Epidural Waveform Analysis for Thoracic Epidural Blocks
Condition: Surgical Procedure, Unspecified
Study type: Interventional

Summary: 
      Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for
      loss-of-resistance (LOR): when the needle/catheter tip is correctly positioned inside the
      epidural space, pressure measurement results in a pulsatile waveform. Epidural waveform
      analysis can be carried out through the tip of the needle or the catheter. In this randomized
      trial, the objective is to compare epidural waveform analysis through the needle (EWA-N) and
      through the catheter (EWA-C) for thoracic epidural blocks.
    

Detailed description: 
      The epidural space is most commonly identified with loss-of-resistance (LOR). Though
      sensitive Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for LOR.
      When the needle (or catheter) is correctly positioned inside the epidural space, pressure
      measurement at its tip results in a pulsatile waveform synchronized with arterial pulsations
      Currently, there exist two different methods for EWA. Since local anesthetic (LA) is
      administered through the catheter, pressure transduction through its tip ensures that it is
      properly positioned inside the epidural space prior to LA injection. Alternately, EWA can be
      performed through the needle prior to blind advancement of the epidural catheter.

      Thus, in this randomized trial, the aim is to compare epidural waveform analysis through the
      needle (EWA-N) and through the catheter (EWA-C) for thoracic epidural blocks. The hypothesis
      is that, compared to EWA-C, EWA-N will result in a shorter performance time.
    

Intervention name(s): EWA through the needle; EWA through the catheter
Intervention type(s): Device; Device
Intervention description(s): In the EWA-N group, 5 mL of normal saline are injected through the epidural needle after the occurrence of loss-of-resistance (LOR). The needle is connected to the pressure transducer. A satisfactory endpoint is defined as the presence of waveforms synchronized with arterial pulsations. In the absence of pulsatile waveforms, the operator injects an additional 2.5 mL-bolus of normal saline through the epidural needle and reconnects the latter to the pressure transducer. If no waveforms are detected after the second injection, the operator removes the needle and reattempts the epidural block at a different intervertebral level. A maximum of 3 levels is permitted: if waveforms are still absent at the third level, the operator simply accepts LOR as the technical endpoint.; In the EWA-C group, the epidural catheter is advanced 5 cm beyond the needle tip after the occurrence of LOR. Subsequently, the operator injects 5 mL of normal saline through the catheter and the latter is connected to the pressure transducer via the sterile, rigid extension tubing. A satisfactory endpoint is defined as the presence of waveforms. In the absence of pulsatile waveforms, the operator injects an additional 2.5 mL-bolus of saline through the catheter and reconnects the latter to the pressure transducer. If no waveforms are detected after the second injection are still absent at the third level, the operator simply accepts this position for catheter placement (intent-to-treat analysis).
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized trial
Masking: Single (Outcomes Assessor)
Primary purpose: Other
Keywords: Abdomen/surgery; Thoracic Surgery