Search PubMed⌕ Search

Biomedical subjects

A R Webb

Publications and source records attributed to A R Webb.

51 records · Page 3Linked to original sources
PubMed1990

Local anaesthesia for fibreoptic bronchoscopy: transcricoid injection or the "spray as you go" technique?

Local anaesthesia for fibreoptic bronchoscopy should be given by a safe technique that is not unpleasant to the patient and should provide acceptable conditions for the bronchoscopist. Single injection transcricoid local anaesthesia was compared with the "spray as you go" technique in patients having day case fibreoptic bronchoscopy. Patients were randomised to receive either 100 mg lignocaine by a single cricothyroid puncture or 240 mg lignocaine instilled through the bronchoscope under direct vision. Further doses were given by the operator to both groups as required. The 30 patients receiving transcricoid lignocaine coughed less (3.56 (SD 3.1) coughs/min) than the 32 patients receiving lignocaine through the bronchoscope (5.89 (4.8)/min) despite receiving a lower total dose of lignocaine (322 (25.9) v 451 (20.9) mg). Cricothyroid puncture was not associated with any complications and was not unpleasant for the patients.

Administration, Topical↗
PubMed1990

Attitudes to the delivery of enteral nutritional support to patients in British intensive care units.

OBJECTIVES: To assess the relative roles of medical, nursing and dietetic staff in the nutritional support of critically ill patients and the methods used to calculate energy requirements. DESIGN: Postal questionnaire. SETTING: United Kingdom. PARTICIPANTS: Medical, nursing and dietetic staff of 289 hospitals with three or more intensive care beds. RESULTS: Replies were received from 50.3% of participants. Doctors more commonly claimed responsibility for starting enteral nutrition (81.1%) although nurses and dietitians claimed a share of the decision in 28.6% and 11.4% of replies respectively. Doctors claimed that they alone prescribed enteral nutrition in 52.8% of replies and with dietitians in 17.3% of cases whereas the dietitians claimed that they alone prescribed in 46.6% of replies and with doctors in 22.7%. Estimation was the commonest method used to assess patient energy requirements (68% of doctors, 59.5% of nurses and 51.1% of dietitians). Most respondents believed that this was adequate although not accurate. CONCLUSIONS: There is evident confusion between medical, nursing and dietetic staff over responsibility for enteral nutrition. Without a co-ordinated team approach advances in the enteral nutritional support of critically ill patients are unlikely. Indirect calorimetry, an accurate predictor of an individual patient's energy requirements, has not gained widespread acceptance but will be necessary to tailor nutritional support to individual requirements.

Attitude of Health Personnel↗
PubMed1989

In vitro colloid osmotic pressure of commonly used plasma expanders and substitutes: a study of the diffusibility of colloid molecules.

The rational choice of a plasma substitute for states of hypovolaemia depends partly on its colloid osmotic pressure (COP). We have measured the COP of 108 samples of plasma substitute across selectively permeable membranes which retain molecules greater than 10,000 dalton (COP10) and 50,000 dalton (COP50) the ratio COP50/COP10 providing a potential index of diffusibility of the smaller molecules across capillary membranes. 6% Hespan solution showed a particularly favourable COP50/COP10 ratio at 0.58 indicating a potential for good retention in the circulation whilst 3.5% Haemaccel showed a COP50/COP10 ratio of 0.18 indicating a potential for marked transcapillary diffusion, especially in states of capillary leak. In patients with normal capillary permeability both Gelofusine and Dextran 110 are likely to show adequate retention in the circulation with a COP50/COP10 ratio of 0.37 and 0.39 respectively. These are comparable to the retention of 4.5% human albumin (0.36) but all of the plasma substitutes tested, with the exception of Haemaccel, provided a higher COP across both membranes than 4.5% human albumin solution. An in vivo comparison of these plasma substitutes is required to confirm the advantages of macromolecular colloids in states of capillary leak.

Colloids↗
PubMed1989

Sedation for fibreoptic bronchoscopy: comparison of alfentanil with papaveretum and diazepam.

Sedation for fibreoptic bronchoscopy should produce optimal conditions for the operator, patient comfort and rapid recovery allowing early discharge home. We have compared a regimen producing 'light' sedation with a more traditional regimen producing 'deep' sedation. Seventy-six patients undergoing fibreoptic bronchoscopy under topical anaesthesia were randomized to receive either light sedation with the short acting opiate, alfentanil (median dose 1.1 mg, range 0.5-2.6 mg) or deep sedation with a combination of papaveretum (median dose 10 mg, range 5-15 mg) and diazepam (median dose 8 mg, range 0-20 mg). Both techniques gave equally good operating conditions, although patients given alfentanil coughed less than those given papaveretum and diazepam (U = 2.814 P less than 0.01). Patients recorded their degree of apprehension on a visual analogue scale prior to sedation and the actual degree of comfort experienced after recovery. There was no significant difference between apprehension or comfort between the groups. This was despite a higher degree of amnesia for an irrelevant object shown during the bronchoscopy in the deeply sedated group (chi 2 = 21.084 P less than 0.001). Patients given alfentanil performed significantly better in a modified Romberg test (chi 2 = 4.357 P less than 0.05) and a visualisation test (t = 3.035 P less than 0.01) two hours after the bronchoscopy. Alfentanil produced good operating conditions, patient comfort, less cough and a more rapid recovery, compared to the deep sedation regimen, and is an ideal sedative for fibreoptic bronchoscopy.

Aged↗
PubMed1989

Topical nasal anaesthesia for fibreoptic bronchoscopy: patients' preference for lignocaine gel.

Two techniques for anaesthetising the nose before fibreoptic bronchoscopy have been compared. Fourteen of 16 patients given lignocaine spray found it unpleasant, compared with three of 20 patients given lignocaine gel. The two forms of local anaesthetic were found to be equally effective. Lignocaine gel is therefore recommended for topical nasal anaesthesia before fibreoptic bronchoscopy.

Anesthesia, Local↗
PubMed1989

Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation.

Exposure to sunlight initiates the formation of vitamin D3 in skin as the UV B radiation in the solar spectrum causes the photoconversion of 7-dehydrocholesterol to previtamin D3. A heat-induced isomerization then converts previtamin D3 to vitamin D3 over a period of days. A number of irradiation products of vitamin D3 are known to form upon irradiation with high intensity UV radiation, but the effect of subsequent exposures to sunlight on the vitamin D3 formed in skin is not known. To investigate this phenomenon, human skin containing vitamin D3 was exposed to sunlight in Boston. A model system of [3H]vitamin D3 in methanol was also used to study the effects of sunlight on vitamin D3 throughout the year. Vitamin D3 proved to be exquisitely sensitive to sunlight, and once formed in the skin, exposure to sunlight resulted in its rapid photodegradation to a variety of photoproducts, including 5,6-transvitamin D3, suprasterol I, and suprasterol II.

Boston↗
PubMed1988

Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin.

Sunlight has long been recognized as a major provider of vitamin D for humans; radiation in the UVB (290-315 nm) portion of the solar spectrum photolyzes 7-dehydrocholesterol in the skin to previtamin D3, which, in turn, is converted by a thermal process to vitamin D3. Latitude and season affect both the quantity and quality of solar radiation reaching the earth's surface, especially in the UVB region of the spectrum, but little is known about how these influence the ability of sunlight to synthesize vitamin D3 in skin. A model has been developed to evaluate the effect of seasonal and latitudinal changes on the potential of sunlight to initiate cutaneous production of vitamin D3. Human skin or [3 alpha-3H]7-dehydrocholesterol exposed to sunlight on cloudless days in Boston (42.2 degrees N) from November through February produced no previtamin D3. In Edmonton (52 degrees N) this ineffective winter period extended from October through March. Further south (34 degrees N and 18 degrees N), sunlight effectively photoconverted 7-dehydrocholesterol to previtamin D3 in the middle of winter. These results quantify the dramatic influence of changes in solar UVB radiation on cutaneous vitamin D3 synthesis and indicate the latitudinal increase in the length of the "vitamin D winter" during which dietary supplementation of the vitamin may be advisable.

Alberta↗
PubMed1987

The behavioural response to the 5-hydroxytryptamine1B (5HT1B) receptor agonist--RU-24969 may exhibit a circadian variation in the mouse.

The effects of the 5-hydroxytryptamine1B receptor agonist RU-24969 on locomotor activity were examined at different times during the light-dark cycle in the mouse. A dose-dependent hyperlocomotion was observed following RU-24969 administration which was partially antagonised by the non-selective 5-hydroxytryptamine receptor antagonist metergoline. The dose ratios for RU-24969 at two different times tested (8 hr after lights-on, L8; 5 hr after lights-off, D5) were significantly different in the presence of metergoline (2 and 5 mg/kg i.p.). The data suggest that the receptor(s) involved in the behavioural response to RU-24969 in the mouse exhibit a circadian variation.

Animals↗
PubMed1983

Infantile hypertrophic pyloric stenosis in South Glamorgan 1970-9. Effects of changes in feeding practice.

In a retrospective analysis of cases of surgically confirmed infantile hypertrophic pyloric stenosis (IHPS) in South Glamorgan in the decade 1970-9 the incidence rose sharply in 1976 reflecting a general increase reported throughout Wales and from other parts of the United Kingdom. The increase was mainly among boys and although it occurred at a time when breast feeding had become more popular, it affected bottle fed infants more than breast fed infants. The apparent correlation between incidence of IHPS and incidence of breast feeding may coincidental and changes in infant milk formulae that became general in 1976 may be more important. An appreciable excess of first born infants with IHPS was noted but there was no correlation between birthweight and IHPS. Variations according to month of birth did not coincide with true seasonal variation.

Birth Order↗
PubMedDate not supplied

Hand grip dynamometry as a predictor of postoperative complications reappraisal using age standardized grip strengths.

A mechanical hand grip dynamometer was used to derive age- and sex-related standard grip strengths from 247 healthy volunteers between 16 and 95 yr old. Preoperative grip strength was measured in 90 patients and related to postoperative complication rates. A grip strength of 85% standard for age and sex was found to be the most effective cut-off for prediction of postoperative complications in terms of sensitivity and specificity, predicting 74% of the complications (p less than 0.05). Specificity is improved over previously published standards related to sex alone especially when assessing the elderly patient (50% vs 21%). A grip strength below the recommended cut-off for age and sex suggests that the patient is in a high-risk group and demands further investigation of nutritional status. Studies of pre-operative nutritional support for the at risk group need to be undertaken.

Adolescent↗