Daily Anesthesiology Research Analysis

BACKGROUND: The optimal preoperative management of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) remains debated. This meta-analysis of randomized controlled trials (RCTs) assessed withholding vs. continuing ACEIs/ARBs on intraoperative hypotension and postoperative outcomes. METHODS: PubMed, Web of Science, and China Biology Medicine were comprehensively searched to identify RCTs comparing preoperative withholding ACEIs/ARBs with a continuing therapy in adult patients. Two authors independently extracted and pooled data using a random-effects model. The primary outcome was the incidence of intraoperative hypotension. Secondary outcomes included duration of intraoperative hypotension, vasopressor use, postoperative hypotension and hypertension, major adverse cardiovascular events, acute kidney injury, duration of mechanical ventilation, length of stay in ICU and hospital, and 30-d mortality. Evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation approach. RESULTS: Fourteen RCTs with 4063 patients were included. Withholding ACEIs/ARBs before noncardiac surgery was associated with a reduced incidence of intraoperative hypotension (36.4% vs. 48.4%; risk ratio = 0.73, 95% confidence interval = 0.60-0.88, CONCLUSIONS: While withholding ACEIs/ARBs may reduce intraoperative hypotension, the very low certainty of evidence underscores the need for future research to confirm clinical implications. SYSTEMATIC REVIEW REGISTRATION: PROSPERO (CRD42021253965).

BACKGROUND: A limitation to widespread use of pediatric lumbar plexus blocks is a scarcity of pharmacokinetic data. Concerns about absorption and consequent toxicity promote low doses, resulting in frequent episodes of breakthrough pain. The authors determined population pharmacokinetics of unbound ropivacaine and its toxic metabolite 2',6'-pipecoloxylidide (PPX) after a bolus dose and during continuous infusion to simulate current dosing guidelines relative to the toxic threshold of the combined effects of ropivacaine and PPX in the pediatric population. METHODS: A total of 20 healthy children, age 4 to 18 yr, undergoing unilateral hip/femur surgery who received lumbar plexus blocks with 0.2% ropivacaine bolus (2 mg/kg) and an infusion (0.4 mg · kg -1 · h -1 ) were prospectively enrolled. Blood samples were collected at regular intervals over 26 h to measure total and unbound plasma ropivacaine and PPX concentrations. RESULTS: The concentration versus time plots show an approximately 5-fold range of plateau unbound plasma ropivacaine concentrations and 10-fold range of PPX among the patients, suggesting similar variability in unbound ropivacaine and PPX clearances, respectively. Ropivacaine and PPX exposure simulations using standard infusion rates (0.4 mg · kg -1 · h -1 ) with regular bolus dose administration of 0.2 mg/kg resulted in the 95th percentile of sum of unbound ropivacaine plus 1/12 PPX concentrations approaching the estimated toxic threshold due to late-occurring approach to high steady state plasma concentrations of PPX. Discontinuing the continuous infusion and replacing it with larger bolus doses every 6 h resulted in lower simulated plasma ropivacaine and PPX plasma concentrations. CONCLUSIONS: Pharmacokinetic modeling supports a bolus dose of 2 mg/kg, continuous infusion rates of ropivacaine at 0.4 mg · kg -1 · h -1 , and boluses every 6 h of 0.2 mg/kg in healthy children for lumbar plexus blockade for the first 24 h. After that, with currently accepted toxic thresholds for ropivacaine and PPX, consideration should be given to dosing strategies that reduce or eliminate infusions and support timed boluses.

BACKGROUND: As an adjuvant, dexamethasone can enhance the analgesic intensity and prolong the duration of nerve blocks. However, to date, no studies have compared the effectiveness of different administration routes of dexamethasone for thoracoscopy-guided thoracic paravertebral block (TTPB). This prospective randomized controlled study evaluated the postoperative analgesic effects of dexamethasone administered intravenously or perineurally in combination with ropivacaine for TTPB in patients undergoing radical lung cancer resection. METHODS: A total of 150 patients were randomly assigned to receive dexamethasone intravenously (Group I, n=75) or perineurally (Group D, n=75). Before wound closure, patients in Group I underwent TTPB with ropivacaine while receiving an intravenous dexamethasone injection, whereas patients in Group D received a perineural mixture of ropivacaine and dexamethasone. The primary outcome was the time to first postoperative rescue analgesia. Secondary outcomes included Visual Analogue Scale (VAS) scores, postoperative 48-hour sufentanil consumption in patient-controlled intravenous analgesia (PCIA), postoperative blood glucose levels, postoperative recovery parameters, and incidence of adverse events. RESULTS: Compared with Group I, Group D showed a significantly longer time to first postoperative rescue analgesia, lower VAS scores at all assessed time points, and reduced postoperative 48-hour sufentanil consumption. Group D also showed a smaller increase in postoperative blood glucose levels, an earlier time to first ambulation and a shorter postoperative hospital stay (all CONCLUSION: In TTPB, perineural dexamethasone administration with ropivacaine provided superior and longer-lasting analgesia compared with intravenous administration. Additionally, it accelerated postoperative recovery and shortened hospital stay.