Background: In mechanically ventilated patients with COPD, the response of the expiratory resistance of the respiratory system (expiratory R(RS)) to bronchodilators is virtually unknown.

Objective: To examine the effect of inhaled albuterol on expiratory R(RS), and the correlation of albuterol-induced changes in expiratory R(RS) with end-inspiratory resistance and the expiratory flow-volume relationship.

Methods: We studied 10 mechanically ventilated patients with COPD exacerbation, before and 30 min after administration of albuterol. We obtained flow-volume curves during passive expiration, divided the expired volume into 5 equal volume slices, and then calculated the time constant and dynamic effective deflation compliance of the respiratory system (effective deflation C(RS)) of each slice via regression analysis of the volume-flow and post-occlusion volume-tracheal pressure relationships, respectively. For each slice we calculated expiratory R(RS) as the time constant divided by the effective deflation C(RS).

Results: Albuterol significantly decreased the expiratory R(RS) (mean expiratory R(RS) 42.68 ± 17.8 cm H(2)O/L/s vs 38.08 ± 16.1 cm H(2)O/L/s) and increased the rate of lung emptying toward the end of expiration (mean time constant 2.51 ± 1.2 s vs 2.21 ± 1.2 s). No correlation was found between the albuterol-induced changes in expiratory R(RS) and that of end-inspiratory resistance. Only at the end of expiration did albuterol-induced changes in the expiratory flow-volume relationship correlate with changes in expiratory R(RS) in all patients.

Conclusions: In patients with COPD, albuterol significantly decreases expiratory resistance at the end of expiration. In mechanically ventilated patients, neither inspiratory resistance nor the whole expiratory flow-volume curve may be used to evaluate the bronchodilator response of expiratory resistance.

Download full-text PDF

Source
http://dx.doi.org/10.4187/respcare.00984DOI Listing

Publication Analysis

Top Keywords

expiratory rrs
32
expiratory resistance
16
mechanically ventilated
16
ventilated patients
16
changes expiratory
16
expiratory
14
patients copd
12
albuterol-induced changes
12
expiratory flow-volume
12
time constant
12

Similar Publications

Article Synopsis
  • APRV (Airway Pressure Release Ventilation) may help protect against lung damage from atelectrauma by limiting the duration of expirations, preventing harmful separation of epithelial surfaces during breathing.
  • A study using a porcine model of ARDS tested different levels of inspiratory pressure and expiration timing to analyze the effects on lung mechanics and resistance post-injury.
  • Results indicated that shorter expirations reduced lung strain during inspiration, suggesting that optimal timing in APRV can enhance lung function recovery after injury.
View Article and Find Full Text PDF

Background: The clinical effectiveness of hypertonic saline (HS) in individuals with cystic fibrosis (CF) can be compromised by adverse effects. The objective of this study was to examine the efficacy of hyaluronic acid (HA) in mitigating these negative occurrences.

Methods: A comprehensive review of the literature was carried out using three electronic databases: Medline, Cochrane Central, and Embase.

View Article and Find Full Text PDF

Background: Whether individualized positive end-expiratory pressure (PEEP) improves intraoperative oxygenation and reduces postoperative pulmonary complications (PPCs) remains unclear. This systematic review and meta-analysis examined whether individualized PEEP is associated with improved intraoperative oxygenation and reduce PPCs for patients needing pneumoperitoneum with the Trendelenburg position during surgery.

Methods: Medline, Embase, the Cochrane Library, and www.

View Article and Find Full Text PDF
Article Synopsis
  • The study aimed to compare lung function in healthy horses and those with mild-moderate equine asthma (MEA) using a method called oscillometry.
  • Thirty-seven horses were divided into two groups: healthy and MEA-affected, with diagnoses confirmed through various medical tests.
  • Results revealed that while no significant differences were found in overall resistance and reactance between the groups, specific frequency dependence measures did differ, indicating a potential new diagnostic parameter for detecting MEA.
View Article and Find Full Text PDF

Background: Prior studies have reported inconsistent results regarding the association between driving pressure-guided ventilation and postoperative pulmonary complications (PPCs). We aimed to investigate whether driving pressure-guided ventilation is associated with a lower risk of PPCs.

Methods: We systematically searched electronic databases for RCTs comparing driving pressure-guided ventilation with conventional protective ventilation in adult surgical patients.

View Article and Find Full Text PDF

Want 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!