title: The influence of deliberate hypotension on splanchnic perfusion balance with use of either isoflurane or esmolol and nitroglycerin.
abstract: Various techniques to induce deliberate hypotension (DH) have different influences on splanchnic perfusion. The aim of our study was to determine whether splanchnic perfusion is clinically impaired during DH by using either isoflurane (ISO) or a combination of esmolol and nitroglycerin (E/N). We randomized 16 patients undergoing elective maxillofacial surgery to receive either ISO (0.7%-1.8%) or E (105 g x kg(-1) x min(-1)) and N (1-6 mg/h) to induce DH. General anesthesia was performed in both groups by IV midazolam 0.07 mg/kg, fentanyl 0.003 mg/kg, propofol 1.5 mg/kg, and vecuronium 0.1 mg/kg followed by a propofol infusion with 6 mg x kg(-1) x h(-1). After the induction of anesthesia, a gastric tonometer (TRIP NGS Catheter) and a radial artery catheter were inserted. Baseline values of gastric intramucosal pH (pHi) were determined 60 min after placement of the catheter and before the induction of DH. The pHi values were calculated every 60 min until DH was discontinued. In both groups, DH was satisfactorily established. None of the pHi values calculated was less than 7.37 in the E/N or 7.41 in the ISO group. Arterial blood lactate levels did not increase in any of the patients. We conclude that neither method of producing DH compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate.
  
  
  CONCLUSIONS
  Neither the isoflurane nor the esmolol/nitroglycerin method of producing deliberate hypotension compromises splanchnic tissue oxygen balance in healthy patients. Furthermore, overall organ perfusion was sufficient in both groups, because none of the patients showed an increase in blood lactate.
authors.affiliation: Department of Anesthesiology and General Intensive Care, Vienna General Hospital, University of Vienna, Austria. dorothea.andel@akh-wien.ac.at
authors.forename: D
authors.initials: D
authors.lastname: Andel
authors.forename: H
authors.initials: H
authors.lastname: Andel
authors.forename: K
authors.initials: K
authors.lastname: Hörauf
authors.forename: D
authors.initials: D
authors.lastname: Felfernig
authors.forename: W
authors.initials: W
authors.lastname: Millesi
authors.forename: M
authors.initials: M
authors.lastname: Zimpfer
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007023:Hypotension, Controlled / Q000379:methods*; D007530:Isoflurane / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology*; D019647:Oral Surgical Procedures; D011412:Propanolamines / Q000494:pharmacology*; D013152:Splanchnic Circulation / Q000187:drug effects* / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000319:Adrenergic beta-Antagonists; D018685:Anesthetics, Inhalation; D011412:Propanolamines; D014665:Vasodilator Agents; D002245:Carbon Dioxide; D007530:Isoflurane; D005996:Nitroglycerin; C036604:esmolol