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Biomedical subjects

J Bannister

Publications and source records attributed to J Bannister.

At least 19 recordsLinked to original sources
PubMed2004

Disparity of autonomic control in type 2 diabetes mellitus.

AIMS/HYPOTHESIS: Acute insulinaemia activates the sympathetic drive in a nonuniform manner. The extent and nature of such activation in type 2 diabetic patients who do not have neuropathy have not yet been addressed despite evidence relating sympathetic activation to cardiovascular risk. We planned to determine the magnitude and extent of the sympathetic drive and its reflex responses in patients with type 2 diabetes and fasting hyperinsulinaemia. METHODS: We measured resting muscle sympathetic nerve activity (MSNA) as the mean frequency of multi-unit bursts and single unit muscle sympathetic nerve activity (s-MSNA) in 17 overweight patients with type 2 diabetes and two matched normal control groups comprising 17 overweight and 16 normal-weight subjects. We also tested the MSNA and s-MSNA responses to cold pressor and isometric hand-grip tests, along with the effect of sympatho-vagal balance on heart period variability. RESULTS: Both MSNA and s-MSNA in the group with type 2 diabetes (66+/-3.5 bursts/100 beats and 78+/-4.5 impulses/100 beats) were greater (at least p<0.0001) than in the overweight control group (42+/-2.6 bursts/100 beats and 48+/-3.4 impulses/100 beats) and normal-weight control group (43+/-6.2 bursts/100 beats and 51+/-7.1 impulses/100 beats), though the three groups had similar reflex responses, baroreflex sensitivity and sympatho-vagal balance controlling the heart period. CONCLUSIONS/INTERPRETATION: The patients with type 2 diabetes had no evidence of impaired reflex or autonomic control of heart period variability at a time when there was central sympathetic activation to the periphery. Furthermore, being overweight itself was not associated with sympathetic activation.

Action Potentials↗
PubMed2004

Rhetoric and reality on acute pain services in the UK: a national postal questionnaire survey.

BACKGROUND: The study aimed to explore the extent to which NHS acute pain services (APSs) have been established in accordance with national guidance, and to assess the degree to which clinicians in acute pain management believe that these services are fulfilling their role. METHODS: A postal questionnaire survey addressed to the head of the acute pain service was sent to 403 National Health Service hospitals each carrying out more than 1000 operative procedures a year. RESULTS: Completed questionnaires were received from 81% (325) of the hospitals, of which 83% (270) had an established acute pain service. Most of these (86%) described their service as Monday-Friday with a reduced service at other times; only 5% described their service as covering 24 hours, 7 days a week. In the majority of hospitals (68%), the on-call anaesthetist was the sole provider of out of hours services. Services were categorized by respondents as thriving (30%), struggling to manage (52%) or non-existent (17%). There was widespread agreement (> or =85%) on the principles that should underpin acute pain services, and similar agreement on the need for better organizational approaches (95%) rather than new treatments and delivery techniques (19%). CONCLUSIONS: More than a decade since the 1990 report Pain after Surgery, national coverage of comprehensive acute pain services is still far from being achieved. Despite wide consensus about the problems, concrete solutions are proving hard to implement. There is strong support for a two-fold response: securing greater political commitment to pain services and using organizational approaches to address current deficits.

Attitude of Health Personnel↗
PubMed2001

Postoperative pain relief using thoracic epidural analgesia: outstanding success and disappointing failures.

Six hundred and forty patients received epidural analgesia for postoperative pain relief following major surgery in the 6-year period 1993-1998. Although satisfactory pain relief was achieved in over two-thirds of patients for a median duration of 44 h after surgery, one-fifth of patients (133 individuals) still experienced poor pain relief. Almost one out of three patients (194 individuals) had a problem with their epidural. Eighty-three patients (13%) suffered a technical failure and 84 (13%) patients had their epidurals removed at night time when pain-free because of pressure on beds. Seven patients had their epidural replaced and subsequently experienced excellent pain relief for a median of 77 h. Lack of resources prevented a further 480 patients from receiving the potential benefits of epidural analgesia. These results would suggest that the practical problems of delivering an epidural service far outweigh any differences in drug regimens or modes of delivery of epidural solutions.

Aged↗
PubMed2000

Antiarrhythmic management and implantable defibrillator use in survivors of prehospital cardiac arrest without myocardial infarction in West Yorkshire.

OBJECTIVE: To explore the current use of secondary preventive treatment in survivors of out of hospital cardiac arrest without myocardial infarction (primary ventricular tachycardia/ventricular fibrillation (VT/VF)) in West Yorkshire, and assess the implications of recent studies on the benefits of implantable cardioverter-defibrillators (AICD) in this context. DESIGN: Retrospective analysis of an ambulance service based database of outcome after resuscitation of out of hospital cardiac arrest and the Leeds AICD implantation database. MAIN OUTCOME MEASURES: Mortality, rate of referral for specialist investigation, antiarrhythmic treatment. RESULTS: Twelve month mortality following successful discharge after primary VF arrest was 15%. Of 53 patients with primary VF/VT, 29 apparently did not see a cardiologist during the initial admission. Amiodarone was the most widely used antiarrhythmic agent. Six patients (15%) received an AICD. During the same period 22 patients from the same catchment area received an AICD following an in-hospital cardiac arrest. CONCLUSIONS: Mortality among survivors of non-infarct related prehospital cardiac arrest remains significant, with few patients being referred for specialist investigation. The implementation of recent guidelines on AICD use in cardiac arrest survivors would have resulted in an approximate 60% increase in the total numbers of defibrillators implanted in the West Yorkshire area.

Adult↗
PubMed1999

Comparison of 0.25% S(-)-bupivacaine with 0.25% RS-bupivacaine for epidural analgesia in labour.

We have compared the efficacy of 0.25% S(-)-bupivacaine with 0.25% RS-bupivacaine in providing epidural analgesia for labour in a randomized, multicentre, double-blind study. Analgesia was initiated with 10 ml of the study solution and maintained with 10-ml top-ups. We studied 137 women and treatments were found to be equivalent for onset, duration and quality of block. Median onset of pain relief was 12 min for both drugs and median duration was 49 (range 3-129) min and 51 (7-157) min for S(-)-bupivacaine and RS bupivacaine, respectively. The estimated treatment difference for duration of pain relief was -4 (90% CI -13, 6) min. Thirty patients failed to achieve pain relief after the first injection (20 patients after S(-)-bupivacaine and 10 after RS-bupivacaine; P = 0.039). However, median duration of pain relief from the first top-up was 82 (range 3-164) min for S(-)-bupivacaine and 76 (22-221) min for RS-bupivacaine. There were no significant differences in the quality of analgesia, as assessed by the investigators. There were no significant differences in the extent of sensory block, percentage of patients with motor block or incidence of adverse events.

Adolescent↗
PubMed1998

Extradural S(-)-bupivacaine: comparison with racemic RS-bupivacaine.

Bupivacaine has a chiral centre and is currently available as a racemic mixture of its two enantiomers: R(+)-bupivacaine and S(-)-bupivacaine. Preclinical studies have demonstrated that there is enantiomer selectivity of action with the bulk of central nervous system and cardiovascular toxicity residing with the R(+) isomer. The aim of this study was to compare the clinical efficacy and safety of S(-)-bupivacaine with racemic RS-bupivacaine for extradural anaesthesia. We studied 88 patients undergoing elective lower limb surgery under lumbar extradural anaesthesia who received 15 ml of 0.5% or 0.75% S(-)-bupivacaine, or 0.5% RS-bupivacaine in a randomized, double-blind study. There was no difference in onset time, maximum spread of sensory block or intensity of motor block between the three groups. Duration of sensory block was significantly longer for 0.75% S(-)-bupivacaine. We conclude that S(-)-bupivacaine has similar local anaesthetic characteristics to RS-bupivacaine when used for extradural anaesthesia.

Adult↗
PubMed1998

Comparison of S(-)-bupivacaine with racemic (RS)-bupivacaine in supraclavicular brachial plexus block.

Bupivacaine is used widely as a local anaesthetic but has potential for severe cardiovascular and central nervous system (CNS) toxicity. It has an asymmetric carbon atom giving it a chiral centre, and the commercial preparation is a racemic mixture of its two enantiomers: dextro or R(+)-bupivacaine and levo or S(-)-bupivacaine. Preclinical studies have demonstrated reduced cardiotoxicity and CNS toxicity for S(-)-bupivacaine. In this study we have compared the clinical efficacy of S(-)-bupivacaine with racemic RS-bupivacaine for supraclavicular brachial plexus block in 75 patients undergoing elective hand surgery. Patients received 0.4 ml kg-1 of either 0.25% or 0.5% S(-)-bupivacaine or 0.5% RS-bupivacaine in a randomized, double-blind study. Clinical assessments of sensory and motor block were performed at regular intervals. There were no significant differences in onset time, dermatomal spread or duration of both sensory and motor block between the three groups (the power of the study was 81% to detect a 4-h difference in duration). Duration of sensory block was prolonged with wide interpatient variation: 892 (SD 250) min, 1039 (317) min and 896 (284) min for 0.25% S(-)-bupivacaine, 0.5% S(-)-bupivacaine and 0.5% RS-bupivacaine, respectively. There were no differences in the overall success rate of the technique. We conclude that S(-)-bupivacaine was suitable for local anaesthetic use in brachial plexus block anaesthesia.

Adult↗
PubMed1996

A comparison of epidural infusions of fentanyl or pethidine with bupivacaine in the management of postoperative pain.

A double-blind randomised clinical trial was undertaken in 40 patients undergoing major abdominal surgery. Postoperative pain relief was provided using epidural infusions of 0.06% bupivacaine with fentanyl 4 micrograms.ml-1 (n = 20) (group F) or with pethidine 1.5 mg.ml-1 (n = 20) (group P). Postoperative pain scores using a visual analogue scale (0-100 mm) were not significantly different between the two groups. Median pain scores were 0-19 mm at all times of assessment indicating that good analgesia was provided by both regimens. There was no significant difference between the epidural infusion rates in the two groups. The side effects and effect on pulmonary function were similar in each group. Nine patients were withdrawn from the study (four from group F, five from group P) due to failure of the epidural technique or other complications. Fourteen patients, equally distributed, required a total of 24 epidural 'top-ups' by an anaesthetist because of inadequate analgesia. We demonstrated no advantage with epidural pethidine over fentanyl when used by infusion in combination with bupivacaine in the management of postoperative pain.

Abdomen↗
PubMed1994

Automatic recording and timing of defibrillation on general wards by day and night.

To measure the speed of response to ventricular fibrillation on general medical wards and to assess the importance of this and other factors for survival to leave hospital, 69 consecutive patients with ventricular fibrillation were studied prospectively using an automatic timing device in the hospital telephone exchange and an automatic timer and ECG recording during resuscitation. Twenty-seven patients were initially resuscitated and 17 were discharged from hospital. The median time to connect the monitor after recognition of a cardiac arrest was 127 s (range 0-277) for survivors and 132.5 s (range 0-620) for non-survivors. The median time ventricular fibrillation was displayed before the first shock was 43 s (range 4-75) for survivors and 52 s (range 10-454) for non-survivors. These differences were not significant; but logistic regression analysis identified primary ventricular fibrillation, short display time (logged data), 'early' time of day, absence of pre-existing non-cardiac illness, and post-defibrillation heart-rate > 30 beats.min-1 in rank order as independent predictors of survival. In spite of no significant diurnal variation in response time, successful resuscitations were concentrated in the early nursing shift (0730-1530 h). Four shocks were inappropriate. Clinical diagnosis was more predictive of outcome than the time to the first shock. The reasons for the poorer results in the evening and night are uncertain.

Aged↗
PubMed1994

The effect of oral omeprazole on the disposition of lignocaine.

The effects of the gastric antisecretory drug, omeprazole, on the disposition of lignocaine were studied in 10 healthy male volunteers in a double-blind, randomised, placebo-controlled, two-period crossover trial. Omeprazole 40 mg or placebo was taken daily for one week before administration of lignocaine 1 mg.kg-1 (3.7 mumol.kg-1) given intravenously over 10 min. Venous concentrations of lignocaine and its metabolite monoethylglycinexylidine were measured in plasma with reversed phase liquid chromatography. The mean (95% CI) areas under the curve at infinity for lignocaine after pretreatment with omeprazole or placebo were 6.67 (4.90-8.45) mumol.h.l-1 and 6.14 (5.05-7.23) mumol.h.l-1, respectively (p = 0.44). The respective areas for monoethylglycinexylidine were 1.85 (1.25-2.45) mumol.h.l-1 and 1.79 (1.44-2.14) mumol.h.l-1 (p = 0.78). Similarly, omeprazole had no significant effect on the half-lives of lignocaine or methylglycinexylidine.

Administration, Oral↗
PubMed1991

Comparison of extradural ropivacaine and bupivacaine.

Ropivacaine, a new long acting amide type local anaesthetic, was compared with bupivacaine in a randomized double-blind study. One hundred and ten patients undergoing extradural anaesthesia received a test dose of 3 ml of 1% lignocaine with adrenaline which was followed by 15 ml of one of five solutions: 0.5, 0.75 or 1.0% ropivacaine or 0.5 or 0.75% bupivacaine. There was little difference between the groups with respect to speed of onset or sensory block. The duration of analgesia was increased by increasing the concentration of both drugs, but this had minimal effect on onset time or extent of block. When the same concentration of each drug was administered, there were inconsistent differences in duration of sensory block, none of which was statistically significant. Increasing concentration of both drugs resulted in greater degree and longer duration of motor block. Ropivacaine produced a slower onset, shorter duration and less intense motor block than the same concentration of bupivacaine. The cardiovascular changes were similar in all groups.

Adolescent↗
PubMed1991

Comparison of extradural and intravenous diamorphine as a supplement to extradural bupivacaine.

The influence of route of administration (extradural as compared with intravenous) of diamorphine 0.5 mg/hour as a supplement to extradural bupivacaine (0.125% at 15 ml/hour) was investigated in two groups of 20 patients who underwent major abdominal gynaecological surgery. Significantly more patients in the intravenous group withdrew because of inadequate analgesia (p less than 0.05). Those in the extradural group were significantly more drowsy throughout the study (p less than 0.01), but no major side effects were encountered.

Abdomen↗
PubMed1991

Fetal monitoring with pulse oximetry.

Continuous fetal monitoring was achieved with a fetal scalp pulse oximetry sensor in 86 labours. The average recorded fetal oxygen saturation in early labour (cervical dilatation less than 5 cm) was 68% (SD 13%). At the end of labour (cervical dilatation greater than or equal to 9 cm) the recorded mean oxygen saturation was 58% (SD 17%). The largest range of readings during a single labour was 81%-11% but this drop was associated with cord compression. The average SD during 1 h of normal labour was 10%. A second group of 40 fetuses was monitored during induction of labour before and after elective amniotomy. Oxygen saturation did not appear to change after amniotomy (mean change -0.4%, SD 1.2%) and there was no difference between mean antenatal or early intrapartum readings. We excluded the amniochorionic membranes as a possible source of data corruption by measuring their in vitro absorption spectra and confirming that they do not preferentially absorb light of either 660 or 940 nm wavelength. Non-invasive pulse oximetry can be used to monitor the fetus before and during labour.

Amnion↗
PubMed1991

The accuracy of fetal pulse oximetry in the second stage of labour.

The aim of this study is to assess the accuracy of fetal monitoring with pulse oximetry at delivery. The pulse oximetry reading from the fetus at delivery was compared to fetal condition at birth. There is poor correlation between fetal scalp oximetry readings at delivery and fetal condition (Apgar scores), umbilical venous or arterial blood gas analysis or pH. Although there are good theoretical reasons why the correlation should not be perfect, the wide deviation from expected values suggest that readings taken during delivery are particularly prone to errors. Examination of the unprocessed photodetector signal during the second stage of labour reveals considerable movement interference. The signal may also be affected by congestion and transmitted venous pulsation in the scalp as the head crowns. The current generation of reflectance pulse oximeters can predict fetal hypoxemia during labour but a single reading during delivery is subject to too much movement interference to produce useful data.

Cardiotocography↗
PubMed1990

Resuscitation of patients with cardiac arrest by ambulance staff with extended training in West Yorkshire.

OBJECTIVE: To investigate the results of resuscitation of patients with cardiac arrest by ambulance staff with extended training in West Yorkshire. DESIGN: Study of all such attempts at resuscitation over 32 months, based on the standard report form for each call made by the ambulance staff and the electrocardiogram that showed the initial rhythm in each patient. SETTING: Area covered by West Yorkshire ambulance service. SUBJECTS: 1196 Patients with cardiac arrests attended by 29 ambulance staff with extended training. MAIN OUTCOME MEASURE: Result of resuscitation. RESULTS: The initial rhythm was asystole or electromechanical dissociation in 740 patients and ventricular fibrillation in 456 patients; overall 65 patients survived to be discharged from hospital. Sixty four of the 456 patients in whom ventricular fibrillation was the initial rhythm recorded, and 46 in whom ventricular fibrillation persisted after the ambulance staff arrived, survived. Only one of the 740 patients who initially had asystole or electromechanical dissociation survived. Factors associated with a greater chance of ventricular fibrillation occurring were: age less than 71, the arrest being witnessed by a bystander, resuscitation by a bystander, the arrest occurring in a public place, and a response time by the ambulance staff of less than six minutes. For patients found in ventricular fibrillation a shorter response time was associated with improved survival but resuscitation by a bystander was not. Additional skills learnt during extended training were used for 51 of the 65 patients who survived. CONCLUSIONS: Ambulance staff with extended training can save the lives of patients with cardiac arrest due to fibrillation, though asystole and electromechanical dissociation have a poor prognosis and should perhaps receive little attention during extended training.

Age Factors↗