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Large-scale antenna arrays are a promising solution to cope with the severe attenuation associated with millimeter-wave bands. Pencil beams require significant signaling overhead for alignment, especially if explicit information about beam directions is not available. We present a beam direction discovery approach that utilizes beam pattern amplitudes and combines them with the phase information available for a quick estimate of the beam direction. Numerical results reveal a significant reduction of the pilot overhead by 42% and up to 62% compared to the state-of-the-art.

Il saggio cerca di ridare luce ad Anima nera, una commedia imperniata su una domanda: come trovare un equilibrio tra il rimpianto e il bisogno di voltare pagina, gettando alle spalle un passato macchiato da vizi e dissolutezza morale? Il presente studio prende in esame i diversi temi trattati nella pièce, evidenziando come nella commedia i temi dell’emarginazione e dell’alienazione sono contigui. Ci si concentra poi dettagliatamente sulle diverse sfaccettature del carattere del protagonista che simboleggia l’aspirazione alla purezza e alla normalità. Si cerca anche di mettere in luce come lo scrittore inserisce in Anima nerail contesto sociale degli anni ‘60, mostrando le conseguenze del degrado postbellico dell’Italia. L’analisi si concentra anche su alcuni aspetti innovativi della commedia, primo fra tutti il fatto che la commedia è strutturata in due tempi senza ripartizioni in scene, la presenza continua e simultanea di tutti i personaggi in scena, nonché l’intrecciarsi di due dialoghi contemporanei fra persone diverse il che crea la contemporaneità di due momenti.

Millimeter-wave transceivers use large antenna arrays to form narrow high-directional beams and overcome severe attenuation. Narrow beams require large signaling overhead to be aligned if no prior information about beam directions is available. Moreover, beams drift with time due to user mobility and may need to be realigned. Beam tracking is commonly used to keep the beams tightly coupled and eliminate the overhead associated with realignment. Hence, with periodic measurements, beams are adjusted before they lose alignment. We propose a model where the receiver adjusts beam direction “continuously” over each physical-layer sample according to a carefully calculated estimate of the continuous variation of the beams. In our approach, the change of direction is updated using the rate variation prediction of beam angles via three different solutions. Our approach incurs no additional overhead in pilots, yet, the performance of beam tracking is improved significantly. Numerical results reveal an SNR enhancement associated with reducing the MSE of the beam directions. In addition, our approach reduces the pilot overhead by 60% and up to 87% while achieving a similar total tracking duration as the state-of-the-art.

Table of Contents Abstract Introduction Patients and Methods Results Discussion Conclusion References Abstract Cholestasis includes retention of conjugated bilirubin, bile salts and other components of the bile. It is not [...]

A panel of clinician scientists with expertise in neuromuscular blockade (NMB) monitoring was convened with a charge to prepare a consensus statement on indications for and proper use of such monitors. The aims of this article are to: (a) provide the rationale and scientific basis for the use of quantitative NMB monitoring; (b) offer a set of recommendations for quantitative NMB monitoring standards; (c) specify educational goals; and (d) propose training recommendations to ensure proper neuromuscular monitoring and management. The panel believes that whenever a neuromuscular blocker is administered, neuromuscular function must be monitored by observing the evoked muscular response to peripheral nerve stimulation. Ideally, this should be done at the hand muscles (not the facial muscles) with a quantitative (objective) monitor. Objective monitoring (documentation of train-of-four ratio ≥0.90) is the only method of assuring that satisfactory recovery of neuromuscular function has taken place. The panel also recommends that subjective evaluation of the responses to train-of-four stimulation (when using a peripheral nerve stimulator) or clinical tests of recovery from NMB (such as the 5-second head lift) should be abandoned in favor of objective monitoring. During an interim period for establishing these recommendations, if only a peripheral nerve stimulator is available, its use should be mandatory in any patient receiving a neuromuscular blocking drug. The panel acknowledges that publishing this statement per se will not result in its spontaneous acceptance, adherence to its recommendations, or change in routine practice. Implementation of objective monitoring will likely require professional societies and anesthesia department leadership to champion its use to change anesthesia practitioner behavior.

Supplemental Digital Content is available in the text.Published ahead of print May 2, 2016

It has been hypothesized that providing deep neuromuscular block (a posttetanic count of 1 or more, but a train-of-four [TOF] count of zero) when compared with moderate block (TOF counts of 1–3) for laparoscopic surgery would allow for the use of lower inflation pressures while optimizing surgical space and enhancing patient safety. We conducted a literature search on 6 different medical databases using 3 search strategies in each database in an attempt to find data substantiating this proposition. In addition, we studied the reference lists of the articles retrieved in the search and of other relevant articles known to the authors. There is some evidence that maintaining low inflation pressures during intra-abdominal laparoscopic surgery may reduce postoperative pain. Unfortunately most of the studies that come to these conclusions give few if any details as to the anesthetic protocol or the management of neuromuscular block. Performing laparoscopic surgery under low versus standard pressure pneumoperitoneum is associated with no difference in outcome with respect to surgical morbidity, conversion to open cholecystectomy, hemodynamic effects, length of hospital stay, or patient satisfaction. There is a limit to what deep neuromuscular block can achieve. Attempts to perform laparoscopic cholecystectomy at an inflation pressure of 8 mm Hg are associated with a 40% failure rate even at posttetanic counts of 1 or less. Well-designed studies that ask the question “is deep block superior to moderate block vis-à-vis surgical operating conditions” are essentially nonexistent. Without exception, all the peer-reviewed studies we uncovered which state that they investigated this issue have such serious flaws in their protocols that the authors’ conclusions are suspect. However, there is evidence that abdominal compliance was not increased by a significant amount when deep block was established when compared with moderate neuromuscular block. Maintenance of deep block for the duration of the pneumoperitoneum presents a problem for clinicians who do not have access to sugammadex. Reversal of block with neostigmine at a time when no response to TOF stimulation can be elicited is slow and incomplete and increases the potential for postoperative residual neuromuscular block. The obligatory addition of sugammadex to any anesthetic protocol based on the continuous maintenance of deep block is not without associated caveats. First, monitoring of neuromuscular function is still essential and second, antagonism of deep block necessitates doses of sugammadex of ≥4.0 mg/kg. Thus, maintenance of deep block has substantial economic repercussions. There are little objective data to support the proposition that deep neuromuscular block (when compared with less intense block; TOF counts of 1–3) contributes to better patient outcome or improves surgical operating conditions.

Epigenetics dictate how the genetic blueprint is ultimately expressed and, therefore, is fundamental to our understanding of disease etiology and cellular responses and consequences to exposure of stimuli, such as anesthetics and perioperative stress. The goal of this review is to provide a concise overview of the fundamental concepts in epigenetics and discuss how epigenetics may be incorporated into research studies in anesthesiology.

We review the efficacy and safety of gantacurium and AV002, two novel, investigational fumarate-based nondepolarizing neuromuscular blockers, as well as sugammadex and cysteine, two novel reversal drugs that have no acetylcholinesterase inhibition properties.

Sugammadex, a modified -cyclodextrin, is the first selective relaxant binding agent. Sugammadex forms very tight complexes in a 1:1 ratio with steroidal neuromuscular blocking agents (rocuronium > vecuronium >> pancuronium). This guest–host complex, which exists in equilibrium, is stable because of its very high association rate and very low dissociation rate. Sugammadex has no effect on acetylcholinesterases or on any receptor system in the body, eliminating the need for anticholinergic drugs, which have undesirable adverse effects. Phase I–III trials found that sugammadex can antagonize any level of neuromuscular blockade, including the profound blockade induced by rocuronium, adding flexibility to the use of nondepolarizing relaxants. Sugammadex rapidly clears from most organs. Sugammadex in doses ranging from 2 to 16 mg/kg is recommended, depending of the level of rocuronium- or vecuronium-induced blockade. Common (incidence of 1–10%) adverse effects are similar for sugammadex and placebo, and include anesthetic complications (movement, coughing, grimacing or suckling on the tracheal tube) and cough. The US FDA has had concerns regarding the safety of sugammadex (hypersensitivity and allergic reactions), but upcoming international studies and the drugs widespread use in the EU will provide additional information.

Purpose: To evaluate the metabolic, hormonal and gastric fluid and pH changes after administration of a small volume of different preoperative feeding regimens.

This work develops efficient algorithms for numerically solving the neutron diffusion equation by a wavelet Galerkin method (WGM). One of the main problems encountered in solving neutron diffusion equation using WGM is the treatment of the boundary and interface conditions. In one-dimensional problems, the boundaries of the wavelet series expansions are assumed to be the analytical boundaries of the problem, and the boundary condition equations are replaced by end equations in Galerkin system. In two-dimensional problems, in order to maintain the integrity of the system, the boundaries of the wavelet series are shifted until the end is independent on any expansion coefficients of the scaling function that affect the solution within the real boundaries.Since the scaling functions are compactly supported, only a finite number of the connection coefficients are nonzero. The resultant matrix has a block diagonal structure, which can be inverted easily, therefore, enables us to extend the solution to two-dimensional heterogeneous cases and make the inner iteration efficient in the eigenvalue and multigroup problems. We tested our WGM algorithm with several diffusion problems including two-dimensional heterogeneous problems and multi-group problems. The solutions are very accurate with a proper selection of Daubechies' order and dilation order. Our WGM algorithm provides very accurate solutions for one-dimensional and two-dimensional heterogeneous problems in which the flux exhibits very steep gradients.

Purpose:To study the dose-response relationships for neostigmine and edrophonium during antagonism of neuromuscular block induced by atracurium and cisatracurium.

Purpose:To evaluate the effects of tramadol administration at wound closure on postoperative pain and analgesic requirements in patients undergoing laparoscopic cholecystectomy.

Purpose: To identify the variables most useful in predicting difficult laryngoscopy and intubation from various clinical, skeletal (lateral x-rays) and soft tissue (three-dimensional computed tomography imaging) measurements. Methods: Twenty-four adult patients in whom an unanticipated difficult trachéal intubation was identified according to established criteria were evaluated. Further, a control group of 32 patients in whom trachéal intubation was easily accomplished was studied. We applied murtivariate discriminant analysis to clinical and radiological data of all patients to select those variables most useful in predicting difficult laryngoscopy and intubation. The receiver operating characteristic (ROC) curve was used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model. Results: With the clinical data alone, discriminant analysis identified four risk factors that correlated with the prediction of difficult laryngoscopy and intubation: thyrosternal distance, thyromental distance, neck circumference and Mallampati classification. With both clinical and radiological data, discriminant analysis identified five risk factors: thyrosternal distance, thyromental distance, Mallampati classification, depth of spine C2 and angle A (the most antero-inferior point of the upper central incisor tooth). The positive predictive value of this combined (clinical and radiological) model was greater than that of the clinical model alone (95.8%vs87.5%, respectively). The areas under the ROC curves, that measure the probability of the correct prediction of the clinical and the combined models, were found to be 0.933 and 0.973, respectively. Conclusions: These models can be used for predicting difficult laryngoscopy and intubation in clinical practice.

Twenty-three patients undergoing surgery below T.6 dermatome were anaesthetized with epidural morphine 20 mg in 15 ml of saline, thiopentone drip 0·04–0·1 mg/kg/min. and pancuronium 0·1 mg/kg. The patients had satisfactory analgesia intra-operatively. Post-operative analgesia lasted for varying periods ranging from 13 hours to 24 hours and above. The cardiovascular system was stable. Post-epidural morphine complications of respiratory depression (three patients), urinary retention (one patient) and pruritus (one patient) were seen and they were managed successfully.

Purpose: To compare the efficacy of tramadol and morphine for intra-and postoperative analgesia in patients undergoing laparoscopic cholecystectomy. Methods: In a prospective, randomized, double-blind study 100 patients were allocated randomly into two groups. Ten minutes before induction of anaesthesia, patients in group I received 100 mg tramadol and those in group 2 received 10 mg morphineiv. Anaesthesia was induced with 5 mg·kg−1thiopental and was maintained with O2, N2O plus isoflurane with additional doses of tramadol or morphine as decided by the attending anaesthetist. Postoperatively, patients in group I and group 2 received tramadol and morphine, respectively, from a patient-controlled analgesia (PCA) device. Pain, analgesic consumption, vital signs and side effects were recorded postoperatively for 24 hr. Results: Intraoperative consumption of tramadol and morphine were 137 ± 37 and 12.2 ± 3 mg, respectively. Compared with morphine, patients receiving tramadol had higher blood pressures and required greater mean ETisoto control haemodynamic variables (P< 0.05). Postoperatively, there were no differences in observer pain score or visual analogue pain score during the first 24 hr between groups except at 30, 45, and 90 min where patients in the tramadol group reported higher pain scores (P< 0.05). The cumulative, 24 hr PCA consumption was III ± 93 and 7.5 ± 6.6 mg of tramadol and morphine, respectively. Conclusions: There was no difference between the use of tramadol and morphine to treat pain after laparoscopic cholecystectomy from 90 min after the end of surgery. Morphine was more effective than tramadol as an intraoperative analgesic.

Purpose: We studied the neuromuscular effects of both atracurium and mivacurium in a patient with Charcot-Marie-Tooth disease (CMTD) during nitrous oxide-oxygen-alfentanil-propofol anaesthesia. Neuromuscular blockade was monitored electromyographically. Train-of-four stimulation (2Hz @ 20 sec intervals) was delivered to the ulnar nerve throughout the period of observation. Clinical features: A 17-yr-old man with the diagnosis of CMTD was presented twice for two different orthopaedic surgical procedures. The CMTD had been diagnosed since childhood. Neurological examination revealed distal wasting of the upper and lower limbs, generalised absence of reflexes and decreased sensation in a stocking distribution. In both anaesthetics, induction was carried out with alfentanil and propofol, and anaesthesia was maintained with nitrous oxide in oxygen, alfentanil and propofol infusion. The patient demonstrated a normal response to both atracurium and mivacurium. Onset time and the maximum block attained after atracurium and mivacurium were 240 and 210 sec, and 97% and 99% inhibition of T1 (the first twitch of TOF stimulation), respectively. Recovery of T1 to 10% of the control value occurred 30 and 11.5 min after the administration of atracurium and mivacurium, respectively. The patient made uneventful recoveries after both anaesthetics. Conclusion: There was no evidence of prolonged response to atracurium and mivacurium in our patient with CMTD.

The dose—response relationship and the doses of atropine required to prevent neostigminefrom lowering heart rates below baseline in 50 per cent (ED50) and 95 per cent (ED95) of patients after antagonism of pancuronium-induced neuromuscular blockade were determined in 70 patients with neostigmine-atropine mixtures. Neostigmine 0.04 mg · kg−1(group A, n = 35) or 0.06mg · kg−1(group B, n = 35) was randomly mixed with one of seven doses of atropine (ranging from 0.014 to 0.04mg · kg−1) in group A and from 0.02 to 0.04 mg · kg−1in group B), with dose-response curves for atropine being constructed for both groups 5 and 10 min after injection of the mixture. These dose-response curves were found to be parallel in both groups. The calculated ED50 and ED95 values of atropine were similar in both groups. The estimated ED 50 doses of atropine in groups A and B at 5 min were 0.031 and 0.033 mg · kg−1respectively, and at 10 min the ED50 doses were 0.037 and 0.037 mg · kg−1respectively. The calculated ED95 doses of atropine in groups A and B at 5 min were 0.05 and 0.046 mg · kg−1, and at 10 min the ED95 doses were also similar, being 0.06 and 0.055 mg · kg−1respectively. Under the conditions employed in this study it would seem that in order to prevent late reductions in heart rates, the appropriate doses of atropine when used with neostigmine should be greater than that commonly used.

This study was designed to investigate the effect of different priming doses of edrophonium on the relationship between the the recovery of the first twitch of the train-of-four (T1) and train-of-four (TOF) ratio. This relationship was studied after the administration of the full dose of the antagonist in all groups. Edrophonium 1.0 mg-kg-1was administered either in a single bolus dose (Group I, controls) or in an initial dose of 0.05, 0.1, 0.15 or 0.2 mg·kg-1followed one minute later by the remainder of the 1.0 mg·kg-1dose in Groups II to V. Reversal was attempted at the ten per cent spontaneous recovery of twitch height (T1) from atracurium-induced neuromuscular blockade. Of all the groups studied. Group V had a significantly greater recovery in the TOF ratio at any given T1 value. When first twitch tension (T1) had recovered to 100 per cent of the control, it was found for the same tension that the TOF ratio was greater in Group V, being 0.75 compared to 0.63, 0.65, 0.65 and 0.64 in Groups I to IV respectively. The implication is that this differential ability to reverse fade (or prejunctional activity) may be involved in the acceleration of recovery.

A 22-year-old athlete was scheduled for a minor surgical procedure under general anaesthesia. During anaesthesia, his electrocardiogram demonstrated multiple episodes of dysrhythmias including complete bundle branch block, atrioventricular (AV) block, isorhythmic atrioventricular dissociation with junctional rhythm. Administration of atropine 1.0 mg IV terminated the last episode of dysrhythmias. Postoperatively, a resting 12-lead electrocardiogram showed first degree AV block, ST-segment elevation and prominent U waves. A 24 hour Holter recording demonstrated first degree atrioventricular block, episodes of marked sinus arrhythmias and one episode of sinus tachycardia at a rate of 152 beats ·min-1. Treadmill stress testing revealed peak achieved heart rate of 200 beats·min-1without ischaemia. These findings collectively indicated athletic heart syndrome. Implications of athletic heart syndrome for the anaesthetist are reviewed and discussed.

To determine the optimal priming dose for administration in divided doses, atracurium was given to 77 patients either in a single dose of 0.5 mg·kg-11 or in an initial dose of 0.04, 0.05, 0.06, 0.07, 0.08 or 0.09 mg·kg-1,. followed three minutes later by the remainder of the 0.5 mg·kg-1dose. Patients were anaesthetized throughout the study. When atracurium was given as a single bolus of 0.5 mg·kg-1, the mean time to complete neuromuscular block was 141.5 seconds. Administration in divided doses accelerated the onset time (p < 0.01), that is the time from the intubating dose to the complete suppression of train-of-four (TOF) response. The TOF ratio decreased slightly but statistically significantly following the priming doses. When the priming dose was 0.05 mg·kg-1, the mean onset time was 70.9 seconds and priming with larger doses did not add any further advantage. It is concluded that 0.05 mg·kg-11 appears to be the optimal priming dose for the administration of atracurium in divided doses. When0.05 mg·kg-1is given three minutes before the intubating dose, tracheal intubation can be accomplished in less than 90 seconds.

The hypothesis that administration of neostigmine in divided doses might accelerate the antagonism of neuromuscular blockade was investigated. Neostigmine 0.05 mg.kg-1was administered either in a single bolus dose (Group I, n = 16) or in an initial dose of 0.01 mg-kg-1followed three minutes later by 0.04 mg-kg-1(Group II, n = 16) for antagonism of atracurium-induced blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. The mean time (±SD)from the first injection of the drug until the train-of-four (TOFj ratio value had reached 0.75 was significantly shorter in Group II (p < 0.05) than in Group I (391.8 ± 83.3 and 468.6 ± 150.3 seconds respectively). The rate of TOF ratio recovery was 2.5 times faster after neostigmine administration in divided doses.

Anaesthesia for the repair of a large occipito cervical encephalomyelocele in a neonate with Kippel-Feil syndrome is described. The fusion of the cervical spines, a short neck, low posterior hair line and Sprengel’s deformity, which were present in this patient, collectively indicated Klippel-Feil syndrome. In addition to the usual stigmata of the syndrome, this patient had a large encephalomyelocele and persistant patent ductus arteriosus complicated by congestive heart failure. Patients with this syndrome are vulnerable to cervical spinal cord injury and are at high risk for neurological injury not only during laryngoscopy and intubation but thereafter. Implications of Kippel-Feil syndrome for the anaesthetist are reviewed and discussed.

Thirty-four patients of ASA physical status I or II scheduled for gall bladder surgery were studied in a comparative prospective trial to evaluate the efficacy of epidural and intramuscular ketamine for postoperative pain relief. They were divided randomly into three groups. Group I (II patients) received 30 mg intramuscular ketamine. Group II (10patients) and Group III (13 patients) received 10 and 30 mg ketamine in 10 ml saline respectively, through epidural catheters. Pain was evaluated every two hours for the first 24 hours post-operatively by using a linear analogue pain scale from 0–10. Ketamine was given on the patient’s request and whenever the pain score exceeded three. Ketamine produced analgesia in all patients studied. The reduction of pain score after two and four hours in Group I and III was significant when compared to Group II. Seven patients (54 per cent) in Group III did not require further analgesia after the initial injection. However, following 10 mg epidural ketamine or 30 mg IM ketamine, postoperative pain was more frequent. Four patients who received epidural ketamine complained of transient burning pain in the back during injection. No patient developed respiratory depression, psychic disturbance, cardiovascular instability, bladder dysfunction or neurologic deficit. It is concluded that 30 mg epidural ketamine is a safe and effective method for postoperative analgesia.

Atracurium is a new non-depolarising neuromuscular blocking agent, metabolized through Hofmann elimination. A case is presented in which a 45-year-old patient with severe liver disease showed a decreased response to atracurium. The possible causes of resistance to atracurium are discussed. We conclude that atracurium may be used in patients with severe hepatic disease.

Five male patients undergoing haemorrhoidectomy received. intrathecal meperidine 1 mg.kg-1as the sole anaesthetic agent. Plasma concentration-time profiles were investigated. The peak plasma concentration of meperidine was 175 ± 78.8 ng.ml-1(mean ±SD) and this occurred 90 minutes after intrathecal injection. The plasma concentrations generally were lower than those necessary for systemic analgesic effects. The terminal elimination half life of meperidine (f1/2β) in the plasma was 198 minutes.

determine the optimal interval between the administration of the priming dose and the intubating dose, atracurium was given to 44 patients either in a single dose of 0.5 mg.kg-1or in an initial dose of0.06mg.kg-1followed two, three or five minutes later with 0.44 mg.kg-1.

A comparison was made between atracurium and succinylcholine in 40 patients undergoing short gynaecological procedures of 30 minutes or less.

Purpose: Postoperative nausea and vomiting (PONV) is a distressing adverse effect of general anaesthesia. The aim of the current study was to compare the antiemetic activity of different 5-hydroxytryptamine3receptor antagonists with that of metoclopramide and placebo. Methods: In a prospective, randomized, double-blind study we have compared the antiemetic activity of the prophylactic administration of ondansetron 4 mg, tropisetron 5 mg and granisetron 3 mg with that of metoclopramide 10 mg and placebo in 132 patients undergoing laparoscopic cholecystectomy. All study drugs and placebo were given as a short iv infusion ten minutes before the induction of anaesthesia. Perioperative anaesthetic care was standardized in all patients. Nausea and vomiting were assessed by direct questioning of the patient at 1, 4, 9, 12, 18 and 24 hr after recovery from anaesthesia. If patients experienced nausea and/or vomiting, rescue antiemetic treatment (metoclopramide 10 mg iv) was administered. Results: For the 24-hr recovery period after surgery, the percentages of emesis-free patients were 65.5%, 52%, 48%, 29.2% and 27.6% in the ondansetron, granisetron, tropisetron, metoclopramide and placebo groups, respectively. Prophylactic antiemetic treatment with ondansetron resulted in a lower incidence (P = 0.02) of PONV than with metoclopramide or placebo. The times at which rescue antiemetic was first received were longer (P &lt; 0.01) in ondansetron group than in the placebo and metoclopramide groups. There were no statistical differences between ondansetron, tropisetron and granisetron groups. Conclusions: Ondansetron, when given prophylactically resulted in a significantly lower incidence of PONV than metoclopramide and placebo. Metoclopramide was ineffective.

Purpose: Following transsternal thymectomy, up to 50% of patients may require postoperative ventilation. The aim of this study was to identify the variables most useful in predicting the myasthenic patient who needs postoperative mechanical ventilation. Methods: We applied multivariate discriminant analysis to preoperative physical, historical, laboratory and intraoperative data of 51 myasthenic patients who underwent transcervical-transsternal thymectomy to select those variables most useful in predicting the postoperative need for mechanical ventilation. The receiver operating characteristic (ROC) curve was also used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model. Results: Discriminant analysis identified seven risk factors that correlated with the need for postoperative ventilation: FVC, FEF25–75%, MEF50%and their percentages of the predicted values, as well as, sex. The model correctly predicted the actual ventilatory outcome in 88.2% of patients. The area under the ROC curve verified that our model correctly predicted the actual ventilatory outcome with a probability of 88.2%. Conclusions: This model can be used for predicting the need for postoperative mechanical ventilation in myasthenia gravis patients.

In a randomized, double-blind study we have examined the analgesic efficacy of caudal administration of midazolam, bupivacaine, or a mixture of both drugs in 45 children, undergoing inguinal herniotomy. They were allocated randomly into three groups (n = 15 in each) to receive a caudal injection of either 0.25% bupivacaine 1 ml · kg−1with or without midazolam 50 μg · kg−1or midazolam 50 μg · kg−1with normal saline 1 ml · kg−1. There were no differences in quality of pain relief, postoperative behaviour or analgesic requirements between the midazolam group and the other two groups. Times to first analgesic administration (paracetamol suppositories) were longer (P < 0.001) in the bupivacaine-midazolam group than in the other two groups. Further, the bupivacaine-midazolam group received fewer (P < 0.05) doses of paracetamol than the bupivacaine group. Side effects such as motor weakness, respiratory depression or prolonged sedation were not observed in patients who received caudal epidural midazolam only. We conclude that caudal midazolam in a dose of 50 μg · kg−1provides equivalent analgesia to bupivacaine 0.25%, when administered postoperatively in a volume of 1 ml · kg−1for children following unilateral inguinal hemiotomy.

Different priming sequences of equipotent doses of rocuronium and mivacurium on the onset of maximum neuromuscular block and intubating conditions were compared with those obtained after succinylcholine. During thiopentone-fentanylnitrous oxide anaesthesia, 70 patients were randomly assigned into seven groups. Group I received mivacurium 0.15 mg · kg−1as a single bolus dose. Group II received a priming dose of mivacurium 0.015 mg · kg−1followed three minutes later by mivacurium 0.135 mg · kg−1. Group III received rocuronium 0.6 mg · kg−1as a single bolus dose, and Group IV received an initial dose of rocuronium 0.06 mg · kg−1followed by rocuronium 0.54 mg · kg−1. Group V received a priming dose of mivacurium 0.015 mg · kg−1followed by rocuronium 0.54 mg · kg−1. Group VI received an initial dose of rocuronium 0.06 mg · kg−1followed by mivacurium 0.135 mg · kg−1. Group VII received succinykholine 1.0 mg · kg−1. Groups I, III, and VII received a placebo injection before the administration of the neuromuscular blocking drug. Additional thiopentone 2 mg · kg−1iv was given 30 sec before intubation. Onset times (mean (95% confidence interval)) after priming a rocuronium block with either rocuronium (73 (57–90) sec) or mivacurium (58 (47–69) sec) were similar to those after succinykholine (54 (40–68) sec), and were shorter (P < 0.01) than that observed in other groups. Intubating conditions were not different between the groups. The duration of neuromuscular block was shortest with succinykholine. It is concluded that priming a rocuronium block with either mivacurium or rocuronium resulted in a neuromuscular block comparable to that of succinykholine in both the onset of action and intubating conditions.

Purpose: To determine whether central venous pressure at the common iliac vein reflects right atrial pressure in adult patients. Methods: In this prospective, non-blinded study 26 mechanically-ventilated adult patients were studied. Simultaneous pressure readings were obtained from the right atrium (TCVP) and the common iliac vein (ACVP). Results: There was a correlation between TCVP and ACVP (r = 0.987;P&lt; 0.0001). The mean difference between TCVP and ACVP was 0.93 mm Hg. And the limits of agreement were:-1.93 to 1.77 mm Hg. Conclusion: Venous pressure recorded from the common iliac vein reflects that in the right atrium. Adopting a femoral route for central venous pressure measurement may avoid some of the complications associated with the subclavian route.

This study was designed to investigate the effect of divided administration of edrophonium on the course of neuromuscular recovery from a pipecuronium neuromuscular blockade. During thiopentone-nitrous oxide-halothane anaesthesia 48 patients were given pipecuronium 70 μg · kg−1. Patients were randomly assigned to one of four groups (n = 12 in each) to receive either edrophonium 1 mg · kg−1(Groups I and II) or edrophonium 0.75 mg · kg−1(Groups III and IV). In Groups I and III (single-dose groups), edrophonium was administered as a single bolus dose. In Groups II and IV (divided-dose groups) edrophonium was administered as an initial dose of 0.25 mg · kg−1followed three minutes later by either 0.75 or 0.50 mg · kg−1respectively. Reversal was attempted at 20% spontaneous recovery of twitch height. Administration of edrophonium in divided doses (Groups II and IV) accelerated the reversal of the pipecuronium neuromuscular blockade. At ten minutes post-reversal, train-of-four (TOF) ratio recovery reached 0.75 or more in 12 (100%) and in ten (83%) patients in Groups II and IV respectively. Similarly, times to attain a TOF of 0.75 (SEM) were shorter in the divided-dose groups than in the single-dose groups (P < 0.05), being 354.5 (38.7) and 398.3 (49.1) sec in Groups II and IV vs 705.4 (66.6) and 651.2 (54.3) sec in Groups I and III respectively. Time was counted from the first administration of edrophonium. It is concluded that administration of edrophonium in divided doses produced a faster reversal of residual pipecuronium-induced neuromuscular blockade than single bolus administration. Also, administration in divided doses reduced the requirements of edrophonium needed for reversal of pipecuronium neuromuscular blockade.

Neostigmine 0.06 mg · kg−1or edrophonium 1 mg · kg−1were administered to two groups of 15 patients each for antagonism of pipecuronium-induced neuromuscular block at 20% spontaneous recovery of the first twitch (T1) of the train-of-four (TOF) stimulation. The mean onset of action (± SEM) of edrophonium (18.1 ± 2.4 sec) was significantly more rapid (P < 0.01) than that of neostigmine (47.6 ± 4 sec), as were the times taken to attain a TOF ratio of 0.25 and 0.5. Nevertheless, the reversal time (time taken from the end of injection of the antagonist until TOF ratio value had reached 0.75) was significantly shorter (P < 0.01) in the neostigmine than in the edrophonium group (499.3 ± 62 vs 767 ± 52 sec respectively). The TOF ratio ten minutes after reversal was greater in the neostigmine group than in the edrophonium group (P < 0.01), 0.78 ± 0.02 vs 0.68 ± 0.02 min respectively. At that time, 33% (5 out of 15) and 80% (12 out of 15) patients failed to be reversed adequately (TOF ratio of 0.75) after neostigmine 0.06 mg · kg−1and edrophonium 1 mg · kg−1, respectively. Administration of one additional dose (one-third of the initial dose) of the same antagonist resulted in adequate antagonism in the remaining five patients in the neostigmine group and in nine patients in the edrophonium group. Two such doses were required in the remaining three patients in the latter group. The mean total dose of neostigmine and edrophonium employed in this study was 0.067 ± 0.002 and 1.3 ± 0.05 mg · kg−1, respectively. Under the conditions of this study, edrophonium in a dose of 1 mg · kg−1did not consistently antagonize residual neuromuscular blockade induced by pipecuronium at 20% recovery of T1.

To evaluate the effect of dextran 70 on the kinetics of epidural meperidine, 10 female patients anesthetized with nitrous oxide and halothane were studied. Meperidine, 1 mg· kg−1, was administered epidurally in either 10 ml dextran 70 in saline solution (group I) or 10 ml saline solution (group II, control subjects). Plasma concentration of meperidine was determined for 10 hours after its administration with GC. Meperidine plasma concentration-time curves could be best resolved into three exponential terms with a lag time in both groups of patients. The disposition kinetics were described adequately by a three-compartment model. This study demonstrated that apart from a significantly longer lag time and smaller k10(apparent first-order rate constant for elimination of meperidine from the central compartment), the addition of dextran did not alter significantly the kinetic parameters of epidural meperidine.

A 28-year-old male patient developed bilateral hydrothorax due to extravasation of fluid into the mediastinum from a subclavian line. The injection of radio-opaque dye through the central venous cannula confirmed spillage into the mediastinum. There was no direct communication between the central venous cannula and the pleural cavities. The hydrothorax appeared to develop as a result of a shift of fluid from the mediastinum into the pleuracavities due to pressure differences in the two compartments. Bilateral chest tubes were inserted, the subclavian cannula was removed and the patient made a good recovery.