Laser Doppler Monitoring Research Articles

Laser doppler monitoring of replants using a small prism probe

Eighteen patients admitted to Duke University Medical Center for upper limb replantation or revascularization were studied. A small laser Doppler flow prism probe and a cutaneous temperature probe were attached to the distal pulp of replanted digits. Measurements were recorded hourly for the first 3 postoperative days. In the successful cases, the mean laser Doppler flow measurement was 1.76 units (lower 97% confidence limit 0.5 units) and the mean temperature was 34.1 degrees C (lower 97% confidence limit 32 degrees C). In 4 patients with vascular compromise, the laser Doppler flow correctly identified the problem. The reduced size of the new laser Doppler probe makes monitoring of distal pulp flow technically easier while maintaining accuracy.

Routine use of laser Doppler flowmetry for monitoring autologous tissue transplants.

This is a report of a prospective study in which 41 consecutive autologous tissue transplants were monitored using the Laserflo BPM model 403 laser Doppler monitor (TSI Inc., St. Paul, MN). Flaps were monitored both intraoperatively and postoperatively, and clinical flap monitoring was compared with laser Doppler monitoring. Twenty-nine flaps had no problems as indicated by clinical or Doppler measurement. Twelve flaps underwent 13 reexplorations; one flap was explored twice. Five venous and five arterial anastomoses were corrected, with complete survival of the flaps. Three hematomas were evacuated. Two of these flaps failed. There were no instances where the laser Doppler indicated a problem with flap viability that subsequently did not merit reexploration. There were no instances of flap failure undetected by the laser Doppler. In comparison to the clinical monitoring, laser Doppler monitoring was more rapid and more precise in identifying problems with the flap. The use of this monitor has improved our salvage rate for flap reexploration from 50 to 85% and has provided a more objective standard for both nurses and physicians to evaluate flaps in the perioperative period.

Laser Doppler monitoring of microcirculatory changes in acute burn wounds.

Because burns are dynamic wounds that can change in apparent depth during the first 72 hours, we asked whether measuring changes in cutaneous blood flow might help predict the ultimate fate of burns that were not obviously shallow or deep. A laser Doppler flowmeter was used to study cutaneous perfusion for at least 72 hours in partial-thickness wounds on patients with burns of less than 15% TBSA and in experimental wounds of similar size on rats. Clinical wounds that healed without grafting consistently showed elevated perfusion levels which increased further within 72 hours, whereas wounds eventually requiring grafting experienced lower perfusion levels with no obvious pattern of increase. Differences between average flow levels for healing and nonhealing burns were statistically significant throughout the study period. Perfusion levels in experimental wounds were stratified according to burn severity, with shallower wounds showing a pattern of increase similar to the clinical wounds.