Influence of the bipolar electrode transfer function on the electromyogram power spectrum

Sinderby, Christer A.; Comtois, Alain Steve; Thomson, Richard; Grassino, A.

doi:10.1002/(sici)1097-4598(199603)19:3<290::aid-mus3>3.0.co;2-8

Cited by 24 publications

(12 citation statements)

References 18 publications

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“…Studies in animals have shown that the diaphragm EMG is related to phrenic nerve activity [53]. Studies in healthy subjects, patients with respiratory disorders, and mechanically ventilated critically ill patients show that EA di represents respiratory drive and that its amplitude and coupling to diaphragm force (transdiaphragmatic pressure) may vary because of, for example, anatomic variations and pathology [18-21,27-32,54-56]. Human motor-unit discharge rates are strongly associated with neural respiratory drive in both health and disease [57,58].…”

Section: Discussionmentioning

confidence: 99%

Neuroventilatory efficiency and extubation readiness in critically ill patients

Liu

Yang

et al. 2012

Crit Care

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IntroductionBased on the hypothesis that failure of weaning from mechanical ventilation is caused by respiratory demand exceeding the capacity of the respiratory muscles, we evaluated whether extubation failure could be characterized by increased respiratory drive and impaired efficiency to generate inspiratory pressure and ventilation.MethodsAirway pressure, flow, volume, breathing frequency, and diaphragm electrical activity were measured in a heterogeneous group of patients deemed ready for a spontaneous breathing trial. Efficiency to convert neuromuscular activity into inspiratory pressure was calculated as the ratio of negative airway pressure and diaphragm electrical activity during an inspiratory occlusion. Efficiency to convert neuromuscular activity into volume was calculated as the ratio of the tidal volume to diaphragm electrical activity. All variables were obtained during a 30-minute spontaneous breathing trial on continuous positive airway pressure (CPAP) of 5 cm H2O and compared between patients for whom extubation succeeded with those for whom either the spontaneous breathing trial failed or for those who passed, but then the extubation failed.ResultsOf 52 patients enrolled in the study, 35 (67.3%) were successfully extubated, and 17 (32.7%) were not. Patients for whom it failed had higher diaphragm electrical activity (48%; P < 0.001) and a lower efficiency to convert neuromuscular activity into inspiratory pressure and tidal volume (40% (P < 0.001) and 53% (P < 0.001)), respectively. Neuroventilatory efficiency demonstrated the greatest predictability for weaning success.ConclusionsThis study shows that a mixed group of critically ill patients for whom weaning fails have increased neural respiratory drive and impaired ability to convert neuromuscular activity into tidal ventilation, in part because of diaphragm weakness.Trial RegistrationClinicaltrials.gov identifier NCT01065428. ©2012 Liu et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Section: Discussionmentioning

confidence: 99%

Neuroventilatory efficiency and extubation readiness in critically ill patients

Liu

Yang

et al. 2012

Crit Care

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“…The amount of diaphragm electrical activity during each inspiration was quantified by using the methods of Beck et al (7-10) and Sinderby et al (54,56,57). These studies are the basis of several assumptions that are central to our analysis of Eff di .…”

Section: Critique Of Methods and Assumptionsmentioning

confidence: 99%

“…However, studies in dogs (50) and lambs (61) have shown a linear relationship between V O 2 di and the amount of diaphragm electrical activity. Beck et al (7)(8)(9)(10) and Sinderby et al (54,56,57) have developed and validated methods for accurately quantifying the amount of diaphragm electrical activity using multiple electrodes positioned in the esophagus to span the crural diaphragm. This method controls for diaphragm position (8,10,57) and signal contamination (54,56); electrical activity is quantified by the root mean square of the electromyogram (EMG) signals (RMS di ) and is an accurate index of global diaphragm activation (7,60).…”

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confidence: 99%

Efficiency of the normal human diaphragm with hyperinflation

Finucane¹,

Panizza²,

Singh³

2005

Journal of Applied Physiology

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We evaluated an index of diaphragm efficiency (Eff(di)), diaphragm power output (Wdi) relative to electrical activation, in five healthy adults during tidal breathing at usual end-expiratory lung volume (EELV) and diaphragm length (L(di ee)) and at shorter L(di ee) during hyperinflation with expiratory positive airway pressure (EPAP). Measurements were repeated with an inspiratory threshold (7.5 cmH(2)O) plus resistive (6.5 cmH(2)O.l(-1).s) load. Wdi was the product of mean inspiratory transdiaphragmatic pressure (DeltaPdi(mean)), diaphragm volume displacement measured fluoroscopically, and 1/inspiratory duration (Ti(-1)). Diaphragm activation, measured with esophageal electrodes, was quantified by computing root-mean-square values (RMS(di)). With EPAP, 1) EELV increased [mean r(2) = 0.91 (SD 0.01)]; 2) in four subjects, L(di ee) decreased [mean r(2) = 0.85 (SD 0.07)] and mean Eff(di) decreased 34% per 10% decrease in L(di ee) (P < 0.001); and 3) in one subject, gastric pressure at EELV increased two- to threefold, L(di ee) was unchanged or increased, and Eff(di) increased at two of four levels of EPAP (P < or = 0.006, ANOVA). Inspiratory loading increased Wdi (P = 0.003) and RMS(di) (P = 0.004) with no change in Eff(di) (P = 0.63) or its relationship with L(di ee). Eff(di) was more accurate in defining changes in L(di ee) [(true positives + true negatives)/total = 0.78 (SD 0.13)] than DeltaPdi(mean).RMS(di)(-1), RMS(di), or DeltaPdi(mean).Ti (all <0.7, P < or = 0.05, without load). Thus Eff(di) was principally a function of L(di ee) independent of inspiratory loading, behavior consistent with muscle force-length-velocity properties. We conclude that Eff(di), measured during tidal breathing and in the absence of expiratory muscle activity at EELV, is a valid and accurate measure of diaphragm contractile function.

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“…2). EAdi is not influenced by changes in muscle length, chest wall configuration, and/or lung volume [10][11][12] and correlates with phrenic nerve activity [13]. During NAVA the amount of applied pressure is coupled with the magnitude of the EAdi and the proportion of support pressure to EAdi (NAVA level) can be adjusted by the clinicians.…”

Section: Optimizing Child/ventilator Interaction: From Conventional Tmentioning

confidence: 99%

Mechanical ventilation for children

Conti

Piastra²

2016

Current Opinion in Critical Care

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Despite the improvement observed in the last decades in the treatment of pediatric acute respiratory failure and the diffusion of innovative modes of mechanical ventilation, there are no clear and consistent guidelines for the use of mechanical ventilation for children. In several areas data are still lacking, and in many others they are extrapolated from studies performed in adults; the direct evaluation of results obtained from studies specific to the pediatric population is therefore crucial.

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Influence of the bipolar electrode transfer function on the electromyogram power spectrum

Cited by 24 publications

References 18 publications

Neuroventilatory efficiency and extubation readiness in critically ill patients

Neuroventilatory efficiency and extubation readiness in critically ill patients

Efficiency of the normal human diaphragm with hyperinflation

Mechanical ventilation for children

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