| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
| ||||||||||||||
| ||||||||||||||
|
|
|
|
||||||||||||
|
||||||||||||||
Stanford University Medical Center, Stanford, CA
To The Editor:
Takahashi et al. (1) describe selective bronchial blockade in a 2.5-kg infant using a 4F Fogarty catheter guided by a fiberoptic bronchoscope (FOB). The outer diameter of the FOB was 2.2 mm. The catheter and FOB were placed via a 4.5-mm inner diameter (ID) endotracheal tube.
There are several concerns regarding the use of this technique in very small infants. First, a 4.5-mm ID endotracheal tube is too large for most infants <1 yr of age and is certainly too large for most neonates. The authors do not mention auscultation of a gas leak around the endotracheal tube, a standard maneuver to determine whether the endotracheal tube is too large (e.g., no leak occurs at an inflating pressure of up to 30–35 cm H2O). Ischemia of the tracheal mucosa leading to subglottic stenosis may occur as a consequence of placing and leaving in place a tight-fitting endotracheal tube.
According to the technique the authors describe (1), the Fogarty catheter and FOB must be passed through an indwelling endotracheal tube. A 4F Fogarty catheter has a maximum outer diameter (at the balloon) of approximately 1.3 mm. When used in combination with a FOB with an outer diameter of 2.2 mm, the combined diameter is 3.5 mm. Even well lubricated, the two devices will not pass through an endotracheal tube smaller than 4.0 mm ID and will pass easily only through an endotracheal tube 
4.5 mm ID. This technique, therefore, has limited application in neonates, for whom a 3.0-mm ID or 3.5-mm ID endotracheal tube is appropriate. A more suitable method for bronchial blockade might be placing the catheter outside the endotracheal tube (2). The advantages of so doing include the ability to use a smaller endotracheal tube, e.g., 2.5–3.0 mm ID. The combined diameter of the body of the catheter (approximately 1 mm) and the endotracheal tube may be as small as 3.5 mm. The catheter balloon position can be confirmed by passing a small FOB through the endotracheal tube or by fluoroscopy.
To avoid airway injury, anesthesiologists must be mindful of the diameters of both the airways and devices placed therein. Appropriate maneuvers must be performed to ensure that tight-fitting endotracheal tubes are not placed to facilitate single-lung ventilation in infants and children.
References
Department of Anesthesiology and Emergency Medicine, Tohoku University Postgraduate Medical School, Sendai, Japan
In Response:
We are grateful for Dr. Hammer’s comments on our recent publication (1). Dr. Hammer raised an important issue concerning damage resulting from oversized endotracheal tubes, and we certainly agree that a 4.5-mm ID endotracheal tube is too large for most small infants. As described in our report, the 4.5-mm tube was not selected to facilitate the use of our technique but so that our selective lobar blocking technique (2) could be employed in such a small infant because a 4.5-mm tube was already in place. Prolonged mechanical ventilation had apparently enlarged the patient’s trachea, as the initially placed 3.5-mm tube had been replaced twice, first with a 4.0-mm tube and then with a 4.5-mm tube because of the developed air leak before the thoracoscopic surgery. Although it was not mentioned, auscultation was performed and leakage around the 4.5-mm tube was confirmed acoustically at an inflating pressure of 15–20 cm H2O in the operating room.
However, the method described by Dr. Hammer (3) could enable the application of selective lobar-bronchial blocking in a much larger number of infants (including neonates), not only those with exceptionally large tracheae as in our report. Nonetheless, the purpose of our case report was not to recommend the use of our technique in small infants for whom the minimal applicable tube is still too large, but to illustrate advantages of the reduced exposure of the intrathoracic space in children with poor general condition. Recent sophisticated techniques in thoracoscopic surgery do not always require the total deflation of the one lung.
References
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
