Clinical trial NCT04553913: A Device to Determine Return of Sensation From Spinal Block
Official title: Proof-of-Concept: A Device to Determine Return of Sensation After a Regional Anesthetic Block
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Sensation Diminished, Pinprick
Keywords: nerve block
spinal block
local anesthetic
regional anesthesia
Lead sponsor: Wake Forest University Health Sciences
Sponsor class: OTHER
First posted: 2020-09-18
Enrollment: 15
Sex: ALL
Minimum age (years): 18
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Intervention model description: All participants will have the device placed in the recovery room to determine resolution of regional anesthetics.
Primary purpose: TREATMENT

Brief summary: Participation in this study will involve having a pad wrapped onto the subject's non-surgical leg to detect when sensation returns after spinal anesthetic and while in recovery room. The pad is part of an approved medical device, but which has been modified and will be used in an experimental way. The device will run cold water through the pad wrapped to the subject's leg. The subject will be asked to press a stop button when they feel the pad gets cold. Nurses in the recovery area will also be testing return of sensation using a standard technique and this will be compared to when the subject begins to feel the cold.

Detailed description: Regional anesthesia investigators have always shown interest in measuring the specific duration of neuraxial or peripheral nerve blocks, and how variations in block technique or medications affect that duration. Although ostensibly a simple concept, there are many sensory modalities available for block testing (light touch, cold or hot temperature, pain, pressure, etc.) and there is no consensus in the anesthesia literature on how best to measure the duration of nerve block (. Sensory testing is repetitive, and must be practical and consistent. Pinprick and cold sensation are commonly employed, and these modalities share the same afferent fibers (C-delta) so there is close overlap in the sensory loss mapping after regional block. With respect to pinprick sensation there can be variability in the sharpness, pressure, and reproducibility of a pinprick test. Testing for cold sensation may be more consistent, using a controlled stimulus temperature and duration, and there are different methods of testing such as a cooled glass vial (5℃) or Rolltemp (25℃).

Testing for long-acting blocks overnight adds an additional challenge since it requires repetitive subject awakening for assessment, and the interval for testing is a compromise between test specificity and sleep disruption. Again, there is no consensus on the proper interval for testing recovery from regional block.

Cold therapy is a commonly applied modality following strenuous exercise or during recovery from extremity surgery, and is expected to reduce tissue damage and relieve pain. There is some evidence of benefit but little consensus on the optimum interval and duration of therapy, and there are many approved medical devices available for use.

This investigation proposes an adaptation of an approved cold therapy device to administer automated, periodic cold stimulus at a location made insensate by regional block. When the subject perceives cold at that site, they will press a stop switch to discontinue cooling which will also stop a timer and give an accurate duration of the time to recovery of sensation at that site.

The concept will be tested by comparing the duration measured to the standard measurement of recovery from nerve block (spinal) employed by post-anesthesia care unit (PACU) nurses who will use pinprick (toothpick) testing of lumbar dermatomes every thirty minutes. If the device shows acceptable agreement with standard block recovery testing, a follow-up study would be its evaluation for long-duration block testing as an alternative to research assistant repeated testing overnight.

Eligibility criteria: Inclusion Criteria:

* Patients 18-75 y/o and scheduled to undergo unilateral primary knee or hip arthroplasty under spinal anesthesia with bupivacaine, ropivacaine or tetracaine will be eligible.

Exclusion Criteria:

* Patients will be excluded if pre-block sensation is abnormal in the L3 dermatome of the non-operative leg (neuropathy), or if spinal anesthesia is not performed or is unsuccessful.
* They will also be excluded if sensation has already returned in the L3 dermatome on arrival to the PACU.

Primary outcomes:
measure: Block Recovery Time (Device)
timeFrame: Baseline, from injection and up to 4 hours after injection
measure: Block Recovery Time (Pinprick Test)
timeFrame: Baseline, from injection and up to 4 hours after injection
Secondary outcomes:
measure: Device Temperature Consistency
timeFrame: 2 hours after baseline
measure: Cooling Pad Temperature (°F) at Stop Switch Activation
timeFrame: 2 hours after baseline
Other outcomes:
Locations:
city: Winston-Salem
country: United States
facility: Wake Forest School of Medicine
state: North Carolina
Study officials:
affiliation: Wake Forest University Health Sciences
name: Seiha Kim, DO
role: PRINCIPAL_INVESTIGATOR
References: