Frühzeitige Erkennung arterieller und venöser Gefäßkomplikationen bei Lappenplastiken durch die Kombination der digitalen Photoplethysmographie (=Lichtreflexionsrheographie) mit dem Lagewechseltest

The transplantation of flaps is a surgical technique which is often used for reconstruction of defects in soft tissues. A vascular complication is one of the main problems that arises in the postoperative period. The present thesis investigates the applicability of a non-invasive method, the digital photoplethysmography, for the detection of postoperative vascular complications in transplanted dermal flaps. This digital photoplethysmography is combined with standardized position changes of the test patient. These position changes simulate characterisitic fluctuations in blood circulation, which are typical for both uncomplicated wound healing and that delayed by arterial and venous obstructions. Fifteen test persons, nine men and six women, participated in the examination. For these patients, a transplantation of a free or pedicle flap to one of the areas, lower leg, arm, shoulder, neck or chin was impending. Each of the test persons participated in eleven examinations over a period of 21 days. For three of the test persons a vascular obstruction was clinically obvious, while twelve cases could be considered free of complications. For two out of the three cases with an obvious complication, the study methodology was not able to detect the obstruction. For three out the twelve cases without vascular problems, the method incorrectly suggested a complication. Several reasons for the failure of the measurements can be identified. For one, the fluctuations in blood circulation strongly vary with respect to the location of the transplant. While the position changes induce strong fluctuations in the lower leg and the chin/neck area, the fluctuations in the chest area and the axilla are too small to be detected by the digital photoplethysmography. Second, a heterogeneous perfusion in the capillary bed, especially in the postischemic period, may temporarily impede the necessary volumetric changes. Moreover, the probe has to be reattached for each measurement. This results in a slight relocation of the probe which renders a direct comparison of the measured data very difficult. Finally, the approach used in the present thesis suffers from technical problems which it has in common with other probe-based methods. In particular, the probe is typically far smaller than the surface of the flap, and therefore it is not capable of capturing the properties of the entire flap and only provides information on a small area of the flap. The choice of this area is left to the investigator and therefore turns out to be more or less arbitrary. By definition a method for acute monitoring must allow to detect a vascular obstruction by a single non-invasive measurement. For the reasons listed above, the digital photoplethysmography does not qualify for acute monitoring. Most importantly, however, the method strongly depends on the subjective interpretation of the user. Consequently, it cannot be considered objective and reliable.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Mönnigmann, Susanne

Contributors dc:contributor

• Pallua, Norbert

• info:eu-repo/classification/ddc/610
• Medizin
• digital
• Photoplethysmographie
• Lagewechseltest
• Lappenplastik

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123554%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:61946