Ho-Geol Ryu

Epinephrine and phenylephrine pretreatments for preventing postreperfusion syndrome during adult liver transplantation

Acute hypotension after reperfusion of the liver graft occurs frequently during liver transplantation. A randomized, prospective trial was performed to test the effects of epinephrine and phenylephrine pretreatments for attenuating postreperfusion syndrome (PRS). Ninety‐three adult liver recipients were randomly allocated to receive an intravenous bolus of 10 μg of epinephrine, 100 μg of phenylephrine, or normal saline (the control group) at the time of graft reperfusion. The occurrence of PRS, the use of vasoactive drugs, and the postoperative courses were compared. The epinephrine and phenylephrine groups showed PRS less frequently (39% and 48%) than the control group (77%, P = 0.006) as well as higher mean arterial pressures (MAPs) immediately after reperfusion (P < 0.05). An overshoot of MAP was observed in one‐third of the pretreated patients with minimal heart rate changes. Only 2 patients in each pretreatment group showed an increase in MAP that was greater than 20% of the baseline value. The intraoperative epinephrine and dopamine requirements were significantly lower in both pretreatment groups. Perioperative laboratory data, postoperative stays, and in‐hospital mortality rates were similar for the 3 groups. In conclusion, pretreatment with 10 μg of epinephrine or 100 μg of phenylephrine significantly reduces the occurrence of PRS and vasopressor requirements without immediate or delayed adverse effects in adult liver transplantation. Liver Transpl, 2012.

Dexmedetomidine confers neuroprotection against transient global cerebral ischemia/reperfusion injury in rats by inhibiting inflammation through inactivation of the TLR-4/NF-κB pathway

Dexmedetomidine (DXM) has anti-inflammatory effects, which is considered an important mechanism of DXM-induced neuroprotection from cerebral ischemia/reperfusion injury. We determined whether the anti-inflammatory effects of DXM are associated with inhibition of the toll-like receptor (TLR)-4/nuclear factor kappa B (NF-κB) pathway in a rat model of transient global cerebral ischemia/reperfusion injury. Fifty rats were randomly assigned to one of five groups (10 rats/group): Group S received no treatment; Group C underwent transient global ischemia (10min); Group D received DXM 30min before ischemia; Group R received resatorvid, a selective TLR-4 antagonist, 30min before ischemia; and Group RD received resatorvid and DXM 30min before ischemia. The numbers of necrotic and apoptotic cells and the levels of TLR-4, NF-κB, and caspase-3 were assessed 1day after ischemia, and pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) were measured before ischemia and 2, 6, and 24h thereafter. The necrotic and apoptotic cell counts and levels of TLR-4, NF-κB, and caspase-3 were higher in Group C than in other groups. TNF-α were higher in Group C than in other groups 2h after ischemia, whereas IL-6 were higher in Group C 6h after ischemia. IL-1β was higher in Group C than in Group D 6 and 24h after ischemia. Our findings suggest that the anti-inflammatory action of DXM via inactivation of the TLR-4/NF-κB pathway, in part, may explain DXM-induced neuroprotection after cerebral ischemia.

Effect of the bevel direction of puncture needle on success rate and complications during internal jugular vein catheterization

Objective: Artery puncture and hematoma formation are the most common immediate complications during internal jugular vein catheterization. This study was performed to assess whether the bevel-down approach of the puncture needle decreases the incidence of posterior venous wall damage and hematoma formation during internal jugular vein catheterization. Design: Prospective, randomized, controlled study. Setting: A university-affiliated hospital. Patients: Three hundred thirty-eight patients for scheduled for thoracic surgery requiring central venous catheterization in the right internal jugular vein. Interventions: Patients requiring internal jugular vein catheterization were enrolled and randomized to either the bevel-down group (n = 169) or the bevel-up group (n = 169). All patients were placed in the Trendelenburg position with the head turned to the left. After identifying the right internal jugular vein with ultrasound imaging, a double-lumen central venous catheter was inserted using the modified Seldinger technique. Venous entry of the needle was recognized by return of venous blood during needle advance or withdrawal. The internal jugular vein was assessed cross-sectionally and longitudinally after catheterization to identify any complications. A p value of <.05 was considered to be statistically significant. Measurements and Main Results: There was no difference in the incidence of the puncture-on-withdrawal between the two groups (37 of 169 in the bevel-down group and 25 of 169 in the bevel-up group). However, the incidence of posterior hematoma formation was lower in the bevel-down group (six of 169 vs. 17 of 169, p = .031). Additionally, there was less incidence of the posterior hematoma formation associated with puncture-on-withdrawal in the bevel-down group (six of 37 vs. 11 of 25, p = .034). Conclusions: The bevel-down approach of the right internal jugular vein may decrease the incidence of posterior venous wall damage and hematoma formation compared with the bevel-up approach, which implicates a reduced probability of carotid artery puncture with the bevel-down approach during internal jugular vein catheterization.

Use of a neck brace minimizes double-lumen tube displacement during patient positioning.

PurposeWhen patients are moved from the supine to the lateral decubitus position, the double-lumen endobronchial tube (DLT) is often displaced. The aim of this study was to determine whether a DLT is displaced when there are no movements of the head and neck.MethodsOne hundred patients scheduled for elective thoracic surgery were randomly divided into control and brace groups. Only a left-sided DLT was used during the study. All patients in the brace group wore a neck collar before the positional change. Using a fibreoptic bronchoscope, the distance from the tracheal opening to the main carina and from the bronchial opening to the bronchial carina was measured in the supine and lateral decubitus positions.ResultsDisplacement of the DLT (mean ± SD) during a change from the supine to the lateral decubitus position was greater in the control group (6.3 ± 5.5 mm in the trachea; 2.4 ± 3.6 mm in the bronchus) than in the brace group (2.2 ± 3.9 mm in the trachea; 0.6 ± 3.1 mm in the bronchus); (P < 0.001). The incidence of clinically significant displacement, greater than 5 mm from the initial correct position, was higher in the control group than in the brace group (48% vs 12%, P < 0.001).ConclusionBy restricting head and neck movements with a neck brace, the DLT displacement could be minimized while positioning patients for thoracotomy. The main cause of the DLT displacement during lateral positioning appears to be related to movement of the head and neck.ObjectifQuand les patients sont changés de position, du décubitus dorsal à latéral, le tube endobronchique à double lumière (TDL) est souvent déplacé. Notre but était de découvrir si un TDL est déplacé quand il n’y a aucun mouvement de la tête et du cou.MéthodeCent patients devant subir une intervention chirurgicale thoracique réglée ont été répartis en groupes témoin et collet cervical (CC). Seul un TDL gauche a été utilisé. Tous les patients du groupe CC portaient un collet cervical avant le changement de position. à l’aide d’un fibroscope bronchique, la distance entre l’ouverture de la trachée et la carène principale et entre l’ouverture bronchique et la carène bronchique a été mesurée en décubitus dorsal et latéral.RésultatsLe déplacement du TDL (moyenne ± écart type) pendant un changement de position, du décubitus dorsal à latéral, a été plus grand dans le groupe témoin (6,3 ± 5,5 mm dans la trachée; 2,4 ± 3,6 mm dans la bronche) que dans le groupe CC (2,2 ± 3,9 mm dans la trachée ; 0,6 ± 3,1 mm dans la bronche); (P < 0,001). L’incidence d’un déplacement cliniquement significatif, plus grand que 5 mm de la position initiale correcte, a été plus élevée dans le groupe témoin que dans le groupe CC (48 % vs12 %, P < 0,001). asConclusionEn restreignant les mouvements de la tête et du cou avec un collet cervical, le déplacement du TDL peut être minimisé quand on installe les patients pour la thoracotomie. La principale cause de déplacement du TDL chez le patient en décubitus latéral semble reliée au mouvement de la tête et du cou.

Association Between Perioperative Hyperglycemia or Glucose Variability and Postoperative Acute Kidney Injury After Liver Transplantation: A Retrospective Observational Study.

BACKGROUND: Glucose control can be difficult in the intraoperative and immediate postoperative period of liver transplantation. Hyperglycemia and glucose variability have been associated with acute kidney injury (AKI) in critically ill patients. We performed a retrospective study to test the hypothesis that perioperative glucose levels represented by time-weighted average glucose levels and glucose variability are independently associated with the incidence of postoperative AKI in patients undergoing liver transplantation. METHODS: On the basis of blood glucose levels during liver transplantation and the initial 48 hours postoperatively, adult liver transplant recipients were classified into 4 groups according to their time-weighted average glucose: normoglycemia (80–200 mg/dL), mild hyperglycemia (200–250 mg/dL), moderate hyperglycemia (250–300 mg/dL), and severe hyperglycemia (>300 mg/dL) group. Patients were also classified into quartiles depending on their glucose variability, defined as the standard deviation of glucose measurements. The primary outcome was postoperative AKI. RESULTS: AKI after liver transplantation was more common in the patients with greater perioperative glucose variability (first versus third quartile; OR, 2.47 [95%CI, 1.22–5.00], P = .012; first versus fourth quartile; OR, 2.16 [95% CI, 1.05–4.42], P = .035). CONCLUSIONS: Our study suggests that increased perioperative glucose variability, but not hyperglycemia, is independently associated with increased risk of postoperative AKI in liver transplantation recipients.

Prophylactic milrinone during OPCAB of posterior vessels: implication in angina patients taking β-blockers

OBJECTIVE To determine whether a phosphodiesterase type 3 inhibitor can improve hemodynamics during off-pump coronary artery bypass grafting (OPCAB) of posterior vessels in patients on beta(1)-adrenoreceptor blockers. METHODS Thirty patients scheduled for OPCAB of the obtuse marginal artery (OM), and taking atenolol 100 mg a day were randomized in a double-blind manner to receive either milrinone or placebo. Hemodynamic data were obtained after induction, before pericardial incision, during left anterior descending artery grafting, during OM grafting, and after removal of the stabilizer. During the OM grafting, dopamine was infused when the cardiac index (CI) decreased below 2.0 L/min/m(2), and phenylephrine was infused to maintain the arterial pressure with a CI above 2.0 L/min/m(2). RESULTS During OM anastomosis, there were significant differences in CI (milrinone [M] = +7.7%, control [C] = -13.7%, p=0.01), SVI (M=-21.5%, C=-35.8%, p=0.03), SvO(2) (M=-2.6%, C=-8.9%, p=0.02), and SVR (M=-28.1%, C=+1.1%, p=0.01) between the two groups, in terms of percentage change from baseline value. Dopamine was required more frequently and at a higher dose in the control group (M=13%, 5.0 microg/kg/min; C=67%, 10.1 microg/kg/min, p<0.05). Phenylephrine was infused in 33% of the patients in the milrinone group compared to 13% in the control group (p>0.05). CONCLUSIONS Prophylactic milrinone improves CI, SVI and SvO(2) reducing the need for high doses of dopamine during OM anastomosis in patients taking atenolol. Therefore, it can be used as an alternative to dopamine improving hemodynamics and organ perfusion during OPCAB of posterior vessels in patients on beta(1)-blockers.

A randomised controlled trial comparing incentive spirometry with the Acapella® device for physiotherapy after thoracoscopic lung resection surgery†

Lung resection surgery has been associated with numerous postoperative complications. Seventy‐eight patients scheduled for elective video‐assisted thoracoscopic lung resection were randomly assigned to receive standard postoperative care with incentive spirometry or standard care plus positive vibratory expiratory pressure treatment using the Acapella® device. There was no significant difference between incentive spirometry and the Acapella device in the primary outcome, forced expiratory volume in 1 s, on the third postoperative day, mean (SD) 53% (16%) vs 59% (18%) respectively, p = 0.113. Patients treated with both devices simultaneously found incentive spirometry to be less comfortable compared with the Acapella device, using a numeric rating scale from 1 to 5 with lower scores indicating higher comfort, median (IQR [range]) 3 (2–3 [2–4]) vs 1 (1–2 [1–3]) respectively, p < 0.001. In addition, 37/39 patients (95%) stated a clear preference for the Acapella device. Postoperative treatment with the Acapella device did not improve pulmonary function after thoracoscopic lung resection surgery compared with incentive spirometry, but it may be more comfortable to use.

Utility of the laryngeal handshake method for identifying the cricothyroid membrane

The cricothyroid membrane is the most commonly accessed location for invasive surgical airway. Although the laryngeal handshake method is recommended for identifying the cricothyroid membrane, there is no clinical data regarding the utility of the laryngeal handshake method in cricothyroid membrane identification. The objective of this study was to compare the accuracy of cricothyroid membrane identification between the laryngeal handshake method and simple palpation.

Prediction of bispectral index during target-controlled infusion of propofol and remifentanil: A deep learning approach

Background: The discrepancy between predicted effect-site concentration and measured bispectral index is problematic during intravenous anesthesia with target-controlled infusion of propofol and remifentanil. We hypothesized that bispectral index during total intravenous anesthesia would be more accurately predicted by a deep learning approach. Methods: Long short-term memory and the feed-forward neural network were sequenced to simulate the pharmacokinetic and pharmacodynamic parts of an empirical model, respectively, to predict intraoperative bispectral index during combined use of propofol and remifentanil. Inputs of long short-term memory were infusion histories of propofol and remifentanil, which were retrieved from target-controlled infusion pumps for 1,800 s at 10-s intervals. Inputs of the feed-forward network were the outputs of long short-term memory and demographic data such as age, sex, weight, and height. The final output of the feed-forward network was the bispectral index. The performance of bispectral index prediction was compared between the deep learning model and previously reported response surface model. Results: The model hyperparameters comprised 8 memory cells in the long short-term memory layer and 16 nodes in the hidden layer of the feed-forward network. The model training and testing were performed with separate data sets of 131 and 100 cases. The concordance correlation coefficient (95% CI) were 0.561 (0.560 to 0.562) in the deep learning model, which was significantly larger than that in the response surface model (0.265 [0.263 to 0.266], P < 0.001). Conclusions: The deep learning model–predicted bispectral index during target-controlled infusion of propofol and remifentanil more accurately compared to the traditional model. The deep learning approach in anesthetic pharmacology seems promising because of its excellent performance and extensibility.

Reliability of Point-of-care Hematocrit Measurement During Liver Transplantation

BACKGROUND: Although point-of-care (POC) analyzers are commonly used during liver transplantation (LT), the accuracy of hematocrit measurement using a POC analyzer has not been evaluated. In this retrospective observational study, we aimed to evaluate the accuracy of hematocrit measurement using a POC analyzer and identify potential contributors to the measurement error and their influence on mistransfusion during LT. METHODS: We retrospectively collected 6461 pairs of simultaneous intraoperative hematocrit measurements using POC analyzers and laboratory devices during LTs in 901 patients. The agreement of hematocrit measurements was assessed using Bland-Altman analysis for repeated measurements, while the incidence and magnitude of hematocrit measurement error were compared among 16 different laboratory abnormality categories. A generalized estimating equation analysis was performed to identify potential contributors to falsely low-measured POC hematocrit. Additionally, we defined potential “overtransfusion” in the case when POC hematocrit was <20% and laboratory hematocrit was ≥20% and investigated its association with intraoperative transfusion. RESULTS: The POC hematocrit measurements were falsely lower than the laboratory hematocrit measurements in 70.3% (4541/6461) of pairs. The median (interquartile range) of hematocrit measurement error was −1.20 (−2.60 to 0.20). Bland-Altman analysis showed that 24.5% (1583/6461) of the errors were outside our a priori defined clinically acceptable limits of ±3%. The incidence of falsely low-measured hematocrit was significantly higher with the presence of concomitant hypoalbuminemia and hypoproteinemia. Hypoalbuminemia combined with hyperglycemia showed significantly larger hematocrit measurement error. Hypoalbuminemia, hypoproteinemia, and hyperglycemia were predictors of falsely low-measured hematocrit. Furthermore, the overtransfusion group showed larger amount of transfusion than the adequately transfused group, with a median difference of 2 units (95% confidence interval [0–4], P = .039), despite similar amount of blood loss. CONCLUSIONS: Hematocrit measured using the POC device tends to be lower than the laboratory hematocrit measured during LT. Commonly encountered laboratory abnormalities during LT include hypoalbuminemia, hypoproteinemia, and hyperglycemia, which may contribute to falsely low-measured POC hematocrit. Careful consideration of these confounders may help reduce overtransfusion that occurs due to falsely low-measured POC hematocrit.