Influence of asthma and obesity on respiratory load perception in children

...Introduction: Elevated symptom burden has been reported in concomitant asthma and overweight, although objective evidence of greater disease severity is lacking. This may reflect exaggerated symptom perception and has implications for optimal asthma management. Aims: To investigate respiratory load perception in overweight asthmatic (OA) children compared to normal weight asthmatic children (NWA) and healthy controls (HC). Methods: Incremental inspiratory resistive loading was performed in 27 children (9 OA, 9 NWA, 9 HC) with load perception assessed by visual analogue scale (VAS). Respiratory load was quantified via parasternal intercostal electromyography (EMGpara) expressed as neuroventilatory efficiency (NVE: ratio of tidal volume to EMGpara (ml/μV)). Linear mixed model analysis was used to examine changes in perception scores and NVE with increasing resistance, and to determine the influence of asthma and overweight. Results: VAS increased significantly with increasing resistance (slope (95% CI) 5.06 (1.83 – 8.29)mm/kPa/L/s, p=0.002), which was additionally influenced by degree of reduction in NVE (p=0.004). The slopes of these relationships did not differ with group, indicating no effect of asthma or overweight on either perception or objective response to increasing load. Weight had a significant effect on the intercept of the VAS/resistance relationship, with OA having a significantly higher intercept (9.96mm (95% CI 1.15 – 18.77), p=0.027), suggesting breathlessness at rest and higher VAS scores throughout. Conclusions: Respiratory load perception is not influenced by weight status. The increased symptom burden in overweight asthmatics may be related to elevated baseline respiratory load.Meeting abstract presented at European Respiratory Society International Congress, London, UK, 3-7 September 2016

Dance as a rehabilitative strategy for patients with COPD

Copyright © the authors 2017. Pulmonary rehabilitation (PR) is a highly effective intervention for COPD, though lack of enjoyment and preconceptions about exercise impact on uptake, completion and maintenance of physical activity post-PR. We piloted dance classes led by an experienced choreographer and a trained dancer as an exercise modality for 5 patients with COPD (61–76 years, 3 female, GOLD 2-3). The intervention, comprising 1 hour of stretching, posture, balance, coordination and strength exercises based on a variety of movement and dance techniques and styles at low to high intensity, was trialled in 1 session and refined over 2 further sessions. During the latter 2 sessions heart rate (HR) was recorded; dyspnoea and leg fatigue numerical rating scale (NRS) values taken at 4 points during the class; participants rated mood, sense of group cohesion and enjoyment. Peak HR reached 79-95% of predicted maximum, and was maintained above 70%max for median 26% of class duration. Individual participants’ peak NRS values for dyspnoea ranged from 4–9, and for leg fatigue from 4–8. All participants showed improved mood (from median (range) 5 (4-7) to 7 (5-7)), sense of group cohesion (6 (3-6) to 7 (5-7)), deemed the sessions worthwhile (7 (6-7)), and expressed enjoyment (7 (6-7)) and a sense of achievement (6 (3-7)) on completion. Qualitative data indicated participants underestimated class duration by up to 15%, and that concentration on technique helped divert attention away from dyspnoea. Expert-led dance sessions may provide a suitable intensity of training stimulus to improve strength and fitness in individuals with COPD, with potential wider psychosocial benefits. A larger randomised trial is warranted to compare dance-based exercise to conventional PR

Randomised sham-controlled trial of transcutaneous electrical stimulation in obstructive sleep apnoea

Introduction Obstructive sleep apnoea (OSA) is characterised by a loss of neuromuscular tone of the upper airway dilator muscles while asleep. This study investigated the effectiveness of transcutaneous electrical stimulation in patients with OSA. Patients and methods This was a randomised, sham-controlled crossover trial using transcutaneous electrical stimulation of the upper airway dilator muscles in patients with confirmed OSA. Patients were randomly assigned to one night of sham stimulation and one night of active treatment. The primary outcome was the 4% oxygen desaturation index, responders were defined as patients with a reduction >25% in the oxygen desaturation index when compared with sham stimulation and/or with an index <5/hour in the active treatment night. Results In 36 patients (age mean 50.8 (SD 11.2) years, male/female 30/6, body mass index median 29.6 (IQR 26.9–34.9) kg/m2, Epworth Sleepiness Scale 10.5 (4.6) points, oxygen desaturation index median 25.7 (16.0–49.1)/hour, apnoea-hypopnoea index median 28.1 (19.0–57.0)/hour) the primary outcome measure improved when comparing sham stimulation (median 26.9 (17.5–39.5)/hour) with active treatment (median 19.5 (11.6–40.0)/hour; p=0.026), a modest reduction of the mean by 4.1 (95% CI −0.6 to 8.9)/hour. Secondary outcome parameters of patients' perception indicated that stimulation was well tolerated. Responders (47.2%) were predominantly from the mild-to-moderate OSA category. In this subgroup, the oxygen desaturation index was reduced by 10.0 (95% CI 3.9 to 16.0)/hour (p<0.001) and the apnoea-hypopnoea index was reduced by 9.1 (95% CI 2.0 to 16.2)/hour (p=0.004). Conclusion Transcutaneous electrical stimulation of the pharyngeal dilators during a single night in patients with OSA improves upper airway obstruction and is well tolerated

Parasternal intercostal electromyography: A novel tool to assess respiratory load in children

Background: Parasternal intercostal muscle electromyography (EMGpara) represents a novel tool to assess respiratory load when volitional techniques are not possible. This study examined the application of EMGpara in healthy, wheezy, and critically ill children. Methods: Surface EMGpara was measured during tidal breathing in 92 healthy children, 20 wheezy preschool children (with measurements repeated following bronchodilator), and 25 mechanically ventilated children during supported ventilation and on continuous positive airways pressure.Results: EMGpara was related to age, height, and weight in the healthy group (r = -0.623, -0.625, -0.641 respectively, all P < 0.0001). An age-based equation for predicted EMGpara was developed and patient data expressed as z-scores. EMGpara was higher in wheezy children prebronchodilator than healthy controls (median interquartile range (IQR) z-score 0.53 (0.07-1.94), P = 0.0073), falling to levels not different to healthy children postbronchodilator (-0.08 (-0.50-1.00)). In the critically ill children, EMGpara was higher (P < 0.0001) than in healthy subjects during both mechanical ventilation (median (IQR) z-score 1.14 (0.33-1.93)) and continuous positive airways pressure (1.88 (0.91-3.03)).Conclusion: EMGpara is feasible in children and infants both healthy and diseased, is raised in those with elevated respiratory load, and is responsive to clinical interventions. EMGpara represents a potential method to assess respiratory status in patients conventionally challenging to assess

Parasternal intercostal muscle activity during methacholine-induced bronchoconstriction

V.M. was supported by Asthma U

Pulmonary function at follow up of very preterm infants from the United Kingdom Oscillation Study

Prematurely born infants supported by conventional ventilation frequently have abnormal pulmonary function when assessed in childhood. The aim of this study was to test the hypothesis that infants who were randomly assigned to high frequency oscillatory ventilation would have superior pulmonary function at follow-up to those who received conventional ventilation (United Kingdom Oscillation Study). Infants from 12 trial centres were recruited for pulmonary function testing at a single centre. Seventy-six infants, of mean gestational age 26.4 weeks, were studied following sedation with chloral hydrate at between 11 and 14 months of age, corrected for prematurity. Infants assigned to conventional ventilation had similar pulmonary function to those assigned to high frequency oscillatory ventilation, with mean (SD) results as follows: functional residual capacity measured by whole body plethysmography 26.9 (6.3) vs. 26.5 (6.4) ml/kg; functional residual capacity measured by helium dilution 24.1 (5.4) vs. 23.5 (5.7) ml/kg; inspiratory airway resistance 3.3 (1.3) vs. 3.4 (1.6) kPa/(l/s); expiratory airway resistance 4.4 (2.8) vs. 4.1 (2.5) kPa/(l/s); respiratory rate 31.2 (6.0) vs. 33.9 (8.0) breaths/minute. We conclude that early use of high frequency oscillatory ventilation in very preterm infants appears to offer no advantage over conventional ventilation in terms of pulmonary function at follow-u