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PubMed1997

New device for compression of the radial artery after diagnostic and interventional cardiac procedures.

Recently the transradial route has emerged as a valuable alternative to the femoral approach for coronary angiography and angioplasty. However, sheath and catheter size and their immediate removal after the procedure, combined with aggressive antiplatelet and anticoagulant therapies, have favored mechanical compression of the radial artery to achieve satisfactory hemostasis. We report on our initial clinical experience with a new device specially designed for prolonged controlled mechanical compression of the radial artery (the RadiStop radial compression system, RADI Medical Systems AB, Uppsala, Sweden). A total of 159 consecutive patients (mean age 60 +/- 11 yr, 130 males) who required either coronary angiography (group 1, 103 patients) or ad hoc or elective coronary angioplasty (group 2, 56 patients) via the right radial route had local hemostasis with the RadiStop system. In group 1, 4F and 5F sheaths and catheters were used, whereas in group 2, 6F systems were inserted in the radial artery. Hemostasis was achieved with the device in all patients but was considered difficult to obtain in 4 patients (2.5%). Twenty-eight patients (18%) considered the device uncomfortable or painful, but no release of pressure was necessary. The mean compression time was 151 +/- 82 min (114 +/- 64 min in group 1, and 223 +/- 64 min in group 2; P = 0.0001). There were 23 local complications (15%). In 7 patients (4.4%), the radial pulse was absent after compression and at discharge, without major clinical consequences. In one patient, recurrent bleeding occurred 2 hr after compression, requiring a new compression session. In 15 patients, a small local hematoma was observed. Neither heparin dosage nor the use of a 6F sheath affected the rate of radial artery patency in this survey. We conclude that the use of this device for mechanical compression of the radial artery after coronary angiography and angioplasty is efficient, and that its use is related to an acceptable rate of local complications.

Aged↗

PubMed1999

A prospective, randomized evaluation of nonsurgical closure of femoral pseudoaneurysm by compression device with or without ultrasound guidance.

Femoral artery pseudoaneurysm (PA) is a significant complication following diagnostic or therapeutic catheterization. The treatment of choice for femoral artery PA is freehand ultrasound-guided compression repair (UGCR). An alternative method is compression by mechanical devices. The study evaluated the mechanical compression device (FemoStop) with (G1) or without (G2) ultrasound guidance for initial placement in a randomized fashion. Thirty-eight patients (20 women, 18 men) age 40 to 85 (mean 54) years with clinical signs of PA underwent diagnostic color Doppler ultrasound. Randomization yielded 19 patients each for G1 and G2. PA occurred after 12 diagnostic cardiac catheterizations, 18 coronary stent implantations or balloon angioplasties, 2 electrophysiology procedures, and 6 peripheral percutaneous transluminal angioplasties. The G1 protocol was successful in 15 of 19 patients (79%), with a mean compression time of 28 min. The three other patients were treated successfully with UGCR. Only one patient needed vascular surgery. The G2 protocol was successful in 14 of 19 patients (74%) with a mean compression time of 33 min. The failed patients were treated successfully: three with UGCR and two with the same mechanical compression device now positioned under ultrasound control. Compression therapy with the compression device (FemoStop) for iatrogenic femoral pseudoaneurysm does not require ultrasound guidance for positioning. Cathet. Cardiovasc. Intervent. 47:304-309, 1999.

Aged↗

PubMedDate not supplied

Evaluation of posterior cerebral artery blood flow with transcranial Doppler sonography: value and risk of common carotid artery compression.

PURPOSE: Investigations of the posterior cerebral arteries (PCA) by transcranial Doppler sonography (TCD) may be less reliable than investigations of the anterior part of the circle of Willis. Nevertheless, a true PCA may be identified by manual compression of the proximal common carotid artery (CCA) during TCD. Therefore, we used CCA compression in clinically indicated TCD studies and assessed retrospectively its risks and prospectively its benefits for PCA evaluations. METHODS: Using the transtemporal approach, we prospectively assessed flow velocities in posteriorly located blood vessels in 180 consecutive patients before and during CCA compression. The complications of CCA compression were retrospectively reviewed in all 3,383 clinical TCD investigations performed over an 8-year period. RESULTS: Decreased flow velocities during ipsilateral CCA compression occurred in 17% of patients. A PCA-like vessel with perfusion from the carotid artery or PCA supply from the carotid circulation was unmasked. Mixed distal PCA support by the posterior communicating artery and proximal PCA could not be shown by TCD. Transient cerebral symptoms occurred in less than 0.4% of the 3,383 retrospectively reviewed TCD investigations; no other adverse effects were seen. CONCLUSIONS: TCD without CCA compression may lead to false identification of the PCA. Since transient cerebral symptoms during CCA compression are rare, CCA compression can be used when a clinical TCD investigation of intracranial collateral blood flow compensation is indicated or when the identification of a cerebral artery is uncertain.

Blood Flow Velocity↗

PubMed2003

Compression therapy for treating stage I and II (Widmer) post-thrombotic syndrome.

BACKGROUND: Post-thrombotic syndrome (PTS) is a long-term complication of deep vein thrombosis characterised by chronic complaints, swelling, and skin changes in the affected limb. One in every three patients with deep vein thrombosis develops post-thrombotic complications within five years. OBJECTIVES: To assess the effectiveness of compression therapy in patients with stage I and II post-thrombotic syndrome according to the classification of Widmer. Interventions of interest included elastic compression stockings and mechanical devices, compared with no intervention and with each other. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Specialised Trials Register (last searched April 2003), and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 1, 2003). In addition, journals, conference proceedings and bibliographies were hand searched. Personal contact with other investigators involved in the clinical area was sought to get information about missed or unpublished studies. SELECTION CRITERIA: Trials that evaluated compression therapy for stage I and II (Widmer) post-thrombotic syndrome. Primary outcomes were leg ulceration, or deterioration of post-thrombotic syndrome. There were no restrictions on date or language. One reviewer (DNK) assessed titles and abstracts for relevance. This was verified independently by a second reviewer (MWCS). DATA COLLECTION AND ANALYSIS: Details of eligible studies were extracted and summarised using data extraction sheets. Data extraction was undertaken by one reviewer (DNK) and verified by a second reviewer (MHP). MAIN RESULTS: Only two trials were identified that addressed physical treatment of post-thrombotic syndrome. Both trials were initiated by the same group of investigators. A cross-over study lasting two months compared low and high pressure with intermittent compression units for severe post-thrombotic syndrome. This showed a beneficial effect of higher pressures. The second study, in patients with mild to moderate post-thrombotic symptoms, showed no effect of elastic compression stockings (30-40 mm Hg at the ankle region) when compared to 'placebo' stockings that were one to two sizes too large. REVIEWER'S CONCLUSIONS: There is some evidence of a beneficial effect of intermittent pneumatic compression units, but the study was too small and of too short a duration to draw strong conclusions. Further research is needed in order to assess whether intermittent pneumatic compression units give long term reduction and relief of the symptoms caused by post-thrombotic syndrome, and prevent deterioration and leg ulceration. The use of elastic compression stockings to treat post-thrombotic syndrome cannot be supported on the basis of the currently available data.

Bandages↗

PubMed1994

Differences in osteonal micromorphology between tensile and compressive cortices of a bending skeletal system: indications of potential strain-specific differences in bone microstructure.

BACKGROUND: It has been hypothesized that bone has the capacity to accommodate regional differences in tension and compression strain mode and/or magnitude by altering its osteonal microstructure. We examined a simple cantilevered bone to determine whether regional differences in particular strain-related features are reflected in the microstructural organization of compact bone. METHODS & RESULTS: The artiodactyl (e.g., sheep and deer) calcaneus has a predominant loading condition which is typified by prevailing compressive and tensile strains on opposite cortices, and variations in strain magnitudes across each of these cortices. Microscopic examination showed osteon density and cortical porosity differences between tension (caudal) and compression (cranial) cortices, averaging 11.4% more osteons in the compression cortex (P < 0.01) and 80.2% greater porosity in the tension cortex (P < 0.01). There is 43.5% more interstitial bone in the compression cortex (P < 0.01). Osteons in the compression cortex also have smaller areas in contrast to the larger area per osteon in the tension cortex. Although no definite transcortical gradient in osteonal density or cortical porosity is found, fractional area of interstitial bone is larger and osteon population density is lowest in the endocortical regions of both tension and compression cortices. The endocortical regions also have greater porosity than their corresponding middle and pericortical regions (P < 0.01). CONCLUSIONS: These osteonal microstructure and cortical porosity differences may be adaptations related to regional differences in strain mode and/or strain magnitude. This may be related to the disparity in mechanical properties of compact bone in tension vs. compression. These differences may reflect a capacity of bone to process local and regional strain-related information.

Adaptation, Physiological↗

PubMed2007

Interruption of blood flow during compression and radial artery occlusion after transradial catheterization.

OBJECTIVES: To analyze the possible relationship between compression after transradial catheterization and radial artery occlusion. BACKGROUND: Radial artery occlusion is an important concern of transradial catheterization. Interruption of radial artery flow during compression might influence the rate of radial artery occlusion at follow-up. METHODS: A prospective study including 275 consecutive patients undergoing transradial catheterization was conducted. Arterial sheaths were removed immediately after procedures and conventional compressive dressings were left in place for 2 hr. The pulse oximeter signal in the index finger during ipsilateral ulnar compression was used for the assessment of radial artery flow. RESULTS: Radial artery flow was absent in 174 cases (62%) immediately after entry-site compression. After 2 hr of conventional hemostasis, radial artery flow was absent in 162 cases (58%) before bandage removal. At 7-day follow-up, 12 patients (4.4%) had absent pulsations and radial artery flow was absent in 29 cases (10.5%). Patients with an occluded radial artery at follow-up had significantly smaller arterial diameters at baseline (2.23+/-0.4 mm vs. 2.40+/-0.5 mm; P=0.032) and more frequently had absent flow during hemostasis (90% vs. 54%, P<0.001). Stepwise logistic regression analysis revealed that absent flow before compressive bandages removal was the only independent predictor of radial artery occlusion at follow-up (OR=6.7; IC 95%: 1.95-22.9; P=0.002). CONCLUSIONS: Flow-limiting compression is a frequent finding during conventional hemostasis after transradial catheterization. Absence of radial artery flow during compression represents a strong predictor of radial artery occlusion.

Aged↗

PubMed1995

Time-dependent changes in the response of cartilage to static compression suggest interstitial pH is not the only signaling mechanism.

The goal of the present study was to reexamine the role of interstitial pH in regulating the biosynthetic rate in cartilage tissue by addressing two research questions: (a) Do small, short-term changes in interstitial pH, induced independently by two different mechanisms (namely, by controlling the pH of the medium or by mechanical compression), result in biosynthetic rates commensurate with those expected from the "natural" relationship between interstitial pH and biosynthesis? and (b) Are the effects of changes in the pH of the medium or in compression the same for short-term (14-hour) and long-term (60-hour) exposures? Biosynthetic rates were estimated from incorporation of sulfate and proline into explants of bovine epiphyseal cartilage during the final 14 hours of culture. These rates decreased with decreasing pH of the medium, with increasing compression, and with decreasing native glycosaminoglycan content; or, expressed in terms of interstitial pH, acidification induced by compression or by lowering the pH of the medium resulted in a decreased biosynthetic rate, whereas interstitial acidification effected by increasing glycosaminoglycan content enhanced it. When the time for which tissue was exposed to changes in the pH of the medium was increased from 14 to 60 hours, the relationship between the biosynthetic rate and the pH remained constant whereas the relationship between the biosynthetic rate and compression was reversed. These data suggest that the transduction mechanisms underlying the response to pH of the medium and compression differ and that some adaptation or stimulation by modest levels of compression can occur with longer exposures. Interstitial pH is not the sole determinant of biosynthesis, and it cannot really account for the long-term response of cartilage tissue to static compression.

Analysis of Variance↗

PubMed1996

Comparison of functional deficits in the rabbit tibialis anterior following tourniquet ischemia and tourniquet compression.

The purpose of this study was to measure the contractile properties of skeletal muscle after direct compression with a tourniquet and to compare these properties with those found after a similar period of tourniquet ischemia. A rabbit model of tourniquet compression of the tibialis anterior was developed and tested for this investigation. Fifty-seven animals then were divided into four protocol groups: (a) thigh tourniquet (ischemia) at 350 mm Hg (46.7 kPa), (b) leg tourniquet (compression) at 350 mm Hg (46.7 kPa), (c) leg tourniquet at 125 mm Hg (16.7 kPa), and (d) controls. A significant decrease in maximum tetanic tension was demonstrated in all three experimental groups. Direct compression at 350 mm Hg resulted in the greatest decline in maximum tetanic tension (22.6% of control), followed by compression at 125 mm Hg (30.5%) and ischemic injury (40.2%). In addition, direct compression at 350 mm Hg resulted in a significantly greater loss of force-generating capacity when compared with the ischemic group (p < 0.01). A similar pattern was noted for the rate of rise in maximum tetanic tension. Gross histologic examination of the tibialis anterior sections was consistent with the results of functional testing, with the more severe abnormalities noted in the compressed specimens. These results clearly demonstrate that tourniquet compression injury results in a more significant loss of functional strength and contractile speed than tourniquet ischemia. Further investigations on the safe limits of tourniquet use thus should be directed toward measuring the effect of the pneumatic tourniquet on the underlying soft tissues.

Animals↗

PubMed2000

Effect of compressive loading on chondrocyte differentiation in agarose cultures of chick limb-bud cells.

It is well established that mechanical loading is important to homeostasis of cartilage tissue, and growing evidence suggests that it influences cartilage differentiation as well. Whereas the effect of mechanical forces on chondrocyte biosynthesis and gene expression has been vigorously investigated, the effect of the mechanical environment on chondrocyte differentiation has received little attention. The long-term objective of this research is to investigate the regulatory role of mechanical loading in cell differentiation. The goal of this study was to determine if mechanical compression could modulate chondrocyte differentiation in vitro. Stage 23/24 chick limb-bud cells, embedded in agarose gel, were subjected to either static (constant 4.5-kPa stress) or cyclic (9.0-kPa peak stress at 0.33 Hz) loading in unconfined compression during the initial phase of commitment to a phenotypic lineage. Compared with nonloaded controls, cyclic compressive loading roughly doubled the number of cartilage nodules and the amount of sulfate incorporation on day 8, whereas static compression had little effect on these two measures. Neither compression protocol significantly affected overall cell viability or the proliferation of cells within nodules. Since limb-bud mesenchymal cells were seeded directly into agarose, an assessment of cartilage nodules in the agarose reflects the proportion of the original cells that had given rise to chondrocytes. Thus, the results indicate that about twice as many mesenchymal cells were induced to enter the chondrogenic pathway by cyclic mechanical compression. The coincidence of the increase in sulfate incorporation and nodule density indicates that the primary effect of mechanical compression on mesenchymal cells was on cellular differentiation and not on their subsequent metabolism. Further studies are needed to identify the primary chondrogenic signal associated with cyclic compressive loading and to determine the mechanism by which it influences commitment to or progression through the chondrogenic lineage, or both.

Animals↗

PubMedDate not supplied

Video on the Internet: An introduction to the digital encoding, compression, and transmission of moving image data.

In this paper, we seek to provide an introduction to the fast-moving field of digital video on the Internet, from the viewpoint of the biological microscopist who might wish to store or access videos, for instance in image databases such as the BioImage Database (http://www.bioimage.org). We describe and evaluate the principal methods used for encoding and compressing moving image data for digital storage and transmission over the Internet, which involve compromises between compression efficiency and retention of image fidelity, and describe the existing alternate software technologies for downloading or streaming compressed digitized videos using a Web browser. We report the results of experiments on video microscopy recordings and three-dimensional confocal animations of biological specimens to evaluate the compression efficiencies of the principal video compression-decompression algorithms (codecs) and to document the artefacts associated with each of them. Because MPEG-1 gives very high compression while yet retaining reasonable image quality, these studies lead us to recommend that video databases should store both a high-resolution original version of each video, ideally either uncompressed or losslessly compressed, and a separate edited and highly compressed MPEG-1 preview version that can be rapidly downloaded for interactive viewing by the database user.

Algorithms↗

PubMed1984

The relationship between ATP hydrolysis and active force in compressed and swollen skinned muscle fibers of the rabbit.

We investigated whether the inhibition of force generation observed in compressed muscle fibers is accompanied by a coupled reduction in hydrolytic activity. Isometric force and rates of ATP hydrolysis (ATPase) were measured as functions of the relative width of chemically skinned skeletal muscle fiber segments immersed in relaxing (pCa greater than 8) and activating (pCa 4.9) salt solutions. Osmotic radial compression of the fiber segment was produced (with little or no affect on striation spacing) by adding Dextran T500 to the bathing media. ADP as a product of ATP hydrolysis in fibers undergoing 10-15 min contractions was measured using high pressure liquid chromatography. Compression of the (initially swollen) fiber segment with dextran produced a slight (4%) increase in average active force and then, with further compression, a sharp decrease (with maximum around in situ width). With compression, the average ATPase of the fiber decreased monotonically, and with extreme compression (with 0.22 g dextran per ml), ATPase fell to a fifth of its level determined in dextran-free solution while force was abolished. The time course of active force development was described by the sum of two exponential functions, the faster of which characterized the rate of rise. Fiber compression (0.14 g dextran per ml) reduced the rate of rise of force ten-fold compared to that in dextran-free solution. Hindrance of cross movement is proposed to account for the inhibition of active force generation and (coupled) ATPase in compressed fibers.

Adenosine Triphosphatases↗

PubMed1994

The electroretinogram during orbital compression following intraorbital regional block for cataract surgery.

The electroretinogram (ERG) is a transient biopotential that reflects the electrical response of the distal retina to photostimulation. Disturbances in retinal circulation produce characteristic abnormalities in the ERG wave form. The objective of this study was to investigate the changes in the ERG produced by combined retrobulbar and peribulbar injections of a large volume (8 ml) of local anaesthetic, followed by ocular compression. Electroretinogram recordings were obtained from skin electrodes placed on the infero orbital ridge in response to stroboscopic flash stimulation in 34 adult patients undergoing cataract surgery: (a) prior to regional anaesthesia (baseline condition); (b) within one minute after regional anaesthesia of the orbit (block condition); (c) after ten minutes of orbital compression with a Honan's device at 30 mmHg. (compression condition); (d) and five minutes after removal of orbital compression (recovery condition). The ERG implicit times of both a- and b-wave increased (P < 0.001) after anaesthetic block. The amplitude of the a- and b-waves also decreased (P < 0.001) immediately following anaesthetic block and continued to decrease following application of the compression device (P < 0.01). Following removal of ocular compression the amplitude of the b-wave increased (P < 0.01). Only the a-wave implicit time (P < 0.005) decreased with release of ocular compression. These findings are compatible with the ERG changes of transient retinal ischaemia produced by ocular compression.

Adult↗

PubMed1991

Image data compression using a new floating-point digital signal processor.

A new dual-ported, floating-point, digital signal processor has been evaluated for compressing 512 and 1,024 digital radiographic images using a full-frame, two-dimensional, discrete cosine transform (2D-DCT). The floating point digital signal processor operates at 49.5 million floating point instructions per second (MFLOPS). The level of compression can be changed by varying four parameters in the lossy compression algorithm. Throughput times were measured for both 2D-DCT compression and decompression. For a 1,024 x 1,024 x 10-bit image with a compression ratio of 316:1, the throughput was 75.73 seconds (compression plus decompression throughput). For a digital fluorography 1,024 x 1,024 x 8-bit image and a compression ratio of 26:1, the total throughput time was 63.23 seconds. For a computed tomography image of 512 x 512 x 12 bits and a compression ratio of 10:1 the throughput time was 19.65 seconds.

Algorithms↗

PubMed1996

Clinical evaluation of irreversible data compression for computed radiography in excretory urography.

Efficient data compression is required for practical daily use of digital images in computed radiography (CR). This study investigated the clinical utility of data compression in excretory urography using the FCR 9000 system (Fuji Photo Film, Tokyo, Japan). Type III data compression technique was used, which can achieve a 20:1 to 25:1 compression ratio. To evaluate the degradation of image quality, we compared paired original and compressed CR images. Although a slight deterioration of image quality was noted in the renal calyx including collecting tubules among various anatomical structures, the difference was not significant. Receiver operating characteristics analysis revealed no significant difference among the original and compressed images. We conclude that compressed CR images using Type III data compression technique in excretory urography appear to be clinically applicable and acceptable.

Adolescent↗

PubMed2003

Visually lossless threshold determination for microcalcification detection in wavelet compressed mammograms.

The aim of this study was to determine the visually lossless threshold of a wavelet-based compression algorithm in case of microcalcification cluster detection in mammography. The threshold was determined by means of observer performance using a set of digitized mammograms. In addition, the transfer characteristics of the compression algorithm were assessed by means of image-quality parameters using computer-generated test images. The observer performance study was based on rating performed by four independent radiologists, who reviewed 68 mammograms, from the Digital Database for Screening Mammography (DDSM), at six different compression ratios. Receiver operating characteristics (ROC) analysis was performed on observers' responses and the area under ROC curve (A(z)) was calculated at each compression ratio for each observer. The parameters used for assessment of transfer characteristics of the compression algorithm were input/output response, noise, high-contrast response, and low-contrast-detail response. The computer-generated test image, used for this assessment, mimicked mammographic image characteristics (pixel size, pixel depth, and noise) as well as microcalcification characteristics (size and contrast). The ROC analysis for microcalcification cluster detection indicated a threshold at compression ratio 40:1, as Student's t-test shows statistically significant differences in A(z) values (p<0.05) for compression ratios 70:1 and 100:1. Observers' grading of mammogram quality lowers this threshold at 25:1. Low-contrast-detail detectability in the transfer characteristics study indicate a threshold of 35:1, whereas non-perceptibility of image-quality-parameters degradation lowers this threshold to 30:1. The ROC and transfer characteristics analysis provided comparable thresholds, indicating the potential use of the latter in limiting the target range of compression ratios for subsequent observer studies.

Aged↗

PubMed2006

A biophysical model of the inner hair cell: the contribution of potassium currents to peripheral auditory compression.

The term peripheral auditory compression refers to the fact that the whole range of audible sound pressure levels is mapped into a narrower range of auditory nerve responses. Peripheral compression is the by-product of independent compressive processes occurring at the level of the basilar membrane, the inner hair cell (IHC), and the auditory nerve synapse. Here, an electrical-circuit equivalent of an IHC is used to look into the compression contributed by the IHC. The model includes a mechanically driven transducer potassium (K(+)) conductance and two time- and voltage-dependent basolateral K(+) conductances: one with fast and one with slow kinetics. Special attention is paid to faithfully implement the activation kinetics of these basolateral conductances. Optimum model parameters are provided to account for previously reported in vitro observations that demonstrate the compression associated with the gating of the transducer and of the basolateral channels. Without having to readjust its parameters, the model also accounts for the in vivo nonlinear IHC transfer characteristics. Model simulations are then used to investigate the relative contribution of the transducer and basolateral K(+) currents to the nonlinear IHC input/output functions in vivo. The simulations suggest that the voltage-dependent activation of the basolateral currents compresses the DC potential for stereocilia displacements above approximately 5 nm. The degree of compression exceeds 2-to-1 and is similar for all stimulation frequencies. The AC potential is compressed in a similar way, but only for frequencies below 800 Hz. The simulations further suggest that the nonlinear gating of the transducer current is responsible for the expansive growth of the DC potential with increasing sound level (slope of 2 dB/dB) at low sound pressure levels.

Animals↗

PubMed2002

The effects of irreversible JPEG compression on an automated algorithm for measuring carotid artery intima-media thickness from ultrasound images.

Our ultrasound practice has begun to investigate automated measurements of carotid artery intima-media thickness (IMT) as an indicator of subtle atherosclerosis. Since our clinical ultrasound images are irreversibly compressed, we investigated the effects of this compression on our IMT measurements. We obtained 10 ultrasound images of normal carotid arteries. These were compressed using JPEG to ratios of 5:1, 10:1, 15:1, 20:1, and 30:1. IMT measurements made from all compressed and uncompressed images were compared. For compression ratios ?10:1, IMT deviations between compressed and uncompressed images were ?0.03 mm. Higher than 10:1, the overall IMT deviations were small (0.01 +/- 0.04 mm), although one 25% deviation was measured. Comparison of other parameters yielded similar results. This initial study indicates that compression at 10:1 using baseline JPEG should have little effect on IMT measurements made using the current algorithm, and that compression to 20:1 or 30:1 may be feasible.

Algorithms↗

PubMed1992

Active compression-decompression resuscitation: a novel method of cardiopulmonary resuscitation.

Chest compression is an important part of cardiopulmonary resuscitation (CPR), but it only aids circulation during a portion of the compression cycle and has been shown to only minimally increase blood flow to vital organs. The purpose of this study was to quantitate the short-term hemodynamic effects of CPR with a hand-held suction device that incorporates both active compression and decompression of the chest. The suction device was applied to the middle of the sternum and compared with standard manual CPR in eight nonventilated anesthetized dogs. Coronary perfusion pressure, systolic and diastolic aortic pressures, right atrial diastolic pressure, and the velocity time integral (an analog of cardiac output), which were obtained by means of transesophageal pulsed wave Doppler echocardiography from the main pulmonary artery, were measured every 30 seconds during CPR. Minute ventilation was measured over the last minute of each CPR technique. Both active compression-decompression CPR and standard CPR were sequentially performed for 2 minutes in random order 30 seconds after induced ventricular fibrillation. The CPR techniques consisted of 100 compressions per minute, with a compression depth of 1.5 to 2 inches and a 50% duty cycle. Coronary perfusion pressure, velocity time integral (cardiac output analog), minute ventilation, and systolic arterial pressure were all significantly improved by active compression-decompression CPR when compared with standard CPR. We conclude that active compression-decompression CPR is a simple technique that appears to improve coronary perfusion pressure, systolic arterial pressure, cardiac output, and minute ventilation in nonventilated animals when compared with standard CPR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗