• Roberto Brito, MoraisCaio C ACCADivisão de Pneumologia, Instituto Do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.Divisão de Fisioterapia, Hospital das Clínicas da Universidade Federal de Pernambuco, Recife, Brazil., Daniel H Arellano, Abraham I J Gajardo, Alejandro Bruhn, Laurent J Brochard, AmatoMarcelo B PMBPDivisão de Pneumologia, Instituto Do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil., and Rodrigo A Cornejo.
• Departamento de Medicina, Hospital Clínico Universidad de Chile, Unidad de Pacientes Críticos, Dr. Carlos Lorca Tobar 999, Independencia, Santiago, Chile.
• Crit Care. 2025 Jan 10; 29 (1): 1919.

BackgroundDouble cycling with breath-stacking (DC/BS) during controlled mechanical ventilation is considered potentially injurious, reflecting a high respiratory drive. During partial ventilatory support, its occurrence might be attributable to physiological variability of breathing patterns, reflecting the response of the mode without carrying specific risks.MethodsThis secondary analysis of a crossover study evaluated DC/BS events in hypoxemic patients resuming spontaneous breathing in cross-over under neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV +), and pressure support ventilation (PSV). DC/BS was defined as two inspiratory cycles with incomplete exhalation. Measurements included electrical impedance signal, airway pressure, esophageal and gastric pressures, and flow. Breathing variability, dynamic compliance (CLdyn), and end-expiratory lung impedance (EELI) were analyzed.ResultsTwenty patients under assisted breathing, with a median of 9 [5-14] days on mechanical ventilation, were included. DC/BS was attributed to either a single (42%) or two apparent consecutive inspiratory efforts (58%). The median [IQR] incidence of DC/BS was low: 0.6 [0.1-2.6] % in NAVA, 0.0 [0.0-0.4] % in PAV + , and 0.1 [0.0-0.4] % in PSV (p = 0.06). DC/BS events were associated with patient's coefficient of variability for tidal volume (p = 0.014) and respiratory rate (p = 0.011). DC/BS breaths exhibited higher tidal volume, muscular pressure and regional stretch compared to regular breaths. Post-DC/BS cycles frequently exhibited improved EELI and CLdyn, with no evidence of expiratory muscle activation in 63% of cases.ConclusionsDC/BS events during partial ventilatory support were infrequent and linked to breathing variability. Their frequency and physiological effects on lung compliance and EELI resemble spontaneous sighs and may not be considered a priori as harmful.© 2025. The Author(s).

20 keywords...

hide…