Mechanically ventilated patients exhibit decreased particle flow in exhaled breath as compared to normal breathing patients

Abstract

IntroductionIn this cohort study, we evaluated whether the particles in exhaled air (PExA) device can be used in conjunction with mechanical ventilation during surgery. The PExA device consists of an optical particle counter and an impactor that collects particles in exhaled air. Our aim was to establish the feasibility of the PExA device in combination with mechanical ventilation (MV) during surgery and if collected particles could be analysed. Patients with and without nonsmall cell lung cancer (NSCLC) undergoing lung surgery were compared to normal breathing (NB) patients with NSCLC.MethodsA total of 32 patients were included, 17 patients with NSCLC (MV-NSCLC), nine patients without NSCLC (MV-C) and six patients with NSCLC and not intubated (NB). The PEx samples were analysed for the most common phospholipids in surfactant using liquid-chromatography-mass-spectrometry (LCMS).ResultsMV-NSCLC and MV-C had significantly lower numbers of particles exhaled per minute (particle flow rate; PFR) compared to NB. MV-NSCLC and MV-C also had a siginificantly lower amount of phospholipids in PEx when compared to NB. MV-NSCLC had a significantly lower amount of surfactant A compared to NB.ConclusionWe have established the feasibility of the PExA device. Particles could be collected and analysed. We observed lower PFR from MV compared to NB. High PFR during MV may be due to more frequent opening and closing of the airways, known to be harmful to the lung. Online use of the PExA device might be used to monitor and personalise settings for mechanical ventilation to lower the risk of lung damage.

Particle flow rate from the airways as fingerprint diagnostics in mechanical ventilation in the intensive care unit: a randomised controlled study

“…This study reiterates the finding that measurement of PFR using the PExA device is safe in conjunction with mechanical ventilation [ 18 , 19 , 21 ]. This was concluded as there were no signs of significant air leakage, haemodynamic impact or increased peak pressures which could be harmful to the patients.…”

“…Our hypothesis regarding high PFR during PSV ventilation follows that while initiating their own breath in this mode, patients use a breathing pattern similar to that of spontaneously breathing patients. As seen in a previous study, PFR in spontaneously breathing patients is significantly higher than that found in patients placed on mechanical ventilation [ 21 ]. The use of the diaphragm, as in spontaneous breathing, promotes the opening and closing of the distal airways and may thus influence the production of EBPs [ 12 ].…”

“…As seen in a previous study, PFR in spontaneously breathing patients is significantly higher than that found in patients placed on mechanical ventilation (21). The use of the diaphragm, as in spontaneous breathing, promotes the opening and closing of the distal airways and may thus influence the production of EBPs (12).…”

Different particle flow from exhaled air after gradual increase of PEEP during mechanical ventilation

“…A previous study with the Pexa technique showed that different tidal volumes and different PEEP resulted in different particle count from the airways in vivo, post mortem and during ex vivo lung perfusion [8]. In another study performed in the operating theatre showed that patients on mechanical ventilation with the use of PEEP compared to normal breathing patients display a lower particle count [14]. These ndings indicate that an open airway during mechanical ventilation generates lower levels of particles compared to an airway that repeatedly collapses and reopens.…”

Small droplet emission in exhaled breath during different breathing manoeuvres: Implications for clinical lung function testing during COVID‐19

“…We reanalysed data from healthy volunteers (mean (SD) age 46(17) years, body mass index 23.9 (2.9) kg/m 2 , FEV 1 101.8(11.0) % predicted) using both previously published and unpublished data. 7,8 Studies were approved by the Ethical Review Board at the University of Gothenburg. For measures in confirmed airways disease, such as asthma and COPD, these data suggest that fewer droplets would be produced, potentially reducing risk, if a FEV manoeuvre was stopped once achieved and before exhalation to RV.…”