Surfactant rescue or liquid ventilation for adult respiratory distress syndrome

Abstract

We read with great interest the article by Schulz et al1Schulz S Wiebalck A Frankenberg C et al.Low-dose surfactant instillation during extracorporeal membrane oxygenation therapy in a patient with adult respiratory distress syndrome and secondary atelectasis after chest contusion.J Cardiothorac Vasc Anesth. 2000; 14: 59-62Abstract Full Text PDF PubMed Scopus (2) Google Scholar on “Low-Dose Surfactant Instillation During Extracorporeal Membrane Oxygenation (ECMO) in a Patient with Adult Respiratory Distress Syndrome (ARDS) and Secondary Atelectasis After Chest Contusion.” The premise of the case report was that cost constraints limit concurrent surfactant therapy with ECMO for ARDS; the authors used an “extremely low dose of surfactant” and were able to achieve persistent improvement in oxygenation as demonstrated by their PO2/FIO2 ratio. Surfactant was instilled directly into atelectatic segments, and subsequent radiographs showed “increased transparency” of involved lung segments “signaling ventilation of previously collapsed lung areas.” It is conceivable that lung function improved independently of surfactant instillation during ECMO because ECMO has been shown to reverse the lung injury in neonates and infants with hypoplastic lungs that have associated surfactant deficiency.2Karamanoukian HL Glick PL Zayek M et al.Inhaled nitric oxide in congenital hypoplasia of the lung due to diaphragmatic hernia or oligohydramnios.Pediatrics. 1994; 94: 715-718PubMed Google Scholar, 3Wilcox DT Glick PL Karamanoukian HL et al.Partial liquid ventilation and nitric oxide in congenital diaphragmatic hernia.J Pediatr Surg. 1997; 32: 1211-1215Abstract Full Text PDF PubMed Scopus (39) Google Scholar Surfactant-associated proteins (SP-A and SP-B) are inactivated by the proteinaceous debris found in the alveoli in ARDS. Specifically, the lung albumin leak present in the setting of acute lung injury, as in ARDS, inactivates the surfactant-associated proteins and makes surfactant rescue therapy ineffective.4Holm BA Wang Z Notter RK Multiple mechanisms of lung surfactant inhibition.Pediatr Res. 1999; 46: 85-93Crossref PubMed Scopus (111) Google Scholar The data in the literature would support that high-dose surfactant rescue therapy is ineffective in ameliorating the acutely injured lung in ARDS; likewise, it can be argued that low-dose surfactant instillation did not contribute to the improvement in oxygenation and ventilation in this patient. More likely, this improvement resulted from decreased barotrauma while on ECMO. Partial liquid ventilation and total liquid ventilation have been shown to be effective in the therapy of ARDS in a multicenter phase I-II trial as demonstrated by Hirschl et al.5Hirschl RB Conrad S Kaiser R et al.Partial liquid ventilation in adult patients with ARDS: A multicenter phase I-II trial.Ann Surg. 1998; 228: 692-700Crossref PubMed Scopus (109) Google Scholar Perfluorocarbons are less expensive than the $300,000/patient that Schulz et al1Schulz S Wiebalck A Frankenberg C et al.Low-dose surfactant instillation during extracorporeal membrane oxygenation therapy in a patient with adult respiratory distress syndrome and secondary atelectasis after chest contusion.J Cardiothorac Vasc Anesth. 2000; 14: 59-62Abstract Full Text PDF PubMed Scopus (2) Google Scholar estimate for the treatment of an adult with ARDS. In addition, several studies have indicated that perfluorocarbons are not inactivated by the albumin leak in the alveoli, and partial liquid ventilation may decrease the albumin leak in the setting of acute lung injury.6Colton DM Till GO Johnson KJ et al.Partial liquid ventilation decreases albumin leak in the setting of acute lung injury.J Crit Care. 1998; 13: 136-139Abstract Full Text PDF PubMed Scopus (21) Google Scholar Neutrophil accumulation has been shown to be reduced during partial liquid ventilation.7Rossman JE Caty MG Rich GA et al.Neutrophil activation and chemotaxis after in vitro treatment with perfluorocarbon.J Pediatr Surg. 1996; 31: 1147-1150Abstract Full Text PDF PubMed Scopus (59) Google Scholar, 8Colton DM Till GO Johnson KJ et al.Neutrophil accumulation is reduced during partial liquid ventilation.Crit Card Med. 1998; 26: 1716-1724Crossref PubMed Scopus (70) Google Scholar In contrast to surfactant, which is inactivated by proteinaceous products, perfluorocarbon can ameliorate the deleterious manifestations of lung injury in ARDS. We commend the authors for their heroic use of surfactant therapy; we look forward to a prospective trial using low-dose surfactant therapy in ARDS.