Introduction:
Postoperative residual curarization (PORC) is a common complication but rarely taken into account during the postoperative period. PORC is associated with an increased risk of morbidity and mortality in anesthetized patients. Even small degrees of residual muscle relaxation of the transverse striated muscles can have serious clinical consequences for patients including a decline of upper respiratory tract function or swallowing disorders.

Aim:
The aim of the work is to discuss the problem of PORC, its risk factors and diagnosis, as well as to identify the most common errors, which can be made even by experienced anesthesiologists and can lead to an increased risk of developing this life-threatening complication.

Material and methods:
This work is based on the available literature and the authors’ experience.

Results and discussion:
PORC caused by non-depolarizing neuromuscular blocking agents is a known problem in daily clinical practice. The effects of PORC significantly increase the risk of respiratory complications (hypoxia, pulmonary edema, atelectasis and pneumonia). Patients can report discomfort even with a small degree of residual muscle block above a train of four (TOF) ratio of 0.8. Complete recovery of neuromuscular function does not occur until the TOF ratio is greater or equal to 0.9.

Conclusions:
The primary strategy to avoid residual neuromuscular block and to improve the safety precautions of patients undergoing anesthesia is not by means of clinical evaluation but consistent monitoring of neuromuscular conduction and extubating the patient when the TOF ratio more than 0.9.