bluuebunny/crossref_metadata_2025 huggingface dataset:
An evaluation of the factors influencing selection of the optimal size of laryngeal mask airway in normal adults
Authors: Berry A. M. , Brimacombe J. R. , McManus K. F. , Goldblatt M.
Published: March 2003

The purpose of this randomised single blinded study was to determine the optimal size of laryngeal mask airway in the normal adult population, to test the validity of the current selection criteria and to determine if any externally measured anatomical variable correlated with optimal size. In each of 30 apnoeic anaesthetised adults weighing less than 100 kg, size 3, 4 and 5 laryngeal mask airways were inserted in random order by a skilled user and the cuff inflated to a standard pressure (60 cmH2O). Optimal size was based on four criteria in order of priority: number of attempts at placement, oropharyngeal leak pressure, fibreoptic score and percentage of vocal cords seen. The size 5 laryngeal mask airway was optimal in 19/30 and the size 4 in 11/30. In no patient was the size 3 the optimal fit. Oropharyngeal leak pressure was significantly higher for each progressively larger size and the fibreoptic view was significantly better for the size 4 and size 5. There was no significant predictive value in any externally measured anatomical variable, but height was the most useful. The best current selection strategy was to choose a size 5 for males and size 4 for females. Potentially useful new strategies may be to use the size 5 in all adults, or a size 5 ≥ 165 cm in height and size 4 for < 165 cm. We conclude that predicting the optimal size of laryngeal mask airway for individual adult patients is complex. The best size selection strategies involve use of the size 4 and 5 laryngeal mask airways in adults.
The uptake of sevoflurane during anaesthesia
Authors: Vagts D. A. , Lockwood G. G.
Published: March 2003

The rate of uptake of sevoflurane during clinical anaesthesia (1.3 MAC) was measured by computer‐controlled injection of liquid anaesthetic into a closed breathing system. The cumulative uptake of sevoflurane was 4.8 ml, 7.4 ml. 9.5 ml and 11.5 ml at 30, 60, 90 and 120 min, respectively. The ratio of inspired to end‐expired sevoflurane was greater than similar measurements we have made for desflurane in the past, but the absolute rate of sevoflurane uptake was less than the rate of uptake of desflurane in these cases. The rate of uptake was equivalent to 0.59e−0.32t + 0.039e−0.036t + 0.105e−0.0034t mlmin−1 liquid sevoflurane. Plasma urea and creatinine measured on the first postoperative day were not significantly different from pre‐operative values.
Lung aeration and pulmonary gas exchange during lumbar epidural anaesthesia and in the lithotomy position in elderly patients
Authors: Reber A. , Bein T. , Högman M. , Khan Z. P. , Nilsson S. , Hedenstierna G.
Published: March 2003

We investigated a total of 36 subjects with a mean (SD) age of 65 (13) years, during baseline conditions (supine, before any anaesthesia), and then during one of the following protocols: (1) lithotomy positioning (n = 12), (2) epidural anaesthesia (n = 12), (3) general anaesthesia in the supine position (n = 12). Lung aeration, ventilation/perfusion matching, gas exchange and functional residual capacity were measured. Lung aeration was normal during baseline assessment with almost no regions with poor aeration and no substantial dependent densities. Shunt and perfusion of poorly ventilated regions were minor. Lithotomy positioning did not reduce functional residual capacity and did not affect aeration of the lung or ventilation/perfusion matching. Epidural anaesthesia, in general, had no effect on aeration, ventilation/perfusion matching or gas exchange, regardless of whether the patient was in the supine or lithotomy position. General anaesthesia, however, caused significant increases in poorly aerated lung regions and in dependent densities (interpreted as atelectasis). In conclusion, no or little impairment of lung aeration and ventilation/perfusion matching was caused by the lithotomy position and/or epidural anaesthesia, contrary to the effects seen during general anaesthesia. However, our findings also suggest that being overweight is a factor that may cause impairment of lung aeration.
A survey of the practice of thoracic epidural analgesia in the United Kingdom
Authors: Romer H. C. , Russell G. N.
Published: March 2003

A postal survey of the practice of thoracic epidural analgesia was sent to 275 hospitals in the United Kingdom. Responses were received from 70% of hospitals. Informed consent is rarely adequately obtained, with only 28% of respondents mentioning even the most common complications. Epidural cannulation is most often (60%) performed following induction of general anaesthesia, rather than in the awake patient. A test dose of local anaesthetic without adrenaline is usual. Neither aspirin nor low‐dose heparin are considered a contraindication. The majority of respondents used a combination of bupivacaine with fentanyl (51%) or diamorphine (40%), usually administered by continuous infusion. Drugs were frequently prepared and adjusted by anaesthetic staff. The majority of epidurals (63%) are nursed in intensive care units postoperatively. Properly funded pain management teams, at present unusual, would facilitate ward‐based epidural management and release intensive care resource. A central register of epidural complications is required to provide valuable evidence for the optimum practice of thoracic epidural analgesia.
Evaluation of remifentanil for control of haemodynamic response to tracheal intubation
Authors: McAtamney D. , O'Hare R. , Hughes D. , Carabine U. , Mirakhur R.
Published: March 2003

We have studied the effect of three bolus doses of remifentanil on the haemodynamic response to laryngoscopy and tracheal intubation. Using a double‐blind design, 80 ASA 1 or 2 patients presenting for elective surgery received saline placebo or remifentanil 0.25, 0.5 or 1.0 μg.kg−1 by random allocation. Anaesthesia was induced with thiopentone 5–7 mg.kg−1 and followed immediately by the study medication given as a bolus over 30 s. Muscle relaxation was provided with rocuronium 0.75 mg.kg−1. The patients' tracheas were intubated under direct laryngoscopy 1 min later. Noninvasive arterial blood pressure and heart rate were recorded immediately before induction of anaesthesia and then at intervals until 5 min after tracheal intubation. There was a significant increase in heart rate (p < 0.01) and systolic arterial pressure (p < 0.01) in all groups after tracheal intubation. However, this was short‐lived and of a smaller magnitude in the remifentanil 1 μg.kg−1 group in which the increase was significantly lower than in the control group (p < 0.01).
The relevance of clinical and radiological measurements in predicting difficulties in fibreoptic orotracheal intubation in adults
Authors: Randell T. , Hakala P. , Kyttä J. , Kinnunen J.
Published: March 2003

Resistance to the passage of the tracheal tube has been reported to occur in up to 36% of patients subjected to orotracheal fibreoptic intubation. In this prospective study we assessed five radiological measurements of the upper airway in an attempt to find anatomical causes of obstruction to passage of the tube. Forty‐nine patients undergoing fibreoptic orotracheal intubation under general anaesthesia were studied. Pre‐operatively, the Mallampati grade and the thyromental distance were assessed. The plain films, CT scans or MR images of the cervical spine were used for measurement of the position of the vocal cords, the length of the epiglottis and the size of the tongue. The resistance to the passage of the tube was graded as none, mild, moderate or severe. The length of the epiglottis and the size of the tongue, but not the position of the vocal cords, had positive correlations with the severity of impingement. The pre‐operative bedside tests did not correlate with difficulties in fibreoptic intubation.
Side‐effects of epidural infusions of opioid bupivacaine mixtures
Authors: Gedney J. A. , Liu E. H. C.
Published: March 2003

The incidence of side‐effects occurring with epidural diamorphine (0.05 mg.ml−1), fentanyl (2.0 μg.ml−1), methadone (0.1 mg.ml−1), morphine (0.05 mg.ml−1) and pethidine (1.0 mg.ml−1) used by infusion in combination with bupivacaine has been compared. One hundred and sixty patients were studied, 32 receiving each opioid. The incidence of nausea and vomiting was significantly greater with morphine than fentanyl (p = 0.0097) and pethidine (p = 0.0021). The incidence of pruritis was significantly greater with morphine and diamorphine than with methadone (p = 0.012) and pethidine (p = 0.027). Morphine was also associated with a significantly greater incidence of urinary retention than pethidine (p = 0.012) and methadone (p = 0.025).
A comparison of two airway aids for emergency use by unskilled personnelThe Combitube and laryngeal mask
Authors: Yardy N. , Hancox D. , Strang T.
Published: March 2003

Many non‐anaesthetists find airway control and intubation difficult. The laryngeal mask has been advocated for use by non‐anaesthetists at cardiorespiratory arrests, whilst the Combitube is said to provide protection from aspiration. We wished to determine which device was easiest for unskilled staff to use. Staff not previously trained in airway support were briefly taught insertion of each device. Twenty‐six ASA 1 or 2 adults, requiring muscle relaxation and tracheal intubation for surgery, were recruited to this randomised crossover study. Both devices were inserted in random order and the time to successful ventilation of the lungs recorded. Both devices were successfully placed in 24/26 patients. The median times to insertion were 40 s and 45 s for the laryngeal mask and Combitube, respectively, with two failures, both with the Combitube (p > 0.05); these were due to faulty operator technique. The Combitube may be a suitable alternative to the laryngeal mask for use in resuscitation by unskilled staff.
Continuous pulse oximetry in the general surgical ward: Nellcor N‐200 versus Nellcor N‐3000
Authors: Christensen M. , Lie C. , Rosenberg J.
Published: March 2003

New measurement principles in pulse oximetry have been introduced to decrease the incidence of false movement alarms. Experimental studies have shown that the new Nellcor Symphony N‐3000 may reduce the incidence of false alarms when monitoring during different activities. We compared the Nellcor Symphony N‐3000 with the Nellcor N‐200 pulse oximeter, when monitoring patients in the general surgical ward. Twenty‐two patients were monitored during unrestricted ward activities for a total of 275 h with a N‐3000 and a N‐200 pulse oximeter simultaneously. Data were analysed for lack of concordance between the two pulse oximeters with respect to frequency of registered hypoxaemic episodes and thus the amount of time spent in the alarm state. The median number of desaturation episodes with the N‐200 was 18 (range 0–511) compared with four (range 0–476) with the N‐3000 (p < 0.0001). The median number of drop‐outs (loss of signal) was 13 (range 1–46) with the N‐200 compared with nine (2–41) with the N‐3000 (p = 0.06). The N‐200 registered saturation values of 85% or below for 23% of the observation time compared with 6% of the observation time with the N‐3000 pulse oximeter (p < 0.0001). The different working principles of the two generations of oximeters were reflected in the present results derived from a clinical setting. The Nellcor Symphony N‐3000 may offer an advantage compared with the Nellcor N‐200, because of the reduced frequency of alarms and total time in alarm when monitoring patients in the general surgical ward.
Ventilatory pattern and associated episodic hypoxaemia in the late postoperative period in the general surgical ward
Authors: Rosenberg J. , Rasmussen G. I. , Wøjdemann K. Reinhold , Kirkeby L. Tschemerinsky , Jørgensen L. Nannestad , Kehlet H.
Published: March 2003

Episodic oxygen desaturation is frequent in the late postoperative period and seems most pronounced on the second and third postoperative nights. However, the ventilatory pattern has not been described systematically during this period. We studied the ventilatory pattern and associated arterial oxygenation using the Edentrace II equipment (impedance pneumography and pulse oximetry) on the second and third postoperative nights in 28 patients undergoing major abdominal surgery. Ventilatory disturbances were common and included periods of hypopnoea, and obstructive, central and mixed apnoeas. Overall, the median (range) respiratory disturbance index (apnoeas + hypopnoeas per h) was 12 (0–121), with the patients spending 6% (0–65%) of the night in some kind of ventilatory disturbance. It was not possible from pre‐operative snoring habits to predict patients who developed postoperative ventilatory disturbances. Overall, 23% (0–100) of the hypopnoeas and 7% (0–100) of the apnoeas were associated with episodic hypoxaemia. In conclusion, ventilatory disturbances were common in the late postoperative period in the general surgical ward and often associated with episodes of oxygen desaturation.
Development and evaluation of combined rectus sheath and ilioinguinal blocks for abdominal gynaecological surgery
Authors: Yentis S. M. , Hills‐Wright P. , Potparic O.
Published: March 2003

We describe the development of a technique of combined rectus sheath and ilioinguinal blocks for patients undergoing abdominal gynaecological surgery, and its use in a series of 37 patients (21 midline and 16 transverse incisions). Up to 60 ml of bupivacaine 0.25% with adrenaline 1:400 000 was used, depending on the patient's weight. Median (interquartile range) total morphine requirement (including 0.15 mg.kg−1 given intra‐operatively) up to 48 h after surgery was 0.34 (0.2–0.38) mg.kg−1 for midline incisions and 0.47 (0.35–0.64) mg.kg−1 for transverse incisions; no other systemic opioids were given. Six‐hourly pain scores within the first 48 h after surgery were ≤1 (mild pain) in 11 out of 21 (52%) and ≤2 (moderate pain) in 18 out of 21 (86%) patients with midline incisions and in 5 out of 16 (31%) and 13 out of 16 (81%) patients with transverse incisions, respectively. No patient had emetic symptoms worse than mild nausea during the 48‐h postoperative study period.
Portable ultrasonic scanning of the anterior neck before percutaneous dilatational tracheostomy
Authors: Hatfield A. , Bodenham A.
Published: March 2003

We used portable ultrasound scans to identify relevant anatomical structures in the necks of 30 patients before percutaneous tracheostomy. We identified the tracheal midline, thyroid isthmus and blood vessels and located a safe level for needle insertion. Anterior jugular veins were seen in 15 patients; eight were near the midline and were considered vulnerable. Three veins were more than 4 mm in diameter and these larger vessels were electively ligated. Four patients had arteries which were considered vulnerable to damage. All patients underwent successful percutaneous tracheostomy. Portable ultrasound provides a simple method of screening for vulnerable blood vessels in the neck and for locating the midline before percutaneous tracheostomy. This method is particularly suitable for patients with landmarks that are difficult to visualise or palpate. Based on the ultrasonic findings we can make an informed decision about referral for surgical tracheostomy.
Comparison of remifentanil with alfentanil or suxamethonium following propofol anaesthesia for tracheal intubation
Authors: Alexander R. , Booth J. , Olufolabi A. J. , El‐Moalem H. E. , Glass P. S.
Published: March 2003

Sixty ASA physical status I and II, premedicated patients were administered propofol 2 mg.kg−1 and remifentanil 2 μg.kg−1 (group R), alfentanil 50 μg.kg−1 (group A) or suxamethonium 1 mg.kg−1 (group S) as a rapid bolus. One minute after study drug administration, tracheal intubation was performed. Intubation conditions were then scored. Excellent or good conditions were observed in only 35% in group R compared with groups S and A (100% and 85%, respectively; p < 0.001). The haemodynamic response to tracheal intubation was blunted in groups R and A compared with group S (p < 0.001). The mean heart rate in groups R and A was significantly lower than group S (p < 0.001). We conclude that remifentanil 2 μg.kg−1 given as a rapid bolus will not produce intubating conditions as good as those obtained with alfentanil 50 μg.kg−1 or suxamethonium 1 mg.kg−1 if administered after propofol 2 mg.kg−1.
Double‐blind comparative study of droperidol, granisetron and granisetron plus dexamethasone as prophylactic anti‐emetic therapy in patients undergoing abdominal, gynaecological, breast or otolaryngological surgery
Authors: Janknegt R. , Pinckaers J. W. M. , Rohof M. H. C. , Ausems M. E. M. , Arbouw M. E. L. , Van Der Velden R. W. , Brouwers J. R. B. J.
Published: March 2003

In this double‐blind study the clinical efficacy of a single pre‐operative intravenous dose of droperidol 1.25 mg (137 patients), granisetron 1 mg (130 patients) and granisetron 1 mg plus dexamethasone 5 mg (130 patients) was investigated for the prevention of postoperative nausea and vomiting after gynaecological surgery, breast surgery, abdominal surgery and ear, nose and throat surgery. The incidence of nausea in the first 24 h postoperatively was 52% in the droperidol group, 48% in the granisetron group and 34% with the combination, respectively. Both granisetron and granisetron/dexamethasone performed better than droperidol in their effects on vomiting or combined nausea and vomiting (incidence in the first 24 h 22%, 18% and 42%, respectively). The number of emetic episodes during the 5‐day study period was significantly higher in the droperidol group (198) than in the granisetron (73) or combination group (78).
Extending low‐dose epidural analgesia for emergency Caesarean sectionA comparison of three solutions
Authors: Lucas D. N. , Ciccone G. K. , Yentis S. M.
Published: March 2003

We conducted a prospective double‐blind randomised trial to compare bupivacaine 0.5%; a 50 : 50 mixture of bupivacaine 0.5%/lignocaine 2% with 1 : 200 000 adrenaline (final concentration); and lignocaine 2% with 1 : 200 000 adrenaline for converting a low‐dose labour epidural into a block adequate for emergency Caesarean section. Ninety patients were studied, 30 in each group. There was no difference between the groups in the time taken for bilateral loss of cold sensation to reach T4. Onset time was unaffected by the existing sensory level pre‐Caesarean section top‐up; the number of low‐dose top‐ups in labour; the total dose of bupivacaine in labour; or maternal weight or height. Three patients in the lignocaine with adrenaline group had blocks that reached the cervical dermatomes and three in the same group required general anaesthesia for inadequate anaesthesia, compared with none in the other groups (both p = 0.04).
Preliminary UK experience of dexmedetomidine, a novel agent for postoperative sedation in the intensive care unit
Authors: Venn R. M. , Bradshaw C. J. , Spencer R. , Brealey D. , Caudwell E. , Naughton C. , Vedio A. , Singer M. , Feneck R. , Treacher D. , Willatts S. M. , Grounds R. M.
Published: March 2003

Dexmedetomidine, a highly selective and potent α2‐adrenergic agonist, has a potentially useful role as a sedative agent in patients requiring intensive care. As part of a larger European multicentre trial, a total of 119 postoperative cardiac and general surgical patients requiring ventilation and sedation in an intensive care unit were enrolled in four centres in the United Kingdom. One hundred and five patients were randomly allocated to receive either dexmedetomidine or placebo with rescue sedation and analgesia provided by midazolam and morphine, respectively. Compared with the control group, intubated patients receiving dexmedetomidine required 80% less midazolam [mean 4.9 (5.8) μg.kg−1.h−1 vs. 23.7 (27.5) μg.kg−1.h−1, p < 0.0001], and 50% less morphine [11.2 (13.4) μg.kg−1.h−1 vs. 21.5 (19.4) μg.kg−1.h−1,p = 0.0006]. Cardiovascular effects and adverse events could be predicted from the known properties of alpha‐2 agonists. In conclusion, dexmedetomidine is a useful agent for the provision of postoperative analgesia and sedation.
Pretreatment with ketorolac and venous occlusion to reduce pain on injection of propofol
Authors: Yull D. N. , Barkshire K. F. , Dexter T.
Published: March 2003

We performed a randomised, double‐blind, prospective trial to discover whether intravenous ketorolac 10 mg made up to 2 ml with saline, with or without venous occlusion for 2 min, reduces the pain on injection of propofol. In 90 patients, pain scores were obtained during injection of propofol following pretreatment of the vein with saline, ketorolac or ketorolac with venous occlusion. Pain on injection of ketorolac was more common than with saline (p = 0.02). The incidence of severe pain following propofol was reduced by ketorolac with venous occlusion (p = 0.019) compared with saline or ketorolac without venous occlusion. There was no difference in venous sequelae at 7 days postoperatively between the groups. Our results suggest that pain on injection of propofol may be related to release of local kininogens and that nonsteroidal anti‐inflammatory drugs may have a role in reducing that pain.
Patient‐controlled intranasal diamorphine for postoperative pain:
Authors: Hallett A. , O’Higgins F. , Francis V. , Cook T. M.
Published: March 2003

A patient acceptability study was conducted using patient‐controlled intranasal diamorphine. Patients undergoing nonemergency orthopaedic or gynaecological surgery self‐administered intranasal diamorphine for 24 h postoperatively. Pain, pain relief, sedation, respiratory rate, nausea and vomiting were assessed regularly. After 24 h, patients and their attending nurses completed a questionnaire assessing satisfaction and practical aspects of the technique. Satisfaction was reported as good or complete by 69% of patients and 69% of nurses. Pain relief was assessed as better than expected by 45% of patients and better than normal by 50% of nurses. Seventy‐nine per cent of patients would be pleased to use patient‐controlled intranasal diamorphine again and 89% of nurses would be happy for their patients to use it again. Sedation was uncommon and mild and there were no episodes of significant respiratory depression. Fifty‐three per cent of patients reported no nausea and 74% did not vomit at any stage. There were seven withdrawals, four due to problems with the device and three due to therapeutic problems. The nasal spray may need modification to improve reliability. However, we found patient‐controlled intranasal analgesia an effective technique, which was well tolerated by patients and nurses and was without unpleasant side‐effects. Further work to determine how it performs compared with intramuscular or intravenous analgesia is now needed.
Succinylcholine‐associated postoperative myalgia
Authors: Wong S. F. , Chung F.
Published: March 2003

The subject of postoperative myalgia associated with the use of succinylcholine is reviewed. We discuss the mechanisms of succinylcholine‐induced myalgia and the techniques available to prevent and treat the myalgia. In situations where patients are at risk of developing myalgia and succinylcholine is the neuromuscular blocker of choice, the use of a combination of techniques may prove to be a useful strategy.
Sevoflurane – nitrous oxide anaesthesia supplemented with remifentanil: effect on recovery and cognitive function
Authors: Breslin D. S. , Reid J. E. , Mirakhur R. K. , Hayes A. H. , McBrien M. E.
Published: March 2003

The aim of this study was to compare recovery and psychomotor performance after maintenance of anaesthesia with sevoflurane or sevoflurane supplemented with remifentanil. Sixty‐six per cent nitrous oxide was used in all patients. Twenty patients each were randomly allocated to maintenance of anaesthesia with sevoflurane only in concentrations necessary to maintain adequate anaesthesia or with 1.5, 1.0 or 0.5 MAC (end‐tidal) of sevoflurane supplemented with remifentanil. The median dosage of remifentanil required in the last three groups was 0.21, 0.25 and 0.34 µg.kg−1.min−1, respectively (p < 0.05). The median times to eye opening were 10.3, 12.7, 11.0 and 6.5 min in the four groups (p < 0.05 between the 0.5 MAC and the other groups) and for orientation 12.1, 14.9, 12.3 and 8.3 min, respectively (p < 0.05 between 0.5 and 1.5 MAC groups). There was no significant difference in the mini‐mental state assessment scores or the actual discharge times from the recovery ward among the groups. Significantly greater numbers of patients could perform the critical flicker fusion test at 15 min in the group receiving the lowest concentration of sevoflurane and the highest dosage of remifentanil (p < 0.05). Patients in this group also showed the highest incidence of chest wall rigidity (p < 0.003). We conclude that, while the use of remifentanil with lower concentrations of sevoflurane facilitates early recovery, it does not influence discharge time from recovery ward and may be associated with side‐effects such as chest wall rigidity.
Facilitation of laryngeal mask airway insertion Effects of remifentanil administered before induction with target‐controlled propofol infusion
Authors: Grewal K. , Samsoon G.
Published: March 2003

Eighty‐six adult day‐case patients were recruited into a prospective, randomised study and allocated to one of two groups. Patients received either intravenous remifentanil 0.3 µg.kg−1 or an equivalent volume of sodium chloride 0.9% followed by induction of anaesthesia with propofol target‐controlled infusion until the effect (brain) site calculated concentration was 2 µg.ml−1. Jaw opening and ease of laryngeal mask insertion were assessed immediately after mask insertion. A higher incidence of failure of induction of anaesthesia was observed in the control group compared with the remifentanil group [15 (35%) vs. 3 (7%); p < 0.01] and addition of remifentanil significantly increased the ease and success of laryngeal mask insertion, with grade 1 (no coughing/gagging) conditions observed in 29 (68%) of the remifentanil group and 21 (49%) of the control group (p < 0.01).The doses of remifentanil and propofol used were not associated with any significant cardiorespiratory instability. In conclusion, when combined with propofol target‐controlled infusion, remifentanil 0.3 µg.kg−1 facilitates laryngeal mask insertion with minimal adverse haemodynamic changes.
Supplementary oxygen administration for elective Caesarean section under spinal anaesthesia
Authors: Cogliano M. S. , Graham A. C. , Clark V. A.
Published: March 2003

We investigated the necessity for administration of supplementary oxygen to mothers undergoing elective Caesarean section under spinal anaesthesia. Sixty‐nine women undergoing elective Caesarean section were randomly allocated to one of three groups to be given either oxygen (40%) by facemask, air by facemask or oxygen at 2 l.min−1 by nasal cannulae. Umbilical arterial and venous blood samples were taken and analysed immediately after delivery. The results showed that there were no significant differences in the umbilical arterial or venous pH, partial pressure of oxygen and partial pressure of carbon dioxide between any of the three groups. We also assessed the patient acceptability of oxygen administered by facemask vs. nasal cannulae should the need for supplementary oxygen arise. It was found that use of the facemask impeded communication.
Supervision of trainee anaesthetists: a survey of opinions and practices
Authors: Kerr J. , Skinner A.
Published: March 2003

This questionnaire survey investigated the different degrees of supervision of trainee anaesthetic senior house officers (SHOs) in hospitals across the United Kingdom, and compared it with past practices as well as with The Royal College of Anaesthetists' recommendations at that time. It is apparent that the duration of intensive supervision of new anaesthetic trainees has increased over the last 25 years. This study assesses these changes in order to evaluate whether or not these reforms have achieved their intended outcomes.
The cardiovascular response to insertion of the intubating laryngeal mask airway
Authors: Choyce A. , Avidan M. S. , Harvey A. , Patel C. , Timberlake C. , Sarang K. , Tilbrook L.
Published: March 2003

Sixty‐one patients received a standardised anaesthetic and were randomly assigned to three groups: tracheal intubation via direct laryngoscopy, tracheal intubation via an intubating laryngeal mask airway with immediate removal of the device, and tracheal intubation via an intubating laryngeal mask airway with delayed removal. The cardiovascular response to intubation was of a similar magnitude in all groups, although delayed removal of the intubating laryngeal mask airway was associated with a second pressor response. Norepinephrine changed significantly over time following direct laryngoscopy and following immediate removal of the intubating laryngeal mask airway, but not after delayed removal. The findings of this study do not support using the intubating laryngeal mask instead of direct laryngoscopy purely to decrease the response to intubation.
Patient feedback on the anaesthetist's performance during the pre‐operative visit
Authors: Carnie J.
Published: March 2003

Summary A questionnaire was devised from guidelines published by the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland for the conduct of the pre‐operative interview and conduct of anaesthesia. The responses to the questionnaire formed the basis of an accumulative record of patient feedback on individual anaesthetist's performance and used as one component of annual appraisal. The median ‘desired answer’ and ‘overall dissatisfaction’ percentages, and the ‘desired : undesired answer’ ratio for consultants and non‐training grade doctors from 835 patients at a large Acute District General Hospital were 92%, 0.6% and 12 : 1, respectively.
Percutaneous tracheostomy with the Blue Rhino™ technique: presentation of 100 consecutive patients
Authors: Fikkers B. G. , Briedé I. S. , Verwiel J. M. M. , Van Den Hoogen F. J. A.
Published: March 2003

Summary We assessed the peri‐operative, early and late complications in 100 percutaneous tracheostomies performed with the Blue Rhino™ kit. The success rate was 98%. Peri‐operative complications occurred in 30 patients. Six major complications occurred; these included bleeding which required surgical exploration (n = 3), and pneumothoraces (n = 2) and one false passage. Cannula insertion was made easier by blunt dissection of the cervical tissues anterior to the trachea. The median duration of the procedure was 8.5 min, which is significantly longer than other authors' results. Only one major complication occurred while the patient was cannulated (serious bleeding requiring exploration). Finally, in a single patient a tracheal stenosis occurred as a major late complication which eventually was treated by a successful tracheal resection. Percutaneous tracheostomy with the Blue Rhino™ kit is safe with a low incidence of major complications.
The effect of intra‐operative video on patient anxiety
Authors: Man A. K. Y. , Yap J. C. M. , Kwan S. Y. , Suen K. L. , Yip H. S. , Chen P. P.
Published: March 2003

Summary We conducted a randomised controlled study to evaluate whether watching video compact discs intra‐operatively using a liquid crystal display (LCD) unit decreased anxiety. Forty‐four patients undergoing elective surgery under regional anaesthesia were assigned to either the LCD or control group. Anxiety was measured using the Chinese version of the State‐Trait Anxiety Inventory (STAI) and visual analogue score (VAS). The mean (SD) anxiety trait scores were 46.15 (6.28) and 46.40 (7.32) in the control and LCD groups, respectively. The state anxiety of the LCD group [35.50 (7.96)] measured immediately postoperatively was significantly lower than the control group [41.50 (9.02); p = 0.03]. The median (range) reduction in VAS anxiety score was not significantly greater in the LCD group [20 (−20 to 80) mm] compared with the control group [12.5 (−70 to 60) mm]. Watching video intra‐operatively reduces patient anxiety as measured by the STAI.
Changes in cerebral oxygenation in children undergoing surgical repair of ventricular septal defects
Authors: Morimoto Y. , Niida Y. , Hisano K. , Hua Y. , Kemmotsu O. , Murashita T. , Yasuda K.
Published: March 2003

Summary There have been few published studies on changes in cerebral oxygenation during paediatric cardiac surgery as measured by conventional near‐infrared spectroscopy. We studied changes in cerebral oxygenation in 16 children undergoing surgical repair of ventricular septal defects. Fifteen of the patients showed similar patterns of changes: brain tissue concentrations of oxyhaemoglobin decreased significantly during cardiopulmonary bypass, whereas there was no significant change in brain tissue concentrations of deoxyhaemoglobin. In the remaining patient, who suffered decreased blood flow to the lower body during surgery, the pattern of changes was different to that of the other subjects. This patient suffered postoperative respiratory and renal failure. This study suggests that conventional near‐infrared spectroscopy may be useful for clinical monitoring during ventricular septal defect repair.
Pre‐operative screening: Criteria for referring to anaesthetists
Authors: Hilditch W. G. , Asbury A. J. , Crawford J. M.
Published: March 2003

Summary Nurses assess patients pre‐operatively using screening questionnaires and locally‐developed protocols. Our objectives were to determine which questions might identify patients who should be seen by an anaesthetist before the day of surgery. A review of the literature and a preliminary questionnaire to establish questions to be tested was followed by a modified, two‐round Delphi questionnaire to determine the level of agreement by anaesthetists. There was agreement for referring patients who gave a positive response to questions that query: restricted exercise tolerance; previous anaesthetic problems; family history of anaesthetic problem; pathology affecting neck movement; angina; arrhythmia; heart failure; asthma; epilepsy; insulin‐dependent diabetes mellitus; liver disease and unspecified kidney disease. There was equivocal agreement on questions that report a myocardial infarction over one year ago, cerebrovascular accident, non insulin‐dependent diabetes mellitus and thyroid disease. Nurses should use these criteria during pre‐operative assessment to decide the timing of evaluation by an anaesthetist.
Mechanisms contributing to the vaso‐active effects of prilocaine in human skin
Authors: Newton D. J. , Sur E. L. , Khan F. , McLeod G. A. , Belch J. J. F.
Published: March 2003

Summary We investigated the roles of the endothelial nitric oxide and cyclo‐oxygenase pathways in mediating the vasoactivity of prilocaine in the skin. We injected prilocaine 1% intradermally into forearm skin of 10 healthy, male subjects. Nitric oxide synthesis was inhibited at a second site by co‐injecting prilocaine with l‐NAME 1%. We then repeated the injections while blocking the cyclo‐oxygenase pathway with aspirin (4 × 600 mg). We measured blood flow responses to the injections using laser Doppler imaging. We found that, after the traumatic effects of injection had subsided, l‐NAME reduced the vascular response to prilocaine by a third (p = 0.012), indicating an influence specifically on the drug response. Aspirin had no effect on the response (p = 0.588). We conclude that the vasoactive effects of prilocaine in human skin are mediated partly through the release of endothelial nitric oxide and, although other mechanisms might also be involved, the cyclo‐oxygenase pathway does not appear to play a role.
The need for a regional weaning centre, a one‐year survey of intensive care weaning delay in the Northern Region of England*
Authors: Robson V. , Poynter J. , Lawler P. G. , Baudouin S. V.
Published: March 2003

Summary Over a period of one year, a weekly telephone survey identified 161 stable patients with weaning delay (defined as patients ventilated for at least 6 h per day for more than 2 weeks) in intensive care units in the Northern Region of England. Their median age was 69 years (range 21–88 years). Sixty patients (37%) were admitted with medical conditions, 89 (55%) were postoperative patients, whereas 12 (8%) were surgical but required non‐operative admission. One hundred and thirty (89%) were weaned and discharged from the intensive care unit during the year. Twenty‐two (14%) died and two were transferred to the home ventilation service. Seven patients remained ventilated in intensive care at the end of the study period. Twenty patients (12%) required more than 28 days of respiratory support. These patients occupied on average 6.0% of available intensive care unit beds in the region. This study suggests that in the Northern Region of England there are a significant number of stable but ventilator‐dependent patients occupying intensive care beds.
Nasotracheal intubation for head and neck surgery
Authors: Hall C. E. J. , Shutt L. E.
Published: March 2003

Nasotracheal intubation offers the head and neck surgeon more scope for surgical manoeuvre in operations of the mouth, pharynx, larynx and also the neck. Concern over the complications of using this route of intubation and lack of training may be limiting its use. A thorough knowledge of the anatomy, benefits of using nasal vasoconstrictors and attention to technique are prerequisites to maintaining the skill. This article reviews each of these topics and aims to encourage the appropriate use of nasotracheal intubation in current practice.
The impact of Acinetobacter baumannii in the intensive care unit
Authors: Theaker C. , Azadian B. , Soni N.
Published: March 2003

Summary Acinetobacter baumannii is a significant problem in critically ill patients. It is widespread, can colonise patients quickly and causes virulent infections. However, its overall impact on morbidity and mortality in the critically ill remains unmeasured. This study was designed to investigate A. baumannii colonisation and infection rates in a critically ill population over an 18‐month period. Twenty‐seven patients from a population of 347 were identified as having A. baumannii. Sixteen were colonised, whereas 11 were infected. Eleven of the 27 patients with A. baumannii died (41%). Of these, eight were colonised and three were infected. In the same period, 320 patients did not have A. baumannii and their mortality rate was 20% (n = 64). The mortality rate of patients with A. baumannii was significantly higher than that of patients without infection.
Reconstructing orogenic exhumation histories using synorogenic detrital zircons and apatites: an example from the Betic Cordillera, SE Spain
Authors: Lonergan Lidia , Johnson Christopher
Published: March 2003

Fission track thermogeochronology using detrital apatite and zircon from a synorogenic foreland basin on the northern margin of the Betic Cordillera Internal Zone is used to reconstruct the cooling and unroofing history of the sediment source areas in the Oligo‐Miocene mountain belt. Previously, a heavy mineral study on the same sedimentary rocks showed that progressively deeper tectonometamorphic units were being unroofed during the latest Oligocene to middle Miocene at a minimum rate of 3 km Myr−1. The fission track data have further constrained the exhumation history showing that the structurally highest (i.e. shallowest) parts of the mountain belt (Malaguide Complex) cooled relatively slowly during the latest Oligocene–Aquitanian, while the deeper metamorphic units (Alpujarride Complex) cooled at much higher rates (up to 300 °C Myr−1) during the Burdigalian–Langhian. These fast cooling rates from synorogenic detritus are consistent with cooling rates calculated previously for the deeper parts of the early Miocene orogenic belt, using39Ar–40Ar dating of muscovite, biotite and amphibole from basement metamorphic rocks. Rapid cooling in the early Miocene, which commenced at ≈21 Ma, is attributed to the change in process from erosional to tectonic denudation by orogen‐scale extension within the eastern Betic Cordillera.
Stability of output fluxes of large rivers in South and East Asia during the last 2 million years: implications on floodplain processes
Authors: Métivier  , Gaudemer
Published: March 2003

We compare the present‐day sediment discharge (solid phase) of some of the largest rivers in Asia to the average discharge deduced from the mass accumulated in several sedimentary basins during the Quaternary. There is a very good correlation, especially for the largest rivers: the Ganges–Brahmaputra, the Changjiang, the Huanghe and, to a lesser extent, the Indus and the Zhujiang. This suggests that present‐day average discharge at the outlet has remained constant throughout the Quaternary at least for very large rivers (drainage area of the order of 105–106 km2). This, in turn, suggests either that continental denudation of large Asian catchments has remained on average constant, implying a strong tectonic control on erosion during the Quaternary, or that the river network has the ability to buffer changes in hillslope erosion or in sea‐level in order to conserve the total discharge at the outlet. We show how this buffering capacity relies on the characteristic reaction time‐scale of Asian alluvial plains (of the order of 105–6 years), that is, much higher than the time‐scales of the Quaternary climate oscillations (of the order of 104 years). A short‐term perturbation originating in hillslopes will be diluted by the floodplain. At the outlet the signal should have a longer time span and a smaller amplitude. In the same manner, an alluvial plain should not instantaneously react to a 104‐year sea‐level drop because of its inertia. Along with long‐term tectonic control we infer this buffering to be the main cause for the average constancy of sediment yield of large Asian rivers during the Quaternary.
Numerical forward modelling of peritidal carbonate parasequence development: implications for outcrop interpretation
Authors: Burgess P. M. , Wright V. P. , Emery D.
Published: March 2003

The mechanisms responsible for formation of peritidal parasequences have been a focus of debate between proponents of contrasting autocyclic and allocyclic models. To contribute to this debate a three‐dimensional numerical forward model of carbonate production, transport and deposition has been developed. Shallowing‐upward parasequences are produced in the model via carbonate island formation and progradation, with an element of self‐organization, and no external forcing. These autocyclic parasequences have characteristics comparable with peritidal parasequences observed in outcrop. Modelled parasequence thickness and duration depend primarily on subsidence rate and sediment transport rate, illustrating the significance of sediment flux in formation of peritidal parasequences. Adding an element of stochastic variation of sediment transport rate and transport path leads to formation of nonuniform‐thickness parasequences that generate Fischer plots showing apparent hierarchies similar to those often interpreted as evidence of eustatic forcing. The model results do not rule out allocylic mechanisms, but suggest that shoreline and island progradation are also plausible mechanisms to create variable‐thickness, shallowing‐upward peritidal parasequences and should be considered in interpretations of such strata.
Normal faulting, extension and uplift in the outer thrust belt of the central Apennines (Italy): role of the Caramanico fault
Authors: Ghisetti F. , Vezzani L.
Published: March 2003

The outer Adriatic zones of the central Apennines (Italy) provide good conditions for analysing geometry and kinematics of the earliest normal faults, superposed onto the thrust belt. During the latest stages of thrusting onto the Adriatic foreland (late Pliocene–early Pleistocene), the outermost imbricates of the thrust belt were subjected to normal faulting, coeval with differential uplift. Crosscutting normal faults get younger towards the foreland, thus the easternmost normal faults record the latest stages of fault propagation and growth. The Caramanico fault, on the western flank of Mt. Maiella, is the largest outcropping normal fault of the outer zones. This high‐angle fault (dip > 70°) has cumulative offsets ≤ €4.2 km, and propagated with slip rates of 2.6 mm/year in a short time interval (≤ 1.6 Ma), concomitant with intense uplift of Mt. Maiella. In contrast with normal faults in a more internal position, the Caramanico fault maintains a high‐angle planar geometry, and does not reach the major basal detachment of the thrust belt. Thus the fault did not cause large extensional displacements; its major role was rather to accommodate ongoing components of vertical uplift of the overthickened thrust wedge. Downfaulting of the thrust belt on the western flank of Mt. Maiella represents the youngest end member of the same processes that have operated since 11 Ma in the Tyrrhenian hinterland, where large extensional strains and crustal thinning of the orogenic belt were achieved by long‐lasting activity of listric normal faults detached at lower crustal depths.
Insulating effect of coals and organic rich shales: implications for topography‐driven fluid flow, heat transport, and genesis of ore deposits in the Arkoma Basin and Ozark Plateau
Authors: Nunn J.A. , Lin G.
Published: March 2003

ABSTRACT Sedimentary rocks rich in organic matter, such as coal and carbonaceous shales, are characterized by remarkably low thermal conductivities in the range of 0.2–1.0 W m−1 °C−1, lower by a factor of 2 or more than other common rock types. As a result of this natural insulating effect, temperature gradients in organic rich, fine‐grained sediments may become elevated even with a typical continental basal heat flow of 60 mW m−2. Underlying rocks will attain higher temperatures and higher thermal maturities than would otherwise occur. A two‐dimensional finite element model of fluid flow and heat transport has been used to study the insulating effect of low thermal conductivity carbonaceous sediments in an uplifted foreland basin. Topography‐driven recharge is assumed to be the major driving force for regional groundwater flow. Our model section cuts through the Arkoma Basin to Ozark Plateau and terminates near the Missouri River, west of St. Louis. Fluid inclusions, organic maturation, and fission track evidence show that large areas of upper Cambrian rocks in southern Missouri have experienced high temperatures (100–140 °C) at shallow depths (< 1.5 km). Low thermal conductivity sediments, such as coal and organic rich mudstone were deposited over the Arkoma Basin and Ozark Plateau, as well as most of the mid‐continent of North America, during the Late Palaeozoic. Much of these Late Palaeozoic sediments were subsequently removed by erosion. Our model results are consistent with high temperatures (100–130 °C) in the groundwater discharge region at shallow depths (< 1.5 km) even with a typical continental basal heat flow of 60 mW m−2. Higher heat energy retention in basin sediments and underlying basement rocks prior to basin‐scale fluid flow and higher rates of advective heat transport along basal aquifers owing to lower fluid viscosity (more efficient heat transport) contribute to higher temperatures in the discharge region. Thermal insulation by organic rich sediments which traps heat transported by upward fluid advection is the dominant mechanism for elevated temperatures in the discharge region. This suggests localized formation of ore deposits within a basin‐scale fluid flow system may be caused by the juxtaposition of upward fluid discharge with overlying areas of insulating organic rich sediments. The additional temperature increment contributed to underlying rocks by this insulating effect may help to explain anomalous thermal maturity of the Arkoma Basin and Ozark Plateau, reducing the need to call upon excessive burial or high basal heat flow (80–100 mW m−2) in the past. After subsequent uplift and erosion remove the insulating carbonaceous layer, the model slowly returns to a normal geothermal gradient of about 30 °C km−1.