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.

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.

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.

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.

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.

Predictors of high intraoperative blood loss derived by simple and objective method in adult living donor liver transplantation.

We conducted a risk factor analysis for high intraoperative blood loss (IBL) in 555 living donor liver transplantation (LDLT) cases with a simple and objective method of IBL estimation based on the concept of red cell mass (RCM): Lost RCM (mL) = patient's estimated blood volume (mL) × (preoperative hematocrit in % - postoperative hematocrit in %) + (transfused leukocyte-depleted red blood cell in units × 213 × 70%) + (transfused Cell Saver blood in mL × 55%). Analysis of 33 preoperative variables revealed that Model for End-stage Liver Disease (MELD) score, albumin, the presence of ascites, and previous abdominal surgery were correlated with high IBL (lost RCM > 1000 mL) in multivariate logistical regression analysis. In conclusion, we found that MELD score, albumin, the presence of ascites, and previous abdominal surgery were significantly correlated with high IBL during adult LDLT.

Comparison of the prophylactic anti-emetic efficacy of ramosetron and ondansetron in patients at high-risk for postoperative nausea and vomiting after total knee replacement.

We compared the prophylactic anti-emetic efficacy of ramosetron, a newly developed 5-HT(3) antagonist, and ondansetron in patients at high-risk for postoperative nausea and vomiting after total knee replacement. Eighty-four patients with three risk factors for postoperative nausea and vomiting (female, non-smoking and use of postoperative opioid use (ropivacaine and hydromorphone patient controlled epidural analgesia)) undergoing unilateral total knee replacement were randomly allocated to ramosetron 0.3 mg (n = 42) or ondansetron 4 mg (n = 42) groups. A complete response (no postoperative nausea and vomiting and no rescue anti-emetic) and the incidence of postoperative nausea and vomiting were assessed for 48 h after surgery at 0-2 h, 2-6 h, 6-24 h, and 24-48 h. More patients in the ramosetron group had a complete response between 2 and 48 h. The incidence of nausea between 2 and 24 h and the severity of nausea between 2 and 48 h were also less in the ramosetron group. Ramosetron was more effective than ondansetron in preventing postoperative nausea and vomiting in patients at high risk undergoing unilateral total knee replacement.

Greater hemodynamic instability with histidine-tryptophan-ketoglutarate solution than University of Wisconsin solution during the reperfusion period in living donor liver transplantation.

OBJECTIVE: University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) solutions are the 2 most commonly used liver preservation solutions. The aim of this study was to compare cardiovascular stability, acid-base status, and potassium concentrations between patients who received grafts preserved in either UW or HTK solution in orthotopic liver transplantation (OLT). PATIENTS AND METHODS: In this retrospective study, 87 patients who underwent living donor OLT were divided into 2 groups: UW (n = 28) and HTK (n = 59). Group HTK was subdivided into group NF-HTK (n = 31; nonflushed before reperfusion) and group F-HTK (n = 28; flushed before reperfusion). We determined mean arterial pressure (MAP) and heart rate every minute for 5 minutes after reperfusion and the maximum change in these values and incidence of postreperfusion syndrome (PRS). Body temperature, cardiovascular and acid-base parameters, as well as potassium concentrations were compared at 5 minutes before and 5 and 30 minutes after reperfusion. RESULTS: The maximum decreases in MAP within 5 minutes after reperfusion were significantly greater in both the NF-HTK and the F-HTK groups. The rate of PRS was significantly greater in the NF-HTK compared with the UW group. Flushing with HTK solution decreased the rate of PRS; there was no significant difference between the F-HTK and UW groups. All serial changes in body temperature, cardiovascular and acid-base parameters, as well as potassium concentrations were similar among the 3 groups. CONCLUSIONS: The incidence of PRS was greater using HTK compared with UW solution during the reperfusion period. Therefore, careful hemodynamic management is advised when using HTK solution.

Peroneal neuropathy after liver transplantation.

INTRODUCTION: The incidence of peroneal neuropathy (PN), occurring predominantly in the left leg, increases after the incorporation of intermittent pneumatic compression (IPC) devices among adult liver transplantation (OLT) recipients in our hospital. The aim of this study was to investigate the possible risk factors for PN and the reason for the left-leg predominance. METHODS: We retrospectively reviewed the medical records of 501 OLT recipients. The patients were first divided into 2 groups, PN (n = 33) and non-PN (n = 468), to assess possible risk factors. The patients were then categorized into IPC (n = 262) and non-IPC (n = 239) groups according to the use of IPC devices. In a subsequent prospective study, we measured the degree and duration of the tilt of the operating table during OLT to investigate their relationship to the predominant left-leg PN. RESULTS: The rate of IPC device use was significantly greater among the PN than non-PN group (78.8% vs 50.4%, P < .01). The incidence of PN was significantly higher among the IPC than non-IPC group (9.9% vs 2.9%, P < .01). The degree and duration of left tilt of the operating table were greater and longer than the right tilt. CONCLUSIONS: The use of IPC devices during OLT increased the occurrence of PN and the left tilt of the operating table was strongly related to the predominant left-leg PN. Careful protection of the vulnerable point and minimization of the tilting of the operating table is advised during OLT, especially when IPC devices are used.

Evaluation of the Cobra perilaryngeal airway (CPLA) as an airway conduit.

BACKGROUND AND OBJECTIVE: The effectiveness of the Cobra perilaryngeal airway as a routine airway device and as a conduit for tracheal intubation has not been prospectively studied to date. This study aimed to evaluate the Cobra perilaryngeal airway for its potential role in an emergency airway rescue, by analysing its use as a bridge to blind or fibre-optic-guided intubation. METHODS: In 49 patients, the procedure was carried out as follows: fibre-optic view through the Cobra perilaryngeal airway was assessed after the insertion of the Cobra perilaryngeal airway, then blind intubation through the Cobra perilaryngeal airway was attempted. After evaluating the success of blind intubation, fibre-optic-guided intubation was performed through the Cobra perilaryngeal airway. The endotracheal tube was removed after evaluating the success of fibre-optic-guided intubation, and then conventional laryngoscopy was carried out to evaluate the Cormack & Lehane grade and airway trauma. RESULTS: In all, 95.9% (47/49) of patients had adequate ventilation using the Cobra perilaryngeal airway; the success rates for the blind and fibre-optic-guided intubation were 36.2% and 83.0%, respectively. The patients were divided into two groups according to the fibre-optic view. Group 1 included patients with an obstructed view by an anterior grill of the Cobra perilaryngeal airway head, and a view of the anterior epiglottis (downfolded epiglottis) with or without a visible larynx (16/47, 34.0%). Group 2 included the remaining patients (31/47, 66.0%). The success rates of the blind and fibre-optic intubations were different between the two groups (blind intubation: 12.5% vs. 48.4%, fibre-optic intubation: 62.5% vs. 93.6%, P 0.05). 42.6% of patients had blood staining after removing the device and complications such as trauma and oedema were confirmed under direct laryngoscopy. CONCLUSION: This study suggests that the Cobra perilaryngeal airway could be a useful airway device as a vehicle for fibre-optic-guided intubation; however, it needs caution against airway trauma.

The effects of the exaggerated lithotomy position for radical perineal prostatectomy on respiratory mechanics.

The exaggerated lithotomy position is used during radical perineal prostatectomy to increase perineal exposure. The aim of this study was to evaluate the effects of the exaggerated lithotomy position on respiratory mechanics and arterial blood gases. In the exaggerated lithotomy position, dynamic compliance and static compliance were found to be significantly decreased by 27.4% and 34.8%, respectively, whilst peak, plateau, and mean airway pressures increased significantly by 34.0%, 45.8% and 31.7%, respectively. The physiological dead space/tidal volume ratio and total inspiratory work of breathing increased significantly by 11.1% and 33.7%, respectively. Arterial oxygen tension was significantly decreased by 26.9%; however, no significant differences were seen in end-tidal or arterial carbon dioxide tension. These results indicate that the exaggerated lithotomy position under general anaesthesia can cause significant effects on respiratory system mechanics and arterial oxygenation and highlights the need for careful monitoring of patients placed in this position for surgery.