Anesth Analg 2007;104:218-219
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000250217.13524.f2
LETTER TO THE EDITOR
Editor-in-Chief Steven L. Shafer
Ventilation Management During Neonatal Thoracic Surgery
Dietmar Enk, MD, PhD,
Georg Rellensmann, MD,
Thomas Brussel, MD, PhD, FANZCA,
Hugo Van Aken, MD, PhD, FRCA, FANZCA,
Michael Semik, MD, PhD, and
Christoph Schmidt, MD
Department of Anesthesiology, University Hospital Maastricht, Maastricht, The Netherlands, d.enk{at}t-online.de (Enk)
Department of Pediatrics, University of Münster Hospital, Münster, Germany (Rellensmann)
Department of Anesthesiology and Pain Management, The Canberra Hospital, Australian National University, Canberra, Australia (Brussel)
Department of Anesthesiology and Surgical Intensive Care Medicine (Van Aken)
Department of Chest, Heart, and Vascular Surgery (Semik)
Department of Anesthesiology and Surgical Intensive Care Medicine, University of Münster Hospital, Münster, Germany (Schmidt)
In Response:
Drs. Bouchut and Claris (1) emphasize the beneficial effects of high-frequency oscillatory ventilation (HFOV) in cases of neonatal and pediatric acute lung injury. We fully agree that special infant ventilators and HFOV are an indispensable strategy in caring for preterm, newborn infants. However, although generally effective in maintaining and improving gas exchange in small infants, HFOV might not be the best approach in every setting.
The major concern in infants with congenital emphysema is to protect the emphysematous regions from further over-expansion caused by positive airway pressure. In our patient, HFOV used during periods of recurrent pulmonary infection induced mediastinal shift with severe hemodynamic compromise. This required surgical removal of the left upper lobe (2). Because HFOV was responsible for this complication, we intervened by placing a pediatric endobronchial blocker in the left mainstem bronchus to establish single-lung ventilation, thus precluding further expansion of the emphysematous lobe.
We would like to address some other concerns raised by Drs. Bouchut and Claris. First, the 4.0-mm ID endotracheal tube did not cause laryngotracheal trauma. In the neonatal intensive care unit, an air leak was observed with a 3.5-mm tube during periods of HFOV (2). Second, we did not adapt a technique for adults to our neonatal patients. The endobronchial blocking device used was designed and clinically validated for lung isolation in small infants. However, placement of the device generally requires an endotracheal tube with an inner diameter of at least 4.5 mm. The purpose of our report was to describe how we applied three distinct modifications of the recommended approach to permit use of an endobronchial blocker through a 4.0-mm endotracheal tube, permitting its use in newborns. Finally, we did not expose the neonate to lung injury by high peak airway pressures and sheer stress forces. During single-lung ventilation, we limited peak airway pressure to 25 cm H2O. While placing the endobronchial blocker, ventilation was continued through a "virtual" 3.0-mm endotracheal tube, obtained by subtracting the cross-sectional area of the blocker shaft (2.27 mm2) and the fiberoptic bronchoscope (3.14 mm2) from the cross-sectional area of a 4.0-mm endotracheal tube (12.57 mm2). The result, 7.16 mm2, is slightly larger than the area of a 3.0-mm endotracheal tube (7.07 mm2). After the fiberoptic bronchoscope was removed, the remaining cross section increased to 10.3 mm2, which exceeds the cross-sectional lumen of a 3.5-mm endotracheal tube (9.62 mm2). Despite a minute ventilation of 1.4–1.7 L at a respiratory rate between 30–40/min, carbon dioxide increased, reflecting the additional dead space added by the multiport adapter.
Our surgeons consider conditions for open lung surgery satisfactory during intraoperative HFOV. However, confronted with the special challenges of our small patient, our surgeon determined that lung isolation was required before removing the over-expanded lobe.
In summary, we have shown how to isolate a lung in small infants who require single-lung ventilation in the intensive care unit or operating room.
REFERENCES
- Bouchut J-C, Claris V. Ventilation management during neonatal thoracic surgery. Anesth Analg 2007;104:218.[Free Full Text]
- Schmidt C, Rellensmann G, Van Aken H, et al. Single-lung ventilation for pulmonary lobe resection in a newborn. Anesth Analg 2005;101:362–4.[Abstract/Free Full Text]
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