Does nebulised acetylcysteine improve oxygen delivery in intubated Intensive Care Unit patients?

INTERVENTION: Nebulisation via ventilator circuit (or high flow circuit for tracheostomy patients) of 4ml of 20% acetylcysteine + 6ml of 0.9% NaCl until discontinuation of invasive respiratory support. Administration will be repeated every 6 hours. Adherence will be monitored by auditing drug charts CONDITION: Anaesthesiology ‐ Other anaesthesiology Respiratory ‐ Other respiratory disorders / diseases Ventilator Associated Pneumonia;Invasive Ventilation; ; Ventilator Associated Pneumonia ; Invasive Ventilation PRIMARY OUTCOME: Arterial partial pressure of oxygen vs Inhaled fraction of oxygen (PaO2/FiO2) ratio as assessed by arterial blood gas analysis[24 hours post enrolment] SECONDARY OUTCOME: Adverse events, e.g. bronchospasm. ; Collected contemporaneously on study document[During period of invasive ventilation, starting from study enrolment] Duration of hospital stay, from accessing electronic medical record[Assessed up to day 90 post study enrolment] Duration of ICU stay, collected from computerised medical records[Assessed up to 90 days post study recruitment] Duration of vasopressor/inotrope utilisation (composite outcome) by accessing patient medication charts[From time of enrolment to 28 days post‐enrolment] Highest Peak airway pressures as documented in the ICU observation chart[Over the first 24 hours after enrolment] Incidence of bronchospasm, as diagnosed based on increase in Peak airway pressure and presence of wheeze on clinical examination[During invasive ventilation] Incidence of renal replacement therapy utilistation, Data collected by accessing patient electronic medical record[From time of enrolment to 28 days post‐enrolment] Incidence of therapeutic bronchoscopy ; Collected contemporaneously on study form. [From time of enrolment to 28 days post‐enrolment] Incidence of ventilator associated pneumonia ; Collected contemporaneously on study form. ; [From time of enrolment to 28 days post‐enrolment] Mortality by accessing patient electronic medical record[Assessed at 90 days post‐enrolment] Number of complete days requiring invasive ventilation, Collected contemporaneously on study document[Measured up to day 28 after enrolment] Positive End Expiratory Pressure (PEEP) values by reviewing ICU observation charts[At 24 hours (time of ABG analysis for primary outcome) after enrolment] Pre‐specified subgroup analysis of patients with primary ICU admission diagnosis of respiratory sepsis/lower respiratory tract infection/pneumonia: ; Mortality by accessing patient electronic medical record[Assessed at 90 days post‐enrolment] Pre‐specified subgroup analysis of patients with primary ICU admission diagnosis of respiratory sepsis/lower respiratory tract infection/pneumonia: ; Ventilator Free Days. Collected contemporaneously on study form. ; [From time of enrolment to 28 days post‐enrolment] Primary Ventilator Mode, as recorded hourly on ICU observation charts[The Ventilator mode which was used for the greatest duration over the first 24 hours after enrolment (time of ABG analysis for primary outcome)] Reintubation rates. Collected contemporaneously on study form. [From time of enrolment to 28 days post‐enrolment] Subgroup analysis of patients of PaO2/FiO2 (as assessed by arterial blood gas analysis) INCLUSION CRITERIA: Receiving invasive ventilation and with moderate to high secretion burden ; in patients with primary ICU admission diagnosis of respiratory sepsis/lower respiratory tract infection/pneumonia[24 hours post enrolment] subjective secretion burden as recorded on ICU observation [During first 48 hours after study enrolment] Tracheostomy Rate Collected contemporaneously on study form. [From time of enrolment to 28 days post‐enrolment,] Ventilator Free Days. Collected contemporaneously on study form. [From time of enrolment to 28 days post‐enrolment]