MRCP2-4482

MRCP2-4482

A 67 year old woman presents to the emergency department with a 4 day history of worsening shortness of breath and cough. She has a history of COPD and is being treated for an infective exacerbation. She also has a past medical history of hypertension, type 2 diabetes mellitus, hypercholesterolaemia, hypothyroidism, osteoarthritis and depression.

Despite nebulisers, steroids and antibiotics, she remains acutely breathless and her oxygen saturations are only 84% on air. Blood gas analysis shows:

pH 7.22
pCO2 10.3 kPa
pO2 7.1 kPa
BE -4.5 mmol/l
HCO3- 36 mEq/l

The decision is made to try NIV and she is transferred to the NIV unit. Initial settings on NIV are IPAP 8 cm H2O and EPAP 4 cm H2O. However, she remains tachypnoeic and has oxygen saturations of 87%. Her repeat blood gas after 1 hour is as follows:

pH 7.26
pCO2 9.8 kPa
pO2 9.5 kPa
BE -3.8 mmol/l
HCO3- 35 mEq/l

What adjustments would you make to the NIV settings?