Acute intraoperative endotracheal tube obstruction associated with a heat and moisture exchanger in an infant.

Abstract

To the Editor: We report a small infant who developed acute airway obstruction under general anesthesia after a heat and moisture exchanger (HME) was added to the anesthesia circuit to preserve heat and humidity. The use of this device is not free of complications. This 6-wk-old, 3-kg former premature male infant was scheduled for herniorrhaphy and orchiopexy. After an uneventful induction, the trachea was intubated, and 2.0 mL of 0.25% bupivacaine was injected into the caudal space. General anesthesia was maintained with oxygen, nitrous oxide, isoflurane, and pancuronium. The patient's lungs were mechanically ventilated, and breath sounds were equal bilaterally. Peak inspiratory pressure was 24 cm H2 O. A neonatal and infant HME (Gibeck, Upplands Vasby, Sweden) was placed between the 3.0 endotracheal tube (ETT) and the breathing circuit of the circle system. Within the next minute, the SpO2 decreased rapidly from 100% to 60%. Manual ventilation was initiated, and the SpO2 increased to 100% in less than 60 s. Breath sounds were equal bilaterally, the ETT was suctioned, and no secretions were noted. CO2 was detected by capnography. On inspection, a 2 x 3 mm piece of paper was noted to be swirling between the 15-mm connector of the ETT and the HME. The HME was removed and inspected, and it appeared intact (Figure 1). The patient's lungs were mechanically ventilated, and the peak inspiratory pressure returned to baseline. The use of the HME was abandoned. No further episode of peripheral oxygen desaturation was noted. The surgical procedure was completed, and the patient was extubated without complications.Figure 1: The small piece of paper (arrow) that caused airway obstruction is shown. The heat and moisture exchanger (a) is disconnected from the endotracheal tube (b).Defects in the HME (i.e., dislodgement of its components) have been associated with the inability to adequately ventilate the lungs [1-3]. The use of the HME in patients with active bleeding from the ETT or with an active, heated, humidified circuit has been associated with airway obstruction and should be avoided [3-5]. When using a HME in the breathing circuit, the HME should be placed in the circuit and the circuit tested and inspected before beginning anesthesia. Alfonso Casta, MD Constance S. Houck, MD Department of Anesthesia; Children's Hospital; Boston, MA 02115