Daily Anesthesiology Research Analysis

BACKGROUND: Thoracic paravertebral block (TPVB) can provide effective analgesia for patients undergoing video-assisted thoracoscopic surgery (VATS). However, the duration of analgesia achieved with conventional local anesthetics combined with dexamethasone remains limited. This study aimed to determine if liposomal bupivacaine (LB) is superior to bupivacaine combined with dexamethasone (BD) with respect to duration of postoperative analgesia in VATS patients. METHODS: Adults scheduled for VATS were randomized to treatment with LB or BD. The primary outcome was duration of analgesia. Secondary outcomes involved Numeric Rating Scale (NRS) pain scores, cumulative oxycodone consumption, total intraoperative sufentanil consumption, first times to ambulation and flatus, length of hospital stay, patient satisfaction level, and incidence of adverse reactions. RESULTS: Of 93 total subjects, 78 were randomized into two groups (n=39 each). The LB group demonstrated a significantly prolonged duration of analgesia compared with the BD group (1160.4±403.8 min vs 743.1±216.8 min, p<0.001), with a mean increase of 417 min (a 56% extension). LB was associated with lower resting and cough NRS pain scores on the first postoperative day. The 72-hour area under the curve values for scores for resting pain (67.5 vs 87.9) and pain during cough (213.9 vs 244.0) were lower for the LB group versus the BD group. In exploratory analyses, cumulative oxycodone consumption on the first postoperative day was numerically lower in the LB group. Subjects receiving treatment LB had lower cumulative oxycodone consumption on the first postoperative day, earlier times to first ambulation and first flatus, and higher satisfaction scores as compared with subjects receiving BD. There was no significant difference between the two groups in terms of total intraoperative sufentanil consumption, duration of hospital stay, or incidence of adverse events. CONCLUSION: In VATS patients receiving TPVB, LB significantly prolonged the duration of postoperative analgesia compared with BD. Exploratory secondary outcomes suggested modest improvements in early pain profiles and potential opioid-sparing and early recovery benefits. TRIAL REGISTRATION NUMBER: ChiCTR2500095090.

BACKGROUND: Recirculation is a major contributor to refractory hypoxemia during veno-venous ECMO (V-V ECMO), yet it remains difficult to measure at the bedside. In an animal study, we applied the trans-ECMO thermodilution (TET) to quantify the phenomenon, identify its determinants and estimate the mixed venous oxygenation non-invasively. METHODS: Eight pigs (65±3 kg) were anesthetized and cannulated for femoral-jugular V-V ECMO. Acute respiratory distress syndrome (ARDS) was induced using oleic (n=4) or hydrochloric acid (n=4) targeting a PaO 2 /FiO 2 of 150 mmHg. The experiment lasted 24 hours, with serial measurements of blood gases, hemodynamics and respiratory mechanics. TET was performed by injecting a bolus of cold saline downstream the membrane lung and by recording the resulting temperature changes in the drainage and return cannulas. Recirculation was calculated as the ratio of the areas under the temperature-time curves (AUCs). The determinants of the recirculation were analyzed with mixed linear models, including a random intercept. The measured recirculation was incorporated in a series of mass-transfer equations to estimate the mixed venous oxygen content and saturation. RESULTS: Median recirculation was 7.4% IQR [1.1-22.0] and presented large inter-subject variability. In 55% of measurements, recirculation was <10% (minimal recirculation, MR). In the remaining measurements, the recirculation measured 27.4 [15.0- 43.5] (significant recirculation, SR). The ratio of extracorporeal blood flow to cardiac output (ECS F ) measured 0.63 [0.55-0.72] and was the only physiological factor correlated with recirculation (overall Pearson correlation coefficient r=0.67, in the SR r =0.81). The distance between the tip of the cannulas was, in our setup, non-significantly associated to the recirculation (p=0.74). An increased recirculation was modestly associated with a decreased mixed venous PO 2 (r=-0.37). The non-invasive estimation of the mixed venous oxygenation was highly accurate (r=0.98, bias +0.48 ml/100 ml for the oxygen content, r=0.98, bias +4% for saturation). CONCLUSIONS: TET is a promising technique to measure the recirculation during V-V ECMO. Increasing the blood flow does not always lead to an improvement in oxygenation given the tight relationship between ECS F and recirculation. The proposed numerical method allows the non-invasive estimation of the mixed venous oxygenation without the need of a pulmonary artery catheter.

OBJECTIVE: A definition of refractory septic shock is necessary to guide diagnosis, management, prognostication, research, and future guidelines for this most severe form of the disease. We sought to achieve consensus on clinical criteria that would be used to define refractory septic shock. DESIGN: Review of literature, expert panel position statements, and Delphi rounds with an international expert group. SETTING: Consensus was defined as having at least 75% of panellists in agreement or disagreement on the three highest or lowest levels of a 7-point Likert scale or based on responses to single- or multiple-choice questions, respectively. SUBJECTS: A panel of multinational, multiprofessional, and multidisciplinary critical care experts assembled by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine (57 invitations and 56 participants). MEASUREMENTS AND MAIN RESULTS: A five-round Delphi process was conducted for consensus and stability. The steering committee proposed 34 statements, and five of them were rejected by panel experts after round 2. Among 29 statements selected from eight domains, consensus was reached for 13. The panel agreed on the need for a comprehensive consensus set of clinical criteria for refractory septic shock. Markers of organ dysfunction (75%, 2 rounds), tissue perfusion (91.1%, 2 rounds) including lactate (94.6%, 2 rounds) and capillary refill time (76.8%, 2 rounds), assessment of fluid responsiveness after initial resuscitation (92.9%, 5 rounds), and use of vasoactive drugs at norepinephrine equivalents greater than 0.5 µg/kg/min (75.0%, 3 rounds) were selected as clinical criteria of refractory septic shock. The use of critical care ultrasound (CCUS) (92.9%, 3 rounds) was the single diagnostic modality that reached a consensus-based agreement. CONCLUSIONS: A consensus for 13 criteria to frame the definition of refractory septic shock was reached. Refractory septic shock is characterised by persistently elevated lactate concentrations and or prolonged capillary refill time in patients with septic shock who are fluid unresponsive, require a norepinephrine base equivalent dose greater than 0.5 µg per kilogram per minute, and undergo CCUS assessment when mixed shock is suspected.