title: Postoperative volume balance: does stroke volume increase in Trendelenburg's position?
abstract: In healthy humans, stroke volume (SV) and cardiac output (CO) do not increase with expansion of the central blood volume by head-down tilt or administration of fluid. Here, we exposed 85 patients to Trendelenburg's position about one hour after surgery while cardiovascular variables were determined non-invasively by Modelflow. In Trendelenburg's position, SV (83 ± 19 versus 89 ± 20 ml) and CO (6·2 ± 1·8 versus 6·8 ± 1·8 l/min; both P<0·05) increased, while heart rate (75 ± 15 versus 76 ± 14 b min-1) and mean arterial pressure were unaffected (84 ± 15 versus 84 ± 16 mmHg). For the 33 patients (39%) with a > 10% increase in SV (from 78 ± 16 to 90 ± 17 ml) corresponding to an increase in CO from 5·9 ± 1·5 to 6·9 ± 1·6 l min-1(P<0·05) when tilted head-down, administration of 250 ml Ringer's lactate solution increased SV (to 88 ± 18 ml) and CO (to 6·8 ± 1·7 l min-1). In conclusion, determination of SV and/or CO in Trendelenburg's position can be used to evaluate whether a patient is in need of IV fluid as here exemplified after surgery.
authors.affiliation: Department of Anaesthesia, The Abdominal Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Frost
authors.affiliation: Department of Anaesthesia, The Abdominal Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: C R
authors.initials: CR
authors.lastname: Mortensen
authors.affiliation: Department of Anaesthesia, The Abdominal Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: N H
authors.initials: NH
authors.lastname: Secher
authors.affiliation: Department of Anaesthesia, The Abdominal Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: H B
authors.initials: HB
authors.lastname: Nielsen
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000762:Anesthesia Recovery Period; D062186:Arterial Pressure; D005260:Female; D005440:Fluid Therapy; D018475:Head-Down Tilt; D006339:Heart Rate; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D007262:Infusions, Intravenous; D007552:Isotonic Solutions / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects*; D056888:Patient Positioning; D018579:Patient Selection; D011182:Postoperative Care / Q000379:methods; D000077331:Ringer's Solution; D013318:Stroke Volume; D013997:Time Factors; D055815:Young Adult
chemical_list: D007552:Isotonic Solutions; D000077331:Ringer's Solution
keywords: anaesthesia; cardiac output; fluid balance; stroke volume; surgery