Verification of Appropriate Insertion Depth of Endotracheal Tube Placement

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.

• determination by auscultation (Other), also known as auscultation: determination of depth of endotracheal tube placement by auscultation
• determination by ultrasound (Other), also known as H-Universal Stand (sonosite, Bothell, WA, USA): determination of depth of endotracheal tube placement by ultrasound

Primary outcomes

• 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 outcomes

• 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)
• 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
• 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)
• 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)
• 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)

Sex: All, ages: 1 Month to 10 Years

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:

* Patients with pneumothorax, pleural effusion, atelectasis, pneumonia
* hemodynamic unstable patients (inotropics use)
* History of difficult intubation
* Combined upper airway anomaly

• Sangmin M. Lee, MD, PhD, Principal investigator, Samsung Medical Center
• Won Ho Kim, MD, Principal investigator, Samsung Medical Center