Role of prophylactic azithromycin to reduce airway inflammation and mortality in a RSV mouse infection model.

BACKGROUND: Respiratory syncytial virus (RSV) infection is an important cause of morbidity and mortality in vulnerable populations. Macrolides have received considerable attention for their anti-inflammatory actions beyond their antibacterial effect. We hypothesize that prophylactic azithromycin will be effective in reducing the severity of RSV infection in a mouse model. METHODS: Four groups of BALB/c mice were studied for 8 days: Control (C), RSV-infected (R), early prophylaxis with daily azithromycin from days 1 to 8, (E), and late prophylaxis with daily azithromycin from days 4 to 8 (L). Mice were infected with RSV on day 4, except for the control group. All groups were followed for a total of 8 days when bronchoalveolar lavage cell count and cytokines levels were measured. Mouse weight, histopathology, and mortality data were obtained. RESULTS: Prophylactic azithromycin significantly attenuated post-viral weight loss between group R and both groups E and L (P = 0.0236, 0.0179, respectively). IL-6, IL-5, and Interferon-Gamma were significantly lower in group L (P = 0.0294, 0.0131, and 0.0056, respectively) compared with group R. The total cell count was significantly lower for group L as compared with group R (P < 0.05). Mortality was only observed in group R (8%). Lung histology in the prophylactic groups showed diminished inflammatory infiltrates and cellularity when compared with group R. CONCLUSION: Prophylactic azithromycin effectively reduced weight loss, airway inflammation, cytokine levels and mortality in RSV-infected mice. These results support the rationale for future clinical trials to evaluate the effects of prophylactic azithromycin for RSV infection.

Use of Nasal Non-Invasive Ventilation with a RAM Cannula in the Outpatient Home Setting.

BACKGROUND: Nasal non-invasive-ventilation (Nasal NIV) is a mode of ventilatory support providing positive pressure to patients via a nasal interface. The RAM Cannula is an oxygen delivery device that can be used as an alternative approach to deliver positive pressure. Together they have been successfully used to provide respiratory support in neonatal in-patient settings. OBJECTIVE: To describe the outpatient use of Nasal NIV/RAM Cannula as a feasible alternative for home respiratory support in children with chronic respiratory failure. METHODS: We performed a retrospective case series of 18 children (4 months to 19 years old) using the Nasal NIV/RAM Cannula in the Pediatric Pulmonary Clinic at the McGovern Medical School, UTHealth (2014-16). Consideration for Nasal NIV/RAM Cannula utilization included: inability to wean-off in-patient respiratory support, comfort for dyspnea, intolerability of conventional mask interfaces and tracheostomy avoidance. RESULTS: Average age was 7 years. 50% were Caucasian, 38% African-American and 11% Hispanics. Pulmonary disorders included: chest wall weakness (38%), central control abnormalities (33%), obstructive lung disease (16%) and restrictive lung disease (11%). Indications for Nasal NIV/RAM Cannula initiation included: CPAP/BPAP masks intolerability (11%), dyspnea secondary to chest wall weakness (38%) and tracheostomy avoidance (50%). Average length of use of Nasal NIV/RAM Cannula was 8.4 months. Successful implementation of Nasal NIV/Ram Cannula was 94%. One patient required a tracheostomy following the use of Nasal NIV/RAM Cannula. Significant decrease in arterial PaCO2 pre and post Nasal NIV/RAM cannula initiation was notable (p=0.001). CONCLUSION: Outpatient use of Nasal NIV/RAM Cannula may prove to be a feasible and save treatment alternative for children with chronic respiratory failure, chest wall weakness, dyspnea and traditional nasal/face mask intolerance to avoid tracheostomy.