INTRODUCTION: Post-operative oxygen therapy is used to prevent hypoxemia and surgical site infection. However, with improvements of anesthesia techniques, post-operative hypoxemia incidence is declining and the benefits of oxygen on surgical site infection have been questioned. Moreover, hyperoxemia might have adverse effects on the pulmonary and cardiovascular systems. We hypothesized hyperoxemia post thoracic surgery is associated with post-operative pulmonary and cardiovascular complications. METHODS: Consecutive lung resection patients were included in this post-hoc analysis. Post-operative pulmonary and cardiovascular complications were prospectively assessed during the first 30 post-operative days, or hospital stay. Arterial blood gases were analyzed at 1, 6 and 12 h after surgery. Hyperoxemia was defined as arterial partial pressure of oxygen (PaO2)>100 mmHg. Patients with hyperoxemia duration in at least two adjacent time points were considered as hyperoxemic. Student t-test, Mann-Whitney U test and two-tailed Fisher exact test were used for group comparison. P values < 0.05 were considered statistically significant. RESULTS: Three hundred sixty-three consecutive patients were included in this post-hoc analysis. Two hundred five patients (57%), were considered hyperoxemic and included in the hyperoxemia group. Patients in the hyperoxemia group had significantly higher PaO2 at 1, 6 and 12 h after surgery (p < 0.05). Otherwise, there was no significant difference in age, sex, comorbidities, pulmonary function tests parameters, lung surgery procedure, incidence of post-operative pulmonary and cardiovascular complications, intensive care unit and hospital length of stay and 30-day mortality. CONCLUSION: Hyperoxemia after lung resection surgery is common and not associated with post-operative complications or 30-day mortality.

• Publication type
• Journal Article MeSH

INTRODUCTION: According to the guidelines for preoperative assessment of lung resection candidates, patients with normal forced expiratory volume in 1 s (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) are at low risk for post-operative pulmonary complications (PPC). However, PPC affect hospital length of stay and related healthcare costs. We aimed to assess risk of PPC for lung resection candidates with normal FEV1 and DLCO (>80% predicted) and identify factors associated with PPC. METHODS: 398 patients were prospectively studied at two centres between 2017 and 2021. PPC were recorded from the first 30 post-operative days. Subgroups of patients with and without PPC were compared and factors with significant difference were analysed by uni- and multivariate logistic regression. RESULTS: 188 subjects had normal FEV1 and DLCO. Of these, 17 patients (9%) developed PPC. Patients with PPC had significantly lower pressure of end-tidal carbon dioxide (PETCO2 ) at rest (27.7 versus 29.9; p=0.033) and higher ventilatory efficiency (V'E/V'CO2 ) slope (31.1 versus 28; p=0.016) compared to those without PPC. Multivariate models showed association between resting PETCO2 (OR 0.872; p=0.035) and V'E/V'CO2 slope (OR 1.116; p=0.03) and PPC. In both models, thoracotomy was strongly associated with PPC (OR 6.419; p=0.005 and OR 5.884; p=0.007, respectively). Peak oxygen consumption failed to predict PPC (p=0.917). CONCLUSIONS: Resting PETCO2 adds incremental information for risk prediction of PPC in patients with normal FEV1 and DLCO. We propose resting PETCO2 be an additional parameter to FEV1 and DLCO for preoperative risk stratification.

• Publication type
• Journal Article MeSH

BACKGROUND: Cardiopulmonary exercise testing parameters including ventilatory efficiency (VE/VCO2 slope) are used for risk assessment of lung resection candidates. However, many patients are unable or unwilling to undergo exercise. VE/VCO2 slope is closely related to the partial pressure of end-tidal carbon dioxide (PETCO2). We hypothesized PETCO2 at rest predicts postoperative pulmonary complications. METHODS: Consecutive lung resection candidates were included in this prospective multicenter study. Postoperative respiratory complications were assessed from the first 30 postoperative days or from the hospital stay. Student t test or Mann-Whitney U test was used for comparison. Multivariate stepwise logistic regression analysis was used to analyze association with the development of postoperative pulmonary complications. The De Long test was used to compare area under the curve (AUC). Data are summarized as median (interquartile range). RESULTS: Three hundred fifty-three patients were analyzed, of which 59 (17%) developed postoperative pulmonary complications. PETCO2 at rest was significantly lower (27 [24-30] vs 29 [26-32] mm Hg; P < .01) and VE/VCO2 slope during exercise significantly higher (35 [30-40] vs 29 [25-33]; P < .01) in patients who developed postoperative pulmonary complications. Both rest PETCO2 with odds ratio 0.90 (95% confidence interval [CI] 0.83-0.97); P = .01 and VE/VCO2 slope with odds ratio 1.10 (95% CI 1.05-1.16); P < .01 were independently associated with postoperative pulmonary complications by multivariate stepwise logistic regression analysis. There was no significant difference between AUC of both models (rest PETCO2: AUC = 0.79 (95% CI 0.74-0.85); VE/VCO2 slope: AUC = 0.81 (95% CI 0.75-0.86); P = .48). CONCLUSIONS: PETCO2 at rest has similar prognostic utility as VE/VCO2 slope, suggesting rest PETCO2 may be used for postoperative pulmonary complications prediction in lung resection candidates.

• MeSH
• Humans MeSH
• Carbon Dioxide * MeSH
• Lung MeSH
• Prospective Studies MeSH
• Oxygen Consumption MeSH
• Heart Failure * MeSH
• Exercise Test MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH

INTRODUCTION: Ventilatory efficiency (VE/VCO2 slope) has been shown superior to peak oxygen consumption (VO2) for prediction of post-operative pulmonary complications in patients undergoing thoracotomy. VE/VCO2 slope is determined by ventilatory drive and ventilation/perfusion mismatch whereas VO2 is related to cardiac output and arteriovenous oxygen difference. We hypothesized pre-operative VO2 predicts post-operative cardiovascular complications in patients undergoing lung resection. METHODS: Lung resection candidates from a published study were evaluated by post-hoc analysis. All of the patients underwent preoperative cardiopulmonary exercise testing. Post-operative cardiovascular complications were assessed during the first 30 post-operative days or hospital stay. One-way analysis of variance or the Kruskal-Wallis test, and multivariate logistic regression were used for statistical analysis and data summarized as median (IQR). RESULTS: Of 353 subjects, 30 (9%) developed pulmonary complications only (excluded from further analysis), while 78 subjects (22%) developed cardiovascular complications and were divided into two groups for analysis: cardiovascular only (n = 49) and cardiovascular with pulmonary complications (n = 29). Compared to patients without complications (n = 245), peak VO2 was significantly lower in the cardiovascular with pulmonary complications group [19.9 ml/kg/min (16.5-25) vs. 16.3 ml/kg/min (15-20.3); P<0.01] but not in the cardiovascular only complications group [19.9 ml/kg/min (16.5-25) vs 19.0 ml/kg/min (16-23.1); P = 0.18]. In contrast, VE/VCO2 slope was significantly higher in both cardiovascular only [29 (25-33) vs. 31 (27-37); P = 0.05] and cardiovascular with pulmonary complication groups [29 (25-33) vs. 37 (34-42); P<0.01)]. Logistic regression analysis showed VE/VCO2 slope [OR = 1.06; 95%CI (1.01-1.11); P = 0.01; AUC = 0.74], but not peak VO2 to be independently associated with post-operative cardiovascular complications. CONCLUSION: VE/VCO2 slope is superior to peak VO2 for prediction of post-operative cardiovascular complications in lung resection candidates.

• MeSH
• Oxygen MeSH
• Humans MeSH
• Lung surgery   MeSH
• Prognosis MeSH
• Oxygen Consumption * MeSH
• Heart Failure * MeSH
• Exercise Test MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

• Publication type
• Meeting Abstract MeSH

BACKGROUND: Exercise oscillatory ventilation (EOV) is a consequence of ventilatory control system instability and is commonly observed in patients with advanced heart failure (HF); it is associated with adverse prognosis. The goal of this study was to evaluate the effects of cardiac resynchronization therapy (CRT) on oscillatory ventilation as quantified by a proposed EOV score. METHODS AND RESULTS: Consecutive patients with HF (N = 35) who underwent clinically indicated CRT, cardiopulmonary exercise testing and carbon dioxide (CO2) chemosensitivity by rebreathe before and 4-6 months after CRT were included in this post hoc analysis. With CRT, EOV scores improved in 22 patients (63%). In these patients, left ventricular ejection fraction, left atrial volume, brain natriuretic peptide concentration, and CO2 chemosensitivity significantly improved after CRT (P < 0.05). Furthermore, minute ventilation per unit CO2 production significantly decreased, and end-tidal CO2 increased at rest and at peak exercise post-CRT. Multiple regression analysis showed only the change of CO2 chemosensitivity to be significantly associated with the improvement of the EOV score (b = 0.64; F = 11.3; P = 0.004). In the group without EOV score improvement (n = 13), though left ventricular ejection fraction significantly increased with CRT (P = 0.015), no significant changes in ventilation or gas exchange were observed. CONCLUSION: The EOV score was mitigated by CRT and was associated with decreased CO2 chemosensitivity.

• MeSH
• Ventricular Function, Left MeSH
• Humans MeSH
• Cardiac Resynchronization Therapy * MeSH
• Heart Failure * therapy   MeSH
• Stroke Volume MeSH
• Exercise Test MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Poor ventilatory efficiency, defined as the increase in minute ventilation relative to carbon dioxide production during exercise (VE/VCO2 slope), may be associated with dynamic hyperinflation and thereby promote the development of prolonged air leak (PAL) after lung resection. Consecutive lung lobectomy candidates (n = 96) were recruited for this prospective two-centre study. All subjects underwent pulmonary function tests and cardiopulmonary exercise testing prior to surgery. PAL was defined as the presence of air leaks from the chest tube on the 5th postoperative day and developed in 28 (29%) subjects. Subjects with PAL were not different in terms of age, sex, American Society of Anesthesiologists class, type of surgery (thoracotomy/video-assisted thoracoscopic surgery) and site of surgery (right/left lung; upper/lower lobes). Subjects with PAL had more frequent pleural adhesions (50% vs 21%; P = 0.006) and steeper VE/VCO2 slope (35 ± 7 vs 30 ± 5; P = 0.001). Stepwise logistic regression showed that only the presence of pleural adhesions [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.4-10.9; P = 0.008] and VE/VCO2 slope (OR 1.1, 95% CI 1.0-1.2; P = 0.003) were independently associated with PAL (AUC 0.74, 95% CI 0.62-0.86). We conclude that a high VE/VCO2 slope during exercise may be helpful in identifying patients at greater risk for the development of PAL after lung lobectomy. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03498352.

• MeSH
• Exercise physiology   MeSH
• Thoracic Surgery, Video-Assisted MeSH
• Chest Tubes MeSH
• Middle Aged MeSH
• Humans MeSH
• Logistic Models MeSH
• Lung Diseases mortality   physiopathology   surgery   MeSH
• Pulmonary Ventilation physiology   MeSH
• Pneumonectomy adverse effects   MeSH
• Predictive Value of Tests MeSH
• Prognosis MeSH
• Prospective Studies MeSH
• Respiratory Function Tests MeSH
• Aged MeSH
• Oxygen Consumption physiology   MeSH
• Exercise Test MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The heart and lungs are intimately linked. Hence, impaired function of one organ may lead to changes in the other. Accordingly, heart failure is associated with airway obstruction, loss of lung volume, impaired gas exchange, and abnormal ventilatory control. Cardiopulmonary exercise testing is an excellent tool for evaluation of gas exchange and ventilatory control. Indeed, many parameters routinely measured during cardiopulmonary exercise testing, including the level of minute ventilation per unit of carbon dioxide production and the presence of exercise oscillatory ventilation, have been found to be strongly associated with prognosis in patients with heart failure.

• MeSH
• Humans MeSH
• Lung physiopathology   MeSH
• Heart Failure physiopathology   MeSH
• Pulmonary Gas Exchange physiology   MeSH
• Exercise Test methods   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Research Support, N.I.H., Extramural MeSH

INTRODUCTION: Measurement of ventilatory efficiency, defined as minute ventilation per unit carbon dioxide production (VE/VCO2), by cardiopulmonary exercise testing (CPET) has been proposed as a screen for hyperventilation syndrome (HVS). However, increased VE/VCO2 may be associated with other disorders which need to be distinguished from HVS. A more specific marker of HVS by CPET would be clinically useful. We hypothesized ventilatory control during exercise is abnormal in patients with HVS. METHODS: Patients who underwent CPET from years 2015 through 2017 were retrospectively identified and formed the study group. HVS was defined as dyspnea with respiratory alkalosis (pH >7.45) at peak exercise with absence of acute or chronic respiratory, heart or psychiatric disease. Healthy patients were selected as controls. For comparison the Student t-test or Mann-Whitney U test were used. Data are summarized as mean ± SD or median (IQR); p<0.05 was considered significant. RESULTS: Twenty-nine patients with HVS were identified and 29 control subjects were selected. At rest, end-tidal carbon dioxide (PETCO2) was 27 mmHg (25-30) for HVS patients vs. 30 mmHg (28-32); in controls (p = 0.05). At peak exercise PETCO2 was also significantly lower (27 ± 4 mmHg vs. 35 ± 4 mmHg; p<0.01) and VE/VCO2 higher ((38 (35-43) vs. 31 (27-34); p<0.01)) in patients with HVS. In contrast to controls, there were minimal changes of PETCO2 (0.50 ± 5.26 mmHg vs. 6.2 ± 4.6 mmHg; p<0.01) and VE/VCO2 ((0.17 (-4.24-6.02) vs. -6.6 (-11.4-(-2.8)); p<0.01)) during exercise in patients with HVS. The absence of VE/VCO2 and PETCO2 change during exercise was specific for HVS (83% and 93%, respectively). CONCLUSION: Absence of VE/VCO2 and PETCO2 change during exercise may identify patients with HVS.

• MeSH
• Adult MeSH
• Dyspnea physiopathology   MeSH
• Hyperventilation diagnosis   physiopathology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Carbon Dioxide metabolism   MeSH
• Oxygen Consumption physiology   MeSH
• Heart Failure physiopathology   MeSH
• Exercise Tolerance MeSH
• Exercise Test * MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH

OBJECTIVES: One-lung ventilation (OLV) may be complicated by hypoxemia. Ventilatory efficiency, defined as the ratio of minute ventilation to carbon dioxide output (VE/VCO2), is increased with ventilation/perfusion mismatch and pulmonary artery hypertension, both of which may be associated with hypoxemia. Hence, the authors hypothesized increased VE/VCO2 will predict hypoxemia during OLV. DESIGN: Prospective observational study. SETTING: Single-center, university, tertiary care hospital. PARTICIPANTS: The study comprised 50 consecutive lung resection candidates. INTERVENTIONS: All patients underwent cardiopulmonary exercise testing before surgery. Patients who required inspired oxygen fraction (FiO2) ≥0.7 to maintain arterial oxygen (O2) saturation >90% after 30 minutes of OLV were considered to be hypoxemic. The Student t or Mann-Whitney U test were used for comparison of patients who became hypoxemic and those who did not. Multiple regression analysis adjusted for age, sex, and body mass index was used to evaluate which parameters were associated with the VE/VCO2 slope. Data are summarized as mean ± standard deviation. MEASUREMENTS AND MAIN RESULTS: Twenty-four patients (48%) developed hypoxemia. There was no significant difference in age, sex, and body mass index between hypoxemic and nonhypoxemic patients. However, patients with hypoxemia had a significantly higher VE/VCO2 slope (30 ± 5 v 27 ± 4; p = 0.04) with exercise and lower partial pressure of oxygen/FiO2 (129 ± 92 v 168 ± 88; p = 0.01), higher mean positive end-expiratory pressure (6.6 ± 1.5 v 5.6 ± 0.9 cmH2O; p = 0.02), and lower mean pulse oximetry O2 saturation/FiO2 index (127 ± 20 v 174 ± 17; p < 0.01) during OLV. Multiple regression showed VE/VCO2 to be independently associated with the mean pulse oximetry O2 saturation/FiO2 index (b = -0.28; F = 3.1; p = 0.05). CONCLUSIONS: An increased VE/VCO2 slope may predict hypoxemia development in patients who undergo OLV.

• MeSH
• Adult MeSH
• Hypoxia etiology   MeSH
• Oxygen blood   MeSH
• Middle Aged MeSH
• Humans MeSH
• Pulmonary Ventilation physiology   MeSH
• Prospective Studies MeSH
• Aged MeSH
• Oxygen Consumption MeSH
• One-Lung Ventilation adverse effects   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Observational Study MeSH