Paul Leong

Abnormal vocal cord movement treated with botulinum toxin in patients with asthma resistant to optimised management

Abnormal vocal cord movement may coexist with asthma and cause additional upper/middle airway obstruction. The condition may be a form of muscular dystonia that could contribute to asthma resistant to optimised treatments. Botulinum toxin causes temporary paralysis of muscle and may be an effective local treatment that improves asthma control.

Loop Gain Predicts the Response to Upper Airway Surgery in Patients With Obstructive Sleep Apnea

Study Objectives Upper airway surgery is often recommended to treat patients with obstructive sleep apnea (OSA) who cannot tolerate continuous positive airways pressure. However, the response to surgery is variable, potentially because it does not improve the nonanatomical factors (ie, loop gain [LG] and arousal threshold) causing OSA. Measuring these traits clinically might predict responses to surgery. Our primary objective was to test the value of LG and arousal threshold to predict surgical success defined as 50% reduction in apnea-hypopnea index (AHI) and AHI <10 events/hour post surgery. Methods We retrospectively analyzed data from patients who underwent upper airway surgery for OSA (n = 46). Clinical estimates of LG and arousal threshold were calculated from routine polysomnographic recordings presurgery and postsurgery (median of 124 [91-170] days follow-up). Results Surgery reduced both the AHI (39.1 ± 4.2 vs. 26.5 ± 3.6 events/hour; p < .005) and estimated arousal threshold (-14.8 [-22.9 to -10.2] vs. -9.4 [-14.5 to -6.0] cmH2O) but did not alter LG (0.45 ± 0.08 vs. 0.45 ± 0.12; p = .278). Responders to surgery had a lower baseline LG (0.38 ± 0.02 vs. 0.48 ± 0.01, p < .05) and were younger (31.0 [27.3-42.5] vs. 43.0 [33.0-55.3] years, p < .05) than nonresponders. Lower LG remained a significant predictor of surgical success after controlling for covariates (logistic regression p = .018; receiver operating characteristic area under curve = 0.80). Conclusions Our study provides proof-of-principle that upper airway surgery most effectively resolves OSA in patients with lower LG. Predicting the failure of surgical treatment, consequent to less stable ventilatory control (elevated LG), can be achieved in the clinic and may facilitate avoidance of surgical failures.

Dynamic laryngeal narrowing in COPD may have effects on the trachea

Dear Editor, Dyspnoea and exercise intolerance in patients with COPD have a wide variety of aetiologies, with dynamic hyperinflation and resultant loss in inspiratory reserve volume recognised as important mechanisms. Baz et al 1 show that dynamic laryngeal narrowing is present in patients with COPD and hypothesise that this generates intrinsic positive end-expiratory pressure (PEEPi), serving to ‘splint’ open …

Ventilatory control sensitivity in patients with obstructive sleep apnea is sleep stage dependent

Study Objectives The severity of obstructive sleep apnea (OSA) is known to vary according to sleep stage; however, the pathophysiology responsible for this robust observation is incompletely understood. The objective of the present work was to examine how ventilatory control system sensitivity (i.e. loop gain) varies during sleep in patients with OSA. Methods Loop gain was estimated using signals collected from standard diagnostic polysomnographic recordings performed in 44 patients with OSA. Loop gain measurements associated with nonrapid eye movement (NREM) stage 2 (N2), stage 3 (N3), and REM sleep were calculated and compared. The sleep period was also split into three equal duration tertiles to investigate how loop gain changes over the course of sleep. Results Loop gain was significantly lower (i.e. ventilatory control more stable) in REM (Mean ± SEM: 0.51 ± 0.04) compared with N2 sleep (0.63 ± 0.04; p = 0.001). Differences in loop gain between REM and N3 (p = 0.095), and N2 and N3 (p = 0.247) sleep were not significant. Furthermore, N2 loop gain was significantly lower in the first third (0.57 ± 0.03) of the sleep period compared with later second (0.64 ± 0.03, p = 0.012) and third (0.64 ± 0.03, p = 0.015) tertiles. REM loop gain also tended to increase across the night; however, this trend was not statistically significant [F(2, 12) = 3.49, p = 0.09]. Conclusions These data suggest that loop gain varies between REM and NREM sleep and modestly increases over the course of sleep. Lower loop gain in REM is unlikely to contribute to the worsened OSA severity typically observed in REM sleep, but may explain the reduced propensity for central sleep apnea in this sleep stage.

What's in a name? Expiratory tracheal narrowing in adults explained

Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions.

Clinical efficacy of virtual reality for acute procedural pain management: A systematic review and meta-analysis

Background Acutely painful procedures are commonplace. Current approaches to pain most often involve pharmacotherapy, however, there is interest in virtual reality (VR) as a non-pharmacological alternative. A methodologically rigorous systematic review and meta-analysis is lacking. Methods Following PRISMA guidelines, we searched the Cochrane Library, Ovid MEDLINE, Embase, CINAHL, ERIC, NIHR Centre for Review and Dissemination, Proquest, the System for Information on Grey Literature in Europe and the WHO International Clinical Trials Registry Platform from inception to 5 November 2017. Included studies were randomised with an experimental trial design, included a non-VR control group and examined the efficacy of VR with regards to an acutely painful clinical intervention. Bias was assessed along Cochrane guidelines, with performance bias not assessed due to the non-blindable nature of VR. We extracted summary data for maximal pain score and used standard mean difference DerSimonian-Laird random-effects meta-analysis (RevMan 5.3). This review was prospectively registered (PROSPERO CRD42017058204). Findings Of the 12,450 studies identified, 20 studies were eligible for the systematic review. No trials reported in sufficient detail to judge their risk of bias, and 10 studies were at high risk of bias in at least one domain. 16 studies (9 randomised controlled trials, 7 crossover studies) examining 656 individuals were included in quantitative synthesis. Pain scales were heterogenous, but mostly employed 100-point scales. Across all trials, meta-analysis was suggestive of a -0.49 (95%CI -0.83 to -0.41, p = 0.006) standardised mean difference reduction in pain score with VR. However there was a high degree of statistical heterogeneity (χ2 p<0.001, I2 81%, 95%CI for I2 70–88%), driven by randomised studies, with substantial clinical heterogeneity. Conclusion These data suggest that VR may have a role in acutely painful procedures, however included studies were clinically and statistically heterogenous. Further research is required to validate findings, establish cost efficacy and optimal clinical settings for usage. Future trials should report in accordance with established guidelines.

Loop Gain Predicts Response to Upper Airway Surgery for Obstructive Sleep Apnoea

007 EFFECTS OF 1 MONTH OF NIGHTLY ZOPICLONE ON OBSTRUCTIVE SLEEP APNOEA SEVERITY AND MEASURES OF ALERTNESS: A RANDOMISED CONTROLLED TRIAL S. CARTER, J. CARBERRY, L. FISHER, G. CHO, C. ROLLO, D. STEVENS, A. D’ROZARIO, D. MCKENZIE, R. GRUNSTEIN AND D. ECKERT Neuroscience Research Australia, The University of New South Wales, Woolcock Institute of Medical Research, The University of Sydney, Prince of Wales Hospital, Sydney, NSW, Australia Introduction: Hypnotics have historically not been recommended in obstructive sleep apnoea (OSA) due to concerns they may worsen OSA severity via pharyngeal muscle relaxation and arousal suppression. However, recent physiology studies: 1) do not show systematic impairment in upper airway muscle activity with certain hypnotics and 2) indicate that hypnotics worsen OSA in some patients and reduce OSA severity in others depending on the patient’s arousal threshold and severity of nocturnal hypoxaemia. However, clinical trial data is lacking. Accordingly, this study aimed to determine the effects of 1 month of nightly zopiclone on OSA severity and measures of alertness in OSA patients who have low-moderate respiratory arousal thresholds and mild overnight hypoxaemia. Methods: Initially, a screening physiology night to quantify the respiratory arousal threshold (nadir epiglottic pressure just prior to arousal) and nadir arterial blood oxygen saturation (SaO2) was performed. Thirty OSA patients (apnoea/hypopnoea index [AHI] = 22.4 11.3/h) with low-moderate arousal thresholds (> 25 cm H2O) and nadir SaO2 ≥ 75% were then studied in-lab (PSG) on three occasions at baseline, night 1 and night 30. Participants received either nightly zopiclone (7.5 mg) or placebo during the 30 day study according to a double-blind, randomised, parallel design. Subjective sleepiness (ESS and KSS) and a 30 min driving simulator task (AusEd) were performed following each PSG. Results: The median reduction in AHI on night 30 from baseline was 23 [ 4.47]% during zopiclone vs. 12 [ 8.29]% during placebo (P > 0.05). Change in mean SaO2 from baseline to night 30 was not different between zopiclone and placebo ( 0.1 0.7 vs. 0.1 1.4%). Similarly, neither the change in ESS ( 1.3 2.7 vs. 0.2 2.4), KSS (0 [ 1.0, 1.5] vs. 0 [ 1.0, 1.3]), or steering deviation (7.1 [ 1.3, 40.8] vs. 9.4 [ 20.6, 34.8]) during the AusEd driving task differed from baseline to night 30 during zopiclone vs. placebo. Conclusions: A standard dose of nightly zopiclone does not worsen OSA severity, next day sleepiness or alertness during a simulated driving task in OSA patients who have low to moderate arousal thresholds and nadir overnight SaO2 ≥ 75%. These findings challenge previous assumptions that hypnotics worsen OSA. 008 BRIEF SLEEP PSYCHOEDUCATION PROGRAM IMPROVES SLEEP QUALITY AND REDUCES INSOMNIA SYMPTOMS IN NEW MOTHERS L. KEMPLER, L. SHARPE AND D. BARTLETT Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia Sleep in the postpartum period is fragmented and often difficult. Infants wake frequently in the early weeks of life requiring care and attention. Increased sleep disturbance is associated with mood disorders and postnatal depression. The aim of this randomised controlled trial was to determine whether a brief sleep psychoeducation program delivered to mothers during their third trimester of pregnancy with their first baby could improve sleep and, if so, mood outcomes in the postnatal period. Method: Two hundred and fifteen mothers were randomised to receive either 2 9 1.5 h slide presentations with a set of sleep & relaxation booklets or general sleep booklets only. Participants were followed up with phone calls at 3 & 6 weeks postpartum and with questionnaires at 6 weeks, 4 months and 10 months postpartum. A Subgroup of participants wore an actiwatch for a week during their third trimester and for a week at 4 months postpartum. The primary outcome was sleep measured by sleep quality (PSQI), Insomnia, (ISI), sleepiness (ESS) and fatigue (MAF). The secondary outcome was mood measured using Edinburgh Postnatal Depression Scales (EPDS) and the depression subscale of the Depression Anxiety and Stress Scales (DASS). Results: A linear mixed model analysis was used for each factor (PSQI, ISI, ESS and MAF) at each time point (baseline, 6 week, 4 months, 10 months). Results indicated better sleep quality (mean difference 1.27; 95% CI [0.12 to 2.41] P = 0.032) and fewer insomnia symptoms (mean difference 1.55; 95% CI [1.66 to 2.93]; P = 0.028) at 4 months postpartum in the intervention group than the control group. There were no group differences in sleepiness, fatigue or mood outcomes, nor at other time-points. Conclusions: These results suggest that there is some short-term benefit of this intervention for women around 4 months postpartum. Given the low cost associated with this intervention, its inclusion in routine antenatal classes could hasten improvements in mothers’ sleep. a 2016 The Authors Journal of Sleep Research