Evaluation of nebulised acetylcysteine and normal saline in the treatment of sputum retention following thoracotomy.

Abstract

Background-The use of acetylcysteine as a mucolytic agent is controversial. In 1962 it was claimed to be "the most effective agent ... for the liquefaction of ... secretions" but was subsequently taken off the market as a respirator solution. Normal saline, on the other hand, is becoming increasingly popular. A study was undertaken to determine which solution is more effective at clearing retained secretions following thoracotomy. Methods-The study included 10 patients and was of single blind, two-way crossover design. Measurements taken before and after each treatment included sputum viscosity, difficulty of expectoration, weight of sputum expectorated, and oxygen saturation.Results -Following nebulisation of acetylcysteine, sputum viscosity was reduced, difficulty of expectoration was reduced, the weight of sputum expectorated was increased, and oxygen saturation was increased. There were no changes after nebulisation of normal saline. Conclusions -This study shows that, following thoracotomy, nebulised acetylcysteine reduces sputum viscosity, making expectoration easier and improving oxygenation. Nebulised normal saline has no effect. (Thorax 1996;51:429-432) Keywords: nebulised acetylcysteine, sputum viscosity, physiotherapyPostoperative pulmonary complications following abdominal and thoracic surgery are the most significant cause of morbidity and mortality in the postoperative period.' Thoracotomy results in reduced lung volumes, impaired gas exchange, and damaged respiratory defence mechanisms.2 Mucus secretion and viscosity are therefore increased and mucociliary clearance is decreased, leading to retention of secretions, atelectasis, infection, and hypoxaemia.34The use of nebulised mycolytic agents is one method of enhancing mucociliary clearance. Acetylcysteine has been shown to reduce mucus viscosity in vitro5 but this has not been demonstrated in vivo in the postoperative period. Nebulised normal saline has been shown to increase the clearance of secretions when included in a physiotherapy regimen for the treatment of patients with bronchiectasis.6 No studies of nebulised drugs have measured sputum viscosity in patients following thoracotomy. A controlled trial was therefore undertaken to compare the efficacy ofnebulised acetylcysteine and normal saline in the treatment of sputum retention following thoracotomy in order to establish which is the more effective drug at increasing mucociliary clearance and facilitating cough. Methods PATIENTSEleven patients (10 men) aged 36-77 years (mean 64 7) took part in the study. All patients undergoing thoracotomy were assessed by the author and recruited if they met the following entry criteria: (1) difficulty expectorating tenacious secretions, and (2) adequate analgesia to enable effective coughing.Patients were excluded ifthey had a recurrent laryngeal nerve palsy. Withdrawal criteria included (1) severe bronchospasm, (2) pulmonary oedema, (3) adult respiratory distress syndrome, (4) surgical emphysema, or (5) serious cardiac complications.The stud...

AARC Clinical Practice Guideline: Effectiveness of Pharmacologic Airway Clearance Therapies in Hospitalized Patients

“…37,41 One found no difference in the incidence of massive postoperative atelectasis in the nebulized N-acetylcysteine-treated group compared with the untreated group. 37 The other study found that the subjective impression of sputum viscosity and difficulty of expectoration decreased and the weight of expectorated sputum and S pO 2 improved in the nebulized N-acetylcysteine-treated group versus the saline-treated group during crossover.…”

Rapid Transport of Muco-Inert Nanoparticles in Cystic Fibrosis Sputum Treated with N -Acetyl Cysteine

“…RhDNase, which cleaves linear DNA in CF sputum, has been studied as an adjuvant for particle transport in CF sputum, but offered little to no improvement [6,7,19]. NAC, a mucolytic that cleaves disulfide bonds of mucin fibers, has been shown to reduce the viscosity of mucus/sputum in vitro [20] and in vivo [21]. Inhalation of a lysine salt of NAC, nacystelyn, has also been shown to be well tolerated by CF patients and to lead to a dose-dependent decrease in sputum viscoelasticity and solid content [22].…”

Anionic poly(amino acid)s dissolve F-actin and DNA bundles, enhance DNase activity, and reduce the viscosity of cystic fibrosis sputum

“…These polyelectrolyte filaments contribute to the viscoelastic properties of CF sputum by affecting both viscosity and elasticity, as quantified by parameters such as the dynamic storage and loss shear moduli (GЈ and GЉ, respectively). The viscoelastic moduli of CF sputum can be significantly lowered by application of agents such as DNase I, which degrades DNA (19); gelsolin, which fragments actin filaments (26); or thiolreducing agents and NaCl that act directly on mucin (6,9,16).…”