Impact of laryngeal mask airway and tracheal tube on pulmonary function during the early postoperative period
The tracheal tube (TT) produces reversible bronchoconstriction and increases pulmonary airway resistance compared to the laryngeal mask airway (LMA). The possible persistence of this effect in the postoperative period has not been studied. The aim of this study was to compare the early postoperative pulmonary function in healthy patients undergoing minor surgical procedures with the LMA or with the TT. Methods:
Sixty patients scheduled for saphenous vein stripping under general anaesthesia were randomised to receive the LMA or the TT. Before anaesthesia and 20 min after LMA or TT removal, pulse oxymetry values (SpO2) were recorded and patients performed forced spirometry in the supine position. Results:
Preoperative pulmonary function was normal in both groups. There were no differences between groups in the preoperative respiratory function test and SpO2. Following surgery SpO2, forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) decreased in both groups. The FEV1/FVC did not change in either of the groups. In the TT group, compared to patients using the LMA, there was a greater relative decrease of SpO2 (2.7 ± 2.7% vs. 1.3 ± 2.2%, P=0.017), FEV1 (17.6 ± 12.2% vs. 8 ± 17.4%, P=0.008), FVC (15.8 ± 12.4% vs. 9 ± 13.4%, P=0.023) and PEF (20.6% ± 15.3% vs. 8.1 ± 33.3%, P=0.033). Conclusions:
This study demonstrates greater early postoperative respiratory restrictive syndrome and lower arterial oxygen saturation following tracheal intubation compared to LMA use in patients without respiratory disease.
Document Type: Research Article
Affiliations: Department of Anaesthesia, Intensive Care and Emergency, Casa di Cura ‘Poliambulanza’, Brescia, Italy
Publication date: May 1, 2002