Surgical Procedure, Unspecified
Conditions
Keywords
Abdomen/surgery, Thoracic Surgery
Brief 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.
Interventions
DEVICEEWA through the needle
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.
DEVICEEWA through the catheter
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).
Sponsors
Ramathibodi Hospital
University of Chile
McGill University Health Centre/Research Institute of the McGill University Health Centre
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
SINGLE (Outcomes Assessor)
Masking description
The outcome assessment will not be present during the performance of the epidural block and waveform analysis.
Intervention model description
Randomized trial
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
* age between 18 and 80 years * American Society of Anesthesiologists classification 1-3 * body mass index between 20 and 35
Exclusion criteria
* adults who are unable to give their own consent * coagulopathy * renal failure * hepatic failure * allergy to local anesthetic * pregnancy * prior surgery in the thoracic spine
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Performance time of block | From skin infiltration until local anesthetic administration through the needle or catheter, up to 60 minutes | temporal interval in minutes between skin infiltration and local anesthetic administration through the epidural catheter (after obtaining a satisfactory waveform either through the needle or through the catheter depending on randomized group assignment). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Procedural pain during epidural block assessed by the numeric rating scale | From the performance of the epidural block until induction of general anesthesia, up to 2 hours | pain in the back of the patient, related to the performance of the epidural block, using a numeric rating scale from 0 to 10 points (0=no pain and 10= worst imaginable pain) |
| Postoperative pain related to surgical incision assessed by the numeric rating scale | twice a day from the arrival at PACU or until catheter removal, up to 5 days | pain at rest and upon deep breathing/coughing, measured using a numeric rating scale from 0 to 10 points ((0=no pain and 10= worst imaginable pain) |
| Incidence of successful epidural block | 15 minutes after the administration of local anesthetic through the epidural catheter | bilateral block to ice in at least 2 dermatomes |
| Breakthrough opioid consumption (if required) | once a day from the arrival at PACU or until catheter removal, up to 5 days | amount of opioids consumed |
| Incidence of adverse events | Once a day from catheter insertion until removal, up to 5 days | side effects related to the performance of the epidural block (eg, dural/vascular puncture, paresthesia) or breakthrough opioids (nausea, vomiting, pruritus, somnolence, respiratory depression) |
| Local anesthetic consumption | once a day from the arrival at PACU or until catheter removal, up to 5 days | amount of local anesthetic consumed |
Countries
Chile, Thailand
Outcome results
None listed