Accuracy of train of four ratio and ultrasound derived diaphragm excursion as an indicator of reversal of neuromuscular blockade

General anaesthesia commonly involves the use of neuromuscular blocking drugs, but residual neuromuscular paralysis in the postoperative period remains a significant cause of morbidity and mortality. Traditional qualitative assessments such as sustained head lift and hand grip are unreliable, with studies showing up to 60 percent of patients experiencing postoperative residual curarization . The 2023 ASA guidelines emphasize that clinical assessment alone is insufficient, recommending quantitative monitoring such as the Train-of-Four ratio, with a TOF more than or equal to 0.9 indicating adequate recovery. However, TOF monitoring has limitations, including the need for specialized equipment, baseline calibration, and patient discomfort.

Ultrasound of the diaphragm has recently gained attention as a non-invasive, real-time tool to assess diaphragmatic function through parameters such as diaphragmatic excursion, which reflects contractility and strength. Neostigmine, the most commonly used reversal agent, can variably affect diaphragmatic performance, and inappropriate dosing may paradoxically worsen muscle weakness.

This study aims to evaluate the feasibility and accuracy of ultrasound-derived diaphragmatic excursion as a surrogate marker for assessing neuromuscular recovery compared with the gold-standard TOF ratio. By correlating ultrasound findings with TOF values following neostigmine reversal 0.04 mg per kg. The study seeks to determine whether diaphragmatic ultrasound can serve as a practical, reliable, and less painful alternative for predicting residual neuromuscular blockade and guiding safe extubation, ultimately improving postoperative respiratory outcomes.