Relationship Between Intraoperative Bispectral Index and Consciousness Recovery in Patients With Hepatic Encephalopathy Undergoing Liver Transplant: A Retrospective Analysis.

BACKGROUND: Although liver transplant (LT) improves liver function and restores symptoms of hepatic encephalopathy (HE), there is no index to predict the recovery of consciousness in patients with HE during LT. In this study, we evaluated the relationship between intraoperative bispectral index (BIS) values and the recovery of consciousness in patients with HE who were undergoing LT. METHODS: Patients with HE who underwent LT from June 2011 to December 2017 at our institution were enrolled. A total of 64 patients were enrolled, and, using the West Haven Criteria, they were divided into 2 groups: nonsevere HE group (n = 26), grades 1 to 2 HE; and severe HE group (n = 38), grades 3 to 4 HE. Grade of HE, intraoperative BIS, minimum alveolar concentration values, postoperative Glasgow Coma Scale (GCS) score, and the time to recover consciousness were compared. RESULTS: The severe HE group showed lower BIS after anesthetic induction compared with the nonsevere HE group (P = .005). In the severe HE group, intraoperative BIS gradient (the difference between values measured 4 hours after reperfusion and immediately after anesthesia induction) was significantly larger than in the nonsevere HE group (P = .001). Time to recovery of consciousness was prolonged in the severe HE group (P = .002). Model for End-Stage Liver Disease (MELD) score and the GCS score at 24 hours after LT were associated with delayed recovery of consciousness (MELD score: hazard ratio, 1.103; 95% CI, 1.002-1.214; P = .046; GCS score at 24 hours after LT: hazard ratio, 0.688; 95% CI, 0.566-0.835; P < .001). CONCLUSIONS: Our study indicated that BIS values immediately after anesthesia induction were significantly lower in patients with severe HE. However, it did not show a significant relationship with the time to recovery of consciousness after LT. Multivariate analysis demonstrated that MELD score and GCS score at 24 hours after LT were associated with the time to recovery of consciousness.

Association of Platelet Count and Platelet Transfusion With Serotonin Level During Living Donor Liver Transplantation: Possible Connection to Graft Regeneration.

BACKGROUND: We recently showed that platelet counts and the amount of platelet transfusion during liver transplantation are positively associated with early graft regeneration. It was hypothesized that platelet-derived serotonin mediates liver regeneration. OBJECTIVES: This study aimed to evaluate the association between intraoperative platelet count, platelet transfusion, and serum serotonin level. METHODS: Thirty-two recipients undergoing living-donor liver transplantation were enrolled into this prospective observational study. Serum platelet counts and serotonin levels were measured at the following times: anesthetic induction, start of the anhepatic phase, before graft reperfusion, 5 minutes/1 hour/3 hours/5 hours after graft reperfusion, and before/after platelet transfusion. Serotonin was measured by using a liquid chromatography tandem mass spectrometry. RESULTS: Serotonin level at the anesthetic induction was 24.5 µg/mL (interquartile range, 14.6 to 38.1 µg/mL). During surgery, serial changes in platelet counts and serotonin levels showed a similar trend: they decreased during the anhepatic phase, increased during the first hour after graft reperfusion, and thereafter gradually decreased. Serotonin level was positively correlated with platelet counts (correlation coefficient = 0.620, P < .001). Allogeneic platelet transfusion significantly increased platelet count from 22 (19-31) × 109/L to 53 (50-81) × 109/L (P = .008) and it also increased serum serotonin from 11.04 (6.41-15.34) µg/mL to 34.26 (25.86-41.94) µg/mL (P = .008). CONCLUSIONS: Our findings indicate that allogeneic platelets could act as effector cells deriving serotonins. Also, our findings support the hypothesis that the association between platelets and post-transplantation graft regeneration is mediated by serotonin. Further studies are warranted regarding the respective role of serotonin and other platelet-derived molecules mediating liver regeneration.

Ischemic Preconditioning Produces Comparable Protection Against Hepatic Ischemia/Reperfusion Injury Under Isoflurane and Sevoflurane Anesthesia in Rats.

BACKGROUND: Various volatile anesthetics and ischemic preconditioning (IP) have been demonstrated to exert protective effect against ischemia/reperfusion (I/R) injury in liver. We aimed to determine whether application of IP under isoflurane and sevoflurane anesthesia would confer protection against hepatic I/R injury in rats. METHODS: Thirty-eight rats weighing 270 to 300 grams were randomly divided into 2 groups: isoflurane (1.5%) and sevoflurane (2.5%) anesthesia groups. Each group was subdivided into sham (n = 3), non-IP (n = 8; 45 minutes of hepatic ischemia), and IP (n = 8, IP consisting of 10-minute ischemia plus 15-minute reperfusion before prolonged ischemia) groups. The degree of hepatic injury and expressions of B-cell lymphoma 2 (Bcl-2) and caspase 3 were compared at 2 hours after reperfusion. RESULTS: Hepatic ischemia induced significant degree of I/R injuries in both isoflurane and sevoflurane non-IP groups. In both anesthetic groups, introduction of IP dramatically attenuated I/R injuries as marked by significantly lower aspartate aminotransferase and aminotransferase levels and better histologic grades compared with corresponding non-IP groups. There were 2.3- and 1.7-fold increases in Bcl-2 mRNA levels in isoflurane and sevoflurane IP groups, respectively, compared with corresponding non-IP groups (both P < .05). Caspase 3 level was significantly high in the isoflurane non-IP group compared with the sham group; however, there were no differences among the sevoflurane groups. CONCLUSIONS: The degree of hepatic I/R injury was significantly high in both isoflurane and sevoflurane groups in rats. However, application of IP significantly protected against I/R injury in both volatile anesthetic groups to similar degrees, and upregulation of Bcl-2 might be an important mechanism.

Effect of Prereperfusion Ephedrine on Postreperfusion Syndrome and Graft Function in Living Donor Liver Transplantation.

A characteristic pattern of hemodynamic changes that may occur after reperfusion during liver transplantation (LT) is known as postreperfusion syndrome (PRS). We investigated the effect of prophylactic ephedrine administration on PRS and postoperative laboratory results in living donor LT. The medical records of adult recipients who underwent living donor LT were reviewed. A total of 308 recipients were divided into the prophylaxis group and the nonprophylaxis group. Graft factors, preoperative and intraoperative recipient factors, and postoperative laboratory results were compared between the 2 groups. Graft factors and preoperative and intraoperative recipient factors did not differ between the 2 groups, except the prevalence of diabetes mellitus and etiology of liver disease. After reperfusion, PRS occurred more frequently (43.2% vs 25.0%; P = .006), and mean arterial pressure was more reduced compared with prereperfusion values (33.7 ± 15.8% vs 22.3 ± 23.5%; P < .001) in the nonprophylaxis group than the prophylaxis group. Postoperative laboratory results did not differ between the 2 groups. In conclusion, prereperfusion administration of ephedrine reduced the incidence and severity of PRS. Further prospective studies on the relationship between prophylactic medication and posttransplantation outcomes are needed.

Use of Dexmedetomidine in Liver Transplant Recipients With Postoperative Agitated Delirium.

BACKGROUND AND OBJECTIVE: Agitated delirium has frequently occurred after liver transplantation in the intensive care unit (ICU) and sedative agents are used to treat patients. Recently, dexmedetomidine has been considered to be a promising agent for agitated delirium. METHODS: This study took place between January 2010 and October 2012 and 42 recipients were retrospectively enrolled. Sixteen recipients were enrolled in the dexmedetomidine group and 26 recipients were placed in the haloperidol group. To compare dexmedetomidine and haloperidol, the total ICU length of stay (ICU LOS), the ICU LOS after drug administration, and the supplemental doses of sedative agents used were assessed. The endpoint was discharge from the ICU. RESULTS: There were no significant drug-related complications in either group. Dexmedetomidine significantly decreased the ICU LOS and ICU LOS after the occurrence of delirium compared to haloperidol (13.7 days vs. 8.3 days, P = .039, 10.1 days vs. 3.1 days, P = .009). In the dexmedetomidine group, the dose of supplemental midazolam needed was lower than in the haloperidol group (1.5 mg vs. 6.85 mg, P < .001). CONCLUSION: Dexmedetomidine is a promising agent for the treatment of ICU-associated agitated delirium in liver transplantation recipients.

Evaluation of "flat-line" thromboelastography after reperfusion during liver transplantation.

BACKGROUND: "Flat-line" (no clot formation) thromboelastography (TEG) is frequently observed after graft reperfusion during liver transplantation (LT). We aimed to evaluate the incidence and causes of flat-line TEG after graft reperfusion during LT. METHODS: With institutional review board approval, data of 208 consecutive recipients who underwent LT from May 2010 to May 2012 were retrospectively reviewed. We performed 3 different types of TEG measurements at 5 minutes after graft reperfusion: native TEG (nTEG), tranexamic acid-added TEG (tTEG), and protamine-added TEG (pTEG). The flat-line TEG was defined as having no trace at all at 60 minutes of TEG. We examined the incidence and causes of flat-line nTEG. We also compared recipients with flat-line nTEG (F group) and clot-forming nTEG (C group). RESULTS: One hundred eighty-two recipients were included in the final analysis. The incidence of flat-line nTEG was 27% (49/182 cases). Among 49 recipients in the F group, 28 recipients showed clot formation in both tTEG and pTEG, 19 recipients in only tTEG, and 1 recipient in only pTEG; 1 recipient showed no clot formation in any TEGs. Graft from the deceased donor was more frequently observed in the F group than in the C group (P = .039). The F group showed decreased platelet count (P = .001), increased prothrombin time (P = .002), and decreased fibrinogen (P = .009) compared with the C group. CONCLUSIONS: No clot formation was relatively common after reperfusion during LT, and the main causes were hyperfibrinolysis and heparin effect. Liver graft from deceased donors was associated more frequently with no clot formation after reperfusion during LT.

The comparisons of hepatitis C virus RNA level between intraoperative blood salvage (cell saver) and systemic hepatitis C virus RNA kinetics during liver transplantation.

BACKGROUND: Cell Saver (CS; Haemonemic Corp, Braintree, Mass, United States) is frequently used to decrease transfusion requirements of homologous blood during liver transplantation (OLT). However, the use of CS in hepatitis C virus (HCV)-infected recipients is still debated owing to the potential elevation of HCV RNA level. In this study, we compared HCV RNA levels of CS blood with a series of blood samples obtained from HCV-infected OLT recipients. METHODS: Twelve HCV-infected patients with >50,000 copies/mL of HCV RNA were enrolled. HCV RNA was measured immediately after induction (I), at the end of anhepatic period (II), at the end of operation (III), and from the first returned blood in CS (CSb). HCV RNA level at each time period was compared. RESULTS: HCV RNA levels ranged from 77,931 to 9,072,000 copies/mL at I. When compared to I, HCV RNA levels were reduced to 11.1% ± 13.0% and 0.7% ± 1.0% at II and III, respectively. Also, the RNA level reduced to 3.0% ± 2.0% of I after CS processing. The HCV RNA level at I was significantly higher than the levels at II, III, and CSb (P = .012, each), and the level at II was significantly higher than the level at III (P = .012). The HCV RNA level at CSb showed no statistical difference with the levels at II, but it was significantly higher than the level at III (P = .042). CONCLUSIONS: The use of CS in HCV-infected OLT recipients seems to carry no additional risk with respect to intraoperative HCV RNA kinetics.

Risk factors for inadvertent hypothermia during adult living-donor liver transplantation.

BACKGROUND: Hypothermia (core temperature <35°C) causes multiple physiologic disturbances, including coagulopathy and cardiac dysfunction. Patients undergoing liver transplantation are at risk of inadvertent hypothermia and might be more vulnerable to its adverse effects. We sought to identify the factors contributing to hypothermia during living-donor liver transplantation (LDLT), which have not yet been studied in depth. METHODS: Medical records of 134 recipients who underwent adult-to-adult LDLT were reviewed. Core temperature at the following time points were taken: anesthetic induction, skin incision, start and end of the anhepatic phase, and hourly after hepatic reperfusion. RESULTS: Of 134 recipients, 29 (21.6%) developed hypothermia during surgery. Four independent risk factors for hypothermia were identified: small body weight-to-body surface area ratio, acute hepatic failure, high Model for End-Stage Liver Disease (MELD) score, and low graft-to-recipient weight ratio. The amount of core temperature drop was positively correlated with the number of involved risk factors. Each risk factor had a respective contribution according to the operative phases: body weight-to-body surface area ratio and the MELD score for the preanhepatic phase, acute deterioration of hepatic failure for the anhepatic phase, and graft-to-recipient weight ratio was for the postreperfusion phase. CONCLUSIONS: Hypothermia was independently associated with the recipient's morphometric characteristics, emergency of end-stage liver disease, MELD score, and graft volume. These factors showed a cumulative effect, and the role of each factor was different according to the operative phase. These results should aid in the development of an optimal thermal strategy during LDLT.

Analysis of predictors for lactate elimination after reperfusion in recipients of living-donor liver transplantation.

BACKGROUND: Graft-recipient weight ratio (GRWR) is the only documented predictor that influences the lactate elimination after reperfusion in living-donor liver transplantation (LDLT). This study was performed to investigate the predictors of lactate elimination after reperfusion in recipients of adult LDLT. METHODS: The medical records of 159 patients who underwent LDLT were analyzed. Lactate level (mmol/L) was measured from just before the initiation of surgery (P0) and 5, 60, and 120 minutes after reperfusion of graft (R0, R1, and R2, respectively). The change of lactate level after reperfusion was defined as difference between lactate level measured at R0 and R2. Patients were divided into accumulation and elimination groups. Donor and recipient factors were compared between the 2 groups. RESULTS: Lactate accumulation occurred in 80 of 159 recipients (50.3%), and elimination occurred in 79 (49.7%). GRWR and Model for End-Stage Liver Disease (MELD) score were higher in the elimination group. Lactate at R0 was lower in the elimination group. CONCLUSIONS: Higher GRWR and MELD score and lower lactate level immediate after reperfusion of graft were predictors of lactate elimination after reperfusion during adult LDLT.

Factors associated with consciousness recovery time after liver transplantation in recipients with hepatic encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) occurs as a result of liver failure and is often considered to be a clinical indication for liver transplantation (LT). An assessment of post-transplantation consciousness level in recipients with HE is crucial, because recovery of consciousness implies reestablishment of transplant liver function and lack of perioperative brain damage. The purpose of this study is to evaluate factors associated with consciousness recovery time after LT in recipients with HE. METHODS: Out of 633 adult recipients who underwent LT, recipients who exhibited HE at the time of LT were analyzed retrospectively. The time between graft reperfusion and postoperative consciousness recovery was determined, and recipients were divided into 2 groups: group E with recovery of consciousness early (≤48 hours), and group L with recovery of consciousness late (>48 hours). Analyzed variables included recipient sex, age, graft type, Model for End-Stage Liver Disease score, HE history/duration/type/grade, and preoperative laboratory values, including blood ammonia concentration. RESULTS: HE was present at the time of LT in 69 (10.9%) of 633 recipients. Among the 69 recipients, 11 recipients who died or underwent reoperation before consciousness recovery were excluded, and 58 recipients (group E: n = 32; group L: n = 26) were enrolled into analysis. Multivariate analysis showed that HE duration >5 days (odds ratio [OR], 15.58; 95% confidence interval [CI], 1.35-179.56; P = .028) and HE type C (OR, 30.90; 95% CI, 1.67-573.48; P = .021) were the independent factors associated with late recovery from HE after LT. CONCLUSIONS: We suggest that recipients with long-duration or type C HE should be carefully managed during the post-transplantation period to prevent deterioration of HE.

The protective effect of ischemic preconditioning against hepatic ischemic-reperfusion injury under isoflurane anesthesia in rats.

PURPOSE: Apoptosis is a central mechanism of ischemic-reperfusion injury (IRI) to the liver. Among the methods to reduce IRI, ischemic preconditioning (IP) has been shown to confer protection. Therefore, the aim of this study was to determine if IP conferred protection against hepatic IRI under isoflurane anesthesia in rats and to investigate underlying protective mechanisms. MATERIALS AND METHODS: Twenty-three rats weighing 270 to 300 grams were randomly divided into three groups: (1) the sham operated group (n = 5); (2) the non-IP group (n = 9; 45 minutes of hepatic ischemia followed by 2 hours of reperfusion); and (3) the IP group (n = 9); IP induced by 10 minutes of hepatic ischemia followed by 15 minutes of reperfusion before 45 minutes of prolonged hepatic ischemia). Anesthesia was maintained with isoflurane (1.5%). We compared the degrees of hepatic injury and expressions of B cell lymphoma 2 (Bcl-2) and caspase 3 and 8 mRNAs. RESULTS: The IP group showed significantly lower levels of aspartate transaminase and alanine transaminase as well as reduced histological grades of hepatocyte injury compared with the non-IP group at 2 hours after reperfusion. At the corresponding time, the Bcl-2 mRNA level was 2-fold higher in the IP group. Caspase 3 mRNA levels were highest in the non-IP group significantly compared with the sham cohort. Similarly, caspase 8 mRNA levels were highest in the Non_IP group albeit not significancely. CONCLUSION: IP protected against hepatic IRI under isoflurane anesthesia in rats. The mechanism of protection appeared to involve upregulation of Bcl-2 expression resulting in inhibited apoptosis.

Comparison of mixed venous oxygen saturation after in vitro calibration of pulmonary artery catheter with that of pulmonary arterial blood in patients undergoing living donor liver transplantation.

INTRODUCTION: Mixed venous saturation (SvO2) reflects the balance between oxygen delivery and consumption throughout the body. A multifunction pulmonary artery catheter (PAC) can monitor continuous SvO2 after in vitro calibration (CSvO2), obviating the need for in vivo calibration with pulmonary arterial blood. In critically ill patients CSvO2 has shown a good correlation with measured SvO2 of pulmonary arterial blood using co-oximetry (MSvO2). The aim of this study was to compare CSvO2 and MSvO2 in liver transplantation (OLT) recipients. METHODS: We enrolled 44 OLT recipients for comparison with 24 coronary artery bypass graft (CABG) controls free of end-stage liver disease. After anesthetic induction, the PAC was inserted after in vitro calibration and CSvO2 and MSvO2 simultaneously measured. In OLT recipients, additional measurements of CSvO2 and MSvO2 were performed at anhepatic and postreperfusion phases. Pearson's correlation analysis was used to evaluate the correlation between the 2 measurements. A Bland-Altman analysis was used to determine precision of and bias between the 2 measurements. With ±3% regarded to be interchangeable. RESULTS: Cardiac output and intrapulmonary shunt in CABG patients were lower than among OLT recipients. OLT recipients, showed a significant correlation between CSvO2 and MSvO2, but the coefficients were different during the three phases of OLT (r = 0.597, 0.753, and 0.756). In addition, bias values between the two measurements were 6.0%, 6.4%, and 2.9% for the preanhepatic, anhepatic, and postreperfusion phases, respectively, with 29.5%, 31.8%, and 50% of them being interchangeable. In contrast CABG patients showed bias in -0.17% with 75% of measurements interchangeable. CONCLUSION: While in vitro calibration of the PAC can be used in CABG patients, MSvO2 is higher than CSvO2 in OLT recipients. Therefore, in vivo calibration with pulmonary arterial blood is necessary for accurate monitoring of SvO2 in OLT recipients.

Vecuronium requirements according to the operative phase during living donor liver transplantation under desflurane anesthesia.

INTRODUCTION: The requirements of nondepolarizing neuromuscular blocking agent during liver transplantation show conflicting results. We sought to evaluate the requirements according to the operative phase and find extrahepatic factors that influence neuromuscular blocking agent requirements. METHODS: We enrolled 35 patients undergoing living donor liver transplantation. Continuous infusion of vecuronium was adjusted every 15 minutes for consistent neuromuscular blockade aimed at T1/Tc of 0.10 monitored with a neuromuscular transmission module. We compared the mean infusion dose in each phase, and investigated whether it is correlated with preoperative Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, graft-recipient weight ratio (GRWR), or time to recovery of first twitch response to train-of-four (TOF) stimulation. RESULTS: There was a significant difference between vecuronium doses during each phase (P < .001): 0.48 ± 0.16 µg/kg/min, preanhepatic; 0.38 ± 0.14 µg/kg/min, anhepatic and 0.26 ± 0.07 µg/kg/min, neohepatic phase. There was a significant positive correlation between vecuronium infusion dose in the preanhepatic phase and CTP scores (P = .006, correlation coefficient = 0.465). There was also a significant negative correlation between the time to recovery of first twitch response of TOF stimulation and vecuronium infusion dose in the preanhepatic phase (P = .001, correlation coefficient = -0.546). The infusion dose during the preanhepatic phase was not associated with the MELD score, and that of neohapatic phase not with GRWR. CONCLUSIONS: The vecuronium infusion dose requirement during the anhepatic decreased compared with that in the preanhepatic phase. It further decreased during the neohepatic phase compared with the previous phases. Vecuronium infusion dose reduction is suggested especially during the neohepatic phase for early extubation. The dose during the preanhepatic phase is suggested to be determined considering the CTP score and the time to recovery of the TOF response.

The comparison of femoral and radial arterial blood pressures during pediatric liver transplantation.

BACKGROUND: Orthotopic liver transplantation (OLT) is frequently associated with dramatic hemodynamic changes; thus, it is critical to accurately monitor blood pressure. Although comparisons between femoral arterial blood pressure (FABP) and radial arterial blood pressure (RABP) have been reported in adult liver recipients, we compared FABP with RABP in pediatric recipients. METHODS: Thirty-five pediatric liver recipients younger than 13 years of age were included in this prospective, observational study. We measured simultaneous FABP and RABP in the femoral and radial arteries at nine time points during the procedure, including: baseline (after anesthetic induction); 1 hour thereafter; 30 minutes after the beginning of the anhepatic period as well as 0, 1, 3, 5, 15, and 60 minutes after graft reperfusion. RESULTS: Of the 35 pediatric liver recipients, 2 infants and 1 13-month-old child were excluded from the analysis because of radial arterial catheter malfunction. The remaining 32 patients including 16 infants and 16 children all showed significantly higher systolic and mean FABP than RABP during most stages of pediatric OLT. Overall diastolic FABP measurements were similar to diastolic RABP throughout the study. CONCLUSIONS: Systolic and mean FABP were significantly higher than RABP during most stages of pediatric OLT. Radial arterial catheter malfunctions were not uncommon during pediatric OLT. Our results indicated that it is useful to cannulate the femoral artery to accurately and reliably measure arterial blood pressure to detect hemodynamic instability during pediatric OLT.

Arthroscopic shoulder surgery under general anesthesia with brachial plexus block: postoperative respiratory dysfunction of combined obstructive and restrictive pathology.

OBJECTIVE: Changes in respiratory parameters and pulmonary function tests were evaluated after shoulder arthroscopic surgery with brachial plexus block (BPB). The purpose of this study was to identify the mechanism of respiratory dysfunction after this type of surgery. METHODS: Patients undergoing arthroscopic rotator cuff repair under general anesthesia (GA) with BPB were enrolled in the arthroscopy group (n = 30) while those undergoing open reduction of a clavicle or humerus fracture under GA were enrolled in the control group (n = 30). Forced vital capacity (FVC) and forced expiratory volume 1 s (FEV(1)) were measured at the outpatient clinic stage (#1) before (#2) and 20 min after BPB (#3) and 1 h after extubation (#4). Respiratory variable measurements along with the cuff leak test were performed 5 min after surgical positioning (T1) and at the start of skin closure (T2). Respiratory discomfort was evaluated after extubation. The upper airway diameters and soft tissue depth of chest wall were also measured by ultrasonography at stages #3 and #4. RESULTS: Static compliance decreased significantly at T2 in the arthroscopy group (50 ± 11 at T1 vs. 44 ± 9 ml/cm H(2)O at T2, p =0.035) but not in the control group. The incidence of positive cuff leak tests at T2 was significantly higher in the arthroscopy group than in the control group (47% in the arthroscopy group vs. 17% in controls, p =0.010). While FEV(1) and FVC remained stable at stages #1 and #2, FVC and FEV(1) decreased at stages #3 and #4 only in the arthroscopy group (FVC in arthroscopy group, #2: 3.26 ± 0.77 l; #3: 2.55 ± 0.63 l, p =0.015 vs. #2; #4: 2.66 ± 0.41 l, p =0.040 vs. #2). The subglottic diameter decreased at #4 in the arthroscopy group, while no changes occurred in the control group (0.70 ± 0.21 cm vs. 0.85 ± 0.23 cm in the arthroscopy and control groups, respectively, p =0.011). Depth of skin to pleura increased at both intercostal spaces 1-2 and 3-4 in the arthroscopy group. There were three cases of hypoxia (S(p)O(2) < 95%) with room air in the arthroscopy group while none occurred in the controls. CONCLUSION: Shoulder arthroscopic surgery under GA with BPB induced both restrictive and obstructive pathologies. It is important to maintain a high level of awareness for the potential negative respiratory effects of this surgery especially for subjects with pre-existing cardiopulmonary disease. The measurements in this study would be useful to monitor the risk of respiratory dysfunction in these patients.

Effect of active airway warming on body core temperature during adult liver transplantation.

INTRODUCTION: Active inspired gas humidification (AH) preserves body heat and maintains normothermia intraoperatively. However, it is unclear whether AH shows comparable influences during liver transplantation (OLT), which may be affected by both large internal heat loss and external heat supply. Thus, the aim of this study was to evaluate the effect of AH compared with passive humidification (PH) on body temperature in OLT. MATERIALS AND METHODS: Thirty-four adult patients undergoing living donor OLT were randomly enrolled into two groups: those given AH using a heated humidifier (HH group, n = 17) and those using a heat-and-moisture exchanger (HME group, n = 17). Both core and skin temperatures (Tc and Ts), as well as respiratory parameters, including static/dynamic lung compliances and PaO(2), were recorded at predetermined times. RESULTS: Both Tc and Ts were consistently higher among the HH versus the HME group after 2 hours of anesthesia. Differences in Tc and Ts between the two groups increased gradually over time. The overall Tc during surgery was higher among the HH than the HME group (P = .023). The incidences of hypothermia were lower in the HH group at 3 hours of anesthesia, 1 and 3 hours of reperfusion, and at the end of surgery (P = .037, 0.024, 0.005, and 0.010 respectively). The duration of hypothermia was lower in the HH than the HME group (3.9 ± 3.5 hours versus 6.7 ± 3.3 hours, P = .025). Both groups showed no significant intraoperative changes in respiratory parameters; there were no postoperative respiratory complications. CONCLUSION: Active humidification warms the patient's body effectively, lessening the incidence and duration of hypothermia during OLT with no respiratory risks.

Combined carbamazepine and pregabalin therapy in a rat model of neuropathic pain.

BACKGROUND: Carbamazepine and pregabalin have proven effects against neuropathic pain. Carbamazepine blocks voltage-dependent Na(+) channels, whereas pregabalin blocks voltage-dependent Ca(2+) channels. The authors hypothesized that the co-administration of these drugs would synergistically reduce neuropathic pain. METHODS: Neuropathic pain was induced by L5 nerve ligation in Sprague-Dawley rats. To determine their ED(50) values, carbamazepine and pregabalin were orally administered at 0.3, 3, 10, or 30 mg kg(-1). The drugs were then co-administered at 0, 1/4×ED(50), 1/2×ED(50), 1.5×ED(50), and 2×ED(50) to determine the ED(50) and ED(75) values of the drugs in combination. Allodynia was determined using the von Frey hair test and dose-effect curves and isobolograms were used to investigate drug interactions. Levels of the acute reactive protein c-Fos in the dorsal horn were evaluated as an indicator of pathological nerve excitation. RESULTS: At ED(50) levels, carbamazepine and pregabalin did not exhibit synergism, but doses higher than ED(75) were found to be synergistic. The combination index was 0.18 (strong synergy) and dose reductions were 35.7-fold for carbamazepine and 6.8-fold for pregabalin when co-administered when compared with a single administration at ED(75). The percentage allodynia relief was only 60% for carbamazepine and 80% for pregabalin by single administration, whereas their co-administration relieved allodynia by 100%. Furthermore, treatment decreased c-Fos expression in the dorsal horn, but expressional differences between animals treated with carbamazepine plus pregabalin were not significantly different from those treated with single drug. CONCLUSIONS: Carbamazepine and pregabalin ameliorate neuropathic pain synergistically at higher doses.

The effect of body mass index on spinal anaesthesia for total knee replacement arthroplasty: a dose-response study.

The aim of this study was to compare the duration of spinal anaesthesia in obese and non-obese subjects. We also quantified the effect of body mass index (BMI) on spinal anaesthesia by comparing the median effective dose (ED50) of intrathecal hyperbaric bupivacaine required in the two cohorts. One hundred and eight patients undergoing elective total knee replacement arthroplasty under combined spinal-epidural anaesthesia were enrolled as a non-obese group (BMI <27.5 kg/m(2)) or obese (O) group (BMI ≥ 27.5 kg/m(2)). Each group was further subdivided by bupivacaine doses of 6, 7, 8, 9, 10 or 11 mg, respectively. Anaesthesia was deemed successful if a bilateral T12 sensory block occurred within 15 minutes of intrathecal drug administration and epidural supplementation was not required. The ED50 for successful anaesthesia and that for successful block of tourniquet pain were determined separately by probit regression analysis. Although the analgesic duration was prolonged with higher doses of bupivacaine in group O, the ED50 for successful anaesthesia did not differ between groups. However, the incidence of tourniquet pain was lower in group O and the ED50 for block of tourniquet pain was less in group O. This study suggests that bupivacaine dose reduction is not necessary, but analgesic duration may be prolonged in patients with higher BMI. These patients require careful consideration of spinal anaesthetic dose to minimise the risk of unnecessary prolongation of anaesthesia.

The effects of intermittent inflow occlusion and hepatic steatosis on postoperative liver functions in living liver donors undergoing right hepatectomy.

BACKGROUND: Intermittent inflow occlusion (IIO) is a safe, effective method to reduce blood loss during liver resection and preserve function even among patients with underlying diseases such as steatosis and cirrhosis. Therefore, we evaluated the impact of IIO on postoperative liver function tests (LFT) and on morbidity among living liver donors undergoing a right hepatectomy, including donors with mild degrees (5%-30%) of macrovesicular steatosis (MaS). METHODS: We retrospectively reviewed the medical records of 186 living liver donors from August 2008 to September 2010. Donors were divided into two groups according to group IIO (n=81) versus Controls (no IIO, n=105). Within each group, donors were subdivided to evaluate Peak values of LFTs and complications into according the degree of MaS: group I_5 (n=36); IIO+<5% MaS, group I_30 (n=45); IIO+5%-30% MaS, group C_5 (n=55); Control+<5% MaS, and group C_30 (n=50); Control+5%-30% MaS. RESULTS: Peak aspartate aminotransferase (AST) and alanine aminotransferase (ALT) among IIO were significantly higher than Non-IIO. These values in groups I_5 and I_30 were significantly higher than groups C_5 and C_30, respectively (all, P<.01). The overall postoperative complications were comparable between groups IIO and Non-IIO, but significantly higher among group I_30 than groups I_5 (P=0.024) and C_30 (P=.012). CONCLUSIONS: Application of IIO in donors with mild macrosteatosis undergoing right hepatectomy showed significantly higher postoperative peak liver functions tests and number of overall complications than those without IIO.

Which score system can best predict recipient outcomes after living donor liver transplantation?

INTRODUCTION: Many scoring systems have been suggested to predict the outcomes of deceased donor liver transplantations. The aims of this study were to compare the Model for End-Stage Liver Disease (MELD) score with respect to other scores among patients who underwent living donor liver transplantation (LDLT) seeking to evaluate the best system to correlate with postoperative outcomes after LDLT. METHODS: We analyzed retrospectively data from 202 adult patients who underwent LDLT from January 2008 to July 2010. We calculated preoperative MELD, MELD-sodium, MELD to serum sodium ratio (MESO), integrated MELD, United Kingdom MELD, Child-Turcotte-Pugh, Acute Physiology and Chronic Health evaluation II (APACHE II), and Sequential Organ Failure Assessment (SOFA) scores in all patients. We analyzed the correlation of each score with postoperative laboratory results, as well as survival at 1, 3, 6 and 12 months after LDLT. RESULTS: There was significant positive correlation between all scores and peak total bilirubin during the first 7 days after LDLT. The MELD score showed the greatest correlation with peak total bilirubin (r=0.745). APACHE II and SOFA scores at 6 months and 1 year after LDLT and MESO score at 1 year after LDLT showed acceptable discrimination performance {area under the receiver operating characteristic curves (AUC)>0.7, while other scoring systems showed poor discrimination. However, the AUCs of each score were not significantly different from the MELD score AUC. CONCLUSION: The MELD score most correlated with total bilirubin after LDLT, while the APACHE II and SOFA scores seemed to correlate with mortality after LDLT.