Serratus Anterior Plane Block and Intercostal Nerve Block after Thoracoscopic Surgery.

BACKGROUND: This study aimed to compare the postoperative analgesic effect between ultrasound-guided serratus anterior plane block (Group S, SAPB) and intercostal nerve block (Group I, ICNB) after single port video-assisted thoracoscopic surgery (S-VATS) in primary spontaneous pneumothorax. METHODS: In this prospective randomized controlled study, 54 patients were randomly assigned to two groups. Patients in Group S underwent the SAPB before the surgical drape by an anesthesiologist, and in Group I, ICNBs were performed just before the wound closure after S-VATS by an attending thoracic surgeon. The primary outcome was the numeric pain rating scale (NRS) score given by the patients for pain at the surgical incision site. NRS was assessed during resting and coughing statuses at 3, 6, and 12 hours postoperatively and at the time of the chest tube removal. The secondary outcomes included the number of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid administration until time to chest tube removal. RESULTS: There were no statistical differences between the two groups regarding age, body mass index, duration of operation, duration of anesthesia, and average NRS scores for the assigned time periods. There was no statistical significance in the number of opioid injections; however, NSAIDs were administered 2.8 times per patient in Group I, and 1.9 times per patient in Group S (p = 0.038). CONCLUSION: In the patients who underwent S-VATS with primary spontaneous pneumothorax, the SAPB provided similar postoperative pain relief with reducing the NSAIDs consumption compared with ICNB.

The Effect of Continuous Field Block through Intercostal Muscles after Atrial Septal Defect Closure via a Mini-Right Thoracotomy in Pediatric Patients.

BACKGROUND: Postoperative pain management in thoracotomy patients often is difficult. Furthermore, pediatric patients present more challenges because of their inability to effectively communicate their pain intensity. The purpose of this study was to evaluate the use of continuous field block through intercostal muscles as postoperative pain management in pediatric thoracotomy. METHODS: Between 2014 and 2018, 11 patients underwent an ASD closure using a cardiopulmonary bypass via a mini-right thoracotomy through the fourth intercostal space. At the time of chest closure, a single-shot field block via the fourth intercostal muscles was performed with levobupivacaine (0.6 mg/kg). The first five patients were only given the single-shot field block (Single group). The remaining six patients were given levobupivacaine continuously (0.1 mg/kg/hr) through an indwelling catheter until the chest tube removal (Continuous group). The groups' vital signs, total amounts of acetaminophen used, postoperative courses were compared. RESULTS: Although the heart rate did not differ between the groups, the respiratory rate was significantly higher in the Single group versus the Continuous group at 16 and 32 hr post-surgery (35.6 ± 9.7/min vs. 18.5 ± 4.7/min; p=0.007, 43.0 ± 10.4 vs. 25.3 ± 3.1; p=0.042, respectively). The accumulated dosage of acetaminophen given by postoperative day 2 was significantly higher in the Single group versus the Continuous group (55.3 ± 22.1 mg/kg vs. 7.8 ± 17.4 mg/kg; p=0.012). CONCLUSIONS: Continuous field block via intercostal muscles after ASD closure via a mini-right thoracotomy in children was effective to stabilize the vital signs and reduce the analgesic medication use.

Postoperative Thoracic Pain Treatment: Serratus Anterior or Erector Spinae Plane Block?

BACKGROUND: Thoracic surgery is one of the most painful surgeries. Effective analgesia is important in postoperative pain management. In this study, we aimed to compare the two new fascial block techniques. METHODS: A total of 107 patients who underwent thoracic surgery between October 2018 and November 2019 were retrospectively evaluated. The study included 59 patients in the serratus anterior plane block (SAPB) group and 48 patients in the erector spinae plane block (ESPB) group. Both groups were administered 30 mL of 0.25% bupivacaine and their morphine consumption was evaluated by a patient-controlled analgesia (PCA) method during the 2nd, 6th, 12th, 24th, and 48th postoperative hours. Pain was measured with the visual analog scale (VAS). Intraoperative mean arterial pressure (MAP) and heart rate (HR) were recorded. RESULTS: During the first 24 hours, VAS values were significantly lower in the ESPB group (p < 0.05). Moreover, morphine consumption was significantly lower in the ESPB group in the 24th and 48th hours (p < 0.05). Intraoperative remifentanil consumption was also significantly lower in the ESPB group (p < 0.05). Intraoperative MAP in the ESPB group was found to be significantly lower after the 4th hour. HR was similar in both groups. CONCLUSION: ESPB was more effective compared with SAPB in postoperative thoracic pain management.

Evaluation of postoperative pain in patients undergoing modified radical mastectomy with pectoralis or serratus-intercostal fascial plane blocks.

BACKGROUND: Regional nerve blocks are an integral part of multimodal analgesia and should be chosen based on their efficacy, convenience, and minimal side effects. Here, we compare the use of pectoral (PEC II) and serratus-intercostal fascial plane (SIFP) blocks in breast carcinoma cases undergoing modified radical mastectomy (MRM) in terms of the postoperative analgesic efficacy and shoulder mobility. METHODS: The primary outcome of this prospective controlled study was to compare the postoperative static and dynamic pain scores, and the secondary outcome was to assess the shoulder pain, range of shoulder joint motion, and hemodynamic parameters. Sixty patients were randomly allocated to three groups and given general anesthesia. All patients received paracetamol, diclofenac, and rescue doses of tramadol based on the Institute's Acute Pain Service (APS) policy. No block was performed in group C (control), whereas groups P and S received PEC II and SIFP blocks, respectively, before surgical incision. RESULTS: The groups were comparable in terms of age, weight, height, and body mass index distribution (P > 0.05). Dynamic pain relief was significantly better 12 and 24 h postoperatively in groups P (P = 0.034 and P = 0.04, respectively) and S (P = 0.01 and P = 0.02, respectively) compared to group C. Shoulder pain relief and shoulder mobility were better in group S, while the hemodynamic parameters were more stable in group P. CONCLUSIONS: Both SIFP and PEC blocks have comparable dynamic and static pain relief with better shoulder pain scores in patients receiving SIFP.

BRILMA block for costal cartilage excision: Case report. / Bloqueo BRILMA para extirpación de cartílago costal: caso clínico.

The block of the lateral branches of the intercostal nerves in the middle axillary line (BRILMA) is an interfascial ultrasound-guided block for analgesia in thoracic wall and upper abdominal surgery, presenting as an adequate alternative to neuraxial techniques. We present the case of a 49-year-old female scheduled for idiopathic subglottic stenosis repair with a costal cartilage graft from the 10th rib and tracheotomy. At the end of the surgery, unilateral ultrasound-guided BRILMA block with 20ml of ropivacaine 0.2% was performed at the level of the 6th rib, uneventfully. Postoperatively, the patient referred a maximum level of pain of 3/10. There was no opioid consumption after the 2nd postoperative day, although a subcostal incision may produce considerable pain. BRILMA is a superficial block, easily reproducible in most patients. It diminishes the number of punctures needed in the thoracic wall, as well as the risk for pneumothorax and local anesthetic toxicity.

Transversus thoracis muscle plane block in cardiac surgery: a pilot feasibility study.

INTRODUCTION: Cardiac surgery patients often experience significant pain after median sternotomy. The transversus thoracis muscle plane (TTP) block is a newly developed, single-shot nerve block technique that provides analgesia for the anterior chest wall. In this double-blind pilot study, we assessed the feasibility of performing this novel block as an analgesic adjunct. METHODS: All patients aged 18-90 undergoing elective cardiac surgery were randomized to the block or standard care control group on admission to the intensive care unit after surgery. Under ultrasound guidance, patients in the block group received the TTP block with 20 mL of either 0.3% or 0.5% ropivacaine bilaterally, based on weight. The control group did not receive any injections. All blocks were performed by a single anesthesiologist, and data collection was performed by blinded assessors. The primary feasibility outcomes were rate of recruitment, adherence, and adverse events. The rate of recruitment was defined as the ratio of patients giving informed consent to the number of eligible patients who were approached to participate. Secondary outcomes included 12-hour and 24-hour Numeric Rating Scale (NRS) pain scores, 24-hour hydromorphone and acetaminophen requirements, time to extubation, time to first opioid administration, and patient satisfaction (on a yes/no questionnaire) at 24 hours. RESULTS: Twenty patients were approached for this study and 19 were enrolled. Eight patients received the intended intervention in each group. The recruitment rate was 95% of all approached eligible patients, and the adherence rate to treatment group was 94%. There were no block-related adverse events. The mean (SD) NRS pain scores at rest were 3.3 (3.2) in the block group vs 5.6 (3.2) in the control group at 12 hours. At 24 hours, the pain scores were 4.1 (3.9) vs 4.1 (3.3) in the block and control group, respectively. The mean (SD) 24-hour hydromorphone administration was 1.9 (1.1) mg in the block group vs 1.8 (0.9) mg in the control group. DISCUSSION: The TTP block is a novel pain management strategy poststernotomy. The results reveal a high patient recruitment, adherence, and satisfaction rate, and provide some preliminary data supporting safety. TRIAL REGISTRATION NUMBER: NCT03128346.

The influence of affective state on respiratory muscle activity.

Measures of neural respiratory drive through the use of electromyography of the parasternal intercostal muscles (EMGpara) are accurate markers of respiratory load and are reflective of pulmonary function. A previous observation of a significant reduction in EMGpara from a first to second measurement occasion was attributed to participants' acclimatization to the laboratory environment and a reduction in anxiety. This study therefore aimed to investigate whether manipulation of participants' affective state would influence EMGpara and related variables. Healthy adult participants underwent measurement of EMGpara and respiratory flow and volume during exposure to four conditions: no stimulus, music, and tense and calm videos. Respiratory rate (RR), raw neural respiratory drive index (rawNRDI, the product of EMGpara in microvolts and RR) and minute ventilation (VE) differed significantly across conditions: RR and VE were significantly higher in the tense condition than all other conditions (all P<0·05); rawNRDI was higher in the tense compared to the calm video condition (P = 0·03). There was also a significant relationship between EMGpara and subjective tension ratings (measured via visual analogue scale) in the tense condition (Spearman's rho = 0·508, P = 0·016), with multivariate modelling indicating significant interactions between rawNRDI and subjective ratings of both tension and calmness. This suggests that anxiety could contribute to elevated respiratory muscle activity and ventilation. Greater consideration should be given to the influence of anxiety when undertaking measurement of respiratory muscle activity to ensure data accurately represent underlying respiratory load.

Further observations on cardiac modulation of thoracic motoneuron discharges.

Previous analyses of recordings of alpha motoneuron discharges from branches of the intercostal and abdominal nerves in anesthetized cats under neuromuscular blockade demonstrated modulation with the cardiac cycle. This modulation was interpreted as evidence that thoracic somatosensory afferents, most likely muscle spindles, provide a signal to the CNS that could contribute to cardiac interoception. Here, two aspects of these observations have been extended. First, new measurements of thoracic and abdominal EMG activity in spontaneously breathing dogs show that a very similar modulation exists in these rather different circumstances. Second, further analysis of the cat recordings shows that cardiac modulation of the discharges of bulbospinal neurons that transmit the expiratory drive to thoracic motoneurons is weak and of an inappropriate time-course to be a contributor to the effect seen in the motoneurons.

Rhomboid Intercostal and Subserratus Plane Block: A Cadaveric and Clinical Evaluation.

BACKGROUND AND OBJECTIVES: Fascial plane blocks are rapidly emerging to provide safe, feasible alternatives to epidural analgesia for thoracic and abdominal pain. We define a new option for chest wall and upper abdominal analgesia, termed the rhomboid intercostal and subserratus plane (RISS) block. The RISS tissue plane extends deep to the erector spinae muscle medially and deep to the serratus anterior muscle laterally. We describe a 2-part proof-of-concept study to validate the RISS block, including a cadaveric study to evaluate injectate spread and a retrospective case series to assess dermatomal coverage and analgesic efficacy. METHODS: For the cadaveric portion of the study, bilateral ultrasound-guided RISS blocks were performed on 6 fresh cadavers with 30 mL of 0.5% methylcellulose with india ink. For the retrospective case series, we present 15 patients who underwent RISS block or RISS catheter insertion for heterogeneous indications including abdominal surgery, rib fractures, chest tube-associated pain, or postoperative incisional chest wall pain. RESULTS: In the cadaveric specimens, we identified staining of the lateral branches of the intercostal nerves from T3 to T9 reaching the posterior primary rami deep to the erector spinae muscle medially. In the clinical case series, dermatomal coverage was observed in the anterior hemithorax with visual analog pain scores less than 5 in patients who underwent both single-shot and continuous catheter infusions. CONCLUSIONS: Our preliminary cadaveric and clinical data suggest that RISS block anesthetizes the lateral cutaneous branches of the thoracic intercostal nerves and can be used in multiple clinical settings for chest wall and upper abdominal analgesia.

Task-dependent output of human parasternal intercostal motor units across spinal levels.

KEY POINTS: During breathing, there is differential activity in the human parasternal intercostal muscles and the activity is tightly coupled to the known mechanical advantages for inspiration of the same regions of muscles. It is not known whether differential activity is preserved for the non-respiratory task of ipsilateral trunk rotation. In the present study, we compared single motor units during resting breathing and axial rotation of the trunk during apnoea. We not only confirmed non-uniform recruitment of motor units across parasternal intercostal muscles in breathing, but also demonstrated that the same motor units show an altered pattern of recruitment in the non-respiratory task of trunk rotation. The output of parasternal intercostal motoneurones is modulated differently across spinal levels depending on the task and these results help us understand the mechanisms that may govern task-dependent differences in motoneurone output. ABSTRACT: During inspiration, there is differential activity in the human parasternal intercostal muscles across interspaces. We investigated whether the earlier recruitment of motor units in the rostral interspaces compared to more caudal spaces during inspiration is preserved for the non-respiratory task of ipsilateral trunk rotation. Single motor unit activity (SMU) was recorded from the first, second and fourth parasternal interspaces on the right side in five participants in two tasks: resting breathing and 'isometric' axial rotation of the trunk during apnoea. Recruitment of the same SMUs was compared between tasks (n = 123). During resting breathing, differential activity was indicated by earlier recruitment of SMUs in the first and second interspaces compared to the fourth space in inspiration (P < 0.01). By contrast, during trunk rotation, the same motor units showed an altered pattern of recruitment because SMUs in the first interspace were recruited later and at a higher rotation torque than those in the second and fourth interspaces (P < 0.05). Tested for a subset of SMUs, the reliability of the breathing and rotation tasks, as well as the SMU recruitment measures, was good-excellent [intraclass correlation (2,1): 0.69-0.91]. Thus, the output of parasternal intercostal motoneurones is modulated differently across spinal levels depending on the task. Given that the differential inspiratory output of parasternal intercostal muscles is linked to their relative mechanical effectiveness for inspiration and also that this output is altered in trunk rotation, we speculate that a mechanism matching neural drive to muscle mechanics underlies the task-dependent differences in output of axial motoneurone pools.