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PubMed2006

An experimental animal model of spinal root compression syndrome: an analysis of morphological changes of myelinated axons during compression radiculopathy and after decompression.

The treatment of radicular pain is mainly empirical because there are only few experimental studies dealing with morphological changes during compression radiculopathy. The goal of the study was to investigate changes in the morphology of myelinated axons during spinal root compression and the influence of decompression in a new rat model. The number of myelinated axons and their diameter were measured at 1, 2, 5, and 8 weeks during compression of the dorsal spinal root. The same approach was applied for 1-week compression followed by decompression for 1 or 2 weeks and compression for 5 weeks followed by 3-week decompression. A decrease in the number of myelinated axons (particularly those of large diameters) occurred after compression for 1 week. Continued compression for up to 8 weeks resulted in centripetal increase in the number of myelinated axons and the persistence of a small fraction of large myelinated axons at the site of compression. After that time, a decreased number of axons and a reduced fraction of large myelinated axons occurred again. Decompression after 1-week compression caused a rapid increase in the number of both small and large myelinated axons within the spinal root including the site of compression. A small fraction of regenerated axons was found after 5-week compression followed by 3-week decompression. Finally, we investigated the time course of the temporary increase in the number of regenerated myelinated axons during dorsal root compression for up to 8 weeks. The efficacy of decompression was superior when applied one week after compression or after regress of the acute phase of aseptic inflammation associated with fragility of spinal root. The results of the study verify the need for early surgical decompression to prevent irreversible damage of the spinal roots.

Animals↗

PubMed2006

The impact of image information on compressibility and degradation in medical image compression.

The aim of the study was to demonstrate and critically discuss the influence of image information on compressibility and image degradation. The influence of image information on image compression was demonstrated on the axial computed tomography images of a head. The standard Joint Photographic Expert Group (JPEG) and JPEG 2000 compression methods were used in compression ratio (CR) and in quality factor (QF) compression modes. Image information was estimated by calculating image entropy, while the effects of image compression were evaluated quantitatively, by file size reduction and by local and global mean square error (MSE), and qualitatively, by visual perception of distortion in high and low contrast test patterns. In QF compression mode, a strong correlation between image entropy and file size was found for JPEG (r=0.87, p < 0.001) and JPEG 2000 (r=0.84, p < 0.001), while corresponding local MSE was constant (4.54) or nearly constant (2.36-2.37), respectively. For JPEG 2000 CR compression mode, CR was nearly constant (1:25), while local MSE varied considerably (2.26 and 10.09). The obtained qualitative and quantitative results clearly demonstrate that image degradation highly depends on image information, which indicates that the degree of image degradation cannot be guaranteed in CR but only in QF compression mode. CR is therefore not a measure of choice for expressing the degree of image degradation in medical image compression. Moreover, even when using QF compression modes, objective evaluation, and comparison of the compression methods within and between studies is often not possible due to the lack of standardization of compression quality scales.

Algorithms↗

PubMed2006

Quality of lay person CPR performance with compression: ventilation ratios 15:2, 30:2 or continuous chest compressions without ventilations on manikins.

The new CPR guidelines emphasise chest compression depth and have increased the compression:ventilation ratio to cause less time intervals without chest compressions. How this change may influence the quality of chest compressions is not documented. Sixty-eight volunteers among travellers at Oslo international airport and a senior citizen centre performed 5 min of CPR on a manikin with compression:ventilation ratios 15:2, 30:2 or continuous chest compressions. Median age was 37.5 years (range 15-87), 59% were men, and 71% reported CPR training median 8 years (3-15) previously. Three of 22, 4 of 23 and 3 of 23 subjects in the 15:2, 30:2 and continuous compressions groups respectively stopped before 5 min had passed. Mean compression depth was 41 +/- 11, 45 +/- 8 and 30 +/- 8 mm, respectively. Depth was reduced as a function of time in the continuous compression group. Number of compressions per minute was 40 +/- 9, 43 +/- 14 and 73 +/- 24 and percent no flow time 49 +/- 13%, 38 +/- 20% and 1 +/- 2%, respectively. In conclusion, continuous chest compressions without ventilations gave significantly more chest compressions per minute, but with decreased compression quality. No flow time for 30:2 was significantly less than for 15:2.

Adolescent↗

PubMed1994

Effect of compression ratio in a slow-acting compression hearing aid: paired-comparison judgments of quality.

Paired-comparison judgments of quality were obtained from 20 hearing-impaired listeners (half with a small dynamic range and half with a large dynamic range) for speech-in-noise (vent, apartment, and cafeteria) processed through a slow-acting compression hearing aid. Compression ratio was varied (1, 1.5, 2, 3, 5, and 10:1). Compression threshold, attack time, and release time were fixed. Sound quality judgments were significantly affected by compression ratio, noise, and dynamic range. Preference decreased with increasing compression ratio. The selection of compression ratio. The selection of compression ratios < or = 2:1 was significantly higher than of compression ratios > 3:1. Less compression (no compression or 1.5:1) was preferred with the highest level noise (cafeteria noise) than with the lower level noises (vent or apartment). In particular, the small dynamic range group preferred compression with the vent and apartment noises (noise below the compression threshold), but preferred a linear hearing aid with the cafeteria noise (above the compression threshold). The large dynamic range group showed a slightly greater preference for the linear hearing aid for all three noises.

Adolescent↗

PubMed2002

[Manual compression versus mechanical compression device (FemoStop) after diagnostic coronary angiography with/without intervention].

BACKGROUND: The aim of our study was to evaluate the practicability and the complication rates of two different forms of the post-angiographic closure of the femoral artery. METHODS: We randomized 239 patients over a time period of 4 months to either a mechanical compression system (FemoStop, 111 patients) or to conventional manual compression (128 patients). A Doppler-sonographic examination was performed if the patient reported pain of the puncture site, or if auscultation or palpation suspected a complication on the day after compression. RESULTS: After manual compression, Doppler-sonography had to be performed in 21 patients (16.4%). In the FemoStop-group only 14 patients (12.6%, p = ns) had to be referred for ultrasound examination. A complication was detected in 13 patients (10.1%) after manual compression and in 5 patients (4.5%, p = ns) after closure with the mechanical device. The incidence of a pseudo-aneurysma or of an arterio-venous fistula did not show any difference between the two groups. In 6 patients of the manual compression group a hematoma was found (p < 0.05), whereas no hematoma occurred in the FemoStop-group. None of the hematomas required the infusion of blood concentrates or surgical correction. In one patient with extreme overweight the mechanical compression device could not be applied. The mechanical compression device was used successfully in patients who had received heparin, acetyl-salicyl-acid or a glycoprotein IIb/IIIa receptor antagonist and in whom a significantly longer compression time and higher complication rate could have been expected. In addition, post-angiographic closure with the was less time consuming for the staff involved. In contrast, the higher cost of the mechanical compression device presents a disadvantage. CONCLUSION: A mechanical compression device (FemoStop) can be used successfully in routine post-angiographic management and shows a trend to lower complication rates than manual compression and increased acceptance by patients and physicians. However, the overall costs are higher for the mechanical compression device.

Age Factors↗

PubMed2006

JPEG2000 compression of thin-section CT images of the lung: effect of compression ratio on image quality.

PURPOSE: To assess retrospectively the effect of the Joint Photographic Experts Group 2000 (JPEG2000) compression ratio on the quality of thin-section computed tomographic (CT) images. MATERIALS AND METHODS: In this institutional review board-approved investigation (protocol 238/2004), thin-section CT images were subjected to irreversible JPEG2000 compression by using five compression ratios (3:1, 5:1, 7:1, 9:1, and 11:1). Three radiologists independently evaluated 60 thin-section CT images, of various diseases, that were obtained with single-detector (weighted dose index, 14.4 mGy) and multidetector (weighted dose index, 9.8 mGy) CT. Toggling between the original and compressed images, readers had to identify the original image by using a forced-choice two-alternative model and to subjectively rank the quality of what they believed to be the compressed image. To assess the reader's ability to distinguish the compressed from the original image, a binomial test was used. Bonferroni correction was applied for all multiple tests. RESULTS: Images compressed with a ratio of 3:1 were not distinguishable from original images (P > .2 for all readers). With use of the 5:1 ratio, minor differences in appearance between the compressed and original images were seen by one of the three readers. With use of higher compression ratios (>/=7:1), all readers (P < .001) recognized the original image. The quality of more than 90% of the images compressed with a 7:1 or higher ratio was substantially degraded. Single-detector and multidetector CT results were not significantly different. CONCLUSION: The highest ratio that yielded visually lossless compression of thin-section CT images was 3:1. With the 5:1 ratio, there was minor image quality loss, while use of higher compression ratios (>/=7:1) caused substantial degradation of image quality and potential loss of diagnostic information.

Adult↗

PubMed2000

An analysis of the efficacy of bag-valve-mask ventilation and chest compression during different compression-ventilation ratios in manikin-simulated paediatric resuscitation.

The ideal chest compression and ventilation ratio for children during performance of cardiopulmonary resuscitation (CPR) has not been determined. The efficacy of chest compression and ventilation during compression ventilation ratios of 5:1, 10:2 and 15:2 was examined. Eighteen nurses, working in pairs, were instructed to provide chest compression and bag-valve-mask ventilation for 1 min with each ratio in random on a child-sized manikin. The subjects had been previously taught paediatric CPR within the last 3 or 5 months. The efficacy of ventilation was assessed by measurement of the expired tidal volume and the number of breaths provided. The rate of chest compression was guided by a metronome set at 100/min. The efficacy of chest compressions was assessed by measurement of the rate and depth of compression. There was no significant difference in the mean tidal volume or the percentage of effective chest compressions delivered for each compression-ventilation ratio. The number of breaths delivered was greatest with the ratio of 5:1. The percentage of effective chest compressions was equal with all three methods but the number of effective chest compressions was greatest with a ratio of 5:1. This study supports the use of a compression-ventilation ratio of 5:1 during two-rescuer paediatric cardiopulmonary resuscitation.

Cardiopulmonary Resuscitation↗

PubMed2002

Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis.

OBJECTIVE: We evaluated the usefulness of graded compression sonography with the adjuvant use of a posterior manual compression technique for detection of the vermiform appendix and the diagnosis of acute appendicitis. SUBJECTS AND METHODS: Five hundred seventy consecutive patients referred for suspected acute appendicitis were prospectively examined by original, graded compression sonography with a 5- or a 7.5-MHz linear transducer. A posterior manual compression technique was added for 85 patients whose vermiform appendix was not identified with graded compression sonography. For consensus, another experienced radiologist or a resident observer was in attendance throughout the examination. The detection rate for the vermiform appendix and the diagnostic accuracy for acute appendicitis before and after the adjuvant use of a posterior manual compression technique were obtained, respectively, and final diagnoses were established with the official radiology reports, surgical results, and clinical follow-up. RESULTS: Graded compression sonography enabled visualization of the vermiform appendix in 485 (85%) of 570 patients. After the adjuvant use of a posterior manual compression technique, the vermiform appendix was found in an additional 57 of 85 patients, with the number of identified vermiform appendices increasing to 542 (95%) of 570 patients. The 57 patients with an additionally found appendix included 11 patients with acute appendicitis. The sonographic diagnosis of acute appendicitis was determined in 312 of 542 patients. Acute appendicitis was proven by surgery in 311 of 332 patients. Sonography was used to establish the diagnosis in 302 of the 311 patients with proven appendicitis; there were 10 false-positive diagnoses and nine false-negative diagnoses. One false-positive diagnosis was acquired after use of the posterior manual compression technique. These results showed more improvement than those of the probabilities for acute appendicitis with single use of graded compression sonography. CONCLUSION: Graded compression sonography with adjuvant use of a posterior manual compression technique seems to be useful for detecting the vermiform appendix and for diagnosing acute appendicitis.

Acute Disease↗

PubMed1992

A study of chest compression rates during cardiopulmonary resuscitation in humans. The importance of rate-directed chest compressions.

A prospective, cross-over trial was performed comparing two different rates of precordial compression using end-tidal carbon dioxide as an indicator of the efficacy of cardiopulmonary resuscitation in 23 adult patients. A second purpose of this study was to determine the effect of audio-prompted, rate-directed chest compressions on the end-tidal carbon dioxide concentrations during cardiopulmonary resuscitation. Patients with cardiac arrest received external chest compressions, initially in the usual fashion without rate direction and then with rhythmic audiotones for rate direction at either 80 compressions per minute or 120 compressions per minute. Nineteen of 23 patients had higher end-tidal carbon dioxide levels at the compression rate of 120 per minute. The mean end-tidal carbon dioxide level during compressions of 120 per minute was 15.0 +/- 1.8 mm Hg, slightly but significantly higher than the mean level of 13.0 +/- 1.8 mm Hg at a compression rate of 80 per minute. However, end-tidal carbon dioxide levels increased rather dramatically when audiotones were used to guide the rate of chest compressions. Mean end-tidal carbon dioxide concentration was 8.7 +/- 1.2 mm Hg during standard cardiopulmonary resuscitation immediately before audio-prompted, rate-directed chest compression and increased to 14.0 +/- 1.3 mm Hg after the first 60 seconds of audible tones directing compressions. Using end-tidal carbon dioxide as an indicator of cardiopulmonary resuscitation efficacy, we conclude that audible rate guidance during chest compressions may improve cardiopulmonary resuscitation performance.

Aged↗

PubMed1995

A model for acute, chronic, and delayed graded compression of the dog cauda equina. Neurophysiologic and histologic changes induced by acute, graded compression.

STUDY DESIGN: The results of acute compression on nerve function and morphology were analyzed in a recently developed model for graded cauda equina compression in the dog. OBJECTIVES: The model was developed to better mimic the clinical situation of cauda equina compression in association with spinal canal stenosis. SUMMARY OF BACKGROUND DATA: The compression of the cauda equina has been induced by metal clips, plastic bands, constrictors, and inflatable balloons. No model has used the intact spinal canal and induced compression by increasing the pressure per se in the canal. METHODS: An inflatable balloon with a diameter exceeding the diameter of the spinal canal was placed under the lamina of the L7 vertebra in the dog. The balloon was inflated to various pressures, and muscle action potential area and nerve conduction velocity were monitored during 2 hours of compression and 1.5 hours of recovery. Nerve root specimens were processed for light microscopic examination. RESULTS: There was a progressive reduction of muscle action potential area and nerve conduction velocity that was proportional to the applied pressure. Histologic evaluation revealed no nerve fiber damage but a slight intraneural edema after compression at 200 mg Hg. CONCLUSIONS: The presented model may provide reproducible results regarding neurophysiologic and morphologic effects after acute, graded compression of the dog cauda equina. Two additional conclusions can be made from this study. First, the area measurement of the MAP is probably well suited for recordings and analyses of changes in muscle action potentials. Second, the specific onset rate of this study, in relation to previous studies, indicates that there is a threshold for the compression onset rate for inducing additional nerve injury located in the interval 0.1-0.8 seconds. The results from the present study provides important baseline data for the continued studies on chronic and intermittent compression with the compression model.

Action Potentials↗

PubMed1984

Compressibility and constitutive equation of arterial wall in radial compression experiments.

A large number of papers treat the tensile properties of arterial wall, but few treat compressive properties. Almost everybody assumes incompressibility; few have measured the vessel wall fluid extrusion due to compressive loading. In this work, uniaxial compressive force is applied directly on rabbit thoracic artery in the radial direction to study its constitutive equation under compressive stresses. The resulting stress-strain curves show that the wall material becomes increasingly stiffer at larger compressive strain, quite similar to the behavior in tension. A pseudo-strain energy function of the exponential type which has been applied successfully on the tension side is used to identify the material constants on the compression side. The material constants are identified in two ways: with and without the assumption of incompressibility. To determine the compressibility of the wall, the fluid extrusion accompanying this type of loading is measured, and is found to be in the range of 0.50-1.26% of the undeformed tissue volume per 10 kPa compressive stress loading in the radial direction. At compressive stresses higher than 30 kPa, the percentage of fluid extrusion per unit compressive stress decreases. At this degree of fluid extrusion the tissue is only slightly compressible (or nearly incompressible). However, the use of incompressibility assumption in the stress-strain relationship results in a set of material constants which is very different from that derived without that assumption.

Animals↗

PubMed1999

Clinical benefits of lightweight compression: reduction of venous-related symptoms by ready-to-wear lightweight gradient compression hosiery.

BACKGROUND: Medical-grade compression of class I (20-30 mmHg) and class II (30-40 mmHg) have been shown to be beneficial against venous hypertension or congestion. Relatively few studies address the effects of ready-to-wear (RTW) lightweight gradient compression pantyhose on venous symptoms. OBJECTIVE: To perform a study comparing the effects of two different compression RTW lightweight gradient compression stockings (8-15 mmHg and 15-20 mmHg) on the venous symptoms of flight attendants. METHOD: A prospective crossover trial of symptom evaluation in 19 flight attendants was performed in which participants rated their symptoms on a visual analog scale. During the initial phase, participants wore no compression for 2 weeks. They then wore 8-15 mmHg and 15-20 mmHg gradient compression support hose while flying over a 4-week period. Symptoms before and after wearing the gradient compression stockings were compared and statistically analyzed. RESULTS: Wearing of 8-15 mmHg gradient hose resulted in statistically significant improvement of discomfort (P < 0.01). Swelling, fatigue, aching, and tightness of the leg were all improved to a statistically significant degree (P < 0.01). For 15-20 mmHg gradient hosiery, symptoms were improved to a statistically significant or almost significant level. The difference between the 8-15 mmHg and 15-20 mmHg compression was not statistically significant. CONCLUSIONS: Use of lightweight (low compression) RTW gradient compression hosiery is very effective in improving symptoms of discomfort (P < 0.01), swelling (almost P < 0. 05), fatigue (P < 0.05), aching (P < 0.01), as well as leg tightness. Improvement of symptoms is statistically significant compared to no compression when hosiery was worn regularly during waking hours for 4 weeks.

Adult↗

PubMed1998

The effects of lag-time and dwell-time on the compaction properties of 1:1 paracetamol/microcrystalline cellulose tablets prepared by pre-compression and main compression.

The effects of lag-time and dwell-time on the compaction properties of tablets compressed from a 1:1 blend of paracetamol and microcrystalline cellulose have been examined using a compaction simulator. Increases in lag-times (from 0.06 to 0.53 s) resulted in small increases in the tensile strengths of the tablets when combinations of 80 and 160 MPa were used as the compression pressures. Further increases in lag-time did not alter the tablet strengths. When combinations of 240 and 320 MPa were used for pre-compression and main compression, the effects on the tensile strengths were more complex, partly because the high elastic recoveries of the tablets resulted in greater variability in the data. Increases in lag-times from 0.06 to 0.97 s resulted in an increase of between 12 and 28% in tensile strength. Longer lag-times (1.24 or 1.52 s) did not result in further increases in tensile strength. The application of a dwell-time of 0.26 s during pre-compression or main compression pressures of 80 and 160 MPa generally led to a decrease (14-22%) in tensile strength compared with tablets where no dwell-time was used. This was because of increases in both the elastic recoveries and elastic energies. Subsequent increases in dwell-time from 0.26 to 0.9 s resulted in increases in tablet strength compared with that obtained when no dwell-time was applied. The tensile strengths of tablets made with a pre-compression of 160 MPa then a main compression of 80 MPa were 11-33% higher than those of tablets made with a pre-compression of 80 MPa then a main compression of 160 MPa. This was because higher plastic energies and more plastic deformation occurred at the higher pre-compression. Generally, the application of dwell-time resulted in greater increases in tensile strengths than lag-time, which had less effect on the compaction properties.

Acetaminophen↗

PubMedDate not supplied

Image compression in morphometry studies requiring 21 CFR Part 11 compliance: procedure is key with TIFFs and various JPEG compression strengths.

This study aims to compare the integrity and reproducibility of measurements created from uncompressed and compressed digital images in order to implement compliance with 21 CFR Part 11 for image analysis studies executed using 21 CFR Part 58 compliant capture systems. Images of a 400-mesh electron microscope grid and H&E stained rat liver tissue were captured on an upright microscope with digital camera using commercially available analysis software. Digital images were stored as either uncompressed TIFFs or in one of five different levels of JPEG compression. The grid images were analyzed with automatic detection of bright objects while the liver images were segmented using color cube-based morphometry techniques, respectively, using commercially-available image analysis software. When comparing the feature-extracted measurements from the TIFF uncompressed to the JPEG compressed images, the data suggest that JPEG compression does not alter the accuracy or reliability to reproduce individual data point measurements in all but the highest compression levels. There is, however, discordance if the initial measure was obtained with a TIFF format and subsequently saved as one of the JPEG levels, suggesting that the use of compression must precede feature extraction. It is a common practice in software packages to work with TIFF uncompressed images. However, this study suggests that the use of JPEG compression as part of the analysis work flow was an acceptable practice for these images and features. Investigators applying image file compression to other organ images will need to validate the utility of image compression in their work flow. A procedure to digitally acquire and JPEG compress images prior to image analysis has the potential to reduce file archiving demands without compromising reproducibility of data.

Animals↗

PubMed1992

Effects of compression on physiologic integrity of the spinal cord, on circulation, and clinical status in four different directions of compression: posterior, anterior, circumferential, and lateral.

The authors investigated the effects of focal compression on physiologic integrity; somatosensory evoked potentials, neurogenic motor evoked potentials and spine-to-spine potentials, on spinal cord circulation and clinical status in four different type of compression; posterior, anterior, circumferential, and lateral in 31 pigs. Spine-to-spine potentials degraded earlier in amplitude than somatosensory evoked and motor evoked potentials regardless of direction of compression. The first lost potential was the somatosensory evoked one during posterior, circumferential, and lateral compression and motor evoked potentials during anterior compression. Somatosensory evoked potential was the only wave to detect the side of lateral compression. Following release of compression somatosensory evoked potentials and motor evoked potentials returned almost to 100% in amplitude, whereas spine-to-spine potentials recovered to approximately 50%. At that time all animals showed grossly normal motion in hind-limb, therefore spine-to-spine potentials might be too sensitive to motor function. Spine-to-spine potentials should contain more tracts than either somatosensory evoked potentials or motor evoked potentials. Somatosensory evoked potentials probably show more posterior part, whereas motor evoked potentials do more of the anterior part of the spinal cord. The spinal cord revealed a complete ischemia regardless of direction of compression when at least one potential was gone, however it regained the shape and perfusion following release of compression although there were some hemorrhagic contusions remaining. These suggest that ischemic changes may play some part in degradation of potentials, however it does not influence much the recovery following release of compression because it regains quickly. The final recovery depends on the complication.

Animals↗

PubMed2006

Compressive strength and compressive fatigue limit of conventional and high viscosity posterior resin composites.

The purpose of this study was to compare the compressive strengths and compressive fatigue limits of three posterior composite resins (Filtek P-60, Surefil and Prodigy Condensable) and a universal restorative composite (Z-100). Cylindrical specimens (8 mm in length x 4 mm in diameter) were used. The dynamic test was performed using the staircase method, and the ratio between compressive fatigue limit and compressive resistance was also calculated (n = 15). The compressive strength and compressive fatigue limit data were analyzed by Anova and Tukeys test. The Z-100 composite demonstrated higher compression strength (307.20 MPa) than Surefil (266.93 MPa) and Prodigy Condensable (222.08 MPa). The resistance of Filtek P-60 (270.44 MPa) was similar to the resistances of Z-100 and Surefil, while Prodigy Condensable presented the lowest compressive strength. In the compressive fatigue limit tests, Filtek P-60 demonstrated a higher value (184.20 MPa) than Prodigy Condensable (155.50 MPa). Surefil (165.74 MPa) and Z-100 (161.22 MPa) presented limits similar to those of Filtek P-60 and Prodigy Condensable. The compressive fatigue limit/compressive strength ratio was 70.01% for Prodigy Condensable, 68.11% for Filtek P-60, 62.09% for Surefil and 52.48% for Z-100. It was concluded that the Z-100 universal composite was more sensitive to the dynamic test than the high viscosity materials.

Composite Resins↗

PubMed1977

Plastic flow during compression of directly compressible fillers and its effect on tablet strength.

The effects of the duration of the overall compression cycle and of the duration of the maximum compressive force on tablet strength were studied using an instrumented rotary tablet press. Various direct compression fillers were evaluated. Increasing the overall compression cycle duration to 10 sec resulted in significantly greater tablet tensile strengths with microcrystalline cellulose and compressible starch fillers but not with lactose or compressible sugar. Increasing the duration of the maximum compressive force to 20 sec significantly increased the tensile strength in all cases, but microcrystalline cellulose and compressible starch tablets were affected more than lactose or sugar tablets. The maximum compressive force decayed with time for all fillers but at a greater rate with microcrystalline cellulose and compressible starch. This behavior was attributed to differences in the extent of plastic flow. The decay curves were analyzed using the Maxwell model.

Calcium Phosphates↗

PubMed2003

Effect of calf-thigh intermittent pneumatic compression device after total hip arthroplasty: comparative analysis with plantar compression on the effectiveness of reducing thrombogenesis and leg swelling.

The purpose of this study was to evaluate the efficacy of two intermittent pneumatic compression devices as prophylaxis against intravascular coagulation and leg swelling following total hip arthroplasty. We studied 121 patients by assessing thrombogenesis using the D-dimer level before and after total hip arthroplasty. In addition, the patients' postoperative swelling was evaluated by measuring the thigh and lower leg circumference. Altogether, 58 patients were assigned to the calf-thigh pneumatic compression group, and the other 63 were assigned to the plantar compression group; the two pneumatic compression devices were compared to evaluate which was more effective for reducing thrombogenesis. At 7 days postoperatively, the mean D-dimer levels of the calf-thigh compression group and the plantar compression group were 8.86 and 9.26 microg/ml, respectively. There was no significant difference ( P = 0.697) between the two groups. However, the increased ratio of the circumference of the thigh, which was compared after arthroplasty, averaged 1.22% in the calf-thigh compression group and 3.19% in the plantar compression group, which was significantly different ( P << 0.01). Calf-thigh pneumatic compression was found to be more effective than plantar compression for reducing thigh swelling during the early postoperative stage.

Adult↗