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Biomedical subjects

J E Hall

Publications and source records attributed to J E Hall.

At least 19 recordsLinked to original sources
PubMed2007

Predictive value of IL-18 and SC5b-9 for neurocognitive dysfunction after cardiopulmonary bypass.

BACKGROUND: Neurological injury after cardiopulmonary bypass (CPB) continues to be a major problem after cardiac surgery. The aim of this study was to investigate the predictive value of Interleukin-18 (IL-18) and SC5b-9 as biochemical markers of neurocognitive dysfunction after cardiac surgery. METHODS: A total of 30 patients undergoing elective cardiac surgery using CPB were recruited. Blood samples were obtained for IL-18 and SC5b-9 concentrations before induction, 24, 48, 72, 96 and 120 h post-CPB and 6 weeks after operation. In addition, patients underwent a standard battery of neuropsychometric tests before operation and at day 5 and 6 weeks after operation. RESULTS: Serum concentration of IL-18, but not SC5b-9, was significantly different between patients with and without neurocognitive dysfunction; serum IL-18 concentration significantly increased in patients with neurocognitive dysfunction (P = 0.018). Neurological outcome was significantly dependent on peak difference in IL-18 concentration at day 5 (P = 0.033), but not on peak difference in SC5b-9 concentration (P = 0.16). Eight patients had neurocognitive dysfunction at day 5 and three had neurocognitive dysfunction at 6 weeks. In a very small number of patients, no significant association was demonstrated between IL-18 or SC5b-9 concentrations and neurocognitive dysfunction at 6 weeks. CONCLUSIONS: IL-18 has the potential as a useful marker of neurological dysfunction, requiring further investigation.

Aged↗
PubMed2007

The use of nitrous oxide in paediatric anaesthetic practice in the United Kingdom: a questionnaire survey.

Nitrous oxide pollution is common in paediatric anaesthetic practice. A questionnaire was sent to all UK members of the Association of Paediatric Anaesthetists requesting details of three areas of their paediatric practice relating to nitrous oxide: attitudes to its use; current usage; and availability of alternatives. Replies were received from 296 (68%) consultants. Of these, 169 (57%) stated that their use of nitrous oxide had decreased over the last 5 years. One hundred and fifty-eight (54%) considered theatre pollution a problem in paediatric anaesthesia. One hundred and sixty-nine (57%) reported that in normal circumstances potential deleterious effects on patients influenced their use of nitrous oxide, whilst only 70 (24%) felt potential effects on staff influenced usage. Fifty-five (18%) felt there should be some restriction in the availability of nitrous oxide.

Anesthesia↗
PubMed2007

Assessing the efficacy of HME filters at preventing contamination of breathing systems.

Breathing system filters are intended to prevent cross-infection during anaesthesia. However, there is a lack of information on whether filters prevent contamination of the breathing system by the patient. We measured the contamination of 235 used filters of four different types obtained from operating theatres: two pleated hydrophobic (BB25M and BB22/15M, Pall Medical, Portsmouth, UK) used for adult patients and two electrostatic (355/5430 Hygroboy and 355/5427 Hygrobaby, Tyco Healthcare, Gosport, UK) used for paediatric patients. The filters were swabbed over their internal surfaces on both the patient and the machine sides and these were assessed with the use of adenosine triphosphate bioluminescence. Contamination was present on the machine side of 20 (9%) filters. Current standards for testing of filters has no set "pass" level and is performed in the laboratory setting. Bioluminescence may be used in the clinical setting to elucidate factors that might increase the chance of cross-contamination between patients.

Adenosine Triphosphate↗
PubMed2007

Minimum and optimum light output of Macintosh size 3 laryngoscopy blades: a manikin study.

Illumination provided by laryngoscope blades varies widely. It is not known what the optimum level of illumination should be during laryngoscopy. So far, no published standards exist for light intensity provided by laryngoscopes. Fifty anaesthetists were recruited to perform laryngoscopy on a manikin with three different laryngoscopes attached to a variable voltage supply. Anaesthetists were asked to find the minimum and optimum level of light they would wish to have for intubation. This study demonstrated that anaesthetists can see the larynx at very low light levels. The optimum level was significantly greater than the minimum level. The vacuum bulb laryngoscopes provides a significant lower light output than halogen and xenon laryngoscopes. There is a large variation in illumination requirements amongst anaesthetists which may make setting standards difficult. A brighter laryngoscope, as suggested by some manufacturers, may not necessarily be a better one.

Adult↗
PubMed2006

A comparison of the use of Trachlight and Eschmann multiple-use introducer in simulated difficult intubation.

BACKGROUND AND OBJECTIVE: The Eschmann multiple-use introducer is widely used in the management of difficult intubations. Transillumination of the neck is less commonly used. We conducted a randomized crossover study comparing the Trachlight lightwand and Eschmann multiple-use introducer in simulated difficult intubation. METHODS: Sixty-four healthy patients were studied using a standard anaesthetic and full muscle relaxation assessed by train of four. A Macintosh laryngoscope was then inserted and then lowered to simulate a Grade 3 view. Tracheal placement was attempted with both Trachlight lightwand and Eschmann multiple-use introducer in a randomized order. Anaesthetists placing the devices had extensive experience with the Eschmann multiple-use introducer, but only 15 previous uses of the Trachlight. Success rates and time for tracheal placement were recorded. RESULTS: The Eschmann multiple-use introducer and Trachlight were successfully placed in 96.8% and 93.7%, respectively (n.s.). Mean (SD) time to intubation for Eschmann multiple-use introducer and Trachlight were 15(6) and *21(13), respectively (*P < 0.001). CONCLUSION: The Trachlight is a potentially useful alternative to the Eschmann multiple-use introducer in difficult intubation.

Female↗
PubMed2006

Polycystic ovarian morphology in normal women does not predict the development of polycystic ovary syndrome.

CONTEXT: Polycystic ovarian morphology (PCOM) is present in 25% of normal women in the absence of polycystic ovary syndrome (PCOS); however, the natural history of PCOM is unknown. OBJECTIVE: We hypothesized that the presence of PCOM predisposes the development of PCOS. DESIGN: The study was a longitudinal follow-up study over 8.2 +/- 5.2 yr (mean +/- sd; range 1.7-17.5 yr). SETTING: The study took place in an outpatient setting. SUBJECTS: Women who took part in a previous study as a normal control and had an ultrasound examination (n = 40) participated. INTERVENTION: Subjects underwent an interval menstrual history, physical exam, blood sampling, and repeat ultrasound in the follicular phase. MAIN OUTCOME MEASURE: Development of PCOS was diagnosed by irregular menses and hyperandrogenism, in the absence of other disorders. Changes in ovarian morphology over time were evaluated. RESULTS: At the baseline visit, 23 women (57.5%) had PCOM and 17 (42.5%) had normal ovarian morphology. One subject with PCOM developed irregular menses and presumptive PCOS. Eleven subjects with PCOM no longer met the criteria for PCOM at follow-up. There was no factor that predicted the change to normal ovarian morphology at the follow-up visit. CONCLUSIONS: These data suggest that PCOM in women with regular ovulatory cycles does not commonly predispose the development of PCOS. Although it is unusual to develop PCOM if the ovaries are normal on first assessment, ovaries in women with PCOM no longer meet the criteria for PCOM in approximately half of cases over time.

Adult↗
PubMed2006

Control of estradiol secretion in reproductive ageing.

BACKGROUND: Estradiol (E(2)) concentration is preserved in older reproductive-aged women despite a decrease in follicle number and androstenedione (AD) levels. We hypothesized that increased aromatase activity accounts for E(2) preservation in older women. METHODS: Older (36-46 years; n = 11) and younger (21-35 years; n = 10) women with 25- to 35-day menstrual cycles participated in a parallel design study. Daily blood samples were drawn starting at menses, and recombinant human FSH (rhFSH), 150 IU, was administered when the dominant follicle's diameter was > or =16 mm. FSH, LH, E(2), estrone (E(1)), AD and the AD/E(1) ratio were compared. RESULTS: E(2) and E(1) concentrations and the E(1)/E(2) ratio were similar across the follicular phase in older compared with younger women, whereas AD and the AD/E(1) ratio were lower. Older women had higher FSH concentrations in the early follicular phase and fewer small follicles. RhFSH-stimulated changes in E(1) were similar between older and younger subjects despite the smaller number of follicles. CONCLUSIONS: These findings suggest that E(2) secretion is maintained by increased aromatase function in older compared with younger reproductive-aged women, whereas there is no apparent difference in 17beta-hydroxysteroid dehydrogenase activity. The increased aromatase is probably driven by increased FSH in the early follicular phase and compensates for the decreased follicle number in older reproductive-aged women.

Adult↗
PubMed2006

A comparison of the Soft Seal disposable and the Classic re-usable laryngeal mask airway.

Many new supraglottic airway devices have been recently introduced, their development motivated by the need for a single-use equivalent to the original re-usable laryngeal mask airway. We performed a randomised cross-over study in spontaneously breathing patients comparing the re-usable Laryngeal Mask Airway-Classic (LMA) and the disposable Soft Seal Laryngeal Mask in sizes 3, 4 and 5. Sixty patients had an LMA and a disposable laryngeal mask placed in random order. The primary outcome was first attempt insertion success rate. Ease of insertion was similar in both groups and there was no difference in first attempt success rates (96% with LMA and 92% with disposable laryngeal mask). The disposable laryngeal mask required significantly less air to inflate the cuff to produce a seal (10 [10-25] ml with disposable laryngeal mask and 15 [10-30] ml with laryngeal mask) and the cuff pressure produced was significantly lower (35 [20-80] cmH(2)O with disposable laryngeal mask and 75 [20-120] cmH(2)O with LMA). Data are median and range. We conclude that the disposable laryngeal mask is an acceptable alternative to the re-usable LMA.

Adult↗
PubMed2006

Haemodynamic effects of the prone position: a comparison of propofol total intravenous and inhalation anaesthesia.

The haemodynamic changes of the prone position were investigated in 40 ASA I-II patients undergoing lumbar spine surgery. Patients were randomly assigned, following propofol intravenous induction, to receive maintenance of anaesthesia using either isoflurane 1-1.2% in air or target controlled propofol 3 microg.ml(-1) infusion. Measurements of non-invasive blood pressure, heart rate and cardiac output were made in the supine position. The patient was then turned prone onto a Montreal pattern mattress and measurements repeated. Cardiac output measurements were made using a non-invasive cardiac output monitor. We found a significant reduction in cardiac index in both groups and a significantly greater change with propofol compared to isoflurane on turning supine to prone (CI change 0.4 vs 0.7 l.min(-1).m(-2) p = 0.001 and SVRI change 89 vs 177 dyne.s(-1).cm(-5), p = 0.041). We conclude that turning healthy patients prone produces a clinically significant reduction in cardiac output, the change being greater during maintenance of anaesthesia using propofol compared to isoflurane.

Adolescent↗
PubMed2006

A comparison of the Seeing Optical Stylet and the gum elastic bougie in simulated difficult tracheal intubation: a manikin study.

Management of the difficult airway is one of the major challenges that anaesthetists face. The flexible fibreoptic scope is widely available but its use requires a level of skill, training and continued practice that is not universally found in all anaesthetists, particularly trainees. The Seeing Optical Stylet is a new, semirigid fibreoptic stylet 'scope. We compared the Seeing Optical Stylet with a gum elastic bougie in a simulated Cormack and Lehane Grade 3 laryngoscopy in a manikin. Forty-four anaesthetists were timed while intubating the manikin's trachea with both devices. The mean (SD) time taken with the Seeing Optical Stylet was 20.8 (9.3) s and with the bougie 30 (19.8) s (p = 0.001). Oesophageal intubation occurred six times with the bougie but did not occur with the Seeing Optical Stylet (p = 0.011). We conclude that the Seeing Optical Stylet may be superior to the bougie in difficult tracheal intubation. We feel that the results of this manikin trial are sufficiently encouraging to proceed to a clinical trial in patients.

Clinical Competence↗
PubMed2006

The pressure required to force liquid through breathing system filters.

Liquid in the form of sputum and condensation may be forced through a breathing system filter if sufficient pressure is applied to the filter layer, with the potential for cross-infection. Twenty-three different breathing system filters (12 adult, 11 paediatric) were assessed to determine the pressure causing liquid penetration. Five samples of each were tested by connecting the ventilator end of a breathing system filter to a water-filled U-tube and reservoir. The reservoir was positioned so that the water surface was level with the filter layer and raised until liquid appeared through the filter layer on the patient side and the water-column height recorded. There were substantial differences in performance between models. Liquid penetration occurred at lower pressures for adult electrostatic than adult pleated filters: median [IQR] 1.18 [1.08- 1.32] and 8.04 [4.27-12.80] kPa, respectively, p < 0.0001. Liquid penetration occurred at similar pressures in paediatric electrostatic filters (0.98 [0.74-1.32] kPa) compared to adult electrostatic filters.

Adult↗
PubMed2006

Flexibility and light emission of disposable paediatric Miller 1 laryngoscope blades*.

With the emergence of Creutzfeldt-Jakob disease and the discovery of prions in tonsillar material, there has been an increase in the number of available disposable laryngoscope blades. This has led to non-conformity over many aspects of blade design. Miller 1 disposable blades have been produced in both metal and plastic and appear to have different properties of rigidity. We examined the rigidity of 11 disposable Miller 1 blades in three different axes of force. There was a significant difference in flexibility between metal and plastic blades in both primary and torsional axis (p = 0.006). We also studied the blades' light intensity and angle of light emission, finding up to an eightfold difference in the level of illumination provided at a distance of 10 mm from the tips of the blades. The area of maximal illumination varied, with some blades providing narrow beams of light, and others provided a more dispersed field of illumination. In addition, the angle of maximal illumination varied between the blade types from a central position to one directed to the right-hand side.

Disposable Equipment↗
PubMed2006

The use of impedance respirometry to confirm tracheal intubation in children.

Accidental oesophageal intubation can occur in children and is a cause of morbidity and mortality. This study investigated the use of impedance respirometry to determine tracheal tube position in children aged 1-10 years. Eighty children were recruited and, after induction of anaesthesia, two identical tracheal tubes were inserted: one into the trachea and one into the oesophagus. The breathing system was attached to one of the tubes chosen at random. A blinded observer was asked to identify the position of the tube within six breaths using impedance respirometry. The positions of 76 out of 80 tubes were correctly identified. Of those incorrectly identified, one was in the trachea and three were in the oesophagus. The sensitivity of the test was 0.975 and the specificity 0.925. The median number of breaths needed to identify the position of the tubes was 2.0 for both groups. This is not a perfect technique in the population studied but when used with other methods of tracheal tube position identification, its use could decrease the time taken to identify incorrect placement.

Child↗
PubMed2006

Nicotinic acetylcholine receptors on basophils and mast cells.

Anaphylaxis in response to drugs administered during anaesthesia is a rare but potentially catastrophic event. The anaesthetic drugs most commonly associated with anaphylaxis are neuromuscular blocking agents. As these drugs act on the nicotinic acetylcholine receptor of the neuromuscular junction, potentiation of anaphylaxis by a nicotinic receptor on basophils and mast cells is plausible. The aim of this study was to investigate whether nicotinic acetylcholine receptors are present on a human basophil and mast cell lines as their presence may suggest a mechanism of associated anaphylaxis. Nicotinic receptors were demonstrated on a basophil and a mast cell line using an alpha-bungarotoxin-fluorescein conjugate by flow cytometry and by both conventional and confocal microscopic techniques. The identity of this receptor was confirmed by reverse transcriptase PCR and quantitative PCR.

Basophils↗
PubMed2005

In vitro metabolism of an orally active O-methyl amidoxime prodrug for the treatment of CNS trypanosomiasis.

A new aza-analogue of furamidine, 6-[5-(4-amidinophenyl)-furan-2-yl]nicotinamidine (DB820), has potent in vitro antitrypanosomal activity; however, it suffers from poor oral activity because of its positively charged amidine groups. The dimethoxyamidine prodrug of DB820, N-methoxy-6-{5-[4-(N-methoxyamidino)phenyl]-furan-2-yl}-nicotinamidine (DB844), has potent oral activity in mouse models of both early-stage and CNS African trypanosomiasis. Metabolism of DB844 in human liver microsomes (HLM) was investigated using liquid chromatography-mass spectrometry (LC-MS/MS). The metabolism of DB844 in HLM was NADPH-dependent and resulted in the production of eight metabolites over a 90?min incubation. O-Demethylation and N-dehydroxylation reactions resulted in the metabolic conversion of DB844 to its active DB820 metabolite. Chromatographic conditions used for LC-MS analysis allowed for the separation and identification of all metabolites including positional isomers. Demethylation of either the phenyl or pyridine side of DB844 (DB844 m/z 366.2) resulted in the production of two metabolites (M1A, M1B), each with a molecular ion of m/z of 352.3 and MS(2) fragments of 288.1, 305.2, 321.2 and 335.2. However, the intensities of the MS(2) fragments were different among the two isomeric metabolites, and comparison to an authentic standard allowed for the structural determination of each metabolite. The isomeric metabolites M2A and M2B, resulting from amidoxime reductions of M1A and M1B, were also chromatographically separated and had distinguishable MS(2) profiles that allowed for their structural assignments when compared to an authentic standard. The di-amidoxime product resulting from O-demethylation of either side of DB844 was also identified as an abundant metabolite during microsomal incubations. The active antitrypanosomal metabolite, DB820, was the last metabolite to be formed and thus provides evidence that DB844 may effectively be metabolized to its active metabolite in vivo.

Administration, Oral↗