Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Hagara, B.
Rocuronium bromide pharmacokinetics and pharmacodynamics during Acute Normovolemic Hemodilution (ANH)
[ Dissertation ] Graz Medical University ; 2005. pp.33.
- Autor*innen der Med Uni Graz:
- Hagara Bianca
- Betreuer*innen:
- Metzler Helfried
- Altmetrics:
- Abstract:
- BACKGROUND: Acute normovolemic heodilution is an effective method for reducing ar avoiding allogenic blood transfusion during surgery. ANH is often associated with changes in hemodynamics and blood chemistry that could possibly alter the pharmacokinetics and pharmocodynamics of neuromuscular blocking agents. This might lead to overdosing of underdosing of the NMBD. METHODs: Twenty eight consecutive, ASA I-III, patients aged 50-70 yr, undergoing general anethesia with ANH for scheduled elective radical prostatectomy or radical cystectomy were included n the study. Patients were equally divided in two groups; the pharmacodynamics and pharmacokinetics groups. Each recruited ANH patient was matched, in another two pharmacodynamics and pharmacokinetics control groups for gender, ASA classification, approximate age and body weight with a patient undergoing scheduled elective surgical procedure without ANH. Oral midazolam 3.75-7.5 mg was the only premedication given 1h before anesthesia induction. Anesthesia was induced with propofol 2-3 mg/kg i.v. and a remifentanil 0.1-0.3 g kg-1 min-1 infusion until the eyelash reflex was lost. Following induction of anesthesia and before the start of surgery, 15 ml/kg blood (approximately 20/ of blood volume) up to a maximum 1000ml of the patients blood were withdrawn from the cubital vein and stored in an acid citrate in dextrose solution reservoir bag to be simultaneously replaced by 1000ml Hydoxyethyl Starch 130/0.4, rapidly infused via a separate venous cannula. The hematocrit (Hct) target after hemodilution was 25%-30%. The neuromuscular block at the adductor pollicis muscle was evaluated using the Relaxometer mechanomyograph (Groningen University Holland). RESULTS: Our study showed that the potency of rocuroium is increased during ANH, as indicated by a parallel shift to the left of rocuronium dose-response curve, indicating an enhancement of rocuronium neuromuscular block. The slope of the dose-response curve for rocuronium in the hemodilution group was not significantly different from the control. There were significant differences in ED50, ED90 and ED95 between the two groups. The ED50, ED90 and ED95 of rocuronium in the hemodilution group were decreased by 53.3%, 24.4% and 13% respectively, compared with the control group.