Relation between peak and integral of the diaphragm electromyographic activity at different levels of support during weaning from mechanical ventilation: A physiologic study

• Published in: Journal of critical care 2015-02, Vol.30 (1), p.7-12
• Main Authors: Muttini, Stefano, MD, Villani, Pier Giorgio, MD, Trimarco, Roberta, MD, Bellani, Giacomo, MD, Grasselli, Giacomo, MD, Patroniti, Nicolò, MD
• Format: Article
• Language: English
• Subjects: Aged; Area Under Curve; Catheters; Critical Care; Diaphragm - physiology; Diaphragmatic electrical activity; Electromyography; Female; Humans; Intensive care; Male; Middle Aged; Mortality; Neutrally adjusted ventilator assist; Patients; Physiology; Prospective Studies; Respiration, Artificial - methods; Respiratory Insufficiency - physiopathology; Respiratory Insufficiency - therapy; Respiratory Rate - physiology; Respiratory therapy; Software; Success; Tidal Volume - physiology; Ventilation; Ventilator Weaning; Ventilators; Weaning
• ISSN: 0883-9441; 1557-8615
• DOI: 10.1016/j.jcrc.2014.08.013

Abstract Purpose To investigate the relationship between peak (EAdipeak ) and area under the curve (EAdiAUC ) of diaphragm electrical activity, and to evaluate the validity of their ratio (P/I index) as a measure of the imbalance between drive and sustainability of effort demand at different support levels. Materials Prospective physiological study on 18 ready-to-wean patients ventilated with neurally adjusted ventilatory assist (NAVA) undergoing 2 levels of NAVA (NAVA100% and NAVA50% ) followed by a weaning trial with continuous positive airway pressure, according to which patients were classified as success or failure. Tidal volume (VT ), respiratory rate, EAdipeak , EAdiAUC , rapid shallow breathing index (respiratory rate/VT ), neuroventilatory index (VT /EAdipeak ), and P/I index were obtained at the end of each step. Results The slopes of regression line between EAdipeak and EAdiAUC (a mathematical equivalent of P/I index) and P/I index were significantly higher in failures. At variance with other variables, P/I index did not vary with level of support. P/I index was inversely correlated with inspiratory time at all support levels. Conclusions The relationship between EAdipeak and EAdiAUC and the P/I index may give important information on the balance between respiratory drive and inspiratory demand sustainability.