bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogenous Spatial Attention Influences Figure-Ground Assignment
Authors: Vecera Shaun P. , Flevaris Anastasia V. , Filapek Joseph C.
Published: January 2004

In a hierarchical stage account of vision, figure-ground assignment is thought to be completed before the operation of focal spatial attention. Results of previous studies have supported this account by showing that unpredictive, exogenous spatial precues do not influence figure-ground assignment, although voluntary attention can influence figure-ground assignment. However, in these studies, attention was not summoned directly to a region in a figure-ground display. In three experiments, we addressed the relationship between figure-ground assignment and visuospatial attention. In Experiment 1, we replicated the finding that exogenous precues do not influence figure-ground assignment when they direct attention outside of a figure-ground stimulus. In Experiment 2, we demonstrated that exogenous attention can influence figure-ground assignment if it is directed to one of the regions in a figure-ground stimulus. In Experiment 3, we demonstrated that exogenous attention can influence figure-ground assignment in displays that contain a Gestalt figure-ground cue; this result suggests that figure-ground processes are not entirely completed prior to the operation of focal spatial attention. Exogenous spatial attention acts as a cue for figure-ground assignment and can affect the outcome of figure-ground processes.
Visual Sensing Without Seeing
Authors: Rensink Ronald A.
Published: January 2004

It has often been assumed that when we use vision to become aware of an object or event in our surroundings, this must be accompanied by a corresponding visual experience (i.e., seeing). The studies reported here show that this assumption is incorrect. When observers view a sequence of displays alternating between an image of a scene and the same image changed in some way, they often feel (or sense) the change even though they have no visual experience of it. The subjective difference between sensing and seeing is mirrored in several behavioral differences, suggesting that these are two distinct modes of conscious visual perception.
Lightness Constancy in the Presence of Specular Highlights
Authors: Todd James T. , Norman J. Farley , Mingolla Ennio
Published: January 2004

Visible surfaces in a natural environment often have multiple components of reflectance, including a diffuse component, by which light is scattered isotropically in all possible directions, and a specular component, by which light is reflected anisotropically within a limited range of directions. The research described in the present article was designed to investigate how these different components of reflectance influence the perception of lightness. Human observers were presented with shaded images of smoothly curved surfaces and asked to compare the relative lightness of different surface regions whose diffuse and specular components of luminance were independently manipulated. The results revealed that observers are able to discount the presence of specular highlights so that the relative lightness among different regions is determined almost entirely by the diffuse component of surface reflectance.
The Perception of Doubly Curved Surfaces From Anisotropic Textures
Authors: Todd James T. , Oomes Augustinus H.J. , Koenderink Jan J. , Kappers Astrid M.L.
Published: January 2004

Most existing computational models of the visual perception of three-dimensional shape from texture are based on assumed constraints about how texture is distributed on visible surfaces. The research described in the present article was designed to investigate how violations of these assumptions influence human perception. Observers were presented with images of smoothly curved surfaces depicted with different types of texture, whose distribution of surface markings could be both anisotropic and inhomogeneous. Observers judged the pattern of ordinal depth on each object by marking local maxima and minima along designated scan lines. They also judged the apparent magnitudes of relative depth between designated probe points on the surface. The results revealed a high degree of accuracy and reliability in all conditions, except for a systematic underestimation of the overall magnitude of surface relief. These findings suggest that human perception of three-dimensional shape from texture is much more robust than would be reasonable to expect based on current computational models of this phenomenon.
The New and Improved Two-Sample t Test
Authors: Keselman H.J. , Othman Abdul R. , Wilcox Rand R. , Fradette Katherine
Published: January 2004

This article considers the problem of comparing two independent groups in terms of some measure of location. It is well known that with Student's two-independent-sample t test, the actual level of significance can be well above or below the nominal level, confidence intervals can have inaccurate probability coverage, and power can be low relative to other methods. A solution to deal with heterogeneity is Welch's (1938) test. Welch's test deals with heteroscedasticity but can have poor power under arbitrarily small departures from normality. Yuen (1974) generalized Welch's test to trimmed means; her method provides improved control over the probability of a Type I error, but problems remain. Transformations for skewness improve matters, but the probability of a Type I error remains unsatisfactory in some situations. We find that a transformation for skewness combined with a bootstrap method improves Type I error control and probability coverage even if sample sizes are small.
The Basic-Level Convergence Effect in Memory Distortions
Authors: Pansky Ainat , Koriat Asher
Published: January 2004

Whereas most previous findings suggest that memory may become more abstract over time, so that memory for gist outlasts verbatim memory, there are findings suggesting that abstract information may sometimes be instantiated in more specific terms. In this study, we examined the hypothesis that retained information tends to converge at an intermediate level of abstractness—the basic level. In two experiments, we found bidirectional, symmetrical shifts in the memory for story material: Participants presented with either subordinate terms (e.g., sports car) or superordinate terms (e.g., vehicle) tended to falsely report basic-level terms (e.g., car) instead. This pattern emerged for both recall and recognition memory tests, at both immediate and delayed testing, and under free and forced reporting. The results suggest that the basic level, which has been considered cognitively optimal for perception, categorization, and communication, is also the preferred level for retaining episodic information in memory.
Hearing Cheats Touch, but Less in Congenitally Blind Than in Sighted Individuals
Authors: Hötting Kirsten , Röder Brigitte
Published: January 2004

The principles of cross-modal integration were investigated with an auditory-tactile illusion in sighted and con-genitally blind adults. Participants had to judge the number of rapidly presented tactile stimuli, which were presented together with task-irrelevant sounds. When one tactile stimulus was accompanied by more than one tone, participants reported perceiving more than a single touch. This illusion was more pronounced in sighted than congenitally blind participants. Given that the congenitally blind were more precise in judging the number of tactile stimuli in a control condition without tones, the present data are in accordance with a modality-appropriateness account suggesting that interference by a task-irrelevant modality is reduced if processing accuracy of the task-relevant modality is high.
No Blindness for Things that Do Not Change
Authors: Theeuwes Jan
Published: January 2004

It is well known that under normal circumstances, human observers are able to detect a visual change (a luminance transient) in the outside world very easily. This study demonstrated that observers are also easily able to detect a non-changing element if it is located in a display containing multiple elements that do change. That is, a nonchanging element popped out from a display containing multiple changing elements (luminance transients). The efficient detection of the nonchanging element may be due to temporal grouping created by the dynamic character of the stimulus display.
Mimicry and Prosocial Behavior
Authors: van Baaren Rick B. , Holland Rob W. , Kawakami Kerry , van Knippenberg Ad
Published: January 2004

Recent studies have shown that mimicry occurs unintentionally and even among strangers. In the present studies, we investigated the consequences of this automatic phenomenon in order to learn more about the adaptive function it serves. In three studies, we consistently found that mimicry increases pro-social behavior. Participants who had been mimicked were more helpful and generous toward other people than were non-mimicked participants. These beneficial consequences of mimicry were not restricted to behavior directed toward the mimicker, but included behavior directed toward people not directly involved in the mimicry situation. These results suggest that the effects of mimicry are not simply due to increased liking for the mimicker, but are due to increased prosocial orientation in general.
A non‐rebreathing coaxial anaesthesia system: dependence of end‐tidal gas concentrations on fresh gas flow and tidal volume
Authors: Tweed W. A.
Published: January 2004

A non‐rebreathing adaptation of the Bain coaxial anaesthesia circuit was developed in Nepal as a simple and economical anaesthetic system for underdeveloped countries. It was made by inserting a coaxial (Bain) tubing between an Ambu‐E valve and an Ambu self‐inflating bag. The present study examined the dependence of end‐tidal gas concentrations on fresh gas flow and tidal volume during halothane/oxygen/air inhalation anaesthesia. Four levels of fresh gas flow with normocapnia (0.2–3 l.min−1) and three levels of tidal volume at a constant respiratory rate of 15 breath.min−1 (to achieve end‐tidal carbon dioxide values of 4 ± 0.5%, 5 ± 0.5% and 6 ± 0.5%) were introduced in random order. Twelve ASA class 1 and 2 adult patients having intra‐abdominal or pelvic surgery were studied. With increasing fresh gas flow rates, there were proportionate increases in the end‐tidal concentrations of oxygen and halothane; with decreasing tidal volume and therefore less air dilution, there were proportionate increases in the end‐tidal concentrations of carbon dioxide, oxygen and halothane. Both effects were statistically and clinically significant. Thus, when this system is used as described, the end‐tidal concentrations of oxygen and halothane are highly dependent upon both the fresh gas flow and the tidal volume.
Neurotoxicity after spinal anaesthesia induced by serial intrathecal injections of magnesium sulphate  An experimental study in a rat model
Authors: Chanimov M. , Cohen M. L. , Grinspun Y. , Herbert M. , Reif R. , Kaufman I. , Bahar M.
Published: January 2004

We have previously demonstrated in a rat model that the lumbar intrathecal injection of 0.02 ml 6.3% magnesium sulphate, a concentration iso‐osmolar with rat plasma, produces a state of spinal anaesthesia and general sedation which reversed completely after 6 h, without evidence of neurotoxicity, immediately or during the week thereafter. Using the same model and five groups of six animals in each, we administered the same volume and concentration of magnesium sulphate and compared its clinical effects with those of 0.02 ml 12.6% magnesium sulphate, 0.02 ml 2% lignocaine and 0.02 ml 0.9% sodium chloride solution, given as a series of 15 injections on alternate days for a period of 1 month. The animals were then killed and their spinal cords and meninges examined histologically. No significant differences were noted in the times of onset, durations of sensory and motor blockade and the times to full recovery throughout the entire period of 1 month’s observation in the animals receiving intrathecal 6.3% magnesium sulphate. In the group receiving 12.6% magnesium sulphate, the time of onset of sensory and motor blockade was shorter and the duration of both parameters was significantly longer than in the former group. Full clinical recovery and resumption of normal eating and drinking took place in both groups throughout the entire series of 15 successive intrathecal injections. Identical, mild, uniform histopathological changes in the spinal cord were seen in all the five groups, including the group in which only the intrathecal catheter was implanted. The complete recovery and benign consequences of repeated intrathecal injections of iso‐osmolar magnesium sulphate in a rat model indicate a lack of neurotoxicity and provide an impetus for further trials in larger animal species, before initial clinical trials of this substance, given intrathecally, in humans.
Flow dynamics through spinal needles
Authors: Serpell M. G. , Gray W. M.
Published: January 2004

We examined the flow pattern produced when liquid dye was actively injected into a fluid medium at various flows through five different commonly used spinal needles. At all flows, the Whitacre‐type needles produced a directional stream exiting at an angle from the longitudinal axis. At intermediate rates the stream developed tracks which disappeared at faster rates. The Quincke needle always produced an undeviated stream of dye and did not form tracks at any flow rate. When a perspex plate (representing the spinal cord) was interposed in front of the needle, the dispersion of dye was always unidirectional from the Whitacre needle and bidirectional from the Quincke needle. The dye adhered to the surface of the plate as a concentrated film at slow rates and at faster rates it dispersed turbulently for both types of needle.
Occupational exposure to sevoflurane, halothane and nitrous oxide during paediatric anaesthesia  Waste gas exposure during paediatric anaesthesia
Authors: Hoerauf K. , Funk W. , Harth M. , Hobbhahn J.
Published: January 2004

We report the findings of a study on exposure of operating room staff to sevoflurane, halothane and nitrous oxide during induction and maintenance of anaesthesia in children. Concentrations of anaesthetic agents in the operating theatre were measured directly by highly sensitive, photoacoustic infrared spectrometer during 20 anaesthetics. Samples were taken from the breathing zones of the anaesthetist and the circulating nurse. The operating theatre was of modern design with an air conditioning system providing 20 changes of air each hour. The threshold values of 100 ppm N2O, 50 ppm isoflurane and 10 ppm halothane recommended by the United Kingdom Committee for Occupational Safety and Health (COSH) were exceeded in several cases for a short time during mask induction. After tracheal intubation, trace concentrations of sevoflurane, halothane and N2O were mostly under the recommended levels and comparable to levels measured during adult anaesthesia.
Changes in quality of life after intensive care: comparison with normal data
Authors: Ridley S. A. , Chrispin P. S. , Scotton H. , Rogers J. , Lloyd D.
Published: January 2004

The Short Form 36 was used to compare critically ill patients’ premorbid quality of life with normal values and investigate any changes following 6 months convalescence. One hundred and sixty‐six survivors completed the Short Form 36 at discharge from intensive care. The answers given by survivors were significantly lower than normal for all dimensions. However, 21 patients who suffered from acute life‐threatening conditions were identified and their overall scores were similar to normal values. After 6 months, 95 questionnaires were returned. Patients who had suffered acute pathologies reported significant decreases in quality of life whilst other patients with pre‐existing ill health reported significant improvement with reduced pain and better mental health, vitality and social function. This study suggests that quality of life of most patients admitted to intensive care is not as good as in the normal population but does not deteriorate except for those patients admitted after acute life‐threatening events.
Can ASA grade or Goldman's cardiac risk index predict peri‐operative mortality? A study of 16 227 patients
Authors: Prause G. , Ratzenhofer‐Comenda B. , Pierer G. , Smolle‐Ju¨ttner F. , Glanzer H. , Smolle J.
Published: January 2004

This trial was designed to study the correlation between peri‐operative mortality in patients undergoing elective surgery and the physical status classification of the American Society of Anesthesiologists, the Goldman multifactorial cardiac risk index or the two indices combined. All patients scheduled for elective surgery over a 5‐year period were evaluated pre‐operatively and were scored according to both indices. Of 16 227 patients studied, 215 died within 4 weeks of operation. Both indices correlated significantly with peri‐operative mortality, the ASA grade showing a closer correlation. A regression tree analysis divided the combination groups into five subgroups where the mortality was lowest (0.4%) in ASA grade ≤2 and cardiac risk index group I (score 0–5 points) and increased up to 7.3% in ASA grade = 4 and cardiac risk index group ≥3 (score >13 points). We conclude that for this large number of patients peri‐operative mortality can be predicted with the ASA grade and, to a lesser degree, with the cardiac risk index. Applied in the correct way, the combination of the two scores can increase the accuracy of prediction of peri‐operative mortality.
SCOTI vs. Wee An assessment of two oesophageal intubation detection devices
Authors: Lockey D. J. , Woodward W.
Published: January 2004

The SCOTI (Sonomatic Confirmation of Tracheal Intubation) is a newly marketed electronic device that relies on recognition of a resonating frequency for detection of tracheal intubation. It was compared with the modified Wee oesophageal intubation detection device, which works on a mechanical principle, in 50 elective surgical patients. All had simultaneous tracheal and oesophageal intubations. The Wee device correctly detected oesophageal and tracheal placement of the tracheal tube in all 50 patients. The SCOTI device incorrectly identified 1 of 50 tracheal intubations and was unable to identify the position of another. It correctly identified all 50 oesophageal intubations. The SCOTI is no better than the simple, cheap and reliable Wee device.
Single‐breath inhalation induction of sevoflurane anaesthesia with and without nitrous oxide: a feasibility study in adults and comparison with an intravenous bolus of propofol
Authors: Hall J. E. , Stewart J. I. M. , Harmer M.
Published: January 2004

The induction characteristics of sevoflurane in nitrous oxide and oxygen were compared with sevoflurane in oxygen alone and a propofol infusion. A vital capacity technique was used for the gaseous induction groups using a Mapleson A system and a 4‐litre reservoir bag. Four end‐points of anaesthesia were recorded: time to cessation of finger tapping, time to loss of eyelash reflex, time to jaw relaxation and time to regular settled breathing after laryngeal mask airway insertion. We also recorded sequential blood pressure and pulse rate, the incidence of adverse airway events and the acceptability of the induction technique. Propofol had a faster time to cessation of finger tapping (p <0.05) and jaw relaxation (p <0.01). These differences disappeared with the final induction stage and sevoflurane in nitrous oxide and oxygen had the faster time to regular settled breathing, though this did not reach statistical significance. Cardiovascular stability was good and comparable in all groups. There were few adverse airway events in any group and none caused oxygen saturation to fall below 96%. There was more excitation in the gaseous induction groups, though this did not interfere with induction. Patient satisfaction with induction was high.
Efficacy of ondansetron and metoclopramide for preventing postoperative emesis following strabismus surgery in children
Authors: Shende D. , Mandal N. G.
Published: January 2004

A double‐blind, randomised, placebo‐controlled trial was conducted to compare the efficacy of metoclopramide with the 5‐HT3 antagonist, ondansetron, for the prevention of postoperative emesis in children undergoing elective strabismus surgery. None of the children received any premedication and a similar anaesthetic technique was used for all. Ondansetron 0.15 mg.kg−1, metoclopramide 0.25 mg.kg−1 or saline placebo were administered following intravenous catheter placement. Episodes of emesis were recorded for the first 24 h for the intervals of 0–2, 2–6 and 6–24 h. The incidence of emesis in the first 24 h was observed to be 71.7% in the placebo group, 34.4% in the ondansetron group (p < 0.001) and 61.4% in the metoclopramide group (p = NS). The severity of vomiting was less in the ondansetron group as compared with metoclopramide (p < 0.01) and placebo (p < 0.001). Recovery room scores were comparable in all the groups. No serious side‐effects were observed in the ondansetron group. We conclude that prophylactic ondansetron is effective and superior to metoclopramide in the prevention of postoperative emesis in children following elective strabismus surgery.
Cardiopulmonary resuscitation: a retrospective review
Authors: Denton R. , Thomas A. N.
Published: January 2004

The outcome of patients admitted to intensive care after a cardiac arrest was determined by reviewing intensive care unit records at four hospitals for 1993 and 1994. Of the 112 patients identified, 49 survived intensive care of whom 28 were discharged from hospital. In January 1996, 26 of the 28 patients could be traced; 22 of these were still alive. Seven factors were significantly different between survivors and nonsurvivors. At the cardiac arrest these were the number of direct current shocks (p < 0.05) and adrenaline doses (p < 0.01) given. In intensive care the factors were the presence of reactive pupils (p < 0.01), Glasgow Coma Score (p < 0.001), APACHE II score (p < 0.05), arterial standard bicarbonate (p < 0.05) and the use of inotropes (p < 0.05). It was not possible to use individual variables to predict outcome at the time of intensive care unit admission. The results suggest that neurological function is an important determinant of outcome and more sensitive neurophysiological testing might be a useful prognostic tool.
Uterine rupture and epidural analgesia during trial of labour
Authors: Rowbottom S. J. , Critchley L. A. H. , Gin T.
Published: January 2004

A case of complete uterine rupture during a trial of labour in which epidural analgesia was used is described. The pain of uterine rupture was not masked by the addition of fentanyl 25 μg to bupivacaine 0.25% 6 ml but was relieved by bupivacaine 0.375% 6 ml.
Plasmapheresis in neuroleptic malignant syndrome
Authors: Gaitini L. , Fradis M. , Vaida S. , Krimerman S. , Beny A.
Published: January 2004

Neuroleptic malignant syndrome is a severe and potentially fatal reaction to neuroleptic drugs. Treatment requires withdrawal of the neuroleptic agent, metabolic and cardiovascular support, physical cooling and treatment with dantrolene sodium and bromcriptine mesylate. We report a therapeutic success of plasmapheresis in a case of neuroleptic malignant syndrome in which conventional therapy had failed. We postulate that plasmapheresis may prove to be a useful tool in treating this frequently fatal disease.
An evaluation of the SCOTI device
Authors: Haridas R. P. , Chesshire N. J. , Rocke D. A.
Published: January 2004

The Sonomatic Confirmation of Tracheal Intubation (SCOTI, Penlon, UK) device was evaluated in the laboratory with cut and uncut tracheal tubes and in 50 adult patients who underwent tracheal and oesophageal intubation with uncut tracheal tubes. We could not configure the SCOTI reliably with cut tracheal tubes. In the clinical study using uncut tubes the SCOTI identified all oesophageal intubations, but was only able to identify 84% (95% CI: 73.8–94.2%) of tracheal intubations. We recommend caution in using this device and further independent evaluation to determine its reliability.
Reduced cerebral vasomotor reactivity as an indicator of postoperative confusion
Authors: Kessler C. , Junge H. M. , Walker M. L. , Busack R. , Albrecht D. M. , Ackeren K. v.
Published: January 2004

Surgical intervention in elderly patients carries a high risk. A frequent problem with surgery in these patients is the occurrence of a temporary confusional state, which increases both the risk of postoperative complications and the need for intensive care. We hypothesised that, in part, temporary confusional state results from cerebral hypoxia occurring in response to blood pressure fluctuations during surgery. To assess whether disruption of autoregulation of cerebral blood vessels plays a role in temporary confusional state, we studied 31 patients over 55 years of age, using the Doppler–carbon dioxide test. We determined whether vasomotor reactivity could be used diagnostically to identify those patients most likely to experience temporary confusional state. Blood flow velocity in the middle cerebral artery was detected using Doppler ultrasound, and hypercapnia was induced by breathing carbon dioxide until an end‐tidal concentration of 8.0% by volume was reached. Vasomotor reactivity was calculated on the basis of the changes in blood flow velocity in response to the increase in carbon dioxide. Temporary confusional state was assessed using the Syndrome Short Test (Syndrom‐Kurztest). We found that resting blood flow velocity was inversely related to age (p < 0.05). In addition, there was a significant inverse correlation between vasomotor reactivity and temporary confusional state (p < 0.05). These data indicate that vasomotor reactivity, as measured by the Doppler‐carbon dioxide test, is a reliable tool to identify patients at risk for postoperative psychological disturbances.
The effect of the lateral decubitus position on vagal tone
Authors: Chen G.‐Y. , Kuo C.‐D.
Published: January 2004

The average person spends about one‐third of their time in a recumbent position. However, little is known about the effect of recumbent posture on autonomic nervous activity. Manoeuvres which can increase vagal tone have been sought both in the normal subject and in patients with heart disease. We have studied the autonomic effect of various recumbent positions, namely the supine, left lateral decubitus and right lateral decubitus positions, in healthy subjects by using spectral heart rate variability analysis. Both time‐ and frequency‐domain measures were calculated and compared between the three recumbent positions. The normalised high‐frequency power was used as the index of cardiac vagal activity, the normalised low‐frequency power as the index of cardiac sympathetic activity and the low‐frequency power/high‐frequency power ratio as the index of sympathovagal balance. The normalised high‐frequency power is highest in the right lateral decubitus position, followed in decreasing order by left lateral decubitus and supine positions. The low‐frequency power/high‐frequency power ratio has the reversed trend as compared with that of the normalised high‐frequency power. These results suggest that cardiac vagal activity is greatest when the right lateral decubitus position is adopted.
A survey of postoperative nausea and vomiting
Authors: Koivuranta M. , Läärä E. , Snåre L. , Alahuhta S.
Published: January 2004

A prospective interview‐based survey on the incidence of postoperative nausea and vomiting in 1107 in‐patients aged 4–86 years was conducted during a 3‐month period. Nausea, emetic episodes and the need for anti‐emetic medication were recorded for 24 h postoperatively. In the recovery room, the incidence of nausea and vomiting was 18% and 5%, respectively. Over the whole 24‐h period, these figures were 52% and 25%, respectively; severe nausea was experienced by 8%. The highest incidence of emetic sequelae was observed in gynaecological patients; 52% of the 822 patients who received general anaesthesia and 38% of the 285 patients who received regional anaesthesia reported nausea. The most important predictive factors associated with an increased risk for nausea and vomiting were female gender, a previous history of postoperative sickness, a longer duration of surgery, nonsmoking and a history of motion sickness. Based on these five items, a simple score predicting the risk of nausea and vomiting was constructed with a moderately good discriminating power.
A comparison of midazolam with trimeprazine as an oral premedicant for children
Authors: Mitchell V. , Grange C. , Black A. , Train J.
Published: January 2004

The effect of oral premedication was investigated in a double‐blind, randomised trial in 85 children undergoing tonsillectomy and/or adenoidectomy. Orally administered midazolam 0.5 mg.kg−1 given 30 min pre‐operatively was compared with trimeprazine 2 mg.kg−1 given 90 min pre‐operatively and a placebo preparation. Compliance, sedation and ease of induction were assessed as were the duration and quality of recovery. Following premedication with midazolam none of the patients was anxious, crying or distressed on leaving the ward, compared with 2/28 in the trimeprazine group and 5/28 in the placebo group (p =0.0007). More patients were calm and quiet on arrival in the anaesthetic room following midazolam than following trimeprazine, with both premedicant agents comparing favourably with placebo. There was no significant difference between the three groups in the time to recovery or the sedation score on discharge to the ward. Midazolam is a safe and effective oral premedicant for children.
Dose–response relationship and effective time to satisfactory intubation conditions after rocuronium in children
Authors: Hopkinson J. M. , Meakin G. , McCluskey A. , Baker R. D.
Published: January 2004

We assessed the neuromuscular blocking effects of, and intubation conditions following, rocuronium in 81 children aged 2–12 years. The study was conducted in three parts. Parts 1 and 2 were undertaken during anaesthesia with thiopentone, alfentanil and nitrous oxide. Neuromuscular blockade was evaluated by recording the force of contraction of the adductor pollicis in response to train‐of‐four stimulation at 2 Hz repeated every 10 s. In Part 1 the potency of rocuronium was determined in 15 children using a single dose–response technique; in Part 2 onset and recovery times were determined in six children following rocuronium 0.6 mg.kg−1. In Part 3 of the study, intubation conditions were assessed in five groups of 12 children whose tracheas were intubated 30, 40, 50, 60 and 70 s after rocuronium 0.6 mg.kg−1 during anaesthesia with thiopentone. The times to satisfactory intubation conditions in 50% and 90% of children were determined by probit analysis. The effective doses of rocuronium to produce 50% and 95% twitch depression were 151 μg.kg−1 (95% confidence intervals: 129–173 μg.kg−1) and 331 μg.kg−1 (95% confidence intervals: 249–543 μg.kg−1), respectively. The mean times (SD) to 90% and 100% depression of control twitch following rocuronium 0.6 mg.kg−1 were 42 (11.8) s and 60.3 (19.3) s, respectively. The times to 5%, 25%, 75% and 90% recovery were 20.5 (3.1) min, 26.1 (4.1) min, 35.1 (5.4) min, and 39.5 (6.4) min, respectively. Intubation conditions were satisfactory in 4/12 children at 30 s, 6/12 at 40 s, 8/12 at 50 s, 11/12 at 60 s and 12/12 at 70 s. The times to satisfactory intubation conditions in 50% and 90% of children after rocuronium 0.6 mg.kg−1 were 38 s (95% confidence intervals: 30–44 s) and 61 s (95% confidence intervals: 55–70 s), respectively.
Reshaping the Macintosh blade using biomechanical modelling#A prospective comparative study in patients
Authors: Bucx M. J. L. , Snijders C. J. , Van Der Vegt M. H. , Holstein J. D. , Stijnen T.
Published: January 2004

It has been demonstrated that during routine use of the Macintosh blade, great forces are exerted on the maxillary incisors. The aim of this study was, by using biomechanical modelling, to modify a standard Macintosh blade in order to reduce these forces. This resulted in a Macintosh blade with a reduced proximal flange. Five anaesthetists performed tracheal intubation in 46 patients using the modified (n =24) or the standard blade (n = 22). The mean (SD) maximal forces exerted on the maxillary incisors were 12.7 (8.8) N in patients in the modified Macintosh group compared to 25.5 (17.8) N in the standard Macintosh group (p =0.008). These results demonstrate that reducing the proximal step of the Macintosh laryngoscope results in a reduction of the forces exerted on the teeth and suggest that laryngoscope blades with a high proximal step might be more traumatic than blades in which the proximal step is reduced.
The loss of sevoflurane from a closed breathing system
Authors: Vagts D. A. , Lockwood G. G.
Published: January 2004

When volatile anaesthetics are used in a closed breathing system it is usually assumed that inflow of anaesthetic to the system matches uptake by the patient. Early laboratory reports on the interactions between sevoflurane and soda lime cast doubt on that assumption. We have measured the loss of sevoflurane, desflurane and isoflurane from a closed breathing system and found no differences of consequences.
The effect of single‐handed cricoid pressure on neck movement after applying manual in‐line stabilisation
Authors: Gabbott D. A.
Published: January 2004

In 30 ASA 1 and 2 patients undergoing general anaesthesia and neuromuscular paralysis, manual in‐line stabilisation of the neck in a neutral position was performed and single‐handed cricoid pressure was applied. Vertical displacement was measured from the midpoint of the neck (directly below the cricoid cartilage). Measurements were also made at the tragus of the ear and the shoulder, both of which acted as fixed reference points. Mean neck displacement was 4.6 mm with a range of 0–8 mm. Mean tragus and shoulder displacements were 0.5 mm and 0.9 mm, respectively, with a range of 0–2 mm at each point. Vertical displacement was also measured in 10 patients from a stylet fixed to the posterior aspect of the neck. Mean displacement measured at this point was 5.0 mm with a range of 2–9 mm. Single‐handed cricoid pressure caused vertical displacement of the neck of between 4.6 and 5 mm with a range of 0–9 mm. Only some of this movement, i.e. 0.5–0.9 mm (range 0–2 mm) can be accounted for by displacement of the whole patient as determined from measurements at the two fixed reference points. These findings have implications for emergency management of the airway in trauma patients.
Pain relief with oral cannabinoids in familial Mediterranean fever
Authors: Holdcroft A. , Smith M. , Jacklin A. , Hodgson H. , Smith B. , Newton M. , Evans F.
Published: January 2004

Cannabinoids have analgesic and, possibly, anti‐inflammatory properties but their clinical use has been restricted by legislation. This is the first United Kingdom report of the controlled use of a standardised pharmaceutical preparation of cannabinoids in capsular form. The therapy was assessed in a patient with familial Mediterranean fever, who presented with chronic relapsing pain and inflammation of gastrointestinal origin. After determining a suitable analgesic dosage, a double‐blind placebo‐controlled cross‐over trial was conducted using 50 mg tetrahydrocannabinol daily in five doses in the active weeks and measuring effects on parameters of inflammation and pain. Although no anti‐inflammatory effects of tetrahydrocannabinol were detected during the trial, a highly significant reduction (p < 0.001) in additional analgesic requirements was achieved. Future study designs can now incorporate prescribable forms of cannabinoids but the choice of previous cannabis users only as patients has clinical limitations. Cannabis naive patients would tolerate controlled investigations but may generate medicolegal problems.
End‐tidal oxygraphy and safe duration of apnoea in young adults and elderly patients
Authors: Bhatia P. K. , Bhandari S. C. , Tulsiani K. L. , Kumar Y.
Published: January 2004

Using an end‐tidal fractional oxygen concentration of 0.9 as an end point for pre‐oxygenation, we have compared the time taken to achieve this end point and the safe duration of apnoea after induction of anaesthesia following pre‐oxygenation in elderly patients and young adults. The times taken to reach the end point of pre‐oxygenation and for the oxygen saturation to decrease to 92% during a period of apnoea were found not to be significantly different between the two age groups. It is concluded that in spite of the physiological changes that occur with age, end‐tidal oxygen concentration monitoring is as useful in the elderly population as in young adults as an end point for pre‐oxygenation.
Acupuncture in the prevention of postoperative nausea and vomiting
Authors: Al‐Sadi M. , Newman B. , Julious S. A.
Published: January 2004

The efficacy of intra‐operative acupuncture at the PC6 point in the prevention of postoperative nausea or vomiting was studied. A double‐blind randomised controlled study of acupuncture versus placebo was performed in 81 patients scheduled for day case gynaecological laparoscopic surgery. Failure of treatment was defined as the occurrence of nausea or vomiting prior to or within 24 h of discharge. The use of acupuncture reduced the incidence of postoperative nausea or vomiting in hospital from 65% to 35% compared with placebo and after discharge from 69% to 31% compared with placebo.
End‐tidal carbon dioxide measurement and breathing system filters
Authors: Hardman J. G. , Curran J. , Mahajan R. P.
Published: January 2004

Breathing system filters are recommended for use during general anaesthesia. Manufacturers of gas sampling equipment recommend that gas is sampled from the ‘machine side’ of these filters, thereby avoiding contamination of the sampling line and waterlogging in the case of heat and moisture exchangers. The aim of this study was to investigate differences between the measured end‐tidal carbon dioxide values at either side of the filter. Fifteen adults were studied during mechanical ventilation and 15 during spontaneous ventilation under general anaesthesia. End‐tidal carbon dioxide values were significantly lower at the machine side of the filter in both groups (p = 0.00001). The measurement error induced by the inclusion of the breathing system filter was significantly greater in the spontaneously breathing group (p = 0.0004).
The peri‐operative use of the oesophageal Doppler monitor in patients undergoing coronary artery revascularisation#A comparison with the continuous cardiac output monitor
Authors: Krishnamurthy B. , McMurray T. J. , McClean E.
Published: January 2004

This study was carried out to evaluate the ease of use and reliability of cardiac output estimations performed by an oesophageal Doppler monitor and to compare its use with that of a continuous cardiac output pulmonary flotation catheter. Measurements were made during and after surgery in 16 patients scheduled to undergo coronary revascularisation. Both devices suffered significant intra‐operative problems which led us to question their suitability as operating theatre monitors. After surgery the continuous cardiac output monitor provided stable results while the oesophageal Doppler monitor required the continuous presence of an experienced anaesthetist to ensure comparable cardiac output estimations.
Leakage of fluid around low‐pressure tracheal tube cuffs
Authors: Oikkonen M. , Aromaa U.
Published: January 2004

The aim of the study was to evaluate leakage of liquid past the low‐pressure cuffs of tracheal tubes. Ten samples of each of nine different types of tubes were tested in a PVC mock trachea, using intracuff pressures of 20, 30, 40 and 50 cmH2O. In five types of tubes, 6–10 cuffs allowed profuse leakage (> 20 ml water in 5 min) even at the highest intracuff pressure, i.e. 50 cmH2O. In the most efficient tube, all the cuffs were leak‐proof (leakage < 5 ml in 5 min) at 40 cmH2O and in the second best type the cuffs were leak‐proof at 50 cmH2O. The leakage of fluid past the tracheal tube remains an unresolved problem with low‐pressure cuffs.
Neonatal welfare and placental transfer of fentanyl and bupivacaine during ambulatory combined spinal epidural analgesia for labour
Authors: Fernando R. , Bonello E. , Gill P. , Urquhart J. , Reynolds F. , Morgan B.
Published: January 2004

To investigate current concerns that potent opioid drugs, such as fentanyl, used for labour regional analgesia may affect neonatal status, maternal and umbilical plasma concentrations of fentanyl and bupivacaine at delivery were measured in 40 nulliparous patients receiving low‐dose combined spinal epidural analgesia. Neonatal assessments included Apgar scores, umbilical blood gases and neurobehavioural tests. All maternal and umbilical venous plasma concentrations were low. Maternal and umbilical vein total fentanyl concentrations increased with increasing doses of epidural fentanyl (r = 0.46 and 0.30, respectively, p < 0.01). There were no significant differences between maternal and umbilical venous plasma total or free concentrations of fentanyl. Mean umbilical vein/maternal fentanyl ratios were 1.12 for total drug and 1.20 for free drug and values were unrelated to the last epidural bolus to delivery interval (r = 0.12, p = 0.49). There were no correlations between Apgar scores, umbilical blood gases or neurobehavioural scores and umbilical venous concentrations of either fentanyl or bupivacaine. The dose of fentanyl used for ambulatory combined spinal epidural analgesia would appear to have a negligible effect on neonatal condition.
Isoflurane for removal of chest drains after cardiac surgery
Authors: Bryden F. M. M. , McFarlane H. , Tunstall M. E. , Ross J. A. S.
Published: January 2004

Thirty‐five patients who had undergone uncomplicated cardiac surgery were randomly allocated to receive either Entonox or isoflurane 0.25% in Entonox as inhalational analgesia for the removal of their two chest drains. The gases were presented premixed in high‐pressure cylinders and were self‐administered by means of a demand valve. The removal of the second drain was more painful than the first but that pain was better controlled by isoflurane 0.25% in Entonox than by Entonox alone.
Dreams, images and emotions associated with propofol anaesthesia
Authors: Brandner B. , Blagrove M. , McCallum G. , Bromley L. M.
Published: January 2004

One hundred and twelve patients scheduled for day case varicose vein surgery were randomly allocated to one of three groups: total intravenous anaesthesia with propofol, propofol induction followed by inhalational anaesthesia with nitrous oxide and isoflurane or thiopentone induction followed by inhalational anaesthesia with nitrous oxide and isoflurane. Assessments were made in the recovery room of the incidence of dreaming, the content of the dreams and the emotional status of the patients. The groups differed significantly in reporting that they had been dreaming: patients who underwent total intravenous anaesthesia reported the most dreaming and patients who received thiopentone the least. However, despite the large number of case reports of sexual imagery following propofol anaesthesia and despite the two groups who had received propofol experiencing significantly greater happiness upon recovery than the thiopentone group, there were no appreciable differences in the sexual content of the dreams. Each group had only a small number of dreams even remotely related to sex.
Selective serotonin reuptake inhibitorsPharmacology and clinical implications in anaesthesia and critical care medicine
Authors: Kam P. C. A. , Chang G. W. M.
Published: January 2004

The newer, selective serotonin reuptake inhibitors are increasingly used in psychiatry in both children and adults. Although they have fewer side‐effects, they can cause significant physiological changes and drug interactions which have implications for the anaesthetist and the critical care physician, especially the potential to induce the serotonin syndrome.
Detection of accidental oesophageal intubation Role of the anaesthetic assistant
Authors: Cameron A. E. , Hyde R. A. , Sivalingam P. , Asbury A. J.
Published: January 2004

Three situations in which an anaesthetic assistant might be able to detect accidental oesophageal intubation during or immediately after intubation were assessed. These were: firstly, whilst applying cricoid pressure, secondly, whilst applying gentle palpation over the trachea just above the suprasternal notch and, thirdly, after intubation by means of a ‘roll test’. During cricoid pressure, tracheal intubation was correctly diagnosed in all of 10 cases. However, deliberate oesophageal intubation was only detected in six out of 10 cases. During suprasternal palpation, three cases out of 10 oesophageal and three cases out of 10 tracheal intubation were misdiagnosed. In the ‘roll test’, two out of 10 tracheal and five out of 10 oesophageal intubations were misdiagnosed. In conclusion, no method could be relied on entirely and may indeed give false reassurance. Nonetheless, any doubt expressed about the tracheal tube position by the assistant should be taken seriously and a careful check made.
A cuff inflator for tracheal tubes
Authors: Abdelatti M. O. , Kamath B. S. K.
Published: January 2004

A simple automatic device* to inflate the tracheal tube cuff during emergency tracheal intubation is described. It was tested in 60 patients undergoing elective surgery and found to be a useful and efficient adjunct.
The effect of a heat and moisture exchanger on humidity in a low‐flow anaesthesia system
Authors: Henriksson B.‐Å. , Sundling J. , Hellman A.
Published: January 2004

The heat and humidity in a low‐flow breathing system was measured in order to study the inherent humidifying properties of the system at low fresh gas flows (< 1 and 2 l.min−1) and whether a heat and moisture exchanger could compensate for the loss of heat and humidification occurring at higher fresh gas flows (5 l.min−1) in these systems. Sixty patients were randomly divided into three groups (< 1, 2 and 5 l.min−1 fresh gas flows) with a heat and moisture exchanger and three groups without a heat and moisture exchanger in the breathing system. Thirty minutes after the start of anaesthesia a control measurement was performed, after which a heat and moisture exchanger was inserted into the breathing system of the three groups randomly allocated to have one. Three more measurements were performed at 10, 30 and 60 min after control. At low fresh gas flows the humidifying properties of the low‐flow breathing system are adequate (i.e. provide an absolute humidity > 20 mg.l−1) but at a fresh gas flow of 5 l.min−1 there is a need for a heat and moisture exchanger for adequate humidification of the inspired gas.
A comparison of the nasal mask and the nasopharygeal airway in paediatric chair dental anaesthesia
Authors: Bagshaw O. N. T. , Southee R. , Ruiz K.
Published: January 2004

This study compared the quality of anaesthesia and surgical access afforded by two techniques for the administration of anaesthesia during paediatric chair dental procedures. A total of 50 ASA 1 paediatric day case patients were randomly assigned to receive anaesthesia through either the traditional Goldman nasal mask or through a nasopharyngeal airway. Patients in the nasal mask group were judged to have significantly worse airway patency (p = 0.0001) and significantly more episodes of airway obstruction (14 vs. 4; p = 0.0032) than those in the nasopharygeal airway group. Anaesthetic, surgical and oxygen saturation data did not differ significantly between the two groups. Operating conditions were universally graded as excellent in the nasopharyngeal airway group, while those in the nasal mask group were graded as excellent/good in only 79% of cases (p < 0.0001). These results suggest that better quality anaesthesia and operating conditions can be achieved by using a nasopharyngeal airway rather than the traditional nasal mask for the administration of anaesthesia to paediatric chair dental patients.