title: The volume of lactated Ringer's solution required to maintain preload and cardiac index during open and laparoscopic surgery.
abstract: BACKGROUND
  Recent studies have emphasized the importance of perioperative fluid restriction. However, fluid restriction regimens may increase the likelihood of insufficient perioperative fluid administration or may result in excess intravascular crystalloid replacement. We postulate that the use of transesophageal echocardiography may reduce the amount of crystalloid administered during open and laparoscopic colorectal surgery.
  
  
  METHODS
  Fifteen ASA I and II patients scheduled for open colorectal surgery, and 15 patients scheduled for laparoscopic surgery were studied. Lactated Ringer's solution was infused during the procedures. Left ventricular end diastolic volume index (LVEDVI) and cardiac index were assessed throughout surgery and used to guide the rate of lactated Ringer's solution administration. Statistical analysis was performed with Student's t-test for unpaired samples.
  
  
  RESULTS
  The rate of crystalloid administration required to maintain baseline LVEDVI and cardiac index was 5.9 +/- 2 mL x kg(-1) x h(-1) for open surgery and 3.4 +/- 0.8 mL x kg(-1) x h(-1) for laparoscopic surgery (P < 0.01). This slower rate for laparoscopic surgery was offset by the longer surgical duration.
  
  
  CONCLUSIONS
  The rate of crystalloid solution to maintain baseline LVEDVI and cardiac index was greater in open surgery than laparoscopic surgery, and lower than commonly recommended for colorectal surgery.
authors.affiliation: Department of Anesthesiology, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile. mconcha@med.puc.cl
authors.forename: Mario R
authors.initials: MR
authors.lastname: Concha
authors.forename: Verónica F
authors.initials: VF
authors.lastname: Mertz
authors.forename: Luis I
authors.initials: LI
authors.lastname: Cortínez
authors.forename: Katya A
authors.initials: KA
authors.lastname: González
authors.forename: Jean M
authors.initials: JM
authors.lastname: Butte
authors.forename: Francisco
authors.initials: F
authors.lastname: López
authors.forename: George
authors.initials: G
authors.lastname: Pinedo
authors.forename: Alvaro
authors.initials: A
authors.lastname: Zúñiga
mesh_terms: D000368:Aged; D001810:Blood Volume / Q000502:physiology*; D002302:Cardiac Output / Q000187:drug effects*; D002306:Cardiac Volume / Q000187:drug effects / Q000502:physiology; D003106:Colon / Q000601:surgery; D000077324:Crystalloid Solutions; D013505:Digestive System Surgical Procedures; D017548:Echocardiography, Transesophageal; D004809:Ephedrine / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D020896:Hypovolemia / Q000517:prevention & control; D007552:Isotonic Solutions / Q000008:administration & dosage* / Q000627:therapeutic use; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D019990:Perioperative Care; D010952:Plasma Substitutes / Q000008:administration & dosage*; D000077325:Ringer's Lactate; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000627:therapeutic use; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions; D010952:Plasma Substitutes; D000077325:Ringer's Lactate; D014662:Vasoconstrictor Agents; D004809:Ephedrine