Comparison of train-of-four and posttetanic response as guides for endotracheal intubation in children.

STUDY OBJECTIVE

To evaluate and compare the predictive values of the absence of train-of-four (TOF) or posttetanic response as guides for endotracheal intubation in children.

DESIGN

Prospective controlled study in children.

SETTING

Induction of anesthesia and endotracheal intubation at a university-affiliated hospital.

PATIENTS

Thirty pediatric patients age 1 to 10 years, ASA physical status I, who were undergoing elective surgery were divided into two equal groups.

INTERVENTIONS

Anesthesia was induced with halothane and maintained at 1% inspired concentration. Fifteen children were stimulated with the TOF (2 Hz for 2 seconds) technique and 15 with the twitch-tetanus-twitch sequence. All the patients received atracurium 0.4 mg/kg. Upon abolishment of the TOF or tetanus-twitch sequence, endotracheal intubation was performed and the conditions for intubation were evaluated.

MEASUREMENTS AND MAIN RESULTS

In the group of patients stimulated by the TOF technique, the neuromuscular response was ablated in 1.7 +/- 0.1 minutes, a significantly shorter time than in those stimulated by the tetanus-twitch sequence (4.0 +/- 0.4 minutes; p less than 0.0001). Conditions for intubation did not differ between the two groups.

CONCLUSIONS

Good intubating conditions can generally be counted on when the TOF has disappeared; additional waiting for the disappearance of posttetanic response is unnecessary. The observation that the disappearance of the tetanus-twitch sequence is a good indicator of deep neuromuscular blockade during recovery from atracurium in children cannot be extrapolated to the induction period.