Mechanical Unloading for Obesity in Aging
Recruiting in Palo Alto (17 mi)
Age: 65+
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: University of Texas Southwestern Medical Center
Must not be taking: Exercise capacity drugs
Disqualifiers: Smoking, Heart disease, Hypertension, Asthma, others
No Placebo Group
Approved in 1 jurisdiction
Trial Summary
What is the purpose of this trial?The overall objective of this application is to investigate the effects of obesity on lung function, exercise tolerance, and DOE in older obese adults as compared with older adults without obesity, using a novel probe for mechanically unloading the thorax at rest and during exercise. The investigators will use 1) continuous negative cuirass pressure, and 2) assisted biphasic cuirass ventilation to decrease obesity-related effects in older obese adults. Our approach will be to examine respiratory function, exercise tolerance, and DOE with and without mechanical unloading in older obese men and women (65-75 yr), including those with respiratory symptoms (defined by a score of 1 or 2 on the modified Medical Research Council Dyspnea Scale), as compared with older adults without obesity.
Specific Aims: The investigators will test the following hypotheses in older adults with and without obesity:
Aim 1) Obesity will decrease respiratory function but to a greater extent in older obese adults with respiratory symptoms, (as evidenced by altered pulmonary function and breathing mechanics at rest); Aim 2) Obesity will decrease exercise tolerance (as evidenced by peak V•O2 in ml/min/kg, i.e., physical fitness), but not cardiorespiratory fitness (as evidenced by peak V•O2 in % of predicted based on ideal body wt), except in older obese adults with respiratory symptoms where both may be reduced during graded cycle ergometry.
Aim 3) Obesity will increase DOE but to a greater extent in older obese adults with respiratory symptoms as evidenced by increased ratings of perceived breathlessness (sensory \& affective dimensions) during exercise.
Aim 4) Mechanical unloading of the thorax will improve respiratory function, submaximal exercise tolerance, and DOE in older obese adults, but to a greater extent in older obese adults with respiratory symptoms.
Do I have to stop taking my current medications for the trial?
The trial requires that you do not take any current medications that may interfere with exercise capacity. If you are on such medications, you may need to stop them to participate.
What data supports the idea that Mechanical Unloading for Obesity in Aging is an effective treatment?
The available research shows that mechanical ventilation strategies, which are similar to Mechanical Unloading for Obesity in Aging, can improve lung function in obese patients. For example, using specific ventilatory settings helps improve lung volumes and gas exchange, which are crucial for better breathing. Additionally, non-invasive ventilation has been shown to improve respiratory parameters and survival rates in morbidly obese patients with breathing difficulties. These findings suggest that similar approaches, like Mechanical Unloading, could be effective in managing obesity-related respiratory issues.
12345What safety data exists for mechanical unloading treatments for obesity in aging?
The provided research abstracts do not directly address the safety data for mechanical unloading treatments such as Mechanical Unloading of the Thorax, Continuous Negative Cuirass Pressure, or Assisted Biphasic Cuirass Ventilation. Instead, they focus on the effects of positive end-expiratory pressure and mechanical ventilation in obese patients, particularly in ICU settings. These studies explore respiratory mechanics, lung recruitment, and ventilator-induced lung injury in morbidly obese patients, but do not provide specific safety data for the treatments in question.
12467Is the treatment 'Mechanical unloading of the Thorax' a promising treatment for obesity in aging?
Yes, mechanical unloading of the thorax, which helps with breathing by reducing the effort needed to breathe, shows promise as a treatment. It can improve breathing efficiency and reduce the strain on the chest, potentially benefiting people with obesity.
128910Eligibility Criteria
This trial is for healthy older adults aged 65-75 with normal lung function and specific body fat percentages (men: 30-50%, women: 35-55%). Participants should be nonsmokers, without significant mental illness, uncontrolled hypertension, serious health conditions affecting exercise capacity, metabolic disorders like diabetes, or a history of substance abuse. Only postmenopausal women are eligible.Inclusion Criteria
Nonsmokers with no history of smoking
I can exercise without being limited by a physical condition.
I am a postmenopausal woman.
+14 more
Exclusion Criteria
Individuals participating in regular vigorous conditioning exercise more than two times per week
Subjects with an exceedingly high exercise capacity (greater than 2 SD of predicted)
I am a woman who has not gone through menopause.
+4 more
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
2-4 weeks
Baseline Assessment
Initial assessment of lung function, exercise tolerance, and DOE using various measurements and questionnaires
1 week
1 visit (in-person)
Intervention
Participants undergo mechanical unloading of the thorax using continuous negative cuirass pressure and assisted biphasic cuirass ventilation
6 weeks
4 visits (in-person)
Follow-up
Participants are monitored for changes in respiratory function, exercise tolerance, and DOE after intervention
4 weeks
2 visits (in-person)
Participant Groups
The study tests if mechanical unloading of the thorax using an external cuirass can improve lung function and exercise tolerance in obese older adults. It compares respiratory functions and breathlessness during rest and exercise between those with obesity-related respiratory symptoms and those without.
1Treatment groups
Experimental Treatment
Group I: Interventional ArmExperimental Treatment1 Intervention
Older group of adults (65-75 yrs). Everyone enrolled uses the 'intervention'/ external cuirass - mechanical unloading of thorax
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
Institute for Exercise and Environmental Medicine, UT Southwestern and Texas Health ResourcesDallas, TX
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Who Is Running the Clinical Trial?
University of Texas Southwestern Medical CenterLead Sponsor
References
Recruitment Maneuvers and Positive End-Expiratory Pressure Titration in Morbidly Obese ICU Patients. [2022]The approach to applying positive end-expiratory pressure in morbidly obese patients is not well defined. These patients frequently require prolonged mechanical ventilation, increasing the risk for failed liberation from ventilatory support. We hypothesized that lung recruitment maneuvers and titration of positive end-expiratory pressure were both necessary to improve lung volumes and the elastic properties of the lungs, leading to improved gas exchange.
Pleural Pressure Targeted Positive Airway Pressure Improves Cardiopulmonary Function in Spontaneously Breathing Patients With Obesity. [2022]Label="BACKGROUND">Increased pleural pressure affects the mechanics of breathing of people with class III obesity (BMI > 40 kg/m2).
Mechanical ventilation in obese patients. [2022]Recent data show an alarming increasing trend in obesity around the world. Mechanical ventilation in this population requires specific ventilatory settings due to the mechanical and inflammatory alterations observed in obesity. In this line, end-expiratory lung volume is decreased, leading to impairment in the mechanics of the respiratory system, lung and chest wall as well as gas-exchange. Furthermore, the inflammatory process acts on distal airways, increasing airway responsiveness, or on pulmonary endothelium cells, increasing the molecules related to the adherence of inflammatory cells. In order to reduce lung stress and strain, as well as minimize the risk of ventilator associated lung injury, mechanical ventilation management should be conducted with the following strategies: 1) stepwise recruitment maneuver before positive end-expiratory pressure application, which requires titration according to respiratory system dynamic compliance; and 2) tidal volume (VT) titration according to inspiratory capacity. In summary, the overall objective is to ensure an adequate setting of ventilator parameters in order to minimize the inflammatory impact already present in obese patients as well as prevent further lung damage.
Effects of sitting position and applied positive end-expiratory pressure on respiratory mechanics of critically ill obese patients receiving mechanical ventilation*. [2022]To evaluate the extent to which sitting position and applied positive end-expiratory pressure improve respiratory mechanics of severely obese patients under mechanical ventilation.
Managing acute respiratory decompensation in the morbidly obese. [2022]Morbid obesity adversely affects respiratory physiology, leading to reduced lung volumes, decreased lung compliance, ventilation perfusion mismatch, sleep-disordered breathing and the impairment of ventilatory control, and neurohormonal and neuromodulators of breathing. Therefore, morbidly obese subjects are at increased risk of various pulmonary complications that can present either acutely or chronically. Respiratory failure is one of the most common pulmonary complications related to morbid obesity. Both acute hypoxaemic and hypercapnic respiratory failure are more common among obese patients. The management pathway of respiratory failure depends, to a large extent, on the underlying cause, primarily due to the diversity of the underlying triggering diseases, the pathophysiology and the prognosis associated with each disease. Morbidly obese patients with hypoventilation have an increased risk of acute hypercapnic respiratory failure. Early diagnosis of this disorder and the application of non-invasive ventilation in this group of patients have been shown to improve respiratory parameters, decrease the need for invasive mechanical ventilation and improve survival. Invasive ventilation remains the last life-saving procedure in patients with respiratory failure who do not respond to non-invasive measures. However, due to the abnormal respiratory physiology in obese patients, special precautions are required during intubation, mechanical ventilation and weaning.
Expiratory flow limitation in morbidly obese postoperative mechanically ventilated patients. [2013]Although obesity promotes tidal expiratory flow limitation (EFL), with concurrent dynamic hyperinflation (DH), intrinsic PEEP (PEEPi) and risk of low lung volume injury, the prevalence and magnitude of EFL, DH and PEEPi have not yet been studied in mechanically ventilated morbidly obese subjects. In 15 postoperative mechanically ventilated morbidly obese subjects, we assessed the prevalence of EFL [using the negative expiratory pressure (NEP) technique], PEEPi, DH, respiratory mechanics, arterial oxygenation and PEEPi inequality index as well as the levels of PEEP required to abolish EFL. In supine position at zero PEEP, 10 patients exhibited EFL with a significantly higher PEEPi and DH and a significantly lower PEEPi inequality index than found in the five non-EFL (NEFL) subjects. Impaired gas exchange was found in all cases without significant differences between the EFL and NEFL subjects. Application of 7.5 +/- 2.5 cm H2O of PEEP (range: 4-16) abolished EFL with a reduction of PEEPi and DH and an increase in FRC and the PEEPi inequality index but no significant effect on gas exchange. The present study indicates that: (a) on zero PEEP, EFL is present in most postoperative mechanically ventilated morbidly obese subjects; (b) EFL (and concurrent risk of low lung volume injury) is abolished with appropriate levels of PEEP; and (c) impaired gas exchange is common in these patients, probably mainly due to atelectasis.
Elastic Power of Mechanical Ventilation in Morbid Obesity and Severe Hypoxemia. [2023]To minimize ventilator-induced lung injury, the primary clinical focus is currently expanding from measuring static indices of the individual tidal cycle (eg, plateau pressure and tidal volume) to more inclusive indicators of energy load, such as total power and its elastic components. Morbid obesity may influence these components. We characterized the relative values of elastic subcomponents of total power (ie, driving power and dynamic power) in subjects with severe hypoxemia, morbid obesity, or their combination.
Effects of respiratory mechanical unloading on thoracoabdominal motion in meconium-injured piglets and rabbits. [2019]Impaired pulmonary mechanics can cause chest wall distortion (CWD) so that work of breathing is dissipated in deforming the rib cage. We hypothesized that respiratory mechanical unloading as a technique of assisted mechanical ventilation would reduce CWD in animals with injured lungs. We studied five piglets and five adult rabbits to test across different ages and chest configurations. As a result of intratracheal meconium instillation, lung compliance decreased from 21 (median; range 17-35) to 9.5 (6.7-14) mL/kPa/kg in rabbits and from 26 (18-31) to 7.9 (4.9-11) in piglets. Airway resistance increased from 5.0 (4.6-6.1) to 6.9 (5.8-7.9) kPa/L/s in rabbits only. Respiratory inductive plethysmography was used to measure the phase shift between the rib cage and abdominal compartment movements and the total compartmental displacement ratio. We aimed at unloading at least three-fourths of lung elastance in all animals and 2.0 kPa/L/s of resistance in rabbits. Elastic unloading decreased the phase shift in all but one animal. It reduced the total compartmental displacement ratio from 1.27 (1.14-3.73) to 1.16 (1.02-1.82) in piglets and from 1.77 (1.45-5.24) to 1.37 (1.11-4.78) in rabbits. The inspiratory rib cage expansion increased, whereas abdominal expansion did not. The tidal esophageal pressure deflection decreased. Tidal volume increased, whereas respiratory rate remained unaffected so that the partial pressure of arterial CO2 decreased. Resistive unloading as an adjunct to elastic unloading further reduced CWD and induced a more rapid, shallower breathing. We conclude that respiratory unloading as a mechanical support to spontaneous breathing reduces CWD. We speculate that the decrease in CWD increases ventilatory efficiency for a given diaphragmatic effort.
Assisted mechanical ventilation using elastic unloading: a study in cats with normal and injured lungs. [2008]Elastic unloading [otherwise known as negative ventilator compliance (Cv) or proportional assist ventilation] is a new mode of assisted mechanical ventilation. The ventilator continuously measures the volume of spontaneous breathing (V) and adjusts the pressure at the airway opening in proportion to V. The quotient of pressure above the baseline end-expiratory level per unit of V (the gain of the assist) is constant at any point in time and can be preset. The apparatus used for this study can also generate elastic loading (positive Cv) by decreasing the pressure at the airway opening in proportion to V. This might be useful during the weaning process. This study compares measured values of total compliance of the combined lung-respirator system (Ctot) with values predicted according to theory, where 1/Ctot = 1/Cv + 1/Cl with Cl being the lung compliance. Respiratory mechanical data were derived from esophageal pressure and airflow in eight anesthetized, intubated, spontaneously breathing cats. Different Cv levels were set on the ventilator both before and after lung injury with xanthine oxidase. The difference (mean +/- SD) between the measured and predicted Ctot was 1.4 +/- 21.4% (healthy lungs) and -11.6 +/- 14.1% (injured lungs) during unloading and 2.5 +/- 7.5% (healthy lungs) during elastic loading. An elevation of Ctot decreased the expiratory airflow. Tidal volume increased slightly in healthy lungs and arterial PCO2 decreased. We conclude that the effects of Cv on the total compliance of the combined lung-respirator system can accurately be predicted.
Effective Ventilation Strategies for Obese Patients Undergoing Bariatric Surgery: A Literature Review. [2022]Obesity causes major alterations in pulmonary mechanics. Obese patients undergoing bariatric surgery present mechanical ventilation-related challenges that may lead to perioperative complications. Databases were systematically searched for clinical trials of ventilation maneuvers for obese patients and bariatric surgery. Thirteen randomized controlled trials were selected. The quality of the studies was evaluated with the Critical Appraisal Skills Programme tool, and a matrix was developed to present the essential components of the studies. Eight strategies of ventilation maneuvers were identified. Recruitment maneuvers followed by positive end-expiratory pressure (PEEP) consistently demonstrated effectiveness in obese patients undergoing bariatric surgery. Pressure-controlled ventilation and volume-controlled ventilation did not differ significantly in their efficacy. Noninvasive positive pressure ventilation (NIPPV) during induction was effective in preventing atelectasis and increasing the duration of safe apnea. Equal ratio ventilation can be a useful ventilation strategy. Recruitment maneuvers followed by PEEP are effective ventilation strategies for obese patients undergoing bariatric surgery. During induction, NIPPV provides further benefit. Future studies are needed to examine the postoperative effects of recruitment maneuvers with PEEP as well as the efficacy and safety of equal ratio ventilation.