Daily Anesthesiology Research Analysis

BACKGROUND: Atelectasis is common during general anaesthesia and contributes to postoperative pulmonary complications. Despite preventive strategies targeting established underlying mechanisms, extensive atelectasis still often occurs, suggesting that additional factors may be involved. We tested the hypothesis that hypotension contributes to atelectasis formation during anaesthesia. METHODS: We conducted a randomised, evaluator-blinded crossover study in 12 anaesthetised, mechanically ventilated pigs under conditions simulating anaesthesia induction, in which preoxygenation was followed by either normotension or profound hypotension induced with nitroprusside. The primary outcome was total atelectasis volume, measured by computed tomography. Pulmonary blood flow distribution was assessed using [ RESULTS: Atelectasis volume was greater during induced hypotension (median MAP 46 mmHg [interquartile range: 43-49]), compared with normotension (median MAP 85 mmHg [81-93]) in 11 of 12 pigs (median difference 20 ml [95% CI 9-38]; P<0.001). During hypotension, pulmonary blood flow was redistributed towards the dorsal lung regions, with hypotension resulting in a ratio of dorsal to total pulmonary blood flow of 182% (170-186), compared with 129% (104-150) with normotension. Mixed venous oxygen saturation was lower during hypotension (43% [27-53]) compared with normotension (48% [44-56]). CONCLUSIONS: In this experimental model of anaesthesia induction, profound hypotension increased atelectasis compared with normotension. The findings are consistent with redistribution of pulmonary blood flow with low oxygen saturation towards dorsal lung regions that are prone to develop absorption atelectasis. Hypotension during induction of general anaesthesia might therefore be a hitherto unrecognised contributor to pulmonary atelectasis. TRIAL REGISTRATION: www.animalstudyregistry.org (https://doi.org/10.17590/asr.0000369).

OBJECTIVE: To evaluate the analgesic efficacy of thoracic paravertebral block (TPVB) with different doses of liposomal bupivacaine (LB) or ropivacaine in patients undergoing single-port thoracoscopic lung surgery. METHODS: A total of 105 patients scheduled for video-assisted single-port thoracoscopic lung surgery were randomized in a 1:1:1 ratio into three groups: low-dose LB group (group LL), high-dose LB group (group HL), or ropivacaine group (group R). All received ultrasound-guided TPVB at the T5/6 level preoperatively. The primary outcome was the area under the curve (AUC) of NRS of pain at activity (AUC-aNRS) from 1 to 72 h postoperatively. Secondary outcomes included the AUC of NRS of pain at rest (AUC-rNRS) from 1 to 72 h postoperatively, NRS of pain at rest and at activity at 1, 6, 24, 48, and 72 h postoperatively, and the cumulative opioid consumption at 24, 48, and 72 h postoperatively. Additionally, postoperative recovery and adverse events were assessed. RESULTS: AUC-aNRS differed significantly among groups ( CONCLUSION: LB combined with TPVB is not superior to ropivacaine for postoperative analgesia in single-port thoracoscopic lung resection. This study is the first to compare the analgesic efficacy of TPVB combined with two doses of LB and traditional ropivacaine in patients undergoing thoracoscopic lung surgery.Within 72 hours postoperatively, neither low-dose nor high-dose LB showed superiority over ropivacaine in reducing NRS of pain or opioid use. High-dose LB showed dose-dependent analgesic and opioid-sparing effects, though the pain reduction was clinically limited.Single-point TPVB with LB alone may not be an effective alternative to ropivacaine, optimizing strategies (e.g. ultrasound-guided multi-point injection, combining with plain bupivacaine) are needed to improve LB’s efficacy in TPVB in the future.

BACKGROUND: Effective pain management for rib fractures is crucial to prevent pulmonary complications and facilitate recovery. UGPB has emerged as a promising regional analgesic technique for these patients. OBJECTIVE: This systematic review with meta-analysis aims to evaluate the effectiveness of UGPB compared with standard care for managing pain associated with rib fractures. In this review, the term UGPB serves as an umbrella term for various UGPBs, with the erector spinae plane block (ESPB) and serratus anterior plane block (SAPB) being the two specific techniques evaluated in the included studies. METHODS: This study conducted a comprehensive search of electronic databases including PubMed, Embase, Cochrane Library, Web of science and China National Knowledge Infrastructure (CNKI) up to 31 March 2026. Eligibility criteria were established based on the inclusion of adult patients diagnosed with rib fractures treated with UGPB versus standard care. The primary outcome was pain intensity, assessed using a Visual Analog Scale (VAS) or Numeric Rating Scale (NRS). Secondary outcomes included total amount of analgesic consumption, respiratory function (PaO₂ and PaCO₂ via arterial blood gas analysis), and adverse events. Risk of bias was assessed using the Cochrane Risk of Bias (RoB 2) tool. The certainty of evidence for primary outcomes was assessed using the GRADE framework. Continuous outcomes were pooled as standardized mean differences (SMD) with 95% confidence intervals using a random-effects model; heterogeneity was assessed via I². RESULTS: Nine randomized controlled trials (RCTs) involving 664 participants were included. Most studies raised some concerns regarding risk of bias, primarily related to the randomization process, allocation concealment, or blinding of participants and personnel; four studies were judged to be at high overall risk of bias, and none at low risk. The pooled data from 7 studies (423 participants) showed that UGPB significantly reduced pain scores (SMD = -0.44, 95% CI: -0.72 to -0.16; I² = 51%; p < 0.01). A leave-one-out sensitivity analysis for pain scores (excluding one study at a time from the 7 included studies) yielded SMDs ranging from - 0.49 to -0.38 (all p < 0.05) and I² ranging from 45% to 58%, confirming the robustness of this finding. For respiratory parameters, based on 3 studies (198 participants) there were no significant differences in PaCO₂ levels (SMD = -0.02, 95% CI: -0.56 to 0.61; I² = 75%; p = 0.95). PaO₂ levels remained stable (SMD = 0.04, 95% CI: -0.24 to 0.32; I² = 0%; p = 0.78). The effect on analgesic consumption, from 7 studies (546 participants), was not significant (SMD = -0.09, 95% CI: -1.61 to 1.43; I² = 96%; p = 0.91). The certainty of evidence was low for pain scores and very low for analgesic consumption and blood gas parameters according to GRADE. CONCLUSION: UGPB reduces pain scores in patients with rib fractures, with a small-to-moderate effect size (SMD = -0.44, 95% CI: -0.72 to -0.16), and does not appear to compromise respiratory function based on stable PaCO₂ and PaO₂ levels. However, given the concerns regarding risk of bias and heterogeneity, these findings should be interpreted cautiously. High heterogeneity in analgesic consumption and other outcomes underscores the need for further high-quality research to standardize protocols and optimize the use of UGPB in clinical practice. PROSPERO REGISTRATION: CRD420251077539 (registered 20 June 2025).