title: Co-administration of ephedrine prevents reductions in cardiac output and systemic oxygen delivery secondary to lung compression maneuvers during one-lung ventilation, without reducing arterial oxygenation.
abstract: OBJECTIVE
  We previously showed that compression of the nondependent lung during one-lung ventilation (OLV) in patients undergoing esophagectomy improves arterial oxygenation but impairs cardiac output (CO) and systemic oxygen delivery (DO(2)). The objective of this study was to test the hypothesis that the combination of nondependent lung compression and ephedrine improves arterial oxygenation without compromising DO(2).
  
  
  METHODS
  Twenty patients undergoing esophagectomy through a right thoracotomy were studied. Under general anesthesia, a left-sided double-lumen tube was placed, and the dependent lung was mechanically ventilated with a tidal volume of 8 ml/kg and a fraction of inspiratory oxygen of 0.8 during OLV. When nondependent lung was compressed by surgeons to improve surgical exposure, a randomly determined intravenous bolus of either ephedrine 4 mg (group E) or an identical volume of saline (group S) was administered. Arterial blood was sampled during two-lung ventilation (TLV), at 10 min of OLV (OLV1), and 5 min after nondependent lung compression (OLV2).
  
  
  RESULTS
  The initiation of OLV resulted in a significant drop in PaO(2) at OLV1 (group E, 136 ± 69 mmHg; group S, 138 ± 83 mmHg; P < 0.01) compared with TLV (group E, 404 ± 44 mmHg; group S; 367 ± 51 mmHg) and tended to improve at OLV2 (group E, 170 ± 63 mmHg; group S; 196 ± 121 mmHg). However, although CO and DO(2) significantly decreased in group S at OLV2 (4.0 ± 0.8 l/min, 621 ± 116 ml/min; P < 0.01) compared with OLV1 (5.1 ± 0.7 l/min, 811 ± 140 ml/min), there was no significant difference in these parameters in group E for the two time points.
  
  
  CONCLUSIONS
  Although arterial oxygenation was not significantly improved by the nondependent lung compression, the addition of intravenous ephedrine to nondependent lung compression prevented the decrease in systemic oxygen delivery without deterioration of arterial oxygenation during OLV in patients undergoing esophagectomy.
authors.affiliation: Department of Anesthesiology, Tokyo Medical and Dental University, Graduate School of Medical and Dental Sciences, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. ishikawa.mane@tmd.ac.jp
authors.forename: Seiji
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Fumi
authors.initials: F
authors.lastname: Makino
authors.forename: Satomi
authors.initials: S
authors.lastname: Kobinata
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ito
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Kawano
authors.forename: Koshi
authors.initials: K
authors.lastname: Makita
mesh_terms: D000368:Aged; D002302:Cardiac Output / Q000187:drug effects*; D004809:Ephedrine / Q000494:pharmacology*; D016629:Esophagectomy / Q000379:methods*; D005260:Female; D006801:Humans; D008168:Lung / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D012121:Respiration, Artificial; D013599:Systole; D013908:Thoracotomy
chemical_list: D004809:Ephedrine; D010100:Oxygen