[Effective high frequency jet ventilation setting for the preparation of internal thoracic artery for coronary artery bypass graft surgery].
Effective high frequency jet ventilation (HFJV) setting during the preparation of internal thoracic artery (ITA) was estimated in 35 patients who underwent coronary artery bypass graft (CABG) surgery. During ITA preparation, ventilation with the minimum lung movement without circulatory deterioration is necessary. Therefore, appropriate frequency, inspiratory time interval (Ti%) and working pressure (WP) for HFJV were investigated. Rising WP and prolonged Ti% provoked increasing tidal volume and decreasing PaCO2, whereas the lung extension disturbed the ITA preparation. By modifying the settings of frequency, Ti% and WP, we determined the frequency of 3Hz and Ti% of 50%. The correlation between WP at normocapnia and bodyweight (BW) is expressed in the following formula: WP = 0.16 x BW - 0.0003 (r = 0.72) Moreover satisfactory recording of end-tidal CO2 could not be obtained during HFJV. Therefore, we used transcutaneous CO2 (tc-CO2) analyzer. The coefficient between tc-CO2 and PaCO2 was 0.95, and tc-CO2 was useful as a non-invasive monitoring of PaCO2. There was little change in blood pressure, heart rate and cardiac output during HFJV. However mean pulmonary artery pressure (mPAP) increased significantly during hypercapnia especially when PaCO2 was over 50 mmHg. This suggests that mPAP may be more sensitive to PaCO2 compared with other circulatory parameters. HFJV with these settings produced good outcome for ventilation and circulation during the preparation of ITA.
Hayashi
M
M
Department of Anesthesiology, Nara Medical University, Kashihara.
Furuya
H
H
Shimomura
T
T
Hirai
K
K
Shimoyama
J
J
Kuro
M
M
Kitamura
S
S
Okuda
T
T
D000293:Adolescent; D000328:Adult; D002648:Child; D001026:Coronary Artery Bypass / Q000379:methods*; D006611:High-Frequency Jet Ventilation; D006801:Humans; D008875:Middle Aged; D013895:Thoracic Arteries