Acute non-invasive ventilation – getting it right on the acute medical take

Abstract

Non-invasive ventilation (NIV) given to the right patient, in the right setting, in the right way and at the right time improves outcomes. However, national audits reveal poor practice in patient selection, clinical judgement, treatment initiation and availability of trained staff. NIV is indicated for persistent acute hypercapnic respiratory failure (AHRF) with acidosis after usual medical management in chronic obstructive pulmonary disease (COPD) exacerbation and even without acidosis in neuromuscular disorders or other restrictive conditions eg obesity hypoventilation or kyphoscoliosis. Having trained staff in a suitable environment with adequate equipment are keys to its success, along with close monitoring. A plan should be put in place at the time of initiating NIV about the ceiling of care, eg escalation to intubation or palliation, if the patient is not improving with NIV. Early NIV failure is most likely due to technical issues, such as inadequate pressures or mask leak, while late failure is usually the consequence of advanced disease. Any presentation with AHRF is a poor prognostic indicator and outpatient respiratory follow-up is indicated following discharge. For selected patients with COPD who remain hypercapnic 2 weeks after an exacerbation, domiciliary NIV can reduce admissions and improve survival. For patients with neuromuscular disorders or kyphoscoliosis a presentation with AHRF almost always indicates the need for domiciliary NIV.

Supporting patients with hypercapnia

“… 2 Ghosh et al described the importance of careful patient selection to optimise patient outcomes and summarised BTS/Intensive Care Society (ICS) guidelines in a recent review. 4 Thus, the evidence base for acute NIV indications will not be discussed further here. Before initiating NIV, discussions must be held with the patient and their caregivers regarding advanced care planning and their preferences regarding invasive mechanical ventilation and cardiopulmonary resuscitation in the event of NIV failure.…”

“… 2 , 3 When considering NIV initiation, careful patient selection is required, alongside appropriate titration and monitoring, to optimise patient outcomes. 4 In this review, we use a case study to provide a practical clinical guide to supporting patients with hypercapnic respiratory failure, to improve clinicians’ confidence in: recognising patients at risk of developing respiratory failure confirming the diagnosis and underlying aetiology appropriate application of NIV; troubleshooting NIV weaning from acute NIV and considering suitability for home mechanical ventilation (HMV). …”

The COVID-19 pandemic: the effect on airway Management in non-COVID emergency patients

“…Although the failure rate of NIV and HFNC was lower in the COVID period, this could have been due to a more appropriate patient selection and clinical judgement before treatment initiation in the COVID period. Previous evidences have shown high failure rates in places where NIV was not appropriately selected and initiated [ 19 , 20 ]. In addition, the lower failure rate in the COVID period could also have partly been due to the increasing trend of non-invasive airway support for palliative purposes over the past year.…”

Ventilation Strategies in Obese Patients

“…For ventilation devices with the possibility of setting the inspiratory and expiration ratio (I-E ratio), it is suitable to set it 1:2-1:1 [20].…”

“…• Inspiratory time: For mandatory breaths, 0.8-1.2 s according to breathing frequency. I-E ratio can be set 1:2-1:3 [20,23]. For ventilators with the possibility of setting the inspiratory ramp and rise time, it is advisable to set them so that the patient has enough time to inhale and, in the case of prolonged expiration, allow him/her to exhale effectively.…”