Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives:...Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives: In this retrospective pilot study, we evaluated patients with hematologic and solid malignancies by CPET to determine the primary source of their dyspnea. Methods: Subjects were exercised on a cycle ergometer with increasing workloads. Minute ventilation, heart rate, breathing reserve, oxygen uptake (V’O<sub>2</sub>), O<sub>2</sub>-pulse, ventilatory equivalents for carbon dioxide and oxygen (V’<sub>E</sub>/V’CO<sub>2</sub> and V’<sub>E</sub>/V’O<sub>2</sub>, respectively) were measured at baseline and peak exercise. The slope and intercept for V’<sub>E</sub>/V’CO<sub>2</sub> was computed for all subjects. Peak V’O<sub>2</sub> 4% predicted indicated a circulatory or ventilatory limitation. Results: Complete clinical and physiological data were available for 36 patients (M/F 20/16);32 (89%) exhibited ventilatory or circulatory limitation as shown by a reduced peak V’O<sub>2</sub> and 10 subjects with normal physiologic data. The largest cohort comprised the pulmonary vascular group (n = 18) whose mean ± SD peak V’O<sub>2</sub> was 61% ± 17% predicted. There were close associations between V’O<sub>2</sub> and spirometric values. Peak V’<sub>E</sub>/V’O<sub>2</sub> and V’<sub>E</sub>/V’CO<sub>2</sub> were highest in the circulatory and ventilatory cohorts, consistent with increase in dead space breathing. The intercept of the V’<sub>E</sub>-V’CO<sub>2</sub> relationship was lowest in patients with cardiovascular impairment. Conclusion: Dyspneic patients with malignancies exhibit dead space breathing, many exhibiting a circulatory source for exercise limitation with a prominent pulmonary vascular component. Potential factors include effects of chemo- and radiation therapy on cardiac function and pulmonary vascular endothelium.展开更多
肺保护性通气(lung protective ventilation,LPV)策略可在一定程度上减少小儿术中机械通气肺损伤的发生。小潮气量、呼气末正压(positive end expiratory pressure,PEEP)和肺复张是小儿LPV策略的主要措施;此外,FiO_(2)、驱动压等对小儿...肺保护性通气(lung protective ventilation,LPV)策略可在一定程度上减少小儿术中机械通气肺损伤的发生。小潮气量、呼气末正压(positive end expiratory pressure,PEEP)和肺复张是小儿LPV策略的主要措施;此外,FiO_(2)、驱动压等对小儿肺保护的重要性也不容忽视。文章分析总结了有关小儿LPV策略的文献资料发现,虽然相关研究取得了阶段性的成果,但小儿LPV策略的发展远滞后于成年人,各项措施的最佳实施水平也有待确认。小儿LPV研究面临的困境主要包括理想体重(ideal body weight,IBW)的计算、机械死腔的影响、氧合和力学的矛盾平衡等,需要大量长期的临床研究进行探究,以降低术后肺部并发症(postoperative pulmonary complications,PPCs)的发生率,改善小儿预后。展开更多
文摘Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives: In this retrospective pilot study, we evaluated patients with hematologic and solid malignancies by CPET to determine the primary source of their dyspnea. Methods: Subjects were exercised on a cycle ergometer with increasing workloads. Minute ventilation, heart rate, breathing reserve, oxygen uptake (V’O<sub>2</sub>), O<sub>2</sub>-pulse, ventilatory equivalents for carbon dioxide and oxygen (V’<sub>E</sub>/V’CO<sub>2</sub> and V’<sub>E</sub>/V’O<sub>2</sub>, respectively) were measured at baseline and peak exercise. The slope and intercept for V’<sub>E</sub>/V’CO<sub>2</sub> was computed for all subjects. Peak V’O<sub>2</sub> 4% predicted indicated a circulatory or ventilatory limitation. Results: Complete clinical and physiological data were available for 36 patients (M/F 20/16);32 (89%) exhibited ventilatory or circulatory limitation as shown by a reduced peak V’O<sub>2</sub> and 10 subjects with normal physiologic data. The largest cohort comprised the pulmonary vascular group (n = 18) whose mean ± SD peak V’O<sub>2</sub> was 61% ± 17% predicted. There were close associations between V’O<sub>2</sub> and spirometric values. Peak V’<sub>E</sub>/V’O<sub>2</sub> and V’<sub>E</sub>/V’CO<sub>2</sub> were highest in the circulatory and ventilatory cohorts, consistent with increase in dead space breathing. The intercept of the V’<sub>E</sub>-V’CO<sub>2</sub> relationship was lowest in patients with cardiovascular impairment. Conclusion: Dyspneic patients with malignancies exhibit dead space breathing, many exhibiting a circulatory source for exercise limitation with a prominent pulmonary vascular component. Potential factors include effects of chemo- and radiation therapy on cardiac function and pulmonary vascular endothelium.
文摘肺保护性通气(lung protective ventilation,LPV)策略可在一定程度上减少小儿术中机械通气肺损伤的发生。小潮气量、呼气末正压(positive end expiratory pressure,PEEP)和肺复张是小儿LPV策略的主要措施;此外,FiO_(2)、驱动压等对小儿肺保护的重要性也不容忽视。文章分析总结了有关小儿LPV策略的文献资料发现,虽然相关研究取得了阶段性的成果,但小儿LPV策略的发展远滞后于成年人,各项措施的最佳实施水平也有待确认。小儿LPV研究面临的困境主要包括理想体重(ideal body weight,IBW)的计算、机械死腔的影响、氧合和力学的矛盾平衡等,需要大量长期的临床研究进行探究,以降低术后肺部并发症(postoperative pulmonary complications,PPCs)的发生率,改善小儿预后。
