Anesthetics, Local ; chemistry ; pharmacology ; toxicity ; Central Nervous System ; drug effects ; Ethyl Chloride ; chemistry ; pharmacology ; toxicity ; Humans ; Inhalation ; Male ; Medical History Taking ; Neurologic Examination ; Patient Care Management ; methods ; Psychotropic Drugs ; chemistry ; pharmacology ; toxicity ; Substance-Related Disorders ; etiology ; physiopathology ; psychology ; therapy ; Treatment Outcome ; Volatilization ; Young Adult

OBJECTIVE: To evaluate the effect of dexmedetomidine combined with ropivacaine on brachial plexus block in patients scheduled for elective shoulder arthroscopy. METHODS: Ninety patients with American Society of Anesthesiologists (ASA) I or II, scheduled for elective shoulder arthroscopy, were randomly divided into three groups. In group R (n=30), the patients were given 10 mL of 0.375% ropivacaine in branchial plexus block (interscalene approach guided by ultrasound), in group D1 (n=30), the patients were given 10 mL of 0.375% ropivacaine (interscalene approach guided by ultrasound) + dexmedetomidine 0.2 μg/(kg×h) (intravenous pump infusion), and in group D2 (n=30), the patients were given 10 mL of 0.375% ropivacaine (interscalene approach guided by ultrasound) + dexedetomidine 0.7 μg/(kg×h) (intravenous pump infusion). To evaluate the effect of brachial plexus block before general anesthesia. Group D1 and group D2 were given dexmedetomidine intravenously for 1.0 μg/kg during 10 min, then the drug was pumped by 0.2 μg/(kg×h) and 0.7 μg/(kg×h) respectively until 30 min before the operation finished. Changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and before anesthesia (T0), 10 min (T1), 30 min (T2) after giving dexmedetomidine, discontinue medication (T3), after operation (T4), and extubation (T5) were investigated. Motor and sensory block onset times, block durations, and duration of analgesia were recorded. The scores of pain after operation and the adverse effects of shiver, hypopiesia, drowsiness, and blood loss were recorded during operation. RESULTS: Compared with group R, the duration of analgesia and duration of sensory block in group D1 and group D2 were significant longer (P<0.01), there was no significant difference between groups D1 and D2 (P>0.05). Compared with group R, at each time point of T1-T5, the heart rate and systolic blood pressure in group D1 and group D2 were significantly decreased (P<0.01). Compared with D1 group, the incidence of hypotension and bradycardia in group D2 were significantly different (P<0.05). CONCLUSION Intravenous dexmedetomidine could prolong the duration of analgesia time and sensory block within the brachial plexus block, inhibiting the stress response during arthroscopic shoulder surgery. Compared with high-dose, low-dose can provide safer and better clinical effect and reduce the adverse effects of dexmedetomidine.
Analgesics, Non-Narcotic ; Anesthetics, Local/therapeutic use* ; Arthroscopy ; Brachial Plexus ; Brachial Plexus Block ; Dexmedetomidine/therapeutic use* ; Double-Blind Method ; Humans ; Hypnotics and Sedatives/pharmacology* ; Prospective Studies ; Ropivacaine/therapeutic use* ; Shoulder Joint/surgery*

BACKGROUNDPreoperative incisional local anaesthesia with ropivacaine is a common method of providing post-laparoscopy pain relief. The pulmonary recruitment manoeuvre also provides pain relief, but the combined effect of these two methods on pain following laparoscopic procedures has not been reported. We investigated the efficacy of combining local anaesthetic infiltration of ropivacaine with pulmonary recruitment manoeuvre on postoperative pain following diagnostic hysteroscopy and laparoscopy.

METHODSThis prospective, randomized, controlled study involved 60 patients divided into two groups (n = 30, each). Group 1 received 20 ml of 0.5% ropivacaine injected peri-incisionally preoperatively, with intra-abdominal carbon dioxide removed by passive deflation. Group 2 received 20 ml of 0.5% ropivacaine injected peri-incisionally with five manual inflations of the lungs with a positive-pressure ventilation of 40 cmH2O at the end of surgery. The last inflation was held for 5 seconds. The intensity of postoperative incisional and shoulder pain was evaluated using a numerical rating scale at 0, 2, 4, 8, 12, 24 and 48 hours postoperatively by an independent blinded anaesthesiologist. Tramadol was given postoperatively for analgesia.

RESULTSCompared with group 1, incisional ropivacaine infiltration combined with pulmonary recruitment manoeuvre significantly reduced dynamic pain at 0 hour, 4 hours, and 24 hours postoperatively (4.1 ± 2.2 vs. 2.1 ± 1.9, P = 0.002; 2.7 ± 2.7 vs. 1.2 ± 1.3, P = 0.035; and 3.5 ± 2.1 vs. 2.1 ± 1.8, P = 0.03, respectively). Static incisional pain was significantly relieved at 0 hour, 2 hours, and 24 hours postoperatively (3.1 ± 1.7 vs. 1.6 ± 1.3, P = 0.001; 1.4 ± 1.3 vs. 0.5 ± 0.8, P = 0.012; and 2.3 ± 1.9 vs. 1.0 ± 1.5, P = 0.038, respectively). Group 2 had more patients without shoulder pain (P < 0.05) and fewer requiring tramadol (P < 0.05).

CONCLUSIONRopivacaine with pulmonary recruitment manoeuvre provided simple and effective pain relief after diagnostic hysteroscopy and laparoscopy.

Adolescent ; Adult ; Amides ; therapeutic use ; Anesthetics, Local ; pharmacology ; Female ; Humans ; Hysteroscopy ; methods ; Laparoscopy ; methods ; Middle Aged ; Pain, Postoperative ; drug therapy ; Positive-Pressure Respiration ; Shoulder Pain ; drug therapy ; Young Adult

OBJECTIVETo investigate the pharmacokinetics and pharmacodynamics of poly (lactide-co-glycolide) microspheres containing ropivacaine and dexamethasone for sciatic nerve block in mice.

METHODSA total of 165 female mice were randomly assigned into 3 groups, namely dexamethasone-loaded ropivacaine microsphere group (group A, n=55), ropivacaine microsphere group (group B, n=55) and PLGA microsphere group (group C, n=55). The mice received surgical implantation of the corresponding preparations near the sciatic nerve at the dose of 400 mg/kg. Hot plate test was used to evaluate the anesthetic effect of these microspheres at different time points after the implantation, and high-performance liquid chromatography (HPLC) was employed to determine plasma ropivacaine concentration.

RESULTSPharmacodynamic study showed that the duration of sciatic nerve sensory block was significantly longer in group A than in group B (P<0.05). The analysis of pharmacokinetics variables demonstrated that T(1/2) in group A was prolonged as compared with that of group B. No anesthetic effect was observed in group C.

CONCLUSIONDexamethasone-loaded ropivacaine microspheres can significantly prolong the analgesic effect of ropivacaine in mice.

Amides ; pharmacokinetics ; pharmacology ; Anesthetics, Local ; pharmacokinetics ; pharmacology ; Animals ; Delayed-Action Preparations ; Dexamethasone ; pharmacokinetics ; pharmacology ; Female ; Lactic Acid ; chemistry ; Mice ; Microspheres ; Nerve Block ; methods ; Polyglycolic Acid ; chemistry ; Random Allocation ; Sciatic Nerve

OBJECTIVE: To explore the alterations of serum of myelin basic protein (MBP) concentration in the plasma and ultrastructure in the spinal cord after continuous intrathecal injection of different ropivacaine concentrations in rats. METHODS: Ninety-six male Sprague-Dawley rats weighing 220 to approximately 280 g were randomly divided into a control group (Group N), Group R(1), R(2) and R(3) (24 rats in each group). Each group was subdivided into 4 subgroups (6 rats in each subgroup). According to the method of Yaksh's, a polyurethane microspinal catheter was inserted into the lumbar subarachnoid space in which 8 cm segment was left. Rats in each group were continuously received 40 microL of intrathecal injection of normal saline(Group N), 0.5%, 0.75%, and 1.0% ropivacaine (Group R(1),R(2),R(3)), 3 times every 1.5 hours. Blood (0.5 mL) was drawn from the femoral artery to determine serum concentrations of MBP at the detecting time T(0)(before inserted pipe)and T(1)(before the first intrathecal injection); for the subgroups, the examining time was at T(2), T(3), T(4) and T(5)(6, 12, 24 and 48 h respectively after the last time intrathecal administration). After blood was drawn, the rats in each subgroups were decapitated and the spinal cord of L(1-2) intumescentia lumbalis were immediately removed for electronic microscopic examination. RESULTS: MBP levels were comparatively steady in Group N, R(1) and R(2), while there was statistical difference between Group R(3) and Group N, R(1),R(2),and R(3) (P<0.05). MBP level of Group R(3) was significantly higher at T(2),T(3),T(4) and T(5) than that at T(0)(P<0.01). The ultrastructural changes of the spinal cord in Group R(3) were pycnosis of most neurons, dilation of most rough endoplasmic reticulum, and vague structure of mitochondria and endocytoplasmic reticulum. A few neurons were completely de-generated losing the normal structure, with vacuole degeneration of crista mitochondriales or even partial loss. CONCLUSION The spinal cord ultrastructure is selectively vulnerable after intrathecal 1.0% ropivacaine injection, which may be one of the important pathophysiological bases for local anesthetic neurotoxicity. MBP may serve as a sensitive and specific indicator of spinal cord damage after intra-thecal administration of ropivacaine.
Amides ; administration & dosage ; pharmacology ; Anesthetics, Local ; administration & dosage ; pharmacology ; Animals ; Injections, Spinal ; methods ; Male ; Myelin Basic Protein ; Nerve Tissue Proteins ; blood ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Ropivacaine ; Spinal Cord ; ultrastructure ; Transcription Factors ; blood

OBJECTIVETo compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness (LOC), effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index (BIS) were studied.

METHODSForty-five patients were divided into three groups to receive epidurally administered saline (Group S), 1.5% (w/w) lidocaine (Group L), or 0.5% (w/w) ropivacaine (Group R). Propofol infusion was started to produce blood concentration of 4 mug/ml. Once the BIS value reached 40~50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure (MABP), and heart rate (HR) at different study time points.

RESULTSDuring induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups.

CONCLUSIONEpidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.

Adult ; Amides ; pharmacology ; Anesthesia, Epidural ; Anesthesia, General ; Anesthetics, Local ; pharmacology ; Blood Pressure ; drug effects ; Electroencephalography ; Female ; Heart Rate ; drug effects ; Humans ; Lidocaine ; pharmacology ; Male ; Middle Aged ; Propofol ; pharmacology ; Time Factors

BACKGROUNDSpinal hyperbaric ropivacaine may produce more predictable and reliable anesthesia than plain ropivacaine for cesarean section. The dose-response relation for spinal hyperbaric ropivacaine is undetermined. This double-blind, randomized, dose-response study determined the ED50 (50% effective dose) and ED95 (95% effective dose) of spinal hyperbaric ropivacaine for cesarean section anesthesia.

METHODSSixty parturients undergoing elective cesarean section delivery with use of combined spinal-epidural anesthesia were enrolled in this study. An epidural catheter was placed at the L1 approximately L2 vertebral interspace, then lumbar puncture was performed at the L3 approximately L4 vertebral interspace, and parturients were randomized to receive spinal hyperbaric ropivacaine in doses of 10.5 mg, 12 mg, 13.5 mg, or 15 mg in equal volumes of 3 ml. Sensory levels (pinprick) were assessed every 2.5 min until a T7 level was achieved and motor changes were assessed by modified Bromage Score. A dose was considered effective if an upper sensory level to pin prick of T7 or above was achieved and no intraoperative epidural supplement was required. ED50 and ED95 were determined with use of a logistic regression model.

RESULTSED50 (95% confidence interval) of spinal hyperbaric ropivacaine was determined to be 10.37 (5.23 approximately 11.59) mg and ED95 (95% confidence interval) to be 15.39 (13.81approximately 23.59) mg. The maximum sensory block levels and the duration of motor block and the rate of hypotension, but not onset of anesthesia, were significantly related to the ropivacaine dose.

CONCLUSIONThe ED50 and ED95 of spinal hyperbaric ropivacaine for cesarean delivery under the conditions of this study were 10.37 mg and 15.39 mg, respectively. Ropivacaine is suitable for spinal anesthesia in cesarean delivery.

Adult ; Amides ; pharmacology ; Anesthesia, Obstetrical ; Anesthesia, Spinal ; Anesthetics, Local ; pharmacology ; Cesarean Section ; Dose-Response Relationship, Drug ; Double-Blind Method ; Female ; Humans ; Logistic Models ; Pregnancy

OBJECTIVETo study the effect of levobupivacaine and bupivacaine on the contractility of isolated uterine muscle strips from pregnant and non-pregnant female rats.

METHODSFull-thick myometrial strips were prepared from 18- to 21-day pregnant (n=8) and non-pregnant rats (n=7). After contractions became regular, strips were exposed to cumulative concentrations of the two drugs from 10(-8) to 10(-4) mol/L, amplitude and frequency of the uterine contraction was recorded.

RESULTSTwo local anesthetics caused a concentration dependent inhibition on contractility of myometrial strips from pregnant and non-pregnant rats. In the myometrium from non-pregnant rats, -logIC(50) of levobupivacaine and bupivacaine were 4.85 and 4.25 respectively. In the myometrium from pregnant rats, similar concentrations of levobupivacaine and bupivacaine were observed, -logIC(50) were 2.7 and 2.9 respectively. Levobupivacaine produced an increase in amplitude of contractions, while bupivacaine showed an increased trend in frequency.

CONCLUSIONThese results demonstrate that levobupivacaine and bupivacaine may inhibit myometrium contractility. The inhibitory effect of levobupivacaine or bupivacaine is not enhanced by gestation in rat. Levobupivacaine may have more positive influence than bupivacaine in pregnant myometrium.

Anesthetics, Local ; pharmacology ; Animals ; Bupivacaine ; analogs & derivatives ; blood ; pharmacology ; Dose-Response Relationship, Drug ; Female ; In Vitro Techniques ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Uterine Contraction ; drug effects

OBJECTIVETo investigate the effects of injecting Shenfu, an extract of traditional Chinese herbal medicines, on the central nervous system (CNS) and the cardiac toxicity of bupivacaine in rats.

METHODSSixteen male Sprague-Dawley rats, weighing form 280 to 320 g, were randomly assigned to two groups (n = 8 in each group). Animals in the control group received a saline injection 10 ml/kg while animals in the Shenfu group received an injection of Shenfu 10 ml/kg intraperitoneally 30 minutes before intravenous infusion of bupivacaine. Lead II of an electrocardiogram (EEG) was continuously monitored after 3 needles were inserted into the skin of both forelimbs and the left hind-leg of each rat. The femoral artery was cannulated for measurement of arterial blood pressure and blood sampling. The femoral vein was cannulated for the infusion of bupivacaine. After baseline measurement (arterial blood pressure, heart rate and arterial blood gas), 0.5% bupivacaine was infused intravenously at a rate of 2 mg.kg(-1).min(-1) to all animals until asystole occurred. The time of bupivacaine-induced convulsions, arrhythmia and asystole were determined. The dose of bupivacaine was then calculated at the corresponding time point.

RESULTSThe doses of bupivacaine that induced convulsions, arrhythmia and cardiac arrest were remarkably larger in Shenfu injection-treated animals than in saline-treated rats [convulsions, (10.5 +/- 1.9) mg/kg vs (7.2 +/- 1.5) mg/kg; arrhythmia (10.5 +/- 2.0) mg/kg vs (7.2 +/- 1.9) mg/kg; asystole, (32.8 +/- 8.5) mg/kg vs (25.0 +/- 5.0) mg/kg; P = 0.006, 0.009 and 0.044, respectively].

CONCLUSIONThe Shenfu injection is able to reduce the toxicity of bupivacaine to CNS and cardiac system in rats.

Anesthetics, Local ; toxicity ; Animals ; Bupivacaine ; toxicity ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Electrocardiography ; drug effects ; Heart Rate ; drug effects ; Injections, Intraperitoneal ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley

AIMTo study the cutaneous permeation kinetics and pharmacodynamics of lidocaine gel.

METHODSThe concentration of lidocaine in dermis following topical application in rats was determined by the cutaneous microdialysis technique and related parameters were calculated; the pharmacodynamics of the gel was evaluated by electric stimulation method with EMLA (eutectic mixture of local anesthetics) cream as a control.

RESULTSThe peak of percutaneous absorption kinetic profile of lidocaine gel across rat skin occurred at 1.25 h; the onset time of local anesthetic action of lidociane gel was similar to that of EMLA, but both the duration and depth of anesthetic effect were superior to EMLA cream.

CONCLUSIONLidocaine gel showed good anesthetic effect. The minimum effective concentration of lidocaine in dermis is 12 mg.L-1.

Anesthesia, Local ; Anesthetics, Local ; pharmacokinetics ; pharmacology ; Animals ; Gels ; Lidocaine ; pharmacokinetics ; pharmacology ; Male ; Pain Threshold ; drug effects ; Prilocaine ; pharmacokinetics ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Skin Absorption