High frequency oscillatory ventilation (HFOV), is there still a room for it?
Author(s):
Elriedy M., Poxon I.
Institute(s):
Queen's Hospital BHR NHS Trust, Dept of Anaesthesiology & Intensive Care, Burton on Trent, United Kingdom
Text:
Background: Since the publishing of the OSCAR and OSCILLATE trials the use of HFOV has declined rapidly, especially with these trials suggesting no decrease and even increased mortality. We think that there's still a room for it, as we present a case of refractory hypoxaemia due to pulmonary haemorrhage managed successfully using HFOV in a general district hospital.
Case report: A 59 year old female admitted with a history of general fatigue, malaise and non-specific abdominal pain. She was noted to be pale, breathless, pyrexial and had moderate tachycardia (93 beats/minute). A recent abdominal ultrasound scan had revealed an intrauterine mass (presumed to be a fibroid). Initial blood tests revealed severe anaemia and moderately elevated total white cell count. She received 4 units transfusion of red cells and had a contrast-enhanced CT scan of chest, abdomen and pelvis. At that point she developed a shunt and required oxygen at low inspired concentrations (via nasal cannula) to maintain normal oxygen saturations. By day 4, her shunt worsened and respiratory distress became evident (40 breaths/minute) associated with haemoptysis of frank blood. She was hypoxic achieving 83% saturation with O2 flow 15L/min via non-rebreather mask. After intensive care admission and due to progressive hypoxia, patient was sedated and mechanically ventilated using BIPAP/ASB mode. Despite frequent recruitment manoeuvres and moderate PEEP settings, the maximum achieved pO2 (on FiO2 of 1.0) was 13 kPa and she continued to desaturate precipitously between these rescue attempts. It was decided to attempt HFOV. Despite the persistence of the shunt, the HFOV allowed the stabilisation of the O2 requirement and return to conventional ventilation around 96 hours post-intubation. Diagnosis confirmed as Wegener's granulomatosis with pulmonary haemorrhage, patient made full recovery. 
Discussion: Pulmonary haemorrhage is a common complication of autoimmune vasculitis. Evidence shows HFOV benefit in pulmonary haemorrhage in children, interestingly with little evidence in adults. We believe that the HFOV physical tamponading effect can be lifesaving in such cases. 
Conclusion: HFOV remains an important rescue strategy in refractory hypoxaemia. Despite not showing benefit in ARDS patients, it still can do in other subgroups with different pathology and this creates the need to identify these subgroups.