Are chest pain observation units essential for rapid and effective emergency care in the UK?
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Biomarkers↗
Biomedical subjects
F Dunn
Publications and source records attributed to F Dunn.
Plastic baton round injuries.
OBJECTIVES: To review the injuries resulting from a new plastic baton round. METHODS: Review of case notes of patients presenting with injuries caused by plastic baton rounds over a four month period in Northern Ireland. RESULTS: Twenty nine patients were identified, 28 with 30 injuries were included in the study. Eighty nine per cent were male; the average age was 24.3 years. Seven patients required admission. There were no fatalities. Five injuries were to the upper limbs and 16 to the lower limbs. Three patients sustained pulmonary contusions. There were no head injuries. CONCLUSIONS: Although the numbers in this study are small it should be noted that no patient suffered a face, neck, or head injury. This is in contrast with previous studies in which up to 41.4% of attendances were for face, neck, or head injuries. In this study there were seven injuries to the trunk. Of the 14 deaths attributable to plastic baton rounds in Northern Ireland, all have been the result of head or chest trauma. The use of plastic baton rounds has decreased and, while a reduction in head injuries is noted, potentially serious chest injuries are still occurring. It is vital that guidelines on firing are adhered to. A large proportion of people who have been struck by plastic baton rounds do not attend an accident and emergency department and therefore doctors must be aware of patients with potentially serious injuries presenting late.
Adolescent↗
Team triage improves emergency department efficiency.
OBJECTIVE: To see whether three hours of combined doctor and nurse triage would lead to earlier medical assessment and treatment and whether this benefit would carry on for the rest of the day when normal triage had resumed. METHOD: Eight days were randomly selected; four for team triage and four for the normal nurse led triage. Team triage was coordinated by a middle grade or consultant from 9 am to 12 noon. Times to triage, to see a doctor, radiology, admission, and discharge were recorded. No additional medical or nursing staff were used and staffing levels were similar each day. All patients including blue light emergencies and minor injuries were included. RESULTS: Median times were significantly reduced (p<0.05) during the intervention to triage (2 min v 7 min, p = 0. 029), to see a doctor (2 min v 32 min, p = 0.029), and to radiology (11.5 min v 44.5 min, p = 0.029). Waiting times at midday were longer for patients in the non-intervention group. More patients were seen and discharged within 20 minutes in the intervention group (18 of 95 (19%) v 2 of 69 (3%) p = 0.0043). No significant knock on effect was demonstrable for the remaining 21 hours after the intervention ceased. CONCLUSION: Three hours of combined doctor and nurse triage significantly reduces the time to medical assessment, radiology, and to discharge during the intervention period. Waiting times at midday were shorter in the triage group. There was no significant knock on effect the rest of the day.
Appointments and Schedules↗
Two cases of biceps injury in bodybuilders with initially misleading presentation.
Two cases are reported of biceps injuries in body builders. In both cases the mechanism of injury is either unclear or initially misleading. One case went on to develop necrotising fasciitis, requiring extensive debridement after an initial diagnosis of a biceps haematoma. This report emphasises the difficulties inherent in differentiating necrotising and non-necrotising infections in the emergency department setting and highlights a subgroup of patients who may be at particular risk of delayed diagnosis.
Adult↗
Biological effects of long-duration, high-field (4 T) MRI on growth and development in the mouse.
The effects of long-duration, high-field magnetic resonance imaging (MRI) on fetal growth and postnatal development in mice were studied. Seven experimental groups of pregnant ICR mice were exposed for 9 hours on day 9 and/or day 12 post coitus (pc) to magnetic fields (4 T static, 5 T/sec switched gradient, and 0.2 W/kg radiofrequency at 170 MHz) associated with MRI conditions. Two experimental groups (sham and exposure groups) were exposed to a combination of ultrasound (day 9 pc, 3.25 MHz, focused) and MRI-associated fields (day 12 pc). No statistically significant changes in fetal growth were observed in the animals exposed to only MRI or ultrasound fields. However, in the combined ultrasound and MRI-exposed group, the fetal weight and crown-rump length were reduced compared with the sham and cage controls. These results suggest that MRI and ultrasound exposure well in excess of current clinical conditions can exert biological effects if applied at sensitive stages of fetal development.
Analysis of Variance↗
Measurements of acoustic properties of aqueous dextran solutions in the VHF/UHF range.
The acoustic properties of aqueous solutions of dextran are characterized in the frequency range of 70-400 MHz by the bio-ultrasonic spectroscopy system using an ultrasonic transmission comparison method. The attenuation, velocity, impedance, and density of aqueous dextran solutions, for six molecular weights in the range of 10,400-2,000,000 Da in the concentration range 520% by weight, are reported. All four parameters increase with increasing concentration. As the molecular weight increases, the attenuation coefficient increases and the velocity decreases. The precise frequency and molecular weight dependences of the acoustic properties of the solutions are readily determined by the system.
Dextrans↗
Ultrasound interaction with large unilamellar vesicles at the phospholipid phase transition: perturbation by phospholipid side chain substitution with deuterium.
The ultrasonic absorption, alpha lambda, as a function of temperature and frequency was determined in large unilamellar vesicles (LUVs) in which specific phospholipid side chains were deuterated. Deuteration significantly altered the temperature and frequency dependence of alpha lambda. The frequency change was especially marked, with decreased frequency and broadening of the ultrasound relaxation, even with only minor changes in the phase transition temperature. Deuteration decreased the Tm and enthalpy of the lipid phase transition, as shown by differential scanning calorimetry, whereas electron spin resonance showed that at and above the lipid phase transition, no differences in the mobility as a function of temperature were observed. These results show that the observed increase in ultrasonic absorption in LUVs at the phospholipid phase transition arises from the interaction of ultrasound with the hydrophobic side chains, probably coupling with structural reorganization of small domains of molecules, a process which is maximized at the phase transition temperature.
1,2-Dipalmitoylphosphatidylcholine↗
Selective clinical ultrasound signals mediate differential gene transfer and expression in two human prostate cancer cell lines: LnCap and PC-3.
Low intensity ultrasound signals, similar to that employed in clinical therapy, are found to mediate differential gene transfer and expression of the Green Fluorescence Protein (GFP) reporter in two human prostate cancer cell lines, LnCap and PC-3. Cell suspensions in the presence or in the absence of GFP (44.5nM) were treated at 37 degrees C under a standing wave condition. Cells were exposed to either continuous wave, 932.7kHz ultrasound, or to several independent bursts, each burst comprising a 20% duty cycle (932.7kHz) sine wave. The burst "repetition" frequency was varied from 10Hz to 10kHz in several different experiments and each treatment received a net identical ultrasound energy exposure. Transient GFP expression levels in viable cells were monitored by flow cytometry. The findings revealed a strong ultrasound tone-burst frequency dependence on the transfection efficiencies. Interestingly, the ultrasound signal parameters which are routinely employed in clinical therapy did not yield any statistically significant enhancement in transfection efficiency relative to their sham counterparts.
Cell Survival↗
Ultrasonic tissue characterization of infarcted myocardium by scanning acoustic microscopy.
The purpose of this study was to ultrasonically characterize infarcted human myocardial tissue at the microscopic level by scanning acoustic microscopy. Infarcted myocardial specimens from ten cases with acute myocardial infarction were studied. Specimens were formalin fixed, paraffin embedded and sectioned to 10-micron thickness. A specially developed scanning acoustic microscope system, operating in the 100- to 200-MHz ultrasound frequency range, was used for the measurements. The values of the attenuation constant were 0.94 +/- 0.04 dB/mm/MHz in normal myocardium, 0.71 +/- 0.12 dB/mm/MHz in degenerated myocardium, 0.88 +/- 0.47 dB/mm/MHz in granulation tissue and 1.75 +/- 0.11 dB/mm/MHz in fibrosis. The values of sound speed were 1620.2 +/- 8.2 m/s in normal myocardium, 1572.4 +/- 10.6 m/s in degenerated myocardium, 1590.2 +/- 32.5 m/s in granulation tissue and 1690.3 +/- 9.1 m/s in fibrosis. The ultrasonic properties of the diseased myocardium at the microscopic level will provide important information for ultrasonic tissue characterization at the macroscopic level.
Acoustics↗
Acoustic properties of egg yolk and albumen in the frequency range 20-400 MHz.
The acoustic propagation properties of egg yolk and albumen are characterized in the frequency range 20-400 MHz by the bioultrasonic spectroscopy system using an ultrasonic transmission comparison method. Significant differences in the attenuation, velocity, impedance, and density among yolk and thick and outer thin albumen are observed. The acoustic properties of 10% aqueous solutions of ovalbumin and bovine hemoglobin are also measured in order to investigate the contribution of proteins to the acoustic properties of albumen. The differences obtained between thick and outer thin albumen may be mainly due to their macromolecular level structural differences, as their constituents are nearly the same.
Acoustics↗
An experimentally obtainable heat source due to absorption of ultrasound in biological media.
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Body Temperature↗
Mediators of fibrinolysis in orthotopic liver transplantation.
Activation of fibrinolysis remains a clinical problem in orthotopic liver transplantation. We have measured tissue plasminogen activator (t-PA), plasmin and alpha-2-anti-plasmin (alpha 2AP) activities in plasma from 10 patients undergoing elective transplantation. t-PA activity increased during the anhepatic phase and immediately after graft reperfusion (p > 0.001). This increase could not be attributed to t-PA released by the donor liver. Overall transfusion requirements did not relate with either t-PA or alpha 2AP activities individually, but were strongly correlated with the ratio t-PA/ alpha 2AP (p > 0.02). These results suggest that routine prophylactic use of antifibrinolytic agents may be beneficial.
Adult↗
A simulation algorithm for ultrasound liver backscattered signals.
In this study, we present a simulation algorithm for the backscattered ultrasound signal from liver tissue. The algorithm simulates backscattered signals from normal liver and three different liver abnormalities. The performance of the algorithm has been tested by statistically comparing the simulated signals with corresponding signals obtained from a previous in vivo study. To verify that the simulated signals can be classified correctly we have applied a classification technique based on an artificial neural network. The acoustic features extracted from the spectrum over a 2.5 MHz bandwidth are the attenuation coefficient and the change of speed of sound with frequency (dispersion). Our results show that the algorithm performs satisfactorily. Further testing of the algorithm is conducted by the use of a data acquisition and analysis system designed by the authors, where several simulated signals are stored in memory chips and classified according to their abnormalities.
Acoustics↗
The effect of ultrasound exposure in utero on the development of the fetal mouse testis: adult consequences.
The effects of exposure in utero to 1 MHz, continuous-wave ultrasound on adult growth and testicular development in the mouse was investigated. The spatial peak temporal average intensity (ISPTA) employed ranged from 1 to 10 W/cm2, with exposure durations (t) of 200 s to 20 s. Exposures were made on days 9, 12 or 15 of gestation. Results showed an increase in postpartum deaths, an increase in the number of stillbirths, and a decrease in litter size when I2 t > or = 1125 W2 s/cm4, such that there was significant loss of pups. Birthweights of pups from nearly all dosage groups was significantly lower than that of the sham or cage control groups. Results also showed that males exposed to ultrasound in utero had decreased testis size and decreased daily sperm production ranging from 9% to 30%. This study showed that ultrasound exposure in utero is capable of disrupting fetal development and having potential subsequent effects on fertility in the adult male.
Animals↗
Acoustic properties of selected bovine tissues in the frequency range 20-200 MHz.
The acoustic properties of freshly excised bovine liver, heart muscle, and fat are characterized in the frequency range 20-200 MHz by the bioultrasonic spectroscopy system using an ultrasonic transmission comparison method. Significant differences are obtained in the attenuation coefficient, velocity, impedance, and density among these tissues. Measurements of aqueous solutions of bovine hemoglobin are also reported in order to compare the contribution of the protein content to the acoustic properties. The differences among the acoustic properties of liver and heart muscle can be described in terms of their protein contents and other molecular constituents.
Acoustics↗
In vivo liver differentiation by ultrasound using an artificial neural network.
A pattern recognition algorithm and instrumentation for in vivo ultrasound human liver differentiation are presented. An available 16-MHz microprocessor-based data acquisition and analysis system with 6-bit resolution is used to capture, digitize, and store the backscattered ultrasound signal. The algorithm is based on a multilayer perception neural network using the backpropagation training procedure. The network is implemented to differentiate between normal and abnormal liver. Data earlier obtained from 18 volunteers with normal liver history and from 12 volunteers with liver abnormalities are used to test the algorithm. The power spectra of the backscattered signal from depths of 5, 6.5, and 8 cm in the liver are calculated. The acoustic attenuation coefficient is calculated by the log spectral difference technique over the frequency range from 1.5 to 4.5 MHz. The change of speed of sound with frequency (dispersion) is estimated over the 3-MHz bandwidth. The attenuation and velocity dispersion are used as differentiation features. The results show that of the 22 tested cases, the system differentiated correctly 19 and 20 cases when using the attenuation and the velocity dispersion, respectively. The average magnitude of dispersion of liver is estimated to be 1.67 +/- 0.1 m/s/MHz and about 2.3 +/- 0.18 m/s/MHz in the normal and abnormal cases, respectively. The overall performance of the system for liver differentiation is 91% for normal cases, and 86% for abnormal cases. The data files are also differentiated using the nearest neighbor statistical classifier. The results show that of the 30 tested cases, 23 files are differentiated correctly using the attenuation coefficient.
Humans↗
Acoustic non-linearity method for estimating the ratio of bound to free water of biological media.
The acoustic non-linear properties of bound and free water in biological media are treated based on their structural differences. A model describing the different effects of bound and free water in protein-water solutions and in biological media is proposed. The ratio of bound to free water can be estimated from this model from measurements of the acoustic non-linearity parameter B/A, the sound speed, and the density of the specimens.
Acoustics↗
Ultrasonic absorption frequency dependence of two widely used anti-cancer drugs: doxorubicin and daunorubicin.
Low intensity ultrasound (approximately 10(-6) W cm-2) in the frequency range 0.5-6.0 MHz was employed to investigate the ultrasound absorption properties of doxorubicin (DOX) at several temperatures. At physiological temperatures, we found enhanced ultrasound absorption from DOX, and its closely related analogue daunorubicin (DNR), in the upper kilohertz frequency range. The findings do not conform to classical theory of ultrasound absorption, thus suggesting an ultrasound coupling with the drug molecules via structural and/or chemical relaxation processes. The absorption spectra are analysed from the point of view of the non-classical theory of sound absorption due to physical and/or chemical relaxations. Only one spectral difference between the two anti-cancer agents is observed, around 2 MHz, and may be attributed to the sole difference in the chemical make-up of the side chain of the two antibiotics.
Absorption↗