Time Course of Expiratory Flow Limitation in COPD Patients During Acute Respiratory Failure Requiring Mechanical Ventilation

Abstract Background Tidal expiratory flow limitation (EFLT) promotes intrinsic PEEP (PEEPi) in patients with chronic obstructive pulmonary disease (COPD). Applying non-invasive ventilation (NIV) with an expiratory positive airway pressure (EPAP) matching PEEPi improves gas exchange, reduces work of breathing and ineffective efforts. We aimed to evaluate the effects of a novel NIV mode that continuously adjusts EPAP to the minimum level that abolishes EFLT. Methods This prospective, cross-over, open-label study randomized patients to one night of fixed-EPAP and one night of EFLT-abolishing-EPAP. The primary outcome was transcutaneous carbon dioxide pressure (PtcCO2). Secondary outcomes were: peripheral oxygen saturation (SpO2), frequency of ineffective efforts, breathing patterns and oscillatory mechanics. Results We screened 36 patients and included 12 in the analysis (age 72 ± 8 years, FEV1 38 ± 14%Pred). The median EPAP did not differ between the EFLT-abolishing-EPAP and the fixed-EPAP night (median (IQR) = 7.0 (6.0, 8.8) cmH2O during night vs 7.5 (6.5, 10.5) cmH2O, p = 0.365). We found no differences in mean PtcCO2 (44.9 (41.6, 57.2) mmHg vs 54.5 (51.1, 59.0), p = 0.365), the percentage of night time with PtcCO2 > 45 mm Hg was lower (62(8,100)% vs 98(94,100)%, p = 0.031) and ineffective efforts were fewer (126(93,205) vs 261(205,351) events/hour, p = 0.003) during the EFLT-abolishing-EPAP than during the fixed-EPAP night. We found no differences in oxygen saturation and lung mechanics between nights. Conclusion An adaptive ventilation mode targeted to abolish EFLT has the potential to reduce hypercapnia and ineffective efforts in stable COPD patients receiving nocturnal NIV. Trial registration: ClicalTrials.gov, NCT04497090. Registered 29 July 2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04497090.

Download Full-text

Lung and chest wall mechanics in patients with acute respiratory distress syndrome, expiratory flow limitation, and airway closure

Journal of Applied Physiology ◽

10.1152/japplphysiol.00059.2020 ◽

2020 ◽

Vol 128 (6) ◽

pp. 1594-1603 ◽

Cited By ~ 2

Author(s):

Claude Guérin ◽

Nicolas Terzi ◽

Louis-Marie Galerneau ◽

Mehdi Mezidi ◽

Hodane Yonis ◽

...

Keyword(s):

Mechanical Ventilation ◽

Distress Syndrome ◽

Flow Limitation ◽

Airway Closure ◽

Positive End Expiratory Pressure ◽

Expiratory Flow Limitation ◽

Lung Elastance ◽

Chest Wall Mechanics ◽

Expiratory Flow ◽

Better Than

Expiratory flow limitation (EFL) and airway closure (AC) were observed in 32% and 52%, respectively, of 25 patients with ARDS investigated during mechanical ventilation in supine position with a positive end-expiratory pressure of 5 cmH2O. The performance of dynamic lung elastance to detect expiratory flow limitation was good and better than that to detect airway closure. The vast majority of patients with EFL also had AC; however, AC can occur in the absence of EFL.

Download Full-text

Exacerbation History In COPD Patients With And Without Expiratory Flow Limitation (EFL)

10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a3739 ◽

2012 ◽

Author(s):

Bernt B. Aarli ◽

Peter M. Calverley ◽

Per Bakke ◽

Tomas M.L. Eagan ◽

Jon A. Hardie

Keyword(s):

Flow Limitation ◽

Expiratory Flow Limitation ◽

Copd Patients ◽

Expiratory Flow

Download Full-text

Expiratory flow limitation in intensive care: prevalence and risk factors

Critical Care ◽

10.1186/s13054-019-2682-4 ◽

2019 ◽

Vol 23 (1) ◽

Cited By ~ 7

Author(s):

Carlo Alberto Volta ◽

Francesca Dalla Corte ◽

Riccardo Ragazzi ◽

Elisabetta Marangoni ◽

Alberto Fogagnolo ◽

...

Keyword(s):

Risk Factors ◽

Mechanical Ventilation ◽

Intensive Care ◽

Fluid Balance ◽

Adverse Outcomes ◽

Small Airways ◽

Flow Limitation ◽

Expiratory Flow Limitation ◽

Expected Length ◽

Expiratory Flow

Abstract Background Expiratory flow limitation (EFL) is characterised by a markedly reduced expiratory flow insensitive to the expiratory driving pressure. The presence of EFL can influence the respiratory and cardiovascular function and damage the small airways; its occurrence has been demonstrated in different diseases, such as COPD, asthma, obesity, cardiac failure, ARDS, and cystic fibrosis. Our aim was to evaluate the prevalence of EFL in patients requiring mechanical ventilation for acute respiratory failure and to determine the main clinical characteristics, the risk factors and clinical outcome associated with the presence of EFL. Methods Patients admitted to the intensive care unit (ICU) with an expected length of mechanical ventilation of 72 h were enrolled in this prospective, observational study. Patients were evaluated, within 24 h from ICU admission and for at least 72 h, in terms of respiratory mechanics, presence of EFL through the PEEP test, daily fluid balance and followed for outcome measurements. Results Among the 121 patients enrolled, 37 (31%) exhibited EFL upon admission. Flow-limited patients had higher BMI, history of pulmonary or heart disease, worse respiratory dyspnoea score, higher intrinsic positive end-expiratory pressure, flow and additional resistance. Over the course of the initial 72 h of mechanical ventilation, additional 21 patients (17%) developed EFL. New onset EFL was associated with a more positive cumulative fluid balance at day 3 (103.3 ml/kg) compared to that of patients without EFL (65.8 ml/kg). Flow-limited patients had longer duration of mechanical ventilation, longer ICU length of stay and higher in-ICU mortality. Conclusions EFL is common among ICU patients and correlates with adverse outcomes. The major determinant for developing EFL in patients during the first 3 days of their ICU stay is a positive fluid balance. Further studies are needed to assess if a restrictive fluid therapy might be associated with a lower incidence of EFL.

Download Full-text

Tidal expiratory flow limitation induces expiratory looping of the alveolar pressure-flow relation in COPD patients

Journal of Applied Physiology ◽

10.1152/japplphysiol.00664.2019 ◽

2020 ◽

Vol 129 (1) ◽

pp. 75-83

Author(s):

Matteo Pecchiari ◽

Dejan Radovanovic ◽

Camilla Zilianti ◽

Laura Saderi ◽

Giovanni Sotgiu ◽

...

Keyword(s):

Chronic Obstructive Pulmonary Disease ◽

Pulmonary Disease ◽

Chronic Obstructive ◽

Flow Limitation ◽

Alveolar Pressure ◽

Expiratory Flow Limitation ◽

Obstructive Pulmonary Disease ◽

Copd Patients ◽

Expiratory Flow ◽

Spontaneously Breathing

In stable chronic obstructive pulmonary disease (COPD) patients spontaneously breathing at rest, tidal expiratory flow limitation is the major determinant of the occurrence of expiratory looping in the plethysmographic flow-alveolar pressure diagram. In these patients the magnitude and the characteristics of the loop can be used as predictors of the presence of tidal expiratory flow limitation.

Download Full-text