Appropriateness of Age-based Formula to Determine Endotracheal Tube Size in Korean Children / 대한마취과학회지

BACKGROUND: Age-based formulae have been widely used to predict appropriate size of the endotracheal tube (ETT) in children. The objective of this study was to evaluate the effectiveness of formula (internal diameter (ID) (mm) = [age in years + 16]/4) in Korean children. METHODS: Ninety children under 8 years who required intubation with the regular uncuffed ETT were included in the study. Appropriate sizes were to permit a gas leak at 10-25 cmH2O with positive pressure ventilation. Initial intubation was tried with predetermined size and ETT was adjusted to meet this guideline. RESULTS: A range of three tubes around the predicted tube size covered 79 cases (88%), whereas one size predicted by the formula applied to only 29 cases (32%). The selection of ETT which is 0.5 mm larger than the predicted size could allow appropriate intubation in 41 (45.6%) patients. CONCLUSIONS: The age-based formula (ID (mm) = [age in years + 16]/4) could predict the appropriate tube size in less than one third our patients. Therefore, we recommend three sizes be available before endotracheal intubation.

Comparison of Sensory and Motor Nerve Block in Epidural Anesthesia Using a Different Concentrations of Ropivacaine for Cesarean Section / 대한마취과학회지

BACKGROUND: The aim of this study was to evaluate the sensory and motor nerve block achieved by epidural anesthesia using 0.475% ropivacaine and 0.75% ropivacaine. METHODS: Fifty-six patients undergoing cesarean section were randomly allocated to group I (0.75% ropivacaine) or group II (0.475% ropivacaine). We assessed changes in sensory and motor block using the Bromage scale over 180 minutes after epidural anesthesia. The incidence of nausea, vomiting and the total dosage of ephedrine used were also recorded. Sensory changes, motor blockade and the total dosage of ephedrine used were compared using the t-test (P < 0.05). RESULTS: No significant differences were found between the two groups at the sensory block level except at 30 and 60 minutes after epidural anesthesia. However, the motor blockade of group I was significantly more intense than that of group II at 15, 20, 25, 30, 60, 120 and 180 minutes after epidural anesthesia. No significant differences were observed between the two groups in the incidences of nausea, vomiting or the total dosage of ephedrine used. CONCLUSIONS: The use of 0.475% ropivacaine instead of 0.75% ropivacaine in epidural anesthesia for cesarean section did not reduce the incidence of nausea, vomiting or the total dosage of ephedrine used. The sensory block achieved using 0.75% ropivacaine was similar, but the motor blockade achieved using 0.475% ropivacaine was less intense with a shorter duration and an earlier recovery to normal than that of 0.75% ropivacaine. These results suggest that 0.475% ropivacaine may be more useful in epidural anesthesia for cesarean section than 0.75% ropivacaine.