Sham continuous positive airway pressure for placebo-controlled studies in sleep apnoea
Sham continuous positive airway pressure for placebo-controlled studies in sleep apnoea
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DOI：
10.1016/s0140-6736(99)01056-9
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发表时间：
1999-04-03
期刊：
影响因子：
168.9
通讯作者：
Navajas, D
中科院分区：
文献类型：
--
作者：
Farré, R;Hernández, L;Navajas, D
睡眠呼吸暂停/低通气综合征常用鼻持续气道正压通气（CPAP）治疗。由于患者不受相同的仪器限制，CPAP的疗效已与不符合安慰剂要求的程序进行了比较评估。2,3由于缺乏安慰剂对照研究以及CPAP的成本，CPAP的有效性受到质疑。4,5我们设计了一种假CPAP方法用于睡眠呼吸暂停的安慰剂对照研究。CPAP设备包括泵、导管和带呼气口的鼻罩（图a）。CPAP是由呼气口阻力上的压降产生的。为了实现假CPAP（图B），呼气口的气流阻力几乎通过增加其面积而消除，从而实际上消除了鼻压，并且在CPAP装置和管道之间连接了与原始呼气口相同的孔板电阻，以便使鼓风机具有与真CPAP相同的气流阻力。呼吸机的工作噪音和通过呼出气口的气流保持不变，这对CPAP安慰剂至关重要。我们测试了一台CPAP设备（PV100，瑞典Breas Medica）。呼气口直径从4毫米增加到10毫米，并在泵和油管之间放置一个直径4毫米的孔型电阻。对于真CPAP和假CPAP系统，通过呼气口的流量和操作噪声是相同的（分别在10%和1 dBA以内）。对8例清醒睡眠呼吸暂停患者的初步研究表明，假性鼻CPAP实际为0.4 (SD 0.1) cm H2O，避免了再呼吸（在面罩上测量的血氧饱和度[SaO2]和尾潮CO2、平均温度和湿度与CPAP在8 cm H2O和假性CPAP相同）。进行了一项通宵多导睡眠图研究，以验证假CPAP系统是否改变了I、II期患者的睡眠（效率、觉醒/微觉醒、夜间时间百分比）
The sleep apnoea/hypopnoea syndrome is commonly treated with nasal continuous positive airway pressure (CPAP). 1 The efficacy of CPAP has been assessed in comparison with procedures which do not meet the requirements of a placebo because the patient is not subjected to the same instrumental constraints. 2, 3 Given the lack of placebo-controlled studies together with the costs of CPAP, the usefulness of CPAP has been called into question. 4, 5 We designed a method of sham CPAP for placebo-controlled studies in sleep apnoea. CPAP equipment includes a pump, tubing, and a nasal mask with an exhalation port (figure, A). CPAP is generated by the pressure drop across the resistance of the exhalation port. To implement sham CPAP (figure, B), airflow resistance of the exhalation port is almost eliminated by increasing its area, thereby virtually cancelling nasal pressure, and an orifice resistor identical to the original exhalation port is connected between the CPAP unit and the tubing in order to load the blower with the same airflow resistance as in true CPAP. The ventilator operating noise and the airflow through the exhalation port remain unchanged, which are crucial to a CPAP placebo. We tested a CPAP device (PV100, Breas Medica, Sweden). The exhalation port diameter was increased from 4 to 10 mm and a 4 mm diameter orfice-type resistor was placed between the pump and the tubing. Flow through the exhalation port and operating noise were the same (within 10% and 1 dBA, respectively) for the true CPAP and the sham CPAP systems. A preliminary study in eight awake patients with sleep apnoea showed that actual nasal sham CPAP was 0· 4 (SD 0· 1) cm H2O and that rebreathing was avoided (oxygen saturation [SaO2] and end-tidal CO2, mean temperature, and humidity measured at the mask were the same with CPAP at 8 cm H2O and with sham CPAP). An all-night polysomnographic study was carried out to verify whether or not the sham CPAP system modified the patient’s sleep(efficiency; arousals/microarousals; percent night time in stages I, II