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Suction socket suspension for below-knee amputees.

In this study the current use of suction suspension for below-knee prostheses is examined by means of two questionnaire surveys. The experience of 56 below-knee (B-K) amputees wearing suction socket prostheses is evaluated comparing suction prostheses with previously worn limbs. A high degree of satisfaction was found, with amputees on the whole reporting improved skin condition, diminished pain, and increased activity levels compared to previous prosthetic history. The experience and opinions of 466 certified prosthetist members of the American Orthotist Prosthetist Association are examined in the second survey, including degree of contact, success, and evaluation of problems in using suction suspension for the B-K amputee. This survey indicated limited contact and familiarity with B-K suction suspension, with only 22% stating they had made this type of prosthesis. Prosthetists cited characteristics of the B-K residual limb as the chief deterrent to a successful fitting.

Adult↗

Microdialysis vs. suction blister technique for in vivo sampling of pharmacokinetics in the human dermis.

Our aim was to simultaneously investigate 2 techniques for in vivo sampling of peripheral compartment pharmacokinetics after systemic administration of acetylsalicylic acid. Ten volunteers were given 2 g acetylsalicylic acid orally. Blood samples and dialysates from 4 microdialysis probes inserted in the dermis of the forearm were collected for 5 h and suction blisters were raised 1-3 h after dosing. In microdialysates, both acetylsalicylic acid and the metabolite salicylic acid were measurable in the absence of hydrolysing enzymes. The mean Cmax (maximum concentration) of total, unbound salicylic acid was 9.5 microg/ml in microdialysates, 13.2 microg/ml in suction blister fluid and 56.5 microg/ml in plasma. Mean Tmax (time to Cmax) for salicylic acid was 188 and 161 min in plasma and microdialysates, respectively. The dermis-to-plasma Cmax ratio was 0.16+/-0.04 (mean +/- SD) by microdialysis sampling and 0.25+/-0.09 by the suction blister fluid method. Close correlations (p<0.01) were found between Cmax of salicylic acid in microdialysates and plasma, and between Cmax of salicylic acid in suction blister fluid and plasma. The 2 techniques were in excellent accordance with even closer correlation between maximum concentrations obtained by microdialysis and suction blister fluid sampling (p<0.001). However, comparing the tolerability of the sampling procedure, ease of analysis, and detail in chronology, microdialysis is superior for sampling in vivo pharmacokinetics in the dermis.

Adult↗

Distribution to the skin of penciclovir after oral famciclovir administration in healthy volunteers: comparison of the suction blister technique and cutaneous microdialysis.

Penciclovir is a drug active against herpes simplex viruses located in the epidermis basal layer. The aim of this study was to compare the suction blister technique and microdialysis as methods to measure the penciclovir concentration in the skin after a single dose (250 mg) of its prodrug, famciclovir. Suction blister fluid, microdialysates and plasma were sampled from 11 healthy volunteers for 5 h after famciclovir administration. Both the suction blister technique and microdialysis showed that penciclovir reaches the skin in concentrations sufficient to inhibit herpes virus replication. The maximum concentration in both suction blister fluid and in microdialysate was observed later than in plasma. The microdialysis concentration was decreased by cooling of the skin surface and by adrenaline-mediated vasoconstriction. The microdialysis recovery of penciclovir was studied with respect to the flow-rate of perfusion medium through the microdialysis probe. Microdialysis and the suction blister technique can be used to study the time-concentration profile of penciclovir in the skin and microdialysis allows a continuous sampling of the drug for a prolonged time after administration.

2-Aminopurine↗

The inflammatory response to recycled pericardial suction blood and the influence of cell-saving.

OBJECTIVE: To investigate the inflammatory and cellular response attributed to conventional cardiotomy suction vs cell-saver during cardiac surgery. DESIGN: Thirty-three (n = 33) low-risk patients admitted for routine coronary artery bypass grafting were randomly assigned to two groups: cardiotomy suction or cell-saver for salvage of pericardial blood. The groups were compared with reference to proinflammatory cytokines, complement activation, leukocyte pattern, and haemolysis during and after cardiopulmonary bypass. RESULTS: Pericardial suction blood contained significantly increased concentrations of free plasma haemoglobin, C3a, IL-6, IL-8, TNF-alpha, eosinophils and basophils compared with the systemic circulation. No differences were found for the terminal complement complex and lymphocytes, whereas overall concentrations of leukocytes, platelets and haemoglobin were decreased. Recycling of pericardial suction blood gave no systemic effects except from that of free plasma haemoglobin, which increased significantly. The cell-saver eliminated plasma haemoglobin, but no other effects could be demonstrated. CONCLUSION: Cardiotomy suction is a major cause of haemolysis, but contributes insignificantly to the systemic inflammatory response. Treatment of shed mediastinal blood with a cell-saver reduces haemolysis and may lower the dose load of inflammatory components.

Analysis of Variance↗

Scaling of suction feeding performance in the catfish Clarias gariepinus.

Ontogenetic changes in the absolute dimensions of the cranial system together with changes in kinematics during prey capture can cause differences in the spatiotemporal patterns of water flow generated during suction feeding. Because the velocity of this water flow determines the force that pulls prey toward and into the mouth cavity, this can affect suction feeding performance. In this study, size-related changes in the suction-induced flow patterns are determined. To do so, a mathematical suction model is applied to video recordings of prey capturing Clarias gariepinus ranging in total length from 111 to 923 mm. Although large C. gariepinus could be expected to have increasing peak velocities of water flow compared with small individuals, the results from the hydrodynamic model show that this is not the case. Yet, when C. gariepinus becomes larger, the expansive phase is prolonged, resulting in a longer sustained flow. This flow also reaches farther in front of the mouth almost proportionally with head size. Forward dynamical simulations with spherical prey that are subjected to the calculated water flows indicate that the absolute distance from which a given prey can be sucked into the mouth as well as the maximal prey diameter increase substantially with increasing head size. Consequently, the range of potential prey that can be captured through suction feeding will become broader during growth of C. gariepinus. This appears to be reflected in the natural diet of this species, where both the size and the number of evasive prey increase with increasing predator size.

Animals↗

New technique of seeding chondrocytes into microporous poly(L-lactide-co-epsilon-caprolactone) sponge by cyclic compression force-induced suction.

The initial requirement for a functional engineered cartilage tissue is the effective and reproducible seeding of chondrocytes into the interior of microporous scaffolds. High seeding efficiency, high cell viability, uniform cell distribution, and short operation time are also essential. We devised a new technique of seeding rabbit chondrocytes into microporous poly(L-lactide-co-epsilon-caprolactone) (PLCL) (porosity, 71- 80%; wall thickness, 2 and 6 mm) sponges under compression force-induced suction using a custom designed loading apparatus. Cell distribution and cell viability were determined using confocal laser scanning microscopy with fluorescent dye-staining techniques. Factors that affect the quality of a cell seeded construct were studied, namely, the porosity and thickness of sponges and suction cycles. Under 1 cycle of suction, an increase in porosity promoted cell seeding efficiency (CSE; defined as the percentage of the number of cells in the sponges relative to the initial number of cells seeded), cell viability (at 1 day post seeding), and a relatively uniform cell distribution, whereas thick sponges exhibited an inhomogeneous cell distribution irrespective of incubation time. Multiple cycles of suction of 5 and 10 at 0.1 Hz significantly improved the CSE, whereas high cell viability was maintained and even spatial cell distribution was achieved in 1 week. This study revealed that our newly developed cell seeding technique with multiple cycles of suction is a promising approach to inoculating cells into microporous sponges with high CSE, high cell viability, and homogeneous cell distribution.

Animals↗

Grasp biopsy, suction biopsy, and clinical history in the evaluation of esophagitis in infants 0-6 months of age.

Fifty-three infants 0-6 months of age with abnormal 24-h intraesophageal pH monitoring were evaluated by esophageal suction biopsies and endoscopic grasp biopsies. Histologic esophagitis was present in 30% of the infants. Of the infants with esophagitis, 88% were accurately identified by suction biopsy, and 75% were accurately identified by endoscopic grasp biopsy. Suction biopsy alone was not significantly different from combined grasp and suction biopsy, while differences between grasp biopsy and combined biopsy approached significance (p = 0.051). Twelve clinical symptoms and 21 intraesophageal pH monitoring parameters were evaluated for their ability to predict esophagitis, and none were found to be useful. We conclude that endoscopic esophageal biopsy, while more costly, offers no advantage over suction biopsy for the detection of esophagitis in young infants.

Biopsy↗

The trauma of suction-assisted lipectomy cannula on flap circulation in rats.

The effect of suction-assisted lipectomy on cutaneous blood vessels of inguinal skin flaps was studied and compared in 191 rats. Different types of cannula tips were used; the number of passes was standardized. In one experiment, following suctioning, 3 X 2 cm groin island flaps based on inferior epigastric pedicles were raised and then reattached. Fluorescein dye study and microangiography were performed to evaluate flap viability. Flap survival was determined clinically and by histologic examination on the fifth postoperative day. Three-sided inguinal random-pattern flaps were raised in a second experiment and reattached following suctioning. On the fifth postoperative day, surviving flap areas were measured using standard photographs and an imaging computer and were compared with controls. Results showed that cannula passes accompanied by vacuum are harmful to vessels, while those unaccompanied by vacuum are not. The greater the number of suctioning passes, the more trauma there is to vessels and the greater is the likelihood of flap necrosis. Conical and spatula tips were more harmful to vessels than spherical, cobra, keel cobra, or Fournier tips. These results support the conclusion that suction-assisted lipectomy enhances the possibility of skin necrosis by traumatizing the vascular pedicle of a flap, especially when it is used as an adjunct to flap elevation.

Animals↗

The fate of suctioned and surgically removed fat after reimplantation for soft-tissue augmentation: a volumetric and histologic study in the rabbit.

The use of autologous fat transplantation has seen renewed popularity with the recent advent of liposuction as a body recontouring technique. However, clinicians are still faced with uncertainty concerning the ultimate volume maintenance of the transplanted fat graft at its recipient site. This study was initiated to examine and evaluate the changes in volume of suctioned versus surgically excised fat grafts over a 9-month period in the New Zealand White rabbit. Fat grafts of equal volume were harvested from the groin using standard suction and surgical techniques and transferred into isolated pockets in the ear. Results demonstrate that both suctioned and surgically removed fat grafts undergo significant volume reduction. However, surgically excised fat maintains its volume (42.2 percent; n = 16) better than suction-assisted fat grafts (31.6 percent; n = 16; p < 0.05). Histologic examination showed that fibrous connective tissue was more prevalent in the suctioned fat grafts than in the surgically removed fat grafts.

Adipose Tissue↗

Measurement of the mechanical properties of the skin using the suction test.

INTRODUCTION: The suction test is commonly used to study the mechanical properties of human skin in vivo. The unevenness of the stress fields complicates obtaining the intrinsic mechanical parameters of the skin in vivo because the values of the local stresses and deformations cannot be calculated directly from the displacements and forces applied by the test apparatus. In general, users only take into account the negative pressure applied and the elevation of the dome of skin drawn up in order to deduce the properties of the skin. This method has the major disadvantage of being dependent on the experimental conditions used: in particular, the size of the suction cup and the negative pressure applied. Here, we propose a full mechanical study of the test to provide rigorous results. We compare the frequently used geometric method (making the thin plate hypothesis), Timoshenko's method (which can take greater plate thicknesses into account) and finally various results obtained by the finite elements (FE) technique. METHODS: The suction test was modelled by FE with large displacements and large deformations both for orthotropic and isotropic plates. The results obtained in the elastic domain for various values of Young's modulus and of applied negative pressure were used as references and were compared with methods using analytical relationships. RESULTS: The geometric method generally used in the interpretation of suction tests gives results, which in certain configurations, are very different from those obtained by FE. The method of Timoshenko is suited to thick plates 'in contact' or embedded round the edge, the elevation of the dome and the tension and flexion stresss are analytically accessible through relationships involving four constants that are dependent on the limit conditions. Comparison with the FE results enabled the optimisation of the coefficients to adapt the relationships to the particular conditions of the suction trials. CONCLUSION: We showed the limits of the geometrical method and proposed a solution, which while remaining simple to use, gives results that are closer to reality both for the calculation of the modulus and for the determination of the state of the stresses obtained.

Biomechanical Phenomena↗

The convergent evolution of the pelvic suction cup: A unique key innovation in spiny-finned fishes.

Key innovations open ecological opportunities and can redirect evolutionary trajectories. In spiny-finned fishes, the pelvic suction cup-a fused adhesive structure formed from the pelvic fins and supported by a modified girdle-appears to be one such trait. Using a novel 960-species phylogeny spanning 940 exons and 67 newly sequenced snailfish genomes, we show that the suction cup evolved independently three times across lineages separated by over 100 million years. By enabling adhesion in high-energy habitats such as tide pools and waterfalls, the suction cup set the stage for body depression and accompanying shifts in scales, teeth, and clade-specific ecofunctional profiles. Comparative analyses reveal convergence in a distinctive region of morphospace and body-shape evolution accelerated two- to fivefold. Diversification analyses uncover heterogeneous but elevated rates, with a clear burst in rock-climbing gobies associated with suction cup evolution. By opening novel habitats and fostering phenotypic novelty, the suction cup emerges as a key innovation that reshaped spiny-finned fish evolution.

Animals↗

Low-energy transvenous ablation of the canine atrioventricular conduction system with a suction electrode catheter.

A single suction electrode catheter was used for His bundle electrogram recording. His bundle pacing, and low-energy (20 or 30 J) His bundle ablation in seven dogs. The suction electrode catheter was actively fixed to the atrial endocardium at the His bundle level. Electrophysiologic studies were performed in the control state, immediately after, and late (greater than 40 days) after His bundle ablation and results were correlated with histologic findings in the conduction system. Unipolar His bundle recording and pacing were successfully performed in all dogs with the suction electrode catheter before and after ablation. Complete heart block developed after a single 20 J shock delivered via the suction electrode catheter in all dogs immediately, but reverted to 1:1 atrioventricular conduction with first-degree atrioventricular block in two dogs in which one or two additional shocks (20 or 30 J) produced complete heart block. Mean ablation energy per shock was 22 +/- 4 J. The mean total delivered energy per dog was 31 +/- 20 J. Late electrophysiologic study in all dogs showed persistent complete heart block in five dogs and paroxysmal second-degree or third-degree atrioventricular block in two dogs. Gross examination of the ablation site showed a white plaque above the medial tricuspid leaflet (1.4 to 2.0 cm long and 0.4 to 0.6 cm wide). Microscopically, fibrosis of the penetrating and branching His bundle was seen in all dogs, with minimal atrioventricular node and atrial involvement. Significant proximal right bundle branch fibrosis was observed in the two dogs receiving one or two additional shocks. We conclude that the suction electrode catheter permits repeated His bundle recording, pacing, and ablation with a single catheter. Permanent and safe low-energy ablation of the canine His bundle is feasible. Focal injury localized to the target area in the conduction system can be obtained.

Animals↗

Evidence of a dominant backward-propagating "suction" wave responsible for diastolic coronary filling in humans, attenuated in left ventricular hypertrophy.

BACKGROUND: Coronary blood flow peaks in diastole when aortic blood pressure has fallen. Current models fail to completely explain this phenomenon. We present a new approach-using wave intensity analysis-to explain this phenomenon in normal subjects and to evaluate the effects of left ventricular hypertrophy (LVH). METHOD AND RESULTS: We measured simultaneous pressure and Doppler velocity with intracoronary wires in the left main stem, left anterior descending, and circumflex arteries of 20 subjects after a normal coronary arteriogram. Wave intensity analysis was used to identify and quantify individual pressure and velocity waves within the coronary artery circulation. A consistent pattern of 6 predominating waves was identified. Ninety-four percent of wave energy, accelerating blood forward along the coronary artery, came from 2 waves: first a pushing wave caused by left ventricular ejection-the dominant forward-traveling pushing wave; and later a suction wave caused by relief of myocardial microcirculatory compression-the dominant backward-traveling suction wave. The dominant backward-traveling suction wave (18.2+/-13.7 x 10(3) W m(-2)s(-1), 30%) was larger than the dominant forward-traveling pushing wave (14.3+/-17.6 x 10(3) W m(-2) s(-1), 22.3%, P =0.001) and was associated with a substantially larger increment in coronary blood flow velocity (0.51 versus 0.14 m/s, P <0.001). In LVH, the dominant backward-traveling suction wave percentage was significantly decreased (33.1% versus 26.9%, P =0.01) and inversely correlated with left ventricular septal wall thickness (r =-0.52, P <0.02). CONCLUSIONS: Six waves predominantly drive human coronary blood flow. Coronary flow peaks in diastole because of the dominance of a "suction" wave generated by myocardial microcirculatory decompression. This is significantly reduced in LVH.

Adult↗

Scaling of suction-feeding kinematics and dynamics in the African catfish, Clarias gariepinus.

Scaling effects on the kinematics of suction feeding in fish remain poorly understood, at least partly because of the inconsistency of the results of the existing experimental studies. Suction feeding is mechanically distinct from most other type of movements in that negative pressure inside the buccal cavity is thought to be the most important speed-limiting factor during suction. However, how buccal pressure changes with size and how this influences the speed of buccal expansion is unknown. In this paper, the effects of changes in body size on kinematics of suction feeding are studied in the catfish Clarias gariepinus. Video recordings of prey-capturing C. gariepinus ranging in total length from 111 to 923 mm were made, from which maximal displacements, velocities and accelerations of several elements of the cranial system were determined. By modelling the observed expanding head of C. gariepinus as a series of expanding hollow elliptical cylinders, buccal pressure and power requirement for the expansive phase of prey capture were calculated for an ontogenetic sequence of catfish. We found that angular velocities decrease approximately proportional with increasing cranial size, while linear velocities remain more or less constant. Although a decreasing (angular) speed of buccal expansion with increasing size could be predicted (based on calculations of power requirement and the expected mass-proportional scaling of available muscular power in C. gariepinus), the observed drop in (angular) speed during growth exceeds these predictions. The calculated muscle-mass-specific power output decreases significantly with size, suggesting a relatively lower suction effort in the larger catfish compared with the smaller catfish.

Africa↗

Suction patterns in preterm infants.

The suction pattern for breast and bottle feeding in two groups of preterm infants is described. The time elapsed between birth and the moment of suction was longer in preterm neonates born at lower gestational ages for both groups studied, breast and bottle fed (figure 1). The evolution of suckling in breastfeeding was analyzed in a composite study (longitudinal and transverse) in a group of 16 neonates starting from 32 weeks of gestation. The velocity of milk extraction during suckling varied with gestational age. It was uniform at lower gestational ages, then it became faster in the first minutes and at the 36th week, it was very similar to that of mature neonates (figure 2 and table I). The evaluation of bottle feeding was performed in a transverse study in 46 preterm neonates which had been exclusively bottle fed during 1 or 2 weeks. All of them had previously been fed using an orogastric tube. Nourishing time was shorter than in breastfeeding; the average duration was 3.7 minutes (table II). The greatest volume was ingested in the first minute, 40% (range between 44 and 25%) (figure 3). The frequency of suction did not change the duration of feeding, but it was found that the efficiency of suction (number of suctions to ingest 1 cc) was significantly lower in the first minute (Anova, p < 0.05) (figure 4).

Bottle Feeding↗

Electromyographic study of muscular activity in the amputation stump while walking with PTB- and PTB-suction prosthesis.

A comparative electromyographic study of the muscular activity while waling with PTB and PTB-suction prosthesis is presented. The PTB-suction prosthesis has been used clinically since 1969 with generally promising results. This prosthesis is mainly of value for patients with skin problems (poor sensibility and contact sores) and also has a cosmetic advantage. The present investigation has demonstrated that there is frequently a muscular activity pattern when walking with the PTB-suction prosthesis which is similar to that of a normal leg. The PTB prosthesis often shows a pattern of simultaneous contractions of antagonistic muscles. Furthermore, when the EMG-pattern is more "normal" and the amplitude higher with the PTB-suction prosthesis, it is probably the more suitable prosthesis. These EMG investigations can thus be a possible adjunct in the selection between the PTB-suction prosthesis and PTB prosthesis.

Adaptation, Physiological↗

[Meta-analysis on the effectiveness of interventions applied to preventing endotracheal suction-induced hypoxemia].

PURPOSE: This study was conducted to investigate the effects of the suction-induced hypoxemia interventions. METHOD: 30 suction-induced hypoxemia interventions were reviewed for the purpose of meta-analysis. RESULT: The study showed that both preoxygenation and insufflation were the most frequently examined oxygenation time periods, and hyperoxygenation combined with hyperinflation was the most commonly applied oxygenation method in order to prevent suction-induced hypoxemia. The greatest effect was obtained by providing oxygenation before and after suctioning, whereas negative effect(the contrary results from the study hypotheses) was frequently obtained by applying insufflation only. Applying hyperoxygenation combined with hyperinflation had the greatest effect over that of applying hyperoxygenation only, even though the difference between effect sizes of both methods were statistically significant. CONCLUSION: The results of meta-analysis showed that the occurrence rate of hypoxemia after suctioning was significantly reduced with the overall interventions for hypoxemia (decreasing 40% of occurrence rate), independent with time periods or methods for providing oxygenation.

English Abstract↗

[Effects of a closed endotracheal suction system on oxygen saturation, ventilator-associated pneumonia, and nursing efficacy].

PURPOSE: The purpose of this study was to examine the effects of a closed endotracheal suction system(CES) on oxygen saturation, ventilator associated pneumonia(VAP), and nursing efficacy in mechanically ventilated patients. METHOD: This study was conducted in the intensive care unit of a University Hospital in Gwangju City. Data was collected from July to October, 2003. Seventy mechanically ventilated patients were randomly divided into two groups; 32 for CES and 38 for open endotracheal suction system(OES) protocol. Twenty one nurses were also involved to examine the nurses' attitude of usefulness about CES. RESULT: SaO(2) was significantly different between CES and OES. The incidence of VAP in CES was lower than that of OES. Nursing efficacy was related to time, cost, and usefulness of the suction system. Time of suctioning in CES was shorter than that of OES. CES also contributed significantly to lower the cost of treatment than OES. The usefulness score of CES increased after 6 months of use. CONCLUSION: CES prevented VAP, was cost effective, and a safe suctioning system. CES ncan be used with patients with sensitivity to hypoxygenation and with a high risk of VAP.

Adult↗