The main objective of this study is to describe the incidence of postoperative residual paralysis (mean train-of-four <90%) when weaning from the ventilator in patients admitted to the Intensive Care Unit (ICU) after elective cardiac surgery. Train-of-four monitoring is a widely used term for the peripheral nerve stimulation used in neuromuscular blockade monitoring. When the patient is ready for weaning from the ventilator, an ICU doctor will perform a measurement of the train-of-four at the thumb with a neuromuscular transmission monitor. Every value below 90% will be considered as residual paralysis and treated appropriately by means of a reversal agent.

Postoperatively, in the ICU, readiness-for-weaning is based on ICU doctor-nurse-driven institutional weaning guidelines: 6 hours after arrival in the ICU, a patient who is normothermic, hemodynamically stable, has normal blood gasses and absence of residual bleeding. The ICU nurse caring for the patient will start weaning the patient from the ventilator, following these departmental guidelines.

Inclusion Criteria:

• patients admitted to the ICU after elective cardiac surgery

Exclusion Criteria:

• emergency cardiac surgery

The participant will still be under sedation at the moment of measuring neuromuscular blockade. The care provider will perform measurements, while the investigator is blinded.