Perfusion Index as an Early Predictor of Successful Supraclavicular Block Clinical Trial
Official title:
Evaluation of the Ability of Perfusion Index in Detection of Ulnar Nerve Sparing During Ultra Sound Guided Supraclavicular Block
The aim of this study to evaluate the ability of perfusion index to detect ulnar sparing and to estimate the proper time for the perfusion index ratio to determine successful block.
On arrival to the operating room, patients will be connected to standard continuous
monitoring; i.e. 5 lead electrocardiography (ECG), pulse oximetry, and automated non-invasive
blood pressure monitoring (NIBP) every 5 minute. Two radical-7 (masimo set) devices will be
connected the patient through two probes. The probes will be connected to both index and
fifth digit to have a baseline reading before block performance. After block performance, PI
will be continuously monitored for 30 minutes.
2-Anesthetic technique
Supraclavicular block:
Equipment and preparation:
- Ultrasound machine with linear transducer (8-14 MHz) (Siemens acusonx300, Korea).
- 5-cm, 22-gauge insulated block needle
- Sterile gloves, sterile sleeve, and gel (Or other coupling medium; e.g. Saline)
- 20 to 25 ml of 0.5% bupivacaine + 2% lidocaine in equal volumes
Patient position:
The block can be performed while the patient is in the supine, semi-sitting, with the
Patient's head turned away from the side to be blocked with slight elevation of the head of
the bed which is often more comfortable for the Patient and allows for better drainage and
less prominence of the neck veins.
Technique:
After sterilization and local anaesthetic infiltration of skin, the linear transducer will be
applied firmly above the clavicle in the coronal oblique plane to view the transverse section
of the subclavian artery, pleura, first rib and brachial plexus (which is recognized as
around or oval compact groups of hypo-echoic nerves, located lateral and superficial to the
pulsatile subclavian artery and superior to the first rib). The 22-gauge needle will be
inserted at the lateral side of the ultrasound probe using In-plane approach. The block
needle will be advanced along the long axis of the transducer (from lateral to medial). The
needle will be advanced towards the target nerves inferior, lateral and superficial to
subclavian artery respectively. Local anesthetic solution is injected so as to cause hydro
dissection of the planes around the plexus the volume of local Anesthetic used is usually
between 20 to 25 ml.
Motor block will be assessed as inability to flex elbow and hand joints against gravity and
will be tested for each nerve as follow Radial nerve = Push the arm by extending the forearm
at the elbow against the resistance, musculocutaneous nerve = Resisting the pull of the
forearm at the elbow, median nerve = Thumb and second digit pinch, ulnar nerve = Thumb and
fifth digit pinch (15). Sensory block will be assessed by using piece of ice in the
distribution of median, ulnar, radial and musculocutaneous nerves. This assessment will take
place every 5 minutes till 30 minutes and the block will be considered failed if the patient
reports pain at the examined dermatomes during assessment time which needs conversion to
general anesthesia. If the patient reports no sensation in the whole upper limb apart from
the dermatomes supplied by ulnar nerve, which is not relieved after local infiltration of
skin by local anesthetic this will be considered ulnar nerve sparing.
The block assessment will be correlated with Masimo pulse oximetry readings during the first
30 minutes of the block.
Masimo reading of PI values will be recorded every minute (at both index and fifth digits)
for 10 minutes then every 3 minutes for 7 readings.
Monitoring of HR, MAP and pulse oximetry will be recorded before the block and every 5
minutes for 30 minutes after the block, then every 15 minutes till the end of surgery.
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