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Biomedical subjects

J H Antrobus

Publications and source records attributed to J H Antrobus.

7 recordsLinked to original sources
PubMed1991

An open study to compare the pharmacokinetics, safety and tolerability of a multiple-dose regimen of azithromycin in young and elderly volunteers.

An open, parallel study was conducted to compare the pharmacokinetics of oral azithromycin in young and elderly healthy volunteers. A total of 12 young subjects (six males, six females) with a mean age of 29 (range 22-39) years and another 12 elderly subjects (six males, six females) with a mean age of 72 (range 67-80) years were given a standard five-day therapeutic regimen of azithromycin (500 mg single dose on day 1 and 250 mg once daily on days 2-5). Pharmacokinetic results indicated that Cmax, Cmin and urinary excretion were similar in the two age groups. Mean AUC0-24 was significantly greater (2.7 micrograms.h/ml) at day 5 in the elderly subjects compared with the younger age group (AUC0-24 = 2.1 micrograms.h/ml) (p = 0.041). Similarly, tmax values on days 1 and 5 were significantly greater in the elderly subjects; 3.8 h compared with 2.5 h in young subjects (p = 0.005) on day 1 and 4.4 h, compared with 3.2 h (p = 0.047) on day 5. There was also evidence of an inverse relationship between creatinine clearance and AUC0-24 (p less than 0.01) but not urinary excretion or Cmax. Despite these observations, it is concluded that the differences between the two age groups were of insufficient magnitude to warrant a dose modification in elderly subjects with only mild renal impairment. Side effects, chiefly headache and gastrointestinal symptoms, were reported by seven subjects in each group. No subject, however, was withdrawn from the study and there were no treatment-related abnormalities in any of the laboratory parameters measured.

Administration, Oral↗
PubMed1991

Pattern of breathing during upper gastrointestinal endoscopy: implications for administration of supplemental oxygen.

Cardiopulmonary complications account for half the deaths associated with upper gastrointestinal endoscopy. The incidence of hypoxia at the time of upper gastrointestinal endoscopy can be greatly reduced by the administration of supplemental oxygen via nasal cannulae. Using dual thermistors in the mouth and nostrils of patients undergoing upper gastrointestinal endoscopy, the present study demonstrates that most patients breathe predominantly via the oral, rather than the nasal, route following intubation of the oesophagus. The implication from the study is that, if supplemental oxygen is to be used in 'at risk' patients, it would be logical to employ an oral, rather than nasal, route of administration.

Endoscopy, Gastrointestinal↗
PubMed1990

Bolus or slow titrated injection of midazolam prior to upper gastrointestinal endoscopy? Relative effect on oxygen saturation and prophylactic value of supplemental oxygen.

A total of 131 patients undergoing upper gastrointestinal endoscopy were sedated with midazolam given as a bolus injection over 5 seconds. The oxygen saturation was continuously measured using a pulse oximeter. Supplemental oxygen was given via nasal cannulae at a rate of 3 litres per minute to 54 patients, while the remaining 77 patients only received oxygen if their oxygen saturation dropped below 85%. Both groups in the present series were compared with 3 previously published series of patients, in whom we had used intravenous midazolam as a slow titrated injection. Despite using on average only two-thirds of the dose of midazolam, following bolus injection the degree of oxygen desaturation during the endoscopic procedure was greater, and the ability of supplemental oxygen delivered via nasal cannulae to prevent hypoxia was less (P less than 0.01), than with a slow titrated injection.

Adult↗
PubMed1988

Anxiety and informed consent. Does anxiety influence consent for inclusion in a study of anxiolytic premedication?

Forty-three consecutive patients were interviewed on the eve of elective gynaecological surgery to determine the effect of anxiety on the granting of informed consent to participate in an hypothetical study. Anxiety was assessed using the Spielberger state-trait anxiety inventory and 10-cm linear analogue scale. A standardised explanation of an hypothetical premedication study was given and the patients' consent requested. Results were grouped for those who granted (n = 33) and those who withheld (n = 10) consent: anxiety scores for the latter were significantly higher (p less than 0.01). It is concluded that patients with high pre-operative anxiety levels are more likely to withhold consent for inclusion in premedication studies than are those who are less anxious. Seeking informed consent would introduce bias into studies of anxiolytic premedication.

Adult↗
PubMedDate not supplied

Upper gastrointestinal endoscopy: a prospective randomized study comparing continuous supplemental oxygen via the nasal or oral route.

We have examined the efficacy of supplemental oxygen in preventing episodes of significant arterial desaturation (SpO2 less than 90%) during upper gastrointestinal endoscopy. We have compared the effects of 2 liters.min-1 of oxygen given orally via the bite-guard with the same flow rate via nasal cannulas and have also examined the effects of pre-oxygenation. Results of this study at a flow rate of 2 liters.min-1 have been compared with previously published results at a flow rate of 3 liters.min-1. Although in this study fewer episodes of desaturation were seen in the orally supplemented group compared with the nasal group, the difference observed was not statistically significant. Pre-oxygenation significantly reduced episodes of desaturation (SpO2 less than 90%, p less than 0.01) and prevented SpO2 falls below 85% in all patients studied. Supplemental oxygen given at a rate of 2 liters.min-1 was as effective as that given at a rate of 3 liters.min-1 in preventing significant desaturation, as previously defined, during the procedure. We therefore recommend the use of supplemental oxygen at a flow rate of 2 liters.min-1 in all high risk patients and conclude that the oral route has practical advantages and is at least as effective as nasal cannulas.

Endoscopy, Gastrointestinal↗