An implementation-effectiveness trial to evaluate physiotherapy guideline care in practice and determine whether a course of protocolised physiotherapy ventilator lung hyperinflation treatment, added to guideline care, is feasible, safe, cost-effective and improves patient-important outcomes for ICU patients with severe pneumonia requiring invasive mechanical ventilation.

Guideline physiotherapy care according to van der Lee et al (2024) incorporating a modified ventilator hyperinflation (VHI) treatment by Jacob et al 2021, performed by ICU physiotherapists, at a set daily dosage and frequency of 3 times per day. The VHI technique described by Jacob et al (2021) is based on the individual patient’s estimated inspiratory reserve volume (IRV), to determine the target increase in tidal volume above resting tidal volume which would be safe to deliver to the patient via the ventilator to simulate a deep breath, for the purpose of recruiting atelectatic alveoli via collateral channels to mobilise sputum which can then be cleared via airway suctioning. The following formulae will be used to calculate the estimated IRV as per Jacob et al (2021), using Microsoft Excel, based on each patient’s age, height and weight up to a Body Mass Index (BMI) of 25. Predicted body weight (BMI 25) was used for patients who were overweight or obese. Estimated IRV (male) =2.89 x height + 0.016 x age - 0.032 x weight - 12.69 Estimated IRV (female) = 1.72 × height - 0.016 x age - 0.022 x weight - 4.91 Patients who are randomised to receive the new VHI treatment will receive four sets of eight to ten breaths, three times per day until extubation or Day 28 in ICU, whichever occurs first. The patient will receive eight to ten breaths per cycle to minimise hyperventilation. An inspiratory time of 3-5 seconds will be used. In this study, the determined target hyperinflation volume will be limited at a peak pressure of 40cmH2O, which multiple studies have shown to be both effective and safe. Peak pressure is monitored continuously on the ventilator display and reviewed by treating clinicians. The VHI treatment will be delivered via the patient’s mechanical ventilator using a volume-controlled mode with a decelerating flow pattern, which is pressure limited, with alarms set accordingly to allow the delivery of the treatment VHI breath set to a maximum inspiratory pressure of 40 cmH2O. For patients who have progressed to breathing spontaneously on the ventilator without the need for mandatory ventilator breaths, or who have difficulty with ventilator synchrony, the VHI treatment may be performed using a pressure-support mode of ventilation, where all breaths are triggered by the patient and pressure support is provided to deliver the target volume by the ventilator above the patient’s own breathing effort, up to a pressure limit of 40cmH2O. Research has shown this to be an effective and safe method of delivering VHI treatment in this context and improves patient-ventilator synchrony in patients who are weaning. Data will be collected at the bedside by the treating clinician regarding each episode of treatment delivered, including the time of treatments, dosage delivered (number of sets and repetitions of breaths), ventilator parameters during treatment, and target and achieved tidal volumes and inspiratory pressures in order to evaluate treatment adherence and fidelity. Active respiratory physiotherapy treatment, comprising deep breathing exercises and coughing, will be performed daily at a minimum, between extubation and ICU discharge as per guideline care. Once awake and able to participate actively in rehabilitation, muscle strengthening and early mobilisation will be standardised to 20 minutes per day between groups and based on patient’s highest level of function according to the ICU Mobility Scale (IMS).