Hyun Sik Chung

Awareness and recall during general anesthesia.

Anesthesia awareness is defined as both consciousness and recall of surgical events. New research has been conducted out to test this phenomenon. However, testing methods have not proven reliable, including those using devices based on electroencephalographic techniques to detect and prevent intraoperative awareness. The limitations of a standard intraoperative brain monitor reflect our insufficient understanding of consciousness. Moreover, patients who experience an intraoperative awareness can develop serious post-traumatic stress disorders that should not be overlooked. In this review, we introduce the incidence of intraoperative awareness during general anesthesia and discuss the mechanisms of consciousness, as well as risk factors, various monitoring methods, outcome and prevention of intraoperative awareness.

Perioperative Assessment of Terlipressin Infusion during Living Donor Liver Transplantation

OBJECTIVE: To investigate the safety and efficacy of infusion of terlipressin during living donor liver transplantation (LDLT). METHODS: Patients undergoing LDLT with low systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) (n = 41) were randomly allocated into control (n = 20) and terlipressin groups (n = 21). Terlipressin was infused at 1.0 – 4.0 μg/kg per h in the terlipressin group during surgery. Controls received generally accepted inotropic and vasopressor agents. RESULTS: Terlipressin infusion induced significantly higher SVRI and PVRI at 60 min after drug infusion, produced significantly greater hourly urine output during the anhepatic phase, and was related to significantly shorter stays in the postoperative intensive care unit (ICU) compared with control treatment (mean ± SD ICU stay 5.7 ± 1.5 versus 6.9 ± 1.5 days, respectively). Patients given a terlipressin infusion > 2.0 μg/kg per h during the preanhepatic phase had a median ICU stay of < 6 days (sensitivity 90.0%; specificity 89.0%). CONCLUSIONS: Terlipressin infusion improved low SVRI and PVRI during LDLT and may have contributed to better renal function and shorter ICU stays.

Effects of magnesium pretreatment on the levels of T helper cytokines and on the severity of reperfusion syndrome in patients undergoing living donor liver transplantation

OBJECTIVES Magnesium has protective effects in ischaemia-reperfusion injury, and is involved in immunomodulation. We investigated the effects of magnesium pretreatment on the secretion of T helper (Th) cytokines and on the severity of post-reperfusion syndrome (PRS) in patients undergoing living donor liver transplantation (LDLT). METHODS forty patients were allocated to two groups of 20 (magnesium and saline groups). Blood samples for cytokine analysis were collected before infusion of the study solution at the end of anhepatic phase (time point 1), as well as five min and 30 min after allograft reperfusion (time points 2 and 3, respectively). Levels of cytokines were quantified using a sandwich enzyme immunoassay test kit. RESULTS The duration of PRS was shorter in the magnesium group (p = 0.038). The level of interferon (IFN)-γ released from Th1 was lower in the magnesium group at time point 3 (p = 0.009). Of the cytokines released from Th2 cells, interleukin (IL)-6 was present in higher concentrations in the magnesium group at time points 2 and 3 (p<0.05). The concentrations of IL-4 and IL-10, which were secreted from Th2 cells, were also higher in the magnesium group at time point 3 (p<0.05). The IFN-γ /IL-6, IFN-γ /IL-4 and IFN-γ /IL-10 ratios were lower in the magnesium group after allograft reperfusion. CONCLUSIONS Magnesium pretreatment attenuated PRS and reinforced Th2 cell activity, shifting the Th1-to-Th2 cytokine balance towards Th2 in patients undergoing LDLT.

Sluggish decline in a post-transplant model for end-stage liver disease score is a predictor of mortality in living donor liver transplantation

Background The pre-transplant model for end-stage liver disease (pre-MELD) score is controversial regarding its ability to predict patient mortality after liver transplantation (LT). Prominent changes in physical conditions through the surgery may require a post-transplant indicator for better mortality prediction. We aimed to investigate whether the post-transplant MELD (post-MELD) score can be a predictor of 1-year mortality. Methods Perioperative variables of 269 patients with living donor LT were retrospectively investigated on their association with 1-year mortality. Post-MELD scores until the 30th day and their respective declines from the 1st day post-MELD score were included along with pre-MELD, acute physiology and chronic health evaluation (APACHE) II, and sequential organ failure assessment (SOFA) scores on the 1st post-transplant day. The predictive model of mortality was established by multivariate Coxs proportional hazards regression. Results The 1-year mortality rate was 17% (n = 44), and the leading cause of death was graft failure. Among prognostic indicators, only post-MELD scores after the 5th day and declines in post-MELD scores until the 5th and 30th day were associated with mortality in univariate analyses (P < 0.05). After multivariate analyses, declines in post-MELD scores until the 5th day of less than 5 points (hazard ratio 2.35, P = 0.007) and prolonged mechanical ventilation ≥24 hours were the earliest independent predictors of 1-year mortality. Conclusions A sluggish decline in post-MELD scores during the early post-transplant period may be a meaningful prognostic indicator of 1-year mortality after LT.

Practice guidelines for propofol sedation by non-anesthesiologists: The Korean Society of Anesthesiologists Task Force recommendations on propofol sedation

In South Korea, as in many other countries, propofol sedation is performed by practitioners across a broad range of specialties in our country. However, this has led to significant variation in propofol sedation practices, as shown in a series of reports by the Korean Society of Anesthesiologists (KSA). This has led the KSA to develop a set of evidence-based practical guidelines for propofol sedation by non-anesthesiologists. Here, we provide a set of recommendations for propofol sedation, with the aim of ensuring patient safety in a variety of clinical settings. The subjects of the guidelines are patients aged ≥ 18 years who were receiving diagnostic or therapeutic procedures under propofol sedation in a variety of hospital classes. The committee developed the guidelines via a de novo method, using key questions created across 10 sub-themes for data collection as well as evidence from the literature. In addition, meta-analyses were performed for three key questions. Recommendations were made based on the available evidence, and graded according to the modified Grading of Recommendations Assessment, Development and Evaluation system. Draft guidelines were scrutinized and discussed by advisory panels, and agreement was achieved via the Delphi consensus process. The guidelines contain 33 recommendations that have been endorsed by the KSA Executive Committee. These guidelines are not a legal standard of care and are not absolute requirements; rather they are recommendations that may be adopted, modified, or rejected according to clinical considerations.

Anaphylactoid reaction after injection of ketorolac in a loading dose for patient-controlled analgesia -A case report-

Anaphylaxis is a severe and life-threatening systemic hypersensitivity reaction. Ketorolac is a popular drug used for patient-controlled analgesia. Although anaphylactic reaction to ketorolac has not been frequently reported, it can develop by way of several mechanisms. A 41-year-old male patient was scheduled for laparoscopic correction of a perforated gastric ulcer. Emergency surgery was performed under general anesthesia with no complications. Near the end of anesthesia administration, ketorolac in a loading dose was administered intravenously in order to launch patient-controlled analgesia. Following injection, urticaria-like skin lesions, including rashes and wheels appeared systemically; tachycardia and breathing difficulty with oxygen desaturation also developed. Through additional inquiry into the patients drug history, past experience with ibuprofen allergy was identified. Antihistamine, steroid, and aminophylline were administered, and continuous positive airway pressure by full facial mask was applied to relieve bronchospastic symptoms. The patient recovered without further complications.

Contribution of Donor Factors to Post-Reperfusion Severe Hyperglycemia in Patients Undergoing Living Donor Liver Transplantation

BACKGROUND Blood glucose levels increase abruptly after graft reperfusion during living donor liver transplantation (LDLT), but studies on perioperative factors contributing to this phenomenon are rare. We developed a predictive model for post-reperfusion severe hyperglycemia (PRSH) based on donor-related factors. MATERIAL AND METHODS Preoperative and intraoperative recipient data, as well as donor data, on 279 LDLT cases were reviewed. The mean blood glucose levels at each LDLT surgical phase were calculated, and patients were divided into PRSH and non-PRSH groups using a cutoff of 230 mg/dL mean blood glucose level during the neo-hepatic phase. Perioperative variables were compared between the 2 groups, and selected variables were subjected to multivariate logistic regression to establish a predictive model for PRSH. RESULTS There were 128 patients (45.9%) who developed PRSH, which was associated with preoperative diabetes mellitus but not with model for end-stage liver disease or Child-Pugh-Turcotte score. Intraoperatively, the PRSH group required more blood transfusions and experienced more circulatory insufficiency than did the non-PRSH group. PRSH patients received grafts with higher-level fatty changes and greater graft-to-recipient ratios (GRWRs) (both p<0.05). The multivariate predictive model included GRWR, graft fatty change ≥10% (OR 3.53), post-reperfusion syndrome ≥5 min in duration (OR 5.68), and recipient diabetes mellitus (OR 2.92) as independent risk factors. The risk of PRSH was proportional to the rise in GRWR. CONCLUSIONS PRSH development was heavily influenced by donor-related factors. Graft size, extent of fatty change, and post-reperfusion syndrome were identified as independent donor-associated predictors of PRSH.

Serum interleukin-6 and tumor necrosis factor-α are associated with early graft regeneration after living donor liver transplantation

Background Liver graft regeneration is orchestrated by specific and sequential stimuli, including hepatocyte growth factors, cytokines, and catecholamines. We evaluated the association between preoperative serum cytokines and early liver graft regeneration in human living donor liver transplantation (LDLT). Patients and methods We retrospectively reviewed the data of adult patients who underwent LDLT from January 2010 to December 2014. Serum cytokines, including interleukin (IL)-2, 6, 10, 12, 17, interferon (IFN)-γ and tumor necrosis factor (TNF)-α were measured in the recipients 1 day before surgery and on postoperative day (POD) 7. Liver graft volume was estimated using abdominal computed tomography images of the donors and recipients. Results In total, 226 patients were analyzed in this study. Median preoperative levels of serum cytokines were as follows: IL-2, 0.1 (0.1–1.6) pg/mL; IL-6, 7.3 (0.1–30.2) pg/mL; IL-10, 0.5 (0.1–11.0) pg/mL; IL-12, 0.1 (0.1–0.1) pg/mL; IL-17, 2.0 (0.1–16.4) pg/mL; IFN-γ, 3.2 (0.1–16.0) pg/mL; and TNF-α, 9.8 (5.4–17.9) pg/mL. Higher preoperative serum levels of IL-6, IL-10, and TNF-α, dichotomized at the median, were associated with increased relative liver volumes by POD 7. Multivariate analysis revealed that higher levels of serum IL-6 and TNF-α were independently associated with increased graft volume during the first 1 week after LDLT, based on the lower levels of those cytokines. Conclusions IL-6 and TNF-α were important mediators of the success of early graft regeneration in patients who underwent LDLT.

Proposal for a New Predictive Model of Short-Term Mortality After Living Donor Liver Transplantation due to Acute Liver Failure

BACKGROUND Acute liver failure (ALF) is known to be a rapidly progressive and fatal disease. Various models which could help to estimate the post-transplant outcome for ALF have been developed; however, none of them have been proved to be the definitive predictive model of accuracy. We suggest a new predictive model, and investigated which model has the highest predictive accuracy for the short-term outcome in patients who underwent living donor liver transplantation (LDLT) due to ALF. MATERIAL AND METHODS Data from a total 88 patients were collected retrospectively. Kings College Hospital criteria (KCH), Child-Turcotte-Pugh (CTP) classification, and model for end-stage liver disease (MELD) score were calculated. Univariate analysis was performed, and then multivariate statistical adjustment for preoperative variables of ALF prognosis was performed. A new predictive model was developed, called the MELD conjugated serum phosphorus model (MELD-p). The individual diagnostic accuracy and cut-off value of models in predicting 3-month post-transplant mortality were evaluated using the area under the receiver operating characteristic curve (AUC). The difference in AUC between MELD-p and the other models was analyzed. The diagnostic improvement in MELD-p was assessed using the net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS The MELD-p and MELD scores had high predictive accuracy (AUC >0.9). KCH and serum phosphorus had an acceptable predictive ability (AUC >0.7). The CTP classification failed to show discriminative accuracy in predicting 3-month post-transplant mortality. The difference in AUC between MELD-p and the other models had statistically significant associations with CTP and KCH. The cut-off value of MELD-p was 3.98 for predicting 3-month post-transplant mortality. The NRI was 9.9% and the IDI was 2.9%. CONCLUSIONS MELD-p score can predict 3-month post-transplant mortality better than other scoring systems after LDLT due to ALF. The recommended cut-off value of MELD-p is 3.98.

Prediction of Intraoperative Circulatory Risk Based on Preoperative Neutrophil-to-Lymphocyte Ratio in Patients Undergoing Living Donor Liver Transplantation.

BACKGROUND Intraoperative circulatory risk factors are associated with unfavorable outcomes after living donor liver transplantation (LDLT). We investigated whether the preoperative neutrophil-to-lymphocyte ratio (NLR) can predict intraoperative circulatory risks. MATERIAL AND METHODS The perioperative data of 276 patients who underwent LDLT were reviewed retrospectively. The intraoperative circulatory risk score (ICRS) was calculated using the inotropic score, hypotension, blood transfusion, oliguria, and change in serum lactate during LDLT. Perioperative variables including NLRs were compared between the high (≥3.0) and low (<3.0) ICRS groups, and a predictive model for high ICRS was developed. RESULTS A high ICRS was associated with poor preoperative physical condition and unfavorable postoperative outcomes. The NLR progressively increased during the LDLT perioperative period. However, only preoperative NLRs differed significantly between the high and low ICRS groups (6.2 vs. 3.9, respectively; p<0.05). The predictive accuracy of the NLR (area under the receiver operator curve, 0.635) did not differ from those of the model for end-stage liver disease (MELD) and Child-Pugh-Turcotte scores. After multivariate adjustment, preoperative NLR ≥3.8 was identified as an independent predictor of high ICRS (risk ratio 3.15; p=0.004) together with preoperative hemodialysis and intraoperatively administered calcium chloride. CONCLUSIONS Intraoperative circulatory risks are associated with several detrimental outcomes following LDLT. The preoperative NLR is predictive of intraoperative circulatory risks.