Background/Objectives: Point-of-care lung ultrasonography (LUS) represents an accurate diagnostic tool in older patients with respiratory failure. The integration of LUS with ultrasonographic assessment of diaphragm thickness and excursion, right vastus lateralis (RVL) muscle thickness and cross-sectional area (CSA) could provide real-time information on frailty and sarcopenia. The primary aim of this proof-of-concept prospective study was to evaluate clinical correlates of thoracic, diaphragmatic, and muscular ultrasound to characterize the associations between frailty, respiratory failure, and sarcopenia in older patients hospitalized for acute respiratory complaints. Methods: Each of 52 participants (age median 84, IQR 80–89 years old) underwent integrated LUS, diaphragm and RVL ultrasound examination upon admission (T0) and after 72 h of hospitalization (T1). LUS score was used to estimate lung interstitial syndrome severity. Diaphragm excursion, thickness, RVL thickness and CSA were measured following a standardized protocol. Frailty was assessed with the PC-FI (Primary Care-Frailty Index). Results: All patients exhibited multifactorial causes of respiratory symptoms. The LUS score on T0 predicted 3-month rehospitalization. Frail patients exhibited higher LUS scores on T1. Diaphragm excursion on T0 was reduced in patients with COPD and heart failure and in those developing delirium during hospitalization. Diaphragm excursion on T1 was negatively associated with PC-FI. Diaphragm thickness, RVL thickness, and CSA exhibited a positive association with obesity. Right vastus lateralis CSA on T1, however, was also negatively associated with PC-FI. Conclusions: Integrated lung, diaphragm, and RVL ultrasound shows clinical correlations with several aspects of frailty that may help to improve the management of geriatric patients with respiratory illness.
