title: An observational cohort study of the meniscus test to detect intravascular epidural catheters in pregnant women.
abstract: BACKGROUND
  The meniscus test is a rapid non-pharmacologic method of confirming epidural catheter placement by observing a normal saline meniscus while physically manipulating the catheter. The aim of this study was to assess whether the meniscus test improves diagnostic accuracy of aspiration to detect intravascular or intrathecal placement of epidural catheters in pregnant women.
  
  
  METHODS
  In this prospective observational study, parturients at >or= 36 weeks of gestation were recruited. In the sitting position, participants received a multiorifice epidural catheter for elective cesarean delivery or labor analgesia. After aspiration was confirmed to be negative for blood and cerebrospinal fluid, the meniscus test was performed. Subsequently, a pharmacologic test dose was given with 1.5% lidocaine 3 mL and epinephrine 15 microg. Intravascular placement was diagnosed if the patient experienced an increase in heart rate >or= 20 beats/min within 2 min with or without tinnitus, metallic taste, dizziness, palpitations, headache, or anxiety.
  
  
  RESULTS
  The overall intravascular catheter rate was 5.7% (24/419). The rate of intravascular catheter location not detected by aspiration was 0.95% (4/419). Given negative catheter aspiration, the meniscus test demonstrated 25% sensitivity, 87.5% specificity, and 1.9% positive predictive value for intravascular catheter insertion. No intrathecal catheters were observed.
  
  
  CONCLUSIONS
  For obstetric patients in the sitting position, the meniscus test does not improve diagnostic accuracy of aspiration for detecting intravascular multiorifice epidural catheter placement.
authors.affiliation: Department of Anesthesiology, Division of Obstetric Anesthesiology, Women's Hospital, University of Michigan Health System, Ann Arbor, Michigan 48109-5278, USA. monicar@med.umich.edu
authors.forename: M N
authors.initials: MN
authors.lastname: Servin
authors.forename: J M
authors.initials: JM
authors.lastname: Mhyre
authors.forename: M L V H
authors.initials: ML
authors.lastname: Greenfield
authors.forename: L S
authors.initials: LS
authors.lastname: Polley
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural / Q000295:instrumentation*; D016362:Analgesia, Obstetrical / Q000295:instrumentation*; D001808:Blood Vessels / Q000293:injuries*; D002404:Catheterization / Q000009:adverse effects*; D002985:Clinical Protocols; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014950:Wounds, Penetrating / Q000175:diagnosis* / Q000517:prevention & control