Pulse oximetry from the nasal septum.

STUDY OBJECTIVE

To evaluate the accuracy of the nasal septum site for pulse oximetry measurement of arterial oxyhemoglobin saturation (SpO2) in hypothermic patients.

DESIGN

Prospective study.

SETTING

Operating theater of a public hospital.

PATIENTS

Fourteen hypothermic (temperature 34.6 degrees C to 36 degrees C) patients (eight males and six females) undergoing a major surgical abdominal procedure.

INTERVENTIONS

Fifty estimations of SpO2 were simultaneously made by a flex sensor probe applied at the nasal septum site and by a finger sensor probe using a pulse oximeter. The results were compared with arterial oxygen saturation (SaO2) as measured by arterial blood gas sampling.

MEASUREMENTS AND MAIN RESULTS

In 18% of the estimations, the finger probe produced unmeasurable results. The nasal septum probe did not produce any unmeasurable results (p = 0.0055). In the remaining 41 estimations, a comparison of the measurements from the nasal septum versus the controls showed a mean difference of 0.15 and a limit of agreement of -0.106 to +0.398. A comparison difference of 2.27 and a limit of agreement of 1.986 to 2.551.

CONCLUSION

Monitoring SpO2 at the nasal septum site is more reliable than monitoring it at the finger site in hypothermic patients.