Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
Weight Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
Chest. 2021 Jun;159(6):2373-2383. doi: 10.1016/j.chest.2021.01.055. Epub 2021 May 8.
Increased pleural pressure affects the mechanics of breathing of people with class III obesity (BMI > 40 kg/m).
What are the acute effects of CPAP titrated to match pleural pressure on cardiopulmonary function in spontaneously breathing patients with class III obesity?
We enrolled six participants with BMI within normal range (control participants, group I) and 12 patients with class III obesity (group II) divided into subgroups: IIa, BMI of 40 to 50 kg/m; and IIb, BMI of ≥ 50 kg/m. The study was performed in two phases: in phase 1, participants were supine and breathing spontaneously at atmospheric pressure, and in phase 2, participants were supine and breathing with CPAP titrated to match their end-expiratory esophageal pressure in the absence of CPAP. Respiratory mechanics, esophageal pressure, and hemodynamic data were collected, and right heart function was evaluated by transthoracic echocardiography.
The levels of CPAP titrated to match pleural pressure in group I, subgroup IIa, and subgroup IIb were 6 ± 2 cmHO, 12 ± 3 cmHO, and 18 ± 4 cmHO, respectively. In both subgroups IIa and IIb, CPAP titrated to match pleural pressure decreased minute ventilation (IIa, P = .03; IIb, P = .03), improved peripheral oxygen saturation (IIa, P = .04; IIb, P = .02), improved homogeneity of tidal volume distribution between ventral and dorsal lung regions (IIa, P = .22; IIb, P = .03), and decreased work of breathing (IIa, P < .001; IIb, P = .003) with a reduction in both the work spent to initiate inspiratory flow as well as tidal ventilation. In five hypertensive participants with obesity, BP decreased to normal range, without impairment of right heart function.
In ambulatory patients with class III obesity, CPAP titrated to match pleural pressure decreased work of breathing and improved respiratory mechanics while maintaining hemodynamic stability, without impairing right heart function.
ClinicalTrials.gov; No.: NCT02523352; URL: www.clinicaltrials.gov.
增加胸膜压力会影响 III 类肥胖（BMI>40kg/m）人群的呼吸力学。
CPAP 滴定至匹配胸膜压力对自主呼吸的 III 类肥胖患者心肺功能的急性影响是什么？
我们招募了 6 名 BMI 在正常范围内的参与者（对照组，I 组）和 12 名 III 类肥胖患者（II 组），分为亚组：IIa，BMI 为 40 至 50kg/m；IIb，BMI≥50kg/m。研究分两个阶段进行：在第一阶段，参与者仰卧并在大气压下自主呼吸；在第二阶段，参与者仰卧并在无 CPAP 的情况下用滴定至匹配其呼气末食管压力的 CPAP 呼吸。收集呼吸力学、食管压力和血流动力学数据，并通过经胸超声心动图评估右心功能。
I 组、IIa 亚组和 IIb 亚组匹配胸膜压力的 CPAP 滴定水平分别为 6±2cmHO、12±3cmHO 和 18±4cmHO。在 IIa 和 IIb 亚组中，匹配胸膜压力的 CPAP 滴定均降低分钟通气量（IIa，P=0.03；IIb，P=0.03），提高外周血氧饱和度（IIa，P=0.04；IIb，P=0.02），改善腹侧和背侧肺区潮气量分布的均匀性（IIa，P=0.22；IIb，P=0.03），降低呼吸功（IIa，P<0.001；IIb，P=0.003），同时降低吸气流量起始时的功和潮气量。在五名肥胖的高血压患者中，血压降至正常范围，而右心功能未受损。
在 III 类肥胖的门诊患者中，CPAP 滴定至匹配胸膜压力可降低呼吸功，改善呼吸力学，同时保持血流动力学稳定，而不损害右心功能。
ClinicalTrials.gov；编号：NCT02523352；网址：www.clinicaltrials.gov。
