Effects of Trigger Algorithms on Trigger Performance and Patient-Ventilator Synchrony

• Published in: Respiratory care Vol. 70; no. 10; p. 1285
• Main Authors: Morinishi, Keisuke, Itagaki, Taiga, Akimoto, Yusuke, Chikata, Yusuke, Oto, Jun
• Format: Journal Article
• Language: English
• Published: United States 01.10.2025
• Subjects: Algorithms; Humans; Positive-Pressure Respiration - methods; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary Disease, Chronic Obstructive - therapy; Respiration, Artificial - methods; Respiratory Distress Syndrome - physiopathology; Respiratory Distress Syndrome - therapy; Respiratory Mechanics - physiology; Tidal Volume; patient–ventilator asynchrony; trigger algorithm; mechanical ventilation; flow waveform analysis
• ISSN: 1943-3654
• DOI: 10.1089/respcare.12694

Patient-ventilator synchrony is essential for successful patient-triggered ventilation. This study compared the ability of a trigger algorithm, based on detailed analysis of flow changes (IntelliSync+, Hamilton Medical), to trigger patient breaths with conventional algorithms. Three models with different lung mechanics (normal, ARDS, and COPD) at 3 severities were simulated with a lung model ventilated in pressure control continuous mandatory ventilation or pressure control continuous spontaneous ventilation (PC-CSV). Inspiratory pressure above PEEP was set at 15 cm H O and PEEP at 5 cm H O. Inspiratory trigger was selected from IntelliSync+ (IS+insp), flow trigger (1- 5 L/min), or pressure trigger (-1 to -5 cm H O). In PC-CSV, expiratory trigger was set at IntelliSync+ (IS+exp) or cycling criteria (5%, 25%, and 40% for ARDS, normal, and COPD, respectively). Measurements were performed with and without leak (50% inspiratory tidal volume). Five breaths per condition were collected to calculate trigger delay time and asynchronous events. For pressure trigger, none of the conditions resulted in 3 successfully triggered consecutive breaths. Overall trigger delay time was significantly longer with flow trigger than with IS+insp in normal (99 vs 81 ms without leak, < .001; 98 vs 80 ms with leak, < .001) and ARDS models (334 vs 223 ms without leak, < .001; 320 vs 236 ms with leak, = .02). Across all conditions, ineffective efforts occurred more frequently with flow trigger than with IS+insp (7.3% vs 1.5% without leak, = .01; 10.8% vs 3.0% with leak, = .01). In PC-CSV, overall cycling delay time with IS+exp was equivalent or longer compared with cycling criteria. In this lung model study, IS+insp demonstrated similar trigger time and fewer ineffective efforts compared with flow trigger even in simulated respiratory conditions, whereas cycling delay time was unaffected by IS+exp because of large variations between conditions.