Balloon Position Research Articles

Anatomic basis for and morphologic results from catheter balloon valvuloplasty of stenotic mitral valves

This report provides the anatomic basis for catheter balloon valvuloplasty procedures. The morphologic hallmark of mitral stenosis is commissural fusion and the major mechanism of successful balloon valvuloplasty is commissural splitting. Single and double dilating balloons are used to increase the cross-sectional orifice area of stenotic mitral valves. Double balloons appear to improve the luminal diameter and cross-sectional area compared with single balloons. This report also illustrates the anatomic basis for single and double balloon catheter placement and position using the transseptal approach.

Testing a Mobile Version of a Cross-Chain Loran Atmospheric (M-CLASS) Sounding System

Abstract We have Rested the NCAR Cross-Chain LORAN Atmospheric Sounding System (CLASS) in a fully mobile configuration, which we call M-CLASS. The sondes use LORAN-C navigation signals to allow calculation of balloon position and horizontal winds. In nonstormy environments, thermodynamics and wind data were almost always of high quality. Besides providing special soundings for operational forecasts and research programs, a major feature of mobile ballooning with M-CLASS is the ability to obtain additional data by flying other instruments on the balloons. We flew an electric field meter, along with a sonde, into storms on 8 of the initial 47 test flights in the spring of 1987. In storms, pressure, temperature, humidity, and wind data were of good quality about 80%, 75%, 60%, and 40% of the time, respectively. In a flight into a mesocyclone, we measured electric fields as high as −135 kV/m (at 10 km MSL) in a region of negative charge. The electric field data from several storms allow a quantitative assessm...

Neurovascular lesions and endovascular therapy: the role of MR.

Magnetic resonance imaging (MRI) studies were performed on 27 patients with vascular lesions of the central nervous system before and after embolization with either IBCA, polyvinyl alcohol foam particles, Avitene (microfibrillar collagen) or balloons. Thirteen pial brain arteriovenous malformations (AVMs), 3 brain AV fistulas, 2 giant aneurysms, 5 dural AVMs, 1 vertebro-vertebral fistula and 3 meningiomas were studied. The pre-embolization MR demonstrated the nidus and venous drainage of all pial AVMs. MR failed to detect 3 out of 5 dural AVMs using only spin echo sequences. A draining vein alone was seen in the remaining two cases. MR was superior to CT in detecting contiguous parenchymal changes such as atrophy, reversible ischemia, and mass effect in the pre-embolization studies. Following embolization, MR demonstrated partial or complete obliteration of the vascular nidus in all 13 pial AVMs. The embolized area was seen as an area of increased signal consistent with thrombus where previously there had been signal void. Ischemic or edematous changes in the brain parenchyma following embolization were seen on MR more easily than on CT scans. MR was accurate in the assessment of aneurysm patency, degree of thrombosis and balloon position in both giant aneurysms, and AV fistulae. These MR findings had an impact on patient management. MR will be an increasingly useful tool in the diagnosis and management of a number of neurovascular diseases requiring endovascular intervention.

Summertime stratospheric wind measurements above the South Pole

Observations of the mean wind flow and wave motions in the stratosphere at the South Pole are presented. The atmospheric motions are determined from the tracking of a high altitude, zero-pressure balloon launched from Amundsen-Scott Station during the austral summer of 1985–1986. The balloon position was precisely monitored by an optical theodolite for a large portion of the flight so that small scale motions could be resolved. The mean flow above the pole was approximately 3ms −1. Atmospheric motions characteristic of internal gravity waves were observed with an intrinsic period of approximately 4.5 h and vertical and horizontal wavelengths of approximately 2.5km and 125km, respectively. The horizontal perturbation velocity of the observed waves was large compared to the mean horizontal flow velocity. The implication is that wave motions play a dominant role in the transport of stratospheric constituents in regions where the mean winds are light, such as over the South Pole during austral summer.

Observations of the electric field in the stratosphere over an arctic storm system

Observations by balloon‐borne instrumentation in the stratosphere (30–35 km) near Sondre Stromfjord, Greenland, have revealed disturbed vertical electric fields of the order of volts per meter of both polarities above an arctic storm system which moved onto the continent from the Davis Strait on August 11, 1982. This disturbance persisted at the balloon position for more than 10 hours, exhibiting order of magnitude variations with time scales ranging from minutes to hours. Simultaneous measurements of the stratospheric electrical conductivity did not show significant storm‐related variations. No lightning signals were detected, either at the balloon or at meteorological stations in the Davis Strait area. The disturbed field was predominantly downward (normal fair‐weather direction), and estimates of the total current indicate that at any instant a current of the order of 0.5 A was communicated to the storm system via the overlying stratosphere. The responsible storm system has been uniquely identified by NOAA 7 satellite IR (10.5–11.5 μm) imagery, and the infrared measurement of cloud‐top temperatures has revealed zones of enhanced convection lying in the storm's interior. Meteorological measurements taken at the surface and from balloon radiosondes by stations in the path of the storm also suggest that the storm possessed convective instabilities of the type likely to produce cloud electrification. In tropospheric features this type of storm occurs rather frequently on the western Greenland coast; therefore electrical charging of the storm cloud systems may not be as rare as indicated in the low probabilities observed for thunder and lightning.

Balloon embolization to occlude a Blalock-Taussig shunt

Balloon embolization was used to successfully occlude a large residual Blalock-Taussig shunt. The use of an "upstream" nondetachable balloon catheter to reduce flow and turbulence during final positioning of the detachable balloon may have made the technique safer and more precise.

An improved technique for circular myotomy in long-gap esophageal atresia

Circular myotomy has allowed the surgeon to establish esophageal continuity in early infancy in patients with long-gap esophageal atresia. This report describes the use of a #5 Fogarty balloon catheter, passed by the surgeon into the proximal esophagus to facilitate the myotomy. The catheter is passed through a pursestring suture placed at the tip of the proximal esophagus. The balloon is inflated to fill but not distend the lumen. The myotomy is performed approximately two cm proximal to the esophageal end and; upon its completion, it will provide 1 to 1.5 cm of additional length. The advantages of the surgeon placing the catheter into the esophagus include: complete control of the balloon size and position, and the ability to use the catheter to manipulate the proximal esophagus atraumatically.

Echocardiographically Assisted Balloon Atrial Septostomy

Balloon atrial septostomy is an accepted method for palliation of certain types of congenital heart disease. However, malposition of the balloon may lead to cardiac perforation, avulsion of an atrioventricular valve, or laceration of the systemic or pulmonary veins. Inasmuch as single-phase fluoroscopy may not identify balloon position correctly and as biplane fluoroscopy adds significant radiation exposure, two-dimensional echocardiography has been used to assist in balloon atrial septostomy in ten infants. The catheter is advanced from the inferior vena cava to the right atrium across the foramen ovale to the left atrium with the echo transducer in the subxiphoid position. The balloon is inflated and its position within the left atrium is confirmed by echo. The catheter is withdrawn according to the technique of Rashkind. Withdrawal is halted when the balloon traverses the atrial septum. Adequate septostomy is indicated on echo by a defect at least 5 mm in diameter and by flapping of the inferior rim of the atrial septum. There were no complications using this technique and a clinically adequate septostomy was achieved in each patient. Two-dimensional echocardiography-assisted balloon atrial septostomy minimizes risk of complications and decreases exposure to ionizing radiation.

Controlling Inherent Uncertainties in Double Theodolite Measurements

Abstract This note examines the uncertainty inherent in calculations of wind speed, wind direction, temperature lapse rate and balloon height as determined by double theodolite-pibal/minisonde techniques. It is found that short observation intervals intended to provide good spatial resolution can lead to balloon position uncertainties so large as to make the derived data quite unreliable. The same problem occurs with short baselines or inadequate angle resolution. A double-theodolite field program is recommended which maintains the best possible spatial resolution consistent with acceptable levels of confidence in the measurements.

OESOPHAGEAL PRESSURE MEASUREMENT IN RABBITS AND HUMAN INFANTS USING AN AIR-FILLED BALLOON SYSTEM

In ventilated anaesthetized rabbits the relationship between the oesophageal pressure and the intrapleural pressure, measured with an air-filled balloon system, was studied. A balloon 15 mm long and 3 mm diameter detected 95% of the measured intrapleural pressure, provided the balloon was positioned accurately. In babies undergoing IPPV, the best balloon position was in the lower third of the oesophagus. When synchronous spontaneous respiration occurred in the course of IPPV the mean of intrapleural pressure remained negative in spite of positive ventilating pressures in the range 30-45 cm H2O.

Air motions in the tropical stratosphere deduced from satellite tracking of horizontally floating balloons

Between June and November of 1970, 26 constant level balloons were released from Ascension Island (8 S) for flight at 30 and 50 mb. The balloons were positioned by the Interrogation, Recording and Location System (IRLS) aboard the Nimbus D satellite. In general, balloon positioning appeared to be accurate to within a few kilometers, although occasionally there was doubt as to whether the balloon position was to the right or left of the satellite subtrack. Eight of the flights at 50 mb and three of the flights at 30 mb were tracked for more than one month, and one 50 mb flight was tracked continuously for more than 5 months while making 7 circumnavigations of the Earth. From the satellite-determined 12-hourly balloon positions in the tropics, 223 smoothed 24-hour-average zonal and meridional winds were obtained at 30 mb and 693 such winds were obtained at 50 mb. Near the equator the balloons moved from east to west at a speed of about 23 ms−1 at 50 mb and 28 ms−1 at 30 mb, while undergoing a mean northward drift of approximately 0.1 ms−1. The northward drift was a maximum in the Northern Hemisphere winter, suggesting a weak upward extension of the Hadley Cell to 50 mb. Superimposed on this drift were oscillations in meridional velocity of about 2-month period, with these oscillations also most pronounced in the Northern Hemisphere winter. Small (1–3 ms−1) short-period fluctuations in meridional velocity were evident directly above the equator at 50 mb. These waves appear to move westward at speeds of 30–40 ms−1 and to have a wavelength of about 90° longitude. They were responsible for transporting small amounts of westerly momentum into the winter hemisphere. Fluctuations in zonal velocity (Kelvin waves) were also delineated by flights near the equator. These waves appear to move eastward at speeds of 30–40 ms−1 and to have a wavelength of 360° longitude. Some comparisons are made between these IRLS data and the data obtained from GHOST balloon flights at the same heights in early 1969.

Mechanics of breathing in mitral stenosis.

The mechanical properties of the lungs of patients with mitral stenosis were studied using the esophageal balloon technique. Both the position and the volume of the balloon were systematically varied in an effort to detect artifacts in the pressure tracings ascribable to the heart and great vessels. No artifacts were found; variations in esophageal pressure induced by changing balloon position and volume were similar to those seen in normal subjects. In patients with mitral stenosis, the static pressure-volume curve of the lung was abnormal in a unique way; at large lung volumes transpulmonary pressures were high, but at small lung volumes, recoil was diminished. It was suggested that vascular plethora accounted for loss of recoil at small lung volumes and pulmonary fibrosis caused increased recoil at larger volumes. This hypothesis was supported by studies on patients with atrial septal defects who showed loss of recoil at small lung volumes. Both static and dynamic compliances were sharply reduced in mitral stenosis. Although it was examined over a rather limited range, dynamic compliance did not decrease as breathing frequency increased. Airway resistance was approximately twice normal, and this abnormality tended to dominate the maximal expiratory flow-volume curve; expiratory fiows were decreased at all lung volumes.

POSITION DETERMINATION METHODS USED TO TRACK SUPERPRESSURE BALLOONS

Abstract The method that has been used in the past to determine the position of superpressure balloons employed in long-term meteorological and technological experiments—projects GHOST (Global Horizontal Sounding Technique), EOLE (French, God of the Winds), SOMEX (Solar Monitoring Experiment), etc.—was to measure the solar elevation during the daylight hours and then compute the balloon position at local noon: latitude by the noon solar altitude and longitude by the time of balloon noon. This method has disadvantages: it requires a lengthy series of measurements during the day and has degraded accuracy when the maximum solar angle approaches 90°. Another method was therefore devised in which the solar angle data are complemented by data that indicate the local geomagnetic rigidity; the correlation of the two data yields an improved position determination algorithm. This method was applied to the trajectory determination of the SOMEX balloons with considerable success.

Windfinding Using the Loran-C and Omega Long Range Navigational Systems

This paper describes a weather balloon tracking system designed to be both portable and quickly erectable. The purpose of this system is to enable upper air soundings to be made over the oceans from rented space on merchant vessels. The system is based upon the telemetry of existing long range navigational aids for determining relative balloon position and track. Details of instrumentation are given, along with results of flight tests performed in the latter part of 1966.

Some characteristics of the large-scale Lagrangian eddy frictional force in the atmosphere

The Lagrangian eddy frictional force for mean motion in the atmosphere is defined and evaluated. The average magnitude of the Lagrangian eddy frictional force is found to be at least as significant as the magnitude of the average acceleration term. Analyses of the eddy frictional force following balloon trajectories in planetary waves in the upper troposphere show that a predominantly cyclonic rotation of the force occurs in all parts of waves of various amplitudes and phase speeds. It is found that this force seems to resist the motion of the balloon in the vicinity of the ridge line regardless of the balloon's position with respect to the jet stream core. As the balloon moves from the ridge toward the trough, it rotates cyclonically from the upstream direction. By the time the balloon reaches the inflection point of the wave, the force vector rotates to a direction predominantly normal to the direction of motion and toward lower pressure. It is also found that the tangential component of the Lagrangian eddy frictional force is of the same order of magnitude as the tangential component of the pressure force.

Double Theodolite Pibal Evaluation by Computer

Abstract The position of a pilot balloon, which is being followed by two theodolites, can be computed by using all four theodolite angles to make an optimum estimate of the balloon's position and also indicate the probable magnitude of the error in its position. The method described does not fail when the balloon is near or over the base-line, and it is suitable for digital computers.

Report on stratosphere research at the University of Rochester

With aid from the Smithsonian Institution, we have undertaken a preliminary study of fluctuations in the ultra‐violet output from the Sun. In order to free these measurements as far as possible from uncertainties in atmospheric transmission it has seemed desirable to attempt them from high‐altitude sounding‐balloons working well into the stratosphere. At present we are using filters to isolate a wave‐length region slightly longer than the Hartley band of ozone, so that there are no uncertainties in atmospheric transmissions due to fluctuation either in the amount or vertical distribution of the ozone.In connection with this program we have completed a subsidiary development which is of interest in upper‐air exploration with sounding‐balloons. The development involves a procedure and instruments for the continuous triangulation upon a balloon while in flight, and the transmission of the balloon's position to a pick‐up car, or cars, in the field, in order to expedite the recovery of valuable apparatus. The development is not completed in all respects, but that part pertaining to the continuous triangulation and plotting during the balloon's flight is complete, and has been through successful field‐tests. In principle it is, of course, very simple. In detail, however, it has required the development of two unusual balloon‐theodolites of great telescopic power, and a mechanical plotting‐instrument of accuracy comparable to the theodolites to permit minute‐to‐minute determination of the coordinates of the balloon in space. The scheme has proved workable, even with very small sounding‐balloons, up to distances of 100 km or more and provides a powerful tool for this class of work.