Anterior quadratus lumborum catheters for elective cesarean section: A double-blind, randomized, placebo-controlled trial.

BACKGROUND: Optimizing pain management following cesarean section is crucial for the well-being of both mother and infant. Various types of quadratus lumborum blocks have exhibited reduced opioid consumption and pain scores after cesarean section. However, duration of block effect is relatively short. The aim of this study was to investigate the analgesic efficacy of the anterior quadratus lumborum catheters for cesarean section. METHODS: All 32 enrolled participants were allocated to postoperative bilateral ultrasound-guided anterior quadratus lumborum catheter placement with injection of 60 mL ropivacaine 0.375% after cesarean section. Randomization at 2 h resulted in either 60 mL ropivacaine 0.2% or 60 mL isotonic saline injected through the catheters, with subsequent 22-h infusion of either ropivacaine 0.2% or isotonic saline with an infusion rate of 4 mL h-1 per catheter. Participants in the active group received a total of 697 mg ropivacaine during the first 24 h. All participants received the standard postoperative multimodal pain regimen, and a final bilateral injection at 24-h post-catheter placement of 60 mL ropivacaine 0.375% in total. The primary outcome was time to first opioid administration. Secondary outcomes were pain scores, time to first ambulation, nausea and vomiting, accumulated opioid consumption, and catheter displacement rates. RESULTS: No significant intergroup differences were observed following the randomized intervention. Median time to first opioid (IQR) was (active vs. placebo) 414 (283, 597) vs. 428 (245, 552) minutes, with a median difference (CI) of -14 (-184 to 262) min, p = .32. CONCLUSION: Bilateral anterior quadratus lumborum catheters with continuous infusion did not prolong time to first opioid after elective cesarean section.

The intertransverse process block single- or multiple-injection? A study protocol.

BACKGROUND AND AIMS: Intertransverse process (ITP) blocks are applied on the posterior side of the thoracic paravertebral space. The modality is described as being a paravertebral block by proxy, possibly providing a similar analgesic effect as the thoracic paravertebral block. However, systematic evidence on anaesthetised dermatomes and the extent of cutaneous sensory loss following ITP blocks is sparse. This study aims to test the single- versus the multiple-injection ITP block. The primary outcome is the number of anaesthetised thoracic dermatomes for each block type. METHODS: Twelve healthy male volunteers will participate in this randomised, procedure-related, double-blinded, non-inferiority crossover trial after informed consent. Blinded participants will receive either a unilateral single-injection ITP block with 21 mL ropivacaine 7.5 mg/mL including two sham blocks or a unilateral multiple-injection ITP block with 3 × 7 mL ropivacaine 7.5 mg/mL on study Day 1, and the other modality on study Day 2. Block applicants will be blinded from outcome assessment and vice versa. Following block application sensory test by mechanical pinprick and temperature discrimination will be performed. Anterior truncal thermography will be measured three times after block application to compare skin temperature in the mid-clavicular line between the blocked and the contralateral non-blocked hemithorax. In addition, blood pressure changes are measured three times non-invasively. DISCUSSION: The current study will provide substantial knowledge regarding the cutaneous sensory loss of the ITP block. Furthermore, the study might provide insight regarding the possible clinical usage of thermography as a reliable instrument for measuring nerve block efficacy.

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy: Study protocol for a dose-finding trial.

BACKGROUND: The objective of this trial is to optimize the transmuscular quadratus lumborum (TQL) block, by investigating the minimal effective volume (MEV90 ) of ropivacaine 0.75% for single-shot TQL block in percutaneous nephrolithotomy (PNL) patients. METHODS: This double-blind, randomized and controlled dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anaesthetic administered to each patient depends on the response from the previous one. Investigating the TQL block, the first patient recruited receives 20 ml ropivacaine 0.75% preoperatively. In case of block failure, the next patient will receive the same volume with an increment of 2 ml. Given a successful block for the first patient, the next patient will be randomized to either a lower volume (previous volume with a reduction of 2 ml), or the same volume as the previous patient. The respective probabilities being b = 0.11 for a reduced volume and 1-b = 0.89 for the same volume. Block success is defined as patient reported pain score numeric rated scale (NRS) ≤3 (0-10/10) 30 minutes after arrival in the post anaesthesia care unit (PACU). The NRS pain score is our primary and only outcome for block success. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV90 with narrow 95% confidence intervals derived by bootstrapping. DISCUSSION: Recruiting will begin June 2020 and is expected to finish November 2020. Data analysis will be performed at interims during and after the study. Results will be published in an international peer-reviewed medical journal.

Are single-injection erector spinae plane block and multiple-injection costotransverse block equivalent to thoracic paravertebral block?

BACKGROUND: Thoracic paravertebral block (TPVB) is considered the gold standard for hemithoracic regional anaesthesia. Erector spinae plane block (ESPB) is a new posterior thoracic wall block. Multiple-injection costotransverse block (MICB) mimics TPVB but with injection points within the thoracic intertransverse tissue complex and posterior to the superior costotransverse ligament. We aimed to compare the spread of injectate into the thoracic paravertebral space (TPVS) resulting from single-injection ESPB and MICB, respectively, with TPVB. METHODS: Ten soft-embalmed cadavers were utilised. In five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided single-injection ESPB or single-injection TPVB; vice versa on the other side. In another five cadavers, the right hemithorax was randomly allocated either to ultrasound-guided MICB or multiple-injection TPVB. About 20 mL of dye was injected in each hemithorax with all techniques. RESULTS: With TPVB, the dye was consistently present in the TPVS with concomitant epidural spread in the majority of cases. The injectate spread into the TPVS with ESPB (60%) and MICB (100%). MICB consistently stained the ventral rami (T1-7), communicating rami and thoracic sympathetic trunk without epidural spread. Dissection after MICB revealed dye spread into the TPVS via the costotransverse foramina and along the dorsal branches of the posterior intercostal veins. CONCLUSIONS: Consistent spread of dye into the TPVS colouring the ventral rami, the communicating rami, and the sympathetic trunk was observed with MICB; in this respect equivalent to TPVB. ESPB exhibited only partial success and was not equivalent to TPVB. No epidural spread was found with neither MICB nor ESPB.

Superiority of ultrasound-guided Shamrock lumbar plexus block.

Ultrasound-guided lumbar plexus block (LPB) performed with the Shamrock approach has received much interest since the technique was first described in 2013. The technique is believed to be faster and easier to perform and possibly safer in regards to potential complications compared with other LPBs. In order to outline some favorable characteristics of the Shamrock LPB, we performed an exhaustive search of the current literature; even though it is rather limited. We have related the evidence to our own clinical experience about the block execution. We present a narrative review of the alleged superiority of the ultrasound-guided Shamrock LPB. Our aim was to assess some of the characteristics that we believe differentiate the Shamrock technique from other ultrasound-guided LPB techniques. We present graphical directions about how to carry out the Shamrock block, and we present novel magnetic resonance images illustrating the injectate spread around the lumbar plexus within the intrapsoas compartment after Shamrock guided injection of contrast enhanced local anesthetic. The Shamrock approach is easier, faster and better to visualise the LPB compared to other LPB techniques. The needle trajectory and needle tip location just lateral to the lumbar plexus probably reduces the risk of adverse effects and complications. Ultrasound guided lumbar plexus blockade is an expert technique. The Shamrock technique improves but does not eliminate all the challenges of ultrasound-guided LPB technique.