title: The effect of exogenous epinephrine on the incidence of hypotensive/bradycardic events during shoulder surgery in the sitting position during interscalene block.
abstract: Sudden hypotensive and/or bradycardic events (HBE) have been reported in 13%-28% of patients undergoing shoulder surgery in the sitting position during interscalene block. The Bezold-Jarisch reflex is the most likely mechanism for these events. It has been hypothesized that exogenous epinephrine might be a key component to the occurrence of HBE. We conducted this prospective, randomized study to verify this hypothesis. Patients received a local anesthetic solution with (Group E; n = 55) or without (Group P; n = 55) epinephrine for interscalene block; no further exogenous epinephrine was administered. Blood pressure control was achieved with IV urapidil, a peripheral vasodilator, as needed. The incidence of HBE was 11% in Group P versus 29% in Group E (P = 0.015). Increased intraoperative heart rate and arterial blood pressure were recorded in Group E (P = 0.000). Urapidil was administered to 13% of Group P and to 31% of Group E patients (P = 0.018). Urapidil administration induced a HBE in 4% of Group P and in 5% of Group E patients. We conclude that exogenous epinephrine is involved in the development of HBE in this setting.
  
  
  CONCLUSIONS
  Sudden hypotensive and/or bradycardic events occur during shoulder surgery in the sitting position during interscalene block. In this study, we demonstrated that the presence of epinephrine in the local anesthetic mixture significantly increases the incidence of these events.
authors.affiliation: *Department of Anesthesiology and †Cardiology Unit, Centro Traumatologico Ortopedico, Azienda Ospedaliera Careggi, Firenze, Italia.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sia
authors.forename: Francesca
authors.initials: F
authors.lastname: Sarro
authors.forename: Antonella
authors.initials: A
authors.lastname: Lepri
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bartoli
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced*; D004837:Epinephrine / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000139:chemically induced*; D007431:Intraoperative Complications / Q000139:chemically induced*; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D010879:Piperazines / Q000008:administration & dosage / Q000009:adverse effects; D011187:Posture; D011446:Prospective Studies; D012785:Shoulder Joint / Q000601:surgery*; D014662:Vasoconstrictor Agents / Q000009:adverse effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000779:Anesthetics, Local; D010879:Piperazines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C015568:urapidil; D004837:Epinephrine