Korean Journal of Anesthesiology最新文献

Heterogeneity is a critical but unavoidable aspect of meta-analyses that reflects differences in study outcomes beyond what is expected by chance. These variations arise from differences in the study populations, interventions, methodologies, and measurement tools and can influence key meta-analytical outputs, including pooled effect sizes, confidence intervals, and overall conclusions. Systematic reviews and meta-analyses combine evidence from diverse studies; thus, a clear understanding of heterogeneity is necessary for reliable and meaningful interpretations of the results. This review examines the concepts, sources, measurement techniques, and implications of this heterogeneity. Statistical tools (e.g., Cochran's Q, I2, and τ2) quantify heterogeneity, whereas τ and prediction intervals, as they use the same units, aid in the intuitive understanding of heterogeneity. The choice between fixed- and random-effects models can also significantly affect the handling and interpretation of heterogeneity in meta-analyses. Effective management strategies include subgroup analyses, sensitivity analyses, and meta-regressions, which identify sources of variability and strengthen the robustness of the findings. Although heterogeneity complicates the synthesis of a single effect size, it offers valuable insights into patterns and differences among studies. Recognizing and understanding heterogeneity is vital for accurately synthesizing the evidence, which can indicate whether an intervention has consistent effects, benefits, or harms. Rather than viewing heterogeneity as inherently good or bad, researchers and clinicians should consider it a key component of systematic reviews and meta-analyses, allowing for a deeper understanding and more nuanced application of pooled findings. Addressing heterogeneity ultimately enhances the reliability, applicability, and overall impact of the conclusions of meta-analyses.

Background: The ideal intravenous maintenance and resuscitation fluid for patients undergoing orthotopic liver transplantation (OLT) remains unknown. We aimed to determine whether bicarbonate-buffered solution was non-inferior to Plasma-LyteTM in preventing metabolic acidosis during OLT.

Methods: We conducted a pilot single-center, open-label, randomized trial to compare the physiological effects of intravascular volume maintenance with a bicarbonate-buffered solution vs. Plasma-LyteTM in adults undergoing OLT. Non-inferiority was defined as a median difference in the standard base excess (SBE) of less than -2.5 mEq/L. The primary endpoint was the SBE at 5 minutes post-reperfusion. Quantile regression analysis was applied to confirm non-inferiority. Secondary endpoints included other forms of acid-base and electrolyte imbalances at pre-specified time points and postoperative complications.

Results: We randomized 52 adults undergoing OLT. The median (Q1, Q3) volume infused was 5 000 (3 125, 7 000) ml in the bicarbonate-buffered solution group and 5 500 (4 000, 10 500) ml in the Plasma-LyteTM group (P = 0.37). The median (Q1, Q3) SBE at 5 minutes post-reperfusion was -4.857 (-6.231, -3.565) mEq/L in patients receiving bicarbonate-buffered solution and -4.749 (-7.574, -2.963) mEq/L amongst those in the Plasma-LyteTM group. The estimated median difference by quantile regression was -0.043 mEq/L (95% CI [-1.988 to 1.902] mEq/L; one-sided P = 0.015). There were no significant differences in the acid-base secondary outcomes, number of complications, or patient mortality. There were no reported adverse events or safety concerns associated with the use of either solution.

Conclusions: A bicarbonate-buffered solution was non-inferior to Plasma-LyteTM for maintaining acid-base homeostasis post-reperfusion in OLT patients.

Background: The rainbow pleth variability index (RPVI) is a newly introduced multiwavelength variant of the pleth variability index (PVI). However, the clinical data on RPVI remains limited. This study retrospectively compared PVI and RPVI in non-cardiothoracic surgery patients using pulse pressure variation (PPV) as a reference.

Methods: Adult patients (≥20 years) who underwent non-cardiothoracic surgery under general anesthesia and had concurrent RPVI, PVI, and invasive arterial pressure monitoring were included. Repeated-measures correlation was used to evaluate the association with PPV. Agreement was assessed using nested Bland-Altman analysis, and receiver operating characteristic (ROC) curve analysis was conducted to assess the predictive performance for detecting high PPV (>13%).

Results: A total of 86 cases (195.3 h of data) were analyzed. The RPVI showed a stronger correlation with PPV than with PVI (r = 0.511 vs. r = 0.243). The Bland-Altman analysis revealed narrower limits of agreement for the RPVI, indicating greater precision. RPVI also demonstrated better predictive performance, with an area under the curve of 0.813 (95% CI, 0.804-0.821) compared to 0.663 (95% CI, 0.653-0.674) for PVI (P < 0.001). The optimal thresholds for detecting PPV >13% were 8.5 for RPVI and 13.5 for PVI.

Conclusions: RPVI demonstrated superior performance compared with PVI, showing a stronger correlation and greater precision with respect to PPV, as well as an improved ability to detect states of elevated PPV. While not a direct substitute for PPV, RPVI may serve as a promising non-invasive index for fluid status assessment.

Simulation-based training provides a psychologically and physically safe environment for health-care professionals to practice exercises repetitively without placing patients at risk. Furthermore, it allows them to rehearse rare or high-risk clinical scenarios that are rarely encountered in daily practice. In addition to technical procedures, anesthesiologists need to master non-technical skills (NTS), such as communication, teamwork, leadership, and decision-making. These cognitive and social abilities complement technical expertise, and their absence is a leading cause of errors in emergency situations. In situ simulation (ISS) training, which involves conducting realistic simulation training in actual clinical settings, is one of the most time-efficient and effective formats for training of both technical skills and NTS. ISS minimizes travel time and can be integrated into clinical workflows. In this review, we explore ISS training in terms of its definition and implementation, evidence of its effectiveness, its role in NTS training, and related emerging trends (e.g., virtual/augmented reality).

Background: Understanding the effects of age and body weight on volume kinetics may provide practical guidance for fluid administration in clinical practice. This study aimed to quantify the effects of age and body weight on the volume kinetic parameters in healthy volunteers with varying ages and body weights.

Methods: Eighteen healthy volunteers were enrolled in this study. These volunteers received 40 ml/kg of Ringer's lactate solution for 60 min; for safety reasons, volunteers aged > 65 years received 30 ml/kg. The maximum amount of administered fluid was limited to 3600 ml. Venous blood samples were collected at preset intervals to determine the hemoglobin concentrations and hematocrit percentage. NONMEM 7.5 (ICON PLC) was used to perform the population-based volume kinetic analysis.

Results: A total of 122 plasma dilution data points were used from 18 volunteers to determine the pharmacokinetic characteristics of Ringer's lactate solution. Distribution and elimination could be well explained using a two-volume model. The central volume of distribution at baseline (Vc0) and the distributional clearance (kt) between the central and peripheral compartments decreased as age increased. A difference in elimination clearance (kr) was observed based on age, with a value of 60 years (≥ 60 y: 50.2 ml/min; < 60 y: 156 ml/min). Body weight was not a significant covariate for the volume kinetic parameters.

Conclusions: These findings can serve as reference data for determining the appropriate amount of Ringer's lactate solution to administer to patients of different ages in clinical practice.

Background: The risk of difficult mask ventilation (DMV) is high in patients with obesity. Therefore, we evaluated the accuracy of ultrasound-measured skin-to-hyoid bone distance (SHD) for predicting DMV in such population.

Methods: This prospective observational study included adult patients with obesity scheduled for elective surgery. Preoperative airway assessment included the modified Mallampati test, thyromental distance, sternomental distance, upper lip bite test, mouth opening, neck mobility, STOP-Bang score, and the SHD measured by a handheld ultrasound probe. The mask ventilation grade was evaluated using the 4-level Han score, and grades 3 and 4 were considered as DMV. The primary outcome was the ability of SHD to predict DMV using area under the receiver operating characteristic curve (AUC) analysis. A multivariate model including the STOP-Bang score, modified Mallampati test, upper lip bite test, and SHD was also assessed.

Results: Data from 326 patients were analyzed. The DMV incidence was 22/326 (6.7%). Patients with DMV were predominantly male and had higher weight, STOP-Bang score, modified Mallampati grade, upper lip bite class, and SHD than did those with easy mask ventilation. The AUC (95% confidence interval) of the SHD for predicting DMV was 0.88 (0.84-0.92). An SHD > 1.9 cm had a negative-predictive value of 99%. Multivariate analysis revealed that the SHD was an independent predictor of DMV.

Conclusions: In patients with obesity, SHD measured by a handheld ultrasound probe is an independent predictor of DMV and can accurately predict DMV. An SHD ≤ 1.9 cm can exclude DMV with 99% accuracy.

Background: Removal of intratracheal tumors is challenging due to the difficulty in securing a patent airway before surgery. We report a case of successful removal using jet ventilation with an injection-time-controllable manual jet ventilator.

Cases: A 3.3 cm-long intratracheal mass was located 5 cm below the vocal cords and obstructing 70%-80% of the trachea. Following induction, a rigid telescope under suspension laryngoscopy was used to guide the careful insertion of a hard and long catheter (inner diameter: 1.8 mm; outer diameter: 3 mm; length: 50 cm) beyond the tumor, enabling jet ventilation. The soft, lobulated mass was gradually excised using long forceps under endoscopic visualization. Anesthesia was maintained using total intravenous anesthesia. The operation lasted for 1 h and 45 min.

Conclusions: This device ensured oxygenation and ventilation during the endoscopic removal of a large intratracheal tumor. This approach highlights its utility in managing challenging airway obstructions.

Background: A simple superoposterior approach to thoracic transforaminal epidural injections (TFEIs) under ultrasonographic guidance was proposed to reduce zoster-associated pain (ZAP) involving multiple thoracic nerves and the likelihood of transitioning to postherpetic neuralgia (PHN).

Methods: Patients were prospectively enrolled. Primary endpoints were the burden of illness (BOI) scores and epidural contrast spread. Secondary endpoints included number of needle insertion attempts, sensory blockade, hemodynamic changes, procedure time, radiation dose, adverse events, rescue analgesics, PHN incidence and EuroQoL 5-Dimension scores.

Results: Thirty-five injections were performed in 27 patients. Median levels of cephalad-caudad epidural contrast spread were 3, 4, and 5 ml following injections of 2, 3, and 4 ml. Dorsal epidural spread was observed at levels 3, 4, and 5, whereas concurrent ventral spread was observed at levels 2, 3, and 4. BOI scores at 30-180 days significantly decreased (mean difference: -25.3, 95% CI [-57.4 to 6.6], P = 0.005), accounting for reduced rescue analgesic requirements and PHN occurrence and improved EuroQoL 5-Dimension scores. Median sensory blockade at 5 min post-procedure was at level 2, 3, and 4 after 2, 3, and 4 ml of therapeutic injectate. No significant hemodynamic changes were noted at 15 min post-injection. No serious adverse events were observed.

Conclusions: Spread of thoracic epidural contrast to all involved nerves was confirmed using this novel technique. Simplified needle placement reduced the technical difficulty and risk of complications. It might be a promising alternative approach for ZAP.