Bronchial Injury During Lung Isolation in a Pediatric Patient

SECTION EDITOR: WILLIAM J. GREELEY. Indications for single-lung ventilation in the pediatric patient include lung isolation and enhanced surgical exposure. The choice of technique is limited because double-lumen endobronchial tubes, standard in adults, are useful only for larger children. Alternatives for infants and young children include selective endobronchial intubation and insertion of a bronchial blocker. There are disadvantages to each approach. We describe a case in which the use of a blocker was associated with bronchial rupture. Case Report A 4-yr-old, 20-kg boy with small-cell sarcoma of the thigh presented for right thoracotomy and wedge resection of pulmonary metastases. Initial treatment had consisted of local resection followed by chemotherapy with cisplatin, ifosamide, dactinomycin, cyclophosphamide, and etoposide. Corticosteroids were included as antiemetic therapy. The patient had undergone three previous thoracotomies (one left, two right) for wedge resection of multiple pulmonary metastases. The patient had undergone no chemotherapy or surgery for 1 yr before the present operation. His functional and nutritional status were adequate, and there were no symptoms of pulmonary disease at any time. Induction of anesthesia was accomplished using IV fentanyl, midazolam, and vecuronium. During laryngoscopy, a 5-F Fogarty arterial embolectomy catheter with the balloon tip flexed to 30[degree sign] was inserted into the larynx under direct vision. After the balloon passed the vocal cords, it was rotated 90[degree sign] to the right and advanced blindly into the right mainstem bronchus. This was followed by endotracheal intubation with an uncuffed 5.0-mm tube. Anesthesia was maintained with isoflurane and nitrous oxide. Nitrous oxide was discontinued, and the blocker was inadvertently inflated with 4 mL of air in the right mainstem bronchus under direct fiberoptic visualization, completely occluding the bronchus. After moving the patient to the lateral decubitus position, the blocker location was confirmed with fiberoptic bronchoscopy. Repositioning of the blocker was not necessary at any time. Forty minutes into the thoracotomy, the surgeon observed that the blocker had perforated the membranous portion of the right mainstem bronchus. The 2-cm linear tear was closed primarily with interrupted 4-0 polyglycolic acid sutures and covered with mediastinal pleura. The lung was inflated to 40 cm H2 O pressure with saline in the field to ensure absence of an air leak. The patient's oxygenation and vital signs remained stable. The chest tube was removed on the third postoperative day, and there was no evidence of postoperative air leak or bronchopleural fistula. The patient's recovery was uneventful, without evidence of airway abnormality. Discussion Single-lung anesthesia in small children is uncommon and most often uses selective endobronchial intubation. A few reports of bronchial blockade have appeared since the technique was first described by Vale [1]. In a 14-mo-old patient, Vale [1] used a 3-F embolectomy catheter, positioned using rigid bronchoscopy and inflated with 0.5 mL of isotonic sodium chloride solution. Cay et al. [2] inserted 5-F catheters in seven children, aged 17 mo to 12 yr, positioned with fluoroscopy and inflated with 0.5 mL of radiologic contrast in saline. Other reports have described the use of 4-F and 5-F catheters inflated with air in patients as young as 2 mo [3,4]. In all these reports, no airway injuries were reported. Complications related to airway instrumentation are infrequent but potentially serious. Tracheobronchial disruption results in dissection of tissue planes, which may lead to subcutaneous emphysema, pneumomediastinum, pneumothorax, pneumopericardium, or pneumoperitoneum. Most tears occur posteriorly in the membranous portion, as in our patient, because this area is unsupported by cartilaginous bands. Bronchoscopy may be required for diagnosis. In our patient, and in other reported cases of tracheobronchial injury, prompt detection contributed to satisfactory outcome. Although surgical repair is effective, it is not necessary in some injuries [5]. The 5-F embolectomy catheter used as a blocker in our patient has a filling capacity of 3 mL recommended by the manufacturer. Although insertion seemed to be atraumatic, overdistension of the cuff may have exerted undue pressure on the bronchial mucosa. Although we would like to elicit other risk factors that may have altered the integrity of the tracheobronchial tree, they seem improbable. Three previous thoracotomies consisted of wedge resections that did not involve the right mainstem bronchus. Factors affecting tissue integrity, such as malnutrition or respiratory disease, were not a part of this patient's history. Bronchial blockade can be accomplished in adults with an 8-F Fogarty occlusion catheter with a balloon capacity of 20 mL [6]. The relatively low pressure of a partially inflated balloon may increase safety [7]. The resting volume (or diameter) is the volume of the cuff when inflated just to its natural shape; on further inflation, it becomes a high-pressure cuff. A cuff that seals the bronchus at less than its resting volume reduces the chance of mucosal injury due to vascular occlusion and ischemia. Hannallah and Benumof [8] described a method to determine the occlusion diameter of a bronchial cuff with the Univent tube. The lumen of the Univent blocker is used to apply negative pressure to detect the smallest volume, which creates a bronchial seal. In children, this technique cannot be used with an uncuffed endotracheal tube that does not create a tracheal seal. Univent tubes are too large to use in infants and small children. Hammer et al. [9] describes the use of two types of end-hole, balloon-tipped catheters to provide single-lung ventilation in children. The Foley catheter offers the advantage of a high-volume, low-pressure balloon, but the balloon size and the outer diameter of the tubing may be too large for smaller children. Using a 6-F low-volume, high-pressure balloon-tipped catheter in one patient, Hammer et al [9] determined the cuff pressure that occluded the bronchus to be 13 cm H2 O, which is within the range encountered with double-lumen endobronchial tubes in adults. Although the relationship between cuff dimensions and a patient's bronchial anatomy may affect the relative safety of a blocker, limitation of cuff pressure may be the most important factor in protecting the bronchial mucosa. This case report describes a tracheobronchial injury by a bronchial blocker in a child. Currently, the only alternative to bronchial blockade for single-lung ventilation in small children is selective endobronchial intubation, which has several disadvantages [10]. When choosing bronchial blockade, several precautions may help to prevent injury. The largest balloon whose catheter will fit beside the endotracheal tube at the cricoid level should be selected. The balloon should be inflated to the smallest volume that seals the bronchus using bronchoscopy to visualize the balloon's location and inflation diameter. Finally, measurement of inflation pressure should be explored as a method to help to prevent bronchial injury.