OBJECTIVETo investigate the effect of different fresh gas flow (FGF) rates on isoflurane pharmacokinetics during anesthesia induction.

METHODSSixty female patients (ASA class I-II, age range of 18-49 years) scheduled for gynecological laparoscopic surgery were randomly divided into groups I, II, and III (n=20) for isoflurane inhalation with FGF rate of 1, 2, and 3 L/min, respectively. Each group was further divided into two equal subgroups according to the setting concentration of the isoflurane vaporizer at 1% (groups I 1, II 1, and III 1) and 2% (groups I 2, II 2, and III 2). Isoflurane with different setting concentrations was administered under different FGFs in the patients after tracheal intubation following anesthesia induction, and the inspiratory concentration (CIiso) and expiratory concentration (CEiso) of isoflurane in the airway were monitored and recorded every 3 min for totalling 18 min, with the observation time points marked as T1 to T6, respectively.

RESULTSCIiso and CEiso varied significantly at different time points and between different subgroups (P<0.05). In each subgroup, CIiso and CEiso increased along with time and reached a relatively stable stage at 9 min, but failed to reach the setting concentration during the observation period. At different observation time points, CIiso and CEiso in the subgroups with setting isoflurane concentration of 2% were almost twice as much as that in the subgroups with setting isoflurane concentration of 1%.

CONCLUSIONSCIiso and CEiso increase along with time lapse in all the groups and reach a relatively stable stage at 9 min after inhalation initiation, but can not reach the setting concentration. The larger the FGF and setting concentration, the faster CIiso and CEiso increase.

Adolescent ; Adult ; Anesthesia ; methods ; Female ; Gases ; pharmacology ; Humans ; Isoflurane ; pharmacokinetics ; Middle Aged ; Respiration ; Time Factors ; Young Adult

OBJECTIVETo evaluate the effects of mechanical ventilation on pulmonary function during short duration of general anesthesia with tracheal intubation, and assess the safety of controlled spontaneous respiration during general anesthesia.

METHODSFifty-three adult patients (aged 18-55 years, ASA physical status I-II) scheduled for elective unilateral tympanoplasty were randomly assigned into mechanical ventilation group (group M, n=28) and spontaneous respiration group (group S, n=25). Anesthesia induction was performed in group M with intravenous propofol (2 mg/kg), fentanyl (3 microg

RESULTSA total of 43 patients (group M, n=23; group S, n=20) were included in the study with 10 dropouts due to failed attempt to obtain arterial blood samples (8 patients) or severe bucking during intubation (2 patients). No significant differences were found in HR and MAP between the two groups (P>0.05). The pH and SpO(2) [ (97.9-/+1.00)% at the lowest] and PaO(2) in group S were significantly lower and the PaCO(2) was higher than those in group M (P<0.05). In group S, the pH values were 7.274-/+0.025 and 7.331-/+0.039, PaCO(2) values were 60-/+6 and 53-/+5 mmHg, and PETCO(2) values were 53-/+ 6 and 48-/+7 mmHg, and the PaO(2) values were 143-/+37 and 165-/+49 mmHg immediately and 150 min after the intubation, respectively. These values were considered safe under the concept of permissive hypercapnia. No significant differences were found in the P(A-a)DO(2), RI, VD/VT and TFC between or within the two groups (P>0.05), nor were moving, bucking, swallowing and awareness recorded during the surgical procedures.

CONCLUSIONIn essentially normal lungs, short-term mechanical ventilation during general anesthesia with tracheal intubation does not damage the lung functions, and spontaneous respiration can offer sufficient oxygen supply without causing harmful carbon dioxide retention.

Adolescent ; Adult ; Anesthesia, General ; methods ; Female ; Humans ; Intubation, Intratracheal ; Lung ; physiology ; Male ; Middle Aged ; Respiration ; Respiration, Artificial ; methods ; Tympanoplasty ; methods ; Young Adult

OBJECTIVETo investigate the influence of chronic epilepsy on spatial memory retrieval in rats, and to evaluate the effects of TAK-147, an acetylcholinesterase inhibitor, and histidine, the precursor of histamine, on the amnesia induced by epilepsy.

METHODSAfter successfully trained in the 8-arm (4-arm baited) radial maze, the rats were ip injected with a subconvulsive dose of pentylenetetrazole (PTZ) every 48 h until fully kindled. Memory retrieval was tested at the same maze.

RESULTImpairment of memory retrieval was in a steady state 1 to 18 days after fully kindled, the ability of memory retrieval returned to the control level 31 days after fully kindled. TAK-147 showed an ameliorating effect on memory impairment induced by epilepsy, including reference and working memory in a dose-dependent manner. Histidine only ameliorated reference but not working memory.

CONCLUSIONPTZ-kindled seizure impair spatial memory retrieval, which it might be due to a decrease of brain acetylcholine and histamine induced by epilepsy.

Animals ; Benzazepines ; therapeutic use ; Chronic Disease ; Dose-Response Relationship, Drug ; Epilepsy ; psychology ; Male ; Maze Learning ; Memory Disorders ; drug therapy ; etiology ; Pentylenetetrazole ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the mechanisms of histamine on chronic epilepsy induced by pentylenetetrazole (PTZ).

METHODSTo induce chemical kindling, a subconvulsive dose (35mg/kg) of PTZ was ip injected every 48 h in rats. Behavior changes were observed for 30 min after every injection of PTZ.

RESULTIp injection of histidine or icv injection of clobenpropit inhibited the development of kindling induced by PTZ, presenting prolonged latency for myoclonic jerks and clonic generalized seizures and depressed seizure stages in a dose-dependent manner. H(3)receptor agonist, immepip, and histidine decarboxylase, alpha-fluoromethylhistidine reversed the ameliorating effect of clobenpropit on seizure development in a dose-dependent manner.

CONCLUSIONBrain histamine plays an important role in protection against myoclonic jerks and clonic generalized clonic seizures and its action may be via H(3)receptor.

Animals ; Brain ; physiology ; Chronic Disease ; Dose-Response Relationship, Drug ; Epilepsy ; chemically induced ; Histamine ; physiology ; Histidine ; pharmacology ; Imidazoles ; pharmacology ; Male ; Pentylenetetrazole ; pharmacology ; Piperidines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Thiourea ; analogs & derivatives ; pharmacology

OBJECTIVETo investigate the effect of different fresh gas flows (FGFs) on the pharmacodynamics of isoflurane during anesthesia induction.

METHODSSixty female ASA class I or II patients (aged from 18 to 49 years) scheduled for gynecologic laparoscopic surgery were randomly divided into groups I, II, and III (n=20). The FGFs for group I, II, and III was 1, 2 and 3 L/min, respectively, and each group was further divided into two equal subgroups according to the setting concentrations of isoflurane vaporizer (Co), which was 1% in groups I1, II1, and III1 and 2% in groups I2, II2, and III2. Isoflurane at different setting concentration was administered under different FGF in the patients after tracheal intubation following anesthesia induction. The systolic blood pressure (SBP), diastolic blood pressure (DBP), main arterial blood pressure (MAP), heart rate (HR) and bispectral index (BIS) were recorded before anesthesia induction and every 3 min after tracheal intubation. Patients given ephedrine and atropine were also recorded. The patients' consciousness during anesthesia were followed up and recorded. The inspiratory concentration (CIiso) and expiratory concentration (CEiso) of isoflurane in the airway were monitored and recorded every 3 min. The observation after intubation lasted for 18 min, during which stimulation of the patients was avoided, and the operation began after the observation.

RESULTSThere was a close correlation between BIS and CIiso and between BIS and CEiso (r=-0.904 and -0.893, respectively). The incidence of hypotension was significantly different between groups III and I (P<0.01), and between the subgroups in groups II and I (P<0.05). No bradycardia occurred and no consciousness reported awareness during anesthesia.

CONCLUSIONSBetween the completion of tracheal intubation and beginning of the surgery, 1% or 2% Co under a moderate FGF (1-3 L/min) may guarantee the patients' unconsciousness, but hypotension is less likely under a relatively low flow (1-2 L/min) than a higher flow (3 L/min). Higher FGF and Co result in faster induction of deep anesthesia and higher incidence of hypotension.

Adolescent ; Adult ; Anesthesia, Inhalation ; Anesthetics, Inhalation ; pharmacokinetics ; Female ; Humans ; Isoflurane ; pharmacokinetics ; Middle Aged ; Monitoring, Intraoperative ; methods ; Oxygen ; administration & dosage

BACKGROUNDDifficult airway remains not only a challenge to the anesthesiologists, but also a life-threatening event to the patients. Awake intubation is the principal choice to deal with difficult airway, and a key point for awake intubation is airway topical anesthesia. Yet, so far there is no ideal topical anesthesia approach for awake intubation. This study aimed at evaluating the effect of pressure-driven (by 10 L/min oxygen flow) lidocaine spray on airway topical anesthesia in order to find a powerful and convenient method for airway topical anesthesia for conscious sedation intubation.

METHODSThirty adult patients referred for elective surgery under general anesthesia, aged 18 - C60 years and Mallampati class I or II, were recruited for the study. Before topical anesthesia, the observer's assessment of alert and sedation (OAA/S) scale was controlled between 3 and 4 by intravenous midazolam (0.03 mg/kg), propofol (2 mg×kg(-1)×h(-1)) and remifentanil (0.05 µg×kg(-1)×min(-1)). Ten minutes after sedation, topical anesthesia was performed with the pressure-driven lidocaine spray; the driving pressure was achieved by an oxygen flow of 10 L/min. After topical anesthesia, tracheal intubation was performed and the intubation condition was assessed with modified the Erhan's intubation condition score by an experienced anesthesiologist, and a score of less than 10 was considered to be satisfactory. Attempts to intubate the patient were recorded, and the complications such as local anesthetic toxicity, mucosa injury, and respiration depression were also recorded. The mean arterial blood pressure (MAP), heart rate (HR) and pulse oxygen saturation (SpO2) were recorded at different time points before and after intubation. Patients were asked 24 hours after the operation whether they could recall the events during intubation.

RESULTSAll patients were intubated at the first attempt, the average intubation condition score was 7.0 ± 1.1, from 6 to 10, satisfied intubation condition. MAP and HR increased significantly but mildly immediately after the tracheal intubation (P < 0.05), and decreased to the pre-intubation level soon after intubation. There were no related complications and patients had no recall of the intubation procedures.

CONCLUSIONSTopical anesthesia with pressure driven 2% lidocaine spray, where pressure is achieved by 10 L/min oxygen flow, can offer satisfactory intubation conditions for conscious sedation intubation.

Adolescent ; Adult ; Anesthesia, Local ; methods ; Conscious Sedation ; methods ; Female ; Humans ; Intubation, Intratracheal ; methods ; Lidocaine ; administration & dosage ; therapeutic use ; Male ; Middle Aged ; Young Adult

BACKGROUNDWhether plasma can transfer the protective effect(s) of remote ischemic preconditioning (RIPC) between animals remains unresolved. We therefore investigated the effects of plasma collected 48 hours after transient limb ischemia on blood pressure recovery during myocardial ischemia reperfusion (IR) in homogenic rats.

METHODSPlasma was collected from Lewis rats, and the donor rats were randomly assigned to 2 groups: transient limb ischemia and control (n = 8 each). Transient limb ischemia was achieved by four cycles of 5-minute ischemia and 5-minute reperfusion by noninvasive ligation and deligation of the both legs using elastic rubber bands after anesthesia. In the control group, no ligation was performed. Forty-eight hours later, whole blood was collected, and the plasma spun off. Study Lewis rats underwent 30-minute left anterior descending coronary artery occlusion followed by 180-minute reperfusion, and were randomly assigned to 2 groups (group A and group B, n = 24 each), each further subdivided into 3 subgroups (n = 8 each). The subgroups of group A received normal saline (group A1) , plasma of control rats (group A2), plasma of transient limb ischemia rats (group A3) respectively at 1 hour before IR; the subgroups of group B received normal saline (group B1), plasma of control rats (group B2), plasma of transient limb ischemia rats (group B3) respectively at 24 hours before IR. BIOPAC systems were used to measure hemodynamics of rats during myocardial ischemiareperfusion.

RESULTSSystolic blood pressure (SBP) after IR in group B3 was different from that in groups B1 and B2 (B3 vs. B1, P = 0.007; B3 vs. B2, P = 0.039) at the beginning of reperfusion and 30 minutes after reperfusion. SBP was higher in group B3 than in groups B1 and B2 at the beginning of perfusion (B3 vs. B1, P = 0.010; B3 vs. B2, P = 0.002) and 30 minutes after reperfusion (B3 vs. B1, P = 0.001; B3 vs. B2, P = 0.001). SBP did not differ among subgroups A1, A2 and A3. Diastolic blood pressure and heart rate did not change in group A or group B.

CONCLUSIONSThe transfusion of plasma collected 48 hours after transient limb ischemia into homogenic rats 24 hours before IR can improve the SBP recovery during reperfusion. This may suggest that cardioprotective effect of late phase of RIPC is transferable via plasma.

Animals ; Blood Pressure ; physiology ; Extremities ; blood supply ; Ischemia ; Ischemic Preconditioning ; Male ; Plasma ; Rats ; Rats, Inbred Lew ; Time Factors

BACKGROUNDSurgical treatment options for patients with cirrhosis and portal hypertension are complicated. In this study, we evaluated the effectiveness of a new treatment strategy, splenic auto-transplantation and oesophageal transection anastomosis. We report results from clinical observations, splenic immune function and portal dynamics in 274 patients.

METHODSFrom 1979 to 2005, 274 cirrhosis patients with portal hypertension underwent the new treatment strategy, and were followed up to compare results with those patients who underwent traditional surgical treatment. From 1999 to 2002, a randomized controlled trial (RCT) was performed on 40 patients to compare their post-operative immune function. From 1994 to 2006, another RCT enrolled 28 patients to compare portal dynamics using three-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D DEC MRA) investigation post operation.

RESULTSAmong 274 patients (mean age 41.8 years), the emergency operative mortality (4.4%), selective operative mortality (2.2%), complication rate (17.9%), prevalence of hepatic encephalopathy (< 1%), rate of portal hypertension gastritis (PHG) bleeding (9.1%), and morbidity of hepatic carcinoma (8%) were similar to those patients undergoing traditional operation; the spleen immunology function (Tuftsin, IgM) decreased in both groups 2 months post operation, but this decrease did not reach statistical significance. Through 3D DCE MRA, the cross sectional area and the velocity and volume of blood flow of the main portal vein decreased significantly after operation in both groups. The velocity and volume of blood flow in the auto-transplantation group was significantly lower than that in the control group.

CONCLUSIONSSplenic auto-transplantation and esophageal transection anastomosis is a safe, effective, and reasonable treatment strategy for patients with portal hypertension with varicial bleeding. It not only can correct hypersplenism, but may also achieve complete hemostasis. Spleens auto-transplanted into the retroperitoneal space can preserve immune function and establish broad collateral circulation.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anastomosis, Surgical ; Child ; Esophagus ; surgery ; Female ; Humans ; Hypertension, Portal ; immunology ; surgery ; Imaging, Three-Dimensional ; Immunoglobulin M ; blood ; Male ; Middle Aged ; Prospective Studies ; Spleen ; transplantation ; Transplantation, Autologous

BACKGROUNDThe myocardial ATP sensitive potassium channel (K(ATP) channel) has been known for more than two decades, the properties of this channel have been intensively investigated, especially the myocardial protection effect by opening this channel. Numerous studies, including hypothermic, using K(ATP) agonists to achieve a hyperpolarizing cardioplegic arrest, have shown a better myocardial protection than potassium arrest. However, there is no evidence showing that K(ATP) channel could be opened by its agonists under profound hypothermia. We investigated the effect of temperature on activation of myocardial K(ATP) channel by nicorandil.

METHODSIsolated ventricular myocytes were obtained by collagenase digestion of the hearts of guinea pigs and stored in KB solution at 4 degrees C. With a steady ground current, the myocytes were perfused with 1 mmol/L nicorandil until a steady IK(ATP) occurred. Then the cells were perfused with 1 mmol/L nicorandil plus 1 micromol/L glybenclamide. Currents signals were recorded on whole cells using patch clamp technique at several temperatures. The temperature of the bath solution around myocytes was monitored and was controlled at 4 degrees C, 10 degrees C, 20 degrees C, 25 degrees C and 35 degrees C respectively. About 10 cells were tested at each temperature, the cells were considered useful only when the outward current could be induced by nicorandil and blocked by glybenclamide. All data were analyzed using Graphpad PRISM 3.0 (Graphpad, San Diego, CA, USA). Nonlinear curve fitting was done in Clampfit (Axon) or Sigmaplot (SPSS).

RESULTSAt 4 degrees C, 10 degrees C, 20 degrees C, 25 degrees C and 35 degrees C, the time needed to open the myocardial K(ATP) channel was (81.0 +/- 0) minutes, (50.5 +/- 11.7) minutes, (28.8 +/- 2.3) minutes, (9.4 +/- 10.2) minutes and (2.3 +/- 1.0) minutes respectively (P = 0.003). The linear relationship between temperature and time needed to open the channel was y (min) = (4348.790 - 124.277x)/60, where y (min) is time needed to open K(ATP) channel, x is temperature, correlation coefficient r = -0.942 (P = 0.00), regression coefficient b = -124.277 (P = 0.00). The current densities among different temperatures were statistically different (P = 0.022), the current density was greater after the activation of K(ATP) channel at higher temperatures. The lower the temperature, the fewer cells in which K(ATP) channels could be opened. At 4 degrees C, only one cell in which the K(ATP) channel could be opened, took a quite long time (81 minutes) and the I-V curve was quite untypical.

CONCLUSIONSK(ATP) channel activated by nicorandil is temperature dependent and the temperature linearly related to time needed to open K(ATP) channel; the lower the temperature, the longer the time needed to open channel and the smaller the current density. At profound hypothermia, it is difficult to activate K(ATP) channels.

Adenosine Triphosphate ; pharmacology ; Animals ; Female ; Glyburide ; pharmacology ; Guinea Pigs ; Heart Ventricles ; Male ; Myocytes, Cardiac ; metabolism ; Nicorandil ; pharmacology ; Patch-Clamp Techniques ; Potassium Channels ; drug effects ; physiology ; Temperature

OBJECTIVETo evaluate the effect of titrated target-controlled infusion with propofol and remifentanil on anesthetics consumption and anesthesia depth in patients undergoing elective laparoscopic colorectal surgery.

METHODSSixty ASA I-III patients for elective laparoscopic colorectal surgery were enrolled. Titrated target-controlled infusion (TCI) with propofol and remifentanil was performed. Plasma concentration of the drugs was administered by titrated method to maintain bispectral index (BIS) in the range of 40-60 with systolic blood pressure (SBP) fluctuation within 20% of the basic value. BIS, SBP, plasma concentration of propofol and remifentanil were recorded at different time points. Awareness during operation was inquired postoperatively.

RESULTSDuring the entire anesthesia period, the blood pressure was stable and BIS was maintained less than 60. There was no awareness during operation. The plasma concentrations (95% confidence interval) for TCI of propofol and remifentanil were 2.55-2.65 mg/L and 4.09-4.26 μg/L respectively when existing surgical stimulation during anesthesia, and the plasma target concentration of propofol was lower than the recommended dosages.

CONCLUSIONTitrated target-controlled infusions with propofol and remifentanil for elective laparoscopic colorectal surgery can maintain proper anesthesia depth and reduce the drug consumption.

Adult ; Aged ; Aged, 80 and over ; Anesthesia, Intravenous ; methods ; Anesthetics, Intravenous ; administration & dosage ; Blood Pressure ; drug effects ; Colorectal Surgery ; Electroencephalography ; Female ; Humans ; Laparoscopy ; Male ; Middle Aged ; Piperidines ; administration & dosage ; Propofol ; administration & dosage