Barchfeld T, Schönhofer B, Wenzel M, Köhler D
Krankenhaus Kloster Grafschaft, Zentrum für Pneumologie, Schlaf- und Beatmungsmedizin, Schmallenberg Grafschaft.
Pneumologie. 1997 Sep;51(9):931-5.
In contrast to the obstructive sleep apnoea syndrome (OSA) the obesity-hypoventilation syndrome (OHS) is characterised by persistent hypercapnia during the day and predominant hypoventilation during sleep. In this study we wanted to know whether work of breathing (WOB) in a sitting and supine position separates both groups.
OSA population: 20 men, 50.5 +/- 9.2 years, Body Mass Index (BMI: 54.1 +/- 6.9 kg/m2, pO2: 65.6 +/- 6.6 mmHg, pCO2: 40.6 +/- 3.1 mmHg, OHS-group: 14 patients, 13 men age: 53.1 +/- 9.3 years, BMI: 53.1 +/- 9.3 kg/m2, pO2: 51.8 +/- 10.5 mmHg, pCO2: 53.8 +/- 9.2 mmHg. The control group consisted of 10 normal weighted subjects. The intrathoracic pressures were assessed by an oesophageal catheter; at the same time, the minute ventilation (VE) and the breathing frequency (fb) were measured via a pneumotachygraph. The area under the pressure-volume loop was correlated to WOB. After reaching steady state VE, fb, and WOB were determined in sitting and supine position.
In the OSA-group the apnoea index (AI) was 48.6 +/- 17.7/h and the respiratory disturbance index (RDI) was 66.3 +/- 19.4/h. The forced expiratory volume (FEV1) was 77.3 +/- 23% pred. and the vital capacity (VC) was 76.3 +/- 18.6% pred.; 7 out of 20 patients suffered from chronic bronchitis. In the OHS-group the AI was 21.5 +/- 19/h and the RDI 44.3 +/- 28.2/h. The majority of OHS patients had an airway obstruction (FEV1: 55.8 +/- 17.5% pred., VC: 58.8 +/- 12.8% pred.); 12 out of 14 patients suffered from chronic bronchitis. Compared to the OSA population WOB in the OHS group was significantly higher both in the sitting (0.67 +/- 0.28 J/I versus 1.04 +/- 0.32 J/I, p < 0.001) and supine positions (1.23 +/- 0.25 J/I versus 1.91 +/- 0.43 J/I, p < 0.001). Compared to the sitting position VE and fb did not change significantly in both groups lying supine.
Compared to the OSA group at the same BMI the WOB of the OHS population was significantly increased in the sitting and supine position. The main reason for these findings may be the increased airway obstruction due to chronic bronchitis. Both populations did not change the breathing patterns during the different positions.
与阻塞性睡眠呼吸暂停综合征（OSA）不同，肥胖低通气综合征（OHS）的特征是白天持续高碳酸血症以及睡眠期间主要的通气不足。在本研究中，我们想了解坐姿和仰卧位时的呼吸功（WOB）是否能区分这两组。
OSA组：20名男性，年龄50.5±9.2岁，体重指数（BMI）：54.1±6.9kg/m²，动脉血氧分压（pO₂）：65.6±6.6mmHg，动脉血二氧化碳分压（pCO₂）：40.6±3.1mmHg；OHS组：14名患者，13名男性，年龄53.1±9.3岁，BMI：53.1±9.3kg/m²，pO₂：51.8±10.5mmHg，pCO₂：53.8±9.2mmHg。对照组由10名体重正常的受试者组成。通过食管导管评估胸内压；同时，通过呼吸流速仪测量分钟通气量（VE）和呼吸频率（fb）。压力-容积环下的面积与呼吸功相关。在达到稳定状态的VE、fb和WOB后，分别在坐姿和仰卧位进行测定。
在OSA组中，呼吸暂停指数（AI）为48.6±17.7次/小时，呼吸紊乱指数（RDI）为66.3±19.4次/小时。用力呼气量（FEV₁）为预计值的77.3±23%，肺活量（VC）为预计值的76.3±18.6%；20名患者中有7名患有慢性支气管炎。在OHS组中，AI为21.5±19次/小时，RDI为44.3±28.2次/小时。大多数OHS患者存在气道阻塞（FEV₁：预计值的55.8±17.5%，VC：预计值的58.8±12.8%）；14名患者中有12名患有慢性支气管炎。与OSA组相比，OHS组在坐姿（0.67±0.28J/I对1.04±0.32J/I，p<0.001）和仰卧位（1.23±0.25J/I对1.91±0.43J/I，p<0.001）时的呼吸功均显著更高。与坐姿相比，两组仰卧位时VE和fb均无显著变化。
与相同BMI的OSA组相比，OHS组在坐姿和仰卧位时的呼吸功均显著增加。这些发现的主要原因可能是慢性支气管炎导致的气道阻塞增加。两组在不同体位时均未改变呼吸模式。
