title: Unexplained fever after bilateral superficial cervical block in children undergoing cochlear implantation: an observational study.
abstract: OBJECTIVE
  In an effort to decrease postoperative opioid requirements, intraoperative bilateral superficial cervical plexus block (BSCPB) was recently adopted for all our children undergoing general anesthesia for bilateral simultaneous cochlear implantation (BSiCI). Several cases of early postoperative fever were noted after the adoption of BSCPB. Our aim was to determine if an association exists between BSCPB and early postoperative fever in children undergoing BSiCI. As a secondary outcome, we studied the efficacy of BSCPB in altering postoperative analgesic requirements.
  
  
  METHODS
  We conducted a retrospective cohort study of 91 consecutive children who underwent BSiCI. The series included 34 patients who received BSCPB (Block Group) and 57 patients who did not receive BSCPB (No-block Group).
  
  
  RESULTS
  The median age (range) was 15.4 months (eight months - 15 yr). A significant association was found between BSCPB and postoperative fever (P = 0.006). Eighteen (19.7%) children developed fever in the first 24 hr after surgery (Block Group: 12/34 [35%]; No-block Group: 6/57 [11%]; P = 0.006). The Block Group was 4.8 times more likely to develop early postoperative fever after adjusting for other variables (P = 0.004). The Block Group spent more days in hospital after surgery compared with the No-block Group (P = 0.043). Other vital signs showed no major deviation from the normal ranges, and daily physical examinations revealed no obvious source of infection in children who developed postoperative fever.
  
  
  CONCLUSIONS
  Bilateral superficial cervical plexus block may increase the risk of postoperative fever in children undergoing BSiCI. In this series, BSCPB was associated with a longer hospital admission. The etiology of the fever is undetermined, although it can be hypothesized that BSCPB resulted in unintended block of the phrenic nerves leading to diaphragmatic paralysis, atelectasis, and early postoperative fever in young children.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada. mazin.merdad@utoronto.ca
authors.forename: Mazin
authors.initials: M
authors.lastname: Merdad
authors.forename: Mark
authors.initials: M
authors.lastname: Crawford
authors.forename: Karen
authors.initials: K
authors.lastname: Gordon
authors.forename: Blake
authors.initials: B
authors.lastname: Papsin
mesh_terms: D000293:Adolescent; D002572:Cervical Plexus; D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000379:methods*; D015331:Cohort Studies; D005335:Fever of Unknown Origin / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007223:Infant; D007902:Length of Stay; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D010149:Postoperative Pain / Q000517:prevention & control*; D010791:Phrenic Nerve; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology; D012189:Retrospective Studies