Effects of isoflurane on oxygenation during one-lung ventilation in pulmonary emphysema patients.
BACKGROUND
Hypoxic pulmonary vasoconstriction has an important role in human one-lung ventilation (OLV) in the lateral decubitus position under general anesthesia. During OLV, inhalational anesthesia may inhibit hypoxic pulmonary vasoconstriction and the decrease in arterial oxygenation. We studied the effect of isoflurane administration on arterial oxygen tension in chronic obstructive pulmonary disease patients.


METHODS
Ten patients who had thoracoscopic laser ablation of bullous emphysema were studied. Patients received 2% isoflurane in oxygen from induction until the first 20 min of OLV in the lateral decubitus position, then were switched to 1% isoflurane lasting 20 min and next were switched to 0.5% isoflurane lasting 20 min. After each 20-min inhalation, pulmonary and hemodynamic parameters were measured. The given concentrations for isoflurane were merely vapor meter concentrations.


RESULTS
PaO2/FIO2, Qs/Qt respiratory rate peak inspiratory pressure and PaCO2 showed no significant changes at each point of isoflurane. Expiratory tidal volume significantly decreased (P < 0.05) with 0.5% isoflurane compared to that with 2% isoflurane. Cardiac output, mean arterial pressure, mean pulmonary arterial pressure, systemic vascular resistance and pulmonary vascular resistance showed no significant changes at each point of isoflurane.


CONCLUSIONS
In patients with pulmonary emphysema, arterial oxygenation is not affected by low isoflurane concentration during OLV in the lateral decubitus position.
Satoh
D
D
Department of Anesthesiology, Tohoku University School of Medicine, Sendai, Japan.
Sato
M
M
Kaise
A
A
Hagiwara
Y
Y
Saishu
T
T
Hashimoto
Y
Y
D000368:Aged; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000187:drug effects; D004724:Endoscopy; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D007320:Inspiratory Capacity / Q000187:drug effects; D007530:Isoflurane / Q000008:administration & dosage*; D053685:Laser Therapy; D008168:Lung / Q000098:blood supply; D008173:Lung Diseases, Obstructive / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects; D011187:Posture; D011312:Pressure; D011651:Pulmonary Artery / Q000187:drug effects; D011656:Pulmonary Emphysema / Q000601:surgery*; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D012121:Respiration, Artificial / Q000379:methods*; D013906:Thoracoscopy; D013990:Tidal Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000502:physiology
D018685:Anesthetics, Inhalation; D002245:Carbon Dioxide; D007530:Isoflurane; D010100:Oxygen