흉강경술을 위한 일측폐환기시 호기말 이산화탄소 분압은 동맥혈 이산화탄소 분압을 적절히 반영하는가 ? = Does End-tidal PCO2 Reflect Adequately Arterial PCO2 during One-lung Ventilation for Thoracoscopy ?

다국어 초록 (Multilingual Abstract)

Background: Maintenance of normal arterial carbon dioxide tension(PaCO₂) is not generally a problem if the same tidal volume can be maintained when changing from two-lung(TLV) to one-lung ventilation(OLV). However, there have been a few studies on the use of capnography in monitoring the adequacy of ventilation during one-lung anesthesia. We have therefore studied how closely end-tidal PCO,(PETCO₂) values reflect changes in PaCO in patients undergoing thoracoscopic sympathectomy during TLV and after transition to OLV.
Methods: We have measured arterial oxygen tension(PaO₂), PaCO₂ PETCO₂, and (PaCO₂-PETCO₂) in 24 adult, either sex, patients by infra-red spectrometry. They were measured after induction of anesthesia, in supine position(TLV_(sup)) after a lateral decubitus position(TLV_(lat)), at 15 minutes after left OLV(OLV_(LI)), after right OLV(OLV_(RI)), and at 10 minutes in the supine position re-positioned at the end of the operation(TLV_(rep)). Data were analyzed with a one-way analysis of variance with repeated measures followed by multiple comparision. The correlation between PaCO₂ and PETCO₂ were tested using linear regression.
Results: PaCO₂ did not significantly change, whereas PETCO₂ significantly decreased at OLV_(LI)OLV_(Rt) compared with TLVsup value (OLV_(LI)29.7 mmHg OLV_(Rt) 30.5 mmHg and TLV(sup) 33.6 mmHg; P$lt;0.05). Compared with TLV_(sup)(0.2 mmHg), (PaCO₂-PETCO₂) significantly increased at OLV_(Lt)OLV_(Rt) TLV,(3.7 mmHg, 2.3 mmHg, 3.5 mmHg). The correlation between PaCO₂. and PETCO₂. in these series is consistent.(r$gt;0.65, P$lt;0.0006)
Conclusions: In the patients undergoing thoracoscopic sympathectomy with TLV or OLV in the lateral decubitus position, PETCO₂ is a reliable estimate of the PaCO₂ However, when the operative time is prolonged the arterial PCO₂ may be more reliable than PETCO₂