Fluorescence optical fibre sensor provides accurate continuous oxygen detection in rabbit model with acute lung injury

Background and objective:  Continuous monitoring of PaO2 in seriously ill patients is an important aspect of clinical management, especially for patients with acute lung injury (ALI) or acute respiratory distress syndrome. We have developed a fibreoptic sensor to detect PaO2in vivo based on fluorescence quenching technology. In this study we evaluated the sensitivity of this sensor in monitoring PaO2 in a rabbit model with ALI. Methods:  The oxygen sensor is a membrane made of Ru(dpp)3(PF6)2, poly-2-methacryloyloxyethyl phosphorylcholine and butylmethacylate copolymer p-(MPC-co-BMA) located at the tip of the optical fibre. The sensor was inserted into the carotid artery of the animals and monitored PaO2 continuously. Oleic acid was intravenously injected to induce lung injury. Simultaneous comparisons were made between PaO2 measured by blood gas analysis and PaO2 measured by the fibreoptic sensor, both before and after lung injury. Results:  The fluorescence intensity decreased gradually following ALI, reflecting increasing hypoxia. Correlation coefficients between measurements by the oxygen sensor and by the blood gas analysis were 0.995 ± 0.003, 0.994 ± 0.002 and 0.993 ± 0.005 (P < 0.05) for control animals, animals with ALI and animals with electrolyte disturbance, respectively. The bias and precision for normal animals was −1.5 ± 10.8 mm Hg, for animals with ALI was −1.2 ± 11.2 mm Hg and for animals with electrolyte disturbance was −1.4 ± 9.2 mm Hg. Conclusions:  The oxygen sensor showed high accuracy and stability for continuous monitoring of PaO2 in normal animals, in animals with ALI and in animals with electrolyte disturbance, suggesting that it may be clinically useful in the continuous measurement of oxygen partial pressure.