Pulmonary function and quality of life in patients with morbid obesity six months after bariatric surgery

Aerobic exercise capacity is normal in obesity with or without metabolic syndrome

BACKGROUND

Obesity might be a cause of limited aerobic exercise capacity. It is often associated with metabolic syndrome (MS) that includes cardiovascular comorbidities as arterial hypertension. Cardiopulmonary exercise testing (CPET) is the gold-standard to assess aerobic capacity and discriminate causes of dyspnea.

AIM

To evaluate aerobic capacity in obesity and if MS or hypertensive treatment impacts on the CPET profile.

METHODS

CPET of 146 obese patients, whom 33 and 31 were matched for MS and antihypertensive medication, were analyzed. VO_2peak (mL/min/Kg) was reported in percentage of predicted value, or, divided by body weight, fat free mass (FFM) or body weight expected for a body mass index of 24 (BMI24).

RESULTS

VO_2peak (20,8 ± 4,4 mL/min/Kg) was normal when expressed in percentage predicted for obesity (111 ± 22%pred) or divided by FFM and weight_BMI24 (33,6 ± 5,6 and 30,6 ± 6,2 respectively). The latter correlated better with maximal work rate (r = 0,7168, p < 0,001). Obese patients showed normal ventilatory efficiency (ventilation to carbon dioxide production slope: 28 ± 4), VO₂ to work rate (10,2 ± 1,6 mLO₂/Watt) and, slightly elevated heart rate to VO₂ slope (4,0 ± 1,1 bpm/mL/min/Kg). Compared to normotensives, hypertensive medicated patients had higher blood pressure at anaerobic threshold (142 ± 23 vs 158 ± 26 mmHg, p = 0,001) but not at maximal exercise (189 ± 31 vs 201 ± 23 mmHg, p = NS), and, had lower actual maximal heart rate (155 ± 23 vs 143 ± 25 bpm, p = 0,03). There was no difference between obese patients with or without MS.

CONCLUSION

Obese people with or without MS present with similar and normal aerobic profile related to the excessive body weight. VO_2peak divided by weight_BMI24 is an easy and clinical meaningful index for obese patients.

Identifying Patients at High Risk of Having Pulmonary Dysfunction Before Laparoscopic Bariatric Surgery and Its Impact on Postoperative Pulmonary Complications

Background: Morbid obesity is associated with variable degrees of pulmonary dysfunction that may predispose to postoperative complications. This study aimed to identify high risk patients to have pulmonary dysfunction before bariatric surgery in terms of age, sex, and body mass index (BMI) and the impact of pulmonary dysfunction on postoperative pulmonary complications. Methods: Prospective database of patients with morbid obesity who underwent bariatric surgery was reviewed. Data on patients' demographics, parameters of pulmonary function tests, and postoperative pulmonary complications were collected. The correlation between patients' age, sex and BMI, and pulmonary function was investigated using Pearson's correlation coefficient test. Results: Ninety-seven patients (82 female) with morbid obesity were included in the study. Twenty-eight (28.9%) patients had pulmonary dysfunction. Patients >40 years had higher odds of pulmonary dysfunction than patients ≤40 years (odds ratio [OR]: 2.54, P = .05). Male patients had significantly higher odds of pulmonary dysfunction than female patients (OR: 2.5, P = .03). Patients with BMI >50 had significantly higher odds of pulmonary dysfunction than patients with BMI <50 (OR: 4.9, P = .002). Patients with pulmonary dysfunction had significantly higher odds of developing pulmonary complications than patients with normal spirometry (OR: 9.13, P = .009). Conclusion: Around 30% of patients undergoing bariatric surgery had pulmonary dysfunction. Pulmonary dysfunction in preoperative spirometry was able to predict postoperative pulmonary complications. Men, patients older than 40 years, and superobese individuals had higher odds of having pulmonary dysfunction and are at higher risk to develop pulmonary complications after bariatric surgery.

The Amount of Weight Loss Six Months after Bariatric Surgery: It Makes a Difference

BACKGROUND

Bariatric surgery, especially Roux-en-Y gastric bypass (RYGB), has become the most frequently used therapy for morbid obesity.

OBJECTIVES

The aim of this study was to examine the effects of surgically induced weight loss on cardiopulmonary function 6 months after the procedure, as well as the effect of such an intervention on well-known risk factors for cardiovascular diseases.

METHODS

This is a cross-sectional study on 66 morbidly obese patients (BMI ≥40 or ≥35 kg/m2 with present comorbidities), comparing their cardiopulmonary function prior to and 6 months after RYGB surgery.

RESULTS

The substantial amount of weight loss (29.80 ± 13.27 kg) after RYGB surgery was associated with significant reduction of comorbidities, especially diabetes and sedentary lifestyle (p = 0.005 and p = 0.002, respectively). Regarding functional capacity, there was significant increase in peak oxygen uptake (VO2 peak, p = 0.003), duration of exercise testing, metabolic equivalents (exercise time and METs, p < 0.001), and in peak O2 pulse. These findings were particularly pronounced in a group of patients who had lost more than 18% of initial weight.

CONCLUSIONS

Reduction of body weight after RYGB surgery is associated with significantly improved cardiorespiratory function 6 months after surgery, especially in patients who lost more than 18% of their initial body weight. In addition, substantial decreases in body weight were also associated with a reduction of cardiovascular risk factors such as diabetes, smoking, hypertriglyceridemia, and sedentary lifestyle.

Minute-Ventilation Variability during Cardiopulmonary Exercise Test is Higher in Sedentary Men Than in Athletes

BACKGROUND

The occurrence of minute-ventilation oscillations during exercise, named periodic breathing, exhibits important prognostic information in heart failure. Considering that exercise training could influence the fluctuation of ventilatory components during exercise, we hypothesized that ventilatory variability during exercise would be greater in sedentary men than athletes.

OBJECTIVE

To compare time-domain variability of ventilatory components of sedentary healthy men and athletes during a progressive maximal exercise test, evaluating their relationship to other variables usually obtained during a cardiopulmonary exercise test.

METHODS

Analysis of time-domain variability (SD/n and RMSSD/n) of minute-ventilation (Ve), respiratory rate (RR) and tidal volume (Vt) during a maximal cardiopulmonary exercise test of 9 athletes and 9 sedentary men was performed. Data was compared by two-tailed Student T test and Pearson´s correlations test.

RESULTS

Sedentary men exhibited greater Vt (SD/n: 1.6 ± 0.3 vs. 0.9 ± 0.3 mL/breaths; p < 0.001) and Ve (SD/n: 97.5 ± 23.1 vs. 71.6 ± 4.8 mL/min x breaths; p = 0.038) variabilities than athletes. VE/VCO2 correlated to Vt variability (RMSSD/n) in both groups.

CONCLUSIONS

Time-domain variability of Vt and Ve during exercise is greater in sedentary than athletes, with a positive relationship between VE/VCO2 pointing to a possible influence of ventilation-perfusion ratio on ventilatory variability during exercise in healthy volunteers.

Assessment of Cardiopulmonary Responses to Treadmill Walking Following Gastric Bypass Surgery

BACKGROUND

Studies that have evaluated cardiopulmonary responses to exercise within the first few months of bariatric surgery have utilized cycle ergometry. However, walking is the most commonly reported mode of both pre- and post-operative PA. The divergent cardiopulmonary responses and metabolic costs of weight-bearing (walking) and non-weight-bearing (cycling) exercises warrant examination of the effects of bariatric surgery on cardiopulmonary responses during walking.

METHODS

Nine women completed a maximal cardiopulmonary exercise test on a treadmill 2 weeks before and 3 months after gastric bypass surgery (GBS). Heart rate (HR), oxygen uptake (VO₂), oxygen pulse (O₂-p), and time to fatigue were compared before and after surgery and between the GBS group and a comparison group of 12 normal-weight (NW) women who completed the same exercise testing protocol.

RESULTS

Time to fatigue increased by ~140 s following GBS (p = 0.018). No other parameter improved during maximal exercise from pre- to post-surgery. Body weight- and fat-free mass-corrected VO₂ and O₂-p at peak exercise differed between the GBS and NW groups before surgery, while only weight-corrected values were different following surgery. These differences disappeared after controlling for body fat percentage.

CONCLUSION

We have demonstrated that weight loss alone was not sufficient to improve select cardiopulmonary fitness measures during treadmill walking in obese females 3 months after GBS. However, we did observe a significant overall improvement in exercise capacity as the GBS group was able to exercise longer, presumably due to significant reductions in body mass and a subsequent reduced metabolic cost of walking.

POSTOPERATIVE EFFECT OF PHYSICAL THERAPY RELATED TO FUNCTIONAL CAPACITY AND RESPIRATORY MUSCLE STRENGTH IN PATIENTS SUBMITTED TO BARIATRIC SURGERY

Background

Respiratory physiotherapy plays an important role preventing complications in bariatric surgery.

Aim

To assess the effects of out-patient physiotherapy during post-operative period through respiratory pressures and functional capacity in individuals submitted to bariatric surgery.

Method

A prospective longitudinal and controlled study was done in adults with body mass index (BMI) equal or greater than 40 kg/m², who have been submitted to bariatric surgery. They were divided into two groups: intervention-group, who performed out-patient physiotherapy twice a week, from thirty to sixty days after surgery; and the control-group, who only followed home instructions. Both groups were evaluated before surgery and sixty days after surgery through manovacuometry, six-minute walk test and the Borg Scale of perceived exertion.

Results

Twenty participants were included the intervention-group and twenty-three in the control-group. Both groups had significant and similar weight loss after surgery. The manovacuometry presented no differences comparing pre- and post-surgery and in the comparison between the groups. The result of the six-minute walk test for the intervention-group increased by 10.1% in the post-operative period in relation to pre-. The Borg scale of perceived exertion in the intervention-group in pre-surgery decreased by 13.5% in the post-surgery compared to pre-surgery. In the control-group there was no difference comparing pre- and post-operative values, as in the comparison with the intervention-group.

Conclusion

The low-intensity exercise program, carried out between the 30th and the 60th day after bariatric surgery provided better functional capacity; did not change respiratory muscle strength; and improved the perceived exertion rate.

[The profile of patients undergoing bariatric surgery in the Brazilian Unified National Health System: a systematic review]

Nearly one million Brazilians were morbidly obese in 2013. Bariatric surgery is an option for sustained weight loss, and the Brazilian Unified National Health System (SUS) had provided 50,000 such procedures as of 2014. The SUS database does not provide anthropometric and comorbidity data on these patients, so the aim of the current study was to perform a systematic review to assess the profile of SUS patients that underwent bariatric surgery from 1998 to 2014. The MEDLINE, LILACS, SciELO, and Scopus databases were searched, and the methodological quality of the included articles was assessed. Of the 1,591 identified studies, 39 were selected, 95% of which were observational. Patients had a mean age of 41.4 years and mean body mass index of 48.6kg/m2; 21% were males, 61% hypertensive, 22% diabetics, and 31% presented sleep apnea. When compared to international study samples, SUS patients showed similar a anthropometric profile and comorbidities but higher prevalence of hypertension. The studies' low methodological quality suggests caution in interpreting the results.

Estudo do sono e função pulmonar em pacientes obesos mórbidos

INTRODUÇÃO: A obesidade acarreta uma série de alterações na fisiologia respiratória e no sono. Seu tratamento tem como objetivo a melhora da saúde e da qualidade de vida. OBJETIVO: Avaliar a função pulmonar e o sono em indivíduos obesos mórbidos pré-cirurgia bariátrica. MATERIAIS E MÉTODOS: Participaram deste estudo 38 pacientes, recrutados em dois serviços de cirurgia bariátrica e encaminhados ao Laboratório de Sono da Universidade Nove de Julho, São Paulo, Brasil. Os critérios de inclusão foram: obesos mórbidos, IMC entre 40 kg/m² e 50 kg/m² e IMC entre 35 kg/m² a 39,9 kg/m² se associados a comorbidades. RESULTADOS: A média de idade foi de 42 ± 10, o índice de massa corpórea médio foi de 50,09 ± 7,64. A média da circunferência abdominal foi de 132,48 ±11,07 e 134,31 ± 16,26 e de pescoço foi 42,34 ± 2,08 e 44,48 ± 3,67, respectivamente para mulheres e homens. As pressões máximas inspiratórias foram 57,57 ± 18,93 e 60,6 ± 3,72 e máximas expiratórias 56,63 ± 16,68 e 60 ± 18,52, para mulheres e homens respectivamente. O sono do movimento rápido dos olhos apresentou-se com média de 16,93 ± 13,61 e a saturação mínima da oxi-hemoglobina foi de 79,33 ± 10,26 durante o sono. Em 44,74% dos casos examinados, foram observadas alterações na Escala de Sonolência de Epworth (ESE); e em 76,3% ficou confirmada a presença de síndrome da apneia obstrutiva do sono (SAOS). CONCLUSÃO: Foram observadas alterações nas pressões máximas ventilatórias, na estrutura do sono associadas a considerável dessaturação noturna da oxi-hemoglobina, o que evidencia alta prevalência de SAOS nos pacientes obesos mórbidos.

Sleep study, respiratory mechanics, chemosensitive response and quality of life in morbidly obese patients undergoing bariatric surgery: a prospective, randomized, controlled trial

BACKGROUND

Obesity is a major public health problem in both developed and developing countries alike and leads to a series of changes in respiratory physiology. There is a strong correlation between obesity and cardiopulmonary sleep disorders. Weight loss among such patients leads to a reduction in these alterations in respiratory physiology, but clinical treatment is not effective for a long period of time. Thus, bariatric surgery is a viable option.

METHODS/DESIGN

The present study involves patients with morbid obesity (BMI of 40 kg/m2 or 35 kg/m2 to 39.9 kg/m2 with comorbidities), candidates for bariatric surgery, screened at the Santa Casa de Misericórdia Hospital in the city of Sao Paulo (Brazil). The inclusion criteria are grade III morbid obesity, an indication for bariatric surgery, agreement to participate in the study and a signed term of informed consent. The exclusion criteria are BMI above 55 kg/m2, clinically significant or unstable mental health concerns, an unrealistic postoperative target weight and/or unrealistic expectations of surgical treatment. Bariatric surgery candidates who meet the inclusion criteria will be referred to Santa Casa de Misericórdia Hospital and will be reviewed again 30, 90 and 360 days following surgery. Data collection will involve patient records, personal data collection, objective assessment of HR, BP, neck circumference, chest and abdomen, collection and analysis of clinical preoperative findings, polysomnography, pulmonary function test and a questionnaire on sleepiness.

DISCUSSION

This paper describes a randomised controlled trial of morbidly obese patients. Polysomnography, respiratory mechanics, chemosensitive response and quality of life will be assessed in patients undergoing or not undergoing bariatric surgery.

TRIAL REGISTRATION

The protocol for this study is registered with the Brazilian Registry of Clinical Trials - ReBEC (RBR-9k9hhv).