Anesthesiology Research

Dr. Wolf’s research focus is on novel modes of ventilation in pediatric respiratory failure and noninvasive means of assessing lung volume in critically ill patients. In particular, Dr Wolf has a focus on the regional distribution of ventilation in children with acute respiratory distress syndrome (ARDS). This is particularly important since ARDS is a heterogeneous disease, and different areas in the lung are associated with atelectasis and overdistension, potentially leading to additional lung injury during mechanical ventilation. Further research focus is on ECMO, Partial Liquid Ventilation, High Frequency Oscillatory Ventilation and novel modes of respiratory support such as Neurally Adjusted Ventilatory Assist (NAVA).

Dr. Wolf’s group uses a technology called electrical impedance tomography (EIT) to measure regional lung volume changes. Dr. Wolf has contributed to this research group developing methods to guide mechanical ventilation in children with ARDS and in animal models of ARDS. He refined EIT so that it is applicable in the pediatric critical care setting. The group’s description of regional lung volume changes in children with pediatric ARDS in Critical Care Medicine was the first published application in critically ill children.

Dr. Wolf currently receives grant support from the Center of Integration of Medicine and Technology (CIMIT) and the Translational Research program (TRP) of Children’s Hospital Boston for finding ways to guide mechanical ventilation with EIT and reduce lung injury in animal models and children with ARDS.

Investigating novel modes of ventilation is important since the mortality of ARDS in children is as high as 22%. While ventilator support of ARDS is lifesaving, ventilator associated lung injury (VALI) adds significantly to the morbidity and mortality of patients with acute lung injury.

In an animal model of ARDS, Dr. Wolf has described regional ventilation-induced impedance changes that occur during High Frequency Oscillatory Ventilation (HFOV). This is particularly relevant, as those lung volume changes are very small, but during the high pressures used during HFOV regional overdistension could add significantly to morbidity of patients. In this study, the EIT-derived center of ventilation during high-frequency oscillatory ventilation correlated with oxygenating efficiency as measured by the shunt fraction. Lung recruitment during high frequency oscillatory ventilation produced a significant shift of regional ventilation toward dependent areas of the lung and led to overdistension of nondependent areas [Wolf GK, Grychtol B, Frerichs I, Zurakowski D, Arnold JH. Regional Lung Volume Changes during High Frequency Oscillatory Ventilation. Pediatr Crit Care Med. 2010; 11 (3)].

Subsequently, Dr. Wolf reported regional ventilation changes during HFOV and partial liquid ventilation using EIT. In this study, Dr Wolf described a correlation of regional lung overdistension measured with EIT with morphologic changes seen on lung histopathology. Treatment with perflubron during HFOV compared to a control group in an animal model of lung injury led to regional overdistension of dependent lung areas, as evidenced by increased alveolar overdistension on lung histopathology, decreased mean lung impedance and decreased HFOV-induced regional lung volume changes as measured by EIT. [Wolf GK, Grychtol B, Boyd T, Zurakowski D and Arnold JH. Regional overdistension identified with electrical impedance tomography in the perflubron-treated lung. Physiol Meas 2010; 31(8):85-95.]