Even though the distinct mechanisms of helium-induced organ protection have not been completely unraveled, several signaling pathways have been identified [1]. It has been shown that heliox could decrease neutrophil infiltration, intra-alveolar edema, perivacular hemorrhage and hyaline membrane formation of acute respiratory distress syndrome in rats [2]. Nawab, et al. [3] reported that heliox attenuated lung inflammation and structural alterations of piglets in acute lung injury. In our study, serum IL-6 at baseline was found be positively and significantly correlated with the length of ventilation (LoV) [4], which supported the speculation that helium might have anti-inflammatory effect in humans in vivo. Thus, we speculated that there might be other mechanisms of action of heliox, besides its physical effects in respiratory diseases.

Heliox has been demonstrated to decrease the threshold for surfactant and ventilation by reducing the increasing oxygen requirement in Colnaghi’s study [5], which has important practical application. It is very important that the utility of heliox in reducing chronic lung disease should be expanded in more immature infants. However, one purpose of our study was to assess the effectiveness of heliox on lung inflammation cytokines. We tried to explain the reason why heliox could improve the outcome of RDS from another perspective.

Infants born before 32 weeks contribute to high occurrence of complications of prematurity such as retinopathy of prematurity, intraventricular hemorrhage and periventricular leukomalacia. Nevertheless, premature infants born between 32-36 weeks form a large proportion in NICU, and some need assisted ventilation. Longtime ventilation will increase the risk of lung injury. Length of ventilation should be the primary outcome as it plays an important role leading to ventilator- associated lung injury. Further researchon the mechanisms of heliox in respiratory diseases are still needed.

1. Gezina TML, Oei BS, Weber NC, Hollmann MW Preckel B, Cellular effects of Helium in different organs. 2010;112:1503-10.

2. Yilmaz S, Daglioglu K, Yildizdas D, Bayram I, Gumurdulu D, Polat S. The effectiveness of heliox in acute respiratory distress syndrome. Ann Thorac Med. 2013;8:46-52.

3. Nawab US, Touch SM, Irwin-Sherman T, Blackson TJ, Greenspan JS, Zhu G, et al. Heliox attenuates lung inflammation and structural alterations in acute lung injury. Pediatr Pulmonol. 2005;40:524-32.

4. Li X, Shen J, Zhao J, Tang S, Shi Y. Nasal intermittent positive pressure ventilation with heliox in premature infants with respiratory distress syndrome: A randomized controlled trial. Indian Pediatr. 2014;51:900-2.