Balloon Assembly Research Articles

Effect of Vascular Lumen Reduction on the Performance and Energy Consumption of an Innovative Implantable LVAD

This paper presents the results of a study on the effect of vascular lumen reduction on the performance of an innovative implantable LVAD (left ventricular assist device). It details the pressures in the individual cardiac chambers as a function of device frequency. In addition, mass flow rates and energy consumption of the device are examined, varying with lumen reduction and operating frequency. While the lumen reduction of the vessels has little effect on energy consumption, the mass flow rates vary considerably, i.e., above 140 cyc/min, the mass flow rate increment is no longer achieved for specified initial conditions. There are also differences regarding the pressures in the heart; namely, it was found that the pressure plots look similar in all cases, leading to the conclusion that the reduction of the vessel lumen does not affect their shape, but does affect the maximum values of the left ventricular and aortic pressures. Importantly, the innovative device in the form of an intra-cardiac balloon assembly for circulatory support is based on a pulsatile flow strategy and is synchronized with the ECG signal. Other advantages of the proposed solution include a minimally invasive method of implantation, which is important for patients with end-stage heart failure. The design of the device is portable and the device itself is battery-powered, allowing for shorter hospitalization times and faster recovery, even in patients with end-stage heart failure associated with mitral regurgitation and pulmonary hypertension.

A Novel Brachytherapy Endoscopic Tandem and Inflatable Ovoids Applicator for Cervical and Uterine Neoplasms

Brachytherapy using the Fletcher-Suit-Delclos (FSD) applicator is an effective treatment modality for cervical and uterine cancers. The traditional FSD applicator typically consists of 8-pieces that are assembled in the patient under anesthesia. The procedure can be lengthy due to difficulty visualizing the cervical os, poor applicator design and assembly difficulty. The purpose of this study is to build prototypes of a user-friendly applicator, which improve patient comfort and care while minimizing intravaginal manipulation and optimizing inter fractions reproducible geometry with superior dosimetric properties. 3D CAD software was used to create a model of an applicator and simulate its intended functionalities. A CT and MRI friendly prototype made of balloons and plastics manufactured based on the CAD model. The prototype device is comprised of two main pieces; an endoscopic tandem using a miniaturized Complementary Metal Oxide Semiconductor (CMOS) camera connected to a computer and two inflatable ovoids. The ovoids consist of a two inflatable balloon assembly that can be inserted simultaneously and attached to the already placed tandem, and be inflated with different volumes of water. Further, balloon retractors were designed to separate the bladder and the rectum from the implant plane. The prototype was assembled with CT and MRI scans acquired. Isodose lines for a 7Gy dose to point A were generated. Our preliminary tests found an easier and faster assembly of the endoscopic tandem and inflatable ovoids. All the minor adjustments to an ideal geometry can be done outside the patient similar to a laparoscopy procedure minimizing intravaginal manipulations. The endoscopic tandem easily visualizes the cervical os while prevents the perforations or injury to the uterus. The bladder and rectal balloons replacing the painful gauze packing and inflate to get a bladder and rectum displacement of >2cm from the plane of the implant sparing the organs at risk significantly. Our initial estimates indicate that our device will decrease the implant times significantly, reducing the time under anesthesia, while promoting patient safety, complication reduction, and lowering overall treatment cost. The applicator CT and MRI images confirmed applicator’s compatibilities with these imaging modalities. The endoscopic tandem improves cervical os visibility and overall tandem placement. Further, with up to 15% of the tandems causing uterine perforation, using the camera aids in preventing the injury and potential morbidities associated with it. We achieve significant improvement in sparing the bladder and the rectum while delivering the same dose as the conventional FSD device. A comparative implant and dosimetric studies in a phantom with the applicators currently in clinical use are warranted in future studies.

Gastric administration of garlic powder containing the trpa1- agonist allicin induces specific epigastric symptoms and gastric relaxation in healthy subjects.

TRPA1 is an excitatory ion channel and is involved in sensory processes including thermal nociception and inflammatory pain. The allicin in garlic is a strong activator of the TRPA1 channel. To evaluate the effect of intragastric garlic powder containing allicin on perception, gastric tone, and mechanosensitivity. An infusion-barostat balloon assembly was used for infusion of test solutions, for distension, and to measure proximal gastric compliance and tone. After an initial open label dose finding with 1g, 2g, 3.75g, and 7.5g commercially available garlic powder, a bolus of 2g garlic powder (11mg allicin)/60mL H2 O was considered to induce moderate but constant sensation and was used hereafter in a placebo-controlled, single-dose, double-blind, randomized study in 7 volunteers to evaluate gastric sensation, tone, and mechanosensitivity. Bolus injection of garlic caused immediate epigastric symptoms, mean aggregate symptom scores (AUC in 15minutes) were 106±49 vs. 35±30 after placebo (P=0.01). Garlic induced significant epigastric pressure, stinging, and warmth (P<0.01 vs. placebo), while intensity of cramps, satiety, nausea, and pain was not significantly different to placebo (P>0.05). Garlic induced an immediate, short lived fundic relaxation (balloon volume 627±349mL vs. -145±120mL; P<0.02). No effect of allicin on proximal gastric mechanosensitivity and compliance was observed (NS). Garlic containing allicin induces immediate epigastric symptoms of pressure, stinging, and warmth and induces fundic relaxation but does not influence mechanosensitivity or compliance. TRPA1 is a receptor that is involved in gastric sensation and motility.

Structural Integrity of a Simple Method to Repair Disrupted Tracheal Tube Pilot Balloon Assemblies.

An intact pilot balloon assembly is crucial to the proper function of a cuffed tracheal tube. Disruption of the pilot balloon, transection of the inflation line, or valve incompetence results in cuff deflation, which may lead to inadequate ventilation and aspiration of secretions. Such failures typically result in tracheal tube replacement, but this may be a safety risk if a difficult reintubation is anticipated. We recently encountered such a patient who remained intubated postoperatively and in whom the inflation line was transected, causing a large leak. We describe a method to reconstitute the inflation line and report on the structural integrity of the repair. We hypothesized that the repaired assembly would maintain cuff pressure not statistically different from an intact device, but that the inflation line would be weaker. The distal (tapered) portion of a 22-gauge intravenous (IV) catheter was partially inserted into the severed end of the inflation line. A new pilot balloon was cut from an intact tracheal tube with the tubing attached, the end of which had been dilated using a 22-gauge IV catheter. The new tubing was then guided over the protruding portion of the catheter, creating an internal stent. We measured the drop in cuff pressure after 8 hours in an artificial trachea for repaired and intact tracheal tubes. We tested the integrity of the repaired segments, underwater, to high-pressure inflation. We measured the static tensile strength of the inflation line from intact and repaired tracheal tubes. Data are presented as the mean ± standard error. Differences were assessed using the unpaired, 2-sided Student t test, with P < .05 required to claim statistical significance. Eight-hour interval measurements in 10 intact versus 10 repaired tracheal tubes demonstrated no significant difference in pressure drop (mean difference = 0.5 cm H2O; 95% confidence interval, -2.2 to 1.2 cm H2O; P = .54). There was no visible air leak from 10 repaired inflation line segments when the cuff was inflated to 120 mm Hg. The force needed to break the repaired inflation line was lower than for the intact tubing (n = 7 of each; mean difference = -21.9 N; 95% confidence interval, -25.7 to -18.1 N; P < 10). Repairs to tracheal tubes from various manufacturers with inner diameters ranging from 3.0 to 8.0 mm were successful. Repairing a disrupted pilot balloon assembly using an IV catheter as a stent inside the inflation line is an effective temporizing measure in situations where ventilation is impaired and where tracheal tube replacement may present an excessive patient risk.

Short-Term Effects of Relamorelin on Descending Colon Motility in Chronic Constipation: A Randomized, Controlled Trial.

The pentapeptide ghrelin agonist, relamorelin, accelerates colonic transit in patients with chronic constipation (CC). In a murine model, relamorelin decreased excitability of colonic circular smooth muscle cells and colonic intraluminal pressure. To determine short-term effects of relamorelin on colonic motility measured by barostat and multilumen manometry in CC. In a placebo-controlled, single-dose, double-blind, randomized study in patients with CC, we investigated the motor effects of relamorelin, 100 μg, SQ (12 patients) compared to placebo SQ (six patients). A motility-barostat balloon assembly was used to measure colonic compliance; tone and phasic pressure activity were measured before and after a 1000-kcal milkshake meal (administered ~60 min post-medication). Overall "background" phasic pressure activity was assessed by: average amplitude and motility index (MI = ln[sum amplitudes × #contractions + 1]) over defined periods. High-amplitude propagating contractions (HAPCs) were characterized by amplitude >75 mmHg and propagating contractions >50 mmHg; both were propagated over at least 10 cm. Postprandial HAPCs were the primary end point. The study sample had 80% power to detect an increase of 3.3 HAPCs in the hour post-meal. Relamorelin, 100 μg, significantly induced more pre-meal propagated contractions [PCs of either >50 or >75 mmHg] compared to placebo (p < 0.05). Relamorelin also induced more post-meal PCs >50 or >75 mmHg than placebo. Relamorelin did not significantly alter colonic compliance, fasting or postprandial phasic pressure activity (20 min pre-meal fasting MI) or tone, and 60 min postprandial phasic pressure amplitude or MI, or tone. Relamorelin stimulates propagated colonic contractions without alteration of background irregular contractions in CC. ClinicalTrial.Gov registration number: NCT 01781104.

Stenting for curved lesions using a novel curved balloon: Preliminary experimental study

BackgroundStenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. Materials and methodsIn vitro experiments: A Palmaz Genesis® stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku® curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express® Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express® Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. ResultsIn vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. Animal experimentIn the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. ConclusionThis novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length.

Contribution of different triggers to the gastric accommodation reflex in humans

Accommodation of the stomach consists of a vagally mediated relaxation of the proximal stomach, providing the meal with a reservoir. Our aim was to study whether, similar to other vagally mediated processes, the accommodation reflex is also determined by cephalic, oropharyngeal, gastric, and intestinal phases. Eleven healthy subjects underwent in randomized order five gastric barostat studies and two satiety drinking tests. In all studies, isobaric tone measurements (at minimal distending pressure + 2 mmHg) were performed 20 min before and 20 min after a nutrient stimulus. The stimuli included only visual and olfactory exposure to a meal (cephalic stimulation), taking liquid nutrient in the mouth without swallowing (sham feeding), ingestion of a 200-ml 300-kcal nutrient meal with blocked outflow to the pylorus (gastric retention), and meal infusion through a nasointestinal tube (duodenal instillation), or normal ingestion (control). During satiety testing, subjects ingested liquid nutrient at a fixed rate of 15 ml/min until maximum satiety, with an inflated or deflated intrapyloric balloon assembly. Progressively bigger gastric relaxatory responses were seen with cephalic stimulation (18 +/- 19 ml), sham feeding (54 +/- 21 ml), gastric retention (95 +/- 47), duodenal instillation (144 +/- 33), and control (232 +/- 33 ml). The amount of nutrient ingested at maximum satiety was significantly lower with an inflated intrapyloric balloon (1,223 +/- 103 vs. 1,392 +/- 124 ml, P < 0.05). The accommodation reflex in humans lacks a cephalic phase, but it can be activated from the oropharynx, the stomach, and the duodenum. Blocking passage to the duodenum significantly decreases the amplitude of the accommodation reflex and induces early satiety.

Management of pilot balloon assembly malfunction in an armored endotracheal tube in a child

Management of pilot balloon assembly malfunction in an armored endotracheal tube in a child

Effect of acute hyperglycemia on colorectal motor and sensory function in humans.

Increased use of laxatives and constipation are more common among people with diabetes mellitus than matched nondiabetic people in the same community. The mechanism of constipation in diabetes is unclear. Acute hyperglycemia was previously reported to reduce the gastrocolonic response. Our aim was to determine the effects of acute hyperglycemia on the colon compliance and motor response to feeding and on the sensory function of the colon and rectum in healthy human subjects. Eleven healthy individuals were studied under conditions of hyperglycemia (mean blood glucose 280 +/- 13 mg/dl) and euglycemia. We evaluated three parameters: 1) colonic motility and compliance by a multilumen manometry and barostatic balloon assembly in the descending colon (motility was studied during fasting and for 2 h postprandially); 2) perception of isobaric distensions of polyethylene balloons in the rectum and colon; and 3) rectal compliance. Initial tonic response to meal ingestion (0-5 min) was slightly lower during hyperglycemia (P = 0.3). However, colonic tone, motility, compliance, and sensation, as well as rectal compliance and sensation, were not significantly different under the conditions of euglycemia and acute hyperglycemia. In healthy individuals, acute hyperglycemia does not significantly change colonic or rectal motor functions or the perception of mechanosensory stimuli in the colon or rectum compared with euglycemia. These results do not support the hypothesis that hyperglycemia abolishes the colonic response to feeding.

Centering balloon to improve esophageal photodynamic therapy.

A cylindrical balloon was developed to improve delivery of circumferential light for photodynamic therapy (PDT) of esophageal carcinoma. The balloon consisted of a 36-mm-long clear cylindrical membrane and a central tube to hold a cylindrical diffuser in the center of the lumen. Three isotropic probes were placed on the outside of the balloon to allow measurement of delivered light dose to the esophageal mucosa. The balloon was tested in the normal esophagus of 8 dogs that were injected with 4.0 mg/kg of PHOTOFRINR. Endoscopy was performed 48 hours following the injection, and under endoscopic observation the balloon assembly was passed, fixed in place, and inflated. A 1-cm cylindrical diffuser was passed into the central tube and 150, 300, and 600 Joules/cm of 630 nm laser light was delivered at 25 cm, 15 cm, and 5 cm proximal to the gastroesophageal junction. One control dog was illuminated using the cylindrical diffuser alone at doses of 300 and 600 Joules/cm of diffuser. Complete circumferential tissue response was obtained when the balloon was used. Relatively uniform light intensities were measured around the lumen. In contrast, noncircumferential and unpredictable PDT responses were generated when the cylindrical diffuser was used without the balloon.

Linear-quadratic-regulator pointing control system for a high-altitude balloon payload

A pointing control system design for the science package of a NASA high-altitude research balloon is described. The balloon assembly consists of a single helium balloon connected to a payload recovery parachute, payload gondola, and ballast hopper. Pointing of the scientific payload is accomplished via an arrangement of drive motors and a flywheel. Linear quadratic regulator (LQR) synthesis techniques are employed to produce the azimuth and elevation controller designs. The use of LQR synthesis is motivated by the azimuthal dynamic coupling encountered between the balloon and gondola. Two control devices are employed in azimuth, one of which is a decoupler motor and the other a flywheel. The decoupler motor is intended to isolate the gondola from the balloon such that the flywheel can be accelerated or decelerated about a steady-state angular velocity to provide precise azimuthal pointing. The multiple-input/multiple-output nature of the azimuth pointing problem is best handled in a matrix synthesis procedure such as LQR. The controller design methodology is explained, and a combination of time responses and singular value analyses are used to analytically evaluate the performance of the control system. 11 refs., 17 figs.

Sensory discrimination training in the treatment of a case of chronic constipation

A 31-year-old woman with a history of life-long constipation and laxative dependence was treated with discrimination training for rectal sensation. She had complained of absence of the urge to defecate, bloating with abdominal discomfort, and need for laxatives to relieve symptoms. Manometric examination with an anorectal balloon assembly revealed a normal threshold for sphincteric reflexes, but an abnormally elevated threshold for detection of rectal distention. Behavioral treatment consisted of a manometrically based sensory discrimination procedure designed to reduce the sensory threshold for rectal distention. Multiple training sessions with this procedure allowed recognition of progressively smaller rectal distention volumes. Accompanying these changes in rectal sensory threshold were concomitant increases in the frequency of bowel movements, decreases in the weekly use of laxatives, and decreases in subjective discomfort. Therapeutic effects were maintained at follow-up examination one year later. The results of this case study suggest that behavioral training to increase rectal sensation may be useful in treating constipation in patients who have abnormal rectal sensory thresholds.

Treatment of achalasia with a pneumatic dilator attached to a gastroscope.

A pneumatic dilator for the treatment of achalasia of the esophagus is described. An inflatable polyurethane balloon assembly is attached to a small-caliber forward-viewing fiber-optic gastroscope. The balloon is introduced and dilatation carried out under endoscopic visual control. The described method greatly increases the safety and accuracy of the dilatation procedure, even in patients with an extreme degree of megaesophagus. 39 patients have been successfully treated with the dilator with no complications.