn) were greater for plants grown at 84 rather than 16% of total irradiance (82 W m-2) from ln lamps. Although leaf dry weight and area were 12-17% greater at 84% ln after the first 8 days of treatment, there were no differences in RGR or Pn between treatments during the last 4 days. If 84% ln was compared with 50% ln, all cumulative growth parameters, RGR, NAR and Pn were greater for 84% ln during the first 4 days of treatment. However, during the second 4 days, RGR was greater for the 50% ln treatment, resulting in no net difference in leaf dry weight or area between treatments. Shifting from 84 to 50% ln radiation between the first and second 4 days of treatment increased plant dry weight, leaf area, RGR and NAR relative to those under 84% ln for 8 days continuously.

Effects of CO2 and photosynthetic photon flux on yield, gas exchange and growth rate of Lactuca sativa L. 'Waldmann's Green.'

Enrichment of CO2 to 46 mmol m-3 (1000 mm3 dm-3) at a moderate photosynthetic photon flux (PPF) of 450 micromoles m-2 s-1 stimulated fresh and dry weight gain of lettuce leaves 39% to 75% relative to plants at 16 mmol m-3 CO2 (350 mm3 dm-3). Relative growth rate (RGR) was stimulated only during the first several days of exponential growth. Elevating CO2 above 46 mmol m-3 at moderate PPF had no further benefit. However, high PPF of 880-900 micromoles m-2 s-1 gave further, substantial increases in growth, RGR, net assimilation rate (NAR) and photosynthetic rate (Pn), but a decrease in leaf area ratio (LAR), at 46 or 69 mmol m-3 (1000 or 1500 mm3 dm-3) CO2, the differences being greater at the higher CO2 level. Enrichment of CO2 to a supraoptimal level of 92 mmol m-3 (2000 mm3 dm-3) at high PPF increased leaf area and LAR, decreased specific leaf weight, NAR and Pn and had no effect on leaf, stem and root dry weight or RGR relative to plants grown at 69 mmol m-3 CO2 after 8 d of treatment. The results of the study indicate that leaf lettuce growth is most responsive to a combination of high PPF and CO2 enrichment to 69 mmol m-3 for several days at the onset of exponential growth, after which optimizing resources might be conserved.

Minitron II system for precise control of the plant growth environment

A transparent, cylindrical chamber system was developed to allow measurement of gas-exchange by small crop canopies in the undisturbed plant growth environment. The system is an elaboration of the Minitron system developed previously to compare growth of small plants in different environments within the same general growth area. The Minitron II system described herein accommodates hydroponic culture and separate control of atmospheric composition in individual chambers. Root and shoot environments are compartmented separately to accommodate atmospheres of different flow rate and/or gaseous composition. A series of 0-rings and tension-adjustable springs allow carbon dioxide in the flowing atmosphere to be analyzed without cross-contamination between chamber compartments or from external gas sources. Carbon dioxide has been maintained at set point +/- 9 g m-3 over a range of CO2 concentrations from 382 to 2725 g m-3 and with an atmosphere turnover rate of 136.7 cm3 s-1 by computer-assisted mass flow controllers. Each chamber has dimensions large enough (61 cm internal diameter, 0.151 m3 internal volume) to allow adequate replication of individual plants for statistical purposes (e.g., up to 36 equally-spaced plant holders). No significant variation in growth or photosynthetic rate of leaf lettuce occurred between chambers for a given set of environmental conditions. Gas-exchange rates in different chambers changed to a similar extent as CO2 concentration in the flowing atmosphere or chamber temperature were varied by the same amount. When coupled with appropriate control systems, Minitron II chambers can provide separate controlled environments for multiple small plants with adequate precision and at relatively low cost.

Growth and yield characteristics of 'Waldmann's Green' leaf lettuce under different photon fluxes from metal halide or incandescent + fluorescent radiation

'Waldmann's Green' leaf lettuce (Lactuca sativa L.) was grown either under 84% irradiance from incandescent (In) + 16% from fluorescence (Fl) lamps, or 100% from metal halide (MH) lamps, both at 392 micromoles s-1 m-2 of photosynthetically active radiation (400-700 nm) from 11 to 19 days after seeding. No differences in leaf dry weight, leaf area, relative growth rate (RGR) or photosynthesis (Pn) occurred after 8 days of exposure to these radiation treatments for 20 h day-1. However, a 23% reduction in root dry weight, a 123% increase in stem length and a 61% increase in stem dry weight were found with In + Fl relative to MH radiation. A photosynthetic photon flux (PPF) of 920 micromoles s-1 m-2 from the In + Fl source increased leaf dry weight by 13% and RGR by 21% relative to those at 460 micromoles s-1 m-2 from the same source. From 4 to 8 days of treatment, high PPF did not lower shoot dry gain, but did lower RGR. Photosynthesis and net assimilation rate were lower while leaf area ratio was higher at 460 than at 920 micromoles s-1 m-2 over the 8-day treatment period. When PPF from MH lamps was 400 micromoles s-1 m-2, leaf dry weight was 20% greater than if PPF was 805 micromoles s-1 m-2 after 4 days of treatment, but no differences were detected after 8 days. Relative growth rate increased by 11% during the first 4 days, but declined by 12% during the second 4 days under high- relative to low-PPF MH radiation. Lettuce productivity was stimulated by high PPF from either lamp type from Day 11 to Day 14, but not from Day 15 to Day 19 after seeding.

Stimulating productivity of hydroponic lettuce in controlled environments with triacontanol

Triacontanol (1-triacontanol) applied as a foliar spray at 10(-7) M to 4-day-old, hydroponically grown leaf lettuce (Lactuca sativa L.) seedlings in a controlled environment increased leaf fresh and dry weight 13% to 20% and root fresh and dry weight 13% to 24% 6 days after application, relative to plants sprayed with water. When applied at 8 as well as 4 days after seeding, triacontanol increased plant fresh and dry weight, leaf area, and mean relative growth rate 12% to 37%. There was no benefit of repeating application of triacontanol in terms of leaf dry weight gain.