Interindividual Variability in Duration of Action of Rocuronium in Pediatric Patients

Muscle relaxants represent an important part of general anesthesia in adult and pediatric patients. Their role is to facilitate intubation and enable some surgical interventions.

At our workplace, monitoring of the depth of neuromuscular blockade is a standard procedure in accordance with the 2017 recommendation of ČSARIM entitled "Principles of Patient Safety in Anesthesiology" \[1,2\]. At present, we mainly use rocuronium. One of the advantages of this non-depolarizing steroidal muscle relaxant with a rapid onset and intermediate duration of action is the existence of the specific antagonist sugammadex.

Given the observational study design, we expect that no informed consent will be required. In pediatric patients undergoing a planned general anesthesia with non-depolarizing muscle relaxants, induction of anesthesia will involve either standard intravenous (an opioid, anesthetic, muscle relaxant) or inhalational agents according to the preference of the anesthesiologist. Standard monitoring during general anesthesia will be carried out including measurement of the depth of neuromuscular blockade (Train of Four, TOF, Avance CS2 machine, relaxometry module, stimulating current of 50 mA) every minute and body temperature monitoring. Subsequently, these parameters including the age-related minimum alveolar concentration of sevoflurane will be documented in the Case Report Form (CRF).

Rocuronium will be administered at a dose according to the Summary of Product Characteristics (SPC) and local expertise. Patient demographic parameters, dose of rocuronium, time of its administration, and time of TOF 1 measurement (= clinical effect, stimulation of the ulnar nerve - adductor pollicis muscle tension) will be documented in the CRF and if there is no need to add further doses of the muscle relaxant, TOF 2, TOF 3, TOF 4, and TOF-R ≥ 0,9 (= time to full recovery from the effect of the non-depolarizing muscle relaxant) will also be registered. In addition, reversal of neuromuscular blockade if applicable and the Aldrete score in the first and fifth minute after extubation will be recorded.

In patients monitored after an intervention in a recovery room, possible complications occurring within at least 30 minutes postoperatively will be documented (desaturation, the need for oxygen therapy, tachycardia \>150 beats per minute, bradycardia \<50 beats per minute, aspiration, sore throat, cough, hoarseness). All patients will be screened for aspiration pneumonia on chest X-ray within the first 24 hours after an intervention.

Eligibility Criteria:
Inclusion Criteria:

* Pediatric patients aged 0 to 18 years admitted for a planned intervention in general anesthesia with orotracheal or nasotracheal intubation and use of the muscle relaxant rocuronium
* ASA score 1 or 2

Exclusion Criteria:

* Patients requiring more types of muscle relaxants during general anesthesia induction
* Patients requiring a rapid sequence induction to general anesthesia
* Neuromuscular disease
* Concomitant medication interfering with the metabolism of muscle relaxants (anticonvulsants, aminoglycosides, polypeptide antibiotics)
* Comorbidities - renal or hepatic disorders
* ASA ≥ 3