To the Editor:—
Recent developments of thoracoscopic surgical instruments and techniques have increased the demand for selective lung ventilation in younger children. Because the use of pediatric double-lumen endotracheal tubes 1is limited, this is conventionally accomplished by blocking the required bronchus with a Fogarty embolectomy catheter 2or with a pulmonary artery catheter. 3In most reported cases, a bronchial blocker is placed blindly or through a rigid bronchoscope before tracheal intubation. Appropriate positioning of the blocker is subsequently confirmed by fiberoptic bronchoscopy, auscultation, or chest radiography. However, these methods entail two major disadvantages. First, hypoxemia can occur during the placement of a blocker. Second, when dislocation of the blocker occurs during surgery, repositioning is difficult.
To overcome these problems, we fabricated a double-access-port endotracheal tube by combining two conventional Murphy-type tubes for the use of one-lung ventilation in pediatric patients.
For the equipment preparation (fig. 1)
, a tracheal tube of the appropriate inner diameter (ID) (uncuffed or cuffed) is selected (inner tube). Another tube of ID within 0.5 mm larger than the outer diameter (OD) of the inner tube is prepared (outer tube). A side port is made at a position approximately 8 cm from the proximal end of the inner tube. The distal three fifths of the outer tube is cut off, and a side port slightly larger than the OD of the inner tube is also made at 2 or 3 cm proximal from the distal cut end. These side holes can be cut simply with scissors in the folded tubes and with an appropriate surgical instrument, such as an aorta punch. The inner tube then protrudes from the side port through the distal cut end of the outer tube, such that the side port of the inner tube is placed within the outer tube lumen. To facilitate insertion, water lubrication is helpful. For a cuffed inner tube, an inverse insertion is recommended to avoid possible cuff damage. A tight air seal can be easily achieved by taping if an air leak is found at the bifurcation of the tubes. The taping can also prevent slippage of the tubes that could result in an airway obstruction. The 15-mm connector of the outer tube is sealed with a silted rubber cap so that it can be used as an access port for a blocking catheter. To ensure airtightness during the blocker operation, we insert a shortened catheter sheath into this rubber cap.
This tube provides independent access for blocker operations and ventilation both. Thus, sufficient ventilation can be obtained during the blocker positioning. This could decrease the risk of hypoxemia and make intraoperative repositioning of the balloon practicable.
Currently, we have treated seven patients, aged 18 months–5 yr, who underwent thoracoscopic surgery with the use of this device. In the youngest patient, a 5.0-mm ID inner tube with a 7.0-mm ID outer tube was used. A Fogarty catheter (4-French) was positioned in the appropriate bronchus of each child during fiberscopic vision (Olympus LF-P, 2.2-mm OD, or LF-DP, 3.1-mm OD, passed through the inner tube; Olympus Optical Co., Ltd., Tokyo, Japan). Sufficient ventilation through the inner tube was obtained during the blocker positioning using a rubber-sealed Y connector (Bodai Swivel Y; Sotek Medical Inc., Hingham). Inflation of the balloon established adequate selective lung ventilation as well as excellent surgical access in all cases.