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PubMed2004

High-frequency percussive ventilation: an alternative mode of ventilation for head-injured patients with adult respiratory distress syndrome.

BACKGROUND: Adult respiratory distress syndrome develops in up to 20% of patients with severe head injury. This complicates the treatment of head-injured patients because lung-protective strategies such as high positive end-expiratory pressure (PEEP) and permissive hypercapnia may increase intracranial pressure (ICP) and reduce cerebral perfusion pressure. The use of high-frequency percussive ventilation (HFPV) is an alternate mode of ventilation that may improve oxygenation for head-injured patients while also lowering ICP. METHODS: Clinical data were collected retrospectively over a 1-year period. Patients were included if they had a severe traumatic brain injury with a Glasgow Coma Score (GCS) of 8 or lower, a ventriculostomy drain for ICP measurement and cerebral spinal fluid drainage, and adult respiratory distress syndrome. Patients were switched from conventional mechanical ventilation to HFPV at the discretion of the attending trauma surgeon. Data for partial pressure of oxygen to fraction of inspired oxygen (PF) ratio, peak inspiratory pressure (PIP), ICP, partial pressure of carbon dioxide level (PCO2), PEEP, and mean airway pressure were compared before and then 4 and 16 hours after institution of HFPV therapy. RESULTS: A total of 10 patients met study criteria. Data were expressed as mean +/- standard error. There was an increase in PF ratio (91.8 +/- 13.2 vs. 269.7 +/- 34.6; p < 0.01), PEEP (14 +/- 2.5 vs. 16 +/- 3.5), and mean airway pressure (20.4 +/- 4.8 vs. 23.6 +/- 6.8) 16 hours after institution of HFPV. There was a decrease in ICP (30.9 +/- 3.4 vs. 17.4 +/- 1.7; p < 0.01), PC02 (37.7 +/- 4.1 vs. 32.7 +/- 1.1; p < 0.05), and PIP (49.4 +/- 10 vs. 41 +/- 7.9; p < 0.05) at 16 hours. Overall mortality was 10%. CONCLUSIONS: Therapy with HFPV produced a significant improvement in oxygenation with a concomitant reduction in ICP during the first 16 hours. This therapy may represent an important new method for the management of adult respiratory distress syndrome among head-injured trauma patients, although the long-term outcome of HFPV still needs evaluation.

Adult↗
PubMed2005

Mercaptoethylguanidine inhibition of inducible nitric oxide synthase and cyclooxygenase-2 expressions induced in rats after fluid-percussion brain injury.

The present study examined the temporal expression of nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 in rat brains after traumatic brain injury (TBI). We studied the effects of mercaptoethylguanidine (MEG), a dual inhibitor of the inducible iNOS and COX with scavenging effect on peroxynitrite, on physiologic variables, brain pathogenesis, and neurologic performance in rats after a lateral fluid percussive-induced TBI. Mean arterial blood pressure and percentage cerebral tissue perfusion in MEG-treated TBI rats showed significant improvement when compared with TBI rats. Immunohistochemical analysis showed a marked number of iNOS and COX-2 immunopositive cells in the cerebral cortex ipsilateral to the injury in TBI rats when compared with MEG-treated TBI rats. MEG also significantly decreased the number of hyperchromatic and shrunken cortical neurons when compared with TBI rats' brain nitrate/nitrite, and prostaglandin E2 levels were attenuated in MEG-treated TBI rats when compared with TBI rats. It is therefore suggested that treatment of MEG via inhibition of iNOS and COX-2 might contribute to improved physiologic variables, neuronal cell survival, and neurologic outcome after TBI.

Animals↗
PubMed1990

Auditory correlates of perceived mallet hardness for a set of recorded percussive sound events.

A psychophysical investigation of timbre was undertaken with the intent of deriving quantitative results that could be useful in musical applications. Recordings of metal objects being struck with percussion mallets were rated by subjects on a unidimensional perceptual scale of perceived mallet hardness. Four acoustical parameters of the attack portion (first 325 ms) were defined and evaluated as predictors of perceived mallet hardness rating. To measure these parameters, a critical-band filter bank was employed. Two curves were extracted from the filter-bank output: (1) spectral level (log of area under spectrum) over time, and (2) spectral centroid over time. For each curve, two parameters were measured: the mean and the slope of the spectral level curve, and the mean and the time-weighted average of the spectral centroid curve. Multiple regression analysis was used to relate the perceptual ratings to these four acoustical parameters, and a good fit was achieved (multiple R-squared = 0.725, F = 1135.8, p less than 0.01). The resulting function is suitable for quantitatively predicting the perceptual dimension of perceived mallet hardness.

Adult↗
PubMed1997

Uncoupling of local cerebral glucose metabolism and blood flow after acute fluid-percussion injury in rats.

We assessed local cerebral glucose metabolism (lCMRGlc) and blood flow (lCBF) interrelationships in the first hour after parasagittal fluid-percussion head injury (FPI) in rats. Matched series were studied autoradiographically for lCMRGlc and lCBF with 2-[14C]deoxyglucose and 14C-labeled iodoantipyrine, respectively. Three-dimensional autoradiographic-image mapping was to generate average data sets from which a mean ICMRGlc-to-lCBF ratio data set was derived. lCBF in neocortical regions ipsilateral to the trauma were depressed, on average, by 44% compared with sham-FPI rats, whereas contralateral lCBF values were not altered. By contrast, ICMRGlc was elevated in many cortical and subcortical sites of both hemispheres; this amounted to 1.3- to 1.4-fold increases in neocortical regions in the thalamus and 1.6- to 1.7-fold increases in the hippocampus. The lCMRGlc-to-lCBF ratio data revealed striking elevations both ipsilateral (P = 7 x 10(-7) and contralateral to the FPI (P = 0.003). The extent of metabolism-flow uncoupling, on average, amounted to 2.5-fold in the ipsilateral hippocampus and neocortex and 1.7-fold contralaterally. The loci of pronounced metabolism-flow dissociation corresponded closely to the previously documented histological distribution of neuronal necrosis. Our findings resemble events occurring in the acute focal ischemic penumbra and suggest that similar injury mechanisms may be operative.

Acute Disease↗
PubMed1998

The intrapulmonary percussive ventilator and flutter device compared to standard chest physiotherapy in patients with cystic fibrosis.

Stasis of viscid secretions in cystic fibrosis (CF) leads to chronic infection, inflammation, and lung destruction. Chest physiotherapy (CPT) has been used for many years to assist in the removal of these secretions. However, the need for independently administered CPT exists, particularly for adolescents and the older CF patient. Two devices, the intrapulmonary percussive ventilator (IPV) and the Flutter device (Flutter) have been promoted for this purpose. This study compares these devices to standard, manual CPT. There was no difference in sputum quantity produced with any method studied. Transiently lower oxygen saturation was noted with standard CPT compared with the IPV and Flutter. Inconsistent but significant improvements in flow rates were noted with the two devices compared to standard CPT. Important trends to lower lung volumes, probably indicating decreased air trapping, were also noted with all three therapies at 1 and 4 hours after administration. There were no adverse effects with any treatment regimen. Larger and longer studies of these devices compared to standard CPT and with each other are warranted to assess their value for independent administration of CPT in CF patients and to determine long-term effects on maintenance of pulmonary function.

Adolescent↗
PubMed2005

Percussion hole drilling of metals with a fourth-harmonic Nd:YAG laser studied by defocused laser speckle correlation.

Defocused speckle correlation is introduced as a tool for measuring the response in metal sheets during percussion laser drilling. For this procedure the fourth-harmonic Nd:YAG wavelength (266 nm) was used in pulsed mode. The method provides a cost-efficient and robust alternative to speckle interferometry for the study of the small deformations that appear during laser processing. The accuracy was shown to be of the order of a few tens of microradians for the tilt component that is measured, which translates to a few nanometers in deflection when the component is spatially integrated. In the measurements, deflections in the form of craters as large as 50 nm were detected on the back sides of silver and copper sheets. The diameters of the craters were 300 microm in the silver and 150 microm in the copper sheet; the output diameter of the hole was -5 microm.

Journal Article↗
PubMed2005

Investigation of laser percussion hole drilling by use of speckle correlation.

In this paper speckle correlation is introduced as a tool to investigate the heat-influenced area during material processing with laser light. Two materials were investigated, a pure silver sheet and a sheet of SiC-diamond composite. The processing laser used in the experiments was a diode-pumped acousto-optical Q-switched Nd:YAG laser that allowed percussion hole drilling to be performed using green light through a second-harmonic crystal. The measurements were performed using a continuous-wave He-Ne laser and a digital camera. The experimental results show that the heat-influenced area is approximately 5000 times larger than the actual hole being drilled and that it reaches a steady-state condition toward the end of the processing cycle.

Journal Article↗
PubMed1999

High-frequency percussive ventilation improves oxygenation in patients with ARDS.

STUDY OBJECTIVES: To evaluate changes in respiratory and hemodynamic function of patients with ARDS and requiring high-frequency percussive ventilation (HFPV) after failure of conventional ventilation (CV). DESIGN: Retrospective case series. SETTING: Surgical ICU (SICU) and medical ICU (MICU) of an academic county facility. MEASUREMENTS AND RESULTS: Thirty-two consecutive patients with ARDS (20 from SICU, 12 from MICU) who were unresponsive to at least 48 h of CV and were switched to HFPV were studied. Data on respiratory and hemodynamic parameters were collected during the 48 h preceding and the 48 h after institution of HFPV and compared. Between the period of CV and the period of HFPV, the ratio of PaO2 to the fraction of inspired oxygen (F(IO2)) increased ([mean+/-SE] 130+/-8 vs. 172+/-17; p = 0.027), peak inspiratory pressure (PIP) decreased (39.5+/-1.7 vs. 32.5+/-1.9 mm Hg; p = 0.002), and mean airway pressure(MAP) increased (19.2+/-1.2 vs. 27.5+/-1.4 mm Hg; p<0.001). The rate of change of PaO2/F(IO2) per hour was also significantly improved between the two periods. The same changes in PaO2/F(IO2), PIP, and MAP were observed when the last value recorded while the patients were on CV was compared with the first value recorded after 1 h of HFPV. This improvement was sustained but not amplified during the hours of HFPV. The patterns of improvement in these three parameters were similar in SICU and MICU patients as well as in volume-control and pressure-control patients. There were no changes in hemodynamic parameters. CONCLUSION: The HFPV improves oxygenation by increasing MAP and decreasing PIP. This improvement is achieved soon after institution of HFPV and is maintained without affecting hemodynamics.

Adult↗
PubMed2004

Comparison of lung deposition in two types of nebulization: intrapulmonary percussive ventilation vs jet nebulization.

BACKGROUND: So-called intrapulmonary percussive ventilation (IPV), frequently coupled with a nebulizer, is increasingly used as a physiotherapy technique; however, its physiologic and clinical values have not been rigorously assessed. STUDY OBJECTIVE: To compare in vitro and in vivo characteristics of the nebulizer of the IPV device (Percussionaire; Percussionaire Corporation; Sandpoint, ID) with those of standard jet nebulization (SST) [SideStream; Medic-Aid; West Sussex, UK]. DESIGN: Aerodynamic particle size was studied by an cascade impactor. The deposition of (99m)Tc-diethylenetriaminepenta-acetic acid was measured in 10 healthy subjects by tomoscintigraphy during spontaneous breathing with both nebulizers. MEASUREMENTS AND RESULTS: The mass median aerodynamic diameter (0.2 micro m vs 1.89 micro m for IPV and SST, respectively) and the fine-particle fraction (16.2% vs 67.5%, respectively) were significantly smaller with IPV. In vivo, respiratory frequency (RF) was lower with the IPV device (10.1 +/- 3.4 breaths/min vs 14.6 +/- 3.4 breaths/min, p = 0.002). Whole-body deposition was significantly higher with IPV (15.63% vs 9.31%), but it was due to a higher extrapulmonary deposition. Although intrapulmonary deposition (IPD) was not different with both devices (4.20% for SST vs 2.49% for IPV), it was much more variable with IPV, compared to SST. The penetration index into the lung was higher with IPV than SST when normalized for RF (0.045 +/- 0.018 breaths/min vs 0.026 +/- 0.013 breaths/min, p = 0.007). CONCLUSION: The two techniques showed comparable lung deposition despite a large difference in particle size. However, IPV IPD was too variable and thus too unpredictable to recommend its use for drug delivery to the lung.

Administration, Inhalation↗
PubMed2004

Enhanced alveolar clearance with chest percussion therapy and positional changes during whole-lung lavage for alveolar proteinosis.

Pulmonary alveolar proteinosis has traditionally been treated with whole-lung lavage (WLL). The literature describes a variety of techniques used in performing the WLL, including mechanical vs manual chest percussion, use of prone positioning, and variances in lavage volume. We have quantified and compared the effective alveolar clearance for each component of the lavage by measuring the dry weight of material in the lavage effluent. We measured this in five patients who underwent six consecutive WLLs at the University of Pittsburgh Medical Center. We performed the lavage in the following three stages: stage I, passive drainage; stage II, assisted clearance; and stage III, positional clearance. Aliquots of lavage effluent were centrifuged to determine the dry weight of material present in sequentially recorded bottles within each stage. At the initiation of each augmentation, there was a statistically significant improvement in the clearance of material (stage II, p = 0.009; stage III, p = 0.012). Furthermore, we show that lipoproteinaceous material is present in the lavage effluent in all stages of latter portions of the lavage. The effective removal of material would be expected to have an impact on the physiologic and clinical response to WLL. This finding emphasizes the importance of performing an adequate and standardized lavage.

Bronchoalveolar Lavage↗
PubMed2006

Effect of wrist and forearm training on linear bat-end, center of percussion, and hand velocities and on time to ball contact of high school baseball players.

This study examined the effects of 12 weeks of wrist and forearm training on linear bat-end velocity (BV), center of percussion velocity (CV), hand velocity (HV), and time to ball contact of high school baseball players. Forty-three baseball players were randomly assigned by a stratified sampling technique to 1 of 2 training groups. Group 1 (n = 23) and group 2 (n = 20) performed the same full-body resistance exercises while training 3 days a week for 12 weeks according to a stepwise periodized model. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks. Wrist and forearm strength were measured pre- and posttraining. Linear BV, CV, HV, and time to ball contact were recorded pre- and posttraining by a motion-capture system. A 3 repetition maximum (RM) parallel squat and bench press were measured at baseline and after 4, 8, and 12 weeks of training. Both groups showed statistically significant increases (p < or = 0.01) in linear BV, CV, and HV (m.s(-1) +/- SD) after 12 weeks of training; however, there were no differences between the 2 groups. Both groups statistically increased wrist and forearm strength (p < or = 0.05). Group 2 had statistically greater increases (p < or = 0.05) in 10 of 12 wrist and forearm strength measures than did group 1. Both groups made statistically significant increases in predicted 1RM parallel squat and bench press after 4, 8, and 12 weeks of training; however, there were no differences between groups. These data indicate that a 12-week stepwise periodized training program can significantly increase wrist and forearm strength, linear BV, CV, and HV among high school baseball players. However, increased wrist and forearm strength did not contribute to further increases in linear BV, CV, or HV.

Adolescent↗
PubMed2004

Doing anger differently: a group percussion therapy for angry adolescent boys.

This paper describes Doing Anger Differently (DAD), a group treatment for young adolescent boys with high levels of anger. The approach is school-based, 10 weeks long, and utilizes music in the form of percussion to engage this difficult to treat population into treatment and to represent the experience of anger. A tri-level intervention is described: the experience of anger and its influence on action; the formation of meaning and identity resulting from anger and aggression; and the emphasis on group work and the interpersonal basis of anger. Techniques used throughout the group are discussed and illustrative case vignettes are provided.

Adolescent↗
PubMed2003

Multiple immunostaining methods to detect traumatic axonal injury in the rat fluid-percussion brain injury model.

Immunohistochemistry using beta-amyloid precursor protein (APP) N-terminus antibodies is routinely used to detect traumatic axonal injury (TAI). The temporal and regional distributions of APP C- and N-terminus immunoreactivity were investigated in rats with experimental brain injury and compared to distribution of neurofilament (NF) immunoreactivity. Male Sprague-Dawley rats underwent right lateral fluid-percussion (FP) brain injury or sham injury. Six FP injury rats and two control rats were transcardially fixed with 10% formalin at 1, 6, 24, and 48 hours, and 1 and 2 weeks after injury and serial 6 microm-thick paraffin sections were prepared. At 6 hours after injury, APP C-terminus immunostaining labeled small neurons and axonal deposits in the injured parasagittal cortex, striatum, thalami, and dorsal medulla, whereas APP N-terminus and NF immunostaining showed few axonal deposits in the parasagittal cortex. At 24-48 hours post-injury, marked axonal damage, including axonal swelling and bulbs, was observed in the injured cerebral hemisphere, cerebellar white matter, and medulla. NF immunostaining was most sensitive for axonal damage in the injured deep cortical layers, cerebellum, and medulla. At 1-2 weeks after injury, APP N-terminus immunostaining mainly showed dot-like axonal profiles in the injured thalamus. APP C-terminus immunoreactivity may serve as an early marker of TAI, and the C-terminal fragments of APP may be involved in the evolution of TAI because C-terminal fragments of APP are neurotoxic and pro-apoptotic. Multiple immunostaining methods may be required to fully recognize the extent of TAI.

Amyloid beta-Protein Precursor↗
PubMed2002

Effects of fluid percussion injury on the neuronal activity in the hippocampal CA1 area and the dentate gyrus of the rat.

The effect of fluid percussion injury (FPI) on the propagation of neuronal activity in the rat hippocampus was investigated by using optical and extracellular recording techniques. Under anesthesia with pentobarbital sodium, a moderate impact (1.5-2.0 atm) was applied to the parietal cerebral cortex of the left hemisphere at -3 mm (i.e. caudal) from bregma, 3.5 mm lateral from the sagittal suture. Systemic oxygenation remained normal during the anesthesia. The rats recovered fully from anesthesia within 30-60 min, and their subsequent behavior, such as feeding and grooming, was normal. After a survival period of 1 week from the FPI or sham-operation, neuronal activities were recorded from the hippocampal CA1 region and the dentate gyrus (DG) in either coronal or horizontal brain slice preparations. In sham-operated rats, there was no significant difference in the neuronal activity between contralateral and ipsilateral hippocampal CA1 areas and DG. In coronal slices (-5.6(-)-6.4 mm from bregma), moderate impact (1.5-2.0 atm) markedly depressed the neuronal activity of the ipsilateral (impact side) CA1 region and of the DG directly under the cerebral cortex that received the impact. In horizontal slices, on the other hand, the neuronal activity was markedly enhanced in the ipsilateral hippocampal CA1 region and the DG adjacent the temporal lobe of the cerebral cortex. Field potentials were recorded from the dentate granule cell layer and the hippocampal CA1 pyramidal cell layer in either coronal or horizontal slice. Moderate impact strongly depressed the field potential in the ipsilateral CA1 region and DG directly under the injured cerebral cortex. In horizontal slices, the field potential was followed by multiple population spikes in ipsilateral hippocampal CA1 and the DG neurons. Bicuculline (15 microM) increased the number of spikes of the field potential even after the brain injury. These results suggest that FPI depresses the neuronal activity in the ipsilateral hippocampus directly under the injured parietal cortex, while it enhances the neuronal activity of the ipsilateral hippocampus adjacent to the temporal cortex. The facilitation of neuronal activity following FPI is not due to disinhibition resulting from depression of GABAergic interneuron activity.

Animals↗
PubMedDate not supplied

Coma associated with flaccidity produced by fluid-percussion concussion in the cat. II: Contribution of activity in the pontine inhibitory system.

In the preceding paper we reported that concussive levels of fluid-percussion head injury can produce transient flaccidity of postural muscles associated with other indices of coma. This reversible coma associated with flaccidity follows an initial period of generalized areflexia and occurs in the absence of EEG slow waves. The present study investigated the physiological mechanisms underlying the flaccidity following concussive head injury be recording dorsal and ventral root potentials of the spinal cord. Studies indicated that, during the initial period of generalized areflexia, afferent input transmission was depressed although the excitability of motoneuronal pools was increased. In contrast, during periods of flaccidity, spinal cord somatomotor functions were depressed while transmission of afferent inputs was recovering. Systematic transection of the brain stem showed that activity within structures lying between collicular and midpontine levels is necessary to produce this latter condition. Cholinergic activation of pontine inhibitory areas within this same region of the rostral pons can produce profound descending inhibitory influences on postural somatomotor function in conjunction with other features of coma including suppression of eye-opening responses. Such effects occur without EEG slow waves. Moreover, other data indicate that local rates of glucose utilization within this pontine inhibitory area increase following concussive head injury. Thus, it is possible that a predominance of activity within the pontine inhibitory area could provide at least one neural basis for the reversible comatose state following concussive head injury characterized by close association between flaccidity and other indices of coma. Possible relationships of these data to clinically observed features of concussion are discussed.

Animals↗
PubMed1979

Percussive injury to peripheral nerve in rats.

Weights were dropped on rat sciatic nerves. Teased fibers and light and electron micrographs of nerves removed between 10 minutes and 2 weeks later were examined. Axonal alterations were seen 10 minutes after injury, and subsequently interruption of axonal continuity with preservation of the basal lamina was apparent. Dissolution of myelin began within 30 minutes and progressed. At 14 days, a segment of some large fibers was devoid of myelin and, by 2 weeks, remyelination had commenced. Demyelination of significant number of fibers was always accompanied by Wallerian degeneration of other fibers of the same nerve. Percussive injury of nerves caused a mixed lesion in which the early and late pathological features were clearly distinguishable from those following crush or compression by a cuff. Any explanation of the transient interruption of function that has been described following such an injury is at present speculative.

Animals↗
PubMed1982

Effects of experimental fluid-percussion injury of the brain on cerebrovascular reactivity of hypoxia and to hypercapnia.

To test the hypothesis that concussive brain injury interferes with the normal vasodilator response of the cerebral circulation to hypoxemia, 30 cats were subjected to mild (PaO2 50 mm Hg) and severe (PaO2 30 mm Hg) hypoxemia while measurements were made of arterial and intracranial pressure, regional cerebral blood flow (CBF), and arterial blood gases. Ten cats served as controls, 10 were subjected to mild fluid-percussion injury of the brain (0.8 to 1.7 atmospheres (atm)), and 10 to severe injury (2.4 to 4.1 atm). The CBF response to hypercapnia (PaCO2 50 mm Hg) was also tested in most animals, and the response of CBF autoregulation to hemorrhagic hypotension was tested in four animals of each group. Trauma was found to severely attenuate the capacity of CBF to increase during hypoxemia. Responsiveness to hypoxemia appeared to be better preserved in traumatized animals than was autoregulation, but was less robust than the response to hypercapnia.

Animals↗
PubMed1995

Loss of forebrain cholinergic neurons following fluid-percussion injury: implications for cognitive impairment in closed head injury.

Disturbances in memory, concentration, and problem solving are common after even mild to moderate traumatic brain injury. Because these functions are mediated in part by forebrain cholinergic and catecholaminergic innervation, in this study the authors sought to determine if experimental concussive injury produces detectable morphological damage to these systems. Fluid-percussion head injury, sufficient to cause a 13- to 14-minute loss of righting reflex, was produced in rats that had been anesthetized with halothane. Injury was delivered either at midline or 2 mm off midline and compared with appropriate sham-injured controls. After 11 to 15 days, the rat brains were stained in serial sections for choline acetyltransferase, tyrosine hydroxylase, dopamine beta-hydroxylase, acetylcholinesterase, and nicotinamide adenine dinucleotide phosphate diaphorase. Cell counts were determined for the entire population of ventrobasal forebrain cholinergic cells. Midline injury produced a bilateral loss of cholinergic neurons averaging 36% in area Ch1 (medial septal nucleus), 45% in Ch2 (nucleus of the diagonal band of Broca), and 41% in Ch4 (nucleus basalis of Meynart), (p < or = 0.05). Lateralized injury resulted in cholinergic neuron loss of similar magnitude ipsilaterally (p < or = 0.05), but a smaller contralateral loss of between 11% and 28%. No loss of neurons was detected in the pontomesencephalic cholinergic groups Ch5 and Ch6. There was no visible effect of head injury on forebrain dopamine or noradrenergic innervation. A significant and apparently selective loss of ventrobasal forebrain cholinergic neurons following brief concussive injury in rats is demonstrated in this study. This type of injury is known to produce significant disturbance in cognitive tasks linked to neocortical and hippocampal cholinergic function. It remains to be determined how this neuron loss occurs, whether it can be prevented with neuroprotective agents, how it affects innervation in target tissues, and whether it occurs in human victims of traumatic brain injury.

Adrenergic Fibers↗