EMG in COPD - Factor Analysis
Condition: COPD
Study type: Observational

Summary: 
      Acute exacerbations of COPD contribute to significant morbidity and mortality in the United
      Kingdom (UK). The ability to assess response to treatment during exacerbations that require
      hospitalisation would allow clinicians to better risk stratify patients for higher or lower
      level in-patient or out-patient care. Current methods of detecting clinical deterioration are
      validated in general medical populations and may lack sensitivity and specificity in patients
      with respiratory morbidity. The use of respiratory muscle EMG to assess neural respiratory
      drive (NRD) has been demonstrated to be a predictor of readmission in patients admitted to
      hospital with COPD. The technique has been applied on 'spot' readings of limited duration due
      to the need for hand analysis of the data. It has been performed by a trained clinical
      physiologist who removed any interference data and standardised the data gathered. New
      automated software allows for longer periods of observation, mostly unsupervised, and as a
      result, the NRD measurements are more likely to be affected by various sources of
      variability. The influence of clinical and physiological factors as they occur during routine
      clinical management, such as administration of bronchodilator medication, time of day of
      readings or proximity to chest physiotherapy, are not yet understood. This trial is designed
      to gather data to better understand these relationships with NRD.
    

Detailed description: 
      Introduction Patients admitted to hospital with acute exacerbations of COPD are at risk of
      significant in-hospital morbidity and mortality. Current markers of treatment success involve
      the integration of basic physiological variables (respiratory rate, heart rate, oxygen
      saturations), clinical examination and patient reported symptoms changes. Whilst the use of
      these physiological parameters are gold standard there remains concern that patient
      deterioration is often not detected and escalated effectively. This has led to the
      development and implementation of a range of clinical physiological composite scores such as
      the medical early warning score or the National Health Service (NHS) early warning scores.
      However, these scores have been validated in general rather than specific populations and
      there are concerns regarding their use in respiratory patient groups.The use of the
      parasternal intercostal muscle EMG (EMGpara) has been reported to track clinical change and
      identify treatment failure during hospital admissions with acute exacerbations of COPD
      (AECOPD) in selected and unselected cohorts. In these pilot works measurements were taken on
      research equipment and data analysed individually by a trained physiologist. The clinical
      physiologist ensured standardisation of recording conditions such as proximity to medication,
      patient position, time of day and recent activity. The effect of such clinical and
      physiological factors on EMGpara was minimised by the operator with preventive measures, such
      as the control for the measurement time, the limitation of the recording duration and the
      exclusion of any artefactual changes in EMGpara. The development of automated software allows
      for frequent sampling and continuous monitoring, which will potentially permit earlier
      detection of clinical deterioration. With an automated system however, clinical and
      physiological factors need to be carefully considered, in particular when the measurement is
      performed in an unsupervised or less closely supervised environment. This feasibility study
      is therefore designed to investigate repeatability of EMGpara in hospital-based AECOPD
      management (i.e. EMGpara changes reflect changes in clinical status). It will give us insight
      into potential control/mitigation measures and their implementation, in order to ultimately
      minimise false readings.

      Study objectives To investigate the clinical and physiological factors that may affect the
      measurement of EMGpara in acute setting so as to enhance the clinical effectiveness of
      EMGpara in identifying treatment failure and clinical deterioration.
    

Intervention name(s): Neural Respiratory Drive Automated EMGpara assessment
Intervention type(s): Other
Intervention description(s): Neural respiratory drive will be measured using surface electrodes and nasal cannula . The 2nd intercostal space will be identified by bony landmarks and skin preparation will be performed using detergent wipes, followed by EMG preparation gel with final cleaning to remove exfoliated skin. Wet gel electrodes will be placed immediately adjacent to the sternal border in the 2nd intercostal space and will be connected to the automated EMG analysis system. Electrodes will remain in place for the duration of the study. A nasal cannula will be placed in the nose and detect pressure changes during respiration in order to ensure accurate detection of inspiratory cycle. In addition, an accelerometer will be attached to the thorax of the patient
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients admitted to St Thomas' Hospital with a primary diagnosis of an acute exacerbation
        of COPD.