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Int J Clin Pract. 2012 May;66(5):434-7. doi: 10.1111/j.1742-1241.2012.02904.x.

Predicting survival following non-invasive ventilation for hypercapnic exacerbations of chronic obstructive pulmonary disease.

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Chest Clinic C, Aberdeen Royal Infirmary, Aberdeen, UK.



Non-invasive ventilation (NIV) has revolutionised the management of hypercapnic exacerbations of chronic obstructive pulmonary disease (COPD). We wished to evaluate factors related to its overall success in the 'real-life' setting.


A retrospective analysis of patients receiving NIV for a hypercapnic exacerbation of COPD was performed. Demographics, laboratory data, blood gases and outcomes (hospital discharge or in-patient death) were extracted and subsequently analysed to identify factors relating to its overall success or failure.


Over 6 years, 240 patients (mean age 70 years), received NIV with mean pH and pCO(2) prior to NIV 7.24 and 10.4kPa respectively; of these, 167 survived to hospital discharge with a median age (70 vs. 74; p = 0.02) lower than non-survivors. Absolute values of pH and pCO(2) (higher and lower respectively) prior to NIV and at 1 h were both associated with successful hospital discharge. An improvement (p = 0.02) in pH within an hour of receiving NIV - but not pCO(2) - was associated with surviving to hospital discharge. Of all laboratory data assessed, only baseline urea was significantly (p = 0.021) associated with a successful outcome.


Younger patients with a lower urea, higher pH and lower pCO(2) at baseline and who demonstrate an improvement in pH within 1 h, are more likely to have a successful outcome when given NIV for a hypercapnic exacerbation of COPD on an unselected basis. Prospective studies evaluating many other parameters are now required to help identify patients in whom NIV is likely to be successful.

[Indexed for MEDLINE]

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