Initial oxygen management in patients with an exacerbation of chronic obstructive pulmonary disease.

BACKGROUND

The Norfolk and Norwich University Hospital (NNUH) is situated in rural Norfolk, and ambulance journey times are often >30 min. Longer ambulance journeys could lead to a greater risk of hypercapnia, if inappropriately high concentrations of oxygen are given during an exacerbation of COPD.

AIM

To investigate the effect of high concentration oxygen (HCO, FiO(2) > 0.28) on COPD patients, and the outcome of instituting a simple protocol to reduce such exposure.

DESIGN

Retrospective audit.

METHOD

An audit was conducted of all patients admitted with an exacerbation of COPD to the NNUH during the 2 months from 1 December 2001 to 31 January 2002 (n = 108). Results were shared with paramedics, and guidelines agreed for the initial provision of lower concentrations of oxygen (LCO, FiO(2) < or = 0.28). A second audit was conducted a year later between 1 December 2002 and 31 January 2003 (n = 103).

RESULTS

HCO caused significant (p < 0.01) acidosis and inappropriately high PaO(2) and PaCO(2), compared to initial LCO therapy. There was a significantly increased complication rate during admission (p < 0.01) in those COPD patients receiving HCO compared to LCO, particularly when ambulance journeys exceeded 30 min. The second audit demonstrated a significant (p < 0.001) reduction in the number of patients initially receiving HCO, but the complication rate was unaltered.

DISCUSSION

A simple intervention, such as providing paramedics with 28% Venturi masks, can reduce the number of COPD patients exposed to HCO. A randomized controlled trial is long overdue to establish whether HCO or LCO as initial management is associated with the most favourable prognosis in different hospital settings.