Amanda J Piper

Physiotherapy, Respiratory Medicine, Sleep Medicine

BAppSc, MEd, PhD
36.60

Publications

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    ABSTRACT: The role of gender and menopause in obstructive sleep apnea (OSA) is well known; however, no study has reported the impact of gender on the clinical presentation and the nocturnal respiratory events in patients with obesity hypoventilation syndrome (OHS). Therefore, we prospectively evaluated differences in the clinical characteristics of women and men with OHS in a large cohort of patients with OSA. During the study period, a total of 1,973 patients were referred to the sleep clinic with clinical suspicion of OSA. All patients underwent overnight polysomnography, during which time spirometry, arterial blood samples and thyroid tests were routinely obtained. Among 1,973 consecutive patients, 1,693 (617 women) were diagnosed with OSA, among whom 144 suffered from OHS (96 women). The prevalence of OHS among women and men was 15.6% and 4.5%, respectively (p<0.001). Women with OHS were significantly older than men with OHS (61.5±11.9yr vs. 49.1±12.5 yr, p<0.001). Although there were no significant differences between genders regarding symptoms, body mass index, spirometric data, or daytime PaCO2, women with OHS suffered significantly more from hypertension, diabetes and hypothyroidism. The prevalence of OHS was higher in postmenopausal (21%) compared to premenopausal (5.3%) women (p<0001). HCO3 and duration of SpO2 <90% were the only independent predictors of OHS. In conclusion, we report that among subjects referred to the sleep disorders clinic for evaluation of OSA, OHS is more prevalent in women than men and that women with OHS suffer from significantly more comorbidities. Postmenopausal women with OSA have the highest prevalence of OHS.
    No preview · Article · Feb 2016 · Journal of Sleep Research
  • Amanda J. Piper
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    ABSTRACT: The development of daytime respiratory failure due to obesity alone is referred to as obesity hypoventilation syndrome. People with this disorder have significantly poorer cardiovascular, social, and survival outcomes compared to the general population and to obese eucapnic individuals. Obesity hypoventilation arises from a complex interaction of factors related to obesity, pulmonary function, sleep-disordered breathing, and respiratory drive, and represents a failure of one or more of the usual mechanisms that maintain eucapnia despite obesity. Unfortunately, the presence of hypercapnia among those with obesity is often overlooked and intervention delayed, leading to increased morbidity and mortality. Treatment of sleep-disordered breathing is the mainstay of management. However, attention to other aspects of this disorder, including promotion of weight loss, reduction in sedentary behaviors, and maximizing control of cardiovascular comorbidities, is crucial in achieving significant and long-lasting improvements in quality of life and survival in these individuals.
    No preview · Chapter · Dec 2015
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    Amanda J Piper

    Full-text · Article · Sep 2015
  • Amanda Piper
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    ABSTRACT: Obesity hypoventilation syndrome (OHS) is becoming an increasingly encountered condition both in respiratory outpatient clinics and in hospitalized patients. The health consequences and social disadvantages of OHS are significant. Unfortunately, the diagnosis and institution of appropriate therapy is commonly delayed when the syndrome is not recognised or misdiagnosed. Positive airway pressure (PAP) therapy remains the mainstay of treatment and is effective in controlling sleep-disordered breathing and improving awake blood gases in the majority of individuals. Evidence supporting one mode of therapy over another is limited. Both continuous and bilevel therapy modes can successfully improve daytime gas exchange, with adherence to therapy an important modifiable factor in the response to treatment. Despite adherence to therapy, these individuals continue to experience excess mortality primarily due to cardiovascular events compared to those with eucapnic sleep apnea using CPAP. This difference likely arises from ongoing systemic inflammation secondary to the morbidly obese state. The need for a comprehensive approach to managing nutrition, weight and physical activity in addition to reversal of sleep-disordered breathing is now widely recognised. Future studies need to evaluate the impact of a more aggressive and comprehensive treatment plan beyond managing sleep-disordered breathing. The impact of early identification and treatment of sleep-disordered breathing on the development and reversal of cardiometabolic dysfunction also requires further attention.
    No preview · Article · Aug 2015 · Chest
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    ABSTRACT: During an acute exacerbation of cystic fibrosis, is non-invasive ventilation beneficial as an adjunct to the airway clearance regimen? Randomised controlled trial with concealed allocation and intention-to-treat analysis. Forty adults with moderate to severe cystic fibrosis lung disease and who were admitted to hospital for an acute exacerbation. Comprehensive inpatient care (control group) compared to the same care with the addition of non-invasive ventilation during airway clearance treatments from Day 2 of admission until discharge (experimental group). Lung function and subjective symptom severity were measured daily. Fatigue was measured at admission and discharge on the Schwartz Fatigue Scale from 7 (no fatigue) to 63 (worst fatigue) points. Quality of life and exercise capacity were also measured at admission and discharge. Length of admission and time to next hospital admission were recorded. Analysed as the primary outcome, the experimental group had a greater rate of improvement in forced expiratory volume in 1 second (FEV1) than the control group, but this was not statistically significant (MD 0.13% predicted per day, 95% CI -0.03 to 0.28). However, the experimental group had a significantly higher FEV1 at discharge than the control group (MD 4.2% predicted, 95% CI 0.1 to 8.3). The experimental group reported significantly lower levels of fatigue on the Schwartz fatigue scale at discharge than the control group (MD 6 points, 95% CI 1 to 11). There was no significant difference between the experimental and control groups in subjective symptom severity, quality of life, exercise capacity, length of hospital admission or time to next hospital admission. Among people hospitalised for an acute exacerbation of cystic fibrosis, the use of non-invasive ventilation as an adjunct to the airway clearance regimen significantly improves FEV1 and fatigue. ANZCTR 12605000437662. [Dwyer TJ, Robbins L, Kelly P, Piper AJ, Bell SC, Bye PTP (2015) Non-invasive ventilation used as an adjunct to airway clearance treatments improves lung function during an acute exacerbation of cystic fibrosis: a randomised trial.Journal of PhysiotherapyXX: XX-XX]. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Jun 2015
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    ABSTRACT: Sleep disorders in amyotrophic lateral sclerosis (ALS) present a significant challenge to the management of patients. Issues include the maintenance of adequate ventilatory status through techniques such as non-invasive ventilation, which has the ability to modulate survival and improve patient quality of life. Here, a multidisciplinary approach to the management of these disorders is reviewed, from concepts about the underlying neurobiological basis, through to current management approaches and future directions for research. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Jun 2015 · Sleep Medicine Reviews

  • No preview · Article · Mar 2015 · Respirology
  • Amanda Jane Piper · Carly Ann Hollier
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    ABSTRACT: Obesity hypoventilation syndrome (OHS) has become a common cause of chronic hypercapnic respiratory failure and is now the leading indication for home nocturnal noninvasive positive pressure ventilation (NPPV) in many countries. The presence of this disorder is often overlooked despite these individuals having frequent contact with health care services several years prior to the diagnosis being made. Once on effective therapy, significant improvements in awake gas exchange, symptoms, and quality of life can be achieved. Although nocturnal positive airway pressure (PAP) therapy is widely used, the most appropriate mode of therapy to manage this condition has yet to be determined. Even when adherence to therapy is high, complete correction of awake hypercapnic respiratory failure may not occur in some patients, highlighting that sleep-disordered breathing (SDB) is not the only factor contributing to underbreathing in OHS. In addition to nocturnal PAP therapy, strategies to promote weight loss and reduce sedentary behavior are crucial to minimize the substantial health and social impacts of this increasingly prevalent condition.
    No preview · Chapter · Jan 2015
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    Full-text · Dataset · Nov 2014
  • Amanda J Piper · Brendon J Yee
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    ABSTRACT: In patients with impaired inspiratory muscle function or altered respiratory system mechanics, an imbalance between load and capacity can arise. The ventilatory control system normally compensates for this by increasing drive to maintain adequate alveolar ventilation levels, thereby keeping arterial CO2 within its normal range. To reduce work of breathing, a pattern of reduced tidal volume and increased respiratory rate occurs. This pattern itself may eventually reduce effective ventilation by increasing dead space ventilation. However, the impact of sleep on breathing and its role in the development of diurnal respiratory failure is often overlooked in this process. Sleep not only reduces respiratory drive, but also diminishes chemoresponsiveness to hypoxia and hypercapnia creating an environment where significant alterations in oxygenation and CO2 can occur. Acute increases in CO2 load especially during rapid eye movement sleep can initiate the process of bicarbonate retention which further depresses ventilatory responsiveness to CO2. Treatment of hypoventilation needs to be directed toward factors underlying its development. Nocturnal noninvasive positive pressure therapy is the most widely used and reliable strategy currently available to manage hypoventilation syndromes. Although this may not consistently alter respiratory muscle strength or the mechanical properties of the respiratory system, it does appear to reset chemosensitivity by reducing bicarbonate, resulting in a more appropriate ventilatory response to CO2 during wakefulness. Not only is diurnal hypoventilation reduced with noninvasive ventilation, but quality of life, functional capacity and survival are also improved. However, close attention to how therapy is set up and used are key factors in achieving clinical benefits. © 2014 American Physiological Society. Compr Physiol 4: 1639-1676, 2014.
    No preview · Article · Oct 2014 · Comprehensive Physiology

  • No preview · Article · Sep 2014 · Sleep Medicine Clinics
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    ABSTRACT: Background: 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. Methods: We measured overnight polysomnography (PSG), arterial blood gases, and Epworth Sleepiness Scale in 55 severe SDB patients with obesity hypoventilation syndrome or overlap syndrome (COPD+ obstructive sleep apnea) before and ∼3 months after positive airway pressure (PAP) treatment. Quantitative EEG analyses were performed, and the Delta/ Alpha ratio was used as an indicator of EEG activation. Results: After the PAP treatment, these patients showed a significant decrease in their waking pCO(2), daytime sleepiness, as well as all key breathing/oxygenation parameters during sleep. Overnight Delta/Alpha ratio of EEG was significantly reduced. There is a significant cross-correlation between a reduced wake pCO(2), a faster (more activated) sleep EEG (reduced Delta/Alpha ratio) and reduced daytime sleepiness (all p < 0.05) with PAP treatment. Multiple regression analyses showed the degree of change in hypercapnia to be the only significant predictor for both ESS and Delta/ Alpha ratio. Conclusions: Hypercapnia is a key correlate of EEG activation and daytime sleepiness in hypercapnic SDB patients. The relationship between hypercapnia and sleepiness may be mediated by reduced neuro-electrical brain activity.
    Full-text · Article · May 2014 · Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine
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    ABSTRACT: BACKGROUND: 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.
    Full-text · Article · May 2014 · Cochrane database of systematic reviews (Online)
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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.
    No preview · Article · Jan 2014 · Respiratory Physiology & Neurobiology

  • No preview · Article · Jan 2014 · Sleep Medicine Clinics
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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.
    Full-text · Article · Nov 2013 · Thorax
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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.
    Full-text · Conference Paper · Oct 2013

  • No preview · Article · Aug 2013 · Thorax
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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.
    No preview · Article · May 2013 · Respiratory Physiology & Neurobiology
  • Neil D Eves · Yuanlin Song · Amanda Piper · Toby M Maher
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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.
    No preview · Article · Jan 2013 · Respirology

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