Background: We hypothesized that the lack of benefit of setting a low versus a high PEEP in patients with ARDS may be due in part to differences in the dynamic behavior of the expiratory valve in ventilators. We tested this hypothesis by conducting a bench comparison of the dynamic behavior of expiratory valves on ICU ventilators currently in use.
Methods: We attached 7 ICU ventilators (C5, C6, Carescape, PB980, ServoU, V500, and V680) to the ASL 5000 lung model (passive condition with compliance 20 mL/cm HO and resistance 5 cm HO/L/s) and set in volume controlled mode (tidal volume 0.8 L, breathing frequency 10 breaths/min). Flow and pressure were measured just before the exhalation valve. At PEEP of 5, 10, and 15 cm HO, the median instantaneous expiratory resistance, the time to valve opening, and the pressure time products above or below the values of PEEP (expressed in cm HO × s) were determined.
Results: Median instantaneous expiratory resistance values differed between the ventilators and PEEP settings with a significant interaction: at PEEP 5 cm HO, the median (interquartile range) expiratory resistance values were 3.9 (3.5-4.7), 3.0 (3.0-3.1), 20.9 (15.8-24.9), 27.4 (26.5-43.2), 13.8 (13.6-13.9), 4.4 (4.0-4.6), and 34.3 (33.7-33.8) cm HO/L/s, for the C5, C6, Carescape, PB980, ServoU, V500, and V680, respectively. For all the PEEP settings, the corresponding times to valve opening were 0.080 (0.077-0.082), 0.082 (0.080-0.085), 0.110 (0.105-0.110), 0.100 (0.085-1.05), 0.072 (0.062-0.072), 0.145 (0.115-0.150), and 0.075 (0.070-0.080) s, respectively, and pressure-time products were 2.8 (2.1-7.4), 6.8 (6.7-7.3), 2.4 (2.1-2.4), 3.5 (2.7-3.6), 1.8 (1.8-2.1), 2.8 (2.7-2.9), and 5.7 (5.4-5.9) cm HO × s, respectively.
Conclusions: The resistance of active expiratory valves differed significantly between the 7 ICU ventilators tested.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.4187/respcare.08098 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Effect of Treatment With Balanced Crystalloids Versus Normal Saline on the Mortality of Critically Ill Patients With and Without Traumatic Brain Injury: A Systematic Review and Meta-Analysis.
Anesth Analg
January 2025
School of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain.
Background: Some studies suggest that balanced solutions may improve outcomes in critical care patients. However, in patients with traumatic brain injury (TBI) existing data indicate that normal saline may be preferred. We hypothesized that mortality in critically ill patients with and without TBI would differ with the use of balanced salt solutions versus normal saline.
View Article and Find Full Text PDFPsychological symptoms, quality of life and dyadic relations in family members of intensive care survivors: a multicentre, prospective longitudinal cohort study.
Ann Intensive Care
January 2025
School of Medicine and Psychology, Australian National University, Canberra, Australia.
Background: There is scarce literature evaluating long term psychological or Quality of Life (QoL) outcomes in family members of ICU survivors, who have not experienced invasive ventilation. The objective was to compare long-term psychological symptoms and QoL outcomes in family members of intubated versus non-intubated ICU survivors and to evaluate dyadic relationships between paired family members and survivors.
Methods: Prospective, multicentre cohort study among four medical-surgical ICUs in Australia.
Assessing fluid responsiveness by using functional hemodynamic tests in critically ill patients: a narrative review and a profile-based clinical guide.
J Clin Monit Comput
January 2025
IRCCS Humanitas Research Hospital, via Manzoni 56, Rozzano - Milan, 20089, Italy.
Fluids are given with the purpose of increasing cardiac output (CO), but approximately only 50% of critically ill patients are fluid responders. Since the effect of a fluid bolus is time-sensitive, it diminuish within few hours, following the initial fluid resuscitation. Several functional hemodynamic tests (FHTs), consisting of maneuvers affecting heart-lung interactions, have been conceived to discriminate fluid responders from non-responders.
View Article and Find Full Text PDFMediating Role of Platelet Count Increase in Unfractionated Heparin Treatment for Sepsis Patients: A Retrospective Cohort Analysis.
Br J Hosp Med (Lond)
December 2024
Department of Critical Care Medicine, Peking University People's Hospital, Beijing, China.
The role of heparin in sepsis therapy has been widely debated. The controversy surrounding heparin's use as an anticoagulant in sepsis may stem from differences in sepsis definitions, study designs, timing and dosage of drug administration, treatment duration, complications, and patient severity. In this study, we aimed to determine the optimal timing and dosage of heparin in patients with sepsis, identify specific subgroups that could benefit from heparin therapy, and explore laboratory markers to assess its efficacy.
View Article and Find Full Text PDFEfficacy of early enteral feeding with supplemented mother's milk on postoperative outcomes of cardiac surgical infants: A randomized controlled trial.
Ann Pediatr Cardiol
December 2024
Department of Biostatistics, AIIMS, New Delhi, India.
Introduction: Congenital heart disease (CHD)-associated malnutrition is a systemic consequence of CHD. Dietary recommendations to fulfill nutritional requirements are lacking. This randomized controlled trial (RCT) was conducted to determine the efficacy of early enteral feeding with supplemented expressed breast milk (suppl-EBM) versus expressed breast milk (EBM) in improving the weight of postoperative cardiac surgical infants.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!