High-frequency oscillatory ventilation in H1N1 patients with acute respiratory distress syndrome
杨向红1 Dana Savicid2
1. Zhejiang provincial peoples hospital, 2. UPstate medical university hospital
Background: The 2009 novel swine-origin influenza A (H1N1) virus led to a worldwide pandemic. A number of H1N1 patients rapidly developed severe progressive respiratory failure and required mechanical ventilation. Hypoxemia and the development of acute respiratory distress syndrome (ARDS) were identified as an independent risk factor for mortality. Numerous studies have suggested that high-frequency oscillatory ventilation (HFOV) used as rescue therapy may improve oxygenation in ARDS patients.
Purpose: To evaluate the efficacy and safety of HFOV on 4 patients with ARDS attributable to H1N1 infection who had failed conventional lung protective ventilation due to refractory hypoxia or respiratory acidosis.
Methods:A total of 4 H1N1 patients with ARDS who failed to respond to conventional ventilation (CV) were analyzed retrospectively during HFOV. Mean airway pressure was initially set 5 cmH2O higher than that for conventional ventilation and was subsequently adjusted to maintain oxygen saturation >90% and FiO2 <0.6. Patient characteristics , oxygenation, ventilation, and hemodynamic parameters before initiating HFOV and during HFOV support for a total of 72 hours wereextracted from the records.
Results: 4 H1N1 patients with ARDS who were on HFOV were females and all of them were morbidity obesity. On the day of admission to ICU, the median of APACHE II score is 20(range, 17-22). 3 patients were survived. 1 patient died of septic shock and MODS. There was a considerable increase in PaO2/FiO2 ratio and a significant decrease in oxygenation index after 1-8hours of HFOV, and this increase and decrease was maintained after 48 hours of HFOV. In patient#1 and #2 there were no significant changes in PH and PaCO2 throughout the duration of HFOV. Patient#3 had episode of severe hypercapnia that her PaCO2 reached 102mmHg prior to the initiation of HFOV, however within 1 hour of initiation of HFOV her PaCO2 started to decrease and went to normal at 24 hours after initiation of HFOV. Patient#4 had a episode of hypercapnia and a severe respiratory acidosis within the first 4 hours after HFOV, then it began to improvement and get to normal at 48 hours after the initiation of HFOV, unfortunately it worsened again 72 hours later after HFOV. There were no significant changes in mean blood pressure, cardiac output associated with initiation and administration of HFOV.
Conclusions: High-frequency oscillatory ventilation was effective and safe in correcting oxygenation failure associated with ARDS in H1N1 patients.
