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
Background The dead space fraction(VD/VT)has proven to be a powerful predictor of higher mortality in acute respiratory distress syndrome(ARDS).However,its measurement relies on expired carbon dioxide,limiting its wid...Background The dead space fraction(VD/VT)has proven to be a powerful predictor of higher mortality in acute respiratory distress syndrome(ARDS).However,its measurement relies on expired carbon dioxide,limiting its widespread application in clinical practice.Several estimates employing routine variables have been found to be reliable substitutes for direct measurement of VD/VT.In this study,we evaluated the prognostic value of these dead space estimates obtained in the first 7 days following the initiation of ventilation.Methods This retrospective observational study was conducted using data from the Chinese database in intensive care(CDIC).Eligible participants were adult ARDS patients receiving invasive mechanical ventilation while in the intensive care unit between 1st January 2014 and 31st March 2021.We collected data during the first 7 days of ventilation to calculate various dead space estimates,including ventilatory ratio(VR),corrected minute ventilation(V_(Ecorr)),VD/VT(Harris–Benedict),VD/VT(Siddiki estimate),and VD/VT(Penn State estimate)longitudinally.A time-dependent Cox model was used to handle these time-varying estimates.Results A total of 392 patients(median age 66[interquartile range:55–77]years,median SOFA score 9[interquartile range:7–12])were finally included in our analysis,among whom 132(33.7%)patients died within 28 days of admission.VR(hazard ratio[HR]=1.04 per 0.1 increase,95%confidence interval[CI]:1.01 to 1.06;P=0.013),V_(Ecorr)(HR=1.08 per 1 increase,95%CI:1.04 to 1.12;P<0.001),VD/VT(Harris–Benedict)(HR=1.25 per 0.1 increase,95%CI:1.06 to 1.47;P=0.006),and VD/VT(Penn State estimate)(HR=1.22 per 0.1 increase,95%CI:1.04 to 1.44;P=0.017)remained significant after adjustment,while VD/VT(Siddiki estimate)(HR=1.10 per 0.1 increase,95%CI:1.00 to 1.20;P=0.058)did not.Given a large number of negative values,VD/VT(Siddiki estimate)and VD/VT(Penn State estimate)were not recommended as reliable substitutes.Long-term exposure to VR>1.3,V_(Ecorr)>7.53,and VD/VT(Harris–Benedict)>0.59 was independently associated with an increased risk of mortality in ARDS patients.These findings were validated in the fluid and catheter treatment trial(FACTT)database.Conclusions In cases where VD/VT cannot be measured directly,early time-varying estimates of VD/VT such as VR,,V_(Ecorr),and VD/VT(Harris–Benedict)can be considered for predicting mortality in ARDS patients,offering a rapid bedside application.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.
基金supported by the Key Technologies Research and Development Program(Grant numbers:2022YFC2504400 and 2021YFC2500804)the Jiangsu Provincial Key Research and Development Program(Grant number:BE2022854).
文摘Background The dead space fraction(VD/VT)has proven to be a powerful predictor of higher mortality in acute respiratory distress syndrome(ARDS).However,its measurement relies on expired carbon dioxide,limiting its widespread application in clinical practice.Several estimates employing routine variables have been found to be reliable substitutes for direct measurement of VD/VT.In this study,we evaluated the prognostic value of these dead space estimates obtained in the first 7 days following the initiation of ventilation.Methods This retrospective observational study was conducted using data from the Chinese database in intensive care(CDIC).Eligible participants were adult ARDS patients receiving invasive mechanical ventilation while in the intensive care unit between 1st January 2014 and 31st March 2021.We collected data during the first 7 days of ventilation to calculate various dead space estimates,including ventilatory ratio(VR),corrected minute ventilation(V_(Ecorr)),VD/VT(Harris–Benedict),VD/VT(Siddiki estimate),and VD/VT(Penn State estimate)longitudinally.A time-dependent Cox model was used to handle these time-varying estimates.Results A total of 392 patients(median age 66[interquartile range:55–77]years,median SOFA score 9[interquartile range:7–12])were finally included in our analysis,among whom 132(33.7%)patients died within 28 days of admission.VR(hazard ratio[HR]=1.04 per 0.1 increase,95%confidence interval[CI]:1.01 to 1.06;P=0.013),V_(Ecorr)(HR=1.08 per 1 increase,95%CI:1.04 to 1.12;P<0.001),VD/VT(Harris–Benedict)(HR=1.25 per 0.1 increase,95%CI:1.06 to 1.47;P=0.006),and VD/VT(Penn State estimate)(HR=1.22 per 0.1 increase,95%CI:1.04 to 1.44;P=0.017)remained significant after adjustment,while VD/VT(Siddiki estimate)(HR=1.10 per 0.1 increase,95%CI:1.00 to 1.20;P=0.058)did not.Given a large number of negative values,VD/VT(Siddiki estimate)and VD/VT(Penn State estimate)were not recommended as reliable substitutes.Long-term exposure to VR>1.3,V_(Ecorr)>7.53,and VD/VT(Harris–Benedict)>0.59 was independently associated with an increased risk of mortality in ARDS patients.These findings were validated in the fluid and catheter treatment trial(FACTT)database.Conclusions In cases where VD/VT cannot be measured directly,early time-varying estimates of VD/VT such as VR,,V_(Ecorr),and VD/VT(Harris–Benedict)can be considered for predicting mortality in ARDS patients,offering a rapid bedside application.
