Diaphragm Activation during Exercise in Chronic  Obstructive Pulmonary Disease

Sinderby, Christer A.; Spahija, Jadranka; Beck, Jennifer; Kaminski, Darek; Shi, Yan; Comtois, Norman; Śliwiński, Paweł

doi:10.1164/ajrccm.163.7.2007033

Cited by 159 publications

(136 citation statements)

References 26 publications

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“…3,[21][22][23] The EA di signal may also vary intra-individually, depending on the stage of disease and the physiologic reserve of the respiratory system. 24 Thus, the evolution of the EA di signal can be used as a measure of the progression of the respiratory function and possibly help predict the success of weaning from mechanical ventilation.…”

Section: Interpretation Of the Diaphragm Signalmentioning

confidence: 99%

Neurally Adjusted Ventilatory Assist: A Ventilation Tool or a Ventilation Toy?

Verbrugghe

Jorens

2011

Respir Care

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Mechanical ventilation has, since its introduction into clinical practice, undergone a major evolution from controlled ventilation to various modes of assisted ventilation. Neurally adjusted ventilatory assist (NAVA) is the newest development. The implementation of NAVA requires the introduction of a catheter to measure the electrical activity of the diaphragm (EA di ). NAVA relies, opposite to conventional assisted ventilation modes, on the EA di to trigger the ventilator breath and to adjust the ventilatory assist to the neural drive. The amplitude of the ventilator assist is determined by the instantaneous EA di and the NAVA level set by the clinician. The NAVA level amplifies the EA di signal and determines instantaneous ventilator assist on a breath-to-breath basis. Experimental and clinical data suggest superior patient-ventilator synchrony with NAVA. Patient-ventilator asynchrony is present in 25% of mechanically ventilated patients in the intensive care unit and may contribute to patient discomfort, sleep fragmentation, higher use of sedation, development of delirium, ventilator-induced lung injury, prolonged mechanical ventilation, and ultimately mortality. With NAVA, the reliance on the EA di signal, together with an intact ventilatory drive and intact breathing reflexes, allows integration of the ventilator in the neuro-ventilatory coupling on a higher level than conventional ventilation modes. The simple monitoring of the EA di signal alone may provide the clinician with important information to guide ventilator management, especially during the weaning process. Although, until now, little evidence proves the superiority of NAVA on clinically relevant end points, it seems evident that patient populations (eg, COPD and small children) with major patient-ventilator asynchrony may benefit from this new ventilatory tool.

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Section: Interpretation Of the Diaphragm Signalmentioning

confidence: 99%

Neurally Adjusted Ventilatory Assist: A Ventilation Tool or a Ventilation Toy?

Verbrugghe

Jorens

2011

Respir Care

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“…Although the diaphragm is at a mechanical disadvantage at higher lung volumes, the EAdi signal is not decreased. In fact, the response to weakened me-chanical output of the diaphragm is an increase in EAdi (12)(13)(14). With respect to cycling-off the ventilator breath, the neural expiration is not detected during PSV, which could lead to overinflation and excessive volume delivery, whereas with NAVA, cycling-off occurs when the diaphragm activity is turned off by the respiratory centers and hence should provide a more physiologic termination of the assist.…”

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confidence: 99%

Improved Synchrony and Respiratory Unloading by Neurally Adjusted Ventilatory Assist (NAVA) in Lung-Injured Rabbits

et al. 2007

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With increasing pressure support ventilation (PSV), a form of pneumatically triggered ventilation, there can be an increase in wasted inspiratory efforts (neural inspiratory efforts that fail to trigger the ventilator). With neurally adjusted ventilatory assist (NAVA), a mode of ventilation controlled by the electrical activity of the diaphragm (EAdi), synchrony should be maintained at high levels of assist. The aim of this study was to evaluate the response to increasing levels of PSV and NAVA on synchrony and diaphragm unloading in lung-injured rabbits. Animals were ventilated on PSV or NAVA in random order, each at three levels. We measured neural and ventilator respiratory rates, EAdi, transdiaphragmatic pressure (Pdi), and tidal volume (VT). At low PSV, 95% of neural efforts were triggered, compared with high PSV, where only 66% of the neural efforts were triggered. During NAVA, all neural efforts were triggered, regardless of level. Increasing NAVA levels reduced EAdi and Pdi-time products by 48% (p Ͻ 0.05) and 66% (p Ͻ 0.05). In contrast, increasing PSV did not reduce the diaphragm electrical activity-time product and increased the transdiaphragmatic pressuretime product (p Ͻ 0.05) due to the increased wasted efforts. We conclude that synchrony with the ventilator is an important determinant for diaphragm unloading. (Pediatr Res 61: 289-294, 2007) P atient-triggered ventilation in the pediatric intensive care unit setting is common (1) and compared with conventional mechanical ventilation has been shown to improve VT (2), work of breathing (2), and oxygenation (3) and to reduce blood pressure fluctuations (4) and transpulmonary pressure (5) in newborns. Despite these findings, a recent meta-analysis indicates that patient-triggered ventilation has no impact on mortality (6). One possible explanation for this may be that even though patient-triggered ventilation was used, synchronous ventilation may not have actually been achieved, an observation not reported in many trials.A common form of patient-triggered ventilation is PSV, a mode of partial ventilatory assist that is triggered by pressure or flow, is pressure targeted, and flow cycled. It is generally believed that increasing the level of assist with PSV unloads the respiratory muscles (7,8). However, investigators have demonstrated there may be a significant amount of respiratory work to trigger the ventilator (9), and there may be wasted inspiratory efforts, where the patient makes an inspiratory effort, but the ventilator fails to trigger. These asynchronies are aggravated at higher levels of assist (9,10) and possibly at higher respiratory rates because expiratory time is too short to allow complete exhalation. Dynamic hyperinflation puts the diaphragm at a mechanical disadvantage, thereby affecting the ability to trigger the ventilator.NAVA is a mode of partial ventilatory assist in which the ventilator is controlled by the electrical activity of the diaphragm (EAdi) (11). The EAdi represents the final neural output of the respiratory c...

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“…Patients with COPD or neonates cannot create enough inspiratory flow or airway pressure drop, and patient-ventilator asynchrony is common. 3,4 NAVA mode improves patientventilator synchrony in patients with COPD and neonates; however, it has not been reported to improve patient-ventilatory synchrony in patients with unstable E di .…”

Section: Discussionmentioning

confidence: 96%

Neurally Adjusted Ventilatory Assist Improves Patient-Ventilator Synchrony in a Patient With Tetanus and Unstable Diaphragmatic Electrical Activity

et al. 2015

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A 79-y-old man with generalized tetanus was admitted to the ICU. A left-forearm wound was surgically debrided, and the wound was closed. On postoperative day 1, after the patient experienced opisthotonos and convulsions, endotracheal intubation was performed. Propofol and diazepam were infused but failed to stop the convulsions. Morphine, midazolam, dantrolene, and rocuronium were used to ameliorate the muscle spasms. Magnesium sulfate was also infused. On postoperative day 15, patient-ventilator asynchrony was apparent. The patient showed recurrent tachypnea and bradypnea, which seemed typical of Cheyne-Stokes respiration. A neurally adjusted ventilatory assist (NAVA) catheter was inserted transnasally, and electrical activity of the diaphragm (E di ) was monitored. Readings showed regular attempts to breathe at 40 -50 breaths/min with periodic changes in E di amplitude. NAVA mode improved patient-ventilator synchrony. Periodic breathing continued for 2 weeks. We stopped monitoring E di on postoperative day 39. He began respiratory rehabilitation and was transferred to a hospital for rehabilitation on postoperative day 80. We encountered periodic respiration in a patient with tetanus. E di monitoring revealed periodic amplitude change. The cause of the periodic breathing pattern in this patient could not be determined but may be attributable to side effects of the pharmacologic interventions or the natural history of the disease itself. NAVA mode improved patient-ventilator synchrony.

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Diaphragm Activation during Exercise in Chronic Obstructive Pulmonary Disease

Cited by 159 publications

References 26 publications

Neurally Adjusted Ventilatory Assist: A Ventilation Tool or a Ventilation Toy?

Neurally Adjusted Ventilatory Assist: A Ventilation Tool or a Ventilation Toy?

Improved Synchrony and Respiratory Unloading by Neurally Adjusted Ventilatory Assist (NAVA) in Lung-Injured Rabbits

Neurally Adjusted Ventilatory Assist Improves Patient-Ventilator Synchrony in a Patient With Tetanus and Unstable Diaphragmatic Electrical Activity

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