Mayo Clinic
The purpose of this study is to evaluate opioid dose effects on the ability of the diaphragm muscle to generate higher force behaviors.
Inclusion Criteria: \- Adult male and female patients undergoing lower extremity orthopedic surgery at the study institutions (St. Mary Hospital and Rochester Methodist Hospital within the Mayo Clinic Rochester hospital system). Exclusion Criteria: * Patients who refuse research participation. * Patients who are pregnant. * Patients with known pulmonary pathology (COPD, asthma requiring routine treatment).
Three different fentanyl doses (used for sedation) will be evaluated on their effects on shear wave elastography (SWE) and breathing