Ricerc@Sapienza

BACKGROUND: The diaphragm is the most important respiratory muscle in humans, and the close relationship between inspired volume and diaphragmatic movement in normal subjects has led to investigations into diaphragmatic activity using ultrasound, during spontaneous breathing and sedative drug infusion.
METHODS: A total of 36 consecutive patients undergoing diagnostic procedures under deep propofol sedation were studied. Ultrasound measurements included the following: diaphragmatic thickening end-inspiration (TEI) and end-expiration (TEE). Diaphragmatic thickening fraction (DTF) was calculated from [(TEI - TEE) / TEE] at various time points (at T0 basal; at T1 during propofol infusion; at T2 awakening). Oxygen was administered at 4 L/min, and oxygen saturation (SpO2), end tidal CO2 (EtCO2) and respiratory rate (RR) were recorded.
RESULTS: TEI, and TEE decreased by 26.7% and 17.4%, respectively, during propofol infusion (T0 versus T1) (P CONCLUSIONS: Our study showed that deep propofol sedation affects muscle activity in healthy patients. While diaphragmatic strength decreased during sedation, there was no clinically relevant effect on SpO2. The study also confirmed that ultrasound is suitable for measuring diaphragm activity during a normal clinical procedure.