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Biomedical subjects

B Lyons

Publications and source records attributed to B Lyons.

At least 37 records · Page 2Linked to original sources

Use of protein-C concentrate, heparin, and haemodiafiltration in meningococcus-induced purpura fulminans.

BACKGROUND: Inflammatory and coagulation processes are both affected in meningococcaemia. Severe acquired protein-C deficiency in meningococcaemia is usually associated with substantial mortality: in survivors, skin grafts, amputation, and end-organ failure are not uncommon. Protein C is a natural anticoagulant and also has important anti-inflammatory activity. We assessed the effects of early replacement therapy with protein-C concentrate together with continuous veno-venous haemodiafiltration and conventional treatment in meningococcaemia. METHODS: 12 patients aged between 3 months and 27 years with meningococcaemia and severe acquired protein-C deficiency (mean 0.20 IU/mL) were studied. All patients had septic shock, widespread purpura, skin necrosis, and disseminated intravascular coagulopathy. After a test dose of protein-C concentrate, patients received a continuous infusion with the dose adjusted daily to keep the plasma concentration between 0.8 and 1.2 IU/mL. 11 patients were given unfractionated intravenous heparin (10-15 IU kg-1 h-1). Nine patients had haemodiafiltration and one had peritoneal dialysis. The Glasgow meningococcal septicaemia prognostic score and the paediatric risk of mortality score predicted a minimum mortality of 80% and 57%, respectively. FINDINGS: No patient died. No adverse reactions to the treatment were seen. Two patients had lower-limb amputations, one of whom had a thrombotic cerebrovascular accident; both patients had received the protein-C concentrate and heparin later than the rest of the group (60 h [16.97] vs 12 h [3.13]). One patient developed chronic renal failure despite receiving protein-C infusion 15 h after admission. INTERPRETATION: The acquired severe deficiency of protein C in meningococcaemia contributes to the pathogenesis of the thrombotic necrotic lesions in the skin and other organs and probably has an important role in the inflammatory response. Protein-C therapy is merely one approach to improve the host response in this syndrome. We suggest that a double-blind, randomised, controlled multicentre trial is needed to confirm our results.

Adolescent↗

Unmet long-term care needs of elderly people in the community: a review of the literature.

The extent of unmet need, or the extent to which needed assistance is unavailable for insufficient, is an important issue in public policy and financing of health and support services. This article reviews the research of literature to assess how unmet method is measured, and the extent of unmet needs among elderly people in the community. Measurement difficulties include variable definitions and measures of need across studies, the relative dearth of studies which undertake to measure unmet needs, and varying methodologies used to estimate need and unmet need. In addition, some measures of status and need, such as cognitive impairment and care giver burden are excluded from many estimates. Estimates of unmet need range from around 2 percent to about 35 percent of community dwelling elders, depending on what is included or excluded from the definition. Unmet need is associated with higher disability levels and living alone. The literature suggests that estimates of future unmet need will be mitigated by declining disability levels and increased use of assistive devices among the elder population.

Activities of Daily Living↗

Pain relief with low-dose intravenous clonidine in a child with severe burns.

The case of an 11-year-old boy who suffered second and third degree burns to 78% of his body is reported. The large doses of morphine used as analgesia resulted in severe side effects: ventilatory dependence, impairment of gastrointestinal function and psychological disturbance. Intravenous lignocaine was added without benefit. The addition of low-dose intravenous clonidine, however, precipitated a dramatic reduction in morphine consumption with an attendant improvement in ventilatory, gastrointestinal and psychological functions.

Adrenergic alpha-Agonists↗

The effect of passive smoking on the incidence of airway complications in children undergoing general anaesthesia.

The aim of this study was to assess whether passive smoking affected the frequency of airway complications in children undergoing general anaesthesia. One hundred and twenty-five children undergoing general anaesthesia for elective daycase surgery were monitored for adverse respiratory events and desaturation during induction, intra-operatively and in the recovery room. Oxygen saturation was monitored throughout and a venous sample was taken for estimation of carboxyhaemoglobin levels. Parents were asked to fill in a questionnaire detailing their smoking habits. Sixty-three of the children were passive smokers with a potential daily exposure varying from 5-130 cigarettes. There was no difference in the frequency of respiratory events between passive smokers and those not exposed to cigarette smoke at induction or intra-operatively. However, in the recovery room, desaturation was significantly more common in passive smokers (p < 0.02). This was related to the cumulative number of cigarettes smoked by individuals to whom the child was exposed (p < 0.05). Neither carboxyhaemoglobin levels nor domiciliary address were predictive of desaturation. This study suggests that passive smoking contributes to postoperative arterial oxygen desaturation following general anaesthesia in children.

Ambulatory Surgical Procedures↗

Modification of pain on injection of propofol. A comparison of pethidine and lignocaine.

One hundred and fifty ASA 1 and 2 patients were randomly allocated to receive pethidine 25 mg (1 ml), lignocaine 10 mg (1 ml) or 0.9% saline (1 ml) on a double-blind basis, as pretreatment to reduce pain on injection of propofol. Both active treatments were significantly better than placebo at preventing pain (p < 0.01). Lignocaine was most effective in preventing pain in men (p < 0.05) whilst pethidine was more effective in women (p < 0.05).

Adult↗

Postanaesthetic shivering in children.

This study was designed to assess the incidence, severity and possible aetiological factors of postanaesthetic shivering in children. Three hundred and seventy-six children undergoing general anaesthesia were enrolled in the study. Tympanic membrane temperatures were recorded pre-operatively and every 15 min postoperatively in the recovery room until discharge to the ward. Also recorded were all anaesthetic data including fluid administration, methods of temperature preservation used, sedation scores and shivering (using a four-point scale). The overall incidence of shivering was 14.4%. Multiple regression analysis identified three factors that were significantly related to shivering: age, the administration of atropine and peri-operative temperature changes. Children who shivered rewarmed faster in the recovery room.

Adolescent↗

The anaesthetic management of the child with Eisenmenger's syndrome.

There is little clinical data in the literature on the anaesthetic management of paediatric patients with Eisenmenger's syndrome undergoing non-cardiac surgery. This paper reviews our experiences with either such patients who underwent a total of 11 surgical procedures. Of the eight children, six had Down's syndrome and an atrio-ventricular septal defect, one had a ventricular septal defect and one an atrial septal defect. Nine of the eleven operations consisted of minor dental, plastic or ENT procedures, while one patient underwent two laparotomies. Premedication (trimeprazine/ meperidine combination or midazolam) was administered on three occasions. Induction of anaesthesia was achieved by either inhalation of halothane (2), or intravenously with thiopentone (6), ketamine (2) or propofol (1). Muscle relaxation and mechanical ventilation were employed only for both intra-abdominal procedures, otherwise patients were allowed to breathe spontaneously with, or without, manual assistance. Halothane (8), isoflurane (2) and enflurane (1) were all used for maintenance of anaesthesia. Non-invasive monitoring was applied intraoperatively for minor procedures, and arterial and central venous catheters inserted for the laparotomies. Postoperative analgesia for both these cases was provided by an epidural infusion of bupivacaine 0.125% and fentanyl 5 micrograms x ml(-1). A single im bolus of morphine was required following a dental clearance, otherwise pain relief for the rest of the cases was achieved by local anaesthetic infiltration and NSAIDS. With the exception of a single episode of bradycardia, induction, maintenance and recovery from anaesthesia were well tolerated in all cases. In conclusion, our experience suggests that despite theoretical risks, children with Eisenmenger's syndrome appear to tolerate a variety of anaesthetic techniques.

Anesthesia↗

Premedication for ambulatory surgery in preschool children: a comparison of oral midazolam and rectal thiopentone.

Seventy five ASA 1 and 2 children, aged between six months and five years were randomized to receive oral midazolam 0.5 mg.kg-1, rectal thiopentone 35 mg.kg-1 or no premedication to compare the safety and efficacy of, and parental attitudes to, both premedicants. Cardio-respiratory variables were from the time of premedication to awakening from anaesthesia. In addition, anxiety and sedation scores and patients' acceptance of both premedicant and mask at induction, were all recorded using four-point rating scales. Times to recovery and discharge, and parental satisfaction with the premedication their child had received were also recorded. Children receiving rectal thiopentone had higher sedation scores and were more accepting of the mask than were the other two groups (P < 0.001). Their acceptance of the premedication was similar to that of the midazolam group. Times to spontaneous eye opening and discharge were longer in the thiopentone group (P < 0.005). Parental preoperative satisfaction rating was higher for thiopentone, but not midazolam, than no premedication (P < 0.05). When asked their premedication preferences for subsequent general anaesthetics, a higher proportion of parents whose children were not premedicated requested an alternative regimen (P < 0.01). In conclusion the study found that premedication with rectal thiopentone provided superior induction characteristics to oral midazolam, but with a longer recovery period.

Administration, Oral↗

Intra-articular analgesia for arthroscopic meniscectomy.

Intra-articular morphine has been shown to provide prolonged analgesia after arthroscopic knee surgery; the addition of local anaesthetic agents has been reported to improve this analgesic effect. Pethidine possesses local anaesthetic properties, and therefore this study was designed to evaluate its analgesic efficacy after arthroscopic meniscectomy. Sixty patients were allocated randomly to receive intra-articular injections of pethidine 50 mg, morphine 5 mg or saline after elective arthroscopic meniscectomy. Postoperative pain was assessed using an interval visual analogue scale and measuring analgesic requirements. Both treatment groups had significantly lower pain scores compared with the control group. Patients in the pethidine group had lower pain scores than those in the morphine group at 0.5, 1 and 2 h, but significantly higher scores at 12 and 24 h. These observations suggest that the local anaesthetic effect of pethidine may be responsible for the improved early analgesia, but its duration of action appears to be less than that of morphine.

Adolescent↗

The treatment of postanaesthetic shivering: a double blind comparison between alfentanil and pethidine.

It has been postulated that pethidine may mediate its effects on postanaesthetic shivering (PAS) via kappa-opioid receptors. However, clinical evidence indicates that alfentanil, a pure mu-agonist, may also have beneficial effects on PAS. In order to assess whether opioid effects on PAS are effected via kappa receptors, fifty-one patients were randomised to receive alfentanil 250 micrograms (n = 18), pethidine 25 mg (n = 18) or placebo (n = 15) on a double-blind basis for the treatment of established postanaesthesia shivering (PAS). Both drugs proved significantly better in treating PAS than placebo (P < 0.005). Following treatment, blood pressure fell and oxygen saturation increased in patients in the two treatment groups when compared with the control group (P < 0.05). There was a highly significant incidence of reshivering in the alfentanil treated group (P < 0.005). In conclusion, the high incidence of reshivering indicates that alfentanil is unlikely to supercede pethidine in the treatment of PAS, but its initial success rate implies that pethidine's anti-shivering effect is unlikely to be mediated via kappa-opioid receptors.

Adolescent↗

Automated sequencing of amino acid spin systems in proteins using multidimensional HCC(CO)NH-TOCSY spectroscopy and constraint propagation methods from artificial intelligence.

We have developed an automated approach for determining the sequential order of amino acid spin systems in small proteins. A key step in this procedure is the analysis of multidimensional HCC(CO)NH-TOCSY spectra that provide connections from the aliphatic resonances of residue i to the amide resonances of residue i + 1. These data, combined with information about the amino acid spin systems, provide sufficient constraints to assign most proton and nitrogen resonances of small proteins. Constraint propagation methods progressively narrow the set of possible assignments of amino acid spin systems to sequence-specific positions in the process of NMR data analysis. The constraint satisfaction paradigm provides a framework in which the necessary constraint-based reasoning can be expressed, while an object-oriented representation structures and facilitates the extensive list processing and indexing involved in matching. A prototype expert system, AUTOASSIGN, provides correct and nearly complete resonance assignments with one real and 31 simulated 3D NMR data sets for a 72-amino acid domain, derived from the Protein A of Staphylococcus aureus, and with 31 simulated NMR data sets for the 50-amino acid human type-alpha transforming growth factor.

Amino Acid Sequence↗

'Solitary' necrotic nodules of the liver: an aetiology reaffirmed.

Morphological features of lesions conforming to the description of solitary necrotic nodules of the liver were compared with liver haemangiomata and necrotic tumour metastases in the liver. An origin in haemangiomata is confirmed for most of the lesions studied, although the necrotic nodule may represent the end stage of a variety of lesions. These lesions are usually benign, although necrotic nodules are often mistaken for liver metastases. A reticulin stain is useful in assessing the lesions.

Adult↗