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R Millard

Publications and source records attributed to R Millard.

12 recordsLinked to original sources
PubMed1995

Effect of supplemental perfluorocarbon administration on hypotensive resuscitation of severe uncontrolled hemorrhage.

Recent animal studies of acute hemorrhage in the presence of a vascular injury have demonstrated improved survival and decreased hemorrhage volume with hypotensive resuscitation, but this has occurred at the expense of tissue perfusion. It was hypothesized that addition of an oxygen-carrying perfusate would improve tissue oxygen delivery during hypotensive resuscitation. Hypotensive resuscitation of severe uncontrolled hemorrhage was compared with and without supplementation with Oxygent HT, an emulsion of perflubron (perfluorooctylbromide; PFOB; Alliance Pharmaceutical Corporation, San Diego, CA), an oxygen-carrying perfusate. Fifteen swine (15 to 22 kg) with 4-mm aortic tears were bled to a pulse pressure of 5 mm Hg and then resuscitated (estimated blood loss, 40 to 50 mL/kg). All animals were resuscitated with normal saline (6 mL/kg/min) infused as needed to maintain a mean arterial pressure of 40 mm Hg. One group (PFC) of animals also received an infusion of 6 mL/kg perfluorooctylbromide emulsion. Another group served as controls and received an equal volume of placebo (normal saline). Animals were observed for 120 minutes or until death. Data were compared using repeated measures analysis of variance (ANOVA) the Student's t test, and Fisher's exact. A P value < .05 was considered significant. Two-hour mortality rates were 12.5% and 43% for PFC-treated animals and controls, respectively (P > .05; 95% confidence interval [95% CI] for this difference in mortality is -13% to 74%). Oxygen content and delivery were significantly greater in the treatment group. In conclusion, administration of an oxygen-carrying perfusate significantly improves oxygen delivery in hypotensive crystalloid resuscitation of severe uncontrolled hemorrhage.

Animals↗
PubMed1995

Improved electrotactile speech processor: Tickle Talker.

The Tickle Talker, an eight-channel electrotactile speech processor, has been developed from continuing research at the University of Melbourne. The development of the device has focused on production of reliable speech-processing hardware, design of cosmetically and ergonometrically acceptable electrode transducers, implementation of acute and chronic biomedical studies demonstrating device safety, design and testing of alternative speech-encoding strategies to provide benefit to speech perception and production, and design and testing of appropriate training methods for optimizing benefits. The Tickle Talker has been shown to provide benefits in supplementing lipreading or aided residual hearing for hearing-impaired adults and children. Improvements in speech processing have resulted in an increase in benefits to speech perception, and open the way for more flexible approaches to encoding speech input. Continuing development of the electrode circuitry has now produced a device that is robust and has an extended battery life. Safety studies have clearly demonstrated that there are no long-term contraindications to device use. The results suggest that the device has a role to play in rehabilitation programs for severely and profoundly hearing-impaired adults and children.

Deafness↗
PubMed1994

Perfluorocarbon distribution to liver, lung and spleen of emulsions of perfluorotributylamine (FTBA) in pigs and rats and perfluorooctyl bromide (PFOB) in rats and dogs by 19F NMR spectroscopy.

Perfluorocarbon emulsion (FCE) particles are reported to be taken up by the reticuloendothelial system (RES) and ultimately eliminated by the lung. This distribution provides an opportunity to measure oxygen partial pressure in vivo with fluorine-19 magnetic resonance imaging (19F MRI). Since the MR image signal-to-noise ratio is directly proportional to the fluorine concentration in the tissue, a greater concentration of perfluorocarbon (PFC) in the tissue will result in a greater confidence in the oxygen image and reduce measurement time. It was postulated that the biodistribution of PFC administered in emulsion form may depend on species RES or FCE composition. The distribution of an emulsion (Oxypherol-E.T.) containing perfluorotributylamine (FTBA) 5 days after administration to pigs (11 g FTBA/kg body weight i.p.) and rats (19 g FTBA/kg i.p.) and an emulsion (Oxygent) containing perfluorooctyl bromide (PFOB) 7 days after administration to dogs (11 g PFOB/kg i.v.) and 5 days after administrations to rats (19 g PFOB/kg i.p.) was analyzed by F-19 NMR spectroscopy of tissue samples. PFC concentrations in spleen are 2 to 3 times those in liver. This pattern appears to be independent of PFC emulsion or species. In contrast, lung PFC content was less than that in the liver and showed a dependence upon both species and PFC emulsion.

Animals↗
PubMed1993

Comparative assessment of regional left atrial perfusion by laser Doppler and radionuclide microsphere techniques.

OBJECTIVE: The aim was to study the relation between left atrial microcirculatory flux, using laser Doppler flowmetry (LDF), and blood flow, using radiolabelled microspheres (MS). METHODS: Studies were done in five anaesthetised dogs. LDF probes were sewn to the appendage and body of the left atrium. Radionuclide spheres (15 microns) were used to quantitate blood flow at baseline, and during atrial pacing at 3.5 Hz, atrial fibrillation, and intravenous adenosine infusion (1 mg.kg-1 x min-1). RESULTS: In the left atrial body, both MS and LDF perfusion increased significantly during pacing and adenosine infusion; only LDF registered significant increases during atrial fibrillation. In the left atrial appendage, MS flow failed to increase significantly with any intervention and LDF perfusion increased significantly only during atrial fibrillation. There was a significant but weak correlation (r = 0.36, p < 0.05) between LDF and MS when data from all sample sites (n = 40) were compared, but good correlation when only baseline and pacing data were compared (r = 0.72, p = 0.0004, n = 20). In four additional dogs with heart failure [mean left atrial pressure 25.3(SD 7.4) mm Hg] produced by three weeks of rapid right ventricular pacing, flux values at baseline were increased significantly compared to control dogs and the responses registered by LDF to pacing, atrial fibrillation, and adenosine infusion were attenuated markedly. CONCLUSIONS: (1) Microcirculatory flux detected by LDF can identify the direction, and to a lesser extent, the magnitude of changes in regional atrial perfusion; and (2) LDF may be useful in identifying abnormalities of vasodilator reserve that accompany chronic left atrial myocardial dysfunction.

Animals↗
PubMed1987

Coronary bypass without angiography: an unusual circumstance.

This paper presents an unusual case of an individual with myocardial ischemia, angina pectoris, and myocardial infarction who also had an anaphylactic reaction to angiographic dye. The coronary bypass operation was guided by the use of intraoperative coronary reactive hyperemia assessed by Doppler ultrasound. The patient has had a good response to the operation without additional angina or difficulties.

Angina Pectoris↗
PubMed1977

Treatment of full-thickness abdominal and chest wall losses with split-thickness skin grafting.

A 22-year-old man developed a large abdominal wall and sternal defect resulting from wound dehiscence. This was a sequel to two operations for gunshot wounds of the abdomen, the second one being for intraperitoneal abscess. The infected dehiscence was treated by the open method using povidoneiodine (Betadine) packs. As soon as the patient's condition permitted, split-thickness grafts were applied to the defect. One hundred percent success resulted, and convalescence of this critically ill patient was thereafter uninterrupted until discharge 31 days later. It is the authors' opinion that this method has a wider application than it is usually accredited.

Abdominal Muscles↗