Assessment of Cardiorespiratory and Metabolic Responses in Women with Obesity After Surgically Induced Weight Loss: Results from a Pilot Study.

PURPOSE: Bariatric surgery is effective in controlling severe obesity. However, studies investigating the impact of surgically induced weight loss on cardiorespiratory and metabolic responses during maximal effort are controversial. The aim of this study was to assess cardiorespiratory and metabolic responses in women with obesity after bariatric surgery. MATERIALS AND METHODS: We performed a secondary analysis on data from a pilot study with women with obesity submitted to bariatric surgery and who did not participate in a controlled physical training program. Anthropometry, pulmonary function (spirometry), and cardiorespiratory fitness (cardiopulmonary exercise testing [CPX]) were assessed before and after bariatric surgery. RESULTS: Thirty-four women were included (38.7 ± 9.6 years, body mass index = 44.1 ± 6.3 kg/m2). Postoperative assessment was conducted 9.4 ± 2.7 months after surgery. After surgery, we observed a reduction in all anthropometric measurements (mean loss of 28.6 kg, p < 0.001), and improvement in spirometry values (p < 0.001). Relative VO2peak (mL/kg/min) increased slightly (Δ = 1.7; p = 0.06); however, absolute VO2peak (L/min) reduced significantly (Δ = - 0.398; p < 0.001). We also observed an increase of 1.3 min (p < 0.001) in CPX duration, a reduction of 11.3 bpm (p < 0.001) in resting heart rate, and a decrease of systolic (p = 0.02) and diastolic (p < 0.001) blood pressures at peak effort. CONCLUSION: Surgically induced weight loss without exercise training improved cardiac reserve, ventilatory response, blood pressure, and resting heart rate. Cardiorespiratory fitness reflected by relative VO2peak increased slightly, despite increased tolerance to CPX.

Accuracy of single-breath counting test to determine slow vital capacity in hospitalized patients / Acurácia do teste de contagem em uma única respiração para determinar a capacidade vital lenta em pacientes hospitalizados

ABSTRACT Purpose: to identify the accuracy of the single-breath counting test to determine slow vital capacity in hospitalized patients and to evaluate the repeatability of the same examiner. Methods: a diagnostic study and the choice of techniques were randomly assigned. The area under the curve (receiver operating characteristic) was calculated from the slow vital capacity (20ml/kg) to evaluate the best psychometric characteristics of single-breath counting Test for this cutoff point. Repeatability observed by the same examiner was assessed using the Intraclass Correlation Coefficient. Results: 516 patients hospitalized for various diseases were analyzed. In the curve analysis (receiver operating characteristic/slow vital capacity=20ml/Kg), the value of 21 in single-breath counting test with a sensitivity of 94.44% and specificity of 76.62% (area under the curve =0.93, p<0.005) was found. The intraclass correlation coefficient value for the single-breath counting test was 0.976 with p>0.005. Conclusion: the single-breath counting test was a valid and repetitive technique, and may be an important screening option for assessment of lung function in the absence of specific equipment. This technique opens perspectives to replace slow vital capacity measurement in hospitals, which lack spirometric equipment, or in patients who may have a contagious disease, which has a risk of contamination and spread of disease from one patient to another.

RESUMO Objetivo: identificar a acurácia do teste de contagem em uma única respiração para determinar a capacidade vital lenta em pacientes hospitalizados e avaliar sua repetibilidade entre o mesmo examinador. Métodos: estudo de diagnóstico em que a escolha das técnicas foi aleatoriamente atribuída. A área sob a curva (característica de operação do receptor) foi calculada a partir da capacidade vital lenta (20ml/kg) para avaliar as melhores características psicométricas do teste de contagem em uma única respiração para este ponto de corte. A repetibilidade observada pelo mesmo examinador foi avaliada usando o coeficiente de correlação intraclasse. Resultados: foram analisados (característica de operação do receptor/capacidade vital lenta=20ml/Kg), foi encontrado o valor de 21 em teste de contagem em uma única respiração com uma sensibilidade de 94,44% e especificidade de 76,62% (área abaixo da curva=0,93, p<0,005). O valor do coeficiente de correlação intraclasse para o teste de contagem foi 0,976 com p>0,005. Conclusão: o teste de contagem em uma única respiração foi uma técnica válida, repetitiva e pode ser uma importante opção de rastreamento para avaliação da função pulmonar na ausência de equipamentos específicos. Essa técnica abre perspectivas no que se refere à substituição da medição da capacidade vital lenta em hospitais que não possuem equipamento espirométrico ou em pacientes que apresentam uma doença contagiosa com risco de contaminação e propagação de doença de um paciente para outro.

Oxygen uptake efficiency slope as a useful measure of cardiorespiratory fitness in morbidly obese women.

Cardiopulmonary assessment through oxygen uptake efficiency slope (OUES) data has shown encouraging results, revealing that we can obtain important clinical information about functional status. Until now, the use of OUES has not been established as a measure of cardiorespiratory capacity in an obese adult population, only in cardiac and pulmonary diseases or pediatric patients. The aim of this study was to characterize submaximal and maximal levels of OUES in a sample of morbidly obese women and analyze its relationship with traditional measures of cardiorespiratory fitness, anthropometry and pulmonary function. Thirty-three morbidly obese women (age 39.1 ± 9.2 years) performed Cardiopulmonary Exercise Testing (CPX) on a treadmill using the ramp protocol. In addition, anthropometric measurements and pulmonary function were also evaluated. Maximal and submaximal OUES were measured, being calculated from data obtained in the first 50% (OUES50%) and 75% (OUES75%) of total CPX duration. In one-way ANOVA analysis, OUES did not significantly differ between the three different exercise intensities, as observed through a Bland-Altman concordance of 58.9 mL/min/log(L/min) between OUES75% and OUES100%, and 0.49 mL/kg/min/log(l/min) between OUES/kg75% and OUES/kg100%. A strong positive correlation between the maximal (r = 0.79) and submaximal (r = 0.81) OUES/kg with oxygen consumption at peak exercise (VO2peak) and ventilatory anaerobic threshold (VO2VAT) was observed, and a moderate negative correlation with hip circumference (r = -0.46) and body adiposity index (r = -0.50) was also verified. There was no significant difference between maximal and submaximal OUES, showing strong correlations with each other and oxygen consumption (peak and VAT). These results indicate that OUES can be a useful parameter which could be used as a cardiopulmonary fitness index in subjects with severe limitations to perform CPX, as for morbidly obese women.

Effects of a Physical Activity Program on Cardiorespiratory Fitness and Pulmonary Function in Obese Women after Bariatric Surgery: a Pilot Study.

BACKGROUND: In severely obese individuals, reducing body weight induced by bariatric surgery is able to promote a reduction in comorbidities and improve respiratory symptoms. However, cardiorespiratory fitness (CRF) reflected by peak oxygen uptake (VO2peak) may not improve in individuals who remain sedentary post-surgery. The objective of this study was to evaluate the effects of a physical training program on CRF and pulmonary function in obese women after bariatric surgery, and to compare them to a control group. METHODS: Twelve obese female candidates for bariatric surgery were evaluated in the preoperative, 3 months postoperative (3MPO), and 6 months postoperative (6MPO) periods through anthropometry, spirometry, and cardiopulmonary exercise testing (CPX). In the 3MPO period, patients were divided into control group (CG, n = 6) and intervention group (IG, n = 6). CG received only general guidelines while IG underwent a structured and supervised physical training program involving aerobic and resistance exercises, lasting 12 weeks. RESULTS: All patients had a significant reduction in anthropometric measurements and an increase in lung function after surgery, with no difference between groups. However, only IG presented a significant increase (p < 0.05) in VO2peak and total CPX duration of 5.9 mL/kg/min (23.8%) and 4.9 min (42.9%), respectively. CONCLUSIONS: Applying a physical training program to a group of obese women after 3 months of bariatric surgery could promote a significant increase in CRF only in the trained group, yet also showing that bariatric surgery alone caused an improvement in the lung function of both groups.

Ventilatory and Metabolic Response in the Incremental Shuttle and 6-Min Walking Tests Measured by Telemetry in Obese Patients Prior to Bariatric Surgery.

BACKGROUND: Low cardiopulmonary fitness, measured by oxygen uptake peak (VO 2pk), is associated with postoperative complications and mortality. Obese people have difficulty in performing the cardiopulmonary exercise test, which requires maximal exertion. The incremental shuttle walking test (ISWT) and 6-min walking test (6MWT) have been used to assess cardiorespiratory capacity, mortality, and complications in the postoperative phase. However, the physiological response elicited by these tests in obese people is unknown. This study analyzed and compared cardiopulmonary fitness (oxygen uptake [VO2] and CO2 output [VCO2]) in the ISWT and 6MWT in obese adults using a telemetry system. METHODS: Fifteen obese patients (10 women; mean age 39.4 ± 10.1 years; mean body mass index 43.5 ± 6.8 kg/m(2)) with normal forced vital capacity (% FVC 93.7) performed the 6MWT and ISWT in the field in this cross-sectional study. Metabolic (VO 2pk, VCO2) and respiratory (minute ventilation; VE) variables were recorded using telemetry. RESULTS: Obese patients performed the ISWT with an incremental and exponential cardiopulmonary response, with higher VO 2pk (15.4 ± 2.9 ml/kg/min), VCO2 (1.7 ± 0.7 l/min), and VE (51.4 ± 21.3 l/min) than the 6MWT (VO 2pk = 13.2 ± 2.59 ml/kg/min, VCO2 = 1.4 ± 0.6 l/min; VE = 41.2 ± 16.6 l/min (all p < 0.01). They also demonstrated more effort intensity, assessed by VO2, (p = 0.006) and heart rate (p = 0.04) in the ISWT than the 6MWT. In the 6MWT, patients showed a fast rise in ventilatory and metabolic response, reaching a plateau. CONCLUSION: The ISWT test generated superior metabolic and ventilatory stress than the 6MWT and may be more suitable for assessing cardiopulmonary fitness than self-paced tests.