title: Development and evaluation of a score to predict difficult epidural placement during labor.
abstract: OBJECTIVE
  Difficult epidural placement (DEP) during labor may be distressing for the patient and may increase the risk of dural puncture. A score predicting DEP based on the combination of individual risk factors could identify high-risk patients. This study aimed to identify risk factors for DEP and build a prediction score.
  
  
  METHODS
  Three hundred thirty patients were prospectively included. Difficult epidural placement was defined as more than 1 skin puncture with a Tuohy needle. Dura puncture occurrence was recorded. The population was randomly split into a training set and a validation set. In the training set, risk factors were identified with logistic regression and used to build a score defining 3 risk groups. Model and score discrimination was assessed with the C-index and clinical usefulness of the score with decision curves.
  
  
  RESULTS
  Difficult epidural placement frequency was 30% (95% confidence interval [95% CI], 25%-35%). Dural puncture was more frequent in DEP patients (4% vs 0%, P = 0.007). Three independent risk factors for DEP were identified: difficult interspinous space palpation (odds ratio [OR], 6.1; 95% CI, 2.8-13.9), spinal deformity (OR, 2.4; 95% CI, 1.1-5.3), and inability to flex the back (OR, 3.0; 95% CI, 1.2-7.8). The C-index of the model was 0.81 (95% CI, 0.74-0.88) in the training set and 0.78 (95% CI, 0.70-0.86) in the validation set. A 5-point score was created to define groups with low risk (score 0), intermediate risk (score 1-2), and high risk (score 3-4), with predicted rates of DEP of 9.7%, 30.3%, and 68.9%, respectively. The C-index of the score was 0.79 (95% CI, 0.72-0.86) in the training set and 0.76 (95% CI, 0.69-0.84) in the validation set. Decision curves support the clinical usefulness of the score.
  
  
  CONCLUSIONS
  This study confirms risk factors for DEP and proposes a score to predict DEP. The score identifies high-risk patients who may benefit from an intervention to decrease DEP. This hypothesis should be evaluated in an impact study.
authors.affiliation: Département d'Anesthésie-Réanimation, Hôpital Bichat, France. jean.guglielminotti@bch.aphp.fr
authors.forename: Jean
authors.initials: J
authors.lastname: Guglielminotti
authors.forename: France
authors.initials: F
authors.lastname: Mentré
authors.forename: Ennoufous
authors.initials: E
authors.lastname: Bedairia
authors.forename: Philippe
authors.initials: P
authors.lastname: Montravers
authors.forename: Dan
authors.initials: D
authors.lastname: Longrois
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural / Q000009:adverse effects* / Q000379:methods; D016362:Analgesia, Obstetrical / Q000009:adverse effects* / Q000379:methods; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors