Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Avenida Doutor Eneas de Carvalho Aguiar, 44, 8° Andar, Bloco I, CEP, São Paulo, SP, 05403-900, Brazil.
Biomedical Engineering Laboratory, Escola Politécnica, Universidade de São Paulo, São Paulo, Brazil.
Sleep Breath. 2017 Sep;21(3):631-638. doi: 10.1007/s11325-016-1445-6. Epub 2017 Jan 7.
Negative expiratory pressure (NEP) is a simple technique for the evaluation of upper airway collapsibility in patients with obstructive sleep apnea (OSA). Most studies evaluated NEP using a mouthpiece that may exclude the cephalic portion of the upper airway. We hypothesize that NEP determination is influenced by interface and position.
We evaluated patients with suspected OSA using polysomnography, NEP (-5 cmHO in sitting and supine position with mouthpiece and nasal mask). A subgroup also underwent computed tomography (CT) of the upper airway.
We studied a total of 86 subjects (72 male, age 46 ± 12 yrs, body mass index 30.0 ± 4.4 kg/m, neck circumference 40.0 ± 3.5 cm, AHI 32.9 ± 26.4, range 0.5 to 122.5 events/hour). NEP was influenced by interface and position (p = 0.007), and upper airway was more collapsible with mouthpiece than with nasal mask in sitting position (p = 0.001). Position influenced NEP and was worse in supine only when evaluated by nasal mask. Expiratory resistance (R ) at 0.2 s during NEP was significantly higher and independent of position with mouthpiece than with nasal mask (20.7 versus 8.6 cmHO/L s, respectively, p = 0.018). NEP evaluated with nasal mask in supine position and with mouthpiece in sitting position, but not when evaluated with mouthpiece in supine position, were correlated with upper airway anatomical measurements including tongue dimensions and pharyngeal length.
Interface and position influence NEP. NEP evaluated with nasal mask in supine position may convey more relevant information for patients under investigation for OSA than when evaluated with mouthpiece.
负呼气压力（NEP）是评估阻塞性睡眠呼吸暂停（OSA）患者上气道 collapsibility 的简单技术。大多数研究使用可能排除上气道头侧部分的口件评估 NEP。我们假设 NEP 的测定受接口和位置的影响。
我们使用多导睡眠图评估疑似 OSA 的患者，NEP（坐位和仰卧位时用口件和鼻罩分别为-5 cmHO）。亚组还接受了上气道计算机断层扫描（CT）。
我们共研究了 86 名患者（72 名男性，年龄 46±12 岁，体重指数 30.0±4.4 kg/m，颈围 40.0±3.5 cm，AHI 32.9±26.4，范围 0.5 至 122.5 事件/小时）。接口和位置影响 NEP（p=0.007），并且在上气道中，坐位时用口件比用鼻罩更易塌陷（p=0.001）。仅当用鼻罩评估时，仰卧位时位置会影响 NEP，并且更差。在用口件和鼻罩评估时，NEP 期间 0.2 秒的呼气阻力（R）均显著高于且独立于位置（分别为 20.7 和 8.6 cmHO/L/s，p=0.018）。用鼻罩在仰卧位和用口件在坐位评估时的 NEP，但不用口件在仰卧位评估时的 NEP，与上气道解剖学测量值相关，包括舌尺寸和咽长度。
接口和位置影响 NEP。用鼻罩在仰卧位评估 NEP 可能比用口件评估时为正在接受 OSA 调查的患者提供更相关的信息。
