Venous gas in COPD exacerbation

Prolific emergency medicine researcher Anne-Maree Kelly and colleague Dr Lim from Tan Tock Seng Hospital in Singapore have published a systematic review of articles assessing the utility of peripheral venous blood gases (pVBG) in exacerbations of COPD1. Their conclusion:

Available evidence suggests that there is good agreement for pH and HCO3 values between arterial and pVBG results in patients with COPD, but not for pO2 or pCO2. Widespread clinical use is limited because of the lack of validation studies on clinical outcomes

pVBG may however be useful as a screening test for significant arterial hypercarbia; Kelly et al. previously reported2 a cutoff value of 45 mmHg (5.9 kPa).

1. A meta-analysis on the utility of peripheral venous blood gas analyses in exacerbations of chronic obstructive pulmonary disease in the emergency department
Eur J Emerg Med. 2010 Oct;17(5):246-8

2. Kelly AM, Kerr D, Middleton P. Validation of venous pCO2 to screen for arterial hypercarbia in patients with chronic obstructive airways disease.
J Emerg Med 2005; 28:377–379