Evaluation of Adrenergic Function: Tilt-Table and Valsalva Test

Summary Aim: Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for TI-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. Methods: In 201 consecutive patients unable to perform adequate exercise, dobutamine TI-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 μg/kg/min increasing to 40 μg/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure ≥ 20 mmHg compared with baseline study. Results: Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39 ± 18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. Conclusion: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise test, hypotension response to dobutamine is not always a marker for coronary artery disease.

Download Full-text

A Stepping Mechanism in Tilt Table Mobilization can Prevent Syncopes in Patients with Traumatic Brain Injury. A Case Report

Klinische Neurophysiologie ◽

10.1055/s-2006-939230 ◽

2006 ◽

Vol 37 (01) ◽

Author(s):

M Luther ◽

C Krewer ◽

F Müller ◽

E Koenig

Keyword(s):

Traumatic Brain Injury ◽

Case Report ◽

Brain Injury ◽

Tilt Table

Download Full-text

In-Situ Mechanical Sample Preparation of Selected Sites and Components on Large Modules and Boards

ISTFA 2016: Conference Proceedings from the 42nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2016p0362 ◽

2016 ◽

Author(s):

Jim Colvin ◽

Timothy Hazeldine ◽

Heenal Patel

Keyword(s):

Sample Preparation ◽

Printed Circuit Board ◽

Circuit Board ◽

Tilt Table ◽

Standard Requirement ◽

Open Design ◽

Bga Packages ◽

Silicon Thickness ◽

Board Level

Abstract The standard requirement for FA Engineers needing to remove components from a board, prior to decapsulation or sample preparation, is shown to be greatly reduced, by the methods discussed here. By using a mechanical selected area preparation system with an open-design it is possible to reach all required areas of a large printed circuit board (PCB) or module to prepare a single component ‘in situ’. This makes subsequent optical or electrical testing faster and often more convenient to accomplish. Electronic End-pointing and 3D curvature compensation methods can often be used in parallel with sample prep techniques to further improve the consistency and efficacy of the decapsulation and thinning uniformity and final remaining silicon thickness (RST). Board level prep eliminates the worry of rework removal of BGA packages and the subsequent risk of damage to the device. Since the entire board is mounted, the contamination is restricted to the die surface and can be kept from the underside ball connections unlike current liquid immersion methods of package thinning or delayering. Since the camera is in line with the abrasion interface, imaging is real time during the entire milling and thinning process. Recent advances in automated tilt-table design have meant that a specific component’s angular orientation can be optimized for sample preparation. Improved tilt table technology also allows for improved mounting capability for boards of many types and sizes. The paper describes methods for decapsulation, thinning and backside polishing of a part ‘in situ’ on the polishing machine and allows the system to operate as a probe station for monitoring electrical characteristics while thinning. Considerations for designing board-level workholders are described – for boards that that are populated with components on one or even both sides. Using the techniques described, the quality of sample preparation and control is on a par with the processing of single package-level devices.

Download Full-text