title: Time-dependent changes in epidural catheter aspirate after injection of a local anesthetic.
abstract: OBJECTIVE
  A glucose check is used for investigation of a suspected accidental dural puncture in epidural anesthesia. However, glucose-positive clear fluid is sometimes aspirated from an epidural catheter in cases without clinical evidence of puncture. The goal of the study was to investigate time-dependent changes in the aspirate composition after injection of a local anesthetic into the epidural space.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Operating rooms at Hamamatsu University Hospital.
  
  
  METHODS
  The subjects were 30 patients (ASA I or II) undergoing surgery with combined epidural and general anesthesia.
  
  
  METHODS
  After epidural injection of local anesthetics, aspiration through the catheter was performed every 10min until fluid could not be aspirated. pH, Na, K, Cl, Ca and glucose were measured in fluid samples using a blood gas analysis apparatus.
  
  
  RESULTS
  No patients had pain or clinical signs suggesting dural puncture throughout the perioperative period. Fluid aspiration was possible in 15 patients (50%) after 10min and in 7, 3, 2 and 2 patients after 20, 30, 40 and 50min, respectively. Glucose was detected in each aspirated fluid sample and gradually increased with time to become closer to the level in cerebrospinal fluid (CSF). Each electrolyte also changed to approach the level found in CSF.
  
  
  CONCLUSIONS
  A glucose check may increase the risk of a false-positive finding for accidental dural puncture with increasing time after local anesthetic injection. Conversely, detection of glucose at the time of epidural catheter placement may provide useful information for detection of accidental dural puncture.
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine. Electronic address: etsuyo-hori@hamamatsu.jrc.or.jp.
authors.forename: Etsuyo
authors.initials: E
authors.lastname: Hori
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Kurita
authors.affiliation: Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine.
authors.forename: Shigehito
authors.initials: S
authors.lastname: Sato
mesh_terms: D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural / Q000009:adverse effects* / Q000379:methods*; D000768:Anesthesia, General; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001784:Blood Gas Analysis; D004388:Dura Mater / Q000293:injuries; D004573:Electrolytes / Q000134:cerebrospinal fluid; D004824:Epidural Space; D005189:False Positive Reactions; D005260:Female; D005947:Glucose / Q000134:cerebrospinal fluid; D006801:Humans; D007268:Injections, Epidural; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period
chemical_list: D000779:Anesthetics, Local; D004573:Electrolytes; D005947:Glucose
keywords: CSF; Dural puncture; Epidural anesthesia; Glucose