Dead-Space Ventilation Indices and Mortality in Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

OBJECTIVES

Acute respiratory distress syndrome (ARDS) is associated with high ventilation-perfusion heterogeneity and dead-space ventilation. However, whether the degree of dead-space ventilation is associated with outcomes is uncertain. In this systematic review and meta-analysis, we evaluated the ability of dead-space ventilation measures to predict mortality in patients with ARDS.

DATA SOURCES

MEDLINE, CENTRAL, and Google Scholar from inception to November 2022.

STUDY SELECTION

Studies including adults with ARDS reporting a dead-space ventilation index and mortality.

DATA EXTRACTION

Two reviewers independently identified eligible studies and extracted data. We calculated pooled effect estimates using a random effects model for both adjusted and unadjusted results. The quality and strength of evidence were assessed using the Quality in Prognostic Studies and Grading of Recommendations, Assessment, Development, and Evaluation, respectively.

DATA SYNTHESIS

We included 28 studies in our review, 21 of which were included in our meta-analysis. All studies had a low risk of bias. A high pulmonary dead-space fraction was associated with increased mortality (odds ratio [OR], 3.52; 95% CI, 2.22-5.58; p < 0.001; I2 = 84%). After adjusting for other confounding variables, every 0.05 increase in pulmonary-dead space fraction was associated with an increased odds of death (OR, 1.23; 95% CI, 1.13-1.34; p < 0.001; I2 = 57%). A high ventilatory ratio was also associated with increased mortality (OR, 1.55; 95% CI, 1.33-1.80; p < 0.001; I2 = 48%). This association was independent of common confounding variables (OR, 1.33; 95% CI, 1.12-1.58; p = 0.001; I2 = 66%).

CONCLUSIONS

Dead-space ventilation indices were independently associated with mortality in adults with ARDS. These indices could be incorporated into clinical trials and used to identify patients who could benefit from early institution of adjunctive therapies. The cut-offs identified in this study should be prospectively validated.

Ventilatory efficiency measured during sub-maximal cardiopulmonary exercise testing predicts postoperative outcomes following heart transplantation

Cardiopulmonary exercise testing is commonly used to evaluate patients for heart transplantation. We assessed the utility of ventilatory efficiency (VE/VCO₂ ) to predict perioperative outcomes following heart transplantation. We retrospectively reviewed all patients undergoing cardiopulmonary exercise testing prior to heart transplantation at our center. Spearman's coefficient showed a correlation between VE/VCO₂ and ICU free days in the first 30-days post-transplant (R = -.37, p < .01). A V_E /VCO₂ cut-off >35 was associated with significantly lower median ICU-free days (23.0 vs. 27 days; p < .01) and a higher likelihood of postoperative morbidity (OR = 5.64, 95% CI = 1.75-18.16; p < .01). Multiple regression analysis controlling for peak oxygen consumption and right heart catheter parameters showed VE/VCO₂ >35 is independently associated with lower ICU-free days (p < .01) and postoperative morbidity (p = .02). Peak oxygen consumption <15 mL/min/kg was not associated with higher ICU or hospital-free days. VE/VCO₂ >35 independently predicts early postoperative morbidity in patients undergoing heart transplantation.

Exercise induced bronchodilation: a phenomenon more common, greater magnitude and more prolonged in older adults than in adolescents

Objective. There are few studies in clinically healthy subjects describing and quantifying exercise-induced bronchodilation (EIB_d). This study aimed to describe and compare the magnitude and time course changes in post-exercise forced expired volume at the first second (FEV₁) in healthy adolescents, younger adults, and older adults.Methods. Adolescent (n = 73, aged 10-17 yrs), younger adult (n = 35, aged 18-25 yrs) and older adult (n = 25, aged 35-66 yrs) subjects with normal spirometry z-scores completed a maximal cardiopulmonary exercise test using the standardised exponential exercise test protocol on a cycle ergometer performed at stable temperature and humidity. Spirometry was performed pre-exercise and at 1-, 3-, 5-, and 10- minutes post-exercise to determine the percentage change in FEV₁ compared to baseline. EIB_d was defined as a ≥5% increase in post-exercise FEV₁.Results. Increases in FEV₁ at one-minute post-exercise were observed in the adolescents (1.3%) and young adults (6.0%) with FEV₁ returning to baseline after ten minutes. Compared to the adolescents, the older adults showed significantly greater and sustained increases in FEV₁ at 1-, 3-, 5-, and 10- minutes post-exercise (6.4, 4.6, 4.7, and 3.8%, p < 0.05). At 1-minute post exercise a significantly greater proportion of younger adults (54%, p < 0.01) and older adults (64%, p < 0.01) demonstrated EIB_d compared to the adolescent group (15%).Conclusion. Healthy older adults had a higher prevalence, greater magnitude and more prolonged EIB_d compared to healthy adolescent and young adult subjects.

Cardiorespiratory responses to muscle metaboreflex activation in fibrosing interstitial lung disease

New Findings

What is the central question of this study?

We determined whether sensory feedback from metabolically sensitive skeletal muscle afferents (metaboreflex) causes a greater ventilatory response and higher dyspnoea ratings in fibrosing interstitial lung disease (FILD).

What is the main finding and its importance?

Ventilatory responses and dyspnoea ratings during handgrip exercise and metaboreflex isolation were not different in FILD and control groups. Blood pressure and heart rate responses to handgrip were attenuated in FILD but not different to controls during metaboreflex isolation. These findings suggest that the muscle metaboreflex contribution to the respiratory response to exercise is not altered in FILD.

Abstract

Exercise limitation and dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD); however, the physiological mechanisms are poorly understood. In other respiratory diseases, there is evidence that an augmented muscle metaboreflex may be implicated. We hypothesized that metaboreflex activation in FILD would result in elevated ventilation and dyspnoea ratings compared to healthy controls, due to augmented muscle metaboreflex. Sixteen FILD patients (three women, 69±14 years; mean±SD) and 16 age‐matched controls (four women, 67±7 years) were recruited. In a randomized cross‐over design, participants completed two min of rhythmic handgrip followed by either (i) two min of post‐exercise circulatory occlusion (PECO trial) to isolate muscle metaboreflex activation, or (ii) rested for four min (Control trial). Minute ventilation (V˙E; pneumotachometer), dyspnoea ratings (0–10 Borg scale), mean arterial pressure (MAP; finger photoplethysmography) and heart rate (HR; electrocardiogram) were measured. V˙E was higher in the FILD group at baseline and exercise increased V˙E similarly in both groups. V˙E remained elevated during PECO, but there was no between‐group difference in the magnitude of this response (ΔV˙E FILD 4.2 ± 2.5 L·min^–1 vs. controls 3.6 ± 2.4 L·min^–1, P = 0.596). At the end of PECO, dyspnoea ratings in FILD were similar to controls (1.0 ± 1.3 units vs. 0.5 ± 1.1 units). Exercise increased MAP and HR (P < 0.05) in both groups; however, responses were lower in FILD. Collectively, these findings suggest that there is not an augmented effect of the muscle metaboreflex on breathing and dyspnoea in FILD, but haemodynamic responses to handgrip are reduced relative to controls.

Quantifying tidal expiratory flow limitation using a vector-based analysis technique

Objective. Tidal expiratory flow limitation (EFL_T) is commonly identified by tidal breaths exceeding the forced vital capacity (FVC) loop. This technique, known as the Hyatt method, is limited by the difficulties in defining the FVC and tidal flow-volume (TV) loops. The vector-based analysis (VBA) technique described and piloted in this manuscript identifies and quantifies EFL_Tas tidal breaths that conform to the contour of the FVC loop.Approach. The FVC and TV loops are interpolated to generate uniformly spaced plots. VBA is performed to determine the smallest vector difference between each point on the FVC and TV curves, termed the flow reserve vector (FRV). From the FVC point yielding the lowest FRV, the tangential angles of the FVC and TV segments are recorded. If the TV and FVC loops become parallel, the difference between the tangential angles tends towards zero. We infer EFL_Tas parallel TV and FVC segments where the FRV is < 0.1 and the tangential angle is within ±18 degrees for ≥5% of TV. EFL_Tis quantified by the percent of TV loop fulfilling these criteria. We compared the presence and degree of EFL_Tat rest and during peak exercise using the Hyatt method and our VBA technique in 25 healthy subjects and 20 subjects with moderate-severe airflow obstruction.Main results. Compared to the Hyatt method, our VBA technique reported a significantly lower degree of EFL_Tin healthy subjects during peak exercise, and in obstructed subjects at rest and during peak exercise. In contrast to the Hyatt method, our VBA technique re-classified five subjects (one in the healthy group and four in the obstructed group) as demonstrating EFL_T.Significance.Our VBA technique provides an alternative approach to determine and quantify EFL_Twhich may reduce the overestimation of the degree EFL_Tand more accurately identify subjects experiencing EFL_T.

Aspects of the modern management of bronchiectasis

While bronchiectasis is an old condition, it is only in the last decade that there have been major strides in our understanding of the condition and its treatment. Recent evidence has shown that the "vicious cycle hypothesis" remains valid. This and the concept of "treatable traits" provide useful frameworks on which to base the management of this condition. In all patients recently diagnosed, a search should be undertaken for specific etiologies. A number of factors including chronic infection by Pseudomonas aerigunosa, have been shown to be associated with increased morbidity and mortality. While airway clearance strategies remain the mainstay of therapy, other treatments including nebulized hypertonic saline and inhaled antibiotic treatment are discussed. There is greater emphasis being placed on immune-modulatory therapies, not just long term macrolide therapy but other more innovative strategies. The role of surgical lung resection in the management of this condition is also discussed.

Surgical treatment of non-small-cell lung cancer in octogenarians: a single-centre retrospective study

Lung resection in patients aged ≥80 years is considered high risk and contributes to the low rates of resection in this population. This review of 79 octogenarians who underwent curative surgery for non-small-cell lung cancer demonstrated no intraoperative mortality, 30-day mortality of 1.3% and 12-month mortality of 10%. In this selected cohort of octogenarians, surgery resulted in acceptable short- to medium-term outcomes.

Novel application of Poincaré analysis to detect and quantify exercise oscillatory ventilation

Objective.Exercise oscillatory ventilation (EOV) is frequently observed in individuals with cardiac disease. Assessment of EOV relies on pattern recognition and this subjectivity and lack of quantification limits the widespread clinical use of EOV as a prognostic marker. Poincaré analysis quantifies the short (SD1) and long-term (SD2) variability of a signal and may provide an alternative means to identify and quantify unstable exercise breathing patterns. This study aimed to determine if Poincaré analysis can distinguish between the breathing patterns of healthy control subjects and individuals being assessed for heart transplantation with and without EOV.Approach.Thirty-nine subjects performed a cardiopulmonary exercise test as part of heart transplant assessment and were subjectively classified into two groups according to the presence of EOV: non-EOV (n = 19) and EOV (n = 20). The control group (n = 24) consisted of healthy adults. Poincaré analysis (SD1 and SD2) was performed for minute ventilation (V̇_E) and tidal volume (VT) normalized to forced vital capacity (V̇_EnandV̇_Tn), and breathing frequency (BF) for breath-by-breath data over the 10-15 ml · min^-1 · kg^-1V̇_O2range.Main results.Poincaré analysis showed similar exercise ventilatory responses between the non-EOV and control group. BF was found to discriminate between subjects with stable and unstable ventilation. BF SD1 was significantly higher in the EOV group compared to the non-EOV (7.9 versus 4.6,p < 0.01) and control (7.9 versus 4.2,p < 0.01) groups. The EOV group had significantly greater BF SD2 compared to the non-EOV (5.7 versus 3.5,p < 0.01) and control (5.7 versus 3.5,p < 0.01) groups.Significance.We demonstrated that this novel application of Poincaré analysis can objectively distinguish and quantify unstable from stable breathing patterns during exercise. In subjects being assessed for heart transplantation the presence of EOV is associated with greater BF variability. Poincaré analysis provides an objective measure to identify and quantify EOV.Summary at a glance.As EOV may indicate abnormal ventilatory control, there is a need for an objective measure to identify and quantify unstable from stable ventilation during exercise. We developed a method of quantifying BF variation by the application of Poincaré analysis and demonstrated higher than normal variability of BF in subjects being assessed for heart transplantation who demonstrated EOV.

Development of an RNAi therapeutic for alpha-1-antitrypsin liver disease

The autosomal codominant genetic disorder alpha-1 antitrypsin (AAT) deficiency (AATD) causes pulmonary and liver disease. Individuals homozygous for the mutant Z allele accumulate polymers of Z-AAT protein in hepatocytes, where AAT is primarily produced. This accumulation causes endoplasmic reticulum (ER) stress, oxidative stress, damage to mitochondria, and inflammation, leading to fibrosis, cirrhosis, and hepatocellular carcinoma. The magnitude of AAT reduction and duration of response from first-generation intravenously administered RNA interference (RNAi) therapeutic ARC-AAT and then with next-generation subcutaneously administered ARO-AAT were assessed by measuring AAT protein in serum of the PiZ transgenic mouse model and human volunteers. The impact of Z-AAT reduction by RNAi on liver disease phenotypes was evaluated in PiZ mice by measuring polymeric Z-AAT in the liver; expression of genes associated with fibrosis, autophagy, apoptosis, and redox regulation; inflammation; Z-AAT globule parameters; and tumor formation. Ultrastructure of the ER, mitochondria, and autophagosomes in hepatocytes was evaluated by electron microscopy. In mice, sustained RNAi treatment reduced hepatic Z-AAT polymer, restored ER and mitochondrial health, normalized expression of disease-associated genes, reduced inflammation, and prevented tumor formation. RNAi therapy holds promise for the treatment of patients with AATD-associated liver disease. ARO-AAT is currently in phase II/III clinical trials.

Risk of breast cancer in patients with lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare metastasizing pulmonary disease that shares some clinical, cellular, and molecular similarities with metastatic breast cancer to lung. LAM cells have been identified circulating in various body fluids of patients and, intriguingly, diverse evidence indicates that these cells may originate from a different organ to the lung. Following on from these observations, we hypothesized the existence of a common risk basis between LAM and breast cancer, and suggested increased risk of breast cancer among LAM patients. Here, by studying two additional LAM cohorts with more detailed epidemiological, life-style, and disease-related data, we show consistent results; a potential excess of estrogen-receptor-positive young breast cancer cases in LAM. This observation further suggests the need of prospective studies to precisely assess the association between both diseases.

Inhaled corticosteroids for bronchiectasis

BACKGROUND

Bronchiectasis is being increasingly diagnosed and recognised as an important contributor to chronic lung disease in both adults and children in high- and low-income countries. It is characterised by irreversible dilatation of airways and is generally associated with airway inflammation and chronic bacterial infection. Medical management largely aims to reduce morbidity by controlling the symptoms, reduce exacerbation frequency, improve quality of life and prevent the progression of bronchiectasis. This is an update of a review first published in 2000.

OBJECTIVES

To evaluate the efficacy and safety of inhaled corticosteroids (ICS) in children and adults with stable state bronchiectasis, specifically to assess whether the use of ICS: (1) reduces the severity and frequency of acute respiratory exacerbations; or (2) affects long-term pulmonary function decline.

SEARCH METHODS

We searched the Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Register of trials, MEDLINE and Embase databases. We ran the latest literature search in June 2017.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing ICS with a placebo or no medication. We included children and adults with clinical or radiographic evidence of bronchiectasis, but excluded people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

We reviewed search results against predetermined criteria for inclusion. In this update, two independent review authors assessed methodological quality and risk of bias in trials using established criteria and extracted data using standard pro forma. We analysed treatment as 'treatment received' and performed sensitivity analyses.

MAIN RESULTS

The review included seven studies, involving 380 adults. Of the 380 randomised participants, 348 completed the studies.Due to differences in outcomes reported among the seven studies, we could only perform limited meta-analysis for both the short-term ICS use (6 months or less) and the longer-term ICS use (> 6 months).During stable state in the short-term group (ICS for 6 months or less), based on the two studies from which data could be included, there were no significant differences from baseline values in the forced expiratory volume in the first second (FEV₁) at the end of the study (mean difference (MD) -0.09, 95% confidence interval (CI) -0.26 to 0.09) and forced vital capacity (FVC) (MD 0.01 L, 95% CI -0.16 to 0.17) in adults on ICS (compared to no ICS). Similarly, we did not find any significant difference in the average exacerbation frequency (MD 0.09, 95% CI -0.61 to 0.79) or health-related quality of life (HRQoL) total scores in adults on ICS when compared with no ICS, though data available were limited. Based on a single non-placebo controlled study from which we could not extract clinical data, there was marginal, though statistically significant improvement in sputum volume and dyspnoea scores on ICS.The single study on long-term outcomes (over 6 months) that examined lung function and other clinical outcomes, showed no significant effect of ICS on any of the outcomes. We could not draw any conclusion on adverse effects due to limited available data.Despite the authors of all seven studies stating they were double-blind, we judged one study (in the short duration ICS) as having a high risk of bias based on blinding, attrition and reporting of outcomes. The GRADE quality of evidence was low for all outcomes (due to non-placebo controlled trial, indirectness and imprecision with small numbers of participants and studies).

AUTHORS' CONCLUSIONS

This updated review indicates that there is insufficient evidence to support the routine use of ICS in adults with stable state bronchiectasis. Further, we cannot draw any conclusion for the use of ICS in adults during an acute exacerbation or in children (for any state), as there were no studies.

A randomized evaluation of the acute efficacy, acceptability and tolerability of Flutter and active cycle of breathing with and without postural drainage in non-cystic fibrosis bronchiectasis

Airway clearance is integral to the management of bronchiectasis, yet there is no evidence as to the optimal modality. The aim of this randomized prospective study was to evaluate the acute efficacy, acceptability and tolerability of three airway clearance techniques in non-cystic fibrosis (non-CF) bronchiectasis. Flutter, active cycle of breathing technique (ACBT) and ACBT with postural drainage (ACBT-PD) were evaluated in random order over a week in 36 patients (mean age 62 years, range 33-83), with stable non-CF bronchiectasis. Total sputum wet weight for ACBT-PD was twice that of either ACBT alone or Flutter. No objective difference in treatment duration was noted. All three techniques were well accepted and tolerated. Patient preference was 16 (44%) for Flutter, eight (22%) ACBT and 12 (33%) for ACBT-PD. Patient demography, factors such as upper airways or reflux symptoms, previous use or acute efficacy did not predict preference. This is the first randomized systematic evaluation of acute efficacy, acceptability and tolerability of Flutter, ACBT and ACBT-PD in non-CF bronchiectasis. All three techniques were well tolerated but ACBT-PD proved superior in terms of acute efficacy. Patient preference for treatment modality could not be predicted.

An international, multicentre evaluation and description of Burkholderia pseudomallei infection in cystic fibrosis

BACKGROUND

Several cases of Burkholderia pseudomallei infection in CF have been previously reported. We aimed to identify all cases globally, risk factors for acquisition, clinical consequences, and optimal treatment strategies.

METHODS

We performed a literature search to identify all published cases of B. pseudomallei infection in CF. In addition we hand-searched respiratory journals, and contacted experts in infectious diseases and CF around the world. Supervising clinicians for identified cases were contacted and contemporaneous clinical data was requested.

RESULTS

25 culture-confirmed cases were identified. The median age at acquisition was 21 years, mean FEV1 % predicted was 60 %, and mean BMI was 19.5 kg/m(2). The location of acquisition was northern Australia or south-east Asia for most. 19 patients (76 %) developed chronic infection, which was usually associated with clinical decline. Successful eradication strategies included a minimum of two weeks of intravenous ceftazidime, followed by a consolidation phase with trimethoprim/sulfamethoxazole, and this resulted in a higher chance of success when instituted early. Three cases of lung transplantation have been recorded in the setting of chronic B. pseudomallei infection.

CONCLUSION

Chronic carriage of B. pseudomallei in patients with CF appears common after infection, in contrast to the non-CF population. This is often associated with an accelerated clinical decline. Lung transplantation has been performed in select cases of chronic B. pseudomallei infection.

Optimising inhaled mannitol for cystic fibrosis in an adult population

Abstract

There has been remarkable progress in the treatment of cystic fibrosis (CF) patients over the past 20 years. However, limitations of standard therapies have highlighted the need for a convenient alternative treatment to effectively target the pathophysiologic basis of CF-related disease by improving mucociliary clearance of airway secretions and consequently improve lung function and reduce respiratory exacerbations. Mannitol is an osmotic agent available as a dry powder, dispensed in a convenient disposable inhaler device for the treatment of adult patients with CF. Inhalation of mannitol as a dry powder is thought to change the viscoelastic properties of airway secretions, increase the hydration of the airway surface liquid and contribute to increased mucociliary and cough clearance of retained secretions. In two large phase 3 studies [1, 2], long-term use of inhaled mannitol resulted in a significant and clinically meaningful improvement in lung function relative to control in adult CF subjects and had an acceptable safety profile. Clinical experience with inhaled mannitol confirms that it is safe and effective. A minority of patients are unable to tolerate the medication. However, through training in proper inhaler technique and setting clear expectations regarding therapeutic effects, both the tolerance and adherence necessary for long term efficacy can be positively influenced.

Educational aims

Key points

Closure of a broncho-pleural fistula using an atrial septal defect occluder

Broncho-pleural fistulae (BPF) are recognised as a rare complication following pneumonectomy. We describe a patient, who after failing conservative treatment, underwent closure of a persistent fistula with an atrial septal defect (ASD) occluder. Additionally we review the literature regarding management of BPF and the emerging role of cardiac defect closure devices as a possible treatment option.

Phase 3 randomized study of the efficacy and safety of inhaled dry powder mannitol for the symptomatic treatment of non-cystic fibrosis bronchiectasis

BACKGROUND

Inhaled dry powder mannitol enhanced mucus clearance and improved quality of life over 2 weeks in non-cystic fibrosis bronchiectasis. This study's objective was to investigate the efficacy and safety of dry powder mannitol over 12 weeks.

METHODS

Patients with bronchiectasis confirmed by high-resolution CT (HRCT) scan, aged 15 to 80 years, with FEV1≥50% predicted and ≥1 L participated in a randomized, placebo-controlled, double-blind study. Patients with a negative mannitol provocation test were randomized to inhale 320 mg mannitol (n=231) or placebo (n=112) bid for 12 weeks. To further assess safety, the same mannitol dose/frequency was administered to a patient subset in an open-label extension over 52 weeks. Primary end points were changes from baseline at 12 weeks in 24-h sputum weight and St. George's Respiratory Questionnaire (SGRQ) score.

RESULTS

There was a significant difference of 4.3 g in terms of change in sputum weight over 12 weeks (95% CI, 1.64-7.00; P=.002) between mannitol and placebo; however, this was largely driven by a decrease in sputum weight in the placebo group. This was associated, in turn, with more antibiotic use in the placebo group (50 of 112 [45%]) than in the inhaled mannitol group (85 of 231 [37%]). There was no statistical difference between the groups (P=.304) in total SGRQ score (mannitol, -3.4 points [95% CI, -4.81 to -1.94] vs placebo, -2.1 points [95% CI, -4.12 to -0.09]). In a subgroup study (n=82), patients receiving mannitol showed less small airway mucus plugging on HRCT scan at 12 weeks compared with patients receiving placebo (P=.048). Compliance rates were high, and mannitol was well tolerated with adverse events similar to those of placebo.

CONCLUSION

Because the difference in sputum weights appears to be associated with increased antibiotic use in the placebo group, a larger controlled study is now required to investigate the long-term mannitol effect on pulmonary exacerbations and antibiotic use.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT0027753; URL: www.clinicaltrials.gov.

Chronic obstructive pulmonary disease in non-smokers: a case-comparison study

BACKGROUND

COPD is often regarded as a smoker's disease. In fact, up to 50% of COPD could be attributable to other causes. Relatively little is known about COPD among nonsmokers, and this group is usually excluded from studies of COPD.

METHODS

In this cross-sectional case-comparison study, smokers and nonsmokers aged over 45 with COPD (post-bronchodilator FEV1 ≤ 70% predicted, FEV1/FVC ratio < 0.7) were recruited from specialist outpatient clinics and from primary care. Subjects completed a questionnaire and interview, and underwent spirometry, venesection, exhaled nitric oxide (ENO) measurement, allergen skinprick testing, formal lung function testing and high resolution CT.

RESULTS

48 nonsmokers and 45 smokers participated. Asthma was nearly universal among nonsmokers and was the commonest identifiable cause of COPD in that group. Nonsmokers also exhibited a high prevalence of objective eosinophilic inflammation (raised ENO and eosinophil counts, positive skinprick tests). Smokers had more severe airflow obstruction, but respiratory symptom prevalences were similar between groups. Nonsmokers reported greater lifetime burdens of respiratory disease. Nonsmokers' HRCT results showed functional small airways disease, with no significant emphysema in any subject. Previously undiagnosed bronchiectasis was common in both groups (31% and 42%).

CONCLUSIONS

Asthma is a very common cause of COPD among nonsmokers. Radiological bronchiectasis is common in COPD; the clinical significance of this finding is unclear.

Inhaled, dual release liposomal ciprofloxacin in non-cystic fibrosis bronchiectasis (ORBIT-2): a randomised, double-blind, placebo-controlled trial

Background

The delivery of antipseudomonal antibiotics by inhalation to Pseudomonas aeruginosa-infected subjects with non-cystic fibrosis (CF) bronchiectasis is a logical extension of treatment strategies successfully developed in CF bronchiectasis. Dual release ciprofloxacin for inhalation (DRCFI) contains liposomal ciprofloxacin, formulated to optimise airway antibiotic delivery.

Methods

Phase II, 24-week Australian/New Zealand multicentre, randomised, double-blind, placebo-controlled trial in 42 adult bronchiectasis subjects with ≥2 pulmonary exacerbations in the prior 12 months and ciprofloxacin-sensitive P aeruginosa at screening. Subjects received DRCFI or placebo in three treatment cycles of 28 days on/28 days off. The primary outcome was change in sputum P aeruginosa bacterial density to the end of treatment cycle 1 (day 28), analysed by modified intention to treat (mITT). Key secondary outcomes included safety and time to first pulmonary exacerbation—after reaching the pulmonary exacerbation endpoint subjects discontinued study drug although remained in the study.

Results

DRCFI resulted in a mean (SD) 4.2 (3.7) log₁₀ CFU/g reduction in P aeruginosa bacterial density at day 28 (vs −0.08 (3.8) with placebo, p=0.002). DRCFI treatment delayed time to first pulmonary exacerbation (median 134 vs 58 days, p=0.057 mITT, p=0.046 per protocol). DRCFI was well tolerated with a similar incidence of systemic adverse events to the placebo group, but fewer pulmonary adverse events.

Conclusions

Once-daily inhaled DRCFI demonstrated potent antipseudomonal microbiological efficacy in adults with non-CF bronchiectasis and ciprofloxacin-sensitive P aeruginosa. In this modest-sized phase II study, DRCFI was also well tolerated and delayed time to first pulmonary exacerbation in the per protocol population.

Fixed airflow obstruction among nonsmokers with asthma:a case-comparison study

BACKGROUND

Airflow obstruction in asthma is usually reversible, but fixed obstruction develops in some individuals. Little is known about risk factors for development of fixed airflow obstruction in nonsmokers with asthma.

METHODS

This case-comparison study recruited nonsmokers aged over 45 years with physician-diagnosed asthma from specialist outpatient clinics and primary care. Two age-matched groups were recruited on the basis of spirometry: anobstructed group (post-bronchodilator FEV(1) ≤ 70% predicted, FEV1/FVC ratio < lower limit of normal) and a control group with normal lung function. Subjects completed a questionnaire and interview, and underwent spirometry, venesection, exhaled nitric oxide (ENO) measurement, allergen skinprick testing, and formal lung function testing.

RESULTS

Thirty-four obstructed subjects and 40 controls participated in the study. Obstructed subjects exhibited greater evidence of systemic inflammation, abnormal glucose homeostasis, and central obesity than controls. Obstructed subjects reported longer duration of asthma, and childhood respiratory infection was commoner in that group. Metabolic syndrome prevalence was similar between groups, but several features of insulin resistance were associated with reduced FEV(1). Cough and sputum were common among controls.

CONCLUSIONS

Risk of fixed airflow obstruction may correlate with lifetime asthma duration. Individuals with coexisting asthma and fixed airflow obstruction have heightened systemic inflammation. A variety of chronic respiratory symptoms are common among "healthy" nonsmokers with asthma.

VEGFR-2, CXCR-2 and PAR-1 germline polymorphisms as predictors of survival in pancreatic carcinoma

BACKGROUND

Hypoxic environment of pancreatic cancer (PC) implicates high vascular in-growth, which may be influenced by angiogenesis-related germline polymorphisms. Our purpose was to evaluate polymorphisms of vascular endothelial growth factor receptor 2 (VEGFR-2), CXC chemokine receptor 2 (CXCR-2), proteinase-activated receptor 1 (PAR-1) and endostatin (ES) as prognostic markers for disease-free (DFS) and overall survival (OS) in PC.

PATIENTS AND METHODS

Genotyping of 173 patients, surgically treated for PC between 2004 and 2011, was carried out by TaqMan(®) genotyping assays or polymerase chain reaction. Chi-square test, Kaplan-Meier estimator and Cox regression hazard model were used to assess the prognostic value of selected polymorphisms.

RESULTS

VEGFR-2 -906 T/T and PAR-1 -506 Del/Del genotypes predicted longer DFS (P = 0.003, P = 0.014) and OS (VEGFR-2 -906, P = 0.011). CXCR-2 +1208 T/T genotype was a negative predictor for DFS (P < 0.0001). Combined analysis for DFS and OS indicated that patients with the fewest number of favorable genotypes simultaneously present (VEGFR-2 -906 T/T, CXCR-2 +1208 C/T or C/C and PAR-1 -506 Del/Del) were at the highest risk for recurrence or death (P < 0.0001).

CONCLUSION

VEGFR-2 -906 C>T, CXCR-2 +1208 C>T and PAR-1 -506 Ins/Del polymorphisms are potential predictors for survival in PC.

Pooled analysis of two large randomised phase III inhaled mannitol studies in cystic fibrosis

BACKGROUND

To evaluate safety and efficacy of inhaled mannitol treatment in subgroups of a large global CF population.

METHODS

Data were pooled from two multicentre, double-blind, randomised, controlled, parallel group phase III studies in which 600 patients inhaled either mannitol (400 mg) or control (mannitol 50 mg) twice a day for 26 weeks.

RESULTS

Both the mean absolute change in FEV(1) (mL) and relative change in FEV(1) by % predicted from baseline for mannitol (400 mg) versus control were statistically significant (73.42 mL, 3.56%, both p<0.001). Increases in FEV(1) were observed irrespective of rhDNase use. Significant improvements in FEV1 occurred in adults but not children (6-11) or adolescents (aged 12-17). Pulmonary exacerbation incidence was reduced by 29% (p=0.039) in the mannitol (400 mg) group.

CONCLUSIONS

Sustained six-month improvements in lung function and decreased pulmonary exacerbation incidence indicate that inhaled mannitol is an important additional drug in the treatment of CF.

Influence of mediterranean diet on asthma symptoms, lung function, and systemic inflammation: a randomized controlled trial

OBJECTIVE

The rapidly increasing prevalence of asthma in developed countries suggests an environmental cause. The benefits of Mediterranean diet (MD) in cardiovascular disease have been tentatively attributed to its anti-inflammatory properties. Asthma is an inflammatory disease and MD is associated with reduced asthma risk in epidemiological studies, but there are no reported interventional studies of MD in asthma.

METHODS

In this 12-week open-label randomized trial, 38 adults with symptomatic asthma were allocated to high-intervention (HI), low-intervention (LI), and control groups. The first two groups were encouraged to adopt an MD and received multiple consultation sessions with a nutritionist, written advice, and vouchers for the purchase of appropriate foods. Food frequency questionnaires, asthma control questionnaires, asthma-related quality of life questionnaires (AQLQs), and spirometry were completed at the beginning and at the end of the study.

RESULTS

The MDt score increased in the HI group (p < .001), indicating successful alteration of dietary behavior. Statistically, nonsignificant improvements were seen in spirometry and several AQLQ subdomains in the two intervention groups. No changes were seen in the asthma control or in inflammatory markers.

CONCLUSIONS

The trial intervention has successfully altered the dietary behavior among adults with asthma. Small but consistent improvements were seen in quality of life and spirometry among the intervention group. The use of the MD to treat asthma is feasible and warrants evaluation in a larger study, powered to examine clinical endpoints.

The prevalence and predictors of airway hyperresponsiveness in sarcoidosis

BACKGROUND AND OBJECTIVE

Obstructive airflow limitation is the most common physiological impairment in sarcoidosis. This study determined the prevalence of airway hyperresponsiveness (AHR) in sarcoidosis, the correlation between responses to direct (using histamine) and indirect (using hypertonic saline) bronchial challenge, and the clinical, physiological and radiological predictors of AHR.

METHODS

Subjects with sarcoidosis and a baseline forced expiratory volume in 1 s (FEV(1)) >35% predicted underwent hypertonic and histamine challenge, lung function testing and high resolution computed tomography (HRCT) of the chest. AHR was defined as a 15% fall in FEV(1) to hypertonic saline and a 20% fall in FEV(1) to histamine.

RESULTS

The 52 subjects had well-preserved lung function (FEV(1) = 2.8 ± 0.7 L, 87% predicted). AHR was detected in 5/47 (11%) to hypertonic saline and 19/43 (44%) to histamine challenge. On univariate analysis, response to histamine challenge was predicted by conglomerate fibrosis (P = 0.02) and reticular pattern (P = 0.03) on HRCT. The baseline % predicted forced expiratory volume in 1 s was significantly inversely associated with AHR on univariate (P = 0.004) and multivariate analysis (P = 0.01) when adjusted by HRCT patterns.

CONCLUSIONS

The higher prevalence of AHR using histamine challenge than hypertonic saline challenge and the association with baseline % predicted FEV(1) suggest that the AHR in sarcoidosis may reflect the consequences of airway remodelling following inflammation.

Health equity in the New Zealand health care system: a national survey

Introduction

In all countries people experience different social circumstances that result in avoidable differences in health. In New Zealand, Māori, Pacific peoples, and those with lower socioeconomic status experience higher levels of chronic illness, which is the leading cause of mortality, morbidity and inequitable health outcomes. Whilst the health system can enable a fairer distribution of good health, limited national data is available to measure health equity. Therefore, we sought to find out whether health services in New Zealand were equitable by measuring the level of development of components of chronic care management systems across district health boards. Variation in provision by geography, condition or ethnicity can be interpreted as inequitable.

Methods

A national survey of district health boards (DHBs) was undertaken on macro approaches to chronic condition management with detail on cardiovascular disease, chronic obstructive pulmonary disease, congestive heart failure, stroke and diabetes. Additional data from expert informant interviews on program reach and the cultural needs of Māori and Pacific peoples was sought. Survey data were analyzed on dimensions of health equity relevant to strategic planning and program delivery. Results are presented as descriptive statistics and free text. Interviews were transcribed and NVivo 8 software supported a general inductive approach to identify common themes.

Results

Survey responses were received from the majority of DHBs (15/21), some PHOs (21/84) and 31 expert informants. Measuring, monitoring and targeting equity is not systematically undertaken. The Health Equity Assessment Tool is used in strategic planning but not in decisions about implementing or monitoring disease programs. Variable implementation of evidence-based practices in disease management and multiple funding streams made program implementation difficult. Equity for Māori is embedded in policy, this is not so for other ethnic groups or by geography. Populations that conventional practitioners find hard to reach, despite recognized needs, are often underserved. Nurses and community health workers carried a disproportionate burden of care. Cultural and diversity training is not a condition of employment.

Conclusions

There is a struggle to put equity principles into practice, indicating will without enactment. Equity is not addressed systematically below strategic levels and equity does not shape funding decisions, program development, implementation and monitoring. Equity is not incentivized although examples of exceptional practice, driven by individuals, are evident across New Zealand.

National variability in provision of health services for major long-term conditions in New Zealand (a report from the ABCC NZ study)

INTRODUCTION

Chronic illness is the leading cause of morbidity, mortality, and inequitable health outcomes in New Zealand. The ABCCNZ Stocktake aimed to identify extent of long-term conditions management evidence-based practices in stroke, cardiovascular disease, chronic obstructive pulmonary disease and congestive heart failure in New Zealand's District Health Boards (DHBs).

METHODS

Eleven 'dimensions' of care for long-term conditions, identified by literature review and confirmed at workshops with long-term conditions professionals, formed the basis of the Stocktake of all 21 DHBs. It comprised two questionnaires: a generic component capturing perceptions of practice; and a disease-specific component assessing service provision.

RESULTS

Fifteen DHBs completed all or parts of the questionnaires. Data accrual was completed in July 2008. Although most DHBs had developed long-term conditions management strategies to a moderate degree, there was considerable variability of practice between DHBs. DHBs thought their PHOs had developed strategies in some areas to a low to moderate level, though cardiovascular disease provision rated more highly. Regarding disease-specific services, larger DHBs had greater long-term conditions management provision not only of tertiary services, but of standard care, leadership, self-management, case-management, and audit.

CONCLUSIONS

There is considerable variability in perceptions of long-term conditions management service provision across DHBs. In many instances variability in actual disease-specific service provision appears to relate to DHB size.

Chronic suppurative lung disease and bronchiectasis in children and adults in Australia and New Zealand

Consensus recommendations for managing chronic suppurative lung disease (CSLD) and bronchiectasis, based on systematic reviews, were developed for Australian and New Zealand children and adults during a multidisciplinary workshop. The diagnosis of bronchiectasis requires a high-resolution computed tomography scan of the chest. People with symptoms of bronchiectasis, but non-diagnostic scans, have CSLD, which may progress to radiological bronchiectasis. CSLD/bronchiectasis is suspected when chronic wet cough persists beyond 8 weeks. Initial assessment requires specialist expertise. Specialist referral is also required for children who have either two or more episodes of chronic (> 4 weeks) wet cough per year that respond to antibiotics, or chest radiographic abnormalities persisting for at least 6 weeks after appropriate therapy. Intensive treatment seeks to improve symptom control, reduce frequency of acute pulmonary exacerbations, preserve lung function, and maintain a good quality of life. Antibiotic selection for acute infective episodes is based on results of lower airway culture, local antibiotic susceptibility patterns, clinical severity and patient tolerance. Patients whose condition does not respond promptly or adequately to oral antibiotics are hospitalised for more intensive treatments, including intravenous antibiotics. Ongoing treatment requires regular and coordinated primary health care and specialist review, including monitoring for complications and comorbidities. Chest physiotherapy and regular exercise should be encouraged, nutrition optimised, environmental pollutants (including tobacco smoke) avoided, and vaccines administered according to national immunisation schedules. Individualised long-term use of oral or nebulised antibiotics, corticosteroids, bronchodilators and mucoactive agents may provide a benefit, but are not recommended routinely.

Complimentary roles for N-terminal pro-B-type natriuretic peptide and spirometry to assess functional capacity in patients with complex mixed heart valve disease

BACKGROUND

Assessing the effects of valvular heart disease on functional capacity is important for optimal timing of surgery.

AIM

To determine whether N-terminal pro-B type natriuretic peptide (NT-proBNP) and lung spirometry predict maximum oxygen consumption (pVO(2)) on cardio-pulmonary exercise testing in patients with mixed heart valve disease.

METHODS

Forty-five clinically stable patients with moderate-severe stenosis and/or regurgitation of the aortic, mitral and/or tricuspid valves were studied. The ability of echocardiography, NT-proBNP, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) to predict impaired pVO(2) was determined.

RESULTS

On univariate analysis the natural logarithm of NT-proBNP explained more of the variation in pVO(2) (r(2) = 0.40, p < 0.0001) than valve severity score (r(2) = 0.20, p = 0.002), pulmonary artery pressure (r(2) = 0.21, p = 0.005), left atrial area index (r(2) = 0.25, p = 0.001) or LV ejection fraction (r(2) = 0.02, p = 0.4). Low lean body weight (r(2) = 0.21, p = 0.002), FEV1 (r(2) = 0.26, p = 0.0003) and FVC (r(2) = 0.20, p = 0.002) were also associated with pVO(2). In multi-variable analysis independent determinants of pVO(2) were NT-proBNP (r(2) = 0.27, p = 0.001), FVC (r(2) = 0.20, p = 0.0002) and lean body weight (r(2) = 0.23, p = 0.001). NT-proBNP and FVC together were better predictors of pVO(2) < 60% (C statistic = 0.83, 95% CI 0.71, 0.95) than either NT-proBNP (C = 0.80, 95% CI 0.66, 0.94) or FVC (C =0.73, 95% CI 0.57, 0.89) alone. NT-proBNP, FVC and age also predicted excessive ventilation on cardio-pulmonary exercise (combined r(2) = 0.54, p < 0.0001).

CONCLUSION

In patients with mixed heart valve disease NT-proBNP and spirometry provide a more reliable assessment of functional capacity than assessment by echocardiography and symptoms alone.

Radiotherapy utilisation in lung cancer in New Zealand: disparities with optimal rates explained

BACKGROUND AND PURPOSE

The intervention rate (IR) of radiotherapy (RT) is important for health service planning. As actual IRs are commonly lower than those predicted by models, we sought to determine the reasons for this discrepancy, using lung cancer in a mixed urban-rural region of New Zealand (NZ).

METHODS

The appropriate utilisation of RT was calculated as the sum of the actual utilisation 3 years post diagnosis (88% of cases deceased), the estimated utilisation of the 12% remaining alive, and the percentage of cases that may have benefited from RT but did not receive it.

RESULTS

The actual utilisation was estimated as 43% (range 40-48%). A further 8% of deceased cases may have benefitted from RT (but were not referred), giving an appropriate utilisation of 51%. An additional 3.5% that may have benefitted from RT declined management. The difference from modelled IRs was due to a combination of early mortality, refusal of treatment and assumed higher RT treatment rates for many clinical scenarios.

CONCLUSION

The appropriate utilisation of RT was substantially lower than IRs derived from models. The assumptions from which these models were derived may result in over-estimates for resource planning purposes.

Complex valve disease: pre-surgical functional capacity evaluation using peak oxygen consumption

BACKGROUND AND AIM OF THE STUDY

Complex heart valve disease constitutes both mixed and multiple valve pathologies that coexist in a single heart. The chronicity of complex valve disease results in a slow decline in functional capacity. Currently, very few data exist relating to chronic complex valve disease. The clinical assessment of exertional dyspnea (NYHA class) is central to the decision to operate and predict a prognosis. Dyspnea causes significant functional limitations. Peak oxygen consumption (peak VO2) is the 'gold standard' of objectively measuring functional aerobic capacity, and is an important predictor of prognosis. The onset of dyspnea is the most common indication for valve surgery. The study aim, in patients with complex valve disease, was to: (i) objectively assess functional aerobic capacity using peak VO2; and (ii) compare the differences between NYHA classes I and II in relation to body composition, echocardiographic severity, and functional capacity

METHODS

A total of 45 patients with complex valve disease, who had been referred for the timing of surgery, was evaluated. The control group comprised 15 healthy subjects. All patients underwent a clinical assessment (to determine NYHA class), echocardiography and cardiopulmonary testing (peak VO2).

RESULTS

Patients with complex valve disease achieved significantly lower peak VO2 values than controls (16 +/- 5.9 versus 31.4 +/- 5.9 ml/kg/min; p = 0.0001). The peak VO2 (percentage predicted) was significantly different between asymptomatic (NYHA class I) patients (70.9 +/- 20%) and symptomatic (NYHA class II) patients (55.1 +/- 21%; p = 0.003), with an overlap between classes. There was no significant difference in the echocardiographic severity of the valve lesions between NYHA classes. In a multivariable regression analysis, the peak VO2 and VEN/VCO2 slope were powerful predictors of poor outcome (Hazards ratio 2.15, 5.62; p <0.05).

CONCLUSION

Patients with complex valve disease show significant functional capacity impairment, which may be difficult to detect from their clinical presentation. Consequently, peak VO2 measurements are required for the objective evaluation of functional capacity. The detection of a decline in peak VO2 will improve the timing of valve replacement and repair, and avoid adverse outcomes.

Lung cancer patients in New Zealand initially present to secondary care through the emergency department rather than by referral to a respiratory specialist

BACKGROUND

The previous study established that lung cancer patients in Auckland-Northland most commonly presented to secondary care through the emergency department (ED).

AIM

To further explore the characteristics and presentation of cases presenting through EDs in Auckland.

METHODS

Data were collected for all lung cancer cases (2004) in Auckland that initially presented to secondary care via ED RESULTS: Of (478) lung cancer cases diagnosed in Auckland in 2004, 170 cases (36%) presented via ED. ED presentation varied with tumour stage (p<0.0005), ethnicity (p=0.01), and DHB (p=0.004). Of the patients presenting to ED for whom records were available (159; 94%): 107 (67%) had respiratory symptoms; 66 (42%) were GP-referred; of these, 22 had had a CXR; 6 (4%) were already under respiratory surveillance; and 11 (6%) had previously been seen by secondary care regarding the presenting symptoms. All cases (except 1) were admitted. GP referral varied across DHBs (p=0.04) and ethnic groups (p=0.02). Age, gender, and tumour type were not associated with ED presentation.

CONCLUSION

Lung cancer patients, especially those of Pacific ethnicity, commonly presented as emergencies, often by-passing primary care. This suggests barriers to, or within, primary care and further research is required to explore the reasons underlying these findings.

Inhaled steroids for bronchiectasis

BACKGROUND

Bronchiectasis is increasingly recognized as a major cause of respiratory morbidity especially in developing countries and in some ethnic populations of affluent countries. It is characterized by irreversible dilatation of airways, generally associated with chronic bacterial infection. Medical management largely aims to reduce morbidity by controlling the symptoms and by preventing the progression of bronchiectasis.

OBJECTIVES

To evaluate the efficacy of inhaled corticosteroids (ICS) in children and adults with bronchiectasis (a) during stable bronchiectasis; and for reducing; (b) the severity and frequency of acute respiratory exacerbations and (c) long term pulmonary decline.

SEARCH STRATEGY

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialized Register Collaboration and Cochrane Airways Group, MEDLINE and EMBASE databases were searched by the Cochrane Airways Group. The latest searches were performed in September 2007.

SELECTION CRITERIA

All randomised controlled trials comparing ICS with a placebo or no medication. Children and adults with clinical or radiographic evidence of bronchiectasis were included, but patients with cystic fibrosis (CF) were excluded.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion.

MAIN RESULTS

There were no paediatric studies. Six adult studies fulfilled the inclusion criteria. Of the 303 randomised, 278 subjects completed the trials. In the short term group (ICS for less then 6 months duration), adults on huge doses of ICS (2g per day of budesonide equivalent) had significantly improved forced expiratory volume in the first second (FEV(1)), forced vital capacity (FVC), Quality of life (QOL) score and sputum volume but no significant difference in peak flow, exacerbations, cough or wheeze, when compared to adults in the control arm (no ICS). When only placebo-controlled studies were included, there were no significant difference between groups in all outcomes examined (spirometry, clinical outcomes of exacerbation or sputum volume etc). The single study on long term outcomes showed no significant effect of inhaled steroids in any of the outcomes.

AUTHORS' CONCLUSIONS

The present review indicates that there is insufficient evidence to recommend the routine use of inhaled steroids in adults with stable state bronchiectasis. While a therapeutic trial may be justified in adults with difficult to control symptoms and in certain subgroups, this has to be balanced with adverse events especially if high doses are used. No recommendation can be made for the use of ICS in adults during an acute exacerbation or in children (for any state) as there were no studies.