Potential Therapeutic Applications of Pulmonary Surfactant Lipids in the Host Defence Against Respiratory Viral Infections.

Pulmonary surfactant is a complex and highly surface-active material. It covers the alveolar epithelium and consists of 90% lipids and 10% proteins. Pulmonary surfactant lipids together with pulmonary surfactant proteins facilitate breathing by reducing surface tension of the air-water interface within the lungs, thereby preventing alveolar collapse and the mechanical work required to breathe. Moreover, pulmonary surfactant lipids, such as phosphatidylglycerol and phosphatidylinositol, and pulmonary surfactant proteins, such as surfactant protein A and D, participate in the pulmonary host defense and modify immune responses. Emerging data have shown that pulmonary surfactant lipids modulate the inflammatory response and antiviral effects in some respiratory viral infections, and pulmonary surfactant lipids have shown promise for therapeutic applications in some respiratory viral infections. Here, we briefly review the composition, antiviral properties, and potential therapeutic applications of pulmonary surfactant lipids in respiratory viral infections.

Surfactant therapy for COVID-19 related ARDS: a retrospective case-control pilot study.

BACKGROUND: COVID-19 causes acute respiratory distress syndrome (ARDS) and depletes the lungs of surfactant, leading to prolonged mechanical ventilation and death. The feasibility and safety of surfactant delivery in COVID-19 ARDS patients have not been established. METHODS: We performed retrospective analyses of data from patients receiving off-label use of exogenous natural surfactant during the COVID-19 pandemic. Seven COVID-19 PCR positive ARDS patients received liquid Curosurf (720 mg) in 150 ml normal saline, divided into five 30 ml aliquots) and delivered via a bronchoscope into second-generation bronchi. Patients were matched with 14 comparable subjects receiving supportive care for ARDS during the same time period. Feasibility and safety were examined as well as the duration of mechanical ventilation and mortality. RESULTS: Patients showed no evidence of acute decompensation following surfactant installation into minor bronchi. Cox regression showed a reduction of 28-days mortality within the surfactant group, though not significant. The surfactant did not increase the duration of ventilation, and health care providers did not convert to COVID-19 positive. CONCLUSIONS: Surfactant delivery through bronchoscopy at a dose of 720 mg in 150 ml normal saline is feasible and safe for COVID-19 ARDS patients and health care providers during the pandemic. Surfactant administration did not cause acute decompensation, may reduce mortality and mechanical ventilation duration in COVID-19 ARDS patients. This study supports the future performance of randomized clinical trials evaluating the efficacy of meticulous sub-bronchial lavage with surfactant as treatment for patients with COVID-19 ARDS.

The effect of surfactant on clinical outcome of patients with COVID-19 under mechanical ventilation: A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: Assessing the effect of surfactant on clinical outcome in patients with COVID-19 under mechanical ventilation TRIAL DESIGN: Single centre, two arm, parallel group (1:1 allocation ratio), randomised superiority trial with blinded care and outcome assessment. PARTICIPANTS: Inclusion criteria: Adult COVID-19 patients admitted to the ICU in Modarres hospital, Tehran, Iran (age range of 18 to 99 years) with moderate to severe ARDS (based on definition of P/F ratio) requiring auxiliary respiratory devices (either intubation or face mask). EXCLUSION CRITERIA: ● Existence of a major underlying pulmonary disease in addition to COVID-19 ● Underlying congenital heart disease ● Patients needing extracorporeal membrane oxygenation (ECMO) ● ARDS primarily due to any other reason rather than COVID-19 ● The primary source of pulmonary involvement was bacterial pneumonia or any other etiology except for COVID-10 induced lung involvement ● Those who refused to continue the study (either the patient or their family) ● any patient had any sign of healing before entering the study leading to discharge from ICU in less than 12 hours INTERVENTION AND COMPARATOR: In the intervention group, the dose of the drug is a vial containing 4 ml, equivalent to 100 mg, which is prescribed for an adult weighing about 70 kg each time, and if the patient's weight is much lower or higher, it will be adjusted accordingly. Surfactant is prescribed inside the trachea in two doses, starting on the day of intubation with a second dose 6 hours later. The control group will receive the same volume of normal saline, based on weight, administered into the trachea with the same time schedule. MAIN OUTCOMES: 30 days mortality; patient mortality during stay in ICU up to 30 days; ICU length of stay up to 30 days; Time under mechanical ventilation up to 30 days. RANDOMISATION: After the participant enters the study, i.e. after the qualification of the patients in the trial is confirmed and their informed written consent is taken, we will use a simple randomisation method using a table of random numbers. In order to hide the random allocation process, a central randomisation approach will be used and the random sequence will be at the disposal of one of the researchers, excluding the principal investigator. BLINDING (MASKING): Participants, healthcare providers and the principal investigator assessing the outcomes will all be blinded to the group assignment. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): A total of 60 participants will be randomised in a 1:1 allocation ratio (30 patients allocated to the intervention group and 30 patients allocated to the control group). TRIAL STATUS: The protocol is Version 1.0, May 31, 2020. Recruitment began July 30, 2020, and is anticipated to be completed by October 30, 2020. TRIAL REGISTRATION: IRCT registration number: IRCT20091201002804N12 Registration date: 1st June 2020, 1399/03/12 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.