a nurse is performing a shift assessment on an elderly client who is recovering after surgery for a hip fracture. the client reports chest pain, has an increased heart rate, and increased respiratory rate. the nurse further notes that the client is febrile and hypoxic, coughing, and producing large amounts of thick, white sputum. the nurse recognizes that this is a medical emergency and calls for assistance, recognizing that this client is likely demonstrating symptoms of what complication?