title: Nitroglycerine and patient position effect on central, hepatic and portal venous pressures during liver surgery.
abstract: BACKGROUND
  To reduce blood loss during liver surgery, a low central venous pressure (CVP) is recommended. Nitroglycerine (NG) with its rapid onset and offset can be used to reduce CVP. In this study, the effect of NG on portal and hepatic venous pressures (PVP and HVP) in different body positions was assessed.
  
  
  METHODS
  Thirteen patients undergoing liver resection were studied. Cardiac output (CO), mean arterial pressure (MAP) and CVP were measured. PVP and HVP were measured using tip manometer catheters at baseline (BL) in horizontal position; during NG infusion, targeting a MAP of 60 mmHg, with NG infusion and the patient placed in 10 head-down position.
  
  
  RESULTS
  NG infusion reduced HVP from 9.7 ± 2.4 to 7.2 ± 2.4, PVP from 12.3 ± 2.2 to 9.7 ± 3.0 and CVP from 9.8 ± 1.9 to 7.2 ± 2.1 mmHg at BL. Head-down tilt during ongoing NG resulted in increases in HVP to 8.2 ± 2.1, PVP to 10.7 ± 3 and CVP to 11 ± 1.9 mmHg. CO at BL was 6.3 ± 1.1, which was reduced by NG to 5.8 ± 1.2. Head-down tilt together with NG infusion restored CO to 6.3 ± 1.0 l/min.
  
  
  CONCLUSIONS
  NG infusion leads to parallel reductions in CVP, HVP and PVP at horizontal body position. Thus, CVP can be used to guide NG dosage and fluid administration at horizontal position. NG infusion can be used to reduce HVP. Head-down tilt can be used during NG infusion to improve both blood pressure and CO without substantial increase in liver venous pressure. In head-down tilt, CVP dissociates from HVP and PVP.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Institutes of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Sand
authors.forename: S
authors.initials: S
authors.lastname: Lundin
authors.forename: M
authors.initials: M
authors.lastname: Rizell
authors.forename: J
authors.initials: J
authors.lastname: Wiklund
authors.forename: O
authors.initials: O
authors.lastname: Stenqvist
authors.forename: E
authors.initials: E
authors.lastname: Houltz
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D016063:Blood Loss, Surgical; D001794:Blood Pressure / Q000187:drug effects*; D002277:Carcinoma / Q000556:secondary / Q000601:surgery; D002302:Cardiac Output / Q000187:drug effects; D005260:Female; D006498:Hepatectomy; D006503:Hepatic Veins; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology; D006975:Hypertension, Portal / Q000503:physiopathology; D007432:Intraoperative Period; D008113:Liver Neoplasms / Q000556:secondary / Q000601:surgery; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology*; D056888:Patient Positioning; D011169:Portal Vein; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000959:Antihypertensive Agents; D014665:Vasodilator Agents; D005996:Nitroglycerin