Füllekrug B, Beyer R, Reissmann H, Pothmann W
Klinik für Anästhesiologie, Universitäts-Krankenhaus Eppendorf, Hamburg.
Anasthesiol Intensivmed Notfallmed Schmerzther. 2000 Oct;35(10):623-9. doi: 10.1055/s-2000-7363.
We examined the new NasOral-System (NOS; Logomed, Germany), which is designed for a fasten and more complete denitrogenization when compared to the use of a contemporary face-mask. The patient inhales oxygen via a nose mask and exhales via mouthpiece. Nose mask and mouthpiece have built-in one-way valves, resulting in an unidirectional gas flow (nasal-oral).
With approval of the local ethic committee, pre-oxygenation with both the NOS and a face mask (Laerdal) was studied in 50 adult patients. Midazolam 3.75-7.5 mg p.os was given for premedication. The NOS was studied in two different ways: the nose mask fastened by rubberband and with the nose mask held by hand. Prior to induction every patient received every system in a randomised manner. Semi-closed-anaesthetic circle-systems with a fresh-gas-flow of 10 litres/min were used. The FEO2 over 5 min of pre-oxygenation were recorded (AS-3, Datex). Speed and degree of the denitrogenization was documented by an external digital data-acquisition system. Practicability of the systems regarding the anaesthesists (n = 27) and patient comfort were evaluated by means of a standardized postoperative questionnaire.
The hand-held NOS is definitely more effective and reliable than both the NOS fastened by rubber-band and the classical face mask: 80% of the hand-held NOS were able to achieve a FEO2 of > or = 0.8 compared to only 36% of the NOS fixed by rubber-band, face mask: 48%. FEO2 of > or = 0.8 was achieved with 52% of the hand-held NOS in 90 s, a time we consider practical for daily routine, whereas only 10% of the NOS fixed by rubberband and 14% of the face masks accomplished this threshold. A cooperative patient is an important condition when using the NOS: a strong premedication effect, absence of dentures, and patients who can not inspire via nose and expire via mouth involve impairment of the positive effects of the NOS. 21% of the anaesthesists felt disturbed by the NOS. 72% do not believe, that induction of anaesthesia will become more safe with the NOS. For 8 patients, breathing with the NOS was disagreeable (face-mask: 3 patients), 15 were disturbed by the nose part/mouth piece (face-mask: no patient).
An acceptable FEO2 of > or = 0.8 can be achieved only without leakage of both the NOS and the face-mask. Therefore, routine FEO2-monitoring seems highly desirable. Efficiency of the hand-held NOS is much better than with the NOS fastened by rubberband or the face mask. However, even the hand-held NOS cannot guarantee for optimal denitrogenization. Practicability in daily use was poor, because a test of airway patency by manual ventilation prior to relaxation/intubation is not possible with the NOS. Using the device as a help in apnoic oxygenation seems useful.
我们对新型鼻-口系统（NOS；德国Logomed公司）进行了研究，与使用传统面罩相比，该系统旨在实现更快、更完全的去氮。患者通过鼻罩吸入氧气，通过咬嘴呼出。鼻罩和咬嘴均内置单向阀，从而实现单向气流（鼻-口方向）。
经当地伦理委员会批准，对50例成年患者使用NOS和面罩（Laerdal公司）进行预充氧研究。术前口服咪达唑仑3.75 - 7.5 mg进行术前用药。以两种不同方式对NOS进行研究：用橡皮筋固定鼻罩以及用手握住鼻罩。诱导前，每位患者以随机方式使用每种系统。使用新鲜气流为10升/分钟的半封闭式麻醉环路系统。记录预充氧5分钟时的呼气末氧浓度（FEO2；Datex公司AS - 3型）。去氮的速度和程度由外部数字数据采集系统记录。通过标准化的术后问卷评估系统对麻醉医生（n = 27）的实用性以及患者舒适度。
手持NOS肯定比用橡皮筋固定的NOS和传统面罩更有效、更可靠：80%的手持NOS能够使FEO2≥0.8，相比之下，用橡皮筋固定的NOS仅为36%，面罩为48%。52%的手持NOS在90秒内达到FEO2≥0.8，我们认为这个时间在日常工作中是可行的，而用橡皮筋固定的NOS只有10%，面罩只有14%达到这个阈值。使用NOS时，合作的患者是一个重要条件：术前用药效果强、无假牙以及不能经鼻吸气和经口呼气的患者会削弱NOS的积极效果。21%的麻醉医生感觉NOS会造成干扰。72%的人不相信使用NOS会使麻醉诱导更安全。有8例患者使用NOS时呼吸不适（使用面罩为3例患者），15例患者受到鼻罩/咬嘴的干扰（使用面罩无患者出现这种情况）。
只有在NOS和面罩均无泄漏的情况下，才能达到可接受的FEO2≥0.8。因此，常规的FEO2监测似乎非常必要。手持NOS的效率比用橡皮筋固定的NOS或面罩要好得多。然而，即使是手持NOS也不能保证最佳的去氮效果。其日常实用性较差，因为在放松/插管前无法通过手动通气对气道通畅性进行测试。将该设备用于辅助无呼吸氧合似乎是有用的。
