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Biomedical subjects

J W Bradley

Publications and source records attributed to J W Bradley.

At least 19 recordsLinked to original sources
PubMed2002

Two administration methods for inhaled salbutamol in intubated patients.

AIMS: To compare serum concentrations and effects on respiratory mechanics and haemodynamics of salbutamol administered by small volume nebuliser (SVN) and metered dose inhaler (MDI) plus spacer. METHODS: Blinded, randomised, crossover study in 12 intubated infants and children (mean age 17.8 months) receiving inhaled salbutamol therapy. Subjects received salbutamol as 0.15 mg/kg by SVN and four puffs (400 microg) by MDI plus spacer at a four hour interval in random order. Passive respiratory mechanics were measured by a single breath/single occlusion technique, and serum salbutamol concentrations by liquid chromatography-mass spectrometry at 30 minutes, 1, 2, and 4 hours after each dose. Haemodynamics (heart rate and blood pressure) were recorded at each measurement time. RESULTS: There was no difference in percentage change in respiratory mechanics or haemodynamics between the two methods of administration. Mean area under the curve (AUC(0-4)) was 5.86 for MDI plus spacer versus 4.93 ng/ml x h for SVN. CONCLUSIONS: Serum concentrations and effects on respiratory mechanics and haemodynamics of salbutamol were comparable with the two administration methods under the conditions studied. Future studies are needed to determine the most effective and safe combination of dose and administration method of inhaled salbutamol in mechanically ventilated infants and children.

Albuterol↗
PubMed2001

The role of anesthesiologists in Canadian undergraduate medical education.

PURPOSE: To examine the current role of anesthesiologists in Canadian undergraduate medical education (UME). METHODS: A 93-item questionnaire was mailed to the undergraduate course chairs/coordinators for anesthesia at the 16 medical schools in Canada. RESULTS: Of the faculty anesthesiologists in Canada, 1.7%, 4.9%, and 4.9% teach pre-clerkship lectures, seminars, and PBL tutorials, respectively. Annually, anesthesiologists teach an average of 3.3 hr (range: 0 to 15) of pre-clerkship lectures and 12.8 hr (range: 0 to 48) of pre-clerkship seminars at each medical school. The topics most commonly taught by anesthesiologists in pre-clerkship lectures and seminars are pharmacology and perioperative patient assessment, respectively. An anesthesia rotation during clerkship is mandatory at 13 schools, with an average duration of 9.6 dy (range: 5-20 dy). Clerkship teaching methods vary: ten schools provide seminars, eight use videos, six use computers, six use an airway skills laboratory, and four use an anesthesia simulator. The most common topics taught in clerkship anesthesia seminars are airway management and fluid therapy. CONCLUSION: A very small proportion of faculty anesthesiologists participate in Canadian UME at the pre-clerkship level. Considerable variation exists in the amount and format of teaching by anesthesiologists among the Canadian undergraduate curricula, particularly at the pre-clerkship level. However, our results indicate that anesthesiologists are assuming a more important teaching role during clerkship. Our findings may suggest that Canadian medical schools are overlooking the advantages that anesthesiologists offer to UME at the pre-clerkship level, or that many anesthesiologists are reluctant to assume pre-clerkship teaching responsibilities.

Anesthesiology↗
PubMed2000

Albuterol delivery by metered-dose inhaler in a pediatric high-frequency oscillatory ventilation model.

OBJECTIVES: To assess albuterol delivery by metered-dose inhaler (MDI) in a pediatric lung model ventilated by high-frequency oscillatory ventilation (HFOV). The percentage albuterol dose lost in the circuit's expiratory limb and the effects of operating frequency, inspiratory time, and use of a spacer were also determined. DESIGN: Prospective in vitro laboratory study. SETTING: Research laboratory. INTERVENTIONS: A model consisting of a HFOV and circuit, 4.5-mm endotracheal tube, and lung simulator was assembled. Ventilator settings were the following: humidified FIO2 of 1.0; mean airway pressure of 28 cm H2O; operating frequency of 10 Hz; pressure amplitude of 55 cm H2O; bias gas flow to maintain mean airway pressure; 30% inspiratory time; and temperature of 35 degrees C (95 degrees F). Lung simulator compliance and resistance values were consistent with pediatric patients with pulmonary disease. A total of ten MDI canisters were used to administer 2000 microg of albuterol with a spacer. Circuit filters placed proximal to the lung simulator and in the circuit's expiratory limb collected albuterol exiting the endotracheal tube and any albuterol lost, respectively. Filters were rinsed with water and albuterol concentrations determined by high performance liquid chromatography. Albuterol administration was repeated at operating frequencies of 5 and 15 Hz, inspiratory times of 40% and 50%, and with an actuator instead of a spacer. Each test condition was repeated ten times. Analysis of variance or Student's t-test was used to determine significant differences in albuterol delivered or lost among the operating frequencies and inspiratory times, and between the spacer and actuator. MEASUREMENTS AND MAIN RESULTS: Albuterol delivery to the lung simulator was <1% of the administered dose regardless of the operating frequency, inspiratory time, or use of a spacer or actuator. Albuterol lost in the expiratory limb ranged from 3.28% to 14.89% of the administered dose. CONCLUSIONS: These in vitro results suggest albuterol delivery by MDI in a pediatric model of HFOV is negligible, regardless of the operating frequency, inspiratory time, or use of a spacer or actuator.

Albuterol↗
PubMed1996

Albuterol delivery by metered-dose inhaler in a mechanically ventilated pediatric lung model.

OBJECTIVES: To assess albuterol delivery by metered-dose inhaler in a mechanically ventilated pediatric lung model and to determine the influence of the following variables on albuterol delivery: endotracheal tube diameter; type of spacer; humidification; and pulmonary mechanics. DESIGN: Prospective, in vitro, laboratory study. SETTING: Research laboratory. INTERVENTIONS: A model, consisting of a volume-cycled ventilator, pediatric breathing circuit, 4.0- or 6.0-mm endotracheal tube, and lung simulator, was assembled. Ventilator settings were: tidal volume 250 mL; FIO2 0.5; inspiration/expiration ratio 1:3; respiratory rate 25 breaths/min; positive end-expiratory pressure 3 cm H2O; temperature 35 degrees C; and a decelerating flow pattern, using dry and humidified air. Lung simulator compliance and resistance values were consistent with those values reported for healthy childeren (20 mL/cm H2O and 40 cm H20/L/sec) and children with pulmonary disease (10 mL/cm H2O and 60 cm H2O/L/sec). Pulmonary mechanics were verified with a pulmonary function diagnostic system. Ten metered-dose inhaler canisters were used to administer 2000 micrograms of albuterol, using either a collapsible or a rigid spacer. A circuit filter placed immediately proximal to the test lung collected drug exiting the endotracheal tube. The filter was rinsed with water and albuterol concentrations were determined by high-performance liquid chromatography. Each variable was tested in triplicate. MEASUREMENTS AND MAIN RESULTS: Albuterol delivery was significantly (p < or = .05) greater for the 6.0-mm endotracheal tube, rigid spacer, dry air, and pulmonary disease mechanics by multifactor analysis of variance. Drug delivery in humidified air with pulmonary disease mechanics using the rigid chamber was 2.5 =/- 0.27% and 6.3 =/- 0.99% for the 4.0- and 6.0-mm endotracheal tubes, respectively. CONCLUSIONS: These in vitro results suggest that pulmonary disease mechanics and a 6.0-mm endotracheal tube improve albuterol delivery. Future clinical investigations in intubated pediatric patients with pulmonary disease are needed to address the clinical significance of these results.

Albuterol↗
PubMed1994

Prevention of phantom pain after major lower limb amputation by epidural infusion of diamorphine, clonidine and bupivacaine.

Phantom limb pain may appear in up to 85% of patients after amputation. There is no effective treatment. Perioperative epidural infusion of morphine and bupivacaine, alone or in combination, is effective in preventing phantom limb pain in patients with pre-existing limb pain. Serious side-effects, however, make them difficult to manage on a general ward. Clonidine has been shown to be an effective postoperative analgesia when applied epidurally. To mitigate the potentially serious side-effects of all these drugs, we have studied their combined efficiency in preventing phantom limb pain in a prospective controlled study of 24 patients undergoing lower limb amputation. In the study group (n = 13), an epidural infusion containing bupivacaine 75 mg, clonidine 150 micrograms and diamorphine 5 mg in 60 ml normal saline was given at 1-4 ml/h 24-48 h preoperatively and maintained for at least 3 days postoperatively. The control group (n = 11) received on-demand opioid analgesia. Pain was assessed by visual analogue scale at 7 days, 6 months and 1 year. At 1 year follow-up, one patient in the study group and eight patients in the control group had phantom pain (P < 0.002) and two patients in the study group versus eight patients in the control group had phantom limb sensation (P < 0.05). There was no significant improvement in stump pain. We conclude that perioperative epidural infusion of diamorphine, clonidine and bupivacaine is safe and effective in reducing the incidence of phantom pain after amputation.

Adult↗
PubMed1993

Infantile hypertrophic pyloric stenosis: where should it be treated?

A retrospective analysis in the form of an audit into the management of infantile hypertrophic pyloric stenosis in a district general hospital has revealed that the results are equivalent to that of published data from specialised units. It is stressed in this study that close co-operation has to be maintained between paediatricians and surgeons in the care of these infants. The diagnosis can be made on clinical grounds in the majority of cases. The operation has to be carried out by experienced surgeons and anaesthetists. The morbidity can be minimised under these circumstances and pyloromyotomy can be performed safely in a district general hospital.

Female↗
PubMed1992

Naproxen-associated vasculitis.

Three cases of digital vasculitis attributable to naproxen ingestion are reported. The vasculitic changes were reversed by withdrawal of the drug. These three cases emphasize the need to consider drug sensitivity as a cause of unexplained digital vascular lesions.

Acute Disease↗
PubMed1988

Lymphocytes of the intestinal mucosa of chickens.

Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.

Animals↗