Tidal Volume Estimation during Helmet Noninvasive Ventilation: an Experimental Feasibility Study

• Published in: Scientific reports Vol. 9; no. 1; pp. 17324 - 8
• Main Authors: Cortegiani, Andrea, Navalesi, Paolo, Accurso, Giuseppe, Sabella, Ignazio, Misseri, Giovanni, Ippolito, Mariachiara, Bruni, Andrea, Garofalo, Eugenio, Palmeri, Cesira, Gregoretti, Cesare
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.11.2019; Nature Publishing Group
• Subjects: 692/308/2778; 692/700/565; Adult; Bias; Equipment Design; Feasibility Studies; Female; Head Protective Devices; Healthy Volunteers; Humanities and Social Sciences; Humans; Male; Manikins; Mechanical ventilation; multidisciplinary; Noninvasive Ventilation - instrumentation; Noninvasive Ventilation - methods; Positive-Pressure Respiration - instrumentation; Positive-Pressure Respiration - methods; Pressure; Protective equipment; Reproducibility of Results; Respiratory Mechanics - physiology; Science; Science (multidisciplinary); Tidal Volume - physiology; Turbines; Ventilation; Ventilators, Mechanical
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-54020-5

We performed a bench (BS) and human (HS) study to test the hypothesis that estimation of tidal volume (V T ) during noninvasive helmet pressure support ventilation (nHPSV) would be possible using a turbine driven ventilator (TDV) coupled with an intentional leak single-limb vented circuit. During the BS a mannequin was connected to a lung simulator (LS) and at different conditions of respiratory mechanics, positive end expiratory pressure (PEEP) levels and leaks (30, 50 and 80 L/min). All differences were within the 95% limits of agreement (LoA) in all conditions in the Bland-Altman plot. The overall bias (difference between V T measured by TDV and LS) was 35 ml (95% LoA 10 to 57 ml), 15 ml (95% LoA −40 to 70 ml), 141 ml (95% LoA 109 to 173 ml) in the normal, restrictive and obstructive conditions. The bias at different leaks flow in normal condition was 29 ml (95% LoA 19 to 38 ml). In the HS four healthy volunteers using nHPSV had a pneumotachograph (P) inserted through a mouthpiece to measure subject’s V T .The bias showed a scarce clinical relevance. In conclusions, V T estimation seems to be feasible and accurate in all conditions but the obstructive one. Additional leaks seem not to affect V T reliability.