Effect of lung volume on the oesophageal diaphragm EMG assessed by magnetic phrenic nerve stimulation

Luo, Yuan; Lyall, Rebecca; Harris, Mark; Hawkins, Peter G.; Hart, Nicholas; Polkey, Michael I.; Moxham, John

doi:10.1034/j.1399-3003.2000.01510.x

Cited by 16 publications

(23 citation statements)

References 19 publications

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“…Historically, such electrodes have been considered difficult to position with accuracy; indeed some investigators have considered it necessary to anchor the electrode with a gastric balloon in order to obtain adequate signals [13]. Since this anchoring gives an uncomfortable sensation and, by movement of the balloon with respiration, creates an additional artefact [14], it limits the usefulness of the technique for studies while patients are asleep.…”

Section: Significance Of the Findingsmentioning

confidence: 99%

Neural respiratory drive during apnoeic events in obstructive sleep apnoea

Luo

Hua²,

Jing³

et al. 2007

Eur Respir J

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For a given neural drive, oesophageal pressure during apnoeic episodes may differ from that during airflow, since inspiratory airflow and increased lung volume both reduce pressure generation. It was, therefore, hypothesised that diaphragm electromyography (EMG) may provide additional data to oesophageal pressure when used for the assessment of neural drive in patients with obstructive sleep apnoea, whose breathing is associated with variable airflow and changes in lung volume.Neural respiratory drive was assessed using diaphragm EMG recorded from multipair oesophageal electrodes in 12 patients with obstructive sleep apnoea. Oesophageal pressure was also recorded.The mean¡SD inspiratory oesophageal pressure swing was 11.0¡3.7 cmH 2 O during wakefulness, 38.2¡15.7 cmH 2 O at the end of the apnoea and reduced to 28.5¡10.4 cmH 2 O at the beginning of arousal. The mean peak inspiratory diaphragm EMG signal was 21.8¡6.5 mV during wakefulness, 38.6¡14.0 mV at the end of the apnoea and further increased to 59.6¡32.0 mV at the beginning of arousal.It was concluded that the pattern of neural drive assessed by oesophageal pressure differs from that measured by diaphragm electromyography during apnoeic events and, therefore, that diaphragm electromyography may be a useful adjunct to measurement of oesophageal pressure for the assessment of neural drive in patients with obstructive sleep apnoea.

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Section: Significance Of the Findingsmentioning

confidence: 99%

Neural respiratory drive during apnoeic events in obstructive sleep apnoea

Luo

Hua²,

Jing³

et al. 2007

Eur Respir J

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“…When in the optimal position, the electrode catheter was securely taped at the nose. No balloons or weights were used to anchor the catheter (Beck et al 1997;Luo et al 2000b). The sEMGpara was recorded using surface electrodes (Kendall Arbo R ; Tyco healthcare R , Neustadt, Germany).…”

Section: Measurementsmentioning

confidence: 99%

“…Understanding the effects of respiratory load on neural respiratory drive and the respiratory pattern are key to understanding the regulation of respiratory load compensation in respiratory disease. Recording the diaphragmatic electromyogram (EMGdi) using an oesophageal multipair electrode is a sensitive and reproducible method for the quantification of neural respiratory drive (NRD) in both healthy subjects and patients (Luo et al 2000 a , b , 2008; Jolley et al 2009; Reilly et al 2011). The EMGdi provides a measure of the load on the respiratory muscles (Jolley et al 2009; Murphy et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Neural respiratory drive measured during inspiratory threshold loading and acute hypercapnia in healthy individuals

Reilly¹,

Jolley²,

Ward³

et al. 2013

Experimental Physiology

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New Findings r What is the central question of this study?The aim of this study was to examine the relationship between neural respiratory drive (NRD) measured as the electromyogram of the diaphragm (EMGdi%max) and parasternal intercostal muscles (sEMGpara%max) during two different ventilatory loading strategies, namely acute hypercapnia and inspiratory threshold loading. We hypothesized that, although agonist in nature, there would be a preferential increase in NRD to the diaphragm over the parasternal intercostal muscles during the two different loading conditions, given their different mechanical advantages and relative contributions to ventilation. r What is the main finding and its importance?The sEMGpara%max provides a non-invasive alternative to EMGdi%max recorded using an invasive oesophageal electrode catheter for the quantification of NRD. The EMGdi%max was, however, consistently greater than sEMGpara%max during both loading protocols, demonstrating that these two measures of NRD are not interchangeable.Understanding the effects of respiratory load on neural respiratory drive and respiratory pattern are key to understanding the regulation of load compensation in respiratory disease. The aim of the study was to examine and compare the recruitment pattern of the diaphragm and parasternal intercostal muscles when the respiratory system was loaded using two methods. Twelve subjects performed incremental inspiratory threshold loading up to 50% of their maximal inspiratory pressure, and 10 subjects underwent incremental, steady-state hypercapnia to a maximal inspired CO 2 of 5%. The diaphragmatic electromyogram (EMGdi) was measured using a multipair oesophageal catheter, and the parasternal intercostal muscle EMG (sEMGpara) was recorded from bipolar surface electrodes positioned in the second intercostal space. The EMGdi and sEMGpara were analysed over the last minute of each increment of both protocols, normalized using the peak EMG recorded during maximal respiratory manoeuvres and expressed as EMG%max. The EMGdi%max and sEMGpara%max increased in parallel during the two loading methods, although EMGdi%max was consistently greater than sEMGpara%max in both conditions, inspiratory threshold loading [bias (

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“…Concerns about changes in lung volume on the diaphragm EMG have hampered the application of the oesophageal diaphragm EMG in clinical practice. Many studies [53,60,62,65,70,71] have tried to address the effect of lung volume on the amplitude of the diaphragm EMG by using different electrode design. It was hypothesized that a change in the amplitude of the diaphragm CMAP was due to alternations in the distance between the electrode and the diaphragm secondary to the change in lung volume during respiration [65].…”

Section: Effect Of Changes In Lung Volume On the Diaphragm Emgmentioning

confidence: 99%

“…They also observed that during deep breathing the electrode catheter could move up to 8 cm, which is beyond the maximal movement of the crus [61,70]. The large movement of the catheter during respiration suggested that the catheter with both a balloon and the weight was actually unable to reliably record the diaphragm EMG because the electrodes failed to track the movement of the crus of the diaphragm [70,71]. Previously, we have used a multipair oesophageal electrode with an interelectrode distance of 3 cm within a pair and found that changes in lung volume of up to 2 litres had little effect on the amplitude of the diaphragm CMAP, providing the oesophageal electrode catheter was optimally positioned and then fixed on the nose [71].…”

Section: Effect Of Changes In Lung Volume On the Diaphragm Emgmentioning

confidence: 99%

Diaphragm electromyography using an oesophageal catheter: current concepts

2008

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The usefulness of diaphragm electromyography recorded from an oesophageal electrode depends on a reliable signal which is free of artefact. The diaphragm EMG (electromyogram) recorded from chest wall surface electrodes may be unreliable because of signal contamination from muscle activity other than the diaphragm. Initially, the oesophageal electrode catheter for human studies had only one electrode pair, which could be difficult to position accurately and was influenced by a change in lung volume. Recently, a multipair oesophageal electrode has been developed which allows a high-quality EMG to be recorded. In the present review, the progress of oesophageal electrode design is outlined. The effects of signal contamination, electrode movement and particularly the effect of change in lung volume on the diaphragm EMG are discussed. The diaphragm EMG, recorded from a multipair oesophageal electrode, is useful to assess neural respiratory drive and diaphragm function in different groups of patients with respiratory disease, including patients with neuromuscular disease and sleep-disordered breathing, and those in the intensive care unit. When combined with cervical and cranial magnetic stimulation, an oesophageal electrode can be used to partition the central respiratory response time and phrenic nerve conduction time.

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Effect of lung volume on the oesophageal diaphragm EMG assessed by magnetic phrenic nerve stimulation

Cited by 16 publications

References 19 publications

Neural respiratory drive during apnoeic events in obstructive sleep apnoea

Neural respiratory drive during apnoeic events in obstructive sleep apnoea

Neural respiratory drive measured during inspiratory threshold loading and acute hypercapnia in healthy individuals

Diaphragm electromyography using an oesophageal catheter: current concepts

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