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Biomedical subjects

M D Hayhurst

Publications and source records attributed to M D Hayhurst.

11 recordsLinked to original sources
PubMed1994

Fiberoptic bronchoscopy in the intensive care unit--a prospective study of 147 procedures in 107 patients.

OBJECTIVE: To determine the value and safety of fiberoptic bronchoscopy in an intensive care unit (ICU). DESIGN: Prospective survey. SETTING: ICUs at a tertiary care hospital (except for seven procedures that were performed at a peripheral hospital ICU). PATIENTS: A total of 107 patients with a mean age of 43.9 yrs (range 15 to 84). INTERVENTIONS: One hundred forty-seven fiberoptic bronchoscopy procedures (116 performed on patients who were undergoing mechanical ventilation) were performed on 107 patients. Ninety-four procedures were for diagnostic reasons (upper and lower airway inspection, focal and diffuse pulmonary infiltrates), 37 for therapeutic reasons (bronchial toilet, pulmonary hemorrhage, endotracheal intubation), and 16 for both reasons. Topical anaesthesia was used for fiberoptic bronchoscopy; sedation was rarely needed. Appropriate diagnostic and therapeutic procedures were performed. MEASUREMENTS AND MAIN RESULTS: Oxygen saturation, electrocardiogram, and blood pressure were monitored. Transbronchial biopsies (all on mechanical ventilation) for diffuse pulmonary infiltrates were diagnostic in five of seven cases, and were suggestive of the diagnosis in a further case. Endobronchial biopsies were not diagnostic in any of three cases. Bronchial brushings for microbiology were positive in nine of 50 procedures and for cytology in one of nine procedures. Protected specimen brushes for pulmonary infiltrates gave positive microbiology findings in five of 23 procedures. In pulmonary hemorrhage, focal bleeding was found in five cases, diffuse bleeding in four, and no bleeding source in three. In lobar atelectasis, bronchial toilet led to full reexpansion (n = 20 procedures), partial reexpansion (n = 5), and no change (n = 3). Intubation with fiberoptic bronchoscopy was successful in four of five patients. Hypoxemia (oxygen saturation < 90%) occurred in 29 procedures; it caused no problems. Complications included hemorrhage (n = 2), supraventricular tachycardia (n = 1), pneumothorax (n = 1), pneumatocele (n = 1), and bronchospasm (n = 1). No deaths were attributable to fiberoptic bronchoscopy. CONCLUSIONS: Fiberoptic bronchoscopy in the ICU is safe, contributes valuable diagnostic information, and is useful for therapeutic purposes.

Adolescent↗
PubMed1987

A new low-flow oxygen-conserving cannula.

Evaluation of a low-flow, oxygen-conserving cannula in 20 hypoxaemic patients has shown that the new device produces equivalent saturation at half and quarter the oxygen flow rate of conventional nasal cannulas, resulting in a substantial saving of oxygen.

Evaluation Studies as Topic↗
PubMed1986

A comparison of the effects of almitrine or oxygen breathing on pulmonary arterial pressure and right ventricular ejection fraction in hypoxic chronic bronchitis and emphysema.

Almitrine bismesylate is a new, orally administered, respiratory stimulant that improves arterial blood gas tensions in patients with chronic bronchitis and emphysema, and it may have an effect on the pulmonary circulation and on right ventricular performance. We have, therefore, compared the effects of Almitrine with those of oxygen (given as 3 L/min by nasal prongs) on arterial blood gas tensions, mean pulmonary arterial pressure (Ppa), and right ventricular ejection fraction (RVEF) measured both at rest and during exercise in patients with chronic hypoxemia caused by chronic bronchitis and emphysema. Arterial oxygen tension improved significantly both at rest and during exercise after either 100 mg Almitrine by mouth or when breathing oxygen, both at rest and during exercise. Almitrine increased the mean Ppa at rest from 22 +/- 4 to 35 +/- 5 mmHg (p less than 0.001), and mean Ppa rose further during exercise from 38 +/- 5 mmHg before Almitrine to 49 +/- 7 mmHg (p less than 0.001) after Almitrine. In contrast, oxygen breathing did not change Ppa when at rest but reduced the amount of rise in Ppa during exercise. The change in Ppa after Almitrine correlated with the plasma Almitrine concentration (r = 0.69, p less than 0.05) and was associated with a fall in RVEF at rest from 0.38 +/- 0.03 to 0.32 +/- 0.02 (p less than 0.001). In 5 of the patients who received 50 mg of Almitrine by mouth twice daily for 3 months, the Ppa both at rest and during exercise remained significantly higher than in the control study before receiving Almitrine, but RVEF was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Technical and clinical assessment of oxygen concentrators.

One membrane oxygen enricher (Oxygen Enrichment Company OE-4E) and four molecular sieve (MS) concentrators (Mountain Medical Econo2, De Vilbiss MINI DeVO2, Cryogenic Roomate III, and Mountain Medical Mini O2) have been studied to assess technical and clinical performance. During four weeks of continuous operation at a flow rate of 2 l min-1 (6 l min-1 for OE-4E) consistent oxygen levels were delivered by all machines (mean greater than 93% for MS concentrators, 36.5% for OE-4E). At flow rates of up to 21 mm-1 all four MS machines delivered oxygen concentrations greater than 92%, but at 3 l min-1 (Econo2 89.6%, MINI DeVO2 93.9%, Roomate III 92.0%, Mini O2 85.0%) and at 4 l min-1 (Econo2 78.0%, Mini DeVO2 84.7%, Roomate III 83.3%, Mini O2 69.1%) the two newer machines gave higher oxygen concentrations. In 20 hypoxic patients the mean oxygen saturation levels achieved when they were breathing oxygen from the MS concentrators at a flow rate of 2 l min-1 were similar (Econo2 92.6%, MINI DeVO2 92.5%, Roomate II 92.6%), but the level achieved when they were breathing from the OE-4E, at the equivalent flow rate of 6 l min-1, was lower (91.0%, p less than 0.005). The performance of concentrators in service (Econo2, MINI DeVO2, Mini O2) was satisfactory when judged by patients' oxygen saturation levels and delivered oxygen concentrations. The OE-4E may be indicated for a small number of patients who require oxygen with high humidification. The four MS concentrators studied are all suitable for domiciliary use, but the MINI DeVO2 and Roomate III have advantages in terms of better performance at high flow rates and reduced size and weight.

Aged↗
PubMed1985

Clinical assessment of oxygen conserving devices in chronic bronchitis and emphysema.

We have studied the efficacy of three devices designed to conserve oxygen delivered to patients with hypoxic chronic bronchitis and emphysema. Devices A and B are valve systems, which deliver oxygen only during inspiration. Device C is a modified nasal prongs system incorporating a "moustache reservoir" (Oxymizer, Chad Therapeutics Inc, Woodland Hills, California), which is claimed to produce a higher arterial oxygen saturation (SaO2) from a given flow of oxygen than does continuous delivery through nasal prongs. Devices A and B were found to give the same oxygen saturation as continuous flow oxygen, but only device B reduced the flow of oxygen significantly (p less than 0.01). The flow characteristics of device A were likely to be the cause of this failure to conserve oxygen. Device C produced a higher mean rise in SaO2 than did standard nasal prongs at all oxygen flow rates, and was able to achieve the same rise in SaO2 as standard nasal prongs with a small (25-33%) saving in oxygen delivery. There was, however, considerable variation between patients in the oxygen saving efficiency of device C, with little or no oxygen saving in seven of the 12 patients studied.

Aged↗
PubMed1984

Diagnosis of pulmonary emphysema by computerised tomography.

Eleven patients with peripheral bronchial carcinoma had computerised tomographic (CT) scans before operation. The resected specimens from six of these patients showed mild centri-acinar emphysema. Preoperatively the two groups had not differed significantly in spirometric findings or lung volumes. The frequency distribution curves of EMI numbers within the lung fields of patients who proved to have centri-acinar emphysema differed significantly from those of the group who did not, there being more pixels in the EMI range -450 to -500 in the emphysematous group (p less than 0.001). Detailed assessment of lung density by CT scanning may be useful in the diagnosis of emphysema in life.

Adult↗