Continuous Nerve Block Block vs Combination of Single Block Plus Intravenous Lidocaine for Postoperative Pain.

After obtaining a signed informed consent, participating patients will be randomized by computer generated random numbers to either the control group to receive continuous Erector Spinae Plane block (in the case of thoracic surgery) or continuous Quadratus Lumborum block (in the case of abdominal surgery), or the treatment group to receive single shot Erector Spinae Plane block (in the case of thoracic surgery) or single shot Quadratus Lumborum block (in the case of abdominal surgery) with postoperative intravenous lidocaine infusion. Subjects will be randomized in a 1:1 ratio. Randomization will take place via an opaque envelope containing the treatment group allocation that will be given to the anesthesiologist performing the block after informed consent is signed. Procedures will take place in the UPMC Shadyside pre-operative block area. The expected duration of nerve block procedures is 10-20 minutes.

If the patient is randomized to the continuous nerve block group and is undergoing thoracic surgery, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach:

Continuous ESP Block Approach: The patient will be positioned in seated position with side or sides to be blocked marked. The T5 spinous process will be identified by palpation starting with C7 and continuing caudad. C7 is the most prominent spinous process anatomically. The T5 spinous process will be marked with a marking pen. The block area will be cleaned using 2% chlorhexidine solution. The entire block procedure is performed under strict aseptic technique. An ultrasound probe covered in a sterile probe cover will be placed at the T5 spinous process in a cephalad to caudad orientation and moved lateral until the T5 transverse process is identified. 1-2ml of 1% lidocaine will be administered just above the ultrasound probe for local skin infiltration. An 18 gauge Tuohy needle will then be inserted in plane in a cephalad to caudad direction under ultrasound visualization until the tip of the needle touches the T5 transverse process. The T5 transverse process is the anatomical target for this block. 20ml of 0.5% ropivacaine will then be injected using slow fractionated injection, aspirating every 5ml to ensure the needle tip is not intravascular. Local anesthetic spread in the appropriate plane will be confirmed with ultrasound. Once injection is complete, a 20 gauge nonstimulating catheter will be inserted through the Tuohy needle. Catheter tip placement will be confirmed with ultrasound. If bilateral blocks are to be performed, the procedure will then be repeated on the contralateral side. Upon patient arrival to PACU, a continuous infusion of 0.25% lidocaine at 10ml/hr per side blocked via ESP catheter will be initiated and continued for 72 hours or until 12 hours prior to patient discharge.

If the patient is randomized to the continuous nerve block group and is undergoing abdominal surgery, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach:

Continuous QL Block Approach: The patient will be positioned in lateral decubitus position with the side to be blocked facing up and the side or sides to be blocked marked. The block area will be cleaned using 2% chlorhexidine solution. The entire block procedure is performed under strict aseptic technique. An ultrasound probe covered in a sterile probe cover will be placed transversally between the iliac crest and the costal margin at the level of the anterior axillary line and the three muscles of the anterolateral abdominal wall (external oblique, internal oblique and transversus abdominis) will be identified. The probe will then be moved posteriorly until the transversus abdominis muscle (TAM) tapers off into its aponeurosis approximately at the level of the posterior axillary line, and posteriorly to this the intersection of the transversalis fascia with the lateral side of the QL muscle will be identified. An 18 gauge Tuohy needle will then be inserted in plane in an anterior to posterior direction until the tip of the needle is visualized at the intersection of the transversalis fascia with the lateral side of the QL muscle. The intersection of the transversalis fascia with the lateral side of the QL muscle is the anatomical target for this block. Once the initial injection of local anesthetic is complete, a 20 gauge nonstimulating catheter will be inserted through the Tuohy needle. Catheter tip placement will be confirmed with ultrasound. If bilateral blocks are to be performed, the patient will be repositioned, the area to be blocked will be cleaned and prepared in a strict aseptic fashion as described above, and the procedure will then be repeated on the contralateral side. Upon patient arrival to PACU, a continuous infusion of 0.25% Lidocaine at 10ml/hr per side blocked via QLB catheter will be initiated and continued for 72 hours or until 12 hours prior to patient discharge.

If the patient is randomized to the single block plus IV lidocaine group and is undergoing thoracic surgery, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach:

Single Shot ESP Block with Postoperative IV Lidocaine Approach: The same technique described for the CESP will be used except that in this case a single ESP block will be performed. A 22 gauge Tuohy needle will be used to perform these blocks. After the proper positioning of the needle 20ml of 0.5% ropivacaine plus, 4mg dexamethasone, plus 30mcg dexmedetomidine will be deposited. In the recovery room an infusion of IV lidocaine at 50mg/hr for be initiated for 72 hours or until 12 hours prior to patient discharge.

If the patient is randomized to the single block plus IV lidocaine group and is undergoing abdominal surgery, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach:

Single Shot QL Block with Postoperative IV Lidocaine Approach: The same technique described for the CQL will be used except that a single QL block will be performed. A 22 gauge Tuohy needle will be used to perform these blocks. After the proper positioning of the needle 20ml of 0.5% ropivacaine plus, 4mg dexamethasone, plus 20mcg dexmedetomidine per injection site (30mcg if unilateral block only) will be deposited. Upon patient arrival to PACU, a continuous infusion of intravenous lidocaine at 50mg/hr will be initiated and continued for 72 hours or until 12 hours prior to patient discharge.

Anesthetic Management: Both treatment groups will receive the standard anesthetic technique and multimodal analgesic technique at our institution, including preoperative gabapentin 300mg PO and acetaminophen 1000mg PO, intraoperative IV propofol infusion-based general anesthetic combined with sub-anesthetic dose IV ketamine infusion, IV dexmedetomidine infusion, IV acetaminophen, and avoidance of intraoperative opioids. Postoperative pain management will also follow standard protocol, using IV hydromorphone (0.2-0.3 mg) and PO oxycodone (5-10 mg) on request by the patient for moderate to severe pain (VAS >5), scheduled ketamine 20-50mg PO q 8hrs for 48 hours, scheduled acetaminophen 1000mg IV or PO q 6hrs, scheduled gabapentin 100-300mg PO at bedtime, and dexmedetomidine infusion 0.2mcg/kg/hr IV for 24 hours if the patient is located in the Intensive Care Unit.

After surgery, the patient will be followed by the blinded research team for incidence of adverse events, as well as the collection of the primary and secondary outcome measures. Pain assessment will be done by nurses in the PACU and on the floor using Numeric Pain Rating Scale, with 0 meaning no pain and 10 meaning worst possible pain. Opioid medication consumption, pain scores, local anesthetic medication consumption, serum lidocaine levels, and adverse effects will be recorded on worksheets included in patient research folders, with each study participant having their own research folder identified only by randomly assigned patient study number.

The research coordinator responsible for data collection will remain blinded to the patient's group allocation, and will not become unblinded during the data collection process because data will be collected from the patient's medical record and will not involve physically observing the patient (which would otherwise result in unblinding since the presence or absence of a perineural catheter and patient pump status would make the group allocation obvious). However, this information will not be obtainable when collecting data from the medical record. It is not possible to blind nursing staff or the patient to the patient's group allocation because the presence or absence of a visible perineural catheter will make the group allocation obvious.