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

Abstract

Background: The Norfolk and Norwich University Hospital (NNUH) is situa ted 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, FiO2 > 0.28) on COPD patients, and the outcome of instituting a simple protocol to reduce such exposure. Design: Retrospe ctive 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, FiO2 ≤ 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 PaO2 and PaCO2, 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 30min. 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. © The Author 2005. Published by Oxford University Press on behalf of the Association of Physicians. All rights reserved.