Stroke volume-directed administration of hydroxyethyl starch   (HES 130/0.4) and Ringer’s acetate in prone position   during neurosurgery: a randomized controlled trial.
OBJECTIVE
General anesthesia in the prone position is associated with hypotension. We studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer’s acetate (RAC) in neurosurgical patients operated on in a prone position to determine the volumes required for stable hemodynamics and possible coagulatory effects.


METHODS
Thirty elective neurosurgical patients received either HES (n = 15) or RAC (n = 15). Before positioning, SV measured by arterial pressure waveform analysis was maximized by fluid boluses until SV did not increase more than 10 %. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups. Thromboelastometry assessed coagulation. Mann–Whitney U test, Wilcoxon signed-rank test, ANOVA on ranks, and a linear mixed model were applied.


RESULTS
Comparable hemodynamics were achieved with the mean cumulative (SD) boluses of HES or RAC 240 (51) or 267 (62) ml (P = 0.207) before positioning, 340 (124) or 453 (160) ml (P = 0.039) 30 min after positioning, and 440 (229) or 653 (368) ml at the end of surgery (P = 0.067). The mean dose of basal RAC infusion was 813 (235) and 868 (354) ml (P = 0.620) in the HES and RAC group, respectively. Formation and maximum strength of the fibrin clot were decreased in the HES group. Intraoperative blood loss was comparable between groups (P = 0.861).


CONCLUSIONS
The amount of RAC needed in the prone position was 25 % greater. The cumulative dose of 440 ml HES induced a slight disturbance in fibrin formation and clot strength. We suggest cautious administration of HES during neurosurgery.
Ann-Christine
AC
Lindroos
Tomohisa
T
Niiya
Tarja
T
Randell
Tomi T
TT
Niemi
D000328:Adult; D000368:Aged; D001777:Blood Coagulation / Q000187:drug effects; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage / Q000627:therapeutic use*; D007552:Isotonic Solutions / Q000008:administration & dosage* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D056888:Patient Positioning; D010952:Plasma Substitutes / Q000008:administration & dosage* / Q000627:therapeutic use; D016684:Prone Position; D013318:Stroke Volume / Q000187:drug effects*; D013916:Thrombelastography
C485123:HES 130-0.4; D006895:Hydroxyethyl Starch Derivatives; D007552:Isotonic Solutions; D010952:Plasma Substitutes; C028570:Ringer's acetate