see: [Dunn Non invasive ventilation](x-devonthink-item://AA18E4DA-06B2-4EC5-AC35-6BBAF9F83B64), [[Oxygen delivery devices FiO2]] #incomplete > [!key points] > - CPAP may improve oxygenation in T1 resp failure > - BiPAP preferred in Type II resp failure, especially COPD > > **initial settings** > - *APO* - > - *COPD* - **Indications** - respiratory failure caused by: - [[Pulmonary oedema|APO]] - [[COPD]] exacerbation - immunosuppression - role in [[Asthma]] uncertain/controversial **Advantages** - reduces need for intubation by ~25% overall - failure rate ~50% for hypoxic resp failure (eg pneumonia) - may reduce ICU LOS - enables treatment for patients who would not otherwise be suitable for intubation **disadvantages** - unable to be used in pts not breathing spontaneously or able to cooperate with pressure generator and mask - small amounts of ketamine may facilitate co-operation - aerosol-generating procedure - rarely effective in patients who are moribund from resp failure ## strategies to improve compliance - non-pharmacological: coaching, explanation, reassurance to patient - small titrated doses of analgesia eg fentanyl 20mcg - judicious ketamine eg 10mg aliquots IV Q5 min - judicious midazolam in 1mg aliquots Q5 min > note if significant agitation and not tolerating mask/deteriorating, would be indication for invasive ventilation # NIV in asthma NIV has some theoretical benefits in asthma: - extrinsic PEEP may help overcome intrinsic PEEP/"Auto-PEEP" and thus reduce inspiratory work of breathing - may increase tidal volume and minute ventilation - if tidal volume is ↑ with a shorter inspiratory time, then increased MV can occur without increasing dynamic hyperinflation - both PEEP and inspiratory augmentation may improve airspace opening and reduce V/Q mismatch. - may help splint spall airways open allowing expiration that are closed due to dynamic small airway closure with increased thoracic pressures settings: 5 CPAP + 8-10 PS > goal: <25 breaths/min and exhaled TV of 7mL/kg