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Departments of *Anesthesiology and Surgical Intensive-Care Medicine, Pediatrics, and Chest, Heart, and Vascular Surgery, University of Münster Hospital, Münster, Germany; Department of Anaesthesiology and Pain Management, The Canberra Hospital, Australian National University, Canberra, Australia; and ||Department of Anesthesiology and Intensive-Care Medicine, St.-Antonius-Hospital, Kleve, Germany
Address correspondence and reprint requests to Christoph Schmidt, MD, Klinik und Poliklinik für Anästhesiologie und operative Intensivmedizin, Universitätsklinikum Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany. Address e-mail to schmch{at}uni-muenster.de.
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Introduction |
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Case Report |
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General anesthesia with thiopental, sufentanil, rocuronium, and sevoflurane was administered. The infant was monitored with capnography, a temperature probe, pulse oximetry, and electrocardiography. Invasive arterial blood pressure was measured in the left radial artery. A 22-gauge central venous catheter was placed via the right internal jugular vein. The infant was intubated nasally with an uncuffed 4.0-mm ID ET (Smiths Medical Deutschland GmbH, Kirchseeon, Deutschland). FWEB (Cook Deutschland GmbH, Mönchengladbach, Germany) was coaxially guided into the left main stem bronchus using a 2.0-mm pediatric fiberscope (BF-N20; Olympus Deutschland GmbH, Hamburg, Germany).
The FWEB is a 65-cm double-lumen catheter. At its tip, the FWEB has a 1-cm-long, spherical, low-pressure, large-volume balloon, inflated via a 0.3-mm lumen. The second, 0.7-mm lumen carries a guidewire exiting the FWEB in a small, 6-mm loop. The FWEB is placed coaxially through the 30° angled blocker port of a multiport adapter. The blocker port has a Tuohy-Borst valve to maintain an air-tight seal while allowing both smooth and independent movement of the FWEB, and also a secure lock of the FWEB, once in place. The multiport adapter has a second port for passage of a fiberscope and a third, 90° angled port for connection to the anesthesia breathing circuit. Routinely, the fiberscope is coupled to the FWEB loop within the multiport adapter before advancement into the trachea (8). Because the FWEB is guided by a bronchoscope, both the blocker and the fiberscope must pass through the indwelling ET. Because the tip of the FWEB with the balloon deflated has a diameter of 2.5 mm and the smallest available fiberscope has an outer diameter of 2.0 mm, the use of the FWEB is restricted to an ET having an ID of at least 4.5 mm (8,9).
Three distinctive modifications of the standard procedure permitted use of a 4.0-mm ET, which was the largest tube that could be placed in our patient. First, the shaft of the FWEB has an outer diameter of 1.7 mm as compared with the 2.5 mm of the deflated balloon. Thus, advancing the balloon into the trachea and subsequently coupling the fiberscope to the FWEB by passing the guide loop intratracheally saved 0.8 mm in diameter. Nevertheless, a prerequisite for unimpeded advancement of both the FWEB and the fiberscope is sufficient lubrication of the ET, the FWEB, and the fiberscope to minimize friction (SilkosprayTM; Willy Rüsch GmbH, Kernen, Germany). Second, the connector of the 4.0-mm ET was removed and replaced by the connector of a 6.0-mm ET, which was attached to the outer surface of the 4.0-mm ET by tape. In this way the most rigid part of the 4.0-mm ET was eliminated rendering the whole assembly more flexible. Third, the bronchoscopy port has a diaphragm with a 3.5-mm central hole—too large to provide an air-tight seal with a 2.0-mm fiberscope. To prevent leakage during positive pressure ventilation, the bronchoscopy port was covered by an adhesive membrane (OpsiteTM; Smith & Nephew GmbH, Lohfelden, Germany), which was perforated by a needle. Thus, it was possible to manually ventilate the infant throughout the positioning maneuver. To position the FWEB, the fiberscope was advanced through the membrane, multiport adapter and ET, and at last caught the guidewire loop of the FWEB intratracheally, effectively coupling the two together. The fiberscope was then advanced deep into the left mainstem bronchus, guiding the FWEB into position. The balloon was slowly inflated under direct vision until the bronchial lumen was entirely occluded. The FWEB was then secured in place by tightening the Tuohy-Borst valve. The fiberscope was removed and the bronchoscopy port closed (Fig. 1). The left lung collapsed because of absorption atelectasis and this was aided by continuously suctioning the 0.7-mm lumen of the FWEB after removal of the guidewire. Before surgery, proper positioning of the FWEB was verified fiberoptically. For surgery, the infant was placed in the right-sided decubitus position.
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During 2.5 h of SLV, the respiratory rate was 30–40/min, peak airway pressure was limited to 25 cm H2O resulting in a minute volume of 1.4–1.7 L. The arterial carbon dioxide pressure increased during mechanical ventilation to a maximum of 84 mm Hg corresponding to a pH of 7.06. Manually ventilating the lung reestablished normal values for the arterial carbon dioxide tension. Throughout the procedure, the infant was ventilated with pure oxygen with an arterial partial pressure of oxygen of approximately 350 mm Hg. Surgery was performed without any problems and the surgeon appreciated the "excellent conditions." After resection of the left upper pulmonary lobe, the left lung was cautiously expanded under visual control and the FWEB removed. After surgery, the patient was admitted back to the pediatric intensive care unit with the 4.0-mm ET still in place. On postoperative day 1, the infant was nasally extubated and after uneventful recovery discharged to the ward.
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Discussion |
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During early life, anatomical and physiological differences define the practical limits of transposing techniques of SLV for adult patients onto pediatric practice. Therefore, the ideal method for SLV in infants has yet to be established. Nevertheless, the increasing frequency of minimally invasive thoracic surgical procedures has prompted a resurgence of interest in techniques for lung isolation (10). Because of their large outer diameter, double-lumen tubes and UniventTM tubes are not appropriate for this age group. The simplest, applicable method available for SLV is the use of a single-lumen ET (11). A regular cuffed ET that is 0.5–1 mm ID smaller than indicated for endotracheal intubation can be used to allow the cuff to fit the main stem bronchus. Three-millimeter cuffed tubes have been applied in infants <12 months old. However, this technique has certain limitations: 1) the mainstem bronchi are out of reach for conventional ETs if the nasotracheal route is preferred to minimize the risk of dislocation; 2) significant airway trauma may result from advancing an ET blindly, especially if a stylet is used to enter the left mainstem bronchus; 3) hypoxemia may result from obstruction of the upper lobe bronchus by the cuff of the ET, typically when the short right mainstem bronchus is intubated; 4) suction cannot be applied to the operative side to promote lung collapse; and 5) oxygen and continuous positive airway pressure cannot be administered to the operative lung if the patient experiences oxygen desaturation.
Desaturation, however, is particularly common in infants because of their increased oxygen consumption and is exacerbated in the lateral decubitus position. In adults, ventilation and perfusion are better matched during SLV in the lateral position. In infants, however, the reverse is true, so that oxygenation is worse during SLV in the lateral decubitus versus supine position (12). The highly compliant chest wall in combination with a decline in functional residual capacity caused by anesthesia and muscle relaxation causes airway collapse during tidal breathing and accentuates intrapulmonary shunting (2). Therefore, the use of an end-hole endobronchial blocker during SLV in young children, through which oxygen and continuous positive airway pressure can be administered, is advantageous. Moreover, the multiport adapter allows maintenance of positive pressure ventilation and adequate oxygenation during initial placement and also easily permits repositioning maneuvers of the FWEB when necessary. Consequently, adequate oxygenation was provided in our setting, but during SLV arterial carbon dioxide tension increased continuously. One has to be aware that the components of the system (multiport adapter, moisture exchanger filter) significantly add to dead space ventilation, leading to the limits of acceptable respiratory acidosis in our case.
Others have used continuous caudal epidural anesthesia in congenital lobar emphysema in an attempt to avoid positive pressure ventilation (13). Induction of anesthesia and positive pressure ventilation may cause expansion of the emphysematous lobe, compression of the surrounding normal lung, and ultimately mediastinal shift as was already present in our infant before induction of anesthesia (14). Whereas this regional anesthesia technique combined with mild sedation accounts for the risk of overinflation of the affected lobe, hypoxemia may result from spontaneous breathing in the lateral decubitus position. Considering the challenges of tracheally intubating such a small, spontaneously breathing infant under topical anesthesia, maintaining adequate spontaneous ventilation in the lateral decubitus position afterward, and establishing SLV during surgery with a high risk of desaturation, we primarily opted for general anesthesia. Use of the FWEB allowed us to isolate the emphysematous lobe immediately after nasal intubation under controlled conditions. This was the crucial argument in favor of general anesthesia.
In conclusion, we have demonstrated the feasibility of SLV in a newborn using a coaxially placed fiberoptically directed endobronchial blocker.
The authors appreciate the help of Michael Klatthaar in caring for the patient.
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This article has been cited by other articles:
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  J.-C. Bouchut and O. Claris Ventilation Management During Neonatal Thoracic Surgery Anesth. Analg., January 1, 2007; 104(1): 218 - 218. [Full Text] [PDF]
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D. Enk, G. Rellensmann, T. Brussel, H. Van Aken, M. Semik, and C. Schmidt Ventilation Management During Neonatal Thoracic Surgery Anesth. Analg., January 1, 2007; 104(1): 218 - 219. [Full Text] [PDF]
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