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Biomedical subjects

J Bannister

Publications and source records attributed to J Bannister.

36 records · Page 2Linked to original sources
PubMed1990

An open study of ropivacaine in extradural anaesthesia.

Ropivacaine 0.5%, 0.75% and 1.0% was investigated in an open study of extradural anaesthesia in three groups of 15 patients undergoing urological or orthopaedic surgery. Following a test dose of 3 ml of 1.0% lignocaine with 1:200,000 adrenaline, ropivacaine 20 ml was given in incremental doses over 4 min via a lumbar extradural catheter. The onset time for analgesia was short in all groups: T12 was blocked 4-6 min after the end of the injection of ropivacaine. The maximum segmental level was significantly higher in the 0.75% and the 1.0% groups (T2) than in the 0.5% group (T5). Complete motor block was obtained in seven, four and nine patients in the 0.5%, 0.75% and the 1.0% groups, respectively. Duration of analgesia increased with increasing concentration of ropivacaine: mean duration of analgesia was 203 and 266 min at T10 and 253 and 314 min at L5 for the 0.5 and 1% solutions, respectively. Mean duration of complete motor block was 94 and 192 min for the same solutions. Analgesia was satisfactory for surgery in all patients except for one in the 0.75% group. Hypotension was experienced by three, seven and three patients in the 0.5%, 0.75% and 1.0% groups, respectively. Bradycardia occurred in seven patients and was associated with hypotension in five. Backache was experienced after operation by four patients, and three patients complained of a brief mild headache. No late adverse events were seen.

Amides↗
PubMed1990

Effect of glucose concentration on the intrathecal spread of 0.5% bupivacaine.

We have studied the effects of intrathecal injection of 0.5% bupivacaine in solutions containing different concentrations of glucose (0.33%, 0.83% and 8%) in three groups of 10 patients. The mean maximum extent of sensory block was significantly higher with 8% glucose (T3.6) than with 0.83% glucose (T7.2) or 0.33% glucose (T9.5). Administration of solutions containing 0.33% glucose produced a greater variability in upper level of sensory block (11 dermatomes) than the two other concentrations (six dermatomes each). The rate of onset of sensory block to T12 was fastest with solutions containing 8% glucose. Complete motor block of the legs was produced in every patient.

Adult↗
PubMed1990

The effect of caput succedaneum on oxygen saturation measurements.

Advances in oximetry have allowed the obstetrician to measure oxygen saturation in the fetus with non-invasive transcutaneous techniques. The influence of caput succedaneum formation on the oxygen saturation results obtained with a pulse oximeter was studied in 30 newborn infants. Caput was associated with a reduced oxygen saturation reading (mean reduction of 15%; P less than 0.001). This effect is partly due to a true drop in local tissue oxygenation but is exacerbated by a systematic error intrinsic to the physics of spectrophotometry. If continuous intrapartum oximetry is ever to become a part of routine obstetric monitoring then probes that pass through the cervix beyond the caput of the presenting part will be required if erroneously low readings are to be avoided.

Edema↗
PubMed1990

The effect of meconium on neonatal and fetal reflectance pulse oximetry.

Reflectance probes are being developed for neonatal use and obstetricians are beginning to use reflectance pulse oximetry to monitor the fetus. When a reflectance probe was used to monitor the arterial oxygen saturation of a baby whose skin was stained with meconium an artificially low result was obtained. This is because meconium absorbs more red than infra-red light and acts as a red light filter between the vascular bed and the probe. This effect may be reproduced by interposing a red filter between a reflectance pulse oximetry probe and the skin. Obstetricians who use a pulse oximeter to assess the fetus through intact membranes will record an erroneously low result if they are stained with meconium. Similarly neonatologists should avoid placing a reflectance pulse oximetry probe on babies skin which is stained with meconium.

False Negative Reactions↗
PubMed1989

A simple method for increasing hapten immunogenicity by a specific structural modification of the carrier.

A simple procedure to bind haptens, drugs or peptides selectively through their amino or carboxylic group to a spacer arm modified non-immunogenic polypeptide is described. Gelatin, a well known non-immunogenic carrier, was modified by blocking its amino groups. Spacer arms with primary amino groups such as beta-alanine or ethylenediamine were conjugated to this protein by carbodiimide resulting in spacer modified gelatin. These modified polypeptides were tested for their ability to selectively bind haptens through their amino or carboxylic groups. Three probes were used and the results obtained confirm the hypothesis. Three conjugates obtained were further used to induce an immune response in mice. Enhancement of the immunogenicity of these spacer-arm supported haptens was observed. Overall, this study provides a rational approach to the production of well defined antigens using a simple conjugation technique.

Acetylation↗
PubMed1975

Slipped femoral capital epiphysis: a review of 49 cases treated at the University of New South Wales teaching Hospitals over the last ten years.

The purpose of this paper is to assess critically the results of treatment of slipped femoral capital epiphyses in patients seen over the past ten years at the Prince of Wales Hospital. The problems examined in this study include: (a) the indications for prophylactic pinning; (b) the number of Knowles pins necessary for fixation; and (c) the questions whether and when these should be removed.

Adolescent↗
PubMedDate not supplied

Comparison of two methods of transporting paramedics to cardiac arrests outside hospital.

OBJECTIVE: To compare the deployment of paramedics in a separate rapid response unit with their deployment in a standard emergency ambulance. DESIGN: A one year period of each deployment. SETTING: Throughout the community in some parts of West Yorkshire. PARTICIPANTS: All patients receiving resuscitation for cardiac arrest by paramedics. INTERVENTIONS: Using the same group of paramedics and central control, 12 months with the paramedics deployed in separate cars in addition to the standard ambulances (period 1) were followed by another 12 months when they were deployed as one crew member of a standard emergency ambulance (period 2). MAIN OUTCOME MEASURES: Number of arrests attended, number of patients in ventricular fibrillation at paramedic arrival, response times, survival to leave hospital. RESULTS: In period 1, 580 arrests were attended with 31 survivors. In period 2, 462 arrests resulted in 25 survivors. The mean response time was shorter in period 1 (6.24 versus 6.60 min, Cl--0.01-0.73 min). In period 1, 217 patients were found in ventricular fibrillation (23 survivors): In period 2, 141 patients were found in ventricular fibrillation (11 survivors). CONCLUSION: Separating paramedics from the standard emergency ambulances increases the number of survivors of cardiac arrest but the difference may not be sufficiently large to justify the additional expenditure.

Ambulances↗
PubMedDate not supplied

Spinal anesthesia with 0.5% S(-)-bupivacaine for elective lower limb surgery.

BACKGROUND AND OBJECTIVES: This study examines the clinical effects of the subarachnoid administration of levobupivacaine, the S(-)-enantiomer of racemic bupivacaine. METHODS: An open, noncomparative study was performed on 20 patients undergoing elective lower limb surgery. Three milliliters of a plain solution of 0.5% S(-)-bupivacaine ( 15 mg) was administered via the L2 or L3 interspace with the patient in the sitting position. Following injection, the patients were immediately placed supine. Spread of sensory analgesia, degree of motor block, and hemodynamic parameters were recorded. RESULTS: Satisfactory surgical anesthesia was achieved in 18 patients. The median time to onset of analgesia was 2 minutes (ranging 2-10 minutes) and the median duration of analgesia was 388 minutes (range, 295-478 minutes). This group of patients achieved complete motor block, with a median onset time of 5 minutes (2-10 minutes) and duration of 266 minutes (range, 170-415 minutes). Sensory block height was inadequate for surgery in 2 patients, who received supplemental anesthesia. CONCLUSIONS: The results suggest that S(-)-bupivacaine can provide satisfactory surgical anesthesia, but the spread of the plain solution is unpredictable.

Adult↗
PubMedDate not supplied

Skin blood flow changes in response to intradermal injection of bupivacaine and levobupivacaine, assessed by laser Doppler imaging.

BACKGROUND AND OBJECTIVES: The vascular effects of local anesthetics are important determinants of their therapeutic activity. Drugs that vasoconstrict have the potential clinical advantages of limited systemic uptake and prolonged duration of effect. The aim of this study was to assess quantitatively the cutaneous vasoactivity of racemic bupivacaine and one of its enantiomers, levobupivacaine. METHODS: Four concentrations of each drug (0.1 mL each of 0.125%, 0.25%, 0.5%, and 0.75%), as well as normal saline, were injected intradermally into randomly assigned sites on the forearms of 10 volunteers. We measured skin blood perfusion using laser Doppler imaging before injection and at 2.5, 10, 20, 40, 60, and 90 minutes thereafter. RESULTS: Both drugs produced a rapid, dose-dependent increase in skin perfusion (P <.001). Saline also caused an increase in perfusion, although less sustained. By 40 minutes, most responses had returned to baseline levels. However, after this time, perfusion continued to decrease, below baseline, for both bupivacaine and levobupivacaine. The exception to this was 0.75% bupivacaine, the response to which was significantly higher than the same concentration of levobupivacaine over this later period (P <.05). CONCLUSIONS: Bupivacaine and levobupivacaine both have a biphasic effect on skin microvessels. The vasoconstriction observed after 40 minutes may occur when the quantity of drug remaining at the administration site has decreased to a lower level. The continued vasodilatation caused by bupivacaine is more difficult to interpret. The results suggest that these local anesthetics cause vasodilatation at high doses and vasoconstriction at lower, subclinical doses. This hypothesis and the clinical relevance of these effects warrant further investigation.

Administration, Cutaneous↗
PubMedDate not supplied

Hemostasis-altering drugs and central neural block. A survey of anesthetic practice in Scotland and the United Kingdom.

BACKGROUND AND OBJECTIVES: There is debate regarding the use of central neural block in the presence of hemostasis-altering drugs. This study aims to examine current practice. METHODS: A survey was made of the members of the Scottish Society of Anaesthetists and the U.K. branch of the European Society of Regional Anaesthesia to determine the pattern of use of central neural block in patients who are receiving drugs known to alter hemostasis. RESULTS: Spinal anesthetics were considered safer than single epidural injections (P < .05) and single epidural injections safer than infusions via epidural catheters (P < .05). CONCLUSIONS: There is general agreement regarding contraindication of central neural block in the presence of full anticoagulation with either heparin or warfarin, but there is less consensus about the use of central neural block in the presence of low-dose subcutaneous heparin. There is some confusion about the role of aspirin and its duration of action.

Anesthesia, Epidural↗
PubMedDate not supplied

Management and health status in the first year after out-of-hospital cardiac arrest.

The one-year survival, functional and cerebral capacity and patient management following out-of-hospital cardiac arrest were examined in a follow-up study of 143 prospectively identified patients discharged from a West Yorkshire hospital between January 1987 and July 1993. One-year survival was 87%; 13 of the 18 deaths were cardiac related; 89% of survivors had no further cardiac related admissions; 98% of patients surviving to one year were capable of independent daily activities. There was low utilisation of simple drug therapy: 23% of patients were discharged taking beta-blockers and 52% aspirin; 50% of patients discharged after a primary arrhythmic event were taking antiarrhythmic therapy or were given an implantable defibrillator. Irrespective of the availability of invasive cardiac facilities, there was underutilisation of investigations: only 39% of patients were seen by a cardiologist and 54% were not evaluated for ischaemic risk. Significant improvements in patient management could probably be achieved quickly without substantial increases in resources.

Adolescent↗