Chest
Laboratory and Animal InvestigationsPhysiologic Evaluation of Different Levels of Assistance During Noninvasive Ventilation Delivered Through a Helmet
Section snippets
Materials and Methods
The protocol was approved by our institutional review board, and written informed consent was obtained from each subject. NIV was delivered through a helmet equipped with an soft inner inflatable cushion for dead space reduction (CaStar Starmed; Starmed; Mirandola, Italy) [Fig 1]using an ICU ventilator (EVITA 4; Dräger Medical; Lübeck, Germany) set in PS ventilation (PSV) mode. The fraction of inspired oxygen was set at 0.21, and the inspiratory trigger threshold was set at 2 L/min, checking
Results
All the subjects completed the study protocol. In comparison to spontaneous breathing, during helmet NIV, RRpes was reduced by 7% during PS/PEEP at 5/5 cm H2 O (p = 0.086), by 13.1% during PS/PEEP at 10/5 cm H2 O (both with and without an inflated cushion) [p = 0.023 and p = 0.015, respectively], by 28% during PS/PEEP at 15/5 cm H2 O (p = 0.000003),and by 5.2% during PS/PEEP at 10/10 cm H2 O (p = 0.12) [Table 1].
No significant differences were found between RRvent and RRpes, which were similar
Discussion
The main finding of the present study is that increasing levels of assistance in healthy volunteers receiving PS ventilation through a helmet significantly reduced RRpes, with a significant increase in Vt. Increasing levels of assistance produced a significant reduction in tidal excursions of Pes only during PS/PEEP at 10/5 cm H2 O with the cushion inflated and PS/PEEP at 10/10 cm H2 O, while, compared to spontaneous breathing, ventilatory support produced a significant decrease of PTP per
ACKNOWLEDGMENT
The authors thank Dr. Melanie Lindsey for her helpful review of the manuscript.
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Non-invasive ventilation for acute hypoxemic respiratory failure, including COVID-19
2023, Journal of Intensive MedicineCitation Excerpt :To limit this phenomenon, higher gas flows are necessary.[80] Despite the use of optimal settings, asynchronies often occur during helmet ventilation; however, they usually do not affect its performance[70,81] and may even exert a protective function since pressurization delay at inspiration causes uncoupling between the pleural pressure (patient effort) and airway pressure (pressure support), thus reducing positive transpulmonary pressure swings. Delays in expiratory cycling increase end-expiratory pressure, contributing to increase alveolar recruitment.[29]
Noninvasive Options
2018, Critical Care ClinicsCitation Excerpt :Compared with CPAP, helmet-delivered NIV in pressure support ventilation (PSV) mode can provide a more efficient CO2 washout, probably because of the phasic administration of inspiratory flow during such a ventilatory mode.15 In addition, the analysis of CO2 rebreathing during helmet-delivered PSV does not show any significant reduction in inspired CO2 after increasing the level of inspiratory assistance.15 Using a sophisticated computational fluid dynamic model to evaluate the effective dead space between different NIV interfaces, Fodil and colleagues16 showed that the dead space differed only modestly (110–370 mL) between the face mask and the helmet, whereas their internal volumes were markedly different (110–10,000 mL).
Noninvasive Ventilation in Critically Ill Patients
2015, Critical Care ClinicsCitation Excerpt :Helmet interfaces were originally used to deliver a precise oxygen concentration during hyperbaric oxygen therapy. The United States Food and Drug Administration has not approved any of the available helmets, but helmets have been approved in some other countries.41,64,72–87 When using a helmet with a CPAP generator, a minimum flow of 40 L/min is mandatory to avoid CO2 rebreathing.88,89
Monitoring the patient–ventilator asynchrony during non-invasive ventilation
2023, Frontiers in MedicineAdvantages and drawbacks of helmet noninvasive support in acute respiratory failure
2023, Expert Review of Respiratory Medicine
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
Presented in part as abstract at the Sixteenth Annual ESICM Congress, Amsterdam, October 2003.
Funded by a research grant from Università Cattolica del Sacro Cuore, No. D1-PT 0004162.