Residual neuromuscular block (RNMB) is frequent in the immediate postoperative period and is a source of complications, mainly respiratory. The incidence is variable due to multiple factors. In Spain the incidence is unknown.

The investigators hypothesize that a number of patients in the postanesthesia care unit (PACU) present with RNMB after general anesthesia using intermediate action neuromuscular block agents (NMBA).

The main objective is to know the incidence of RNMB in Spanish hospitals. Secondary objectives are to observe the possible relationship with other pre- and intraoperative factors.

Residual neuromuscular block (RNMB) is frequent in the immediate postoperative period and is a source of complications, mainly respiratory. This includes recovery delay or hospital discharge delays, respiratory insufficiency or infections, unforeseen ICU admissions, and prolonged ICU stays.

The incidence is variable due to multiple factors. Age, gender, surgery, NMBA type and doses, temperature, medications, etc.

In several studies it has been found and incidence between 6-80%. Few studies have been focused in evaluating the incidence in the whole country, as representing a global anesthesia practice. In Spain the incidence is unknown.

The investigators hypothesize that a number of patients in the postanesthesia care unit (PACU) present with RNMB after general anesthesia using intermediate action NMBA.

The main objective is to know the incidence of RNMB in Spanish hospitals, by means of an observational cross-sectional multicenter study .

Secondary objectives are to observe the possible relationship with other pre- and intraoperative factors.

Inclusion Criteria:

• Patients >18 years-old
• General anesthesia with non-depolarizing NMBA
• Transferred extubated on spontaneous ventilation to the PACU

Exclusion Criteria:

• American Society of Anesthesiologists physical status IV-V
• emergency and cardiac surgery
• patients unable to respond adequately at the moment of pre- or postoperative evaluation (psychiatric diseases, excessive somnolence, agitation, etc.)
• noncompensated diabetes mellitus or diabetic neuropathy
• symptomatic severe hypothyroidism (or untreated), or scheduled for total thyroidectomy
• chronic or acute renal insufficiency
• severe hepatopathy (Child-Pugh B, C)
• intraoperative blood transfusion >3 blood units
• intraoperative maintained arterial hypotension
• arrival to the PACU intubated or with instrumented airway (including surgical)
• pre- or perioperative drugs intake affecting the neuromuscular transmission
• neuromuscular diseases affecting the physiology of the neuromuscular system

Surgical patients under general anesthesia