AIM To determine whether asthmatic children who present to hospital with hypoxia perceive breathlessness less well than non-hypoxic presenters.

RESULTS Twelve children were hypoxic at admission. Compared with the non-hypoxic group they were younger (8.6 (SD 2.8) v 11.2 (2.8) y, p = 0.02), and had greater airway obstruction (FEV₁ 32.5 (10)% v 54.3 (26)%, p = 0.0073, 95% confidence interval (CI) −36.9 to −6.6) yet had a trend towards less breathlessness (median HMP 4 v 3, p = 0.062, CI −0.001 to 2.00) at admission. The hypoxic group had a smaller change in breathlessness from admission to discharge, despite a similar improvement in FEV₁, reflected in a lower ratio of change in HMP to change in FEV₁(ΔHMP/ΔFEV₁) (median ΔHMP/ΔFEV₁0.021%⁻¹ v0.073%⁻¹, p = 0.0081, CI −0.075 to −0.016). Linear regression analysis showed a strong relation between ΔHMP/ΔFEV₁ and initial Sao ₂(p = 0.004, r = 0.54).

CONCLUSIONS Asthmatic children who present to hospital hypoxic tend to perceive themselves as less breathless than non-hypoxic children. This may predispose to a future life threatening attack.