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Fluorescein and acidosis. Implications for flap perfusion studies
R M Odland1, D V Poole, G M Lessard
1Department of Surgery, Loma Linda University School of Medicine, CA.
Archives of Otolaryngology--Head & Neck Surgery
|July 11, 1992
Summary
Acidosis reduces fluorescein fluorescence, explaining why the visual fluorescein technique underpredicts skin flap survival. This finding is crucial for accurate microcirculation studies.
Area of Science:
- Biomedical Engineering
- Surgical Research
- Fluorescence Spectroscopy
Background:
- The visual fluorescein technique is used to assess skin flap survival.
- This technique currently underpredicts flap viability in the initial 24 hours post-surgery.
- The underlying cause for this underprediction remains unclear.
Purpose of the Study:
- To investigate the hypothesis that tissue acidosis quenches fluorescein fluorescence.
- To determine the quantitative effect of acidosis on sodium fluorescein's fluorescence intensity in vitro.
Main Methods:
- Sodium fluorescein solutions at two concentrations (10^-5 g/mL and 10^-7 g/mL) were prepared.
- Buffered solutions with varying pH levels were used to simulate acidosis.
- A spectrophotometer measured fluorescence intensity across different pH conditions.
Main Results:
- Fluorescence intensity significantly decreased with decreasing pH.
- At 10^-5 g/mL, fluorescence dropped by 26% from pH 7.5 to 7.0 and 51% from pH 7.5 to 6.5.
- At 10^-7 g/mL, a 43% decrease in fluorescence was observed between pH 7.5 and 6.5.
Conclusions:
- The in vitro study confirms that acidosis quenches fluorescein fluorescence.
- This pH-dependent quenching effect must be considered when interpreting fluorescein-based skin flap viability studies.
- Findings necessitate re-evaluation of current fluorescein techniques in microcirculation research.