Hemodynamic timing in resting-state and breathing-task BOLD fMRI.

The blood flow response to a vasoactive stimulus demonstrates regional heterogeneity across both the healthy brain and in cerebrovascular pathology. The timing of a regional hemodynamic response is emerging as an important biomarker of cerebrovascular dysfunction, as well as a confound within fMRI analyses. Previous research demonstrated that hemodynamic timing is more robustly characterized when a larger systemic vascular response is evoked by a breathing challenge, compared to when only spontaneous fluctuations in vascular physiology are present (i.e., in resting-state data). However, it is not clear whether hemodynamic delays in these two conditions are physiologically interchangeable, and how methodological signal-to-noise factors may limit their agreement. To address this, we generated whole-brain maps of hemodynamic delays in nine healthy adults. We assessed the agreement of voxel-wise gray matter (GM) hemodynamic delays between two conditions: resting-state and breath-holding. We found that delay values demonstrated poor agreement when considering all GM voxels, but increasingly greater agreement when limiting analyses to voxels showing strong correlation with the GM mean time-series. Voxels showing the strongest agreement with the GM mean time-series were primarily located near large venous vessels, however these voxels explain some, but not all, of the observed agreement in timing. Increasing the degree of spatial smoothing of the fMRI data enhanced the correlation between individual voxel time-series and the GM mean time-series. These results suggest that signal-to-noise factors may be limiting the accuracy of voxel-wise timing estimates and hence their agreement between the two data segments. In conclusion, caution must be taken when using voxel-wise delay estimates from resting-state and breathing-task data interchangeably, and additional work is needed to evaluate their relative sensitivity and specificity to aspects of vascular physiology and pathology.

Comparison of erector spinae plane and paravertebral nerve blocks for postoperative analgesia in children after the Nuss procedure: study protocol for a randomized controlled non-inferiority clinical trial.

BACKGROUND: Thoracic paravertebral block (TPVB) is a widely advocated regional technique for alleviating postoperative pain in children undergoing elective pectus excavatum repair. However, this technique is associated with some undesirable adverse events. Recently, the erector spinae plane block (ESPB) has been introduced as a practical alternative to the TPVB in thoracic surgery. This interfascial regional anesthesia technique interrupts pain sensation by injecting local anesthetics between the muscular layers of the thoracic wall. Several case series described it as an effective pain management technique following pectus excavatum repair. Therefore, this trial is designed to test the hypothesis that ESPB is non-inferior to TPVB in postoperative pain control after pectus excavatum repair. METHODS: This is a prospective randomized double-blind non-inferiority trial. A total of 40 patients aged 4 to 18 years undergoing Nuss surgery will be randomly assigned to receive pain treatment with either ESPB or TPVB. All patients will receive additional systemic multimodal analgesia with an intravenous patient-controlled analgesia pump and acetaminophen. The primary outcome is the pain intensity at rest, 24 h postoperatively. Secondary outcomes include accumulated morphine-equivalent consumption, postoperative pain scores, emergence agitation incidence, time of the first mobilization, time to first rescue analgesia, complications related to pain treatment, and morphine-related adverse events. DISCUSSION: This will the first randomized controlled trial to compare ESPB with TPVB for analgesia after pectus excavatum repair. This trial aims to provide important clinical evidence to elaborate on the analgesic mechanism of ESPB in children. TRIAL REGISTRATION: ClinicalTrials.gov NCT05034601 . This trial was prospectively registered.

The impact of ultrasound-guided transmuscular quadratus lumborum block combined with local infiltration analgesia for arthroplasty on postoperative pain relief.

STUDY OBJECTIVE: This study aimed to evaluate the efficacy of ultrasound-guided transmuscular quadratus lumborum block (QLB) combined with local infiltration analgesia (LIA) for pain management and recovery in patients who have undergone total hip arthroplasty (THA) via a posterolateral approach. DESIGN: This was a prospective, randomized controlled trial. SETTING: We collected data in the preoperative area, operating room, and bed ward. PATIENTS: A total of 80 patients with American Society of Anesthesiology functional status scores of II-III were included and assigned to two groups, and all 80 patients were included in the final analysis. INTERVENTIONS: All included patients were randomly assigned to the nerve block (group N) or the control group (group C). Patients in the group N received transmuscular QLB combined with LIA, while patients in the group C received only LIA. MEASUREMENTS: The primary outcome was postoperative pain during the first active motion: it was measured at six hours after surgery and assessed using a visual analog scale (VAS). Secondary outcomes were the resting VAS scores in the post-anesthesia care unit (PACU) and at 2, 6, 12, 24, 48, and 72 h after surgery; VAS scores during motion at 12, 24, 48, and 72 h after surgery; intraoperative consumption of opioids; postoperative consumption of morphine hydrochloride; frequency of sleep interruption due to pain on the night of surgery; time until the first "walk out of the bed" after surgery; muscle strength of the quadriceps femoris; and postoperative adverse effects. MAIN RESULTS: Compared to the group C, patients in the group N had significantly lower VAS scores during motion at 6, 12, and 24 h after surgery, as well as lower resting VAS scores in the PACU and at 2, 6, 12, and 24 h after surgery. Patients in the group N also consumed significantly smaller amounts of intraoperative opioids and morphine after surgery. Patients in the group N reported significantly fewer interruptions in sleep due to pain on the night of surgery and were able to "walk out of the bed" significantly earlier than those in the group C. There was no significant difference between the two groups in muscle strength of the quadriceps femoris or incidence of postoperative adverse effects. CONCLUSIONS: Compared to treatment with LIA alone, ultrasound-guided transmuscular QLB combined with LIA can provide better postoperative pain relief and enhance the recovery of THA patients, since it does not cause quadriceps femoris muscle weakness and is associated with significantly lower need for intraoperative opioids.