Evaluation of the Solitary Pulmonary Nodule.

A solitary pulmonary nodule is a common radiologic finding that is often discovered incidentally and may require significant workup to establish a definitive diagnosis. A solitary pulmonary nodule is a well-circumscribed round lesion measuring up to 3 cm in diameter and surrounded by aerated lung. Once a nodule is discovered, clinical and radiologic features and quantitative models can be used to determine the likelihood of malignancy. Evaluation is guided by nodule size and assessment of probability of malignancy. Surgical resection or nonsurgical biopsy should be performed in patients with solid or subsolid solitary pulmonary nodules that show clear growth on serial imaging. Solid solitary pulmonary nodules that have been stable for at least two years typically do not need further evaluation. The workup for patients with solid solitary pulmonary nodules measuring 8 mm or greater in diameter, nodules measuring less than 8 mm in diameter, and subsolid nodules should be guided by the probability of malignancy, imaging results, and the risks and benefits of different management strategies. Management should be individualized according to patient values and preferences. Medicare now covers lung cancer screening with low-dose computed tomography for high-risk patients 55 to 77 years of age at institutions that can provide a comprehensive approach to the management of solitary pulmonary nodules.

Normobaric Hypoxia Exposure During Treadmill Aerobic Exercise After Stroke: A Safety and Feasibility Study.

OBJECTIVE: To evaluate the safety and feasibility of performing treadmill aerobic exercise in moderate normobaric hypoxia among chronic hemiparetic stroke survivors. DESIGN: Observational study using convenience sampling. SETTING: Research laboratory in a tertiary rehabilitation hospital. PARTICIPANTS: Chronic hemiparetic stroke survivors who could walk at least 10-m with or without assistance and had no absolute contraindications to exercise testing. INTERVENTION: Participants (three male and four female) were asked to complete three normobaric hypoxia exposure protocols within a single session. First, they were passively exposed to normobaric hypoxia through gradual reductions in the fraction of inspired oxygen (FIO2 = 20.9, 17.0, and 15.0%) while seated (5-min at each level of FIO2). Participants were then exposed to the same reductions in FIO2 during constant-load exercise performed on a treadmill at 40% of heart rate reserve. Finally, participants completed 20-min of exercise while intermittently exposed to moderate normobaric hypoxia (5 × 2-min at FIO2 = 15.0%) interspaced with 2-min normoxia intervals (FIO2 = 20.9%). OUTCOME MEASURES: The primary outcome was occurrence of adverse events, which included standardized criteria for terminating exercise testing, blood oxygen saturation (SpO2) <80%, or acute mountain sickness score >2. The increased cardiovascular strain imposed by normobaric hypoxia exposure at rest and during exercise was evaluated by changes in SpO2, heart rate (HR), blood pressure, and rating of perceived exertion (RPE). RESULTS: One participant reported mild symptoms of nausea during exercise in normobaric hypoxia and discontinued participation. No other adverse events were recorded. Intermittent normobaric hypoxia exposure was associated with reduced SpO2 (MD = -7.4%, CI: -9.8 to -5.0) and increased HR (MD = 8.2, CI: 4.6 to 11.7) compared to intervals while breathing typical room air throughout the 20-min constant-load exercise period. The increase in HR was associated with a 10% increase in relative effort. However, reducing FIO2 had little effect on blood pressure and RPE measurements. CONCLUSION: Moderate normobaric hypoxia appeared to be a safe and feasible method to increase the cardiovascular strain of submaximal exercise in chronic hemiparetic stroke survivors. Future studies evaluating the effects of pairing normobaric hypoxia exposure with existing therapies on secondary prevention and functional recovery are warranted.

Assistance using adaptive oscillators: robustness to errors in the identification of the limb parameters.

This paper provides a robustness analysis of the method we recently developed for rhythmic movement assistance using adaptive oscillators. An adaptive oscillator is a mathematical tool capable of extracting high-level features (i.e. amplitude, frequency, offset) of a quasi-sinusoidal measured movement, a rhythmic flexion-extension of the elbow in this case. By the use of a simple inverse dynamical model, the system can predict the torque produced by a human participant, such that a fraction of this estimated torque is fed back through a series elastic actuator to provide movement assistance. This paper objectives are twofold. First, we introduce a new 1 DOF assistive device developed in our lab. Second, we derive model-based predictions and conduct experimental validations to measure the variations in movement frequency as a function of the open parameters of the inverse dynamical model. As such, the paper provides an estimation of the robustness of our method due to model approximations. As main result, the paper reveals that the movement frequency is particularly robust to errors in the estimation of the damping coefficient. This is of high interest for the applicability of our approach, this parameter being in general the most difficult to identify.