Verification of Appropriate Insertion Depth of Endotracheal Tube Placement

Interventions: Other: determination by auscultation
Other: determination by ultrasound

Brief Summary: The investigators are trying to evaluate the efficacy of ultrasonographic determination of depth of endotracheal tube placement in infants and young children by using the pleural sliding sign.

Detailed Description: It is difficult to determine the adequate depth of endotracheal tube placement in infants and young children. It is usually determined by an equation according to the patient's age (12 + age/2, cm) or auscultation method. The auscultation method is to intentionally place the tip of the endotracheal tube into the right main stem bronchus and then withdraw it until breath sounds are equal. The tube is fixed 1 or 2 cm proximal to the point where breath sounds become equal. However, in small children or infant, as the breadth sound in unilateral lung transmits the contralateral lung field and is often difficult to listen in a noisy operation room, it is often difficult to determine the depth by auscultation method. Pleural sliding sign, or sliding lung sign is a ultrasonographic finding that the visceral pleura moves against the parietal pleura. It is used to identify whether the lung is ventilated by ultrasound. The investigators are trying to use this pleural sliding sign to determine the depth of endotracheal tube, and compare this method with auscultation method.

Recruitment & Eligibility

Inclusion Criteria

Infants or young children (less than body weight of 20 kg) undergoing elective surgery (general surgery, urology, plastic surgery, cardiac surgery) under general anesthesia with endotracheal intubation

Exclusion Criteria

Arm && Interventions

Group	Intervention	Description
Auscultation group	determination by auscultation	The depth of endotracheal tube placement is determined by auscultation.
Ultrasonography group	determination by ultrasound	The depth of placement of endotracheal tube placement is determined by ultrasonographic finding of pleural sliding sign.

Primary Outcome Measures

Name	Time	Method
the incidence of inadequate depth of endotracheal tube placement by flexible brochoscopy after intubation	3 minutes after intubation	the incidence of inadequate depth of endotracheal tube placement by flexible bronchoscopy 3 minute after intubation

Secondary Outcome Measures

Name	Time	Method
pulse oximetry	5, 10, 20 min after anesthetic induction	pulse oximetry before attempt of endotracheal intubation (5 min), during determining the depth of endotracheal tube placement (10 min), after determining the depth of endotracheal tube placement (20 min)
heart rate	5, 10, 20 min after anesthetic induction	heart rate before attempt of endotracheal intubation (5 min), during determining the depth of endotracheal tube placement (10 min), after determining the depth of endotracheal tube placement (20 min)
time to verification of appropriate insertion depth of endotracheal tube placement	30 minutes after the end of surgery	time to verification of appropriate insertion depth of endotracheal tube placement by a independent observer
incidence of repositioning of endotracheal tube placement	10 min after anesthetic induction	incidence of repositioning of endotracheal tube placement (when it is found that the depth of endotracheal tube placement was inadequate determined by saturation fall or airway pressure monitoring)
blood pressure	5, 10, 20 min after anesthetic induction	systolic, diastolic, mean blood pressure before attempt of endotracheal intubation (5 min), during determining the depth of endotracheal tube placement (10 min), after determining the depth of endotracheal tube placement (20 min)