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At least 19 recordsLinked to original sources
PubMed1992

Biomechanical aspects of a fluid percussion model of brain injury.

The fluid percussion model is in widespread use for the study of brain injury. However, the tissue deformation characteristics of the model have not been determined. Studies have suggested that at high levels of fluid percussion, the fluid percussion model is primarily a model of brainstem injury. It was proposed that this occurs as a direct result of the volume influx to the cranial vault at the moment of impact. This study examines the biomechanical deformation produced by the fluid percussion model. The purpose of this investigation was to describe the regional strain distribution in brain tissue at the moment of impact and to determine the effect of volume efflux produced by the percussion device. A cat skull was sectioned parasagittally and filled with an optically transparent gel. A grid pattern was painted in the midsagittal plane and was used to record the surrogate brain tissue deformation in response to fluid percussion loading. Motion of the grid pattern at low and high levels of fluid percussion loading was recorded using a high-speed camera, and a series of photographs developed from the high-speed film were analyzed to determine the intracranial strain distribution at these loading levels. The results of these studies indicated that the maximum site of strain was located in the region of the lower brainstem and that deformations were negligible in other regions of the brain. These studies provide an explanation for the pathophysiologic results obtained in a parallel series of experiments from which it was concluded that high-level fluid percussion is predominantly a model of lower brainstem injury.

Animals↗
PubMed1992

Consistency of sternal percussion performed manually and with mechanical thumper.

Auscultatory percussion is a technique that is potentially useful to study the acoustic behaviour of the chest. However, finger percussion, as used in this technique, has not been previously assessed for consistency. We calculated the intrasubject variability and short-term reproducibility of this technique in 10 healthy subjects. We examined several indices of the output sound of two series of sternal percussion manoeuvres performed one hour apart by the same examiner. The results were compared to those obtained during sternal percussion performed by a mechanical thumper. Consistency for both finger and thumper percussion varied from 4.8-20.6 (coefficients of variation) for various acoustic indices. For thumper percussion, the average results were not significantly different from those of finger percussion. We conclude that finger percussion of the sternum is sufficiently consistent to be used as a tool to investigate the acoustic behaviour of the chest.

Acoustics↗
PubMed1992

Accuracy of percussion of the left cardiac border.

UNLABELLED: The purpose of this study was to determine the accuracy of percussion of the left cardiac border. Sixty-six adult patients were studied. The left cardiac border as determined by percussion and marked with a calibrated lead marker was compared with that obtained by a chest X-ray. The error in locating the left cardiac border by percussion ranged from underestimating by 5.0 cm to overestimating by 5.5 cm. The mean absolute error was 1.6 cm (SD = 1.6 cm). In 74% (49/66) and 85% (56/66) of the patients the percussed border was within 1.0 and 2.0 cm, respectively, of that established by X-ray. In 24 of the 66 cases, a second examiner also independently percussed the left cardiac border. The differences between the location determined by the two observers ranged from 0 to 4 cm with a mean difference of 1.2 cm (SD = 1.0 cm). CONCLUSION: Percussion can accurately locate the left cardiac border in the adult patient and is a reproducible technique.

Adult↗
PubMed1979

Non-penetrative percussion stunning of sheep and calves.

Attempts were made to stun lambs, adult sheep and calves by a non-penetrative percussive method. Using an adapted Cash pistol, with a concave padded impact head, impulses were produced which effectively stunned 96% of lambs but induced brain haemorrhages in up to 7% of the animals. The signs and duration of an effective percussive stun were observed and recorded. Calves were readily stunned by percussive methods but brain haemorrhages frequently occurred. Impulses sufficiently large to stun adult sheep, with a non-penetrating impact head, were produced from an adapted Hantover pneumatic cattle stunner. Comparative trials, using electrical and percussive stunners, demonstrated a significant decrease in the prevalence of blood splash in lambs stunned by percussion.

Abattoirs↗
PubMed1992

Mobility and percussion sound of healthy upper incisors and canines.

In order to evaluate the correlation between mobility and percussion sound, 126 upper incisors and canines in 21 student volunteers were measured by means of the Periotest (Siemens), by evaluating the percussion sound subjectively and by analyzing its spectrum. The attenuation time and frequency of the sound were measured for each tooth. A logical mobility and percussion sound existed in accordance with the sizes of the teeth. Spearman correlation coefficients close to 1.00 were noted in individual cases between the Periotest and the three other tests describing the percussion sounds.

Adult↗
PubMed1977

Abdominal examination: role of percussion and auscultation.

Clinicians should not minimize or overlook the importance of percussion of the liver and the spleen and of auscultation over the liver as routine parts of abdominal examination. Splenic percussion can be used to detect splenomegaly even before the spleen becomes palpable. The span of liver dullness on percussion can be compared with established normal standards to detect hepatomegaly or alterations caused by cirrhosis. A systolic bruit, a friction rub, or a venous hum detected by auscultation over the liver is an important sign of liver disease.

Abdomen↗
PubMed1977

Two new methods of percussion.

Existing methods of percussion have been reviewed and their drawbacks enumerated. Two new methods of percussion, single hand, and four methods have been described. It has been claimed that the new methods of percussion are better than the existing methods.

Humans↗
PubMed1979

Physiologic effects of chest percussion and postural drainage in patients with stable chronic bronchitis.

The effects of a 30-minute period of chest percussion and postural drainage were compared to a sham treatment (infrared lamp) in 35 patients with stable chronic bronchitis and to a period of directed coughing in 11 of these same patients. There were no differences in subjective responses or arterial blood gas levels following therapy. Spirometric studies showed small improvements over baseline values following either treatment but no difference between active and sham treatments. The volume of sputum expectorated during percussion and drainage was significantly greater than during the infrared warming (5.5 vs 1.4 ml) or during the directed coughing (9.0 vs 3.5 ml). Although chest percussion and postural drainage are effective in augmenting the volume of expectorated sputum, no significant alternations in air flow or gas exchange after two hours were demonstrated.

Adult↗
PubMed1976

Fluid-percussion model of mechanical brain injury in the cat.

Mechanical brain injury was produced in 36 cats with a fluid-percussion model in which brain damage or dysfunction is produced by a single, brief, hydraulically-induced pressure transient that is conducted through the brain. Fluid-percussion injury induce elastic deformation of the brain resembling the brain deformation known to occur following head impact. Physiological responses and pahtological changes following injury were expressed as a function of peak pressure. Macroscopic central nervous system lesions concentrated at the pontomesencephalic junction, cervicomedullary junction, and in the cerebellar tonsils were consistently observed at and above 2.6 atmospheres (atm). At higher levels of injury (greater than or equal to 3.2 atm) there was extensive basal subarachnoid hemorrhage. At very high levels of injury (greater than 4.0 atm) hemorrhagic contusions were noted at the cerebral hemisphere impact site. A spectrum of neuronal alterations was identified in the damaged areas. Computer analysis showed correlation of electroencephalographic (EEG) changes with the neuropathological changes, since EEG recovery became severely impaired above 2.6 atm. No EEG changes were noted below 1.5 atm. From 1.5 to 2.2 atm there was a physiological response to injury but no significant changes were seen on neuropathological examination. This range of injury should permit further studies of the more subtle changes following mechanical brain injury without intraparenchymal hemorrhage or subarachnoid hemorrhage. The fluid-percussion model relates brain deformation following mechanical loading to a single pressure transient that is easily measured and controlled. Further quantitative investigation into the pathobiology of mechanical brain injury following graded brain deformation is thus made possible.

Animals↗
PubMed1992

Expression of c-fos in the hippocampus following mild and moderate fluid percussion brain injury.

An oncoprotein mediator of gene expression, c-fos, was evaluated in the central fluid percussion model of traumatic brain injury (TBI). Since hippocampal CA1 neurons are particularly vulnerable to TBI, we hypothesized that TBI may produce pathobiologic changes in CA1, in part, by alterations in gene expression through c-fos. Sprague-Dawley rats were subjected to mild (1.0 atm) or moderate (2.1 atm) fluid percussion TBI or sham injury. At 15 min, 1 h, and 24 h after injury (or sham injury), sections from middorsal hippocampus were immunostained with antibodies to c-fos, and c-fos-positive CA1 neurons were counted. As predicted, c-fos was localized in the nuclei of CA1 pyramidal neurons. However, the intensity of label was not equal over all CA1 neurons. Cells with high-intensity c-fos label were more prevalent after mild TBI. The number of c-fos-labeled CA1 neurons was increased at 15 min after both mild and moderate TBI relative to paired sham controls. Counts of c-fos-positive neurons remained significantly elevated at 1 h postinjury only after mild TBI. By 24 h postinjury, the number of c-fos-positive cells at both injury levels was not different from sham controls. No difference was observed between the number of c-fos-positive cells in naive and sham controls. However, label intensity was slightly less in the naive cases. These results suggest that the pathobiologic changes at early intervals following mild or moderate TBI may involve c-fos alteration of gene expression and that c-fos expression may be differentially regulated as a function of injury level.

Animals↗
PubMed1976

The influence of percussion, occlusion and mastication on the occurrence of silent periods in masseter muscle activity.

The occurrence of silent periods in masseter muscle activity was investigated during percussion of the bony structures of the head and neck, during occlusion of the teeth on surfaces of varying hardness, and during chewing of different food-stuffs. Silent periods were demonstrated on percussion during isometric and isotonic contraction of the masseter muscles and the occurrence of silent periods was influenced by the force of occlusion and by the nature of the surface contacted. Mandibular velocity was investigated during tapping and chewing sequences by ultra-high-speed cinematography, but it was not found possible to identify a critical change in mandibular velocity associated with the occurrence of silent periods. More silent periods were observed during the chewing of hard foods than of soft foods and there were more silent periods near the beginning of chewing sequences than towards the end. Differences in latency and duration of silent periods were observed in relation to artificial changes in the occlusion.

Dental Occlusion↗
PubMed1979

Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry.

Piorry was born in Poitiers on 31 December 1794. As a medical student he served in the Napoleonic war in Spain. His teachers in medicine included Corvisart, Bayle, Broussais, and Magendie; he qualified in 1816 with an MD thesis: "On the danger of reading medical text books by the laity"! Laënnec's invention of the stethoscope (1816) and De l' Auscultation Médiate (1819) inspired Piorry to make an analogous contribution to the technique of percussion (which had been originally described by Auenbrugger in his Inventum Novum in 1761 and translated from the Latin into French by Corvisart in 1808). This led to Piorry's invention in 1826 of the pleximeter (le plessimétre) to help outline the internal organs (l'organographisme), which he described inDe la Percussion Médiate (1828). Piorry became renowned as a professor of medicine in many of the great Parisian hospitals (Charité, Pitié, and Hôtel Dieux). In 1832 he was appointed to L'Hospice de la Salpétrière, where he held a famous course of clinical lectures. He wrote prolificly on many aspects of medicine and published more than twenty books. He was, in addition, a poet of some distinction, and wrote a remarkable long poem Dieu, L'Ame et la Nature (1853). Piorry held his neologisms-for example, toxin, toxaemia, septicaemia, etc.-are still in use. This, together with the mixed reception that his advocacy of pleximetry received from his medical contemporaries, made him a controversial figure. He died on 29 May 1879.

Auscultation↗
PubMed1979

The arts of percussion and auscultation of the chest re-examined.

Clinical teaching of percussion and auscultation is examined critically, and it is suggested that there is confusion on the subject both in textbooks and in the minds of clinicians and students. Percussion should be viewed more in terms of 'feel' than 'sound', and thus a classification of 'hard', 'intermediate' and 'soft' dullness is introduced. As regards auscultation, a plea is made for differentiation between obstructed and non-obstructed consolidation of lobes, a point recognized by some clinicians, but not enunciated with clarity by teachers. The differences between the clinical findings in obstructive consolidation of the upper and lower lobes are discussed. The importance of distinguishing between tracheal and bronchial breathing is emphasized.

Auscultation↗
PubMed1992

Brain levels of polyethylene glycol-conjugated superoxide dismutase following fluid percussion brain injury in rats.

Polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) is being explored as an agent to reduce oxygen radical-mediated damage following brain injury. Yet little is known concerning the site of action of IV-administered PEG-SOD or the capacity of this conjugated enzyme to enter the brain. The purpose of this study was to determine the brain content of PEG-SOD in normal and fluid percussion injured rats. The fluid percussion device was attached over the right parietal cortex and a moderate (2.0 atm) intensity injury was produced. PEG-SOD was conjugated with 125I and given (2000 U/kg, 5 microCi/kg) to rats either 30 min before or 30 min after brain injury. Another group received [125I]PEG-SOD but was not injured. Plasma and left and right brain hemispheres were counted for [125I]PEG-SOD. Plasma levels of [125I]PEG-SOD declined similarly in all three groups during the 90-min period after IV administration. Brain [125I]PEG-SOD was low in control animals (0.034 U/g wet wt). In animals given PEG-SOD after injury the brain level was elevated sixfold in both the left and right hemispheres, compared to control. In rats given the drug before injury, [125I]PEG-SOD was 10 times control level in the right hemisphere, which is the side on which the injury device is attached, and 6 times control level in the left hemisphere. We conclude that traumatic brain injury produces an increase in brain PEG-SOD. The exact cellular site of the increased brain PEG-SOD remains to be clarified.

Animals↗
PubMed1979

Comparative trial of manual and mechanical percussion technique with gravity-assisted bronchial drainage in patients with cystic fibrosis.

Chest physiotherapy still remains one of the most important aspects in the treatment of chest complications of cystic fibrosis. A mechanical device that allows the patient with cystic fibrosis to do his own chest physiotherapy will be of great benefit if it is as effective as manual percussion. 14 patients with cystic fibrosis using mechanical and manual percussion physiotherapy were studied by measuring sputum volumes, and FEV and FVC. Results with mechanical percussor were as good as with the manual percussor and, therefore, it would be reasonable for the older patient to use the former on his own.

Adolescent↗
PubMed1978

Myokymia, muscle hypertrophy and percussion "myotonia" in chronic recurrent polyneuropathy.

Three unusual features were observed in a patient with chronic relapsing polyneuropathy: myokymia, muscle hypertrophy, and prolonged contraction in response to muscle percussion. Low nerve conduction velocity and conduction block were demonstrated in all motor nerves tested, indicating a demyelinating peripheral neuropathy. Myokymia was caused by spontaneous motor unit activity which was shown to originate in peripheral nerves, since it persisted after nerve block and was abolished by regional curarization. Muscle hypertrophy was attributed to increased peripheral nerve activity, and the prolonged contraction of muscle in response to direct percussion was attributed to irritability of intramuscular nerve terminals.

Adult↗
PubMed1975

An auditory-motor percussion test for differential diagnosis of children with communication difficulties.

Experience with children who have communication difficulties, are often hard to reach, and present severe barriers to treatment and testing led to the development of an auditory-motor percussion test designed to help distinguish children who show organicity from those who do not. Results of a normative study of 144 children tested in settings for the normal child and 84 in settings for disturbed children supported the hypothesis that the presence of structural alteration in the central nervous system is probable if subject (aged 4 to 7) is unable to tap a rhythmic tonal pattern. With the use of simple percussion instruments in a special method for administering the new procedure, the test can be used as an alert to hidden neurological damage in children over 4 and inaccessible to traditional testing.

Adolescent↗
PubMed1992

Breakdown of the blood-brain barrier after fluid percussion brain injury in the rat: Part 2: Effect of hypoxia on permeability to plasma proteins.

Clinical studies have demonstrated that hypoxia after severe brain injury is common and significantly worsens neurologic outcome. We have, therefore, developed a rat model of posttraumatic hypoxic injury in order to identify the pathophysiologic responses after head injury that are worsened by this secondary insult. We examined the effect of hypoxia after brain injury on permeability of the blood-brain barrier to plasma proteins. Animals were divided into two experimental groups: group I (impact alone) and group IH (impact plus hypoxia). Rats were subjected to a lateral fluid percussive brain injury (4.8-5.2 atm). Animals in group IH were exposed to hypoxic conditions (10% O2) for 45 min immediately after injury. In each group, vascular permeability to endogenous immunoglobulins (IgG) and to horseradish peroxidase (HRP) was examined at the light microscopic level. IgG was immunolocalized in brain sections at 1-24 h after injury. In other studies, HRP was given i.v. either before impact or 10 min before killing. Permeability to this protein was assessed at 1-72 h after injury. The distribution of extravasated proteins was similar between the experimental groups at 1 h postinjury. Pronounced abnormal permeability to IgG and HRP (given before impact) occurred in discrete regions throughout both the ipsilateral and contralateral hemispheres. By 6 h after injury, a differential response of the blood-brain barrier was noted between groups I and IH. Widespread leakage of proteins was observed in the injured hemisphere in group IH. This finding was in sharp contrast to group I, in which extravasated proteins remained more localized in the injured hemisphere. The time course for reestablishment of the blood-brain barrier to HRP (given before killing) was determined. The impact site remained permeable to HRP up to at least 72 h postinjury within groups I and IH. In group I, the blood-brain barrier was reestablished in the parasagittal cortex and deep cortical layer by 6 h postinjury. In contrast, the blood-brain barrier in group IH was not restored in similar brain regions until 24 h postinjury. These studies demonstrate that (1) hypoxia after brain injury exacerbates the regional breakdown of the blood-brain barrier to circulating proteins, (2) this influence of hypoxia on permeability is not apparent immediately after injury but rather is expressed at 6 h after injury, and (3) hypoxia after traumatic brain injury delays recovery of the blood-brain barrier. These findings suggest that secondary posttraumatic hypoxia contributes to the vascular pathogenesis of brain injury.

Animals↗