Farré R, Peslin R, Montserrat J M, Rotger M, Navajas D
Lab. Biofísica i Bioenginyeria, Facultat de Medicina, Institute d'Investigacions Biomèdiques Agusti Pi i Sunyer, Universitat de Barcelona, Spain.
Am J Respir Crit Care Med. 1998 Jun;157(6 Pt 1):1855-63. doi: 10.1164/ajrccm.157.6.9710056.
Airway obstruction in patients with sleep apnea-hypopnea syndrome (SAHS) is due to increased critical pressure (Pcrit) of the upper airway. The ideal nasal pressure (Pn) to maintain airway patency should consist of the constant term to account for Pcrit and a term (Rn . V) proportional to flow (V) to account for the dynamic pressure drop through nasal resistance (R n). Continuous positive airway pressure (CPAP) applied to avoid flow limitation results in a Pn greater than required over most of the breathing cycle. The aim was to assess a flow-dependent positive airway pressure (FDPAP) based on adapting Pn to the instantaneous flow: Pn = P0 + k . V. FDPAP was tested on collapsible airway models and its applicability was assessed in nine patients with SAHS during sleep. In models, FDPAP prevented flow limitation with lower mean P n and work of breathing than CPAP. In patients FDPAP allowed the patients to breathe normally with a mean Pn (6.6 +/- 1.2 cm H2O) systematically and significantly (p < 0.05, paired t test) lower than when applying CPAP (9.1 +/- 1.2 cm H2O). The results found in models and in patients suggest that adapting the applied nasal pressure to the instantaneous breathing flow may be of potential practical interest in SAHS.
睡眠呼吸暂停低通气综合征（SAHS）患者的气道阻塞是由于上气道临界压力（Pcrit）升高所致。维持气道通畅的理想鼻压力（Pn）应包括用于解释Pcrit的常数项以及与流量（V）成正比的项（Rn.V），以解释通过鼻阻力（Rn）产生的动态压力降。为避免气流受限而施加的持续气道正压通气（CPAP）在大部分呼吸周期中导致Pn大于所需值。目的是评估一种基于使Pn适应瞬时流量的流量依赖性气道正压通气（FDPAP）：Pn = P0 + k.V。在可塌陷气道模型上测试了FDPAP，并在9名SAHS患者睡眠期间评估了其适用性。在模型中，与CPAP相比，FDPAP以更低的平均Pn和呼吸功防止了气流受限。在患者中，FDPAP使患者能够正常呼吸，其平均Pn（6.6±1.2 cm H2O）系统性且显著（p < 0.05，配对t检验）低于应用CPAP时（9.1±1.2 cm H2O）。在模型和患者中发现的结果表明，使所施加的鼻压力适应瞬时呼吸流量在SAHS中可能具有潜在的实际意义。
