Erector Spinae Plane Block versus Continuous Perineural Local Anesthetic Infusion for Postoperative Pain Control After Supraclavicular Decompression for Neurogenic Thoracic Outlet Syndrome: A Matched Case-Control Comparison.

OBJECTIVE: The purpose of this study was to determine if single injection erector spinae plane blocks are associated with improved pain control, opioid use, numbness, length of stay, or patient satisfaction compared to intraoperatively placed continuous perineural infusion of local anesthetic after decompression of neurogenic thoracic outlet syndrome. METHODS: This is a retrospective cohort study at a tertiary academic center of eighty patients that underwent supraclavicular decompression for thoracic outlet syndrome between May 2019 and January 2020. Forty consecutive patients treated with single-injection preoperative erector spinae plane blocks were retrospectively compared to 40 age- and gender-matched controls treated with continuous perineural infusion. RESULTS: The primary outcome of mean pain scores was not significantly different between the erector spinae and perineural infusion groups over the three-day study period (4.2-5.3 vs 3.0-5.1 P=0.08). On post-operative day 0, mean pain scores were significantly higher in the erector spinae group (4.2 vs 3.0, P=0.02). While statistically significant, the score was still lower in the erector spinae group on day 0 than on day 1,2, or 3 in either group. Opioid use, nausea, length of stay and patient satisfaction were also similar. Upper extremity numbness was significantly less severe in the erector spinae group (36% vs 73% moderate-extreme, P=0.03) at 6-month follow-up. CONCLUSIONS: Seventy-two-hour perineural local anesthetic infusion did not provide superior analgesia compared to preoperative single-injection erector spinae blocks. Furthermore, there was significantly less long-term postoperative numbness associated with erector spinae blocks compared to perineural local anesthetic infusion.

Practical Training of Anesthesia Clinicians in Electroencephalogram-Based Determination of Hypnotic Depth of General Anesthesia.

BACKGROUND: Electroencephalographic (EEG) brain monitoring during general anesthesia provides information on hypnotic depth. We hypothesized that anesthesia clinicians could be trained rapidly to recognize typical EEG waveforms occurring with volatile-based general anesthesia. METHODS: This was a substudy of a trial testing the hypothesis that EEG-guided anesthesia prevents postoperative delirium. The intervention was a 35-minute training session, summarizing typical EEG changes with volatile-based anesthesia. Participants completed a preeducational test, underwent training, and completed a posteducational test. For each question, participants indicated whether the EEG was consistent with (1) wakefulness, (2) non-slow-wave anesthesia, (3) slow-wave anesthesia, or (4) burst suppression. They also indicated whether the processed EEG (pEEG) index was discordant with the EEG waveforms. Four clinicians, experienced in intraoperative EEG interpretation, independently evaluated the EEG waveforms, resolved disagreements, and provided reference answers. Ten questions were assessed in the preeducational test and 9 in the posteducational test. RESULTS: There were 71 participants; 13 had previous anesthetic-associated EEG interpretation training. After training, the 58 participants without prior training improved at identifying dominant EEG waveforms (median 60% with interquartile range [IQR], 50%-70% vs 78% with IQR, 67%-89%; difference: 18%; 95% confidence interval [CI], 8-27; P < .001). In contrast, there was no significant improvement following the training for the 13 participants who reported previous training (median 70% with IQR, 60%-80% vs 67% with IQR, 67%-78%; difference: -3%; 95% CI, -18 to 11; P = .88). The difference in the change between the pre- and posteducational session for the previously untrained versus previously trained was statistically significant (difference in medians: 21%; 95% CI, 2-28; P = .005). Clinicians without prior training also improved in identifying discordance between the pEEG index and the EEG waveform (median 60% with IQR, 40%-60% vs median 100% with IQR, 75%-100%; difference: 40%; 95% CI, 30-50; P < .001). Clinicians with prior training showed no significant improvement (median 60% with IQR, 60%-80% vs 75% with IQR, 75%-100%; difference: 15%; 95% CI, -16 to 46; P = .16). Regarding the identification of discordance, the difference in the change between the pre- and posteducational session for the previously untrained versus previously trained was statistically significant (difference in medians: 25%; 95% CI, 5-45; P = .012). CONCLUSIONS: A brief training session was associated with improvements in clinicians without prior EEG training in (1) identifying EEG waveforms corresponding to different hypnotic depths and (2) recognizing when the hypnotic depth suggested by the EEG was discordant with the pEEG index.