title: Time course of the effects of cervical epidural anesthesia on pulmonary function.
abstract: OBJECTIVE
  During cervical epidural anesthesia the C4, C5, and sometimes C3 nerve roots are anesthetized. One might therefore expect pulmonary compromise due to the block of the phrenic nerve if anesthesia extends to C3. This study was conducted to measure the effects of cervical epidural anesthesia using 2% lidocaine on pulmonary function, with specific attention given to the time course of pulmonary changes in relation to spread of analgesia.
  
  
  METHODS
  Fifteen adult patients without preexisting lung disease undergoing carotid endarterectomy, breast surgery, or cervical epidural steroid injection were enrolled. Cervical epidural anesthesia was performed at the C7-T1 interspace using 300 mg lidocaine with epinephrine. Pulmonary function, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), maximum inspiratory pressure (MIP), and SpO2 while breathing room air were measured prior to and 5, 10, 20, and 40 minutes after lidocaine injection.
  
  
  RESULTS
  Analgesia to pinprick reached median dermatomes of C3 to T8 (range: C2-T12) by 20 minutes after lidocaine injection. FEV1 and FVC decreased approximately 12-16% between 20 and 40 minutes after injection. Maximum inspiratory pressure and SpO2 did not significantly change.
  
  
  CONCLUSIONS
  Cervical epidural anesthesia using 300 mg lidocaine results in measurable reduction in bedside pulmonary functions concomitant with the spread of analgesia to the C3 dermatome. These changes were complete 20 minutes after lidocaine injection. In patients without preexisting lung disease, these changes were not clinically significant, except in one patient. We conclude that motor block of the phrenic nerve is incomplete under the conditions of this study.
authors.affiliation: Department of Anesthesiology, Loyola University Medical Center, Maywood, Illinois, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Stevens
authors.forename: K
authors.initials: K
authors.lastname: Frey
authors.forename: T
authors.initials: T
authors.lastname: Sheikh
authors.forename: T C
authors.initials: TC
authors.lastname: Kao
authors.forename: M
authors.initials: M
authors.lastname: Mikat-Stevens
authors.forename: M
authors.initials: M
authors.lastname: Morales
mesh_terms: D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural / Q000009:adverse effects; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008012:Lidocaine / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D014797:Vital Capacity
chemical_list: D008012:Lidocaine