Objective  

To evaluate the diagnostic accuracy of the Nonin WristOx 3100™ and its software (nVision 5.0) in patients with suspicion of sleep apnea/hypopnea syndrome (SAHS).

Methods  

All participants (168) had the oximetry and polysomnography simultaneously. The two recordings were interpreted blindly. The software calculated: adjusted O₂ desaturation index [ADI]-mean number of O₂ desaturation per hour of total recording analyzed time of ≥ 2%, 3%, 4%, 5%, and 6% (ADI2, 3, 4, 5, and 6) and AT90-accumulated time at SO₂ < 90%. The ADI2, 3, 4, 5, and 6 and the AT90 cutoff points that better discriminated between subjects with or without SAHS arose from the receiver operating characteristic curve analysis. The sensitivity (S), specificity (E), and positive and negative likelihood ratio (LR+, LR−) for the different thresholds for ADI were calculated.

Results  

One hundred and fifty-four patients were included (119 men, mean age 51, median apnea/hypopnea index [AHI] 14, median body mass index [BMI] 28.3 kg/m²). The best cutoff points of ADI were: SAHS = AHI ≥ 5: ADI2 > 19.3 (S 89%, E 94%, LR+ 15.5 LR− 0.11); SAHS =AHI ≥ 10: ADI3 > 10.5 (S 88%, E 94%, LR+ 15 LR− 0.12); SAHS = AHI ≥ 15: ADI3 > 13.4 (S 88%, E 90%, LR+ 8.9, LR− 0.14). AT90 had the lowest diagnosis accuracy. An ADI2 ≤ 12.2 excluded SAHS (AHI ≥ 5 and 10; S 100%, LR− 0) and ADI3 > 4.3 (AHI ≥ 5 and 10) or 32 (AHI ≥ 15) confirmed SAHS (E 100%).

Conclusions  

A negative oximetry defined as ADI2 ≤ 12.2 excluded SAHS defined as AHI ≥ 5 or 10 with a sensitivity and negative likelihood ratio of 100% and 0%, respectively. Furthermore, a positive oximetry defined as an ADI3 > 32 (SAHS = AHI ≥ 15) had a specificity of 100% to confirm the pathology.