Jet or Vibrating Mesh Nebulisation for Secretion Management in ICU

Can Continuous or Intermittent Normal Saline Nebulisation Via a Vibrating Mesh Nebuliser or Intermittent Normal Saline Via a Standard Jet Nebuliser Improve the Lung Physiology and Secretion Viscosity in Mechanically Ventilated Patients?

Critically unwell patients in Intensive Care have a decreased ability to effectively clear secretions. High secretion load is a major risk factor in the failure of tracheal extubation failure and the requirement for reintubation. Extubation failure is a predictor of poor outcome independent of the severity of the underlying illness. Nebulisation of isotonic saline can be employed to manage secretions by reducing the secretion viscosity and facilitating clearance of respiratory sections during tracheal suction. Standard jet nebulisers have been the mainstay of respiratory section management therapy in critical care since the early 1990s. A more recent development has been the vibrating mesh nebuliser. There is evidence of improved humidification and reduced water particle size and theoretically better transfer to the distal airways.

1.2 Rationale The vibrating mesh nebuliser (Aerogen technology) may be superior to standard nebuliser technology. 1.3 Study hypothesis Improved secretion management with reduced tenacity of respiratory sections and potentially improved lung physiology secondary to improved humidification or reduced size of nebulised particles? 2. STUDY OBJECTIVES Primary Endpoint Pourability of respiratory secretions (As assessed by the Qualitative Sputum Assessment Tool) (The QSA score will assess quantity, quality/stickiness/density and colour/appearance of secretions and is described and validated in the literature3,4) Secondary endpoints Volume of secretions (increased or decreased may be beneficial) Work of breathing Airway resistance Number of number of additional nebulised doses of saline or other drugs administered during the study period Ease of sampling, in the opinion of treating nurse Frequency of requiring changing the HME(heat and moisture exchange) filter Length of time on ventilator Length of stay in ICU/HDU(Intensive care unit/high dependancy unit) ICU Mortality 3. STUDY DESIGN 3.1 Study Population A total of 60 patients will be recruited to the study. Each patient will be randomised to receive: Continuous nebulisation of 0.9% normal saline using the Aerogen Solo Nebuliser (50mls/24h via a syringe feed set) OR Intermittent nebulisation of 0.9% normal saline using the Aerogen Solo Nebuliser (5mls, 6 hourly) OR Intermittent standard nebulisation of 0.9% normal saline using the Intersurgical Cirrus 2 self-sealing Jet Nebuliser (5 mls, 6 hourly)

Continuous nebulization of 0.9% normal saline using the Aerogen Solo Nebuliser (50mls/24h continuous infusion using a syringe pump)

Intermittent nebulization of 0.9% normal saline using the Aerogen Solo Nebuliser (5mls 0.9% normal saline nebulised every 6 hours)

Intermittent standard nebulization of 0.9% normal saline using the Intersurgical Cirrus 2 self-sealing Jet Nebuliser ((5mls 0.9% normal saline nebulised every 6 hours)

Intermittent standard intermittent nebulisation of 0.9% saline Intersurgical Cirrus 2 self sealing Jet Nebuliser

standard intermittent nebulisation of 0.9% saline using the Intersurgical Cirrus 2 self-sealing Jet Nebuliser

Pourability of respiratory secretions (The QSA score will assess quantity, quality/stickiness/density and colour/appearance of secretions and is described and validated in the literature3,4)

Pourability of respiratory secretions as assessed by the QSA (Qualitative Sputum Assessment) Tool 0-4. . As the QSA Tool score ranges from 1 to 4 in increments of 0.5, with 1 being the most pourable and 4 the least pourable. (The QSA score will assess quantity, quality/stickiness/density and colour/appearance of secretions and is described and validated Lopez-Vidriero MT, Charman J, Keal E, De Silva DJ, Reid L. Sputum viscosity: correlation with chemical and clinical features in chronic bronchitis. Thorax. 1973 Jul;28(4):401-8. PubMed ID: 4741442

Number of number of additional nebulised doses of saline or other drugs administered during the study period

Qualitative assessment scale 1-10 . 1 very easy to sample-10 very difficult to obtain a sputum sample.

Inclusion Criteria: Patient aged 18-80 years at time of recruitment to study Ventilated via an endotracheal tube or tracheostomy with an HME filter in the circuit Secretion load defined as patient requiring suctioning at least 2 times in the 6 hours prior to recruitment Sputum viscosity with grades 1 to 3 pourability in the Qualitative Sputum Assessment tool Not yet received saline nebulisation in the 6 hours prior to recruitment Likely to be ventilated via an endotracheal tube or tracheostomy for at least 3 days in the opinion of the treating clinician Exclusion Criteria: Pregnancy Pulmonary embolus Heart Failure (NYHA Grade III/IV) Clinical evidence of frank pulmonary oedema Cardiovascular instability (systolic BP ≤75 or heart rate ≥140)

Thille AW, Richard JC, Brochard L. The decision to extubate in the intensive care unit. Am J Respir Crit Care Med. 2013 Jun 15;187(12):1294-302. doi: 10.1164/rccm.201208-1523CI.

Terzi N, Guerin C, Goncalves MR. What's new in management and clearing of airway secretions in ICU patients? It is time to focus on cough augmentation. Intensive Care Med. 2019 Jun;45(6):865-868. doi: 10.1007/s00134-018-5484-2. Epub 2018 Dec 5. No abstract available.

Jaber S, Quintard H, Cinotti R, Asehnoune K, Arnal JM, Guitton C, Paugam-Burtz C, Abback P, Mekontso Dessap A, Lakhal K, Lasocki S, Plantefeve G, Claud B, Pottecher J, Corne P, Ichai C, Hajjej Z, Molinari N, Chanques G, Papazian L, Azoulay E, De Jong A. Risk factors and outcomes for airway failure versus non-airway failure in the intensive care unit: a multicenter observational study of 1514 extubation procedures. Crit Care. 2018 Sep 23;22(1):236. doi: 10.1186/s13054-018-2150-6.

Keal EE, Reid L. Neuraminic acid content of sputum in chronic bronchitis. Thorax. 1972 Nov;27(6):643-53. doi: 10.1136/thx.27.6.643.

Lopez-Vidriero MT, Charman J, Keal E, De Silva DJ, Reid L. Sputum viscosity: correlation with chemical and clinical features in chronic bronchitis. Thorax. 1973 Jul;28(4):401-8. doi: 10.1136/thx.28.4.401.

Julious SA. Sample size of 12 per group rule of thumb for a pilot study. Pharmaceutical Statistics 2005; 4(4): 287-291.