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Relationship between arterial and end‐tidal carbon dioxide pressures during anesthesia using a laryngeal tube
Author(s) -
Lee J. S.,
Nam S. B.,
Chang C. H.,
Han D. W.,
Lee Y. W.,
Shin C. S.
Publication year - 2005
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.2005.00698.x
Subject(s) - anesthesia , medicine , ventilation (architecture) , endotracheal tube , mechanical ventilation , intubation , carbon dioxide , chemistry , physics , organic chemistry , thermodynamics
Background: The Laryngeal Tube ® (LT), (VBM Medizintechnik, Sulz, Germany) is a relatively new supraglottic device for controlling the airway. Arterial carbon dioxide tension (PaCO 2 ) can be estimated by monitoring the end‐tidal tension of carbon dioxide (PETCO 2 ). The relationship between PETCO 2 and PaCO 2 during controlled ventilation via the LT has not been reported. Methods: During general anesthesia, 45 patients were mechanically ventilated using an LT. PETCO 2 and PaCO 2 were measured once PETCO 2 had reached a steady state. The LT was then removed and the trachea intubated using an endotracheal tube (ETT), and the identical ventilatory variables were resumed. Following stabilization, PETCO 2 was again determined and PaCO 2 estimated. Results: The mean PETCO 2 and PaCO 2 values were 4.43 ± 0.26 kPa and 4.67 ± 0.32 kPa, respectively, during LT ventilation, and 4.36 ± 0.23 kPa and 4.61 ± 0.26 kPa, respectively, during ETT ventilation. Analysis of differences between the PETCO 2 and PaCO 2 values using the Bland and Altman method revealed a bias ± precision of 0.24 ± 0.15 kPa for LT and 0.27 ± 0.15 kPa for ETT. The root mean square error was 0.28 for the LT and 0.30 for the ETT. Conclusion: This study suggests that for healthy adult patients mechanically ventilated via the LT, the PETCO 2 value reflects the PaCO 2 value as closely as when patients are ETT ventilated, allowing capnometry to be used to evaluate the adequacy of ventilation.