title: Carotid sinus nerve blockade during carotid surgery: a randomised controlled trial.
abstract: OBJECTIVE
  we investigated whether carotid sinus nerve infiltration with lignocaine reduced blood pressure lability during the first 24h following carotid endarterectomy (CEA).
  
  
  METHODS
  prospective randomised double-blind controlled trial.
  
  
  METHODS
  eighty patients undergoing CEA for significant symptomatic stenosis of the internal carotid artery.
  
  
  METHODS
  after initial dissection, 5 ml of 1% lignocaine or normal saline placebo according to randomisation was infiltrated around the carotid sinus nerve. Blood pressure was measured by intra-arterial cannula during surgery and for four hours afterwards every 15 min, then manually, hourly for 18 h.
  
  
  RESULTS
  patients having excision of the carotid sinus nerve were grouped separately for analysis: 29 patients had lignocaine, 33 placebo and 17 excision (one early death with incomplete data was excluded). Mean systolic, diastolic and pulse pressures did not differ significantly between the three groups before carotid sinus nerve infiltration. After infiltration, those patients who had carotid sinus nerve excision, had significantly higher systolic [mean (SD)=155 (16)mmHg] and diastolic [75 (9)mmHg] pressures than those receiving LA [systolic=136 (15)mmHg, diastolic=65 (10)mmHg] or placebo [systolic=136 (19)mmHg, diastolic=65 (9)mmHg], (p<0.005 ANOVA). Nerve excision also resulted in wider variability of blood pressure as defined by the mean of individual standard deviations (systolic=25 mmHg, diastolic=13 mmHg) compared to LA (systolic=19 mmHg, diastolic=12 mmHg) or placebo (systolic=18 mmHg, diastolic=10 mmHg) (p<0.05 ANOVA). Normotensive patients had significantly lower mean diastolic pressures (p<0.001 ANOVA) and variability (p<0.05) if they received lignocaine although this did not influence pulse pressure.
  
  
  CONCLUSIONS
  lignocaine injection of the carotid sinus nerve has no benefit in those patients with existing treated hypertension and only marginal effects in normotensives. It is more important to preserve the carotid sinus nerve if possible.
authors.affiliation: Department of Surgery, University Hospital of South Manchester, Wythenshawe, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Fearn
authors.forename: A J
authors.initials: AJ
authors.lastname: Mortimer
authors.forename: E B
authors.initials: EB
authors.lastname: Faragher
authors.forename: C N
authors.initials: CN
authors.lastname: McCollum
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002343:Carotid Artery, Internal / Q000187:drug effects / Q000294:innervation* / Q000601:surgery*; D002346:Carotid Sinus / Q000187:drug effects* / Q000294:innervation* / Q000601:surgery; D016893:Carotid Stenosis / Q000601:surgery*; D004311:Double-Blind Method; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D011446:Prospective Studies
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine