| 1. |
- Ask, Per, 1950-, et al.
(författare)
-
Clinical evaluation of different fluid-filled systems for oesophageal manometry
- 1979
-
Ingår i: Scandinavian Journal of Gastroenterology. - 0036-5521 .- 1502-7708. ; 14:1, s. 1-5
-
Tidskriftsartikel (refereegranskat)abstract
- In a clinical study of oesophageal manometry with fluid-filled catheters, both a non-perfused system and a perfused system with a syringe pump have been compared to a system with a low-compliance perfusion pump, which served as a reference. Significantly lower values of motility amplitudes, motility derivatives, and partly of LES pressures, and a time delay of up to 0.5 sec of the amplitude maximum were obtained with the non-perfused system and the system with a syringe pump in comparison to the low-compliance system. Since the oesophageal function can be erroneously evaluated by use of a non-perfused system or a perfused system with a syringe pump, such systems cannot be recommended for clinical use.
|
|
| 2. |
- Ask, Per, 1950-, et al.
(författare)
-
ECG Electrodes : A Study of Electrical and Mechanical Long-term Properties
- 1979
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 23:2, s. 189-206
-
Tidskriftsartikel (refereegranskat)abstract
- The long-term properties of commercially available ECG-electrodes were studied by investigating the parameters: polarization potential, electrical impedance, adhesion, and skin reactions during a period of 7 days. As expected, the most stable polarization potentials were obtained for Ag/AgCl electrodes. Certain simple disposable electrodes showed large polarization potential variations. The most stable electrode impedance was obtained for disposable electrodes with stable adhesion and equipped with an electrode cup or similar. Unchanged adhesion and mechanical properties during the test period were shown by the disposable electrodes with a large self-adhesive collar.
|
|
| 3. |
- Ask, Per, 1950-
(författare)
-
Oesophageal manometry : design and evaluation of measurement systems
- 1978
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study was to investigate the technical characteristics of oesophageal manometry systems and to improve the performance of these systems.The investigation of the characteristics of oesophageal manometry systems with non-perfused catheters or catheters perfused with a flow generated by a syringe pump did not show properties which fullfilled the requirements for accurate pressure measurements. The bandwidth of the pressure mesurement system was limited by the high compliance of the syringe perfusion pump. The characteristics of perfused systems were improved by the design of a low-compliance perfusion pump. The frequency characteristics of a pressure measurement system utilizing the low-compliance perfusion pump seemed to be determined by the properties of the cathetermanometer system. The frequency content of oesophageal peristaltic pressure was studied by use of a measurement system including the low-compliance perfusion pump. This investigation showed that a bandwidth of about 8 Hz or more is necessary for accurate measurements, which bandwidth can only be obtained with a low-compliance system. In a clinical study a non-perfused system and a system perfused with a syringe pump were compared simultaneously to a system with the low-compliance perfusion pump. The non-perfused system and the system perfused with the syringe pump gave lower peristaltic and sphincter pressure amplitudes than the system with the low-compliance perfusion pump. Since the oesophageal sphincter pressure varies in different radial directions, a pressure transducer has been devised, the mechanical design of which gives an integration of a radial pressure profile. The transducer has a linear static and dynamic transfer function.
|
|
