Air Versus Saline Solution for the Localization of the Epidural Space in Labour Analgesia
Condition: Effects of Anesthesia Spinal and Epidural in Pregnancy
Study type: Interventional

Summary: 
      Epidural space localization using loss of resistance technique with air (ALOR) is
      controversial in obstetric analgesia due to a minor efficacy and risk of complications,
      compared with loss of resistance technique with saline (SLOR). This randomized prospective
      study will compare the efficacy and incidence of most common complications of both techniques
      in obstetric analgesia.
    

Detailed description: 
      A local ethics committee has approved the study. A statistical power calculation was
      performed and 177 patients per group will be necessary to confirm a 20% difference of
      efficacy of the block at 30 minutes (α=0,05; β=0,1). Epidural catheter will be inserted and a
      standardized analgesic protocol will initiate. The efficacy of the block will be assessed
      after 30 minutes and at delivery. The apparition of adverse effects during puncture and
      labour will be annotated. The need for repuncture of the block and the repercussion of the
      technique on the delivery and the fetus will be recorded as well. At 24 hours, investigators
      will assess the incidence of pain at the site of puncture (PSP) and the level of maternal
      satisfaction on a 0 to10 numeric scale.
    

Intervention name(s): air in epidural space; saline in epidural space
Intervention type(s): Procedure; Procedure
Intervention description(s): The epidural puncture will be performed in the L3-L4 or L4-L5 interspinous space in a seated position. A local anaesthesia with 2-5 mL of 2% lidocaine will be applied subcutaneously using a 25Gm 25mm needle. The epidural space will be localized using a Perifix® set by inserting the Tuohy needle in the ligamentum flavum or the interspinous space. The obturator will be then withdrawn and the low resistance syringe filled with 3-5mL of air will be connected. After localizing the epidural space, the catheter will be inserted 3-5 cm. An aspiration test will be performed through the catheter in a decline position with a 2 mL syringe, and a 3mL test dose with bupivacaine 0,25% plus epinephrine 1/200.000 will be administered to exclude an intradural or an intravascular position of the catheter.; The epidural puncture will be performed in the L3-L4 or L4-L5 interspinous space in a seated position. A local anaesthesia with 2-5 mL of 2% lidocaine will be applied subcutaneously using a 25Gm 25mm needle. The epidural space will be localized using a Perifix® set by inserting the Tuohy needle in the ligamentum flavum or the interspinous space. The obturator will be withdrawn and the low resistance syringe filled with 3-5mL of saline solution will be connected. After localizing the epidural space, the catheter will be inserted 3-5 cm. An aspiration test will be performed through the catheter in a decline position with a 2 mL syringe, and a 3mL test dose with bupivacaine 0,25% plus epinephrine 1/200.000 will be administered to exclude an intradural or an intravascular position of the catheter.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)