Ventricular arrhythmia in patients with prolonged QT interval during liver transplantation: two cases report.

QT interval prolongation is associated with an increased risk of ventricular arrhythmia in various conditions. Cardiac electrophysiologic abnormalities including QT interval prolongation are well documented in patients with advanced liver cirrhosis. We report two cases of patients with QT interval prolongation on preoperative electrocardiography who exhibited repetitive ventricular arrhythmias with significant hemodynamic deterioration during liver transplantation. For the treatment and prevention of ventricular arrhythmias during the intraoperative period, we performed intravenous administration of lidocaine and isoproterenol, corrected imbalances of electrolytes including potassium and magnesium, and prepared a defibrillator. These cases emphasize that preoperative recognition of QT interval prolongation and adequate management to prevent fatal arrhythmias are important in patients undergoing liver transplantation.

Low-dose remifentanil to modify hemodynamic responses to tracheal intubation: comparison in normotensive and untreated/treated hypertensive Korean patients.

BACKGROUND: Remifentanil has been shown to be effective at treating potentially adverse hemodynamic responses to tracheal intubation even at low doses (< 1 µg/kg/min), which needs to be evaluated in patients with diverse cardiovascular conditions. METHODS: A low-dose regimen of remifentanil (continuous infusion of 0.1 µg/kg/min, preceded by 0.5 µg/kg bolus) was given before induction with bolus propofol and rocuronium, and heart rate as well as systolic, diastolic, and mean arterial pressures were measured at 1 min intervals from before induction to 5 min after tracheal intubation in normotensive patients, untreated hypertensive patients, and patients with known hypertension. RESULTS: The low-dose regimen of remifentanil resulted in parallel hemodynamic responses in all three groups, and was effective at limiting hemodynamic responses to tracheal intubation without excessive cardiovascular depression. Hemodynamic responses in our study showed a similar pattern to that reported in previous investigations, except for elevations in heart rate and arterial pressures over the baseline values immediately after intubation. CONCLUSIONS: We suggest that the low-dose regimen of remifentanil in our study could be routinely used to modify hemodynamic responses to tracheal intubation in patients with diverse hemodynamic characteristics. However, the development of supplementary regimens is still needed to control the brief, but exaggerated responses to tracheal intubation, especially in untreated hypertensive patients.

Vecuronium requirement during liver transplantation under sevoflurane anesthesia.

PURPOSE: In liver transplantation patients under intravenous anesthesia, the vecuronium dose is known to be reduced, especially during the anhepatic phase. Volatile anesthetics potentiate a muscle relaxation effect of neuromuscular blocking agents, so the vecuronium dose is supposed to further decrease if sevoflurane is used during liver transplantation. The purpose of this study was to determine the appropriate dose of vecuronium at each phase of liver transplantation under sevoflurane anesthesia. METHODS: Thirty-five patients scheduled for living donor liver transplantation because of liver cirrhosis were enrolled in this study. They were anesthetized with 1 MAC of sevoflurane and intermittent administration of fentanyl. Continuous infusion of vecuronium (0.5 mg/ml) was used for muscle relaxation, which was adjusted every 15 min for consistent muscle relaxation aimed at T1/Tc of 0.1 monitored by ulnar nerve stimulation. Vecuronium infusion was stopped after hepatic artery anastomosis was finished. The infusion rate of each operative phase-dissection, anhepatic, and neohepatic-was calculated and analyzed by one-way analysis of variance. The recovery time from train-of-four (TOF) count 1 to TOF ratio 25% was also measured. RESULTS: The vecuronium infusion rate of each operation phase for adequate muscle relaxation was as follows: 0.033 ± 0.009 mg/kg/h during dissection phase, 0.031 ± 0.009 mg/kg/h during anhepatic phase, and 0.026 ± 0.006 mg/kg/h during early neohepatic phase. There was a statistically significant difference between doses at each phase (P = 0.033). The recovery time from TOF count 1 to TOF ratio 25% was 103 ± 29 min. CONCLUSIONS: The required vecuronium dose in all phases was less than the known dose in the anhepatic phase (0.036 mg/kg/h) under midazolam-fentanyl anesthesia. In addition, the vecuronium infusion dose was not reduced in the anhepatic phase compared to the dissection phases.

The displacement of the tracheal tube during robot-assisted radical prostatectomy.

BACKGROUND AND OBJECTIVE: Robot-assisted prostatectomy requires pneumoperitoneum in a steep Trendelenburg position, which may induce endobronchial intubation or accidental extubation. The aim of the study was to evaluate the effect of pneumoperitoneum in 30 degrees Trendelenburg position on the displacement of the tracheal tube and to measure the changes in trachea length using fiberoptic bronchoscope. METHODS: Thirty male patients scheduled for robot-assisted radical prostatectomy were enrolled. After induction of general anaesthesia, the distance between the vocal cords and the tracheal tube tip (DeltaVE), between the tracheal tube tip and the carina (DeltaEC) and between the vocal cords and the carina (DeltaVC) was measured using a fiberoptic bronchoscope before and 10 min after pneumoperitoneum in neutral position (T1 and T2, respectively), and 2 h after pneumoperitoneum in 30 degrees Trendelenburg position (T3). RESULTS: The DeltaVC and DeltaEC decreased significantly 10 min after pneumoperitoneum in neutral position (T2) and 2 h after pneumoperitoneum in Trendelenburg position (T3) compared with those before pneumoperitoneum in neutral position (T1) (all P < 0.001). The changes in DeltaVE were not statistically significant. CONCLUSION: The confirmation of the tracheal tube position is recommended after pneumoperitoneum in steep Trendelenburg position during robot-assisted prostatectomy because the displacement of the tracheal tube may result in endobronchial intubation due to shortening of the carina-to-tube tip distance.

Assessment of cerebral oxygen supply-demand balance by near-infrared spectroscopy during induction of anesthesia in patients undergoing coronary artery bypass graft surgery: comparison of midazolam with propofol.

BACKGROUND: Near-infrared spectroscopy (NIRS) continuously measures regional cerebral oxygen saturation (rSO2) noninvasively and has been shown to detect even small changes in cerebral oxygen supply-demand balance. Although widely used, only the effect of midazolam on cerebral blood flow has been studied in humans and evidence is lacking about its effect on cerebral metabolic rate. We therefore evaluated the effect of midazolam on cerebral oxygen supply-demand balance with NIRS. METHODS: Sixty patients undergoing elective coronary artery bypass graft surgery were randomly allocated into either midazolam (n = 30) or propofol (n = 30) group. rSO2 was recorded before induction while patients were breathing room air as baseline, after pre-oxygenation with 100% oxygen, after administration of either midazolam or propofol, after completion of administration of sufentanil and after tracheal intubation. Hemodynamic variables including cardiac index and mixed venous oxygen saturation were recorded at the same time points. RESULTS: rSO2 and hemodynamic variables were similar between the groups throughout the study period. After pre-oxygenation, rSO2 significantly increased compared to baseline in each group, and did not show any additional increase after administration of either midazolam or propofol and sufentanil in both groups. CONCLUSIONS: Midazolam preserves cerebral blood flow-metabolism coupling to a similar degree to propofol as assessed by near infrared spectroscopy.

Comparison of remifentanil and fentanyl for postoperative pain control after abdominal hysterectomy.

PURPOSE: In this randomized, double-blind study, we investigated the analgesic efficacy and side effects of continuous constant-dose infusions of remifentanil after total abdominal hysterectomy and compared it to fentanyl. MATERIALS AND METHODS: Fifty-six adult female patients scheduled for elective total abdominal hysterectomy were enrolled in this study. Patients were randomly assigned to two groups according to fentanyl (group F, n=28) or remifentanil (group R, n=28) for postoperative analgesia. Patients in group F were given fentanyl intravenously with an infusion rate of fentanyl 0.5 microg/kg/hr; group R was given remifentanil with an infusion rate of remifentanil 0.05 microg/kg/min for 2 days. Pain intensity at rest, occurrence of postoperative nausea and vomiting (PONV), dizziness, pruritus, and respiratory depression were assessed 1 hr after arrival at the post-anesthesia care unit, at 6; 12; 24; and 48 hr post-operation and 6 hr post-infusion of the study drug. Pain was evaluated by using visual analogue scale (VAS; 0-10). The time that patients first requested analgesics was recorded as well as additional analgesics and antiemetics. RESULTS: There were no significant differences in VAS, time to first postoperative analgesics, and additional analgesics between the 2 groups. The incidences and severities of PONV and opioid related side effects were not different between the groups; however, there were 3 episodes (10.7%) of serious respiratory depression in group R. CONCLUSION: Continuous infusion technique of remifentanil did not reveal any benefits compared to fentanyl. Furthermore, it is not safe for postoperative analgesia in the general ward.

H2O2 enhances Ca2+ release from osteoblast internal stores.

The physiological activity of osteoblasts is known to be closely related to increased intracellular Ca2+ activity ([Ca2+]i) in osteoblasts. The cellular regulation of [Ca2+]i in osteoblasts is mediated by Ca2+ movements associated with Ca2+ release from intracellular Ca2+ stores, and transmembrane Ca2+ influx via Na+-Ca2+ exchanger, and Ca2+ ATPase. Reactive oxygen species, such as H2O2, play an important role in the regulation of cellular functions, and act as signaling molecules or toxins in cells. In this study, we investigated the effects of H2O2 on cellular Ca2+ regulation in osteoblasts by measuring intracellular Ca2+ activities using cellular calcium imaging techniques. Osteoblasts were isolated from the femurs and tibias of neonatal rats, and cultured for 7 days. The cultured osteoblasts were loaded with a Ca2+-sensitive fluorescent dye, Fura-2, and fluorescence images were monitored using a cooled CCD camera, and subsequently analyzed using image analyzing software. The results obtained are as follows: (1) The osteoblasts with lower basal Ca2+ activities yielded a transient Ca2+ increase, a Ca2+ spike, while osteoblasts with higher basal Ca2+ activities showed a continuous increase in [Ca2+]i leading to cell death. (2) Ca2+ spikes, generated after removing Na+ from superfusing solutions, were blocked by H2O2 and this was followed by a sustained increase in Ca2+ activity. (3) ATP- induced Ca2+ spikes were inhibited by pretreating with H2O2 and this was followed by a continuous increase of [Ca2+]i. When cells were pretreated with the exogenous nitric oxide (NO) donor S-Nitroso-N-acetylpenicilance (SNAP, 50 microM), treatments of ATP (1 mM) induced a Ca2+ spike-like increase, but [Ca2+]i did not return to the basal level. (4) The expression of inositol- 1,4,5-triphosphate receptor (IP3R) was enhanced by H2O2. Our results suggest that H2O2 modulates intracellular Ca2+ activity in osteoblasts by increasing Ca2+ release from the intracellular Ca2+ stores.