肥胖症患者术后镇静-肌松状态下的全呼吸系统、肺及胸壁力学

Total respiratory system, lung, and chest wall mechanics in sedated-paralyzed postoperative morbidly obese patients.

作者信息

Pelosi P, Croci M, Ravagnan I, Vicardi P, Gattinoni L

机构信息

Istituto di Anestesia e Rianimazione, Universita' di Milano, Milan, Italy.

出版信息

Chest. 1996 Jan;109(1):144-51. doi: 10.1378/chest.109.1.144.

DOI:10.1378/chest.109.1.144

PMID:8549177

Abstract

OBJECTIVE

To study the relative contribution of the lung and the chest wall on the total respiratory system mechanics, gas exchange, and work of breathing in sedated-paralyzed normal subjects and morbidly obese patients, in the postoperative period.

SETTING

Policlinico Hospital, University of Milan, Italy.

METHODS

In ten normal subjects (normal) and ten morbidly obese patients (obese), we partitioned the total respiratory mechanics (rs) into its lung (L) and chest wall (w) components using the esophageal balloon technique together with airway occlusion technique, during constant flow inflation. We measured, after abdominal surgery, static respiratory system compliance (Cst,rs), lung compliance (Cst,L), chest wall compliance (Cst,w), total lung (Rmax,L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). DR,L represents the component due to viscoelastic phenomena of the lung tissue and time constant inequalities (pendelluft). Functional residual capacity (FRC) was measured by helium dilution technique.

RESULTS

We found that morbidly obese patients compared with normal subjects are characterized by the following: (1) reduced Cst,rs (p < 0.01), due to lower Cst,L (55.3 +/- 15.3 mL x cm H2O-1 vs 106.6 +/- 31.7 mL x cm H2O-1; p < 0.01) and Cst,w (112.4 +/- 47.4 mL x cm H2O-1 vs 190.7 +/- 45.1 mL x cm H2O-1; p < 0.01); (2) increased Rmin,L (4.7 +/- 3.1 mL x cm H2O x L-1 x s; vs 1.0 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01) and DR,L (4.9 +/- 2.6 mL x cm H2O x L-1 x s; vs 1.5 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01); (3) reduced FRC (0.665 +/- 0.191 L vs 1.691 +/- 0.325 L; p < 0.01); (4) increased work performed to inflate both the lung (0.91 +/- 0.25 J/L vs 0.34 +/- 0.08 J/L; p < 0.01) and the chest wall (0.39 +/- 0.13 J/L vs 0.18 +/- 0.04 J/L; p < 0.01); and (5) a reduced pulmonary oxygenation index (PaO2/PAO2 ratio).

CONCLUSION

Sedated-paralyzed morbidly obese patients, compared with normal subjects, are characterized by marked derangements in lung and chest wall mechanics and reduced lung volume after abdominal surgery. These alterations may account for impaired arterial oxygenation in the postoperative period.

摘要

目的

研究在术后阶段，肺和胸壁对镇静 - 麻痹的正常受试者及病态肥胖患者的全呼吸系统力学、气体交换和呼吸功的相对贡献。

设置

意大利米兰大学 Policlinico 医院。

方法

在 10 名正常受试者（正常组）和 10 名病态肥胖患者（肥胖组）中，我们在持续气流充气过程中，采用食管气囊技术联合气道阻断技术，将全呼吸力学（rs）分为肺（L）和胸壁（w）两部分。在腹部手术后，我们测量了静态呼吸系统顺应性（Cst,rs）、肺顺应性（Cst,L）、胸壁顺应性（Cst,w）、全肺阻力（Rmax,L）和胸壁阻力（Rmax,w）。Rmax,L 包括气道阻力（Rmin,L）和“额外”肺阻力（DR,L）。DR,L 代表由于肺组织粘弹性现象和时间常数不均一性（pendelluft）导致的部分。功能残气量（FRC）通过氦稀释技术测量。

结果

我们发现，与正常受试者相比，病态肥胖患者具有以下特征：（1）Cst,rs 降低（p < 0.01），这是由于 Cst,L 较低（55.3 ± 15.3 mL·cmH₂O⁻¹ 对比 106.6 ± 31.7 mL·cmH₂O⁻¹；p < 0.01）以及 Cst,w 较低（112.4 ± 47.4 mL·cmH₂O⁻¹ 对比 190.7 ± 45.1 mL·cmH₂O⁻¹；p < 0.01）；（2）Rmin,L 增加（4.7 ± 3.1 mL·cmH₂O·L⁻¹·s 对比 1.0 ± 0.8 mL·cmH₂O·L⁻¹·s；p < 0.01）以及 DR,L 增加（4.9 ± 2.6 mL·cmH₂O·L⁻¹·s 对比 1.5 ± 0.8 mL·cmH₂O·L⁻¹·s；p < 0.01）；（3）FRC 降低（0.665 ± 0.191 L 对比 1.691 ± 0.325 L；p < 0.01）；（4）使肺充气（0.91 ± 0.25 J/L 对比 0.34 ± 0.08 J/L；p < 0.01）和胸壁充气（0.39 ± 0.13 J/L 对比 0.18 ± 0.04 J/L；p < 0.01）所做的功增加；以及（5）肺氧合指数（PaO₂/PAO₂ 比值）降低。