Comparison between unilateral PNIF and rhinomanometry in the evaluation of nasal cycle.

BACKGROUND: Human unilateral nasal airflow shows spontaneous changes over a period of hours due to the alternating congestion and decongestion of the venous sinuses within the nasal turbinates and nasal septum. The aim of the present study was to compare PNIF and unilateral PNIF with nasal resistances measured by means of AAR in the evaluation of the nasal cycle. METHODS: PNIF, unilateral PNIF and AAR measurements were randomly performed in 20 non-smokers, non-asthmatic volunteers, with a SNOT 22 score lower than 1. Nasal measurements were done four times in a single day at 08.30, 11.00, 13.30 and 16.00. The correlation between PNIF, unilateral PNIF and nasal resistances was studied. The pattern of nasal airflow for each subject was also analyzed. RESULTS: A significant negative correlation between PNIF-lPNIF-rPNIF and respectively AAR-lAAR-rAAR was found. Only 1 subject did not show nasal cycle, while all the rest were equally distributed between a reciprocal pattern of the nasal cycle, or an in-phase changes of the nasal cycle, both at PNIF and AAR. CONCLUSIONS: Nasal cycle can be easily assessed by means of PNIF. In fact, AAR and PNIF showed a reasonable correlation in the measurement of nasal cycle, although PNIF offered a lower variability. Reciprocal and in-phase patterns of the nasal cycle were equally distributed in our population.

The role of single-channel nasal airflow pressure transducer in the diagnosis of OSA in the sleep laboratory.

RATIONALE: Obstructive sleep apnea (OSA) is a common but underdiagnosed disorder. There is a need for validated simpler modalities such as single-channel monitors to assist diagnosis of OSA. STUDY OBJECTIVES: To assess data sufficiency, agreement, and diagnostic accuracy of nasal airflow measured by a single-channel pressure transducer device (Flow Wizard, DiagnoseIT, Sydney, Australia) compared to attended full polysomnography (PSG) on the same night for OSA diagnosis. DESIGN: Cross-sectional study. SETTING: Laboratory. PARTICIPANTS: Subjects with possible OSA referred to the sleep laboratory for PSG were eligible. METHODS: Nasal airflow was measured by a pressure transducer in the laboratory concurrently with PSG. RESULTS: Of 226 eligible subjects who consented, 221 (97.8%; 151 males, 70 females) completed the protocol. With nasal airflow measurement, 5.3% of subjects had insufficient data, compared with 2.2% on PSG. The mean difference between PSG AHI and NF RDI was -6.2 events/h with limits of agreement (+/- 2 standard deviation [SD]) of 17.0 events/hr. The accuracy of the Flow Wizard for diagnosing severe OSA (PSG AHI > 30) was very good (area under the ROC curve [AUC] 0.96; 95% confidence interval [CI] 0.92 to 0.99) and for diagnosing OSA (PSG AHI > 5) was good (AUC, 0.84; 95% CI, 0.77 to 0.90). There was no difference in the rate of data insufficiency and accuracy between males and females. CONCLUSION: Nasal flow measured by a nasal pressure transducer has a low rate of data insufficiency, good agreement, and high accuracy compared to PSG for diagnosing OSA in the monitored sleep laboratory setting.