Sridhar M K, Carter R, Lean M E, Banham S W
Department of Respiratory Medicine, Glasgow Royal Infirmary, UK.
Thorax. 1994 Aug;49(8):781-5. doi: 10.1136/thx.49.8.781.
Weight loss is a well recognised feature of patients with emphysematous chronic obstructive pulmonary disease (COPD). It has been suggested that this weight loss could be due to a hypermetabolic state resulting from the increased oxygen cost of breathing (OCB). To clarify the relation between resting energy expenditure (REE), nutritional state, and OCB these indices were measured in patients with respiratory impairment and an increased OCB due to COPD, scoliosis, and thoracoplasty.
Eighteen patients (six COPD, six scoliosis, six thoracoplasty) of mean (SD) age 59.9 (8.6) years (8M, 10F) and six controls (45.5 (9.9) years; 2M, 4F) were studied. OCB was estimated by the addition of dead space to the breathing circuit and REE was measured by indirect calorimetry using a ventilated canopy system. Height, arm span, weight, triceps skin fold thickness (TSF), mid-arm muscle circumference (MAMC), forced expiratory volume in one second (FEV1), and vital capacity (VC) were measured in all study subjects.
OCB was elevated in all patient groups (mean 7.0 ml/l) compared with controls (1.9 ml/l). All patients with COPD, four with scoliosis, three with thoracoplasty, and none of the controls were < 90% ideal body weight. Mean (SD) measured REE as % predicted (Harris-Benedict equation) was 103.8 (7.6) in patients with COPD, 105.5 (10.9) in those with scoliosis, 106.3 (6.9) in the thoracoplasty patients, and 103.3 (3.4) in controls. One patient with COPD, two with scoliosis, two with thoracoplasty, but no controls were hypermetabolic (REE > 110% predicted). In all groups there was a negative relation between OCB and lung function (OCB v FEV1 r = -0.83 in COPD, -0.62 in scoliosis, -0.67 in thoracoplasty, and -0.76 in controls). There was no correlation between REE and OCB or MAMC.
In patients with respiratory disease OCB (augmented ventilation) is related to lung function but not to REE. This is evidence against the hypothesis that hypermetabolism due to increased oxygen cost of breathing at rest is the sole or major cause of malnutrition in patients with lung disease.
体重减轻是肺气肿型慢性阻塞性肺疾病（COPD）患者的一个公认特征。有人提出，这种体重减轻可能是由于呼吸氧气成本（OCB）增加导致的高代谢状态所致。为了阐明静息能量消耗（REE）、营养状态和OCB之间的关系，对因COPD、脊柱侧弯和胸廓成形术导致呼吸功能受损且OCB增加的患者进行了这些指标的测量。
研究了18例患者（6例COPD、6例脊柱侧弯、6例胸廓成形术），平均（标准差）年龄59.9（8.6）岁（8例男性，10例女性），以及6例对照者（45.5（9.9）岁；2例男性，4例女性）。通过在呼吸回路中增加死腔来估计OCB，使用通气面罩系统通过间接测热法测量REE。对所有研究对象测量身高、臂展、体重、肱三头肌皮褶厚度（TSF）、上臂中部肌肉周长（MAMC）、一秒用力呼气量（FEV1）和肺活量（VC）。
与对照组（1.9 ml/l）相比，所有患者组的OCB均升高（平均7.0 ml/l）。所有COPD患者、4例脊柱侧弯患者、3例胸廓成形术患者且无对照者的体重低于理想体重的90%。以预测值（Harris-Benedict方程）的百分比表示的平均（标准差）测量REE在COPD患者中为103.8（7.6），脊柱侧弯患者中为105.5（10.9），胸廓成形术患者中为106.3（6.9），对照组中为103.3（3.4）。1例COPD患者、2例脊柱侧弯患者、2例胸廓成形术患者存在高代谢（REE >预测值的110%），但对照者中无高代谢者。在所有组中，OCB与肺功能之间均呈负相关（在COPD中OCB与FEV1的r = -0.83，脊柱侧弯中为-0.62，胸廓成形术中为-0.67，对照组中为-0.76）。REE与OCB或MAMC之间无相关性。
在呼吸系统疾病患者中，OCB（增强通气）与肺功能相关，但与REE无关。这一证据反驳了静息时呼吸氧气成本增加导致的高代谢是肺部疾病患者营养不良的唯一或主要原因这一假说。
