Monitoring of PETCO2 during high frequency jet ventilation for laryngomicrosurgery.
In general, PETCO2 is well correlated with PaCO2 during spontaneous and conventional mechanical ventilation in normal lungs. However, it is known that during high frequency jet ventilation, PETCO2 may underestimate PaCO2 because of inadequate washout of the anatomical dead space by a small tidal volume and the relatively slow response time of infrared CO2 analyzers. The validity of PETCO2 as a reflection of PaCO2 was assessed during HFJV in 40 patients undergoing laryngeal microsurgery. HFJV was applied through an injector inserted into the trachea 6 cm below the vocal cord. PETCO2 was obtained from a sampling line placed 2 cm below the injector. Both PETCO2 and PaCO2 were measured simultaneously after decreasing the frequency from 100 beats per minute to 15 beats per minute 10 and 20 minutes after the commencement of HFJV. There was a strong correlation (r = 0.955, P < 0.001) and a good correspondence between the mean PETCO2 and PaCO2 values with an average difference of 1.93 +/- 1.21 mmHg and a limit of agreement from -0.49 to 4.35 mmHg. It is suggested that the PETCO2 obtained following a decrease in the jet frequency during HFJV could closely reflect PaCO2.
Kil
Hae Keum
HK
Department of Anesthesiology, Yonsei University College of Medicine, C.P.O. Box 8044, Seoul 120-752, Korea. hkkil@yumc.yonsei.ac.kr
Kim
Won Oak
WO
Choi
Hong Sik
HS
Nam
Yong Taeck
YT
D000328:Adult; D002245:Carbon Dioxide / Q000097:blood*; D006611:High-Frequency Jet Ventilation; D006801:Humans; D007830:Larynx / Q000601:surgery*; D008866:Microsurgery; D008875:Middle Aged; D008991:Monitoring, Physiologic
D002245:Carbon Dioxide