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- COPD: pH < 7.35 AND PaC02 ≥ 6.5 RR > 23 despite one hour of medical management
- Neuromuscular Disease: Respiratory illness with RR >20 if usual VC <1L or pH < 7.35 AND PaC02 ≥ 6.5
- Obesity: pH < 7.35 AND PaC02 ≥ 6.5, RR > 23 or daytime PaC02 ≥ 6.0 and drowsy
NIV is not usually indicated in Asthma/ Pneumonia
Contraindications to NIV
- Severe facial deformity
- Facial burns
- Fixed upper airway obstruction
- pH <7.15
- pH <7.25 and additional adverse features
- GCS <8
- Cognitive impairment
- EPAP : 3 ( higher if OSA)
- IPAP: 15 (20 if PH and EPAP: 4 (higher in OSA)
- Increase IPAP over 10-30 minutes to 20-30 cmH20 (IPAP to not exceed 30 Or EPAP 8)
Alter NIV settings:
PaC02 Remains High: Persistent respiratory acidosis
- Is there too much oxygen? adjust Fi02 to target sat 88•92%.
- IS there leak? Should be Consider total mask.
- IS the patient rebreathing? Check the expiratory port is not occluded.
- Is the patient spending long enough on the machine? Address compliance issue
- Is the IPAP high enough? increase tidal volume (TV) by increasing IPAP
- Look at pervious used on previous admissions.
Paco2 Improved but Pa02 Low: Target Pao2 7
- Reassess for clinical deterioration; consider pneumothorax, aspiration , mucus pluging
- Increase Fi02
- Increase EPAP (remember you may need to increase IPAP to maintain TV)
- Consider senior review/ICU
- Arterial blood gas (ABG) analysis should be performed at baseline, 1 hour after commencing NIV, 4 hours after commencing NIV, and 1 hour after changing any settings
- If pH < 7.25 on optimal NIV, RR >25 continuously or new-onset confusion -> clinical review.
- Check synchronisation, mask fit, exhalation port. Consider chest physio, bronchodilators, anxiolytics, ICU
indication for ICU referral:
- AHRF (Acute Hypercapnic Respiratory Failure) in Asthma
- AHRF with impending respiratory arrest
- NIV treatment failure: decreased chest wall movement, unable to decrease PaC02
- Inability to maintain target Sp02 on NIV
- Need for IV sedation, closer monitoring
- +/- possible difficult intubation