Effect of Minimum Bronchial Cuff Volume of Left-Sided Double-Lumen Tube for One-Lung Ventilation on the Change in Bronchial Cuff Pressure during Lateral Positioning in Thoracic Surgery: A Prospective Observational Study.

The minimum bronchial cuff volume (BCVmin) of a double-lumen tube (DLT) without air leaks during lung isolation may vary among individuals, and lateral positioning could increase the bronchial cuff pressure (BCP). We investigated the effect of initially established BCVmin (BCVi) on the change in BCP by lateral positioning. Seventy patients who underwent elective lung surgery were recruited and divided into two groups according to the BCVi obtained during anesthetic induction in each patient. Outcome analysis was conducted using data from 39 patients with a BCVi greater than 0 (BCVi > 0 group) and 27 with a BCVi of 0 (BCVi = 0 group). The primary outcome was a change in the value measured in the supine and lateral positions of the initially established BCP (BCPi; BCP at the time of BCVi injection), which was significantly larger in the BCVi > 0 group than in the BCVi = 0 group (1.5 (0.5-6.0) cmH2O vs. 0.0 (0.0-1.0) cmH2O; p < 0.001). BCVi was related to the left main bronchus (LMB) diameter (Spearman's rho = 0.676, p < 0.001) and the gap between the LMB diameter and the outer diameter of the bronchial cuff (Spearman's rho = 0.553, p < 0.001). Therefore, selecting a DLT size with a bronchial cuff that fits each patient's LMB may be useful in minimizing the change in BCP when performing lateral positioning during thoracic surgery. If the bronchial cuff requires unavoidable initial inflation, it is necessary to be aware that BCP may increase during lateral positioning and to monitor the BCP regularly if possible.

The principles of presenting statistical results using figures.

Tables and figures are commonly adopted methods for presenting specific data or statistical analysis results. Figures can be used to display characteristics and distributions of data, allowing for intuitive understanding through visualization and thus making it easier to interpret the statistical results. To maximize the positive aspects of figure presentation and increase the accuracy of the content, in this article, the authors will describe how to choose an appropriate figure type and the necessary components to include. Additionally, this article includes examples of figures that are commonly used in research and their essential components using virtual data.

Intraoperative development of pulmonary thromboembolism in a bedridden patient owing to a pelvic bone fracture with negative preoperative computed tomography pulmonary angiographic findings: A case report.

RATIONALE: Pulmonary thromboembolism (PTE) is a potentially life-threatening condition with high morbidity and mortality, and computed tomographic pulmonary angiography (CTPA) is an important diagnostic tool for patients in whom PTE is suspected; however, intraoperative PTE is very difficult to diagnose and often has a rapid clinical course. We experienced a case of intraoperative PTE with persistent tachycardia refractory to conventional treatments despite negative preoperative CTPA findings. PATIENT CONCERNS: A 53-year-old man with a pelvic bone fracture who had been on bed rest for 10 days underwent open reduction and internal fixation under general anesthesia. He remained tachycardic (heart rate of 120 beats/min) despite treatments with fluid resuscitation, analgesics, and beta-blockers. DIAGNOSES: Preoperative CTPA, computed tomography (CT) venography, and transthoracic echocardiography showed no signs of deep vein thrombosis and PTE. However, the levels of D-dimer were elevated. After the start of the surgery, tachycardia (heart rate between 100 and 110 beats/min) could not be treated with fluid resuscitation. Systolic blood pressure was maintained between 90 and 100 mm Hg using continuous infusion of phenylephrine. Ninety minutes after the surgery, systolic and diastolic blood pressures suddenly dropped from 100/60 to 30/15 mm Hg with a decrease in end-tidal carbon dioxide concentration from 29 to 13 mm Hg and development of atrial fibrillation. Arterial blood gas analysis revealed hypercapnia. Under the suspicion of PTE, cardiopulmonary resuscitation (CPR) was immediately initiated. Three CPR cycles raised the blood pressure back to 90/50 mm Hg with sinus tachycardia (115 beats/min). Transesophageal echocardiography showed right ventricular dysfunction and paradoxical septal motion. However, emboli were not found. Postoperative chest CT revealed massive PTE in both pulmonary arteries. INTERVENTIONS: Immediately, surgical embolectomy was performed uneventfully. OUTCOMES: The patient was discharged from the hospital 1 month later without any complications. LESSONS: The patient with moderate risk for PTE (heart rate > 95 beats/min and immobilization, surgery under general anesthesia, and lower limb fracture within 1 month) should be closely monitored and managed intraoperatively even if preoperative CTPA findings are negative. The development of PTE needs to be expected if tachycardia is refractory to conventional treatments.

Local anesthetic volume in ultrasound-guided interscalene block and opioid consumption during shoulder arthroscopic surgery: A retrospective comparative study.

ABSTRACT: Interscalene block (ISB) is commonly performed for regional anesthesia in shoulder surgery. Ultrasound-guided ISB enables visualization of the local anesthetic spread and a reduction in local anesthetic volume. However, little is known about the appropriate local anesthetic dose for surgical anesthesia without sedation or general anesthesia. The purpose of our study was to evaluate the appropriate local anesthetic volume by comparing intraoperative analgesics and hemodynamic changes in ISB in arthroscopic shoulder surgery.Overall, 1007 patients were divided into groups 1, 2, and 3 according to the following volume of local anesthetics: 10-19, 20-29, and 30-40 mL, respectively. The use of intraoperative analgesics and sedatives, and the reduction in intraoperative maximum blood pressure and heart rate were compared through retrospective analysis.Fentanyl was used in 55.6% of patients in group 1, which was significantly higher than in those groups 2 and 3 (22.3% and 30.7%, respectively); furthermore, it was also higher than those in groups 2 and 3 in dose-specific comparisons (P < .05). The percent of the maximum reduction in intraoperative systolic blood pressure and heart rate in group 3 was significantly higher than those in groups 1 and 2. Ephedrine administration was lower in group 2 than that in other groups (P < .05). The incidence of hypotensive bradycardic events was lowest (9.1%) at the local anesthetic volume of 24 mL as revealed by the quadratic regression analysis (R2 = 0.313, P = .003).Decreasing the local anesthetic volume to less than 20 mL for ultrasound-guided ISB as the sole anesthesia increases the opioid consumption during shoulder arthroscopic surgery. Local anesthetics >30 mL or increased opioid consumption with <20 mL of local anesthetics could increase the risk of cardiovascular instability intraoperatively. Our findings indicate that 24 mL of local anesthetic could be used to lower the incidence of hypotensive bradycardic events.

The principles of presenting statistical results: Table.

General medical journals such as the Korean Journal of Anesthesiology (KJA) receive numerous manuscripts every year. However, reviewers have noticed that the tables presented in various manuscripts have great diversity in their appearance, resulting in difficulties in the review and publication process. It might be due to the lack of clear written instructions regarding reporting of statistical results for authors. Therefore, the present article aims to briefly outline reporting methods for several table types, which are commonly used to present statistical results. We hope this article will serve as a guideline for reviewers as well as for authors, who wish to submit a manuscript to the KJA.

Changes in the Bronchial Cuff Pressure of Left-Sided Double-Lumen Endotracheal Tube by Lateral Positioning: A Prospective Observational Study.

Proper bronchial cuff pressure (BCP) is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. As positional change during endotracheal tube placement could alter cuff pressure, we aim to evaluate the change in BCP of DLT from the supine to the lateral decubitus position during thoracic surgery. A total of 69 patients aged 18-70 years who underwent elective lung surgery were recruited. BCP was measured at a series of time points in the supine and lateral decubitus positions after confirming the DLT placement. The primary outcome was change in the initial established BCP (BCPi), which is the maximum pressure at which the BCP did not exceed 40 cmH2O without air leak in the supine position, after lateral decubitus positioning. As the primary outcome, the BCPi increased from 25.4 ± 9.0 cmH2O in the supine position to 29.1 ± 12.2 cmH2O in the lateral decubitus position (p < 0.001). Out of the 69 participants, 43 and 26 patients underwent surgery in the left-lateral decubitus position (LLD group) and the right-lateral decubitus position (RLD group) respectively. In the LLD group, the BCPi increased significantly (p < 0.001) after lateral positioning and the beginning of surgery and the difference value, ∆BCPi, from supine to lateral position was significantly higher in the LLD group than in the RLD group (p = 0.034). Positional change from supine to lateral decubitus could increase the BCPi of DLT and the increase was significantly greater in LLD that in RLD.

Comparison of Pupillometry With Surgical Pleth Index Monitoring on Perioperative Opioid Consumption and Nociception During Propofol-Remifentanil Anesthesia: A Prospective Randomized Controlled Trial.

BACKGROUND: Intraoperative monitoring with pupillometry has shown promising results for nociception/antinociception balance monitoring. However, its benefits in clinical practice remain unproven. The aim of this study was to evaluate the efficacy of intraoperative pupillometry monitoring on intraoperative opioid consumption and postoperative pain compared to surgical pleth index (SPI), another widely investigated monitoring. METHODS: American Society of Anesthesiologists (ASA) I-II patients scheduled for elective laparoscopic cholecystectomy were included. This prospective, parallel-arm, single-center study was conducted in 2 steps. First, we evaluated the feasibility of using pupillometry and SPI monitoring compared with conventional hemodynamic monitoring. Next, a parallel-arm, double-blind randomized study compared the peak postoperative pain measured with numerical rating scale (NRS) from 0 (no pain) to 10 (extreme pain) as a primary outcome between pupillometry (pupillometry group, n = 43) and SPI monitoring (SPI group, n = 43) using Mann-Whitney U test. Secondary outcomes included intraoperative remifentanil consumption, postoperative opioid responsiveness (a decrease in NRS by ≥1 after fentanyl administrations), number of analgesic administrations, and opioid-related complications. RESULTS: In the preliminary study (n = 50), remifentanil consumption was less under pupillometry monitoring compared to SPI monitoring, and peak postoperative pain was lower under pupillometry compared to conventional monitoring. In the main study (n = 86), peak postoperative pain and intraoperative remifentanil consumption were lower in the pupillometry group (median [first to third quartile], 5 [4-6]; mean ± standard deviation [SD], 0.078 ± 0.019 µg·kg·minute) compared to the SPI group (7 [5-8] and 0.0130 ± 0.051 µg·kg·minute; P < .001), with the median difference in peak postoperative pain of -1 and its 95% confidence interval between -2 and -0.5. The pupillometry group had better responsiveness to fentanyl (84.6% vs 61.0%; P = .005) and lower number of analgesic administrations (2 [1-2] vs 2 [1-3]; P = .048) compared to the SPI group. CONCLUSIONS: Intraoperative pupillometry monitoring reduced intraoperative remifentanil consumption and postoperative pain. It may be an alternative option for intraoperative opioid control under general anesthesia in adult patients.

Tips for troublesome sample-size calculation.

Properly set sample size is one of the important factors for scientific and persuasive research. The sample size that can guarantee both clinically significant differences and adequate power in the phenomena of interest to the investigator, without causing excessive financial or medical considerations, will always be the object of concern. In this paper, we reviewed the essential factors for sample size calculation. We described the primary endpoints that are the main concern of the study and the basis for calculating sample size, the statistics used to analyze the primary endpoints, type I error and power, the effect size and the rationale. It also included a method of calculating the adjusted sample size considering the dropout rate inevitably occurring during the research. Finally, examples regarding sample size calculation that are appropriately and incorrectly described in the published papers are presented with explanations.

Airway management using laryngeal mask airway (LMA) in a patient in a lateral decubitus position: A case report.

RATIONALE: Airway management of patients in a lateral decubitus position (LDP), who cannot lie supine is challenging for anesthesiologists. In a previous study, laryngeal mask airway (LMA) was found to be superior to conventional endotracheal intubation in LDP. PATIENT CONCERNS: A 38-year-old man diagnosed with type I neurofibromatosis presented with pain caused by a large hematoma (28 × 8 cm) located in the left upper back. On arrival at the operating theater, he was in a right LDP because of the aggravation of pain in the supine position. DIAGNOSES: Laryngoscopy-guided endotracheal intubation was expected to be difficult in LDP. INTERVENTIONS: After the induction of anesthesia, a non-inflatable LMA was introduced into the laryngopharynx with the patient in LDP. He was then maneuvered into a supine position and removal of the LMA was followed by endotracheal intubation. OUTCOMES: The surgery for the removal of the hematoma was performed in a prone position. The airway intubated with an endotracheal tube was well maintained during the entire surgery. LESSONS: LMA is a useful device for airway management in patients in LDP who cannot lie supine.

Effects of C8 nerve root block during interscalene brachial plexus block on anesthesia of the posterior shoulder in patients undergoing arthroscopic shoulder surgery: study protocol for a prospective randomized parallel-group controlled trial.

BACKGROUND: A classical approach to produce interscalene brachial plexus block (ISBPB) consistently spares the posterior aspect of the shoulder and ulnar sides of the elbow, forearm, and hand, which are innervated by the lower trunk of the brachial plexus (C8-T1). As an alternative to the classical approach, a caudal approach to ISBPB successfully produces anesthesia of the ulnar sides of the elbow, forearm, and hand. However, its beneficial effects on anesthesia in the posterior aspect of the shoulder have not been investigated. In addition, the C8 nerve root is not routinely selectively blocked during ISBPB. Therefore, we will compare the C5 to C7 and C5 to C8 nerve root blocks during a caudal approach to ISBPB to assess the clinical benefit of C8 nerve blocks for the surgical anesthesia of the posterior aspect of the shoulder. METHODS/DESIGN: In this prospective parallel-group single-blind randomized controlled trial, 74 patients scheduled to undergo arthroscopic shoulder surgery under ISBPB are randomly allocated to receive the C5 to C7 or C5 to C8 nerve root block at a 1:1 ratio. The primary outcome is pain intensity, which is rated as 0 (no pain), 1 (mild pain), or 2 (severe pain), during the introduction of a posterior portal into the glenohumeral joint. The secondary outcomes are (1) the extent of the ipsilateral sensory, motor, hemidiaphragmatic, and stellate ganglion blockade, (2) changes in the results of a pulmonary function test, (3) incidence of complications related to ISBPB, (4) postoperative numerical pain rating scale scores, (5) patients' satisfaction with the ISBPB, (6) dose and frequency of analgesic use, and (7) incidence of conversion to general anesthesia. DISCUSSION: This study is the first to evaluate the beneficial effects of the C8 nerve root block during ISBPB, which has rarely been performed due to the technical challenge in visualizing and blocking the C8 nerve root. It is expected that a C8 nerve root block performed during ISBPB will provide sufficient surgical anesthesia of the posterior aspect of the shoulder, which cannot be achieved by a classical approach to ISBPB. TRIAL REGISTRATION: ClicnicalTrials.gov, NCT03487874 . Registered on 4 April 2018.

Multicollinearity and misleading statistical results.

Multicollinearity represents a high degree of linear intercorrelation between explanatory variables in a multiple regression model and leads to incorrect results of regression analyses. Diagnostic tools of multicollinearity include the variance inflation factor (VIF), condition index and condition number, and variance decomposition proportion (VDP). The multicollinearity can be expressed by the coefficient of determination (Rh2) of a multiple regression model with one explanatory variable (Xh) as the model's response variable and the others (Xi [i ≠ h]) as its explanatory variables. The variance (σh2) of the regression coefficients constituting the final regression model are proportional to the VIF. Hence, an increase in Rh2 (strong multicollinearity) increases σh2. The larger σh2 produces unreliable probability values and confidence intervals of the regression coefficients. The square root of the ratio of the maximum eigenvalue to each eigenvalue from the correlation matrix of standardized explanatory variables is referred to as the condition index. The condition number is the maximum condition index. Multicollinearity is present when the VIF is higher than 5 to 10 or the condition indices are higher than 10 to 30. However, they cannot indicate multicollinear explanatory variables. VDPs obtained from the eigenvectors can identify the multicollinear variables by showing the extent of the inflation of σh2 according to each condition index. When two or more VDPs, which correspond to a common condition index higher than 10 to 30, are higher than 0.8 to 0.9, their associated explanatory variables are multicollinear. Excluding multicollinear explanatory variables leads to statistically stable multiple regression models.

Comparing the placement of a left-sided double-lumen tube via fiberoptic bronchoscopy guidance versus conventional intubation using a Macintosh laryngoscope, to reduce the incidence of malpositioning: study protocol for a randomized controlled pilot trial.

BACKGROUND: A fiberoptic bronchoscope (FOB) is commonly used to identify the proper placement of a double-lumen endotracheal tube (DLT) for good lung isolation during thoracic surgery. We hypothesized that the FOB-guided method for DLT placement composed of tracheal intubation under initial guidance by a FOB via the bronchial lumen and subsequent selective left-bronchial intubation could be used to reduce the incidence of DLT malposition and reduce the time required for completion of DLT placement and confirmation of proper DLT position during intubation using a left-sided DLT, in comparison to the conventional method under direct laryngoscopy using a Macintosh laryngoscope. METHODS/DESIGN: In this randomized controlled pilot trial, 50 patients, aged 18-70 years, scheduled for elective thoracic surgery will be recruited and randomly assigned to two groups according to the method of DLT placement: a FOB-guided method (F) group and a conventional method (C) group. Regardless of the group, the DLT placement processes will be followed by subsequent confirmation processes, using a FOB. If the DLT is misplaced, the position would be corrected. The primary outcome is the incidence of DLT malpositioning observed via a FOB during confirmation after DLT placement. The secondary outcomes consist of the time required to achieve the entire DLT intubation process, which is the sum of the duration of DLT placement and the duration of confirmation of the proper position, the incidence of failed tracheal intubation on the first and second attempt, and complications associated with the intubation process. DISCUSSION: This pilot study was designed as the first randomized controlled trial to confirm our hypothesis. This should provide information for a further full-scale trial, and the outcomes of the study should provide clinical evidence on the usefulness of the FOB-guided method for DLT placement, in comparison to the conventional method. TRIAL REGISTRATION: Clinical Research Information Service; CRIS, ID: KCT0002663 . Retrospectively registered on 24 January 2018.

Assessment of P values for demographic data in randomized controlled trials.

In a large number of randomized controlled trials, researchers provide P values for demographic data, which are commonly reported in table 1 of the article for the purpose of emphasizing the lack of differences between or among groups. As such, the authors intend to demonstrate that statistically insignificant P values in the demographic data confirm that group randomization was adequately performed. However, statistically insignificant P values do not necessarily reflect successful randomization. It is more important to rigorously establish a plan for statistical analysis during the design and planning stage of the study, and to consider whether any of the variables included in the demographic data could potentially affect the research results. If a researcher rigorously designed and planned a study, and performed it accordingly, the conclusions drawn from the results would not be influenced by P values, regardless of whether they were significant. In contrasts, imbalanced variables could affect the results after variance controlling, even though whole study process are well planned and executed. In this situation, the researcher can provide results with both the initial method and a second stage of analysis including such variables. Otherwise, for brief conclusions, it would be pointless to report P values in a table simply listing baseline data of the participants.

Assessment of risk of bias in quasi-randomized controlled trials and randomized controlled trials reported in the Korean Journal of Anesthesiology between 2010 and 2016.

Bias affects the true intervention effect in randomized controlled trials (RCTs), making the results unreliable. We evaluated the risk of bias (ROB) of quasi-RCTs or RCTs reported in the Korean Journal of Anesthesiology (KJA) between 2010 and 2016. Six kinds of bias (selection, performance, detection, attrition, reporting, and other biases) were evaluated by determining low, unclear, or high ROB for eight domains (random sequence generation, allocation concealment, blinding of participants, blinding of personnel, blinding of outcome assessment, incomplete outcome data, selective reporting, and other bias) according to publication year. We identified 296 quasi-RCTs or RCTs. Random sequence generation was performed better than allocation concealment (51.7% vs. 20.9% for the proportion of low ROB, P < 0.001 and P = 0.943 for trend, respectively). Blinding of outcome assessment was superior to blinding of participants and personnel (42.9% vs. 15.5% and 23.0% for the proportion of low ROB, P = 0.026 vs. P = 0.003 and 0.896 for trend, respectively). Handling of incomplete outcome data was performed best with the highest proportion of low ROB (84.8%). Selective reporting had the lowest proportion of low ROB (4.7%). However, the ROB improved year by year (P < 0.001 for trend). Authors and reviewers should consider allocation concealment after random sequence generation, blinding of participants and personnel, and full reporting of results to improve the quality of RCTs submitted hereafter for publication in the KJA.

Statistical data preparation: management of missing values and outliers.

Missing values and outliers are frequently encountered while collecting data. The presence of missing values reduces the data available to be analyzed, compromising the statistical power of the study, and eventually the reliability of its results. In addition, it causes a significant bias in the results and degrades the efficiency of the data. Outliers significantly affect the process of estimating statistics (e.g., the average and standard deviation of a sample), resulting in overestimated or underestimated values. Therefore, the results of data analysis are considerably dependent on the ways in which the missing values and outliers are processed. In this regard, this review discusses the types of missing values, ways of identifying outliers, and dealing with the two.

Central limit theorem: the cornerstone of modern statistics.

According to the central limit theorem, the means of a random sample of size, n, from a population with mean, µ, and variance, σ2, distribute normally with mean, µ, and variance, [Formula: see text]. Using the central limit theorem, a variety of parametric tests have been developed under assumptions about the parameters that determine the population probability distribution. Compared to non-parametric tests, which do not require any assumptions about the population probability distribution, parametric tests produce more accurate and precise estimates with higher statistical powers. However, many medical researchers use parametric tests to present their data without knowledge of the contribution of the central limit theorem to the development of such tests. Thus, this review presents the basic concepts of the central limit theorem and its role in binomial distributions and the Student's t-test, and provides an example of the sampling distributions of small populations. A proof of the central limit theorem is also described with the mathematical concepts required for its near-complete understanding.

Pulsed radiofrequency treatment of the superior hypogastric plexus in an interstitial cystitis patient with chronic pain and symptoms refractory to oral and intravesical medications and bladder hydrodistension: A case report.

RATIONALE: A variety of therapeutic modalities are available for the treatment of interstitial cystitis. However, among them, the less invasive therapies are usually ineffective, whereas the invasive ones carry potential risks of serious side effects and complications. Pulsed radiofrequency (PRF) treatment of the superior hypogastric plexus may be an alternative to conventional treatments, as it provides nondestructive neuromodulation to the superior hypogastric plexus, which transmits the majority of pain signals from the pelvic viscera. PATIENT CONCERNS: For 7 years, a 35-year-old female patient had been experiencing lower abdominal pain provoked by urinary bladder filling, perivulvar pain developing spontaneously during sleep or upon postural change, urinary urgency and frequency with 15- to 60-min intervals between urinations, and nocturia with 10 voids per night. Hydrodistension of the bladder, monthly intravesical administration of sterile sodium chondroitin sulfate, and oral medications including gabapentin and pentosan polysulfate had not been effective in managing the pain and symptoms. DIAGNOSES AND INTERVENTIONS: Given the satisfactory result of a diagnostic block of the superior hypogastric plexus, 2 sessions of PRF treatment of the superior hypogastric plexus, which applied radiofrequency pulses with a pulse frequency of 2 Hz and a pulse width of 20 ms for 120 s twice per session to maintain the tissue temperature near the electrode at 42°C, were performed at a 6-month interval. OUTCOMES: This treatment relieved the pain and symptoms for 2 years and 6 months. LESSONS: PRF treatment of the superior hypogastric plexus results in long-term improvements in the pain and symptoms associated with interstitial cystitis.

The anhepatic phase extended by temporary portocaval shunt does not affect anesthetic sensitivity and postoperative cognitive function: A case-control study.

Temporary portocaval shunt (TPCS) prolongs the duration of the anhepatic phase, during which anesthetic sensitivity is highest among the 3 phases of living donor liver transplantation (LDLT). Cognitive dysfunction has been associated with increased anesthetic sensitivity and poor hepatic function. Therefore, we assessed anesthetic sensitivity to desflurane and perioperative cognitive function in patients undergoing LDLT, in whom the duration of the anhepatic phase was extended by TPCS to test the hypothesis that the prolonged anhepatic phase increases anesthetic sensitivity and causes postoperative cognitive decline.This case-control study was conducted in 67 consecutive patients undergoing LDLT from February 2014 to January 2016. Anesthesia was maintained at a 0.6 end-tidal age-adjusted minimum alveolar concentration of desflurane. The bispectral index (BIS) was maintained at less than 60 and averaged at 1-minute intervals. The mini-mental state examination (MMSE-KC) was performed 1 day before and 7 days after the LDLT. All parameters were compared between the patients undergoing TPCS (TPCS group) and the remaining patients (non-TPCS group).TPCS was performed in 16 patients (24%). TPCS prolonged the duration of the anhepatic phase (125.9 ±â€Š29.4 vs 54.9 ±â€Š20.5 minutes [mean ±â€Šstandard deviation], P < 0.0001). The averaged BIS values during the 3 phases were comparable between the 2 groups. No significant interval changes in the averaged BIS values were observed during the 3 consecutive phases. Similarly, there were no significant differences in MMSE-KC score assessed 1 day before and 7 days after LDLT between the 2 groups. The preoperative MMSE-KC scores were unchanged postoperatively in the 2 groups.The extension of the anhepatic phase did not affect anesthetic sensitivity and postoperative cognitive function.

Liver graft hyperperfusion in the early postoperative period promotes hepatic regeneration 2 weeks after living donor liver transplantation: A prospective observational cohort study.

Hepatic regeneration is essential to meet the metabolic demands of partial liver grafts following living donor liver transplantation (LDLT). Hepatic regeneration is promoted by portal hyperperfusion of partial grafts, which produces shear stress on the sinusoidal endothelium. Hepatic regeneration is difficult to assess within the first 2 weeks after LDLT as the size of liver graft could be overestimated in the presence of postsurgical graft edema. In this study, we evaluated the effects of graft hyperperfusion on the rate of hepatic regeneration 2 weeks after LDLT by measuring hepatic hemodynamic parameters. Thirty-six patients undergoing LDLT were enrolled in this study. Hepatic hemodynamic parameters including peak portal venous flow velocity (PVV) were measured using spectral Doppler ultrasonography on postoperative day 1. Subsequently, we calculated the ratio of each velocity to 100 g of the initial graft weight (GW) obtained immediately after graft retrieval on the day of LDLT. Ratios of GW to recipient weight (GRWR) and to standard liver volume (GW/SLV) were also obtained. The hepatic regeneration rate was defined as the ratio of the regenerated volume measured using computed tomographic volumetry at postoperative week 2 to the initial GW. Correlations of the hemodynamic parameters, GRWR, and GW/SLV with the hepatic regeneration rate were assessed using a linear regression analysis. The liver grafts regenerated to approximately 1.7 times their initial GW (1.7 ±â€Š0.3 [mean ±â€Šstandard deviation]). PVV/100 g of GW (r = 0.224, ß1 [slope coefficient] = 2.105, P = 0.004) and velocities of the hepatic artery and vein per 100 g of GW positively correlated with the hepatic regeneration rate, whereas GRWR (r = 0.407, ß1 = -81.149, P < 0.001) and GW/SLV (r = 0.541, ß1 = -2.184, P < 0.001) negatively correlated with the hepatic regeneration rate. Graft hyperperfusion demonstrated by increased hepatic vascular velocities and a small-sized graft in the early postoperative period contributes to hepatic regeneration 2 weeks after LDLT.