Valenza Franco, Vagginelli Federica, Tiby Alberto, Francesconi Silvia, Ronzoni Giulio, Guglielmi Massimiliano, Zappa Marco, Lattuada Ezio, Gattinoni Luciano
Istituto di Anestesia e Rianimazione, Fondazione Ospedale Maggiore, Mangiagalli e Regina Elena-IRCCS, Milan, Italy.
Anesthesiology. 2007 Nov;107(5):725-32. doi: 10.1097/01.anes.0000287026.61782.a6.
The authors studied the effects of the beach chair (BC) position, 10 cm H2O positive end-expiratory pressure (PEEP), and pneumoperitoneum on respiratory function in morbidly obese patients undergoing laparoscopic gastric banding.
The authors studied 20 patients (body mass index 42 +/- 5 kg/m2) during the supine and BC positions, before and after pneumoperitoneum was instituted (13.6 +/- 1.2 mmHg). PEEP was applied during each combination of position and pneumoperitoneum. The authors measured elastance (E,rs) of the respiratory system, end-expiratory lung volume (helium technique), and arterial oxygen tension. Pressure-volume curves were also taken (occlusion technique). Patients were paralyzed during total intravenous anesthesia. Tidal volume (10.5 +/- 1 ml/kg ideal body weight) and respiratory rate (11 +/- 1 breaths/min) were kept constant throughout.
In the supine position, respiratory function was abnormal: E,rs was 21.71 +/- 5.26 cm H2O/l, and end-expiratory lung volume was 0.46 +/- 0.1 l. Both the BC position and PEEP improved E,rs (P < 0.01). End-expiratory lung volume almost doubled (0.83 +/- 0.3 and 0.85 +/- 0.3 l, BC and PEEP, respectively; P < 0.01 vs. supine zero end-expiratory pressure), with no evidence of lung recruitment (0.04 +/- 0.1 l in the supine and 0.07 +/- 0.2 in the BC position). PEEP was associated with higher airway pressures than the BC position (22.1 +/- 2.01 vs. 13.8 +/- 1.8 cm H2O; P < 0.01). Pneumoperitoneum further worsened E,rs (31.59 +/- 6.73; P < 0.01) and end-expiratory lung volume (0.35 +/- 0.1 l; P < 0.01). Changes of lung volume correlated with changes of oxygenation (linear regression, R2 = 0.524, P < 0.001) so that during pneumoperitoneum, only the combination of the BC position and PEEP improved oxygenation.
The BC position and PEEP counteracted the major derangements of respiratory function produced by anesthesia and paralysis. During pneumoperitoneum, only the combination of the two maneuvers improved oxygenation.
作者研究了沙滩椅（BC）位、10 cmH₂O呼气末正压（PEEP）和气腹对接受腹腔镜胃束带术的病态肥胖患者呼吸功能的影响。
作者研究了20例患者（体重指数42±5kg/m²），记录其仰卧位和BC位时、气腹建立前后（13.6±1.2mmHg）的情况。在每种体位和气腹的组合状态下均应用PEEP。作者测量了呼吸系统弹性（E,rs）、呼气末肺容积（氦稀释法）和动脉血氧张力。同时还绘制了压力-容积曲线（阻断法）。患者在全静脉麻醉期间处于肌肉松弛状态。潮气量（10.5±1ml/kg理想体重）和呼吸频率（11±1次/分钟）在整个过程中保持恒定。
在仰卧位时，呼吸功能异常：E,rs为21.71±5.26cmH₂O/l，呼气末肺容积为0.46±0.1l。BC位和PEEP均改善了E,rs（P<0.01）。呼气末肺容积几乎增加了一倍（BC位和PEEP分别为0.83±0.3l和0.85±0.3l；与仰卧位零呼气末正压相比P<0.01），且无肺复张迹象（仰卧位时为0.04±
