High-Frequency Percussive Ventilation in Viral Bronchiolitis.

BACKGROUND: High-frequency percussive ventilation (HFPV) is an alternative mode of mechanical ventilation that has been shown to improve gas exchange in subjects with severe respiratory failure. We hypothesized that HFPV use would improve ventilation and oxygenation in intubated children with acute bronchiolitis. METHODS: In this single-center prospective cohort study we included mechanically ventilated children in the pediatric ICU with bronchiolitis 1-24 months old who were transitioned to HFPV from conventional invasive mechanical ventilation from November 2018-April 2020. Patients with congenital heart disease, on extracorporeal membrane oxygenation (ECMO), and with HFPV duration < 12 h were excluded. Subject gas exchange metrics and ventilator parameters were compared before and after HFPV initiation. RESULTS: Forty-one of 192 (21%) patients intubated with bronchiolitis underwent HFPV, and 35 met inclusion criteria. Median age of cohort was 4 months, and 60% were previously healthy. All subjects with available oxygenation saturation index (OSI) measurements pre-HFPV met pediatric ARDS criteria (31/35, 89%). Mean CO2 decreased from 65.4 in the 24 h pre-HFPV to 51 (P < .001) in the 24 h post initiation. SpO2 /FIO2 was significantly improved at 24 h post-HFPV (153.3 to 209.7, P = .001), whereas the decrease in mean OSI at 24 h did not meet statistical significance (11.9 to 10.2, P = .15). The mean peak inspiratory pressure (PIP) decreased post-HFPV from 29.7 to 25.0 at 24 h (P < .001). No subjects developed an air leak or hemodynamic instability secondary to HFPV. Two subjects required ECMO, and of these, one subject died. CONCLUSIONS: HFPV was associated with significant improvement in ventilation and decreased exposure to high PIPs for mechanically ventilated children with bronchiolitis in our cohort and had a potential association with improved oxygenation. Our study shows that HFPV may be an effective alternative mode of ventilation in patients with bronchiolitis who have poor gas exchange on conventional invasive mechanical ventilation.

High-Frequency Oscillatory Ventilation for Refractory Hypoxemia in Severe COVID-19 Pneumonia: A Small Case Series.

BACKGROUND COVID-19 continues to place a tremendous burden on the healthcare system, with most deaths resulting from respiratory failure. Management strategies have varied, but the mortality rate for mechanically ventilated patients remains high. Conventional management with ARDSnet ventilation can improve outcomes but alternative and adjunct treatments continue to be explored. High-frequency oscillatory ventilation (HFOV), a modality now rarely used in adult critical care medicine, may offer an alternative treatment option by maximizing lung protection and limiting oxygen toxicity in critically ill patients failing conventional ventilator strategies. CASE REPORT We present 3 patients with severe acute respiratory distress syndrome (ARDS) and sepsis due to COVID-19 who all improved clinically after transitioning from conventional ventilation to HFOV. Two patients developed refractory hypoxemia with hemodynamic instability and multiple organ failure requiring vasopressor support and renal replacement therapy. After failing to improve with all available therapies, both patients stabilized and ultimately improved after being placed on HFOV. The third patient developed severe volutrauma/barotrauma despite extreme lung protection and ARDSnet ventilation. He showed improvement in oxygenation and signs of lung trauma slowly improved after initiating HFOV. All 3 patients were ultimately liberated from mechanical ventilation and discharged from the hospital to return to functional independence. CONCLUSIONS Our experience suggests that HFOV offers advantages in the management of certain critically ill patients with ARDS due to COVID-19 pneumonia and might be considered in cases refractory to standard management strategies.

Intermittent High-Frequency Percussive Ventilation Therapy in 3 Patients with Severe COVID-19 Pneumonia.

BACKGROUND High-frequency percussive ventilation (HFPV) is a method that combines mechanical ventilation with high-frequency oscillatory ventilation. This report describes 3 cases of patients with severe COVID-19 pneumonia who received intermittent adjunctive treatment with HFPV at a single center without requiring admission to the Intensive Care Unit (ICU). CASE REPORT Case 1 was a 60-year-old woman admitted to the hospital 14 days after the onset of SARS-CoV-2 infection symptoms, and cases 2 and 3 were men aged 65 and 72 years who were admitted to the hospital 10 days after the onset of SARS-CoV-2 infection symptoms. All 3 patients presented with clinical deterioration accompanied by worsening lung lesions on computed tomography (CT) scans after 21 days from the onset of symptoms. SARS-CoV-2 infection was confirmed in all patients by real-time reverse transcription-polymerase chain reaction (RT-PCR) assay from nasal swabs. All 3 patients had impending respiratory failure when non-invasive intermittent HFPV therapy was initiated. After therapy, the patients had significant clinical improvement and visibly decreased lung lesions on followup CT scans performed 4-6 days later. CONCLUSIONS The 3 cases described in this report showed that the use of intermittent adjunctive treatment with HFPV in patients with severe pneumonia due to infection with SARS-CoV-2 improved lung function and may have prevented clinical deterioration. However, recommendations on the use of intermittent HFPV as an adjunctive treatment in COVID-19 pneumonia requires large-scale controlled clinical studies. In the pandemic context, with a shortage of ICU beds, avoiding ICU admission by using adjunctive therapies on the ward is a useful option.