title: Neuromuscular blockade with rocuronium bromide increases the tolerance of acute normovolemic anemia in anesthetized pigs.
abstract: BACKGROUND
  The patient's individual anemia tolerance is pivotal when blood transfusions become necessary, but are not feasible for some reason. To date, the effects of neuromuscular blockade (NMB) on anemia tolerance have not been investigated.
  
  
  METHODS
  14 anesthetized and mechanically ventilated pigs were randomly assigned to the Roc group (3.78 mg/kg rocuronium bromide followed by continuous infusion of 1 mg/kg/min, n = 7) or to the Sal group (administration of the corresponding volume of normal saline, n = 7). Subsequently, acute normovolemic anemia was induced by simultaneous exchange of whole blood for a 6% hydroxyethyl starch solution (130/0.4) until a sudden decrease of total body O(2) consumption (VO(2)) indicated a critical limitation of O(2) transport capacity. The Hb concentration quantified at this time point (Hb(crit)) was the primary endpoint of the protocol. Secondary endpoints were parameters of hemodynamics, O(2) transport and tissue oxygenation.
  
  
  RESULTS
  Hb(crit) was significantly lower in the Roc group (2.4 ± 0.5 vs. 3.2 ± 0.7 g/dl) reflecting increased anemia tolerance. NMB with rocuronium bromide reduced skeletal muscular VO(2) and total body O(2) extraction rate. As the cardiac index increased simultaneously, total body VO(2) only decreased marginally in the Roc group (change of VO(2) relative to baseline -1.7 ± 0.8 vs. 3.2 ± 1.9% in the Sal group, p < 0.05).
  
  
  CONCLUSIONS
  Deep NMB with rocuronium bromide increases the tolerance of acute normovolemic anemia. The underlying mechanism most likely involves a reduction of skeletal muscular VO(2). During acellular treatment of an acute blood loss, NMB might play an adjuvant role in situations where profound stages of normovolemic anemia have to be tolerated (e.g. bridging an unexpected blood loss until blood products become available for transfusion).
authors.affiliation: Clinic of Anesthesiology, Intensive Care Medicine and Pain Management, J.W. Goethe University Hospital, Frankfurt a.M., Germany.
authors.forename: A
authors.initials: A
authors.lastname: Pape
authors.forename: H
authors.initials: H
authors.lastname: Kertscho
authors.forename: P
authors.initials: P
authors.lastname: Stein
authors.forename: M
authors.initials: M
authors.lastname: Lossen
authors.forename: O
authors.initials: O
authors.lastname: Horn
authors.forename: S
authors.initials: S
authors.lastname: Kutschker
authors.forename: B
authors.initials: B
authors.lastname: Zwissler
authors.forename: O
authors.initials: O
authors.lastname: Habler
mesh_terms: D000732:Androstanols / Q000494:pharmacology*; D000740:Anemia / Q000188:drug therapy / Q000503:physiopathology*; D000758:Anesthesia; D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D006438:Hemodilution; D008297:Male; D023421:Models, Animal; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects*; D000077123:Rocuronium; D013552:Swine
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium