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    ABSTRACT: Exercise training as a component of pulmonary rehabilitation improves health-related quality of life (HRQL) and exercise capacity in people with chronic obstructive pulmonary disease (COPD). However, some individuals may have difficulty performing exercise at an adequate intensity. Non-invasive ventilation (NIV) during exercise improves exercise capacity and dyspnoea during a single exercise session. Consequently, NIV during exercise training may allow individuals to exercise at a higher intensity, which could lead to greater improvement in exercise capacity, HRQL and physical activity. To determine whether NIV during exercise training (as part of pulmonary rehabilitation) affects exercise capacity, HRQL and physical activity in people with COPD compared with exercise training alone or exercise training with sham NIV. We searched the following databases between January 1987 and November 2013 inclusive: The Cochrane Airways Group specialised register of trials, AMED, CENTRAL, CINAHL, EMBASE, LILACS, MEDLINE, PEDro, PsycINFO and PubMed. SELECTION CRITERIA: Randomised controlled trials that compared NIV during exercise training versus exercise training alone or exercise training with sham NIV in people with COPD were considered for inclusion in this review. Two review authors independently selected trials for inclusion in the review, extracted data and assessed risk of bias. Primary outcomes were exercise capacity, HRQL and physical activity; secondary outcomes were training intensity, physiological changes related to exercise training, dyspnoea, dropouts, adverse events and cost. Six studies involving 126 participants who completed the study protocols were included. Most studies recruited participants with severe to very severe COPD (mean forced expiratory volume in one second (FEV1) ranged from 26% to 48% predicted). There was an increase in percentage change peak and endurance exercise capacity with NIV during training (mean difference in peak exercise capacity 17%, 95% confidence interval (CI) 7% to 27%, 60 participants, low-quality evidence; mean difference in endurance exercise capacity 59%, 95% CI 4% to 114%, 48 participants, low-quality evidence). However, there was no clear evidence of a difference between interventions for all other measures of exercise capacity. The results for HRQL assessed using the St George's Respiratory Questionnaire do not rule out an effect of NIV (total score mean 2.5 points, 95% CI -2.3 to 7.2, 48 participants, moderate-quality evidence). Physical activity was not assessed in any study. There was an increase in training intensity with NIV during training of 13% (95% CI 1% to 27%, 67 participants, moderate-quality evidence), and isoload lactate was lower with NIV (mean difference -0.97 mmol/L, 95% CI -1.58mmol/L to -0.36 mmol/L, 37 participants, moderate-quality evidence). The effect of NIV on dyspnoea or the number of dropouts between interventions was uncertain, although again results were imprecise. No adverse events and no information regarding cost were reported. Only one study blinded participants, whereas three studies used blinded assessors. Adequate allocation concealment was reported in four studies. The small number of included studies with small numbers of participants, as well as the high risk of bias within some of the included studies, limited our ability to draw strong evidence-based conclusions. Although NIV during lower limb exercise training may allow people with COPD to exercise at a higher training intensity and to achieve a greater physiological training effect compared with exercise training alone or exercise training with sham NIV, the effect on exercise capacity is unclear. Some evidence suggests that NIV during exercise training improves the percentage change in peak and endurance exercise capacity; however, these findings are not consistent across other measures of exercise capacity. There is no clear evidence that HRQL is better or worse with NIV during training. It is currently unknown whether the demonstrated benefits of NIV during exercise training are clinically worthwhile or cost-effective.
    Cochrane database of systematic reviews (Online) 05/2014; 5:CD007714. · 5.70 Impact Factor
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    ABSTRACT: Validation of respiratory inductive plethysmography (LifeShirt system) (RIPLS) for tidal volume (VT), minute ventilation (V˙E), and respiratory frequency (ƒB) was performed among people with untreated obesity hypoventilation syndrome (OHS) and controls. Measures were obtained simultaneously from RIPLS and a spirometer during two tests, and compared using Bland Altman analysis. Among 13 OHS participants (162 paired measures), RIPLS-spirometer agreement was unacceptable for VT: mean difference (MD) 3mL (3%); limits of agreement (LOA) -216 to 220mL (±36%); V˙E: MD 0.1L.min(-1) (2%); LOA -4.1 to 4.3L.min(-1) (±36%); and ƒB: MD 0.2br.min(-1) (2%); LOA -4.6 to 5.0br.min(-1) (±27%). Among 13 controls (197 paired measures), RIPLS-spirometer agreement was acceptable for ƒB: MD -0.1br.min(-1) (-1%); LOA -1.2 to 1.1br.min(-1) (±12%), but unacceptable for VT: MD 5mL (1%); LOA -160 to 169mL (±20%) and V˙E: MD 0.1L.min(-1) (2%); LOA -1.4 to 1.5L.min(-1) (±20%). RIPLS produces valid measures of ƒB among controls but not OHS patients, and is not valid for quantifying respiratory volumes among either group.
    Respiratory Physiology & Neurobiology 01/2014; · 2.05 Impact Factor
  • Sleep Medicine Clinics 01/2014;
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    ABSTRACT: The key determinants of daytime drowsiness in sleep disordered breathing (SDB) are unclear. Hypercapnia has not been examined as a potential contributor due to the lack of reliable measurement during sleep. To overcome this limitation, we studied predominantly hypercapnic SDB patients to investigate the role of hypercapnia on EEG activation and daytime sleepiness.
    Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 01/2014; 10(5):517-22. · 2.93 Impact Factor
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    ABSTRACT: In people with obesity hypoventilation syndrome (OHS), breathing 100% oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98-100%. After 20 min of FiO2 0.28, PavCO2 change (ΔPavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5% (p=0.012). FiO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3% (p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ΔVE and ΔPavCO2 (r=-0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.
    Thorax 11/2013; · 8.38 Impact Factor
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    ABSTRACT: Introduction: Over the past three decades, non-invasive ventilation (NIV) has emerged as a core therapy in the management of acute respiratory failure both inside and outside intensive care. The aim of this study was develop a guideline for inpatient adults in public hospitals. Aim: The aim of the guideline group was to develop a list of recommendations to guide clinicians across NSW in the management of adult patients requiring NiPPV in various units including Intensive Care (ICU), High Dependency (HDU) and Specialised Respiratory Units. Method: A group of clinical experts based in ICU, HDU and specialised respiratory units from across NSW formed a guideline development group along with representatives from ICCMU and ACI. An extensive literature search/review, along with a clinical practise survey at 39 sites (incorporating current practice, policy, guidelines and work instructions) was conducted. A total of thirteen (13) recommendation statements focused on Indications/Contraindications, Assessment, Interface (mask) selection, Initiation and Titration of therapy, Humidification, Patient comfort and Compliance, Escalation of Therapy, Palliation, Nursing Care, Nutrition and Hydration, Infection Prevention, Environment and location of care and Staffing Ratios were considered. Results: The last group meeting was completed in June 2013 resulting in group consensus and development of 45 recommendations related to the care of the adult patient in acute respiratory failure requiring NiPPV.
    ANZICS/ACCCN Intensive Care ASM, Hobart, Australia; 10/2013
  • Thorax 08/2013; · 8.38 Impact Factor
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    ABSTRACT: This prospective study investigated the validity of arterialised-venous blood gases (AVBG) for estimating arterial carbon dioxide [Formula: see text] , pH and bicarbonate (HCO3(-)) in people with obesity hypoventilation syndrome (OHS). AVBGs were obtained from an upper limb vein, after heating the skin at 42-46°C. Arterial blood gas (ABG) and AVBG samples were taken simultaneously and compared using Bland Altman analysis. Between-group differences were assessed with independent t-tests or Mann-Whitney U tests. Forty-two viable paired samples were analysed, including 27 paired samples from 15 OHS participants, and 15 paired samples from 16 controls. AVBG-ABG agreement was not different between groups, or between dorsal hand, forearm and antecubital AVBG sampling sites, and was clinically acceptable for [Formula: see text] : mean difference (MD) 0.4mmHg (0.9%), limits of agreement (LOA) -2.7 to 3.6mmHg (±6.6%); pH: MD -0.008 (-0.1%), LOA -0.023 to 0.008 (±0.2%); and HCO3(-): MD -0.3 mmol.L(-1) (-1.0%), LOA -1.8 to 1.2 mmol.L(-1) (±5.3%). AVBG provides valid measures of [Formula: see text] , pH, and HCO3(-) in OHS.
    Respiratory Physiology & Neurobiology 05/2013; · 2.05 Impact Factor
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    ABSTRACT: The incremental changes made in the definition of ALI/ARDS over the last two decades represent a series of landmark events in the history of the condition. The first description of ARDS (Adult Respiratory Distress Syndrome) established the recognition of this syndrome(1) ; the 1994 AECC (America-European Consensus Conference) definition set the standard for ALI/ARDS clinical trials(2) ; while the new Berlin definition, which has revised the AECC version, is based on 18 years clinical investigation and mechanism exploration, and as a result is a more precise and practical(3) guide for clinical evaluation. The essential components of the new Berlin definition of ARDS are: removal of ALI and division of ARDS into three successive stages (mild, moderate and severe) based on timing, chest imaging, PaO(2) /FiO(2) ratio and level of PEEP applied, with, as previously, exclusion of heart failure or fluid overload. The new definition is based on two large scale databases from 7 medical centers and unifies the understanding of ARDS and establishes a new standard for future clinical trials.
    Respirology 01/2013; · 2.78 Impact Factor
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    Amanda J Piper
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    ABSTRACT: In the past few decades, obesity has emerged as a significant individual and public health issue. Estimates of obesity rates in adults have doubled over the past 20 years in many countries,(1 ) with this phenomenon occurring not only in western nations and amongst adults, but increasingly in developing economies and amongst children. The health consequences of being overweight or obese are significant, and worsen with increasing weight, reducing life expectancy(2) and impairing health related quality of life.(3) © 2012 The Author. Respirology © 2012 Asian Pacific Society of Respirology.
    Respirology 08/2012; · 2.78 Impact Factor
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    ABSTRACT: This study aims to describe the pattern of home mechanical ventilation (HMV) usage in Australia and New Zealand.Thirty-four centres providing HMV in the region were identified and asked to complete a questionnaire regarding centre demographics, patient diagnoses, HMV equipment and settings, staffing levels and methods employed to implement and follow-up therapy.Twenty-eight centres (82%) responded providing data on 2725 patients. The minimum prevalence of HMV usage was 9.9 patients per 100,000 population in Australia and 12.0 patients per 100,000 population in New Zealand. Variation existed across Australian states (range 4-13 patients per 100,000 population) correlating with population density (r=0.82, p<0.05). The commonest indications for treatment were obesity hypoventilation syndrome (OHS) (31%) and neuromuscular disease (NMD) (30%). OHS was more likely to be treated in New Zealand, in smaller, newer centres, whilst NMD was more likely to be treated in Australia, in larger, older centres. COPD was an uncommon indication (8.0%). No consensus on indications for commencing treatment was found.In conclusion, the prevalence of HMV usage varies across Australia and New Zealand according to centre location, size and experience. These findings can assist HMV service planning locally and highlight trends in usage that may be relevant in other countries.
    European Respiratory Journal 05/2012; · 6.36 Impact Factor
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    Respirology 01/2012; 17(3):554-62. · 2.78 Impact Factor
  • Amanda J Piper
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    ABSTRACT: Daytime hypercapnia that develops in morbidly obese individuals in the absence of concurrent lung or neuromuscular disease is referred to as the obesity hypoventilation syndrome (OHS). The characteristic polysomnographic (PSG) abnormality is marked sleep hypoxemia. Although the likelihood of hypoventilation increases with increasing body mass index (BMI), it is too simplistic to think of this disorder arising merely from chest wall restriction due to excess weight. Rather, this is a disorder which emerges when the compensatory mechanisms that normally operate to maintain ventilation appropriate for the level of obesity are impaired. OHS develops from a complex interaction between abnormal respiratory function, sleep disordered breathing and diminished respiratory drive. Irrespective of the mechanisms underlying the development of this disorder, early recognition of the problem and institution of effective therapy is important to reduce the significant clinical and societal repercussions of OHS. While therapy directed at improving sleep disordered breathing is effective in reversing daytime respiratory failure, it is not universally successful and information regarding longer term clinical outcomes is limited. Attention to weight reduction strategies are also necessary to reduce comorbid conditions and improve quality of life, but data regarding how successful and sustained this is in obesity hypoventilation are sparse.
    Sleep Medicine Reviews 04/2011; 15(2):79-89. · 8.68 Impact Factor
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    ABSTRACT: Slow wave sleep (SWS) has been theorized as reflecting a homeostatic sleep process and is considered a state of recuperation. SWS is reduced in obstructive sleep apnea (OSA) patients, but SWS has not been specifically studied in respiratory failure patients. The aim of this study is to investigate SWS in predominantly hypercapnic respiratory failure patients. We analyzed sleep and arterial blood gas records of all 97 respiratory failure patients who underwent polysomnography and bilevel non-invasive ventilation (NIV) treatment in our laboratory from 2008 to July 2009. We also analyzed 32 initial diagnostic study data from these 97 patients. The 97 patients had an average age of 58±15 (SD) years. Total sleep time was 320.3±82.8 (SD) min of which 32.9%±15.4 (%) was spent in SWS. This high percentage SWS correlated positively with awake arterial CO(2) pressure (PCO(2)) in both the 97 treatment studies (r=0.35, p=0.001) and the 32 initial diagnostic studies (r=0.40, p=0.025). The relationship was particularly apparent in patients with obesity hypoventilation syndrome or overlap syndrome. Statistical modelling identified three significant predictor variables for SWS across both diagnostic and NIV nights: PCO(2), arousal index and female gender. Patients with respiratory failure have a high percentage of EEG assessed SWS which is in part determined by disease specific variables such as hypercapnia as well as by traditional SWS determinants such as sleep fragmentation and gender.
    Sleep Medicine 03/2011; 12(4):378-83. · 3.49 Impact Factor
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    Amanda J Piper, Ronald R Grunstein
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    ABSTRACT: Obesity hypoventilation syndrome describes the association between obesity and the development of chronic daytime alveolar hypoventilation. This syndrome arises from a complex interaction between sleep-disordered breathing, diminished respiratory drive, and obesity-related respiratory impairment, and is associated with significant morbidity and mortality. Therapy directed toward reversing these abnormalities leads to improved daytime breathing, with available treatment options including positive pressure therapy, weight loss, and pharmacological management. However, a lack of large-scale, well-designed studies evaluating these various therapies has limited the development of evidence-based treatment recommendations. Although treatment directed toward improving sleep-disordered breathing is usually effective, not all patients tolerate mask ventilation and awake hypercapnia may persist despite effective use. In the longer term, weight loss is desirable, but data on the success and sustainability of this approach in obesity hypoventilation are lacking. The review outlines the major mechanisms believed to underlie the development of hypoventilation in this subgroup of obese patients, their clinical presentation, and current therapy options.
    American Journal of Respiratory and Critical Care Medicine 10/2010; 183(3):292-8. · 11.04 Impact Factor
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    ABSTRACT: Respiratory muscle strength is used diagnostically in clinical practice and as an outcome measure in clinical trials in various chronic lung diseases. There is limited data on its repeatability in people with non-CF bronchiectasis. The aim of the present study was to assess the repeatability of maximal inspiratory (P( I)max) and expiratory pressures (P(E)max) in a group of patients with stable, moderate-to-severe non-CF bronchiectasis. Twenty participants with stable moderate-to-severe non-CF bronchiectasis were recruited. Respiratory muscle strength measurements (three maximal inspiratory and expiratory pressures) were made on 2 separate days. A standard protocol was used, including practice tests, before obtaining three technically acceptable and reproducible readings with a difference of 10% or less between values. Clinical trial registration number: ClinicalTrials.gov: NCT00487149. The mean (SD) age of the non-CF bronchiectasis group was 63 (9) years. Maximal inspiratory pressures were repeatable with mean (SD) for highest P(I)max, Test 1 and Test 2, 75.90 (20) and 79.40 (19) cmH(2)O, and limits of agreement (mean difference +/- 2SD) -3.50 +/- 20 cmH(2)O, (p = 0.14). Maximal expiratory pressures differed significantly with mean (SD) for highest P(E)max, Test 1 and Test 2, 102.25 (27) and 112.30 (32) cmH(2)O, and limits of agreement (mean difference +/- 2SD) -10.10 +/- 35 cmH(2)O, (p = 0.02). The intraclass correlation coefficient (95% CI) for highest P(I)max and P(E)max was 0.93 (95% CI 0.82 to 0.97) and 0.90 (95% CI 0.76 to 0.96), respectively. Maximal inspiratory pressure measurements were repeatable during a period of clinical stability in moderate-to-severe non-CF bronchiectasis, suggesting this may be a useful outcome measure in non-CF bronchiectasis. Once a baseline has been established, a second visit is not required. P(E)max was not a repeatable measure and further study is necessary to ascertain how much practice testing is required to obtain an accurate value.
    Chronic Respiratory Disease 08/2010; 7(3):165-71.
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    ABSTRACT: To determine whether the level of pressure support (PS) provided during exercise influences endurance time in people with severe kyphoscoliosis, a double-blind randomised crossover study was performed. We hypothesised that high-level PS would be required to enhance endurance time in this population with high impedance to inflation. 13 participants with severe kyphoscoliosis performed four endurance treadmill tests in random order: unassisted; with sham PS; low-level PS of 10 cmH(2)O (PS 10); and high-level PS of 20 cmH(2)O (PS 20). Participants and assessors were blinded to the level of PS delivered during exercise. Endurance time was greater with PS 20 (median (interquartile range) 217 (168-424) s) compared with unassisted exercise (139 (111-189) s), sham PS (103 (88-155) s) and PS 10 (159 (131-206) s). In addition, isotime respiratory rate was decreased by 8 breaths x min(-1) (95% CI -11- -5 breaths x min(-1)) and isotime oxygen saturation increased by 4% (95% CI 1-7%) with PS 20 compared with unassisted exercise. People with severe kyphoscoliosis require high-level PS during walking to improve exercise performance. Investigation of high-level PS as an adjunct to exercise training or to assist in the performance of daily activities is warranted.
    European Respiratory Journal 08/2010; 36(2):370-8. · 6.36 Impact Factor
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    Amanda J Piper
    Respirology 02/2010; 15(2):191-3. · 2.78 Impact Factor
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    Amanda J Piper
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    ABSTRACT: Nocturnal hypoventilation is a common feature of disorders affecting the function of the diaphragm or central respiratory drive mechanisms. The ensuing change in gas exchange is initially confined to rapid eye movement (REM) sleep, but over time buffering of the raised carbon dioxide produces a secondary depression of respiratory drive that will further reduce ventilation not only during sleep but eventually during wakefulness as well. Failure to identify and treat nocturnal hypoventilation results in impairments in daytime function, quality of life and premature mortality. While some simple daytime tests of respiratory function can identify at risk individuals, these cannot predict the nature or severity of any sleep disordered breathing present. Nocturnal monitoring of gas exchange with or without full polysomnography is the only way to comprehensively assess this disorder, especially in the early stages of its evolution. Non invasive ventilation used during sleep is the most appropriate approach to reverse the consequences of nocturnal hypoventilation, although continuous positive airway pressure (CPAP) may be effective in those individuals where a significant degree of upper airway obstruction is present. When appropriately selected patients use therapy on a regular basis, significant improvements in quality of life, exercise capacity and survival can be achieved, irrespective of the underlying disease process.
    The Indian Journal of Medical Research 02/2010; 131:350-65. · 2.06 Impact Factor
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    Amanda Piper
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    ABSTRACT: Obesity hypoventilation syndrome occurs in obese individuals who are unable to compensate for the added load of obesity on the respiratory system, with resultant daytime hypercapnia in the absence of other causes of alveolar hypoventilation. Significant morbidity and mortality is seen in this disorder if appropriate treatment is not undertaken. Unfortunately, the diagnosis is frequently missed despite these individuals being heavy users of healthcare resources. The pathogenesis of obesity hypoventilation syndrome is multifactorial, but reversal of sleep-disordered breathing or significant weight loss improves respiratory function and daytime ventilation. However, a paucity of well-designed clinical trials and the absence of data from long-term follow-up means that comparison between various treatment options is not possible. Consequently, evidence-based treatment guidelines are currently lacking.
    Expert Review of Respiratory Medicine 02/2010; 4(1):57-70.

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