Optimal techniques of ultrasound-guided superficial and deep parasternal intercostal plane blocks: a cadaveric study.

INTRODUCTION: The optimal techniques of a parasternal intercostal plane (PIP) block to cover the T2-T6 intercostal nerves have not been elucidated. This pilot cadaveric study aims to determine the optimal injection techniques that achieve a consistent dye spread over the second to sixth intercostal spaces after both ultrasound-guided superficial and deep PIP blocks. We also investigated the presence of the transversus thoracis muscle at the first to sixth intercostal spaces and its sonographic identification agreement, as well as the location of the internal thoracic artery in relation to the lateral border of the sternum. METHODS: Ultrasound-guided superficial or deep PIP blocks with single, double, or triple injections were applied in 24 hemithoraces (three hemithoraces per technique). A total volume of dye for all techniques was 20 mL. On dissection, dye distribution over the first to sixth intercostal spaces, the presence of the transversus thoracis muscle at each intercostal space and the distance of the internal thoracic artery from the lateral sternal border were recorded. RESULTS: The transversus thoracis muscles were consistently found at the second to sixth intercostal spaces, and the agreement between sonographic identification and the presence of the transversus thoracis muscles was >80% at the second to fifth intercostal spaces. The internal thoracic artery is located medial to the halfway between the sternal border and costochondral junction along the second to sixth intercostal spaces. Dye spread following the superficial PIP block was more localized than the deep PIP block. For both approaches, the more numbers of injections rendered a wider dye distribution. The numbers of stained intercostal spaces after superficial block at the second, fourth, and fifth intercostal spaces, and deep block at the third and fifth intercostal spaces were 5.3±1.2 and 5.7±0.6 levels, respectively. CONCLUSION: Triple injections at the second, fourth, and fifth intercostal spaces for the superficial approach and double injections at the third and fifth intercostal spaces for the deep approach were optimal techniques of the PIP blocks.

A comparison of the success rate of pneumatic reduction in intussusception between general anesthesia and deep sedation: a randomized controlled trial.

PURPOSE: This study was aimed to compare the success rate between patients who underwent general anesthesia and deep sedation. METHODS: Patients who were diagnosed with intussusception and had no contraindications would receive non-operative treatment first by undergoing pneumatic reduction. The patients were then split in to two groups: one group underwent general anesthesia (GA group), while the other underwent deep sedation (SD group). This study was a randomized controlled trial which compared success rate between two groups. RESULTS: A total of 49 episodes diagnosed with intussusception were random into 25 episodes in GA group and 24 episodes in SD group. There was no significant difference in baseline characteristic between the two groups. The success rates of GA group and SD group were equally 88.0% (p = 1.00). Sub-analysis of the success rate was lower in the patients with high-risk score for failed reduction. (Chiang Mai University Intussusception (CMUI) failed score in success VS failed = 6.9 ± 3.2 vs. 10.3 ± 3.0 p = 0.017). CONCLUSION: General anesthesia and deep sedation offered similar success rates. In cases of high risk of failure, general anesthesia should be considered to accommodate the switch to surgical management in the same setting if the non-operative approach fails. The appropriate treatment and sedative protocol also increase the success of reduction.

Efficacy of Phrenic Nerve Block and Suprascapular Nerve Block in Amelioration of Ipsilateral Shoulder Pain after Thoracic Surgery: A Systematic Review and Network Meta-Analysis.

Background and Objectives: Ipsilateral shoulder pain (ISP) is a common complication after thoracic surgery. Severe ISP can cause ineffective breathing and impair shoulder mobilization. Both phrenic nerve block (PNB) and suprascapular nerve block (SNB) are anesthetic interventions; however, it remains unclear which intervention is most effective. The purpose of this study was to compare the efficacy and safety of PNB and SNB for the prevention and reduction of the severity of ISP following thoracotomy or video-assisted thoracoscopic surgery. Materials and methods: Studies published in PubMed, Embase, Scopus, Web of Science, Ovid Medline, Google Scholar and the Cochrane Library without language restriction were reviewed from the publication's inception through 30 September 2022. Randomized controlled trials evaluating the comparative efficacy of PNB and SNB on ISP management were selected. A network meta-analysis was applied to estimate pooled risk ratios (RRs) and weighted mean difference (WMD) with 95% confidence intervals (CIs). Results: Of 381 records screened, eight studies were eligible. PNB was shown to significantly lower the risk of ISP during the 24 h period after surgery compared to placebo (RR 0.44, 95% CI 0.34 to 0.58) and SNB (RR 0.43, 95% CI 0.29 to 0.64). PNB significantly reduced the severity of ISP during the 24 h period after thoracic surgery (WMD -1.75, 95% CI -3.47 to -0.04), but these effects of PNB were not statistically significantly different from SNB. When compared to placebo, SNB did not significantly reduce the incidence or severity of ISP during the 24 h period after surgery. Conclusion: This study suggests that PNB ranks first for prevention and reduction of ISP severity during the first 24 h after thoracic surgery. SNB was considered the worst intervention for ISP management. No evidence indicated that PNB was associated with a significant impairment of postoperative ventilatory status.

The potential role of dexmedetomidine on neuroprotection and its possible mechanisms: Evidence from in vitro and in vivo studies.

Neurological disorders following brain injuries and neurodegeneration are on the rise worldwide and cause disability and suffering in patients. It is crucial to explore novel neuroprotectants. Dexmedetomidine, a selective α2-adrenoceptor agonist, is commonly used for anxiolysis, sedation and analgesia in clinical anaesthesia and critical care. Recent studies have shown that dexmedetomidine exerts protective effects on multiple organs. This review summarized and discussed the current neuroprotective effects of dexmedetomidine, as well as the underlying mechanisms. In preclinical studies, dexmedetomidine reduced neuronal injury and improved functional outcomes in several models, including hypoxia-induced neuronal injury, ischaemic-reperfusion injury, intracerebral haemorrhage, post-traumatic brain injury, anaesthetic-induced neuronal injury, substance-induced neuronal injury, neuroinflammation, epilepsy and neurodegeneration. Several mechanisms are associated with the neuroprotective function of dexmedetomidine, including neurotransmitter regulation, inflammatory response, oxidative stress, apoptotic pathway, autophagy, mitochondrial function and other cell signalling pathways. In summary, dexmedetomidine has the potential to be a novel neuroprotective agent for a wide range of neurological disorders.

Cadaveric study identifying clinical sonoanatomy for proximal and distal approaches of ultrasound-guided intercostobrachial nerve block.

BACKGROUND AND OBJECTIVES: The intercostobrachial nerve (ICBN) has significant anatomical variation. Localization of the ICBN requires an operator's skill. This cadaveric study aims to describe two simple ultrasound-guided plane blocks of the ICBN when it emerges at the chest wall (proximal approach) and passes through the axillary fossa (distal approach). METHODS: The anatomical relation of the ICBN and adjacent structures was investigated in six fresh cadavers. Thereafter, we described two potential techniques of the ICBN block. The proximal approach was an injection medial to the medial border of the serratus anterior muscle at the inferior border of the second rib. The distal approach was an injection on the surface of the latissimus dorsi muscle at 3-4 cm caudal to the axillary artery. The ultrasound-guided proximal and distal ICBN blocks were performed in seven hemithoraxes and axillary fossae. We recorded dye staining on the ICBN, its branches and clinically correlated structures. RESULTS: All ICBNs originated from the second intercostal nerve and 34.6% received a contribution from the first or third intercostal nerve. All ICBNs gave off axillary branches in the axillary fossa and ran towards the posteromedial aspect of the arm. Following the proximal ICBN block, dye stained on 90% of all ICBN's origins. After the distal ICBN block, all terminal branches and 43% of the axillary branches of the ICBN were stained. CONCLUSIONS: The proximal and distal ICBN blocks, using easily recognized sonoanatomical landmarks, provided consistent dye spread to the ICBN. We encourage further validation of these two techniques in clinical studies.

A Comparison of the external anatomical landmark and the radiological landmark for obtaining the optimal depth of a right internal jugular venous catheter in pediatric cardiac patients.

BACKGROUND: The external anatomical landmark and the radiological landmark have been introduced to provide estimation of the depth of right internal jugular venous catheter during insertion. AIMS: This study aimed to compare the accuracy, agreement, and reliability of the external anatomical landmark and the radiological landmark, confirmation being by transesophageal echocardiography. METHODS: This prospective observational study was conducted in children ages 1-15 years. The catheter was placed at the superior vena cava and the right atrium junction guided by transesophageal echocardiography. The catheter depth derived from the transesophageal echocardiography, the external anatomical landmark, and the radiological landmark was recorded. The optimal zone of the catheter tip was 5 mm below and 10 mm above the superior vena cava and the right atrium junction. Accuracy was assessed by the difference between the transesophageal echocardiography and the external anatomical landmark or the radiological landmark. Agreement with Bland-Altman plots and correlation were tested. RESULTS: Eighty participants, median age of 3 years, were enrolled. The median (IQR) differences between the depth of the transesophageal echocardiography and the external anatomical landmark or the radiological landmark were 0.30 (0, 0.70) and 0.10 (-0.20, 0.90) cm, respectively. Bland-Altman plots demonstrated good agreement between the depths. The catheter tips were located in the optimal zone more frequently with the external anatomical landmark than the radiological landmark (94.7% vs 64.5%). The external anatomical landmark showed a stronger correlation to transesophageal echocardiography than the radiological landmark (r = .95 vs .83). CONCLUSION: Both the external anatomical landmark and the radiological landmark enabled accurate estimation of the central venous catheter depth close to the superior vena cava and the right atrium junction. The external anatomical landmark is of more potential use than the radiological landmark in clinical practice.

A Prospective, randomized comparative study between ultrasound-guided posterior quadratus lumborum block and ultrasound-guided ilioinguinal/iliohypogastric nerve block for pediatric inguinal herniotomy.

BACKGROUND: Ilioinguinal/iliohypogastric nerve block is commonly performed to control postherniotomy pain. The posterior quadratus lumborum block has been recently described as an effective analgesic technique for pediatric low abdominal surgery. No data were found regarding the use of posterior quadratus lumborum block in comparison with the traditional ilioinguinal/iliohypogastric nerve block in pediatric inguinal surgery. AIM: This randomized assessor-blinded study compared postoperative analgesic effects between ultrasound-guided posterior quadratus lumborum block and ilioinguinal/iliohypogastric nerve block in pediatric inguinal herniotomy. METHODS: One- to seven-year-old children scheduled for unilateral open herniotomy were randomly assigned to receive either ultrasound-guided posterior quadratus lumborum block with 0.25% bupivacaine 0.5 mL/kg or ultrasound-guided ilioinguinal/iliohypogastric nerve block with 0.25% bupivacaine 0.2 mL/kg after induction of general anesthesia. The primary outcome was the proportion of patients who received postoperative oral acetaminophen. The required fentanyl in the recovery room, 24-hour acetaminophen consumption, success rate of regional blocks, block performance data, block-related complications, postoperative pain intensity, and parental satisfaction were assessed. RESULTS: This study included 40 patients after excluding four cases who were ineligible. The number of patients who required postoperative oral acetaminophen was significantly lower in the posterior quadratus lumborum block group (15.8% vs 52.6%; OR: 5.9; 95% CI: 1.3, 27.3; P = .022). The pain scores at 30 minutes, 1, 2, 6, 12, and 24 hours were similar between groups. There was no evidence of between-group differences in block performance time, the number of needle passes, block-related complications, and parental satisfaction. CONCLUSION: The posterior quadratus lumborum block with 0.25% bupivacaine 0.5 mL/kg provided better pain control than the ilioinguinal/iliohypogastric nerve block with 0.25% bupivacaine 0.2 mL/kg after open herniotomy in children. The ultrasound guidance technique for the posterior quadratus lumborum block is safe and as simple as the ultrasound-guided ilioinguinal/iliohypogastric nerve block for pediatric patients.

A multicenter, randomized comparison between 2, 5, and 8 mg of perineural dexamethasone for ultrasound-guided infraclavicular block.

BACKGROUND AND OBJECTIVES: This multicenter, randomized trial compared 2, 5, and 8 mg of perineural dexamethasone for ultrasound-guided infraclavicular brachial plexus block. Our research hypothesis was that all three doses of dexamethasone would result in equivalent durations of motor block (equivalence margin=3.0 hours). METHODS: Three hundred and sixty patients undergoing upper limb surgery with ultrasound-guided infraclavicular block were randomly allocated to receive 2, 5, or 8 mg of preservative-free perineural dexamethasone. The local anesthetic agent (35 mL of lidocaine 1%-bupivacaine 0.25% with epinephrine 5 µg/mL) was identical in all subjects. Patients and operators were blinded to the dose of dexamethasone. During the performance of the block, the performance time, number of needle passes, procedural pain, and complications (vascular puncture, paresthesia) were recorded. Subsequently a blinded observer assessed the success rate (defined as a minimal sensorimotor composite score of 14 out of 16 points at 30 min), onset time as well as the incidence of surgical anesthesia (defined as the ability to complete surgery without local infiltration, supplemental blocks, intravenous opioids, or general anesthesia). Postoperatively, the blinded observer contacted patients with successful blocks to inquire about the duration of motor block, sensory block, and postoperative analgesia. The main outcome variable was the duration of motor block. RESULTS: No intergroup differences were observed in terms of technical execution (performance time/number of needle passes/procedural pain complications), onset time, success rate, and surgical anesthesia. Furthermore, all three doses of dexamethasone provided similar durations of motor block (14.9-16.1 hours) and sensory block. Although 5 mg provided a longer analgesic duration than 2 mg, the difference (2.7 hours) fell within our pre-established equivalence margin (3.0 hours). CONCLUSIONS: 2, 5, and 8 mg of dexamethasone provide clinically equivalent sensorimotor and analgesic durations for ultrasound-guided infraclavicular block. Further trials are required to compare low (ie, 2 mg) and ultra-low (eg, 0.5-1 mg) doses of perineural dexamethasone for brachial plexus blocks. TRIAL REGISTRATION NUMBER: TCTR20150624001.

A Comparison of Pediatric Weight Estimation Methods for Emergency Resuscitation.

OBJECTIVES: Obtaining accurate pediatric weight is necessary during emergency resuscitation. Although several weight estimation methods exist, the most precise method has not been conclusively determined. This study aimed to evaluate the validity, reliability, and practicality of these tools. METHODS: A prospective observational study was conducted in healthy Thai children aged 6 months to 12 years. Correlations between estimated and actual weights were tested. Validity was assessed by mean bias (estimated weight minus actual weight) and accuracy (10% error). Practicality was evaluated by time usage and data derived from user questionnaires. RESULTS: Four hundred thirty participants with mean age of 6.7 years and mean weight of 26 kg were enrolled. A strong correlation between estimated weight and actual weight in all methods was demonstrated. Parental estimation was the most accurate tool in all age groups, with the lowest overall mean error (ME) of -0.83 kg and the highest accuracy of 88.7%. The Broselow tape was the second most accurate tool in ages younger than 1 year and 1-to-5-year age groups (ME = 0.23 and 0.50 kg; accuracy = 55.3% and 54.1%, respectively). The Mercy method was the second most accurate tool in the 6-to-10-year and 11-to-12-year age groups (ME = -2.47 and -2.77; accuracy = 54.6% and 67.9%, respectively). The Broselow tape had the highest score for practicality of use. CONCLUSIONS: Parental estimation was the most accurate method in every age group. The next best alternative is the Broselow tape in children aged 5 years or younger and the Mercy method in children aged older than 5 years.

Minimum Effective Volume of Lidocaine for Ultrasound-Guided Costoclavicular Block.

BACKGROUND AND OBJECTIVES: This dose-finding study aimed to determine the minimum effective volume in 90% of patients (MEV90) of lidocaine 1.5% with epinephrine 5 µg/mL for ultrasound-guided costoclavicular block. METHODS: Using an in-plane technique and a lateral-to-medial direction, the block needle was positioned in the middle of the 3 cords of the brachial plexus in the costoclavicular space. The entire volume of lidocaine was deposited in this location. Dose assignment was carried out using a biased-coin-design up-and-down sequential method, where the total volume of local anesthetic administered to each patient depended on the response of the previous one. In case of failure, the next subject received a higher volume (defined as the previous volume with an increment of 2.5 mL). If the previous patient had a successful block, the next subject was randomized to a lower volume (defined as the previous volume with a decrement of 2.5 mL), with a probability of b = 0.11, or the same volume, with a probability of 1 - b = 0.89. Success was defined, at 30 minutes, as a minimal score of 14 of 16 points using a sensorimotor composite scale. Patients undergoing surgery of the elbow, forearm, wrist, or hand were prospectively enrolled until 45 successful blocks were obtained. This clinical trial was registered with ClinicalTrials.gov (ID NCT02932670). RESULTS: Fifty-seven patients were included in the study. Using isotonic regression and bootstrap confidence interval, the MEV90 for ultrasound-guided costoclavicular block was estimated to be 34.0 mL (95% confidence interval, 33.4-34.4 mL). All patients with a minimal composite score of 14 points at 30 minutes achieved surgical anesthesia intraoperatively. CONCLUSIONS: For ultrasound-guided costoclavicular block, the MEV90 of lidocaine 1.5% with epinephrine 5 µg/mL is 34 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and multiple-injection techniques.

A randomized comparison between costoclavicular and paracoracoid ultrasound-guided infraclavicular block for upper limb surgery.

BACKGROUND: This two-centre randomized trial compared costoclavicular and paracoracoid ultrasound-guided infraclavicular brachial plexus block in patients undergoing upper limb surgery. We hypothesized that both techniques would result in similar onset times and designed the study as an equivalence trial. METHODS: Ninety patients undergoing upper limb surgery at or distal to the elbow were randomly allocated to receive a costoclavicular (n = 45) or paracoracoid (n = 45) ultrasound-guided infraclavicular brachial plexus block. Both groups received a 35-mL mixture of 1% lidocaine-0.25% bupivacaine with epinephrine 5 µg·mL-1. In the costoclavicular group, local anesthetic was injected into the costoclavicular space in the middle of the three cords of the brachial plexus. In the paracoracoid group, local anesthetic was deposited dorsal to the axillary artery in the lateral infraclavicular fossa. A blinded observer recorded the block onset time (primary endpoint), success rate (i.e., surgical anesthesia), block-related pain scores, as well as the incidence of hemidiaphragmatic paralysis. Performance time and the number of needle passes were also recorded during the performance of the block. The total anesthesia-related time was defined as the sum of the performance and onset times. RESULTS: The mean (SD) onset times were comparable between the costoclavicular and paracoracoid groups [16.0 (7.5) min vs 16.8 (6.2) min, respectively; mean difference, 0.8; 95% confidence interval, -2.3 to 3.8; P = 0.61]. Furthermore, no intergroup differences were found in terms of performance time (P = 0.09), total anesthesia-related time (P = 0.90), surgical anesthesia (P > 0.99), and hemidiaphragmatic paralysis (P > 0.99). The paracoracoid technique required marginally fewer median [interquartile range] needle passes than the costoclavicular technique (2 [1-4] vs 2 [1-6], respectively; P = 0.048); however, procedural pain was comparable between the two study groups. CONCLUSION: Costoclavicular and paracoracoid ultrasound-guided infraclavicular blocks resulted in similar onset times. Furthermore, no intergroup differences were found in terms of performance times and success rates. Future dose-finding trials are required to elucidate the minimum effective volume of local anesthetic for costoclavicular infraclavicular blocks. This trial was registered at www.clinicaltrials.in.th (Study ID: TCTR20160525001).