Low-dose Simvastatin Increases Skeletal Muscle Sensitivity to Caffeine and Halothane.

Objective To determine whether the myotoxic side effects of statin simvastatin affect skeletal muscle's sensitivity to caffeine and halothane.Methods Primary cultured neonate rat skeletal myotubes were treated with 0.01-5.0 µmol/L simvastatin for 48 hours. MTT was used to evaluate cellular viability. The gross morphology and microstructure of the myotubes were observed with a light and electron microscope, respectively. The intracellular calcium concentrations ([Ca2+]i) at rest and in response to caffeine and halothane were investigated by fluorescence calcium imaging. Data were analyzed by analysis of variance (ANOVA) test.Results Simvastatin (0.01-5.0 µmol/L) decreased myotube viability, changed their morphological features and microstructure, and increased the resting [Ca2+]i in a dose-dependent manner. Simvastatin did not change myotube's sensitivity to low doses of caffeine (0.625-2.5 mmol/L) or halothane (1.0-5.0 mmol/L). In response to high-dose caffeine (10.0 mmol/L, 20.0 mmol/L) and halothane (20.0 mmol/L, 40.0 mmol/L), myotubes treated with 0.01 µmol/L simvastatin showed a significant increase in sensitivity, but those treated with 1.0 µmol/L and 5.0 µmol/L simvastatin showed a significant decrease. The sarcoplasmic reticulum Ca2+ storage peaked in the myotubes treated with 0.01 µmol/L simvastatin, but it decreased when cells were treated with higher doses of simvastatin (0.1-5.0 µmol/L).Conclusions The myotoxic side effect of simvastatin was found to change the sensitivity of myotubes in response to high-dose caffeine and halothane. When dose was low, sensitivity increased mainly because of increased Ca2+ content in the sarcoplasmic reticulum, which might explain why some individuals with statin-induced myotoxic symptoms may show positive caffeine-halothane contracture test results. However, when the dose was high and the damage to the myotubes was severer, sensitivity was lower. It is here supposed that the damage itself might put individuals with statin-induced myotoxic symptoms at greater risks of presenting with rhabdomyolysis during surgery or while under anesthesia.

[Influence of different tranexamic acid administration methods during and after cardiac surgery on coagulation function and postoperative blood loss].

OBJECTIVE: To evaluate the influence of different tranexamic acid administration methods during and after cardiac surgery with cardiopulmonary bypass(CPB) on coagulation function and postoperative bleeding. METHODS: Patients undergoing elective cardiac surgery with use of CPB (n=60) were randomized in a double-blind fashion to one of two treatment groups:group A(n=30) , administered with tranexamic acid 10 mg/kg (intravenous injection slowly before skin incision) , followed by infusion of normal saline until postoperative 12 hours;and group B(n=30) , administered with tranexamic acid 10 mg/kg(intravenous injection slowly before skin incision) , followed by infusion of tranexamic acid 1 mg/(kg·h) until postoperative 12 hours. Hemoglobin, platelet count, and coagulation function were assessed before anesthesia induction, after surgery, 8am next day and 24 hours after surgery. Bleeding, allogeneic blood transfusion, and fluid infusion during the postoperative 24 hours were recorded. RESULT: No differences were found between groups in terms of coagulant function, postoperative bleeding, allogeneic blood transfusion, and fluid infusion(P>0.05) . CONCLUSION: Compared with intraoperative administration alone, prolonged treatment with tranexamic acid after cardiac surgery shows no advantage because it can not further improve coagulant function, reduce bleeding, or reduce allogeneic blood transfusion.

[Analgesic effect of calpain inhibitor ALLN on the zymosan-induced paw inflammatory pain and its effect on the expression of cyclooxygenase-2 in the spinal dorsal horn].

OBJECTIVE: To examine the analgesic effect of calpain inhibitor ALLN on the zymosan-induced paw inflammatory pain and its effect on the expression of cyclooxygenase-2 (COX-2) in the spinal dorsal horn. METHODS: Forty-eight Sprague-Dawley rats were equally divided into three groups: control group, sham-operated group, and zymosan group. According to Meller's method, zymosan (1.25 mg) was injected intraplantarly to induce paw inflammation in zymosan group; an equal volume of PBS was administered in the sham-operated group. Mechanical withdrawal threshold (MWT) and maximum thickness of paw were tested or measured before and 0.5, 1, 2, 4, 8, and 24 hours after injection. All rats were killed at different occasions following surgery to examine calpain activity in the spinal dorsal horn with Western blot analysis. Another sixty-four Sprague-Dawley rats were divided into three groups: sham-operated group, zymosan-induced paw inflammation with intraperitoneal dimethyl sulphoxide (DMSO) treatment group, and zymosan-induced paw inflammation with intraperitoneal calpain inhibitor ALLN treatment group. MWT and maximum thickness of paw were tested or measured before and 0.5, 1, 2, 4, 8, and 24 hours after injection. All rats were killed at different occasions following surgery to examine the COX-2 expression in the spinal dorsal horn with Western blot analysis. RESULTS: MWT significantly decreased in the rats with zymosan-induced paw inflammation, while the maximum thickness of paw significantly increased, compared with control and sham-operated rats (P < 0.05). Calpain in the ipsilateral spinal dorsal horn was dramatically activated after zymosan injection (P < 0.01). Intraperitoneal ALLN injection significantly increased zymosan-induced MWT and decreased paw edema at the same time points after zymosan injection compared with DMSO treatment group (P < 0.05). Meanwhile, calpain inhibitor ALLN treatment significantly decreased the COX-2 expression in the spinal dorsal horn compared with DMSO treatment (P < 0.01). CONCLUSION: Administration of calpain inhibitor ALLN is effective to attenuate zymosan-induced paw inflammatory pain. Calpain activation may be one aspect of the signaling cascade that increases the COX-2 expression in the spinal cord and contributes to mechanical hyperalgesia after peripheral inflammatory injury.

[Application of lumber plexus blockade for hip fracture repair in elderly patients].

OBJECTIVE: To evaluate the lumber plexus blockade as anesthesia technique for hip fracture repair in elderly patients. METHODS: We retrospectively analyzed the peri-operative data of 87 hip fracture patients, aged 70 years or older, who underwent surgical repair at our hospital between 2003 and 2006. Patients were divided into three groups according the anesthesia techniques applied: general anesthesia (GA) group (n=21), epidural anesthesia (EA) group (n=37), and lumber plexus blockade (LPB) group (n=29). RESULTS: The peri-operative data were comparable among three groups, except that intra-operative the dosage of fentanyl was significantly lower in LPB group compared with in GA group(P0.05), and the blood urea nitrogen 1 day after surgery was significantly increased in GA group(P0.05). CONCLUSION: Lumber plexus blockade combined with small-dose intravenous anesthesia is an optional anesthetic technique for elderly patients undergoing hip fracture repair.

[Application of propofol target controlled infusion combined with dribbled and nebulized lidocaine in tracheal intubation under spontaneous respiration].

OBJECTIVE: To evaluate the value of propofol target-controlled infusion combined with dribbled and nebulized lidocaine in tracheal intubation under spontaneous breathing. METHODS: Totally 40 elective surgery patients to accept tracheal intubation under unconsciousness and spontaneous breathing were randomly divided into 2 groups: 6-8 cm of endotracheal tube was inserted subglottic ally in the complete intubation group (n=20) while 3-4 cm was inserted temporarily in the partial intubation group (n=20). RESULTS: The tracheal intubation was successfully completed under spontaneous breathing in all patients; meanwhile,the hemodynamic status was stable without any severe respiratory complications. Eleven patients suffered from moderate coughing response in the complete intubation group while no such response was noted in the partial intubation group (P<0.01). CONCLUSIONS: Application of propofol target-controlled infusion combined with dribbled and nebulized lidocaine provides a good condition for tracheal intubation under unconsciousness and spontaneous breathing. The partial intubation can effectively prevent the occurrence of coughing response.

[Effects of residual paralysis after a single intubating dose of rocuronium on postoperative pulmonary function of patients undergoing laparoscopic gynecological surgeries].

OBJECTIVE: To evaluate the residual paralysis after a single intubating dose of rocuronium and its effect of residual paralysis after a single dose of rocuronium on the postoperative pulmonary function of patients undergoing laparoscopic gynecological surgeries. METHODS: Sixty American Society of Anesthesiologists (ASA) I - II patients undergoing laparoscopic gynecological surgeries were randomly divided into rocuronium (R) group (n = 30) and rocuronium + neostigmine (R + N) group (n = 30).All patients received midazolam (0.02 mg/kg), fentanyl (1 microg/kg), propofol(1.5-2 mg/kg), and rocuronium (0.6 mg/kg) to facilitate tracheal intubation and no more relaxant thereafter. Anesthesia was maintained with isoflurane and nitrous oxide in oxygen (N(2)O:O(2) = 1:1). At the end of the procedure, neuromuscular blockade was not reversed in R group, while antagonism was accomplished with neostigmine (0.04 mg/kg) and atropine (0.02 mg/kg) in R + N group. Immediately after tracheal extubation and on arrival in the PACU, the train-of-four (TOF) ratio at the adductor pollicis of all patients were measured using acceleromyography. Forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), and peak expiratory flow rate (PEFR) of all patients were measured using spirometry before surgery, after administration of midazolam and fentanyl, immediately after tracheal extubation, on arrival in the PACU, and after the TOF ratio recovered to 1.0. The TOF ratio and pulmonary function between two groups were compared. RESULTS: Immediately after tracheal extubation and on arrival in the PACU, the mean TOF ratio in R group was significantly lower than that in R + N group (P < 0.05). The mean time to achieve TOF ratio of 0.9 and 1.0 in R group was significantly longer than in R + N group (P < 0.05). Immediately after tracheal extubation and on arrival in the PACU, FVC, FEV(1), and PEFR were significantly lower in R group than in R + N group (P < 0.05). FVC, FEV(1), and PEFR after administration of midazolam and fentanyl and after TOF ratio recovered to 1.0 were significantly lower than the baseline values in all patients (P < 0.01). CONCLUSIONS: After a single intubating dose of rocuronium, residual paralysis exists in the majority of patients undergoing laparoscopic gynecological surgeries. The pulmonary function is impaired after the surgery, even after recovery of TOF ratio to 1.0.

[Perioperative hemodynamics in pheochromocytoma secreting different types of catecholamine].

OBJECTIVE: To analyze the characteristics of perioperative hemodynamics in pheochromocytoma secreting different types of catecholamine, and to discuss how to improve the hemodynamics. METHODS: The clinical data of 202 patients with pheochromocytoma who had received operation were analyzed. Three classification systems were used to divided the patients: they were, firstly, divided into high and low epinephrine secreting groups (E(high) and E(low)) according to the 24 hours urine catecholamine quantitation; secondly, into high and low norepinephrine secreting groups (NE(high) and NE(low)) according to 24-h urine norepinephrine quantitation; and thirdly, into high and low dopamine secreting groups (DA(high) and DA(low)) according to the 24 hours urine dopamine quantitation. Relationship between the characteristics of perioperative hemodynamics and catecholamine secreting types were analyzed. RESULTS: The highest preoperative systolic blood pressure values of E(high) and NE(high) groups were (201 +/- 40) mm Hg and (205 +/- 38) mm Hg, both significantly higher than those of the E(low) and NE(low) groups [(183 +/- 43) mm Hg, P = 0.003 and (181 +/- 43) mm Hg, P = 0.000]. The range of systolic blood pressure fluctuation during the operation of the E(high) group was 108 +/- 39 mm Hg, significantly larger than that of the E(low) group (91 +/- 33 mm Hg, P = 0.001). The incidence rates of persisting postoperative hypotension of the NE(high) and DA(high) groups were 23.3% (20/86) and 32.7% (17/52) respectively, both higher than those of the NE(low) and DA(low) groups [2.6% (3/116) and 4.0% (6/150) respectively, P = 0.000 and P = 0.000]. CONCLUSION: Different characteristics of perioperative hemodynamics are present in pheochromocytoma secreting different types of catecholamines. Patients with highly epinephrine secreting pheochromocytoma are apt to have larger blood fluctuation during the operation. Patients with highly norepinephrine and dopamine secreting pheochromocytoma are apt to suffer from persisting postoperative hypotension.

[Effects of melatonin on the voltage-gated delayed rectifier potassium channels of cultured hippocampal neurons of new-born rats].

OBJECTIVE: To investigate the effects of melatonin on voltage-gated delayed rectifier potassium channels. METHODS: Hippocampus neurons were obtained from newborn Wistar rat and cultured. Primary cultured for 7 to 12 days of new-born Wistar rat were selected as objectives. Patch clamp whole-cell recording technique was used on the hippocampus neurons cultured for 7 to 12 day. to record the delayed rectifier potassium current to analyze the basic electrophysiological characteristics. The effects of melatonin of the concentrations of 1 nmol/L, 10 nmol/L, 100 nmol/L, 1 mol/L, 10 mol/L, 100 mol/L, and 1 mmol/L on the amplitudes and kinetics of delayed rectifier potassium currents were investigated. RESULTS: With different voltage protocols and specific blockers of potassium channel (4-AP and TEA) a delayed rectifier potassium current that activated and inactivated slowly and had the outward rectifying characteristics (Ik) from the outward potassium currents in cultured new-born hippocampus neurons was separated. The effect of melatonin on the delayed rectifier channel was rapid, reversible and voltage-dependent Melatonin had no effect on the kinetic characteristics of the I -V curve. Melatonin increased the potassium current concentration-dependently. 1 - 100 nmol/L melatonin increased the amplitude of potassium current gradually; the effects of 1 - 100 micromol/L melatonin on the potassium current increased concentration-dependently, while the action of 1 mmol/L melatonin decreased. CONCLUSION: Melatonin reversibly increases the rectifier delayed potassium currents of the cultured hippocampus neurons of new-born rat. This may be involved in some aspects of physiological and pathological significance of potassium currents.

[Application of caffeine-halothane contracture test in the diagnosis of malignant hyperthermia].

OBJECTIVE: To explore the application of caffeine-halothane contracture test (CHCT) in the confirmation of malignant hyperthermia (MH). METHODS: One patient who underwent radical gastrectomy presented with clinical manifestations of MH during routine intravenous-inhalation anesthesia process. Isoflurane inhalation and the operation were ceased immediately and emergency management approaches such as physical cooling therapy were taken. Meanwhile, the levels of serum creatine kinase (CK), serum myoglobin, and urinary myoglobin were examined and rectus abdominis was taken and then CHCT was performed to confirm the clinical diagnosis. Total genome was extracted from the patient and then exons 2-18, 39-46, and 90-104 of ryanodine receptor 1 (RYR1) gene were screened to detect mutations using DNA sequencing technique. RESULTS: The patient was diagnosed as MH episode by clinical characteristics and postoperatively continuous elevation of the levels of CK, serum myoglobin, and urinary myoglobin (30 times higher than normal level). Despite halothane test was negative, the diagnosis of MH was verified by the positive result of caffeine test. DNA sequencing of RYR1 gene of the patient revealed c. 6724C > T (p. T 2 206M). CONCLUSION: CHCT can be used to confirm the diagnosis of MH.

Postoperative neuropsychological change and its underlying mechanism in patients undergoing coronary artery bypass grafting.

BACKGROUND: The high incidence of neuropsychologic deficits after cardiac surgery, including cognitive dysfunction and mood status, has significantly influenced the prognosis, outcome of treatment and long-term quality of life of patients. With a circadian secretion pattern, melatonin and cortisol are capable of modulating the human physiological processes and neuropsychological status, whereas disorder of their secretion pattern may lead to many diseases. However, it is unclear whether neuroendocrine variations are related to the neuropsychologic status in patients undergoing coronary artery bypass grafting (CABG). METHODS: Forty male patients scheduled for CABG with hypothermic cardiopulmonary bypass (CPB) (n = 20) or off-pump coronary artery bypass (OPCAB) (n = 20) were studied. Blood samples were taken intraoperatively at specific time-points and every 3 hours within the first postoperative 24 hours to determine plasma concentrations of melatonin and cortisol. A neuropsychologic test battery including depression and anxiety was administered preoperatively and 7 to 10 days postoperatively. Statistical methods included the nonparametric analysis, multiple linear regression and cosinor analysis. RESULTS: The patients in the CPB group exhibited more severe neuropsychologic deficits and more anxious than those in the OPCAB group after surgery. In both groups, patients were more depressed postoperatively than preoperatively and recovered 3 months after surgery. Depression and anxiety were correlated with some factors of cognitive dysfunctions. In the postoperative 24 hours, 2 patients in the CPB group, and 6 patients in the OPCAB group showed a circadian rhythm of melatonin secretion. As for cortisol secretion, there were 3 patients in the CPB group and 7 in the OPCAB group respectively. Parameters of circadian rhythm of melatonin in the CPB group and those of secretion rhythm of cortisol in both groups were correlated with depression and some neuropsychologic tests. CONCLUSIONS: The incidence of neuropsychological deficits was higher in patients receiving CABG with CPB than in those without CPB. The status of mood may contribute to the perioperative cognitive dysfunctions. The disordered circadian rhythm of melatonin secretion in patients undergoing CABG with CPB and the disordered cortisol secretion may correlate directly or indirectly through mood with neuropsychological deficits.

Malignant hyperthermia in China.

Malignant hyperthermia has rarely been reported in China. We report the first case of malignant hyperthermia, verified by caffeine-halothane contracture test and genetic testing, in a Chinese patient.

[Anesthetic management of laparoscopic adrenalectomy for pheochromocytoma].

OBJECTIVE: To investigate the anesthetic management features of laparoscopic adrenalectomy for pheochromocytoma. METHODS: Twelve patients scheduled for laparoscopic adrenalectomy for pheochromocytoma under general anesthesia were allocated into group 1, while another 12 patients who received transabdominal adrenalectomy for pheochromocytoma under general anesthesia were selected as group 2. The hemodynamic changes and the postoperative recovery profiles between the two groups were compared. RESULTS: Hemodynamic fluctuation occurred during carbon dioxide insufflation and tumor manipulation in group 1. However, there were no differences between the two groups. Duration of post operative recovery and hospital stay as well as requirement of analgesics in group 1 were significantly lower than those in group 2 (P < 0.05). CONCLUSION: Hemodynamic fluctuation still exists during laparoscopic adrenalectomy for pheochromacytoma. However, patients undergoing such surgical procedure recover faster as compared with open surgery.

Forced-air warming and fluid warming minimize core hypothermia during abdominal surgery.

OBJECTIVE: To evaluate the effect of intraoperative combined forced-air warming and fluid warming system on patient's core temperature, blood loss, transfusion demand, extubation time, and incidence of postoperative shivering. METHODS: Forty patients with American Society of Anesthesiologists physical status I and II, aged 18-70 years, scheduled for elective abdominal surgery were randomly assigned to receive intraoperative warming from a forced-air blanket and fluid warming system or conventional cotton blanket, 20 in each group. The core temperature was recorded every 20 minutes during the operation, as well as the blood loss, blood transfusion, extubation time, and incidence of postoperative shivering. RESULTS: The core temperature at the end of the surgery in the warming group was significantly different from that in the control group (36.4 +/- 0.4 degrees C vs. 35.3 +/- 0.5 degrees C, P < 0.001). Application of intraoperative warming significantly shortened the time between the end of the surgery and extubation (P < 0.01). Postoperative shivering occurred in 30% of the patients in the control group compared to no patient in the warming group (P < 0.01). CONCLUSION: Active warming with air-forced blanket and fluid warming system provides sufficient heat to prevent hypothermia during abdominal surgery.

[Perioperative cortisol circadian secretion and neuropsychological states in patients undergoing coronary artery bypass grafting surgery].

OBJECTIVE: To investigate the relationship between the circadian rhythm of perioperative cortisol secretion and neuropsychological states in patients undergoing coronary artery bypass grafting surgery. METHODS: Forty male patients scheduled for elective coronary artery bypass grafting (CABG) under hypothermic cardio-pulmonary bypass (CPB) or off-pump were enrolled in this study. They were allocated into CPB group or off-pump group with 20 patients in each group. Blood samples were withdrawn during surgery at specific time-points and every 3 h for 24 h in the immediate postoperative period. Plasma cortisol was measured by radioimmunoassay. All subjects were investigated preoperatively as well as 7 to 10 d and 3 months postoperatively with a comprehensive neuropsychologic assessment, while depression and anxiety were assessed by Self-Rating Depression Scale and the State-Trait Anxiety Inventory respectively. RESULTS: During postoperative 24 h, three patients in the CPB group and 7 patients in the off-pump group were demonstrating a circadian secretion pattern, while they were disturbed in the remaining patients in both groups. Postoperative depression scores of patients in both groups were significantly higher than preoperative values. Postoperative anxiety scores of patients in the CPB group were significantly higher than those in the off-pump group. The CABG with CPB patients showed a significant deficit in the Digit Span subtest of the WAIS-R and the Stroop colour word interference test. The disturbed cortisol circadian secretion in the CPB group correlated with depression and the Stroop colour word interference test, whereas in the off-pump group it correlated with depression, Digit Span subtest (forward), symbol digit modalities test and the Stroop colour word interference test. Degree of depression correlated with some items of cognitive dysfunctions. CONCLUSION: Perioperative secretion rhythm of cortisol in patients undergoing CABG surgery with CPB or off-pump was disturbed. The disordered cortisol may correlate directly or indirectly through mood with neuropsychological deficits.

Concentrations of propofol in cerebral spinal fluid: target-controlled infusion.

BACKGROUND: Although the performance of target-controlled infusion (TCI) have been studied extensively, the accuracy and safety of a TCI system that targets the effect site remains to be demonstrated. This study was to investigate the relations of TCI of propofol to its concentrations in cerebral spinal fluid (CSF), the effect-site concentrations and bispectral index (BIS). METHODS: Twelve mongrel dogs were used for investigations. The target effect-site concentration was set at 3 microg/ml and the infusion was lasted for 15 minutes. CSF and blood samples were then collected and propofol concentrations were determined by using high performance liquid chromatography with fluorescence detection. BIS and hemodynamic data were monitored continuously. RESULTS: The predicted plasma concentrations were generally overestimated. Median performance error (MDPE) and absolute median performance error (MDAPE) were -10.0% and 29.9% respectively. Propofol CSF concentrations were much lower than its effect-site concentrations. Changes in BIS were consistent with propofol concentrations in CSF, both of which changed direction at 5 minutes while the effect-site concentrations relatively lagged behind. Better correlation (r(2) = 0.9195) was found between BIS and CSF concentrations, when compared with that between BIS and effect-site concentrations (r(2) = 0.554). CONCLUSION: With 1% enflurane inhaled, the inconsistency of drug effect to the effect-site concentrations may result from inaccuracy of pharmacokinetic parameters. CSF may show effect-site concentrations more accurately than plasma when using target effect-site concentration infusion.

[Patient-controlled analgesia with tramadol and tramadol/droperidol mixture after abdominal hysterectomy: a double-blinded, randomized controlled trial].

OBJECTIVE: To compare the clinical efficacy and side effects of tramadol and the mixture of tramadol and droperidol for postoperative patient-controlled analgesia (PCA). METHODS: Sixty female patients, aged 18 - 65, scheduled for elective abdominal total hysterectomy with inhalational general anesthesia (induced with fentanyl and propofol, maintained with O(2)-N(2)O and enflurane or isoflurane supplemented by intermittent iv fentanyl and vercuronium for muscle relaxation) were allocated into 2 groups of 30 patients in a random and double blind manner: group 1 (20 mg tramadol) and group 2 (20 mg tramadol plus 0.1 mg droperidol), both with a lockout time of 10 minutes. The VAS, analgesic doses, and side effects were observed 4, 8, 12, 20, 28, and 36 hours after operation respectively. RESULTS: Adequate analgesia was achieved with tramadol or the mixture of tramadol and droperidol. The nausea rates and vomiting rates at any time point in the group 2 were all significantly lower than those in the group 1 (all P < 0.05). Ten patients in the group 1 needed treatment of metoclopramide, and none of patients in the group 2 needed antiemetic (P < 0.01). No significant differences were observed in VAS, sedation score or vital signs (all P > 0.05). CONCLUSION: Providing a similar quality of analgesia with less nausea and vomiting as well as little need for sedative, the combination of tramadol and droperidol is superior to tramadol alone for post-operative PCA.

[Perioperative melatonin circadian secretion in patients undergoing coronary artery bypass grafting surgery].

OBJECTIVE: To investigate the circadian rhythm of perioperative melatonin secretion in patients undergoing coronary artery bypass grafting surgery. METHODS: Forty male patients scheduled for elective coronary artery bypass grafting surgery (CABG) under hypothermic cardiopulmonary bypass (CPB) or off-pump were allocated into two groups of 20 patients: CPB group and off-pump group. Blood samples were withdrawn from all patients immediately before the induction of anesthesia (baseline), 10 min after the induction of anesthesia, 10 min after heparinization, 30 min after commencement of CPB (or 2h after skin incision), before reversal of heparin with protamine, at the end of surgery, and. every 3 hours after operation until the twenty-fourth hour. The plasma concentration of melatonin was measured by using enzyme-linked immunosorbent assay. RESULTS: The plasma melatonin concentrations during and after CPB were higher than the baseline value in the CPB group. There were no differences in the melatonin concentrations in the off-pump group. In the CPB group the melatonin concentrations after induction, during CPB, and after CPB were 7.2 +/- 3.4, 10.5 +/- 5.2, and 9.5 +/- 4.0 respectively, all significantly higher than those in the off-pump (5.5 +/- 2.5, 6.3 +/- 2.0, and 5.7 +/- 2.1 respectively, all P < 0.05). During the twenty-four hours after operation, two patients in the CPB group and six patients in the off-pump group showed circadian rhythm of melatonin secretion. CONCLUSION: The perioperative circadian rhythm of melatonin secretion in patients undergoing CABG surgery with CPB or off-pump is disturbed, however relatively more patients under off-pump group regain secretion rhythm of melatonin in the immediate postoperative period. CPB may be one of the reasons for perioperative melatonin circadian secretion disturbance.

[Use of blood salvage machine in oncologic surgeries: a clinical observation of 13 cases].

OBJECTIVE: To evaluate the effects on blood sparing and risk of hematogenous tumor dissemination of the use of blood salvage machine in oncologic surgeries. METHODS: The clinical data of 13 patients, 6 with malignant tumors and 7 with benign tumors, who received the use of blood salvage machine during oncologic surgeries based on informed consent, were analyzed. RESULTS: In total 42,575 ml of packed red blood cells were collected during surgery with a mean value of 3 275 ml (400 - 1500 ml) per patient. The average amount of allogenic transfusion per patient was 1 530 ml (0 - 8,000 ml). The number of blood salvage machine use in oncologic surgeries accounted for 8.6% (13/152) of the total number of blood salvage machine use in surgeries in that period. The perioperative mortality rate of the oncologic surgeries with the use of blood salvage machine was 7.7% (1/13). The post-operative metastasis rate of liver and lung was 15.4% (2/13). CONCLUSION: The use of blood salvage machine during oncologic surgeries improves the blood sparing effect. However, it cannot be used routinely, since it may result in hematogenous tumor cell dissemination.

[Effect of volume replacement with hydroxyethyl starch solution for blood loss on splanchnic oxygenation in patients undergoing cytoreductive surgery for ovarian carcinoma].

OBJECTIVE: To investigate the effect of medium molecular weight hydroxyethyl starch solution (HES) administered as replacement for estimated blood losses (EBL) during cytoreductive surgery for ovarian carcinoma on splanchnic oxygenation. METHODS: Cytoreductive surgery was operated upon forty-two patients with ovarian carcinoma. As soon as the EBL was higher than 10% but less than 20% of the estimated blood volume, the patients were randomly assigned to receive a volume of lactated Ringer's solution (LRS) equal to three times the EBL (LRS group, n = 22) or a volume of 6% HES equal to the EBL (HES group, n = 20). Tissue oxygenation was assessed indirectly by measuring the tonometric parameters of stomach, including difference between gastric intramucosal PsCO(2) and arterial PaCO(2) (Ps-aCO(2) gap), gastric intramucosal pH (pHi) and arterial lactate acid concentration 30 min after induction of anesthesia (baseline value), 1 h and 2 h after skin incision, and at the end of surgery. RESULTS: At the end of surgery, the Ps-aCO(2) gap was 8.7 mm Hg +/- 1.6 mm Hg in the HES group, significantly lower than that in the LRS group (18.74 mm Hg +/- 4.4 mm Hg, P < 0.01), while the pHi in the HES group was 7.30 +/- 0.05, significantly higher than that in the LRS group (7.21 +/- 0.07, P < 0.01). There was no significant difference in arterial lactate acid concentration between the two groups. CONCLUSION: In patients undergoing major surgery, volume resuscitation with medium molecular weight HES improves the splanchnic blood flow and tissue oxygenation.

[Perioperative melatonin secretion rhyme in patients undergoing coronary artery bypass grafting surgery].

OBJECTIVE: To investigate perioperative patterns of melatonin and cortisol secretion rhyme in patients undergoing coronary artery bypass grafting surgery. METHODS: Eleven male patients scheduled for elective coronary artery bypass grafting surgery (CABG) under hypothermic cardiopulmonary bypass (CPB) were enrolled in the study. Anesthesia was induced and maintained with propofol (3 mg.kg-1.h-1) and supplemented with fentanyl (15 micrograms/kg). Blood samples were taken during surgery at specific time-points and every 3 h in the immediate postoperative period and postoperative day 2 and day 3. Plasma melatonin and cortisol levels were measured by radioimmunoassay and enzyme-linked immunosorbent assay respectively. RESULTS: During surgery, plasma melatonin levels were below the minimum sensitivity level but low levels, without circadian variation, were measured during the immediate postoperative period. During postoperative day 2 and day 3, circadian secretion patterns of melatonin were present in 10 patients and showed an inverse correlation with light intensity exposed (r = -0.480, P = 0.01). Plasma cortisol levels in the immediate postoperative period were significantly higher than those before induction of anesthesia (P < 0.01). During postoperative day 2 and day 3, only 3 patients regained circadian secretion of cortisol. CONCLUSIONS: It is concluded that melatonin and cortisol secretion are disrupted during cardiac surgery and in the immediate postoperative period.