Association between preoperative haemoglobin concentration and cardiopulmonary exercise variables: a multicentre...

Area of Science:

• Cardiopulmonary Exercise Testing
• Anesthesiology
• Internal Medicine

Background:

• Preoperative anemia and reduced exertional oxygen uptake are linked to increased postoperative complications.
• Understanding the relationship between hemoglobin and exercise capacity is crucial for surgical risk assessment.

Purpose of the Study:

• To investigate the association between preoperative hemoglobin concentration ([Hb]), peak oxygen uptake (V˙O2 peak), and anaerobic threshold (AT) in elective surgical patients.

Main Methods:

• A cohort of 1,777 preoperative patients underwent preoperative [Hb] measurement and cardiopulmonary exercise testing between 1999 and 2011.
• Linear regression and covariance analyses were used to examine the associations between [Hb], V˙O2 peak, and AT.

Main Results:

• 24.5% of patients had [Hb] <12 g dl-1, with 83 having [Hb] <10 g dl-1.
• Both AT and V˙O2 peak increased with higher [Hb] (r2 = 0.24 and r2 = 0.30, respectively).
• A one standard deviation increase in [Hb] correlated with a 6.7–9.7% increase in V˙O2 peak and a 4.4–6.0% rise in AT, with [Hb] accounting for 9% and 6% of variation in V˙O2 peak and AT, respectively.

Conclusions:

• Lower preoperative hemoglobin concentrations are independently associated with reduced oxygen uptake during cardiopulmonary exercise testing.
• The findings suggest a modest link between anemia and impaired exercise capacity in the preoperative surgical setting.
• Causality of this association remains to be determined.