VIDEO-ASSISTED thoracoscopic surgery (VATS) has numerous advantages compared with open thoracotomy. Single-lung ventilation (SLV), essential during VATS, usually is performed with a double-lumen endotracheal tube (ETT) in older children and adults. Because no double-lumen ETT is available for infants and small children, alternative techniques must be used to provide SLV in these patients. We describe our experience providing SLV to two young children.
A 6-yr-old, 18-kg boy was scheduled to undergo right thoracoscopy for excision of pulmonary metastases from Stage D Wilms' tumor. He had previously undergone chemotherapy, radiation therapy, and a radical right nephrectomy. Medical history was otherwise unremarkable.
After placement of routine monitors, anesthesia was induced with thiopental, fentanyl, and pancuronium and maintained with isoflurane, oxygen, and pancuronium. The patient's trachea was intubated with a 5.0 mm-ID, uncuffed ETT using direct laryngoscopy. The distance from the patient's teeth to the carina was identified by slowly advancing the ETT until diminished breath sounds were auscultated over the left thorax. The ETT was advanced further into the right mainstem bronchus. A 0.025-mm, 140-cm, J-tipped guidewire calibrated with markings at 5-cm intervals was passed through the ETT into the right mainstem bronchus. The ETT was removed, leaving the guidewire in place. An 8-Fr Foley catheter was advanced over the indwelling guidewire into the right mainstem bronchus. The Foley catheter had been modified by amputation of its tip, creating an end-hole, balloon-tipped catheter, also calibrated with markings placed 5 cm apart. The patient's trachea was intubated with a 5.0 mm-ID uncuffed ETT by direct laryngoscopy. Breath sounds were noted to be equal bilaterally with the balloon of the Foley catheter deflated. After inflating the balloon with 1.5 ml of air, breath sounds and chest excursion on the right side were markedly diminished. A 2.2 mm-OD fiberoptic bronchoscope (ENT-2, Machida, Orangeburg, NY) was passed down the ETT. Fiberoptic examination of the carina revealed the Foley catheter entering the right mainstem bronchus. As the balloon was slowly inflated, its proximal margin could be visualized just within the distal trachea, with the balloon extending down the right mainstem bronchus. The distal trachea and left mainstem bronchus remained patent. The Foley catheter was taped to the ETT to prevent inadvertent displacement during the surgery. Chest fluoroscopy was performed with the balloon deflated, demonstrating expansion of the right lung (Figure 1(A)).
The patient was positioned in the left lateral decubitus position. The catheter balloon was reinflated, and breath sounds were again absent on the right side while preserved on the left. During the thoracoscopic surgery, which included excision of lesions in the right lung apex and lower lobe, the entire right lung remained atelectatic. Sp sub O2was 98–100% during SLV. After the completion of surgery, the patient was placed supine, and fluoroscopy was repeated with the catheter balloon inflated with intravenous contrast (Hypaque), demonstrating occlusion of the right mainstem bronchus and deflation of the right lung (Figure 1(B)). After the balloon was deflated, the patient's lungs were manually ventilated with high inflating pressures to achieve complete reexpansion of the right lung. After antagonism of residual neuromuscular blockade, the ETT and Foley catheter were removed, and the patient was transported to the recovery room while receiving supplemental oxygen and with an SpO2of 99–100%.
A 5-yr-old, 21-kg girl was scheduled to undergo right thoracoscopy for excision of a right lower lobe lung nodule. She had previously undergone a left nephrectomy for Wilms' tumor and multiple courses of chemotherapy. Her medical history was otherwise unremarkable.
After placement of routine monitors, anesthesia was induced with halothane, nitrous oxide, and oxygen. Anesthesia was maintained with isoflurane, oxygen, and pancuronium. A 6-Fr end-hole, balloon-tipped catheter (Balloon Wedge Pressure Catheter, Reading, PA) was placed in the patient's right mainstem bronchus with a technique identical to that described in case 1. After the catheter placement was verified by auscultation and fiberoptic bronchoscopic examination, the catheter was taped to the ETT.
The patient was placed in the prone position. The catheter balloon was inflated with 1 ml of air, and breath sounds over the right chest were noted to be markedly diminished. The pressure in the catheter cuff was measured to be 13 cmH2O (Digital P-V Gauge, Mallinckrodt, St. Louis, MO). The procedure proceeded as planned, during which the patient's right lung remained fully deflated. During SLV, the patient's Sp sub O2decreased to 95%. After administration of a single, prolonged inspiration, continuous positive airway pressure (CPAP) to 10 cmH2O was administered by insufflating oxygen via the lumen of the indwelling catheter. With CPAP, the SpO2increased to 99% without significant distension of the right lung. After completion of the thoracoscopy, the catheter balloon was deflated, and both lungs were ventilated with 100% Oxygen2. After antagonism of residual neuromuscular blockade, the ETT and balloon catheter were removed, and the patient was transported to the recovery room breathing blow-by oxygen with an SpO2of 100%.
VATS has been associated with diminished perioperative morbidity compared with thoracotomy. Advantages of VATS include reduction in postoperative pain and impairment of lung function, more rapid postoperative recovery with earlier hospital discharge, and smaller incisional scars. Initially described in adult patients, VATS has been performed more recently in children as small as 3 kg. .
Anesthetic management for patients undergoing VATS includes SLV. In adults and older children, the use of a double-lumen ETT is standard practice for providing SLV. The smallest double-lumen ETT available is 26 Fr (Rusch, Duluth, GA). With an outer diameter of 8.7 mm, comparable to a 6.5 mm-ID ETT, this tube generally cannot be used in children younger than 7–8 yr.
Two methods of SLV for children younger than 7 yr undergoing chest surgery have been described. [4,5]Both rely on bronchial blockade, that is, obstruction of a nonventilated bronchus leading to selective lung collapse from "absorption atelectasis." The two methods are (1) selective mainstem bronchial intubation of the nonoperative side with a conventional ETT and (2) bronchial blockade with a Fogarty catheter balloon. [4,5]Suctioning or administration of CPAP to the nonventilated lung cannot be performed with either of these techniques.
Arterial hypoxemia occurs during SLV due to continued shunting of blood through the nonventilated lung and ventilation-perfusion abnormalities in the ventilated lung. These changes are associated with body position, neuromuscular blockade and mechanical ventilation, reduction in hypoxic pulmonary vasoconstriction, and alterations in functional residual capacity under anesthesia. Application of positive end-expiratory pressure to the dependent lung increases functional residual capacity but does not consistently increase PaO2. [6,7]The most effective maneuver to increase PaO2during SLV is the application of CPAP to the nondependent, nonventilated lung. [7,8]Alveolar patency and oxygen uptake in the nondependent lung may be maintained with CPAP 5–10 cmH2O. This level of CPAP generally is not associated with overdistention of the operated lung or adverse hemodynamic consequences, as may occur with higher levels of CPAP. CPAP can be applied to the nondependent lung with a variety of delivery systems. We used an end-hole, balloon-tipped catheter. Inflation of the balloon provided bronchial blockade, while the patent lumen allowed administration of CPAP when needed. CPAP was delivered via a modified Mapleson D circuit similar to that described by Arandia with substitution of a calibrated exhalation relief valve.
A Foley catheter was used in our first patient. This catheter is constructed of silastic and contains a low-pressure, high-volume balloon, which minimizes the risk of mucosal injury. Because the right mainstem bronchus is short, the relatively protracted length of this balloon may increase the likelihood of undesired occlusion of the right upper lobe bronchus. For this reason, we elected to position the catheter with its cuff partially within the tracheal lumen. Another disadvantage of the Foley catheter is its relatively thick wall, which occupies a greater percentage of the tracheobronchial lumen. Therefore, we chose a balloon wedge pressure catheter for our second patient. This catheter is radiopaque, has a thin wall, and is precalibrated in 10-cm increments. The inflation lumen has a one-way, Luer-fitted stopcock at its proximal end, so accidental deflation is unlikely. The catheter is tapered at its distal end under the latex balloon so that the deflated balloon does not increase the external diameter of the catheter. We were concerned that inflation of the low-volume, high-pressure balloon might exert excessive pressure against the bronchial mucosa. Measurement of the balloon pressure at a volume sufficient to seal the airway was 13 cmH2O, a level we considered acceptable. .
In both of our patients, catheters were placed in the right mainstem bronchus. We also have placed a left-sided bronchial catheter after selective intubation of the left mainstem bronchus. This may be facilitated by turning the patient's head to the right and positioning the ETT with its bevel facing rightward during intubation. Alternatively, a catheter can be placed in the left mainstem bronchus under fiberoptic bronchoscopic guidance.
The use of an end-hole, balloon-tipped catheter allows selective bronchial blockade with the ability to provide CPAP or suction to the nonventilated lung. We believe the balloon wedge catheter provides an alternative to previously described techniques for SLV in pediatric patients.