夜间血氧饱和度监测对睡眠呼吸暂停综合征的诊断价值

目的探讨夜间动态血氧饱和度（SaO2）监测对睡眠呼吸暂停综合征（SAS）患者的诊断价值。方法对比174例打鼾者的动态SaO2及多导生理仪睡眠呼吸监测结果，并根据睡眠呼吸暂停低通气指数（AHI）将其中的100例受试者分为非SAS组（AHI＜5）工例、轻度SAS（AHI5～19）26例、中度SAS（AHI20～39）25例、重度SAS（AHI≥40）23例四组，测定其持续气道正压通气（CPAP）治疗前后的动态SaO2变化。结果每小时氧饱和度下降≥4％的次数（DI4即氧减饱和度指数）与AHI的相关性好（r＝0．91，P＜0．001），能够较好地反映SAS患者睡眠呼吸紊乱的频度，对AHI≥5患者，DI4≥5的敏感性达94％以上，能够检出绝大多数的SAS患者；若以DI4≥15为标准，可以准确诊断98％以上的SAS患者，且两项指标都不会漏诊AHI≥20的患者。治疗前各组两两之间及治疗前后的DI4、氧饱和度≤90％的时间占总监测时间的百分比（SIT90）均有显著差异（P＜0．01）。结论选用适当的DI4作为标准，对初步筛选或准确判断SAS患者具有一定价值；DI4及SIT90能够较好地反映SAS患者夜间缺氧的程度，可作为综合判断SAS患者病情严重程度的指标，对SAS治疗效果的判定也有指导意义。

Utility of nocturnal oximetry for case finding in patients with suspected sleep apnea syndrome

OBJECTIVE: Pulse oximeter is a useful screening device for SAS. We studied whether measurement of SaO2 could identify patients with SAS and evaluate the severity of SAS. METHODS: 174 snorers were assessed clinically and then underwent formal PSG and oximetry test at the same time. From the oximetry data, the percentage of time spent at SaO2 below 90% (SIT90%), waking SaO2(H SaO2%), the lowest SaO2(L SaO2%) during sleep, the mean SaO2(M SaO2%) and the number of oxygen desaturation > or = 4% per hour (DI4) were calculated. We also divided 100 cases among them into four groups by AHI, which were G0(AHI < 5), G1(AHI 5-19), G2(AHI 20-39), G3(AHI > or = 40), and evaluated whether the SIT90, ISaO2, MSaO2 and DI4 are different among the four groups. RESULTS: There was an statistically significant correlation (r = 0.91 P < 0.001) between DI4 and AHI. DI4 > or = 5 per hour identified patients with AHI > 5 with a sensitivity of 94%; DI4 > or = 15 per hour identified patients with AHI > 5 with a specificity of 98%, and for patients with AHI > or = 20, the sensitivity was 100%. The SIT90 and DI4 were significantly different among the four groups (P < 0.01). CONCLUSIONS: Oximetry with DI4 < 5 practically excludes clinically significant SAS, and DI4 > or = 15 identified almost all of them. SIT90 and DI4 could be used as parameters in evaluating the severity of SAS.