Shorter Onset Time Research Articles

A comparison of the vertical infraclavicular and axillary approaches for brachial plexus anaesthesia

This prospective, randomized study compared the efficacy of the vertical infraclavicular and axillary approaches using a single injection blockade of the brachial plexus. The primary endpoint was complete blockade in dermatomes C5-Th1, while secondary endpoints included onset time, motor block, block performance time, surgical success rate, patient satisfaction, and side-effects/complications. Sixty patients, American Society of Anesthesiologists physical status I or II, scheduled for surgery of the forearm or hand received either a vertical infraclavicular (n = 30) or an axillary block (n = 30). A single injection of 0.5 ml/kg ropivacaine 7.5 mg/ml was made after electrolocalization of nerve fibres corresponding to the median nerve at maximum 0.5 mA (2 Hz, 0.1 ms). Onset and distribution of analgesia and motor block were assessed at 5, 10, 15, 20, 30 and 60 min after the local anaesthetic injection. A complete block was defined as analgesia in all dermatomes (C5-Th1) at 60 min post-injection. The vertical infraclavicular approach provided complete blockade in 29 patients (97%) and the axillary approach in 23 patients (77%). Analgesia in C5-C6 dermatomes and corresponding motor block occurred significantly more frequently in the vertical infraclavicular approach, which also had the shortest onset time. Block procedure was quicker in the axillary approach. Side-effects were similar in both groups, and there were no permanent sequelae. Patient satisfaction was equally high in both groups. The vertical infraclavicular approach provides a more complete block than the axillary approach when using a single injection technique and equal volumes/doses of local anaesthetic.

Sciatic nerve block with 0.5% levobupivacaine, 0.75% levobupivacaine or 0.75% ropivacaine

This prospective, randomized, double-blind study was conducted to evaluate the onset time and duration of sciatic nerve block produced with 0.5% levobupivacaine, 0.75% levobupivacaine and 0.75% ropivacaine. Forty-five healthy patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block with levobupivacaine 0.5% (n=15), levobupivacaine 0.75% (n=15) or ropivacaine 0.75% 20 mL (n=15). A femoral nerve block was also performed with mepivacaine 2% 15 mL to cover pain related to the thigh tourniquet. A blinded observer recorded the onset time and duration of sciatic nerve block. The median (range) onset time was 5 (5-40) min with 0.75% levobupivacaine, 30 (5-60) min with 0.5% levobupivacaine and 20 (5-50) min with 0.75% ropivacaine (P = 0.02 and P = 0.12, respectively). Mean (25-75 percentiles) first request for pain medication occurred after 13 (11-14) h with 0.75% ropivacaine, 18 (15-19) h with 0.75% levobupivacaine and 16 (13-20) h with 0.5% levobupivacaine (P = 0.002 and P = 0.002, respectively). Rescue tramadol after surgery was required by three patients in the 0.75% levobupivacaine group, eight patients in the 0.5% levobupivacaine group and nine patients in the 0.75% ropivacaine group (P = 0.05). We conclude that 0.75% levobupivacaine provides a shorter onset time than 0.5% levobupivacaine and a longer duration of postoperative analgesia than both 0.5% levobupivacaine and 0.75% ropivacaine with reduced need for rescue analgesia after surgery.

Spinal versus epidural anaesthesia for caesarean section

Regional anaesthesia (spinal or epidural anaesthesia) for caesarean section is the preferred option when balancing risks and benefits to the mother and her fetus. Spinal anaesthesia for caesarean section is thought to be advantageous due to simplicity of technique, rapid administration and onset of anaesthesia, reduced risk of systemic toxicity and increased density of spinal anaesthetic block. To assess the relative efficacy and side-effects of spinal versus epidural anaesthesia in women having caesarean section. The Cochrane Pregnancy and Childbirth Group Trials Register (February 2003) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2003). Types of studies considered for review include all published randomised controlled trials involving a comparison of spinal with epidural anaesthesia for caesarean section. Two reviewers independently assessed trials for inclusion. Review Manager software was used for calculation of the treatment effect represented by relative risk (RR) and weighted mean difference (WMD) using a random effects model with 95% confidence intervals (CI). Ten trials (751 women) met our inclusion criteria. No difference was found between spinal and epidural techniques with regards to failure rate (RR 0.98, 95% CI 0.23 to 4.24; four studies), need for additional intraoperative analgesia (RR 0.88, 95% CI 0.59 to 1.32; five studies), need for conversion to general anaesthesia intraoperatively, maternal satisfaction, need for postoperative pain relief and neonatal intervention. Women receiving spinal anaesthesia for caesarean section showed reduced time from start of the anaesthetic to start of the operation (WMD 7.91 minutes less (95% CI -11.59 to -4.23; four studies), but increased need for treatment of hypotension RR 1.23 (95% CI 1.00 to 1.51; six studies). Both spinal and epidural techniques are shown to provide effective anaesthesia for caesarean section. Both techniques are associated with moderate degrees of maternal satisfaction. Spinal anaesthesia has a shorter onset time, but treatment for hypotension is more likely if spinal anaesthesia is used. No conclusions can be drawn about intraoperative side-effects and postoperative complications because they were of low incidence and/or not reported.

Comparison of three different volumes of mepivacaine in axillary plexus block using multiple nerve stimulation

The multiple injection technique for axillary block, in which the four distal nerves of the plexus are located by a nerve stimulator and separately injected, has been shown to provide a high success rate and a short onset time. This randomized double-blind study was conducted to compare the effectiveness of three different volumes of mepivacaine 10 mg x ml(-1) in patients undergoing elective distal upper limb surgery under axillary brachial plexus block with the four-nerve approach. The number of complete sensory blocks was the primary efficacy variable. A total of 114 adult patients were randomly allocated to receive 36 (n=38), 28 (n=38), and 20 ml (n=38) of mepivacaine 10 mg x ml(-1). In each group, volumes were equally distributed in the four nerve territories. In all patients, performance time, latency time, block characteristics, need of supplementary blocks, tourniquet tolerance, duration of analgesia, and complications were recorded. Complete sensory block was obtained in 97% of patients receiving a volume of 36 ml, 97% of those receiving 28 ml, and 94% of those receiving 20 ml. One patient in the group of 28 ml and five patients in the group of 20 ml experienced pain on inflation of the tourniquet. Two months after surgery, no case of postoperative neurological dysfunction was observed. The three volumes (38, 28, and 20 ml) of mepivacaine 10 mg x ml(-1) ensured a similar and high percentage of complete sensory blocks in axillary brachial plexus anaesthesia with nerve stimulation involving the location of four motor responses.

Comparison of the Parasacral Approach and the Posterior Approach, with Single- and Double-Injection Techniques, to Block the Sciatic Nerve

The purpose of this study was to compare parasacral and Winnie's single- or double-injection approaches for sciatic nerve block. One hundred fifty adults scheduled to undergo lower limb surgery were randomized to receive on the sciatic nerve 20 ml ropivacaine, 0.75%: single bolus for parasacral and Winnie's single injection. For Winnie's double injection, the peroneal and tibial nerves received separately 10 ml plus 10 ml. Blocks were performed with the use of nerve stimulator (intensity < 0.5 mA, 1 Hz). For the parasacral method, a line was drawn between the posterior superior iliac spine and the ischial tuberosity; needle entry was at 6 cm inferior to the posterior superior iliac spine. The groups were similar. Time to perform the block was 2 (1-5) min for the parasacral method, with no difference from Winnie's single injection (3 [1-10] min), but was shorter with double injection (5.5 [2-15] min) (P = 0.0001). Onset of sensory block was similar in the parasacral (25 [7.5-50] min) and Winnie single-injection groups (25 [5-50] min) but significantly longer in the double-injection group (15 [5-50] min). Success rates for complete block were similar in the parasacral (66%) and Winnie's double-injection groups (68%) after 30 min but higher in the Winnie's single-injection group for tibial sensory and motor block (48%) (P < 0.017). Time to perform a parasacral block was short, and the parasacral approach had a high success rate and a short onset time. Therefore, this block might be a useful alternative to Winnie's modification for sciatic nerve block.

The use of muscle relaxants for routine induction of anesthesia in Germany

The aim of this study was to evaluate the use of muscle relaxants during induction of anesthesia in patients without risk of aspiration of stomach contents. Of the 2,996 questionnaires sent out, 2,054 (68.6%) could be analysed and the results show that succinylcholine is used regularly in 13.6% of anesthesia departments. The next most commonly used muscle relaxants are atracurium, vecuronium and mivacurium, followed by cis-atracrium, rocuronium and pancuronium. Alcuronium is the least frequently used muscle relaxant. During induction of an elective anesthesia procedure, a priming technique is used by 19% of anesthesiologists, 22% utilize precurarization, and a timing technique is performed in 7.1%. The use of muscle relaxants for on-going relaxation follows the same pattern as for induction of neuromuscular blockade and succinylcholine is used in 1.4% if further relaxation is needed. The desire for specific qualities of muscle relaxants is correlated with higher use of the specific substance: short onset time for rocuronium, good controllability with mivacurium, no side-effects with cisatracurium and economical aspects with alcuronium. Of the participants 76.6% voiced the desire for a non-depolarizing replacement for succinylcholine.Private practices use mivacurium more often than hospitals, level one hospitals use rocuronium and cisatracurium more often. This survey could not show a definite standard of use in terms of muscle relaxants for an elective case.Precurarization, priming and timing are used frequently in patients not at risk of aspiration. This should be reduced by on-going teaching.

Onset Time and Duration of Action of Neuromuscular Blockade with Rocuronium in Major Burn Patients

Background: It is well known that bum patients are resistant to the actin of nondepolarizing muscle relaxants. Rocuronium, with a shorter onset time and freedom from electrolyte side effcts, may be considered for rapid sequence induction in these circumstances. This randomized, double-blind study was conducrd to assess the onset time, duration of action of neuromusculn blockades and the intubating conditions induced by rocuronium ri major bum patients. Methods: Adult patients, suffered from major bum injury, aged 18- 59 years, ASA physical status I or II, more than 4 weeks and less than 6 months after the initial injury, were included. Propofol and fentanyl based intravenous anesthesia was condued with nitrous-oxide and oxygen. Neuromuscular blockade was morrored by acceleromyography, TOF-Watch (Organon Teknika B.V., Boseind, The Netherlands), using Train-of-Four (TOF) stimulation, Rocuronium (Esmeron, Organon Inc, USA), at ED 3 (0.9 mg/kg) and ED 4 (1.2 mg/kg) were given intravenously over 5 s in both groupsof bum and nonburn patients, respectively. Onset time, duration of action, and intubating conditions wereassessed and graded according to the Guidelines for Good Clinial Research Practice. Results: Average bum TBSA were between 30% and 40%, and the elapsed itne after the initial injury was approximately a month. Demographic data revealed no significant differences btween bum and nonbum groups. The average time to 95% neuromuscular block was significantly prolonged in the bum gmp compared to the non-bum group (115.0 58.4 vs. 68.4 15.8 sec at 0.9 mg/kg, 86.1 19.7 vs. 56.9 10.9 sec at 1.2 mg/kg, P

Dilemma In Rapid Sequence Intubation: Succinylcholine Vs. Rocuronium

Succinylcholine is the single ultra-short acting depolarizing neuromuscular blocking agent (NMBA) used in the rapid sequence intubation protocol with its rapid onset of effect, complete reliability, short duration of action. Rocuronium is diverse from other non-depolarizing NMBA being the first one with a short onset time and devoid of untoward effects. Despite its widespread use, succinylcholine has several potential hazards including an increase in potassium levels, bradycardia for children and prolonged apnea for those with pseudocholinesterase deficiency. Rocuronium is indicated in subjects with disease states such as known or suspected hyperkalemia, crush injury, non-acute burns, increased intracranial or intraocular pressure and neuromuscular disease. Although succinylcholine has many side effects, it remains to be the first-choice NMBA for the majority of attempts for rapid sequence intubation. Rocuronium may be a suitable alternative to succinylcholine with its short onset time. The objective of this article is to update data from studies comparing the use of succinylcholine and rocuronium in rapid sequence intubation protocol in adults.

Combination Spinal Analgesic Chemotherapy: A Systematic Review

Combination Spinal Analgesic Chemotherapy: A Systematic Review

Combination spinal analgesic chemotherapy: a systematic review.

Combination spinal analgesic chemotherapy: a systematic review.

Antimicrobial Effectiveness of Povidone-Iodine and Consequences for New Application Areas

The microbicidal action spectrum of povidone-iodine (PVP-I) is broad – even after short onset times. Unlike local antibiotics and other antiseptic substances, no resistance develops. The high degree of bactericidal efficiency in respect of highly resistant gram-positive pathogenic micro-organisms, such as methicillin-resistant Staphylococcus aureus (MRSA) and enterococcus strains, is particularly significant for hospital hygiene. An in vitro study with 10 genotypically different MRSA isolates showed an optimum bactericidal effect (logarithmic reduction factor value >5) without protein load after just 30 s exposure and even in a dilution of Betaisodona^® solution (Mundipharma GmbH) of 1%. With protein load (0.2% albumin), the optimum in microbicidal effectiveness shifts to concentrations ≧10% Betaisodona solution referring to an exposure time of 30 s. Since recent results are now also available on the toxicological safety of PVP-I preparations for the ciliated epithelium of the nasal mucosa and the good tolerability on skin and other mucous membranes is a known factor, a controlled clinical study is currently being carried out to eliminate colonizations of MRSA. Evidence has also recently been produced of the antiviral activity of PVP-I against herpes simplex, adeno- and enteroviruses, as well as its high degree of efficiency against Chlamydia. Hence alongside the classical fields of application, such as the disinfection of the skin and hands, mucosa antisepsis and wound treatment, there are also useful indications for the substance, i.e. rinsing of body cavities and joints and application to the eye.

Motor Control Across Trophic Strategies: Muscle Activity of Biting and Suction Feeding Fishes

Many fishes use a powerful bite of the oral jaws to capture or tear their prey. This behavior has received less study from functional morphologists and physiologists than suction feeding, and presents an opportunity to examine motor control of fish feeding across alternative prey-capture strategies. We used electromyography to compare muscle activity patterns of the feeding bite in five teleost fishes representing at least three lineages in which biting has been independently acquired: two parrotfish (Cetoscarus bicolor and Scarus iseri), a wrasse (Cheilinus chlorourus), and two serrasalmines, a pacu (Piaractus brachypomus) and a piranha (Pygocentrus nattereri). Multivariate analysis indicated that muscle activity patterns differed significantly among species, although a four-way ANOVA designed to test for differences within a phylogenetic hierarchy revealed that the biting motor pattern was largely similar for both narrow and broad phylogenetic comparisons. A comparison of the motor patterns of biting and suction feeding species revealed that biters had significantly shorter durations of the epaxialis and sternohyoideus and significantly longer relative onset times of the epaxialis, adductor mandibulae, and sternohyoideus. Character mapping of timing variables suggested that short relative onset times are primitive for suction feeders and that this characteristic is generally retained in more advanced species. Despite these differences, all species overlap extensively in multivariate EMG space. Our results demonstrate that change in the feeding motor pattern has accompanied morphological and behavioral change in transitions from suction to biting, which suggests that the neuromotor system has not acted as a constraint on the evolution of the feeding system in fishes.

Motor Control Across Trophic Strategies: Muscle Activity of Biting and Suction Feeding Fishes1

Many fishes use a powerful bite of the oral jaws to capture or tear their prey. This behavior has received less study from functional morphologists and physiologists than suction feeding, and presents an opportunity to examine motor control of fish feeding across alternative prey-capture strategies. We used electromyography to compare muscle activity patterns of the feeding bite in five teleost fishes representing at least three lineages in which biting has been independently acquired: two parrotfish (Cetoscarus bicolor and Scarus iseri), a wrasse (Cheilinus chlorourus), and two serrasalmines, a pacu (Piaractus brachypomus) and a piranha (Pygocentrus nattereri). Multivariate analysis indicated that muscle activity patterns differed significantly among species, although a four-way ANOVA designed to test for differences within a phylogenetic hierarchy revealed that the biting motor pattern was largely similar for both narrow and broad phylogenetic comparisons. A comparison of the motor patterns of biting and suction feeding species revealed that biters had significantly shorter durations of the epaxialis and sternohyoideus and significantly longer relative onset times of the epaxialis, adductor mandibulae, and sternohyoideus. Character mapping of timing variables suggested that short relative onset times are primitive for suction feeders and that this characteristic is generally retained in more advanced species. Despite these differences, all species overlap extensively in multivariate EMG space. Our results demonstrate that change in the feeding motor pattern has accompanied morphological and behavioral change in transitions from suction to biting, which suggests that the neuromotor system has not acted as a constraint on the evolution of the feeding system in fishes.

Perception of aspiration and place of articulation of Cantonese initial stops by normal and sensorineural hearing‐impaired listeners

This study investigated the use of acoustic cues to the perception of aspiration and place of articulation of Cantonese initial stops by bilateral severely hearing-impaired (n = 14) and normal-hearing (n = 14) adolescents. The stimuli were consonant-vowel (CV) words spoken by two male speakers in which the initial consonants /ph, p, th, t, kh, k/ were followed by the diphthong /[symbol: see text]i/. Subjects listened to the stimuli through a loudspeaker and chose the correct initial consonant among six choices. Three test conditions (short, medium and long voice onset time, or VOT) were prepared by increasing the VOT of unaspirated stops and by decreasing the VOT of aspirated stops. The results showed that the presence of aspiration noise was an important cue for normal listeners in the perception of aspiration, but not for hearing-impaired listeners. Hearing-impaired listeners used formant transitions as the main cue to the perception of aspiration. VOT was a weak aspiration cue for both groups. In the perception of place of articulation, normal listeners appeared to rely mainly on formant transitions and release burst information rather than VOT. The recognition of place by hearing-impaired listeners was at chance level for all the experimental stimuli, showing that these listeners were unable to use VOT, formant transitions or release burst information as cues to place.

Intoxications aiguës par neurotoxiques organophosphorés : insecticides et armes chimiques

Objective: To review clinical and therapeutic bases of an organophosphate poisoning, either with insecticide or nerve agent. Data sources: References were obtained from computerized bibliographic research (Medline®), from personal data (academic memoir, documents under approbation of the National Defense Office), from Internet’s data. Data synthesis: Generally, organophosphate poisoning occurs during accidental exposure with agricultural insecticide or suicide. The effects of organophosphate coumpounds are due to the inhibition of the enzyme acetylcholinesterase. The intoxication symptoms can be divided into muscarine-like, nicotine-like effects, effects on the central nervous system and symptoms related to the dysfunction of the neuromuscular junction. The interest of biological acetylcholinesterase’s measuring is minimal because it is weakly specific or sensitive. The immediate severity is due to hypoxia. Respiratory failure results from the lack of central drive inflated with excessive bronchial secretions, bronchospasm and respiratory muscles paralysis. The secondary complications are early myopathies whose gravity is correlated with the decrease of acetylcholinesterases, or later neuropathies induced by a different mechanism. Beside the symptomatic mesures, atropine is the specific anticholinergic treatment. When promptly used, oximes can regenerate cholinesterases. The attempted effects of the treatment are mouth dryness, pupilar dilatation and flushing of the skin. Nerve agents are lethal toxics which have a short onset time and produce severe neurological pathology. In a terrorist incident, it is as important to identify rapidly the toxic agent and provide emergency decontamination as to manage medical care. An effective response must be multidisciplinary, involving clinicians, toxicologists, Emergency Medical Service and public’s health personnel.

Design and synthesis of anticonvulsive agents as γ-vinyl GABA-based potential dual acting prodrugs and their biological activities

For the development of new anticonvulsive agents, γ-vinyl GABA (vigabatrin) and GABA mimetics derivatives were covalently coupled as potential dual acting prodrugs and evaluated for their anticonvulsive activities. Among the prepared compounds, 11 showed the most potent anticonvulsive activity, a shorter onset time and a broader spectrum compared to vigabatrin.

Cost analysis of neuromuscular blocking agents in the operating room: cisatracurium, atracurium, vecuronium and rocuronium.

Cisatracurium (C), Atracurium (A), Rocuronium (R) and Vecuronium (V) are four neuromuscular blockers (NMB) used in the operating room with similar efficacy, defined as adequate muscle relaxation, but different pharmacokinetics. C and A have organ-independent elimination, A is associated with histamine release and R has a shorter onset time. The objective of this study was to economically compare these four NMB from the hospital point of view in order to facilitate drug selection. A cost analysis was performed. Only direct costs were considered and data were collected through a retrospective chart review. A total of 151 patient charts were randomly selected. Differences between patients receiving one of the four NMB were evaluated by ANOVA or Kruskal-Wallis tests. Then a multiple linear regression analysis was conducted. In the chart review, no significant difference was observed between the four groups of patients in age, weight or surgery duration (p > 0.05). Multiple regression analysis revealed that atracurium was on average PTA 237 (1 Euro = PTA 166) cheaper per surgery than any other NMB after adjusting for other factors (p < 0.01) and there is no significant difference in cost between the other three NMBs (p > 0.1). We recommend the use of rocuronium when a quick onset is needed and the patient does not have hepatic failure, cisatracurium when a haemodynamic instability is possible and atracurium in the remaining cases. If just one NMB can be included in the drug formulary we would select cisatracurium due to its pharmacological advantages over atracurium with a small increment in cost.

A clinical comparison of ropivacaine 0.75%, ropivacaine 1% or bupivacaine 0.5% for interscalene brachial plexus anaesthesia

In order to compare interscalene brachial plexus block performed with ropivacaine or bupivacaine, 45 healthy, unpremedicated patients, undergoing elective shoulder surgery, were randomly allocated to receive interscalene brachial plexus anaesthesia with 20 mL of either ropivacaine 0.75% (n = 15), ropivacaine 1% (n = 15), or bupivacaine 0.5% (n = 15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved later with bupivacaine 0.5% (28 ±15 min) than with ropivacaine 1% (10±5 min) (P = 0.005) and ropivacaine 0.75% (15±8 min) (P=0.0005). No differences in success rate were observed between the three groups; however, seven patients receiving bupivacaine 0.5% required intra-operative analgesic supplementation (fentanyl 0.1 mg intravenous) compared with one patient receiving ropivacaine 0.75%, and two patients treated with ropivacaine 1% (P=0.02). The time from the block placement to first request for pain medication was similar in the three groups (10.7 ± 2 h, 11 ± 2.4 h, and 10.9 ± 3.9 h after 0.75% and 1% ropivacaine or 0.5% bupivacaine, respectively). We conclude that interscalene brachial plexus block performed with 20 mL of either 0.75% or 1% ropivacaine allows for a prolonged post-operative pain relief, similar to that provided by bupivacaine 0.5%, with short onset time of surgical anaesthesia.

The use of curare-like agents in resuscitation

To analyse current data on use of neuromuscular blocking agents (NBA) in the intensive therapy unit (ITU) patients and to propose practice guidelines. We did a Medline search of French and English language articles on NBA administration in ITU patients from 1960 to 1998. Data were also selected from our own collection of articles and books. Original articles, clinical cases, letters to the editor and review articles were considered. Data on pharmacology of NBA in the ITU patient were extracted, as well as data on administration patterns and cost. The indications for myorelaxation in ITU patients include either short term use, as in anaesthesia, or long term administration for facilitation of mechanical ventilation, control of increased intracranial pressure, status epilepticus, tetanus and oxygen demand in case of muscular hyperactivity, diagnostic and therapeutic procedures facilitation. A beneficial effect of NBA on the prognosis of the disease for which these agents have been used is not yet proven. Suxamethonium, because for its short onset time and duration of action, is the agent of choice for endotracheal intubation if myorelaxation is required. Among the benzylisoquinolines, atracurium and besilate of cisatracurium are convenient agents in ITU patients, whereas mivacurium is of no special interest. Among the aminosteroids, pancuronium and vecuronium are the most often used agents in the ITU. Rocuronium has not yet been extensively assessed. Myorelaxants carry risks for morbidity and mortality. The difficulty to assess the neurological status and the level of sedation is a recognised adverse effect. An accidental disconnection from the circuit and the resulting asphyxia is nowadays recognised without delay by the ventilator. NBAs increase the rate of bronchopulmonary infections. Cardiovascular complications include extreme bradycardia or sinus arrest following vecuronium administration, and cardiac arrest after suxamethonium injection mainly in burned or traumatised patients. Conversely to anaesthesia, NBAs do not carry a significant risk for anaphylactic or anaphylactoid complications in the ITU. Tachyphylaxis occurs mainly in burns and other pathologies modifying acetylcholine receptors. Neuromuscular complications include myopathy from steroids, postparalytic syndrome, deconditioning syndrome and intensive care polyneuropathy. Prolonged curarisation after discontinuation of NBA administration has a multifactorial origin and must be differentiated from neuromuscular complications. For prolonged neuromuscular blockade, pancuronium, vecuronium and atracurium are the agents of choice. The association with an adequate sedation is essential. Assessment of depth of neuromuscular blockade is not based on clinical symptoms but on train-of-four (TOF) twitch monitoring. A convenient basic relaxation is usually obtained with the suppression of the two last responses to TOF. The use of NBA in ITU patient should result from a rational decision making procedure, the blockade titrated with a TOF monitor and maintained as superficially and shortly as possible.

Block of NMDA receptors by a newly synthesized analog of milnacipran in cultured mouse hippocampal neurons

Immature hippocampal neurons with high input resistances (Rin) are vulnerable to hyperexcitable or epileptogenic conditions. This phenomenon has been suggested to explain the neuroprotective roles of hyperpolarization-activated cation channels (Ih channels) to regulate membrane Rin. In the present study, we tried to electrophysiologically clarify the relationship between membrane Rin and Ih channels and determine the neuroprotective roles of these channels in development. The CA1 neurons from rats (within 3 postnatal weeks) were classified into two groups based on the onset time (shorter or longer than 20 ms) to fire the first action potential (AP) in response to a current injection (100 pA, 800 ms). Neurons with a shorter onset time (Short-OsT), exhibited higher Rin, while neurons with longer onset times (Long-OsT) revealed lower Rin. Unexpectedly, Short-OsT neurons with higher Rin exhibited larger amplitudes of Ih compared with Long-OsT neurons. Furthermore, the application of temporal depolarization stimulus (TDS, −14 mV holding for 150 s) significantly enhanced suprathreshold excitabilities of repetitive APs in Long-OsT but not Short-OsT neurons, suggesting a protective role of Ih channels under high Rin conditions. In the presence of the specific hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker ZD7288, TDS also enhanced the excitability of Short-OsT neurons, suggesting that young CA1 neurons regulate Ih channel expression for neuroprotective modulation against epileptogenic conditions.