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Purpose: To evaluate the effects of levobupivacaine on neuromuscular transmission and neuromuscular blockade produced by pancuronium in vitro., Methods: Thirty rats were distributed into groups (n = 5) according to the drug used alone or in combination: Group I - levobupivacaine (5 µg.mL-1); Group II - pancuronium (2 µg.mL-1); Group III - pancuronium (2 µg.mL-1) + levobupivacaine (5µg.mL-1). The following parameters were evaluated: 1) amplitude of diaphragmatic response to indirect stimulation, before and 60 minutes after the addition of levobupivacaine and pancuronium alone, and after the addition of levobupivacaine combined with pancuronium; 2) membrane potentials (MP) and miniature endplate potentials (MEPP)., Results: Levobupivacaine alone did not alter the amplitude of muscle response and MP. In preparations previoulsy exposed to levobupivacaine, the block with pancuronium was significantly denser (90.2 ± 15.2%), showing a significant difference (p=0.031) in comparison to the block produced by pancuronium alone (48.9% ± 9.8%). There was a decrease in the frequency and amplitude of MEPPs., Conclusion: Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.

Background and Aims: Local anaesthetics are drugs that are widely used in clinical practice. However, the effects of these drugs on the neuromuscular junction and their influence on the blockade produced by non-depolarising neuromuscular blocking drugs are still under investigation. The aim of this study was to evaluate, in vitro, the influence of a 50% enantiomeric excess bupivacaine mixture on neuromuscular transmission and neuromuscular block produced by pancuronium., Methods: Rats were distributed into three groups (n = 5) according to the drug studied namely, 50% enantiomeric excess bupivacaine mixture (5 μg/mL); pancuronium (2 μg/mL); 50% enantiomeric excess bupivacaine mixture + pancuronium. The following parameters were evaluated: (1) Effects of a 50% enantiomeric excess bupivacaine mixture on membrane potential (MP) and miniature endplate potentials (MEPPs); (2) amplitude of diaphragmatic response before and 60 min after the addition of a 50% enantiomeric excess bupivacaine mixture; the degree of neuromuscular block with pancuronium and pancuronium combined with a 50% enantiomeric excess bupivacaine mixture., Results: A 50% enantiomeric excess bupivacaine mixture did not alter the amplitude of muscle response (MP) but decreased the frequency and amplitude of MEPP. The block produced by pancuronium was potentiated by a 50% enantiomeric excess bupivacaine mixture., Conclusion: A 50% enantiomeric excess bupivacaine mixture used alone did not affect neuromuscular transmission, but potentiated the neuromuscular block produced by pancuronium. No action was shown on the muscle fibre, and alterations on MEPPs demonstrated a presynaptic action.

Background and Objectives: The local anesthetic effects on neuromuscular junction and its influence on blockade produced by nondepolarizing neuromuscular blockers are still under-investigated; however, this interaction has been described in experimental studies and in humans. The aim of this study was to evaluate in vitro the interaction between ropivacaine and pancuronium, the influence on transmission and neuromuscular blockade, and the effectiveness of neostigmine and 4-aminopyridine to reverse the blockade., Methods: Rats were divided into groups (n=5) according to the study drug: ropivacaine (5μgmL(-1)); pancuronium (2μg.mL(-1)); ropivacaine+pancuronium. Neostigmine and 4-aminopyridine were used at concentrations of 2μgmL(-1) and 20μgmL(-1), respectively. The effects of ropivacaine on membrane potential and miniature end-plate potential, the amplitude of diaphragm responses before and 60minutes after the addition of ropivacaine (degree of neuromuscular blockade with pancuronium and with the association of pancuronium-ropivacaine), and the effectiveness of neostigmine and 4-aminopyridine on neuromuscular block reversal were evaluated., Results: Ropivacaine did not alter the amplitude of muscle response (the membrane potential), but decreased the frequency and amplitude of the miniature end-plate potential. Pancuronium blockade was potentiated by ropivacaine, and partially and fully reversed by neostigmine and 4-aminopyridine, respectively., Conclusions: Ropivacaine increased the neuromuscular block produced by pancuronium. The complete antagonism with 4-aminopyridine suggests presynaptic action of ropivacaine., (Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.)

Purpose: To evaluate the efficacy and side-effects of fentanyl and sufentanil combined with hyperbaric spinal bupivacaine in elective cesarean section., Methods: A prospective, randomized, double-blind study with 64 term parturients, distributed into 2 groups according to the opioid combined with hyperbaric bupivacaine 0.5% (10mg): GF - fentanyl (25 µg) and GS - sufentanil (5.0 µg). The latency and maximum sensory block level; degree and duration of motor block; duration and quality of analgesia; maternal-fetal repercussions were evaluated. This was an intention-to-treat analysis with a 5% significance level., Results: The latency period, maximum sensory block level, motor block degree and perioperative analgesia were similar in both groups. Motor block and analgesia had a longer duration in the sufentanil group. Maternal adverse effects and neonatal repercussions were similar. The incidence of hypotension was higher in the fentanyl group. In both groups, there was a predominance of patients who were awake and either calm or sleepy., Conclusions: The addition of fentanyl and sufentanil to hyperbaric subarachnoid bupivacaine was shown to be effective for the performance of cesarean section, and safe for the mother and fetus. Analgesia was more prolonged with sufentanil.

Purpose: To assess the probable actions of ropivacaine, 50% enantiomeric excess bupivacaine mixture (S75-R25) and levobupivacaine on neuromuscular transmission in vitro., Methods: Thirty rats were distributed into groups (n=5) according to the drug used: ropivacaine, bupivacaine (S75-R25) and levobupivacaine. The concentration used for the three local anesthetics (LA) was 5 µg.mL. (-1)The following parameters were evaluated: 1) LA effects on membrane potential (MP) and miniature end plate potential (MEPP). A chick biventer cervicis preparation was also used to evaluate LA effects on the contracture response to acetylcholine., Results: LA did not alter MP values and decreased the frequency and amplitude of MEPP. In a chick biventer cervicis preparation, bupivacaine (S75-R25) and levobupivacaine decreased the contracture response to acetylcholine with statistical significance, in comparison to ropivacaine., Conclusions: In the concentrations used, levobupivacaine and bupivacaine (S75-R25) exhibited presynaptic and postsynaptic actions evidenced by alterations in miniature end plate potentials and contracture response to acetylcholine. Ropivacaine only had a presynaptic action.

Objective: To describe anesthesia for renal transplantation that progressed to a sharp potassium increase after kidney reperfusion with Euro-Collins' solution in the operative field. We will also report on diagnosis and treatment used., Conclusion: The use of infusion solutions in the surgical field requires careful monitoring, such as electrocardiography, measurement of serum potassium, and availability of calcium gluconate, insulin, and albuterol for immediate use. The replacement of Euro-Collins' solution for saline solution immediately before the implant may be a useful option in patients with high levels of potassium.

Background and Objective: Different drugs, including hypnotics, may influence the pharmacodynamic effects of neuromuscular blockers (NMB). The aim of this study was to evaluate the influence of propofol and etomidate on cisatracurium-induced neuromuscular blockade., Method: We included 60 patients, ASA I and II, undergoing elective surgery under general anesthesia in the study and randomly allocated them into two groups, according to their hypnotic drug: GI (propofol) and GII (etomidate). Patients received intramuscular (IM) midazolam (0.1mg.kg(-1)) as premedication and we performed induction with propofol (2.5mg.kg(-1)) or etomidate (0.3mg.kg(1)), preceded by fentanyl (250mg) and followed by cisatracurium (0.1mg.kg(-1)). The patients were ventilated with 100% oxygen until obtaining a reduction of 95% or more in the adductor pollicis response amplitude, with subsequent laryngoscopy and tracheal intubation. Neuromuscular function was monitored by acceleromyograhpy. We evaluated the onset of action of cisatracurium, tracheal intubation conditions, and hemodynamic repercussions., Results: The mean time and standard deviations of cisatracurium onset were: GI (86.6±14.3s) and GII (116.9±11.6s), with a significant difference (p<0, 0001). Intubation conditions were acceptable in 100% of GI and 53.3% of GII patients (p<0.0001)., Conclusion: Induction of neuromuscular blockade with cisatracurium was faster, with better intubation conditions in patients receiving propofol compared to those receiving etomidate, without hemodynamic repercussions., (Copyright © 2013 Elsevier Editora Ltda. All rights reserved.)

Purpose: To investigate the anti-inflammatory effects of simvastatin in rats undergoing one-lung ventilation (OLV) followed by lung re-expansion., Methods: Male Wistar rats (n=30) were submitted to 1-h OLV followed by 1-h lung re-expansion. Treated group received simvastatin (40 mg/kg for 21 days) previous to OLV protocol. Control group received no treatment or surgical/ventilation interventions. Measurements of pulmonary myeloperoxidase (MPO) activity, pulmonary protein extravasation, and serum levels of cytokines and C-reactive protein (CRP) were performed., Results: OLV significantly increased the MPO activity in the collapsed and continuously ventilated lungs (31% and 52% increase, respectively) compared with control (p<0.05). Treatment with simvastatin significantly reduced the MPO activity in the continuously ventilated lung but had no effect on lung edema after OLV. The serum IL-6 and CRP levels were markedly higher in OLV group, but simvastatin treatment failed to affect the production of these inflammatory markers. Serum levels of IL-1β, TNF-α and IL-10 remained below the detection limit in all groups., Conclusions: In an experimental one-lung ventilation model pre-operative treatment with simvastatin reduces remote neutrophil infiltration in the continuously ventilated lung. Our findings suggest that simvastatin may be of therapeutic value in OLV-induced pulmonary inflammation deserving clinical investigations.

Purpose: To comparatively study the efficacy and maternal and fetal side-effects of two doses of bupivacaine associated with morphine and clonidine, administered by the subarachnoid route for cesarean section., Methods: The study included 66 pregnant women at term, distributed into two groups. GI: bupivacaine 8.0 mg (1.6 mL) + clonidine 75 µg (0.5 mL) + morphine 100 µg (1.0 mL) and GII: bupivacaine 10 mg (2.0 mL) + clonidine 75 µg (0.5 mL) + morphine 100 µg (1.0 mL). The following parameters were assessed: onset and maximum level of sensory block; quality of intraoperative and postoperative analgesia; degree and duration of motor block; maternal repercussions and Apgar score., Results: The onset of sensory block, quality of intraoperative analgesia and total duration of analgesia were similar in both groups; maximum extent of sensory block predominated in T4; maximum degree of motor block (Bromage 3); time motor block regression was significantly longer in GII; Hemodynamic, respiratory repercussions, adverse maternal effects and Apgar scores were similar between groups. In both groups, there was a predominance of drowsy or sleeping patients., Conclusion: The addition of morphine and clonidine to low doses of hyperbaric bupivacaine produced adequate anesthesia for cesarean section and good postoperative analgesia, without any maternal and fetal repercussions.

Purpose: To describe the maternal complications due to therapeutic endoscopic procedures in fetal Medicine performed at an university center in Brazil., Methods: Retrospective observational study including patients treated from April 2007 to May 2010 who underwent laser ablation of placental vessels (LAPV) for severe twin-twin transfusion syndrome (TTTS); fetal tracheal occlusion (FETO) and endoscopic removal of tracheal balloon in cases of severe congenital diaphragmatic hernia (CDH); LAPV with or without bipolar coagulation of the umbilical cord in cases of twin reversed arterial perfusion (TRAP) sequence. The main variables described for each disease/type of surgery were maternal complications and neonatal survival (discharge from nursery)., Results: Fifty-six patients underwent 70 procedures: Severe TTTS (34 patients; 34 surgeries); severe CDH (16 patients; 30 surgeries), and TRAP sequence (6 patients; 6 surgeries). Among 34 women who underwent LAPV for TTTS, two (2/34=5.9%) experienced amniotic fluid leakage to the peritoneal cavity and seven (7/34=20.6%) miscarried after the procedure. Survival of at least one twin was 64.7% (22/34). Among 30 interventions performed in cases of CDH, there was amniotic fluid leakage into the maternal peritoneal cavity in one patient (1/30=3.3%) and premature preterm rupture of membranes after three (3/30=30%) fetoscopies for removal of the tracheal balloon. Infant survival with discharge from nursery was 43.8% (7/16). Among six cases of TRAP sequence, there was bleeding into the peritoneal cavity after surgery in one patient (1/6=16.7%) and neonatal survival with discharge from nursery was 50% (3/6)., Conclusions: In agreement with the available data in literature, at our center, the benefits related to therapeutic endoscopic interventions for TTTS, CDH and TRAP sequence seem to overcome the risks of maternal complications, which were rarely considered severe.

Purpose: To describe the results of laser ablation of placental vessels for the treatment of severe twin-to-twin transfusion syndrome in an university center in Brazil., Methods: Retrospective observational study of patients treated at UNICAMP from 2007 to 2009. Laser ablation of placental vessels was performed in cases of severe twin-twin transfusion syndrome (Quintero stages II, III and IV) diagnosed before 26 complete weeks of gestation. The main variables evaluated in this series were gestational age at delivery, survival (discharge from the nursery) of at least one twin and neurological damage in survivors. Logistic regression was used to investigate the influence of cervical length, gestational age and stage of the disease (before the surgery) on the occurrence of delivery/abortion and fetal death after the intervention, and the influence on severe preterm birth and survival., Results: In the whole series, at least one twin survived in 63.3% of cases (19/30). Among patients who did not have delivery/abortion after surgery, the survival of at least one twin was 82.6% (19/23). In this subgroup (n=23), mean gestational age in delivery was 31.9 weeks and neurological damage was identified in one neonate (1/31; 3.2%). Cervix length influenced the occurrence of delivery/abortion after surgery (p-value=0.008). Among seven patients (7/30; 23.3%) who carried this complication, five (5/7; 71.4%) had cervix length lower than 15 mm. Among the 23 patients who did not have delivery/abortion as a result of the surgery, the highest stages of the disease (III and IV) increased the risk of delivery prior to 32 complete weeks of gestation (p-value=0.025) and decreased the chance of survival of both twins (p-value=0.026)., Conclusions: The results are similar to those available in the literature. In our series, the main factors associated with poorer results were short cervix (lower than 15 mm) and the highest stages of the disease (III and IV) at the time of the treatment.

Background and Objectives: Several factors affect the cephalad dispersion of the anesthetic solution in the subarachnoid space; among them, physiological changes of pregnancy and the dose and volume of the local anesthetics should be mentioned. The objective of this study was to assess the effectivity and side effects of different volumes of the subarachnoid administration of the association of hyperbaric bupivacaine and sufentanil in cesarean sections., Methods: Forty patients, ASA I and II, undergoing elective cesarean section under spinal block were divided in two groups, according to the volume of the anesthetic solution: Group I (4 mL) and Group II (3 mL). The association of hyperbaric bupivacaine (10 mg(2) mL) and sufentanil (5 microg-1 mL) was used in both groups. In Group I, 1 mL of NS was added to the solution to achieve the volume of 4 mL. The following parameters were evaluated: latency of the blockade; upper limit of the sensorial blockade; degree of motor blockade; time for regression of the motor blockade; total duration of analgesia; maternal side effects; and neonatal repercussions., Results: Latency, the upper limit of the sensorial blockade, and the degree and time for regression of the motor blockade were similar in both groups; duration of analgesia was greater in Group I than in Group II, which was statistically significant. The incidence of side effects was similar in both groups. Maternal cardiocirculatory changes and neonatal repercussions were not observed., Conclusions: Four milliliter of anesthetic solution composed of hyperbaric bupivacaine, 10 mg, associated with 5 microg of sufentanil was more effective than 3 ml of the same solution, providing better intra-and postoperative analgesia without maternal-fetal repercussions.

Background and Objectives: The effects of local anesthetics (LA) on neuromuscular transmission and their influence on the neuromuscular blockade produced by competitive neuromuscular blockers have not been fully investigated. The objective of this study was to evaluate, in vitro, the effects of lidocaine and 50% enantiomeric excess bupivacaine (S75-R25) on the neuromuscular blockade produced by rocuronium., Methods: The rats were divided in five groups (n = 5) according to the drug used: isolated lidocaine, bupivacaine (S75-R25), or rocuronium (groups I, II, and II); and rocuronium in preparations previously exposed to LAs (groups IV and V). The concentrations used were as follows: 20 microg x mL(-1), 5 microg x mL(-1), and 4 microg x mL(-1) of lidocaine, bupivacaine (S75-R25), and rocuronium, respectively. The following parameters were evaluated: 1) the strength of muscular contraction of the diaphragm to indirect electrical stimulations, before and 60 minutes after the isolated addition of the LAs and rocuronium, and the association AL-rocuronium; and 2) the effects of LAs on membrane potential (MP) and miniature end-plate potentials (MEPP). The effect of LAs on muscle contraction in response to acetylcholine was evaluated in chick biventer cervicis preparations., Results: Isolated lidocaine and bupivacaine (S75-R25) did not change the muscular response and the levels of MPs. In preparations exposed to LAs, rocuroniuminduced blockade was significantly greater than that produced by rocuronium alone. In chick biventer cervicis preparations, lidocaine and bupivacaine (S75R25) decreased contraction in response to acetylcholine. Lidocaine increased the frequency of MEPPs, which was followed by the blockade; bupivacaine (S75R25) caused a reduction in MEPPs followed by blockade., Conclusions: Local anesthetics caused a potentiation of the neuromuscular blockade produced by rocuronium. The results showed pre- and post-synaptic effects.

Background and Objectives: Epidural 0.5% racemic bupivacaine associated with opioids is a technique used in cesarean sections; however, its toxicity has been questioned. 50% Enantiomeric excess bupivacaine has lower cardio- and neurotoxicity. The efficacy of epidural 0.5% racemic bupivacaine and 0.5% enantiomeric excess bupivacaine associated with sufentanil in parturients undergoing cesarean sections was evaluated., Methods: Fifty gravida at term, undergoing elective cesarean section under epidural block, were divided in two groups according to the local anesthetic used: Group I - 0.5% racemic bupivacaine with vasoconstrictor; and Group II - 0.5% enantiomeric excess bupivacaine (S75-R25) with vasoconstrictor. In both groups, the local anesthetic (100 mg) was associated with sufentanil (20 microg), and a total of 24 mL of the solution was used. The following parameters were evaluated: latency of the sensitive blockade; maximal level of the sensitive blockade; degree for motor blockade; time of motor blockade regression; duration of analgesia; maternal side effects; and neonatal repercussions., Results: Latency, maximal level of sensitive blockade, degree of motor blockade, and duration of analgesia were similar in both groups; the mean time for regression of the motor blockade was significantly smaller in Group II. The incidence of side effects was similar in both groups. Maternal cardiocirculatory changes and neonatal repercussions were not observed., Conclusions: Epidural racemic bupivacaine and 50% enantiomeric excess bupivacaine provided adequate anesthesia for cesarean sections. 50% Enantiomeric excess bupivacaine is a promising alternative for this procedure, since it has faster regression of the motor blockade, which is desirable in obstetric patients.

Purpose: To evaluate in vitro lidocaine and racemic bupivacaine effects in neuromuscular transmission and in neuromuscular blockade produced by rocuronium., Methods: Rats were distributed in 5 groups (n = 5) in agreement with the studied drugs: lidocaine, racemic bupivacaine, rocuronium, separately (Groups I, II, III); rocuronium in preparations exposed to local anesthetics (Groups IV, V). The concentrations used were: 20 microg/mL, 5 microg/mL and 4 microg/mL, for lidocaine, bupivacaine and rocuronium, respectively. It was evaluated: 1) amplitude of diaphragm muscle response to indirect stimulation, before and 60 minutes after separately addition of lidocaine, racemic bupivacaine and rocuronium and the association of local anesthetics - rocuronium; 2) membrane potentials (MP) and miniature end-plate potentials (MEPP)., Results: Lidocaine and bupivacaine separately didn't alter the amplitude of muscle response and MP. In preparations previously exposed to lidocaine and racemic bupivacaine, the rocuronium blockade was significantly larger (90.10 +/- 9.15% and 100%, respectively), in relation to the produced by rocuronium separately (73.12 +/- 9.89%). Lidocaine caused an increase in the frequency of MEPP, being followed by blockade; racemic bupivacaine produced decrease being followed by blockade., Conclusions: Local anesthetics potentiated the blockade caused by rocuronium. The alterations of MEPP identify presynaptic action.

Background and Objectives: Latex allergy is becoming increasingly more frequent, affecting patients and health care professionals. The objective of this report was to present the case of a child with allergy to latex, who developed anaphylaxis during anesthesia for renal transplantation, and emphasize some of the multidisciplinary conducts used to decrease the risk of anaphylactic shock after graft reperfusion., Case Report: A male child, 5 years and 10 months old, P3 by the ASA classification, with a history of allergy to latex diagnosed after contact with balloons and confirmed by Rast test specific for latex and Prick test, underwent renal transplantation of a live donor graft for end-stage renal disease secondary to urologic malformation. The protocols for patients with Latex Allergy adopted by the Anesthesiology and Nursing Departments of the Hospital das Clínicas da UNICAMP were observed to avoid exposure of the child to latex. They started the day before the surgery by cleaning the operating rooms and substituting of all medical-hospital products by latex-free material. The equipment and materials used during the procedure were latex-free according to a technical report provided by the manufacturers. The surgery was done under general anesthesia and controlled mechanical ventilation. At the end of the surgery, the patient required blood transfusion, which was administered by a pressurizer; he developed cutaneous rash and the blood transfusion was discontinued, hydrocortisone was administered, and the infusion of crystalloids was increased. The child had an immediate and satisfactory response to the treatment., Conclusions: Latex allergy has become a public health problem and the knowledge of specific therapeutic conducts allows immediate treatment and decreases patient risks.

This study reports an investigation of the pharmacological activity, cytotoxicity and local effects of a liposomal formulation of the novel local anaesthetic ropivacaine (RVC) compared with its plain solution. RVC was encapsulated into large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine, cholesterol and alpha-tocopherol (4:3:0.07, mole %). Particle size, partition coefficient determination and in-vitro release studies were used to characterize the encapsulation process. Cytotoxicity was evaluated by the tetrazolium reduction test using sciatic nerve Schwann cells in culture. Local anaesthetic activity was assessed by mouse sciatic and rat infraorbital nerve blockades. Histological analysis was performed to verify the myotoxic effects evoked by RVC formulations. Plain (RVC(PLAIN)) and liposomal RVC (RVC(LUV)) samples were tested at 0.125%, 0.25% and 0.5% concentrations. Vesicle size distribution showed liposomal populations of 370 and 130 nm (85 and 15%, respectively), without changes after RVC encapsulation. The partition coefficient value was 132 +/- 26 and in-vitro release assays revealed a decrease in RVC release rate (1.5 fold, P < 0.001) from liposomes. RVC(LUV) presented reduced cytotoxicity (P < 0.001) when compared with RVC(PLAIN). Treatment with RVC(LUV) increased the duration (P < 0.001) and intensity of the analgesic effects either on sciatic nerve blockade (1.4-1.6 fold) and infraorbital nerve blockade tests (1.5 fold), in relation to RVC(PLAIN). Regarding histological analysis, no morphological tissue changes were detected in the area of injection and sparse inflammatory cells were observed in only one of the animals treated with RVC(PLAIN) or RVC(luv) at 0.5%. Despite the differences between these preclinical studies and clinical conditions, we suggest RVC(LUV) as a potential new formulation, since RVC is a new and safe local anaesthetic agent.

Background and Objectives: Pipecuronium is a non-depolarizing neuromuscular blocker with similar properties to pancuronium, but without cardiovascular effects. Neuromuscular effects, conditions of tracheal intubation, and hemodynamic repercussions of two different doses of pipecuronium were evaluated., Method: Patients were divided into two groups according to the dose of pipecuronium: Group I (0.04 mg x kg(-1)) and Group II (0.05 mg x kg(-1)). Intramuscular midazolam (0.1 mg x kg(-1)) was administered 30 minutes before the surgery. Propofol (2.5 mg x kg(-1)), preceded by fentanyl (5 microg x kg(-1)) and pipecuronium (0.04 and 0.05 mg x kg(-1) for Groups I and II, respectively), was administered for anesthetic induction. Patients were ventilated with 100% oxygen via a face mask until a 75% reduction in the amplitude of the response to an isolated stimulus (1 Hz) is achieved, at which time laryngoscopy and intubation were carried out. Anesthetic maintenance was achieved with isoflurane (0.5 to 1%) with a mixture of 50% O2 and N2O. Mechanical ventilation was used to maintain P(ET)CO2 between 32 and 36 mmHg. The pharmacodynamics of pipecuronium was evaluated by acceleromyography., Results: Mean times and standard deviation for the onset of action, clinical duration (T1(25%)), and recovery index (T1(25-75%)) were: Group I (122.10 +/- 4.18 sec, 49.63 +/- 9.54 min, and 48.21 +/- 6.72 min), and Group II (95.78 +/- 8.91 sec, 64.84 +/- 13.13 min, and 48.52 +/- 4.95 min). Onset of action, clinical duration, and conditions of tracheal intubation were significantly different for both groups., Conclusions: Pipecuronium at a dose of 0.05 mg x kg(-1) can be used in prolonged procedures in which cardiovascular changes should be avoided.

Purpose: To evaluate in vitro and in vivo neuromuscular blockade produced by rocuronium in rats treated with Phenobarbital and to determine cytochrome P450 and cytochrome b5 concentrations in hepatic microsomes., Methods: Thirty rats were included in the study and distributed into 6 groups of 5 animals each. Rats were treated for seven days with phenobarbital (20 mg/kg) and the following parameters were evaluated: 1) the amplitude of muscle response in the preparation of rats exposed to phenobarbital; 2) rocuronium effect on rat preparation exposed or not to phenobarbital; 3) concentrations of cytochrome P450 and cytochrome b5 in hepatic microsomes isolated from rats exposed or not to phenobarbital. The concentration and dose of rocuronium used in vitro and in vivo experiments were 4 microg/mL and 0,6 mg/kg, respectively., Results: Phenobarbital in vitro and in vivo did not alter the amplitude of muscle response. The neuromuscular blockade in vitro produced by rocuronium was significantly different (p=0.019) between exposed (20%) and not exposed (60%) rats; the blockade in vivo was significantly greater (p=0.0081) in treated rats (93.4%). The enzymatic concentrations were significantly greater in rats exposed to phenobarbital., Conclusions: Phenobarbital alone did not compromise neuromuscular transmission. It produced enzymatic induction, and neuromuscular blockade in vivo produced by rocuronium was potentiated by phenobarbital.

Background and Objectives: This experimental study investigated the in vitro and in vivo neuromuscular blockade of rocuronium and atracurium in rats treated with carbamazepine and determined the concentration of cytochrome P450 and b5 reductase in hepatic microsomes., Methods: Rats were treated with carbamazepine (CBZ)--40 mg x kg(-1) by gavage and sacrificed on the eighth day under anesthesia with urethane. In vitro and in vivo preparations followed the techniques of Bulbring and Leeuwin and Wolters, respectively. Concentrations and doses of the neuromuscular blockers used in in vitro and in vivo preparations were, respectively, 20 microg x mL(-1) and 0.5 mg x kg(-1) for atracurium (ATC); and 4 microg x kg(-1) and 0.6 mg x kg(-1) for rocuronium (ROC). Each protocol had an n = 5 and the response was observed for 60 minutes. The effects of ATC and ROC were evaluated in the preparations of rats treated with carbamazepine (CBZ(t)) and compared to those of non-treated rats (CBZ(st)). The concentration of cytochrome P450 and b5 reductase were determined in hepatic chromosomes of rats treated with carbamazepine (CBZ(t)) and non-treated rats (CBZ(st))., Results: Carbamazepine did not change the amplitude of neuromuscular response; differences in the neuromuscular blockade produced by atracurium in CBZ1 preparations were not observed, in vitro or in vivo, when compared with CBZ(st); the neuromuscular blockade produced by rocuronium in CBZ(t) preparations was potentiated in vitro. Carbamazepine did not change the concentrations of cytochrome P450 and b5., Conclusions: Seven-day treatment with carbamazepine did not change the neuromuscular blockade produce by atracurium, but altered the in vitro effects of rocuronium. The duration of the treatment was not enough to cause enzymatic induction and decrease the sensitivity to rocuronium.

Purpose: To evaluate the influence of two stimulation frequencies on the installation of neuromuscular blockade produced by pancuronium and rocuronium on the rat diaphragm., Methods: Diaphragms were submitted to an indirect frequency stimulation of 0.1 and 1 Hz (Groups I and II, respectively). Subgroups were formed (n=5) according to the neuromuscular blocker employed (pancuronium-2 microg/ml and rocuronium-4 microg/ml). The twitch height depression was evaluated at 5, 15 and 30 minutes after adding the neuromuscular blocker., Results: The decrease in twitch height was greater (p<0.01) with a frequency of 1 Hz at all time periods studied both in preparations that are blocked with pancuronium and in those that are blocked with rocuronium., Conclusion: The frequency of stimulation interferes significantly with the installation of neuromuscular blockade produced by pancuronium and rocuronium, since the reduction in amplitude of the rat diaphragm response was greater for 1 Hz frequencies, at all periods studied.

Background and Objectives: Lithium is widely used for the treatment of bipolar disorders and can interact with neuromuscular blockers. There is a controversy about the mechanisms by which it affects neuromuscular transmission and its interaction with neuromuscular blockers. The objective of this study was to evaluate, on the rat diaphragm, the effects of lithium on the muscular response and indirect stimulation, and the possible interaction with neuromuscular blockers., Methods: Rats weighing between 250 and 300 g were sacrificed under urethane anesthesia. The phrenic nerve-diaphragm preparation was assembled according to the Bulbring technique. The diaphragm was kept under tension, connected to an isometric transducer, and submitted to indirect stimulation with a frequency of 0.1 Hz. The contractions of the diaphragm were registered on a physiograph. The analysis of the amplitude of the muscular responses evaluated: the effects of the isolated drugs: lithium (1.5 mg.mL-1); atracurium (20 microg.mL-1), and cisatracurium (3 microg.mL-1); the lithium-neuromuscular blockers association; and the effects of lithium on the neuromuscular blockade produced by atracurium (35 microg.mL-1) and cisatracurium (5 microg.mL-1). The effects were evaluated before and 45 minutes after the addition of the drugs. The effects of lithium on membrane potentials (MP) and miniature end-plate potentials (MEPP) were also evaluated., Results: Lithium by itself did not change the amplitude of the muscular responses, but it decreased significantly the neuromuscular blockade produced by atracurium and cisatracurium. It did not change MP and caused an initial increase in MEPP., Conclusions: Lithium by itself did not compromise neuromuscular transmission and increased the resistance to the effects of atracurium and cisatracurium. It did not show any action on the muscle fiber, and the changes in miniature end-plate potentials indicated pre-synaptic action.

Background and Objectives: It has already been proved that procainamide potentiates the neuromuscular blockade of d-tubocurarine; however, the mechanism of this potentiation is controversial. The aim of this study was to assess the influence of procainamide on the neuromuscular blockade produced by rocuronium and investigate the mechanisms of this interaction., Methods: Fifteen rats (250 to 300 g) were used in the preparation described by Bülbring. They were divided in three groups (n = 5 each): procainamide - 20 microg mL(-1) (Group I); rocuronium - 4 microg mL(-1) (Group II); and rocuronium - 4 microg mL(-1) and procainamide - 20 microg mL(-1) (Group III). The following parameters were evaluated: 1) amplitude of muscle contractions under indirect stimulation, before and after the administration of the drugs; 2) miniature end plate potentials (MEPPs); and 3) the efficacy of 4-aminopyridine in reverting the muscular blockade. The mechanism of the interaction was studied in Biventer cervicis (n = 5) and in the denervated rat diaphragm (n = 5), observing the influence of procainamide in the response to acetylcholine., Results: Procainamide alone did not change the neuromuscular responses. Group III presented a 68.6% +/- 7.1% blockade, which represented a statistically significant difference (p = 0.0067) when compared with Group II (10.4% +/- 4.5%), which was reverted by 4-aminopiridine. Procainamide increased the frequency of the MEPP, followed by a blockade that was reverted by 4-aminopiridine. In Biventer cervicis, procainamide increased the contraction in response to acetylcholine, which was not observed in the denervated diaphragm., Conclusions: Procainamide potentiated the blockade caused by rocuronium. The changes observed with MEPP and Biventer cervicis identified pre-synaptic action. The antagonism of 4-aminopiridine on the blockade of the MEPP suggested receptor desensitization by procainamide.

Introduction: Myelomeningocele (MM) is one of the forms of dysraphism. Hydrocephalus secondary to Arnold-Chiari (AC) malformation is responsible for the morbidity and mortality of the disease. The intrauterine repair of MM may reverse AC and limit hydrocephalus progression., Objective: The aim of this work is to report the successful outcome of a case of intrauterine correction of MM, with favorable evolution and birth at 36 weeks of pregnancy., Case Report: KCMC, 19 years old, was submitted to intrauterine repair of MM at 24 weeks of gestational age after approval by the family and the Research Ethics Committee of the School of Medical Sciences-UNICAMP., Conclusion: Although it is not the standard option for surgical correction, selected MM cases with early fetal diagnosis may be eligible for intrauterine repair, when there is consensus with the Research Ethics Committees and family members.

Background and Objectives: In order to prolong the action and reduce systemic toxicity, formulations of local anesthetic (LA) complexed with cyclodextrins (CD) have been developed. This study determined the physical-chemical characterization and evaluated the effects of inclusion complexes of racemic bupivacaine (S50-R50) and 50% enantiomeric excess (S75-R25) bupivacaine with hydroxypropil-beta-cyclodextrin (HP-beta-CD) in rats, and comparing them with the solutions currently used in the clinical practice., Methods: Inclusion complexation of S75-R25 with HP-beta-CD (equimolar ratio 1:1) was characterized by phase-solubility studies varying the concentrations of HP-beta-CD and the temperature. Affinity constants (K) for HP-beta-CD and the thermodynamic parameters for complexation were determined. Motor and sensitive anesthesias were evaluated through the subarachnoid administration of the formulations in the concentration of 0.5%., Results: Inclusion complexation was observed through the increase in aqueous solubility of LA in different temperatures and concentrations of HP-beta-CD. The in vivo tests demonstrated that S50-R50HP-beta-CD and S75-R25HP-beta-CD reduced latency (p < 0.001) without changing the recovery time of the motor block, time for maximal effect, and total effect of the drugs. Besides, both formulations increased the intensity (1.5 times, p < 0.001) and prolonged the duration of analgesia compared to the free drugs., Conclusions: The complexes S50-R50HP-beta-CD and S75-R25HP-beta-CD potentiated the differential nervous block, and can be used to reduce the frequency of administration or the dose of the LA to induce the same effect. The formulation containing enantiomeric excess (S75-R25) bupivacaine showed to be interesting in the development of safer formulations, and useful for the treatment of acute pain in the postoperative period.

Objectives: To analyze the occurrence of adverse effects in the first 24-hour postoperative/postanesthetic period in women undergoing minor gynecologic or minor breast surgeries and to identify main associated factors., Methods: A cross-sectional study was conducted with 159 women who underwent minor gynecologic or breast surgeries. The women were admitted to the hospital one day before surgery and remained hospitalized for at least 24 hours after surgery. The anesthetic techniques performed were intercostal nerve blockade, spinal anesthesia, and general anesthesia., Results: The most frequent adverse effects were vomiting, nausea and pain that occurred in 40.3% of women. Of these effects, 60% were observed in the first four hours and 80% were observed in up to six hours after surgical intervention. Women submitted to intercostal blockade received earlier postanesthetic release. Spinal anesthesia was most frequently associated with postoperative pain, although with a lower incidence of nausea and vomiting when compared to general anesthesia and intercostal blockade. The incidence of pain was higher in women who smoked., Conclusions: A six-hour period of postoperative observation appeared to be adequate for assessment of most complications and adverse effects occurring in women who undergo minor gynecologic or minor breast surgeries.

Background and Objectives: Ex utero intrapartum treatment (EXIT) is a procedure performed during Cesarean section with preservation of fetal-placental circulation, which allows the safe handling of fetal airways with risk of airways obstruction. This report aimed at describing a case of anesthesia for EXIT in a fetus with cervical cystic hygroma., Case Report: Female patient, 22 years old, 37 weeks gestation without anesthetic background, physical status ASA I, submitted to EXIT for airway handling and tracheal intubation of fetus at risk for airway obstruction. Procedure was performed under general anesthesia associated to continuous epidural anesthesia. Patient was premedicated with intravenous metoclopramide (10 mg) and ranitidine (50 mg). Epidural 0.25% bupivacaine with epinephrine (30 mg) associated to fentanyl (100 mg) was administered, followed by cephalic catheter for postoperative analgesia. Uterus was displaced to the left. Anesthesia was induced in rapid sequence with fentanyl, propofol and rocuronium and was maintained with isoflurane in 2.5 at 3% in O2 and N2O (50%). After hysterotomy, fetus was partially released assuring uterus-placental circulation, followed by fetal laryngoscopy and tracheal intubation. Then fetus was totally released with umbilical cord clamping, administration of oxytocin (20 UI) in continuous infusion, followed by intravenous methyl-ergonovine (0.2 mg). Maternal systolic pressure was maintained above 100 mmHg during the procedure with bolus ephedrine (5 mg) and crystalloids (3000 mL). Isoflurane concentration was gradually decreased during uterine closure. At surgery completion neuromuscular block was reversed and morphine (2 mg) was injected through the epidural catheter for postoperative analgesia., Conclusions: Major recommendations for EXIT are maternal-fetal safety, uterine relaxation to maintain uterine volume and uterus-placental circulation, and fetal immobility to help airway handling.

Background and Objectives: Calcium channel blockers may interact with neuromuscular blockers, increasing its effects. Research studies about this interaction display controversial results. In some studies these drugs produced neuromuscular blockage, or contracture, or no effect at all was proved over skeletal neuromuscular response. This study assessed the nifedipine effects over muscular responses and its possible interaction with neuromuscular blockers in rat diaphragm., Methods: A number of 25 rats were used, weighing between 250 and 300 g and sacrificed under anesthesia with intraperitoneal pentobarbital (40 mg.kg-1). Preparation was mounted according to the technique described by Bulbring. Diaphragm was kept under tension, connected to an isometric transducer and subjected to an indirect stimulation of 0.1 Hz frequency. Diaphragm contractions were registered on a physiograph. In order to evaluate the effect of these drugs on neuromuscular transmission, they were added separately or associated to the preparation, on the following concentrations: nifedipine (4 microg.mL-1); atracurium (20 microg.mL-1); cistracurium (3 microg.mL-1). On phrenic-nerve preparation, the assessed items were: 1) the extent of diaphragm muscle response to indirect stimulation, before and 45 minutes after adding nifedipine and neuromuscular blockers separately and after the association of both drugs; 2) nifedipine effects on membrane potentials (MP) and miniature end-plate potentials (MEPP)., Results: Employed separately, nifedipine did not alter the extent of muscular responses, but it did significantly increase the neuromuscular blocking activity of atracurium and cistracurium. Nifedipine did not alter the membrane potential and caused an initial increase on MEPP frequencies, followed by a blockage., Conclusions: Nifedipine, on the employed concentration, increased the neuromuscular blockage produced by atracurium and cistracurium. Electrophysiological studies demonstrate the existence of presynaptic action and absence of depolarizing action over the muscle fiber.

Background and Objectives: The action mechanism of local anesthetics (LA) on neuromuscular junction motivated several studies. When administered at low doses, they do not interfere on neuromuscular transmission. But high doses may compromise neuromuscular transmission and increase the effects of neuromuscular blockers. The objective of this study was to evaluate lidocaine interaction with rocuronium on rat diaphragm through its influence on neuromuscular block degree., Methods: Rats, weighing between 250 and 300 g, were used. Preparation was set according to the technique described by Bulbring. Groups were formed (n = 5) according to the drug being studied: lidocaine - 20 microg.mL-1 (Group I); rocuronium - 4 microg.mL-1 (Group II), and rocuronium - 4 microg.mL-1 with lidocaine - 20 microg.mL-1 (Group III). The following items were assessed: 1) the extent of diaphragm muscle responses to indirect stimulation, both before and 60 minutes after adding lidocaine and a neuromuscular blocker; 2) membrane potentials (MP) and miniature end-plate potentials (MEPP); 3) the effectiveness of neostigmine, and 4) aminopyridine on neuromuscular blockage reversal., Results: When administered separately, lidocaine did not alter the extent of muscular responses. With the previous use of lidocaine, rocuronium neuromuscular blockage was 82.8% +/- 1.91%, with a significant difference (p = 0.0079) when compared to the group with isolated rocuronium (57.8% +/- 1.9%). Blockage was both partially and fully reverted by neostigmine and 4-aminopyridine, respectively. Lidocaine did not alter membrane potential and caused an initial increase on MEPP, followed by a blockage., Conclusions: Lidocaine increases the neuromuscular blocking produced by rocuronium. MEPP modifications identify a presynaptic action. The complete antagonism of 4-aminopyridine indicates a presynaptic component. This idea is supported by the partial antagonism through neostigmine.

Background and Objectives: Bupivacaine-induced side effects have led to the search for new local anesthetics (LA) with similar potency and lower toxicity, such as bupivacaine enantiomeric mixture (S75-R25). Drug-delivery systems for LA in carriers, such as cyclodextrins (CD), have been developed to improve anesthetic potency and therapeutic index of those drugs. This study aimed at preparing, characterizing and evaluating the anesthetic efficacy of inclusion complexes of bupivacaine enantiomeric mixture (S75-R25) and racemic bupivacaine (S50-R50) with hydroxypropylb- cyclodextrin (HPb-CD) comparing them to clinically available preparations., Methods: Inclusion complexes were obtained by mixing appropriate volumes of HPb-CD and S50-R50 or S75-R25 to final 1:1 or 1:2 molar ratios and were characterized by phase solubility experiments. Affinity constants (K) were determined between HPb-CD and each LA. Motor and sensory blocks induced by plain or complexed LA formulations were evaluated in mice by sciatic nerve block. Three LA concentrations were used during the experiment: 0.125, 0.25 and 0.5%., Results: Solubility experiments results were indicative of S50-R50:HPb-CD and S75-R25:HPb-CD complexation, with similar affinity constant (K) values: 14.7 M-1 and 14,3 M-1, respectively. In vivo experiments have shown that complexation has enhanced differential nerve blockade induced by LA: i) motor blockade duration induced by S75-R25 was similar, to the induced by but less intense S50-R50 ( p < 0.001). S50-R50HPb-CD and S75-R25HPb-CD complexes have decreased onset (p < 0.01 and p < 0.05, respectively), without changing motor block intensity (Emax) as compared to plain drugs; ii) sensory block evaluation has revealed higher analgesic intensity with S50-R50HPb-CD (2-fold, p < 0.001) and S75-R25HPb-CD (1.5-1.8-fold, p < 0.01 and p < 0.001, respectively) with both molar ratios (1:1 and 1:2, LA:CD), in addition to prolonging analgesic effect as compared to S50-R50 and S75-R25., Conclusions: More pronounced analgesic effects obtained by complexation with HPb-CD have shown that both formulations, S50-R50HPb-CD and S75-R25HPb-CD, are very useful for postoperative pain relief, requiring lower LA concentrations. Nevertheless, it is worth noticing that S75-R25 - being less toxic than racemic bupivacaine - is an interesting alternative for the development of more effective and safe drug-delivery systems as compared to racemic bupivacaine (S50-R50).

Background and Objectives: Fetal surgery is the treatment of choices for prenatal malformations that are not adequately corrected after birth and aims at treating or preventing the progression of the abnormalities. This report describes a case of anesthesia for intrauterine correction of a myelomeningocele., Case Report: Pregnant patient, 19 years old, 23 weeks of gestational age, without previous anesthetic history, physical status ASA I, submitted to intrauterine fetal surgery under general anesthesia associated to continuous epidural continuous anesthesia. The patient was premedicated with rectal indomethacin (50 mg), intravenous metoclopramide (10 mg) and cimetidine (50 mg), in addition to intravenous midazolam (2 mg). The patient received 0.25% bupivacaine with epinephrine (25 mg) associated to fentanyl (100 microg) epidurally, followed by cephalic catheter insertion for postoperative analgesia. The uterus was left-displace with a Crawford's wedge. Rapid sequence anesthesia was induced with fentanyl, propofol and rocuronium, and was maintained with 2.5% - 3% isoflurane in O2 and N2O. After stapling hysterectomy to promote homeostasis, fetal operative site was exposed and fetal analgesia and immobility was obtained with the association of fentanyl (10 microg.kg-1) and pancuronium (0.1 mg.kg-1) administered on fetal gluteus muscle. Maternal systolic blood pressure was maintained above 100 mmHg with bolus ephedrine (5 mg), colloids and crystalloids. Lost amniotic fluid was replaced with warm saline. After correction of the fetal defect, both uterus and amniotic membrane were closed in two planes with vicryl suture and fibrin glue. Afterwards, isoflurane concentration was gradually decreased and bolus magnesium sulfate (4 g/20 minutes) followed by continuous infusion was administered to maintain uterine relaxation (2 g/hour). Morphine (2 mg) was administered via epidural catheter at the end of surgery for postoperative analgesia., Conclusions: Anesthesia for fetal surgery involves two individuals the mother and the fetus, an anesthetic management requires: maternal-fetal safety, fetal anesthesia and immobility, uterine relaxation, prevention of premature labor and postoperative analgesia.

Background and Objectives: Factors associated to patients and neuromuscular blockers (NMB), as well as others inherent to neuromuscular function monitoring, may affect neuromuscular block onset. This study aimed at the influence of two different stimulation frequencies on rocuronium and pancuronium-induced neuromuscular block., Methods: Participated in this study 120 patients, physical status ASA I and II, submitted to elective procedures under general anesthesia, who were randomly allocated in two groups, according to the stimulation frequency employed to monitor neuromuscular block: Group I - 0.1 Hz (n = 60) and Group II - 1 Hz (n = 60). Two subgroups were formed within each group (n = 30), according to the neuromuscular blocker: Subgroup P (pancuronium) and Subgroup R (rocuronium). Patients were premedicated with muscular midazolam (0.1 mg kg(-1)), 30 minutes before surgery. Anesthesia was induced with propofol (2.5 mg kg(-1)) preceded by alfentanil (50 microg kg(-1)) and followed by pancuronium or rocuronium. Patients were ventilated under mask with 100% oxygen until 75% or more decrease in adductor pollicis muscle response, when laryngoscopy and tracheal intubation were performed. Neuromuscular function was monitored by acceleration transducer. The following parameters were evaluated: pancuronium and rocuronium onset time; time for complete block and tracheal intubation conditions., Results: Mean times (seconds) for pancuronium-induced neuromuscular block onset and for complete neuromuscular block were: Group I (159.33 +/- 35,22 and 222 +/- 46.56) and Group II (77.83 +/- 9.52 and 105.96 +/- 15.58); rocuronium-induced values were: Group I (83 +/- 17.25 and 125.33 +/- 20.12) and Group II (48.96 +/- 10.16 and 59.83 +/- 10.36) with statistical difference between groups. Tracheal intubation conditions were satisfactory in 117 patients (97.5%) and unsatisfactory in 3 (2.5%)., Conclusions: Rocuronium and pancuronium-induced neuromuscular block onset and time required for complete adductor pollicis muscle neuromuscular block are shorter when higher stimulation frequencies are applied.

Background and Objectives: Many researchers in the last four decades have been devoted to the development of drug-delivery systems. Since its first application in the pharmaceutical industry, many results have been obtained especially in the molecular manipulation of carriers and their interaction with encapsulated drugs. These new carriers have the advantage of bypassing encapsulated drugs restraining physicochemical properties (such as water or membrane solubility), thus improving pharmacodynamics (therapeutic effect potentiation), pharmacokinetics (control of tissue absorption and distribution) and toxic effects (lower local and systemic toxicity). Liposomes and cyclodextrins are among the most important carriers which have shown to be quite advantageous in the development of drug-delivery systems for local anesthetics. This study aimed at reviewing the interaction of local anesthetics with liposomes and cyclodextrins, the development of basic and applied research on the field, in addition to therapeutic applicability of these formulations., Contents: Liposomes have the ability to control drug delivery to target tissues, fractionating drug release in its site of action. Cyclodextrins, on the other hand, change intensity and duration of effects due to low systemic drug absorption. Basic and clinical studies have pointed out that the administration of local anesthetics in liposome or cyclodextrin formulations induces slow release of the drugs, prolonging the anesthetic action and decreasing cardiac and nervous systems toxicity., Conclusions: Although studies are still in progress, drug-delivery systems are flagging a new direction for the development of safer and more effective local anesthetic formulations.

Background and Objective: Subarachnoid block is a widely used technique for Caesarean section. Its quality can be improved by adding opioids to the local anaesthetics. We studied the quality of the block and its maternal-fetal repercussions when different doses of sufentanil were combined with hyperbaric bupivacaine using the intrathecal route in pregnant women undergoing Caesarean section., Methods: This was a prospective, randomized, double-blind, controlled trial with 80 pregnant women, ASA I-II, who were scheduled for elective Caesarean section under subarachnoid block. Patients were distributed into four groups according to the dose of sufentanil used: no sufentanil (Group 1, control) or 2.5, or 5.0 or 7.5 microg sufentanil (Groups 2-4, respectively). In every group, the local anaesthetic used was hyperbaric bupivacaine 0.5% (12.5 mg) and the total volume of the solution 4 mL. The onset time of the block, maximum level of sensory block, motor block level, duration of analgesia, maternal side-effects and maternal-fetal cardiovascular repercussions were evaluated., Results: Onset of the block was significantly shorter in the groups receiving opioids compared with the control group. Analgesia was significantly prolonged in Groups 3 and 4. The occurrence of pruritus and somnolence was significantly higher in the group receiving sufentanil 7.5 microg than in other groups. With the exception of pruritus, no differences were observed between groups with respect to cardiovascular or other maternal effects., Conclusions: The addition of sufentanil 5.0 and 7.5 microg to hyperbaric bupivacaine provided adequate anaesthesia for Caesarean section and good postoperative analgesia. Pruritus was the most common side-effect and had a significantly higher incidence when a dose of sufentanil 7.5 microg was used.

Background and Objectives: The priming technique is an alternative to shorten nondepolarizing neuromuscular blockers onset time. This study aimed at evaluating maximum neuromuscular block onset, tracheal intubation conditions and cardiocirculatory changes determined by different cisatracurium single or fractional doses., Methods: Participated in this study 80 patients physical status ASA I and II, who were distributed into two groups according to cisatracurium doses: Group I (0.1 mg.kg-1) and Group II (0.2 mg.kg-1). Subgroups were constituted according to the curarization technique employed: subgroups P1 and P2 (priming-dose) - 0.02 mg.kg-1 or 0.04 mg.kg-1cisatracurium, respectively, followed one minute later, by 0.08 mg.kg-1 or 0.16 mg.kg-1 of the same neuromuscular blocker, respectively; subgroups U1 and U2 - total bolus injection of 0.1 mg.kg-1 or 0.2 mg.kg-1 cisatracurium, respectively. Anesthesia was induced with etomidate, preceded by alfentanil. Train of Four (TOF) stimulation was applied at 12-second intervals to monitor neuromuscular function. Maximum neuromuscular blockade onset time, tracheal intubation conditions and changes in hemodynamic parameters (arterial mean blood pressure and heart rate) were evaluated., Results: Mean times for maximum neuromuscular block onset were: Group I (3.90 +/- 0.60 min and 3.88 +/- 0.74 min, for subgroups P1 and U1, respectively) and Group II (1.40 +/- 0.40 min and 2 +/- 0.30 min, for subgroups P2 and U2, respectively) with no significant differences. Comparison between subgroups P1 and P2 and between subgroups U1 and U2, has shown statistically significant differences. Tracheal intubation conditions were acceptable in all patients and there were no cardiovascular changes., Conclusions: Fractional cisatracurium doses have not shortened maximum neuromuscular block onset as compared to bolus injections. They have however produced acceptable tracheal intubation conditions without cardiovascular changes.

Background and Objectives: Some hypnotics may interact with neuromuscular blockers and potentiate their effects. This study aimed at evaluating the influence of propofol and etomidate on rocuronium-induced neuromuscular block., Methods: Participated in this study 60 patients, physical status ASA I and II, scheduled for elective surgeries under general anesthesia, who were randomly distributed in two groups according to the hypnotic drug: Group I (propofol) and Group II (etomidate). All patients were premedicated with intramuscular midazolam (0.1 mg.kg-1), 30 minutes before surgery. Anesthesia was induced with propofol (2.5 mg.kg-1) or etomidate (0.3 mg.kg-1) preceded by alfentanil (50 microg.kg-1) and followed by rocuronium (0.6 mg.kg-1). Patients were ventilated under mask with 100% oxygen until achieving a decrease of 75% or more in the adductor pollicis muscle response amplitude. Neuromuscular function was monitored by accelerometry. The following parameters were evaluated: rocuronium onset (T1 <= 25%); time for complete neuromuscular block; neuromuscular block degree at tracheal intubation; tracheal intubation conditions and hemodynamic effects., Results: Complete rocuronium-induced neuromuscular block onset times (in seconds) were: Group I (48.20 +/- 10.85 s and 58.87 +/- 10.73 s) and Group II (51.20 +/- 13.80 s and 64.27 +/- 18.55 s). Neuromuscular block degree at tracheal intubation was: Group I (77.50%) and Group II (76.96%). Tracheal intubation conditions were satisfactory in 100% of Group I patients and in 83.33% of Group II patients. There has been a significant decrease in mean blood pressure, followed by an increase after hypnotic injection, in both groups., Conclusions: Propofol and etomidate had a similar behavior regarding time for rocuronium-induced neuromuscular block and tracheal intubation conditions.

Background and Objectives: The effects of neuromuscular blockers on the neuromuscular junction are potentiated by volatile anesthetics. This study aimed at evaluating the influence of sevoflurane and isoflurane on the recovery of cisatracurium- induced neuromuscular block., Methods: Ninety ASA I and II patients undergoing elective surgeries under general anesthesia were included in this study. Patients were allocated in three groups: Group I (sevoflurane), Group II (isoflurane) and Group III (propofol). All patients were premedicated with intramuscular midazolam (0.1 mg.kg-1) 30 min before surgery. Anesthesia was induced with alfentanil (50 microg.kg-1), propofol (2.5 mg.kg-1) and cisatracurium (0.15 mg.kg-1). Patients were then ventilated under mask with 100% O2 until disappearance of all TOF responses when laryngoscopy and tracheal intubation were performed. Volatile agents for anesthetic maintenance were introduced immediately after tracheal intubation in 2% and 1% concentrations, respectively, for sevoflurane and isoflurane, as well as the propofol continuous infusion (7 to 10 mg.kg-1.h-1) for Group III. All patients received a 50% mixture of O2 and N2O. Neuromuscular function was monitored by adductor pollicis muscle acceleromyography with TOF stimulation at 15-second intervals. Clinical duration of neuromuscular block (T1(25%)) and recovery index (RI=T1(25-75%)) were evaluated., Results: Mean time and standard deviation for clinical duration (T1(25%)) and recovery index (RI=T1(25-75%)) were respectively: Group I (66.2 +/- 13.42 min and 23.6 +/- 5.02 min), Group II (54.4 +/- 6.58 min and 14.9 +/- 3.82 min) and Group III (47.2 +/- 7.43 min and 16.2 +/- 2.93 min). There were significant differences in clinical duration between Groups I and II, I and III and II and III. There was a significant difference in recovery index between Group I and the other groups., Conclusions: The recovery from cisatracurium-induced neuromuscular block was longer during anesthesia with volatile agents as compared to propofol. The most pronounced effect was observed with sevoflurane.