Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation

Abstract Objectives Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O2 pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE). Methods Thirty-one patients of both sexes, aged 45 to 75 years, with symptomatic (Canadian Cardiovascular Society class II to IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov: NCT03218891. Results The patients had low cardiorespiratory capacity (OUES of 1.74 ± 0.4 L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O2 pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R = 0.48; p = 0.019). Conclusion Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O2 pulse response during CEPT and contractile alterations detected by exercise stress echocardiography. Highlights OUES analysis is useful for assessing functional capacity in refractory angina. O2 pulse curve is correlated with contractile alterations in exercise echocardiogram. Cardiopulmonary exercise test is useful toll in patients with refractory angina.

Resposta cardiorrespiratoria e gasto energetico em exercicio na maxima fase estavel de lactato / Cardiorespiratory response and energy expenditure during exercise at maximal lactate steady state

A resposta cardiorrespiratória durante exercícios submáximos, na intensidade da máxima fase estável de lactato (MFELint) até a exaustão, tem sido pouco investigada. O objetivo deste estudo foi investigar a resposta do consumo de oxigênio (VO2), frequência cardíaca (FC) e pulso de oxigênio (pulso O2) em exercício realizado na MFELint até a exaustão, e comparar o gasto energético (GE) estimado pelo VO2 e pela FC. Doze sujeitos treinados realizaram um protocolo incremental em cicloergômetro para determinar parâmetros máximos e submáximos do metabolismo aeróbio. Posteriormente, foram realizados 2 a 4 testes de 30 min com carga constante para identificar a MFELint. Finalmente, os sujeitos realizaram um teste até a exaustão na MFELint. Os parâmetros cardiorrespiratórios foram medidos continuamente durante todos os testes. No teste de exaustão, as respostas fisiológicas foram comparadas entre seis momentos relativos do tempo de exaustão (TTE). O TTE médio foi 55,1±10,2 min. O pulso de O2 apresentou reduções significativas ao longo do tempo, atingindo, no momento da exaustão, um valor ~ 9% inferior comparado ao início do exercício. Este fato ocorreu pelo aumento da FC ao longo do tempo de forma desproporcional ao aumento do VO2, resultando em diferenças significantes entre os GE estimados. Portanto, em exercício realizado na MFELint até a exaustão, parece existir uma perda gradual da eficiência cardiorrespiratória, evidenciada pela redução do pulso O2. Assim, a relação direta entre VO2 e FC com a carga de trabalho é alterada ao longo do exercício, conduzindo a erros de estimativa do GE a partir dos valores da FC.

There has been little research regarding cardiorespiratory responses during submaximal exercise at the maximal lactate steady state intensity (MLSSint) until exhaustion. The objective of this study was to investigate the responses of oxygen consumption (VO2), heart rate (HR) and oxygen pulse (O2 pulse) during exercise to exhaustion at MLSSint, and to compare energy expenditure (EE) estimated by VO2 and HR. Twelve trained athletes followed an incremental protocol on a cycle ergometer to determine maximal and submaximal parameters of aerobic metabolism. On subsequent occasions they performed 2 to 4 30-minute tests with constant load to identify MLSSint. Finally, they underwent a test to exhaustion at MLSSint. Cardiorespiratory parameters were measured continuously during all tests. During the test to exhaustion, physiological responses were compared for six points in time calculated as percentages of the time to exhaustion (TTE). Mean TTE was 55.1±10.2 min. Oxygen pulse presented significant reduction over time, decreasing to a value 9% lower than baseline at the exhaustion point. This fact was the result of increases in HR over time that was disproportional to the increase in VO2, resulting in significant differences between EE estimates. Therefore, there appears to be a gradual loss of cardiorespiratory efficiency during exercise to exhaustion at MLSSint that is shown by the reduction in O2 pulse. The direct relationship between VO2 and HR with workload presents variations over the course of exercise, leading to errors when EE is estimated using HR.

Comparação das respostas cardiorrespiratórias de repouso entre os meios terrestre e aquático / Comparison of cardiorespiratory responses at rest between land and water environments

Os menores valores de frequência cardíaca (FC) no meio aquático são bem consolidados na literatura. No entanto, as respostas de consumo de oxigênio (VO2) e pulso de oxigênio (PulsoO2) em imersão em repouso são menos investigadas e os estudos que realizaram tal análise apresentam diferentes resultados, permanecendo uma lacuna acerca dessa comparação na literatura. Dessa forma, o objetivo do presente estudo foi analisar os valores de FC, VO2 e PulsoO2 em repouso nos meios terrestre e aquático. Sessenta mulheres (24,0 ± 2,5 anos) participaram do presente estudo. Inicialmente, as participantes permaneceram 30 minutos em repouso em decúbito dorsal fora da água. A seguir, os valores de FC, VO2 e PulsoO2 foram avaliados na posição ortostática nos meios terrestre (MT) e aquático (MA). Utilizou-se Teste T pareado para comparar as variáveis entre os meios, adotando-se um alfa de 5%. Como resultados, a FC apresentou redução significativa do MT para o MA. Por outro lado, observou-se aumento significativo nas variáveis VO2 e PulsoO2 da situação de repouso em MT para MA. Portanto, as respostas cardiorrespiratórias diferem entre os meios aquático e terrestre, sendo que as respostas de FC são reduzidas enquanto as de VO2 e PulsoO2 são incrementadas com a imersão em repouso.

The lower values of heart rate (HR) in the aquatic environment are well-established in the literature. However, the oxygen consumption (VO2) and oxygen pulse (PulseO2) responses in immersion at rest are poorly investigated, and the studies that performed such analysis show different results, remaining a gap in the literature about this comparison. Thus, the purpose of the present study was to analyze the HR, VO2 and PulseO2 values at rest on dry land and in the aquatic environments. Sixty young women (24.0 ± 2.5 years) participated of the present study. Initially, the participants remained 30 minutes at rest in the supine position out of water. Then, the HR, VO2 and PulseO2 were assessed in the orthostatic position on dry land (DL) and in the aquatic environments (AE). Paired T test was used to compare the variables between the environments, adopting an alpha level of 5%. As results, the HR presented a significant reduction from DL to the AE. On the other hand, it was observed a significant increase in the VO2 and PulseO2 at rest from the DL to AE. Therefore, the results demonstrated that the environment exerts influence on the cardiorespiratory response, because the HR responses are reduced, while the VO2 and PulseO2 are increased with the immersion at rest.

COMPARISON OF RESPONSES OF OXYGEN CONSUMPTION AND HEART RATE BY GYMNASTIC EXERCISE IN WARM WATER TO EXERCISE ON LAND / 体力科学

Aim of the present study is to clarify energy expenditure of gymnastic exercise during water immersion. Method : 13 males participated to the test. Oxygen consumption (VO₂) and ventilation were continuously measured by open circuit. Heart rate (HR) was automatically obtained by telemetoring. Six kinds of repeating movement of extremities were performed on land and in water in the same manner. Immersing depth was to the xyphoid level. Rhythms of the movement were adjusted so as to continue for several minutes. Result : Their OPW were 14∼20 ml/kg/min, MV were 38∼53 l/min. OPW increased remarkably by swings of both arms crossing in front of chest or alternant back-and-forth, and swings of a hemi-leg in water, compared to that on land. OPW was as half as on land by jump in situ, and equivalent by steps like marching. Notably, oxygen pulse increased by arm and leg exercise more than that on land, accompanied by increase of ventilation. Gymnastic exercise in water showed different effect on oxygen consumption and cardiac response from that on land. Manner of the movements in water also affect the difference. Those kinds of exercise in water can be utilized clinically for training and promotion of fitness.

Early Response of Cardiopulmonary Exercise Test in Patients with Locally Advanced Non-Small Cell Lung Cancer Treated with Systemic Chemotherapy / 결핵

BACKGROUND: The effects of chemotherapy on pulmonary function are mainly a reduced diffusion capacity and a restrictive ventilatory impairment. Exercise can expose cardiovascular and pulmonary abnormalities not evident at rest. Exercise related cardiopulmonary function is important in patients with malignant disease as a determinant of quality of life. We performed this study to evaluate the changes of body composition and cardiopulmonary exercise performance of patients with locally advanced, non-small cell, lung cancer (NSCLC) before and after chemotherapy. METHODS: We evaluated resting pulmonary function, body composition, physiologic performance status, and cardiopulmonary exercise function in 11 patients with locally advanced NSCLC, at diagnosis and prior to the fourth cycle of chemotherapy. RESULTS: After chemotherapy, 4 patients (36.4%) showed partial response and 7 (63.4%) had stable disease. After chemotherapy, diffusion capacity of the lung for carbon monoxide was reduced (89.7+/-34.1%, vs. 71.9+/-20.5%) but not significantly. There were no significant changes in body composition or the state of physiologic performance after chemotherapy. There was a significant impairment of cardiopulmonary exercise tolerance in patients with NSCLC, evidenced by a reduction of maximal oxygen uptake (VO2max, ml/kg/min, 17.9+/-2.6 : 12.6+/-6.1, <0.05) and O2 pulse (O2 pulse, ml/beat, 7.0+/-1.7, 5.2+/-2.1, <0.05). CONCLUSION: Systemic chemotherapy resulted in a loss of cardiopulmonary exercise function in patients with locally advanced NSCLC within the short-term period, but not a physiologic change of body composition within the same period.

Desaturation of Pulse Oximetry by Intraoperative Using of Subcutaneous Blue Dye: A case report / 대한마취과학회지

Pulse oximetry is a noninvasive, reusable device that is being used routinely in anesthesia procedure for monitoring oxygen saturation. This is a very beneficial device that can quickly detect of hypoxia, the most common cause of anesthesia-related death. However, in clinical uses, false desaturation readings are frequently found to be caused by various factors. Such as by the use of intraoperative blue dye, which can falsely decrease oxygen saturation as determined by pulse oximetry. We therefore report our findings concerning prolonged decreased pulse oximetry readings due to the intraoperative use of blue dye subcutaneously.