ED90 of 3% Chloroprocaine for Cervical Cerclage
Condition: Cerclage, Cervical
Intervention: Chloroprocaine Hcl 3% Inj
Intervention description: Initial Patient (A#X) 45mg (1.5mL) of Chloroprocaine 3% (Nesacaine - Fresenius Kabi), will be drawn up into a 3 ml syringe (a 1 ml 'TB syringe' will be used to aspirate the drug in aliquots to ensure accuracy). The following additive will be added: 10 mcg (0.2ml) of fentanyl (50 mcg/ml) 0.3 ml of sterile 0.9% sodium chloride Thus the total volume in the syringe will be 2 ml. Study drugs will be prepared by one anesthesiologist (un-blinded) and administered by another anesthesiologist (blinded).
Subsequent Patient (A#X+1) The dose of Chloroprocaine 3% based on outcome from prior subject and calculations mentioned previously will be added to 10 mcg (0.2ml) of fentanyl (50 mcg/ml). Sterile 0.9% sodium chloride will be added until the total volume in the syringe is 2 ml.
Intervention MeSH terms: Chloroprocaine
Phase: Phase 4
Study type: Interventional
Primary purpose: Diagnostic
Intervention model: Sequential Assignment
Intervention model description: Initial Patient (A#X) 45mg (1.5mL) of Chloroprocaine 3% (Nesacaine - Fresenius Kabi), will be drawn up into a 3 ml syringe (a 1 ml 'TB syringe' will be used to aspirate the drug in aliquots to ensure accuracy). The following additive will be added: 10 mcg (0.2ml) of fentanyl (50 mcg/ml) 0.3 ml of sterile 0.9% sodium chloride Thus the total volume in the syringe will be 2 ml. Study drugs will be prepared by one anesthesiologist (un-blinded) and administered by another anesthesiologist (blinded).
Subsequent Patient (A#X+1) The dose of Chloroprocaine 3% based on outcome from prior subject and calculations mentioned previously will be added to 10 mcg (0.2ml) of fentanyl (50 mcg/ml). Sterile 0.9% sodium chloride will be added until the total volume in the syringe is 2 ml.
Masking: None (Open Label)
Masking description: The solutions and their administration procedures are identical to those used outside this research and are almost exclusively used for patients requiring spinal anesthesia for cervical cerclage. The only deviation involves diluting the chloroprocaine with saline so that study solutions are of equal volume to maintain blinding.
Enrollment: 47.0
Sex: Female
Minimum age: 18 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      The aim of this study is to identify the dose of intrathecal (IT) chloroprocaine that
      provides effective anesthesia in 90% of patients undergoing elective cerclage placement
      (intraoperative analgesic supplementation not required).
    

Eligibility criteria:

        Inclusion Criteria:

          -  ≥ 18 years of age

          -  Singleton pregnancy

          -  ASA class II or III

          -  Cervical cerclage 1st or 2nd trimester of pregnancy

          -  Simple prophylactic cervical cerclage

        Exclusion Criteria:

          -  Patient refusal

          -  Abdominal and complex cervical cerclage (e.g. bulging bag)

          -  BMI ≥ 50 kg/m2

          -  ASA class IV or above

          -  Contraindication to neuraxial anesthesia

          -  Allergy to chloroprocaine