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PubMed2000

Alterations in the determinants of diastolic suction during pacing tachycardia.

In cardiomyocytes, generation of restoring forces (RFs) responsible for elastic recoil involves deformation of the sarcomeric protein titin in conjunction with shortening below slack length. At the left ventricular (LV) level, recoil and filling by suction require contraction to an end-systolic volume (ESV) below equilibrium volume (Veq) as well as large-scale deformations, for example, torsion or twist. Little is known about RFs and suction in the failing ventricle. We undertook a comparison of determinants of suction in open-chest dogs previously subjected to 2 weeks of pacing tachycardia (PT) and controls. To assess the ability of the LV to contract below Veq, we used a servomotor to clamp left atrial pressure and produce nonfilling diastoles, allowing measurement of fully relaxed pressure at varying volumes. We quantified twist with sonomicrometry. We also assessed transmural ratios of N2B to N2BA titin isoforms and total titin to myosin heavy chain (MHC) protein. In PT, the LV did not contract below Veq, even with marked reduction of volume (end-diastolic pressure [EDP], 1 to 2 mm Hg), whereas in controls ESV was less than Veq when EDP was less than approximately 5 mm Hg. In PT, both systolic twist and diastolic untwisting rate were reduced, and there was exaggerated transmural variation in titin isoform and titin-to-MHC ratios, consistent with the more extensible N2BA being present in larger amounts in the subendocardium. Thus, in PT, determinants of suction at the level of the LV are markedly impaired. The altered transmural titin isoform gradient is consistent with a decrease in RFs and may contribute to these findings.

Animals↗

PubMed2005

A noninvasive method for assessing impaired diastolic suction in patients with dilated cardiomyopathy.

BACKGROUND: Diastolic suction is a major determinant of early left ventricular filling in animal experiments. However, suction remains incompletely characterized in the clinical setting. METHODS AND RESULTS: First, we validated a method for measuring the spatio-temporal distributions of diastolic intraventricular pressure gradients and differences (DIVPDs) by digital processing color Doppler M-mode recordings. In 4 pigs, the error of peak DIVPD was 0.0+/-0.2 mm Hg (intraclass correlation coefficient, 0.95) compared with micromanometry. Forty patients with dilated cardiomyopathy (DCM) and 20 healthy volunteers were studied at baseline and during dobutamine infusion. A positive DIVPD (toward the apex) originated during isovolumic relaxation, reaching its peak shortly after mitral valve opening. Peak DIVPD was less than half in patients with DCM than in control subjects (1.2+/-0.6 versus 2.5+/-0.8 mm Hg, P<0.001). Dobutamine increased DIVPD in control subjects by 44% (P<0.001) but only by 23% in patients with DCM (P=NS). DIVPDs were the consequence of 2 opposite forces: a driving force caused by local acceleration, and a reversed (opposed to filling) convective force that lowered the total DIVPD by more than one third. In turn, local acceleration correlated with E-wave velocity and ejection fraction, whereas convective deceleration correlated with E-wave velocity and ventriculo:annular disproportion. Convective deceleration was highest among patients showing a restrictive filling pattern. CONCLUSIONS: Patients with DCM show an abnormally low diastolic suction and a blunted capacity to recruit suction with stress. By raising the ventriculo:annular disproportion, chamber remodeling proportionally increases convective deceleration and adversely affects left ventricular filling. These previously unreported mechanisms of diastolic dysfunction can be studied by using Doppler echocardiography.

Adult↗

PubMed2004

Muscle activation and strain during suction feeding in the largemouth bass Micropterus salmoides.

Activation and strain in the sternohyoideus (SH) were measured in vivo in five largemouth bass Micropterus salmoides. The SH is thought to actuate lower jaw depression, hyoid depression and suspensorial abduction during suction feeding in teleost fish. Sonomicrometry was used to measure fascicle shortening and lower jaw kinematics, while activity was measured by electromyography (EMG). SH fascicles shortened by an average of 11% during suction feeding. In three fish SH fascicles consistently shortened during fast lower jaw depression, but in two individuals they contracted isometrically or lengthened slightly during fast lower jaw depression. The SH continued shortening after peak gape, presumably actuating hyoid depression and lateral expansion of the buccal cavity. Onset of SH relengthening and onset of lower jaw elevation were simultaneous, as were the return of the SH to resting length and gape closure. Activation followed the onset of shortening by an average of 23 ms, although the muscle was active an average of 15 ms before the onset of rapid shortening. SH fascicles reached sustained shortening velocities averaging -2.5 fascicle lengths per second, and generally increased shortening velocity after peak gape. The shortening velocities measured in this study suggest that the SH actively shortens to generate power during suction feeding. This study is the first direct measurement of in vivo muscle function during suction feeding, the most common mechanism of prey capture among aquatic vertebrates.

Animals↗

PubMed2005

Sucking while swimming: evaluating the effects of ram speed on suction generation in bluegill sunfish Lepomis macrochirus using digital particle image velocimetry.

It is well established that suction feeding fish use a variable amount of swimming (ram) during prey capture. However, the fluid mechanical effects of ram on suction feeding are not well established. In this study we quantified the effects of ram on the maximum fluid speed of the water entering the mouth during feeding as well as the spatial patterns of flow entering the mouth of suction-feeding bluegill sunfish Lepomis macrochirus. Using Digital Particle Image Velocimetry (DPIV) and high-speed video, we observed the flow in front of the mouth of three fish using a vertical laser sheet positioned on the mid-sagittal plane of the fish. From this we quantified the maximum fluid speed (measured at a distance in front of the mouth equal to one half of the maximum mouth diameter), the degree of focusing of water flow entering the mouth, and the shape of the ingested volume of water. Ram speed in 41 feeding sequences, measured at the time of maximum gape, ranged between 0 and 25 cm s(-1), and the ratio of ram speed to fluid speed ranged from 0.1% to 19.1%. In a regression ram speed did not significantly affect peak fluid speed, but with an increase in ram speed the degree of focusing of water entering the mouth increased significantly, and the shape of the ingested volume of water became more elongate and narrow. The implications of these findings are that (1) suction feeders that employ ram of between 0% and 20% of fluid speed sacrifice little in terms of the fluid speeds they generate and (2) ram speed enhances the total body closing speed of the predator.

Animals↗

PubMed2005

Spatial and temporal patterns of water flow generated by suction-feeding bluegill sunfish Lepomis macrochirus resolved by Particle Image Velocimetry.

The suction-feeding fish generates a flow field external to its head in order to draw prey into the mouth. To date there are very few empirical measurements that characterize the fluid mechanics of suction feeding, particularly the temporal and spatial patterns of water velocity in front of the fish. To characterize the flow in front of suction-feeding bluegill sunfish Lepomis macrochirus, measurements with high spatial (<1 mm) and temporal (500 Hz) resolution were taken using Particle Image Velocimetry (PIV). In an analysis separate from the PIV, high-speed video sequences were used for a novel method of visually tracking every seed particle for the duration of each feeding in order to determine directly the total parcel of water that the fish ingests. PIV measurements and particle tracking show that water is drawn from all around the mouth. Fluid velocity decreases rapidly with distance from the mouth and is only significant (>5% of speed at the mouth) within roughly 1 mouth diameter of the fish. Suction feeders gain little in terms of extending this flow field by even substantial increases in the fluid speed at the mouth opening. Instead, the chief advantage of increased flow speed at the mouth may be the increased magnitude of generated forces within the space very close to the mouth. After scaling of the velocity field based on size of the mouth opening and the measured fluid speed at a fixed position, the measured velocity profiles for all feedings are very similar to one another, so that a functional relationship for the magnitude of fluid speed as a function of distance from the predator mouth is presented and shown to be accurate over the range of kinematic variables tested. This relationship describes the velocity field both along the centerline of the fish and along transects lying at an angle to the centerline within both the mid-sagittal and frontal planes. Comparison of the time-resolved fluid velocity measurements to gape kinematics demonstrate that peak fluid speed occurs simultaneously with 95% of peak gape, showing that the bluegill maximizes nearly simultaneously both the generated forces and size of the region over which these forces act. The magnitude of peak fluid speed during each strike decreases as a function of increasing time to peak gape (r2 = 0.87), demonstrating a strong relationship between the rate of buccal cavity expansion and maximum generated flow speed.

Animals↗

PubMed2006

The pressures of suction feeding: the relation between buccal pressure and induced fluid speed in centrarchid fishes.

Suction feeding fish rapidly expand their oral cavity, resulting in a flow of water directed towards the mouth that is accompanied by a drop in pressure inside the buccal cavity. Pressure inside the mouth and fluid speed external to the mouth are understood to be mechanically linked but the relationship between them has never been empirically determined in any suction feeder. We present the first simultaneous measurements of fluid speed and buccal pressure during suction feeding in fishes. Digital particle image velocimetry (DPIV) and high-speed video were used to measure the maximum fluid speed in front of the mouth of four largemouth bass and three bluegill sunfish by positioning a vertical laser sheet on the mid-sagittal plane of the fish. Peak magnitude of pressure inside the buccal cavity was quantified using a transducer positioned within a catheter that opened into the dorsal wall of the buccal cavity. In both species the time of peak pressure preceded the time of peak fluid speed by as much as 42 ms, indicating a role for unsteady flow effects in shaping this relation. We parameterized an existing model of suction feeding to determine whether the relationship between peak pressures and fluid speeds that we observed could be predicted using just a few kinematic variables. The model predicted much higher fluid speeds than we measured at all values of peak pressure and gave a scaling exponent between them (0.51) that was higher than observed (0.36 for largemouth bass, 0.38 for bluegill). The scaling between peak buccal pressure and peak fluid speed at the mouth aperture differed in the two species, supporting the recent conclusion that species morphology affects this relation such that a general pattern may not hold.

Animals↗

PubMed2001

Evaluating the use of ram and suction during prey capture by cichlid fishes.

We characterized prey-capture strategies in seven species of cichlid fishes representing diverse trophic habits and anticipated feeding abilities. The species examined were Petenia splendida, Cichla ocellaris, Cichlasoma minckleyi, Astronotus ocellatus, Crenicichla geayi, Heros severus (formerly Cichlasoma severum) and Cyprichromis leptosoma. Three individuals per species were filmed with video at 500 Hz as they captured live adult Artemia sp. and Poecilia reticulata. For each feeding sequence, we measured the contribution of predator movement towards the prey (i.e. ram) and the movement of prey towards the predator due to suction. The use of ram differed significantly among prey types and predator species, varying as much as sixfold across predator species. High values of ram resulted in high attack velocities. Jaw protrusion contributed as much as 50% to overall ram values in some species, verifying its role in enhancing attack velocity. Suction distance did not vary significantly among species. Diversity in prey-capture behavior was therefore found to reflect differences among species in the strategy used to approach prey. Limited variation in the distance from which prey were sucked into the mouth is interpreted as the result of an expected exponential decline in water velocity with distance from the mouth of the suction-feeding predator. We propose that this relationship represents a major constraint on the distance over which suction feeding is effective for all aquatic-feeding predators.

Animals↗

PubMed1976

Comparison of tracheobronchial suction catheters in humans. Visualization by fiberoptic bronchoscopy.

Tracheobronchial suctioning was performed in 20 patients undergoing diagnostic or therapeutic bronchoscopic examination. The effect of a single suctioning procedure on the airway mucosa was observed and recorded by still and cine photography through a fiberoptic bronchoscope. A variety of catheters of various designs were evaluated. All produced a negligible amount of trauma, and none was superior in efficiently evacuating mucus from the airways. Mucosal trauma with tracheobronchial suctioning procedures is more likely due to repetition, vigor, and amount of suction applied, regardless of which type of catheter is used.

Bronchi↗

PubMed1999

Comparison of rebiopsy rates after stereotactic core needle biopsy of the breast with 11-gauge vacuum suction probe versus 14-gauge needle and automatic gun.

OBJECTIVE: The 11-gauge vacuum suction probe is an alternative to the 14-gauge needle and automatic gun for performing stereotactic core needle biopsies. This study compares rebiopsy rates after stereotactic core needle biopsies that were performed with the two methods. The study also assesses the outcomes of those repeat biopsies. MATERIALS AND METHODS: Five hundred ninety-two stereotactic core needle biopsies using a 14-gauge needle and automatic gun and 354 using an 11-gauge vacuum suction probe were performed consecutively. Excluding malignancies, the number of cases requiring rebiopsy and the reasons for rebiopsy were determined for each group. The histologic diagnoses of the repeat biopsies were assessed. RESULTS: The rebiopsy rate was significantly lower with the 11-gauge vacuum suction probe (9.0%) than with the 14-gauge needle and automatic gun (14.9%) (p = .013). Significant reductions were found in cases of insufficient sampling (probe, 1.7%; needle, 4.4%; p = .042) and mammographic-pathologic discrepancy (probe, 0.8%; needle, 3.4%; p = .026). The rebiopsy rate for masses was 6.1% with the vacuum probe versus 10.7% with the 14-gauge needle (p = .12) and for calcifications was 11.6% with the vacuum probe versus 23.7% with the 14-gauge needle (p = .003). After rebiopsy, the percentage of cases in which malignancy was found was 18.5% with the vacuum probe versus 13.7% with the 14-gauge needle. On rebiopsy, the percentage of malignancies found in each category were atypical hyperplasia: probe 26.7%, needle 20.0%; insufficient sample: probe 0%, needle 9.5%; pathologist recommendation: probe 50.0%, needle 12.5%; and lobular carcinoma in situ: probe 0%, needle 100%. CONCLUSION: Use of the 11-gauge vacuum-assisted device significantly decreases but does not eliminate the need for rebiopsy after stereotactic core needle biopsy. The rebiopsy rate for calcifications was significantly reduced by using the vacuum suction probe rather than the 14-gauge needle; however, the rate for masses was reduced only slightly. On rebiopsy, malignancies were found in both groups.

Biopsy, Needle↗

PubMed2005

[Concept analysis of endotracheal suctioning (ETS)].

PURPOSE: Concept analysis was performed on the behavioral concept of endotracheal suctioning (ETS), to identify the goal, to develop a standardized clinical protocol, to identify the antecedents and consequences, and to differentiate the improper use of ETS. METHOD: Walker & Avant's concept analysis was employed using clinical guidelines, books and review articles in which the procedures of ETS were written in detail and published in Pubmed within the last 20 years. RESULT: The macro-goal of ETS was to remove accumulated respiratory secretions. Three defining attributes of ETS were identified; catheter, suctioning and asepsis. Each attribute involved empirical referents, such as the size and depth of the catheter, the suction pressure, duration and method for suctioning. The antecedents of ETS were identical to the clinical evidences for the need of ETS such as the nursing assessment data. The consequences of ETS serve as an evaluation criteria on the effects of ETS based on the goal of ETS. CONCLUSION: The concept analysis of ETS demonstrates an example of considering a specific nursing protocol of ETS as a behavioral concept, applying concept analysis to it to identify it's key behavioral components as defining attributes and empirical referents and then developing and applying the standard ETS protocol.

Humans↗

PubMed1997

Is the endometrial suction curette useful in the detection of chorionic villi during the first trimester?

OBJECTIVE: Early diagnosis of ectopic pregnancy is important for its medical management. Algorithms used for the diagnosis of ectopic pregnancy recommend obtaining a tissue diagnosis to rule out an intrauterine pregnancy when it is clear that a pregnancy is abnormal, but a stage of sonographic visualization has not been attained. The ability of an endometrial suction curette to identify products of conception early in pregnancy has not been documented. The purpose of this study was to determine the efficacy of an endometrial suction curette in detecting products of conception during the first trimester. METHODS: Twenty patients scheduled for termination of pregnancy via D&C agreed to endometrial sampling prior to dilatation of the cervix. All patients had transvaginal sonography which verified the gestational age. The specimen was evaluated microscopically after staining. RESULTS: Chorionic villi were identified in 14 of 20 (70 per cent) specimens as seen with light microscopy. CONCLUSION: An endometrial suction curette identifies chorionic villi from an intrauterine gestation in the first trimester with a sensitivity of 70 per cent. While most patients with an intrauterine gestation can be identified using an endometrial suction curette to obtain trophoblastic tissue, the absence of this tissue does not definitively identify an ectopic pregnancy. Therefore, the routine use of the endometrial biopsy in the algorithms for the diagnosis and treatment of ectopic pregnancy should be approached with caution.

Biopsy↗

PubMedDate not supplied

Effect of airway diameter, suction catheters, and the bronchofiberscope on airflow in endotracheal and tracheostomy tubes.

Pressure-flow relationships of an artificial airway-mechanical ventilator system were investigated. Endotracheal tubes varying from 7 to 9.5 mm. internal diameter and tracheostomy tubes from 7 to 10 mm. internal diameter were tested over flow-rates from 0.3 to 1.4 L. per second using a tidal volume of 500 ml. The effect of partial obstruction within these airways by suction catheters and the bronchofiberscope was examined. Depending on the internal diameter and the flow-rate, the driving pressure necessary to overcome the resistance of the tubes ranged from 5 to 20 cm. H2O. Partial obstruction of the artificial airways by suction catheters further increased this pressure. The introduction of the bronchofiberscope through an endotracheal tube of 7.5 mm. internal diameter, leaving an effective diameter of 4.9 mm., produced a driving pressure as high as 70 cm. H2O and reduced the flow rate to 50 per cent and the tidal volume to 80 per cent of its set value. Attention should be paid to duration of tracheobronchial suction while the patient is removed from the respirator since a high-grade resistance is created by passage of a suction catheter through an endotracheal tube. Bronchofiberscopy should be cautiously performed through cuffed artificial airways with at least 8 mm. internal diameter because the airway may be too comprised even if mechanical ventilatory assistance is employed.

Bronchoscopes↗

PubMed1975

A routine for safe, effective endotracheal suctioning.

A routine for safe, effective endotracheal suctioning is delineated. This routine was established by correlating various periods of augmented tidal ventilation and endotracheal suctioning with continuous arterial oxygen tension measurements. Patients were evaluated at bronchography to determine the effect of head position on suction catheter placement. Inspired oxygen concentrations were measured via an intratracheal catheter during various forms of inhalation therapy and modes of breating. Using these observations, guidelines were established to maximize the benefits and minimize the risks of an endotracheal suction routine.

Drainage↗

PubMed1977

Effects of infusion of cardiotomy suction blood during extracorporeal circulation for coronary artery bypass surgery.

The effects of infusion of cardiotomy suction blood during extracorporeal circulation were evaluated in 15 patients undergoing coronary artery bypass surgery without the use of a left ventricular vent. In Group I all cardiotomy suction blood was discarded. In Groups II and III cardiotomy suction blood was reinfused without and with Dacron wool filtration, respectively. Marked hematologic changes were noted in the pericardial samples which also were reflected in oxygenator samples obtained at the end of bypass. Although postoperative bleeding was significantly greater in patients from Group II as compared to Group I, no differences were seen in total intraoperative and postoperative transfusion requirements. No patient required reoperation for bleeding. Recirculation of larger volumes of cardiotomy suction blood potentially could contribute to bleeding problems in the immediate postoperative period.

Blood↗

PubMed1990

Pharmacokinetic studies of antibacterial agents using the suction blister method.

The suction blister technique was used for pharmacokinetic studies with sulfonamides and trimethoprim. Blisters produced by suction (-0.3 kg/cm2) for 1.5 h contained approximately 0.15 ml fluid with a protein content of 40-50% of that in plasma, the main protein fractions being present in the same ratio as in plasma. 2 g sulfaisodimidine was given as bolus injection, i.v. infusion or orally to groups of 4 volunteers. The peak blister fluid concentrations after oral administration (120 +/- 18 mmol/l) was only marginally lower than the concentrations after i.v. infusion (122 +/- 28 mmol/l) and i.v. bolus injections (134 +/- 37 mmol/l). The total drug blister fluid concentration started to decrease before the plasma level was reached. However the relative concentration increased from 53% of that in plasma at 8 h to 66% at 12 h after drug administration. Considering the protein binding of the drugs, the interstitial fluid levels of free drug were presumably higher than the plasma level after 8 h. Comparison of drug concentrations in blisters produced before and after the drugs were given showed higher concentrations in the latter for the first 2-6 h. However, after 8-12 h the concentrations of the drugs in the two types of blisters were similar. The suction blister method produces blisters of uniform size. The drug concentrations in different experiments showed the coefficient of variation for blister fluid concentrations to be no greater than for plasma levels. The consistent results of the standardized suction blister method makes this method useful for studying drug penetration to extravascular compartments in humans.

Adult↗

PubMed1990

[The function of 100% O2 suction key in Bennett 7200 microprocessor ventilator].

Tracheal suctioning of a patient on a ventilator may induce hypoxemia. Bennett 7200 microprocessor ventilator has an "100% O2 suction" key which is claimed to provide 100% oxygen for two minutes and switch back automatically when this function is set. Four 7200 ventilators were tested to verify this function. We found that the mean lag time varied from 20.1 seconds to 103.3 seconds and the mean recovery time varied from 33.0 seconds to 134.6 seconds according to the difference of initial tidal volume, ventilator rate and fractional inspired oxygen setting. When the ventilator was on "100% O2 suction", the delivered tidal volume was less than the preset tidal volume. In order to hyper-oxygenate and hyper-inflate the patient to prevent suction-induced hypoxemia, those finding should be taken into consideration when the clinicians apply this function in clinical situation.

Evaluation Studies as Topic↗

PubMed1990

Fulminant adult respiratory distress syndrome after suction lipectomy. A case report.

The adult respiratory distress syndrome developing within 24 hours in a patient who underwent suction lipectomy for body contouring under general anaesthesia is reported. During surgery, in which a total of 1.3 l of suction matter was removed, the patient became haemodynamically unstable and mildly hyperthermic. Subsequently, clinical signs and symptoms of the fat embolism syndrome developed. Aggressive haemodynamic and respiratory support over an 8-day period resulted in patient survival. Malignant hyperthermia was excluded as cause for the clinical presentation on muscle biopsy and in vitro caffeine contracture studies. Although usually complication-free, suction lipectomy may be associated with life-threatening incidents. Even suction volumes as low as 1.3 l have potential hazards, therefore the procedure merits regular postoperative observation and re-assessment.

Adult↗

PubMed1993

[Suction lipectomy for male gynecomastia].

This paper reports the application of the suction lipectomy to treat gynecomastia in 10 cases with excellent results. A 2-2. 5 cm incision was made on the lower areolar border at 5 to 7 o'clock. The suction power was adjusted to 67-93 kPa. The suction cannula was moved to and fro in radial direction rapidly. The diameter of the sucked area should be larger than desired size of the breast by 2 cm to avoid a saucer deformity. If gynecomastia is entirely due to fat accumulation, suction lipectomy only is enough. But, when gynecomastia is due partly to parenchymal hypertrophy, an additional excision of the parenchymatous tissue is required. After the operation, elastic garment must be worn at all time for 4 to 6 weeks to avoid hematoma and to achieve a flat appearance.

Adult↗