Children's perception of breathlessness in acute asthma

Aim-To determine whether asthmatic children who present to hospital with hy poxia perceive breathlessness less well than non-hypoxic presenters. Methods-A total of 27 children aged 5-16 years (mean age 10) admitted with acute asthma had recordings of oxygen saturation (Sao(2)), clinical score, forced expiratory volume in one second (FEV1), and breathlessness score (HM P) at admission and at 5, 10, 24, 48, and 72 hours after admission. Those d efined as hypoxic (Sao(2) <92%) at admission were compared with a non-hypox ic group. Results-Twelve children were hypoxic at admission. Compared with the non-hy poxic group they were younger (8.6 (SD 2.8) v 11.2 (2.8) y, p = 0.02), and had greater airway obstruction (FEV, 32.5 (10)% v 54.3 (26)%, p = 0.0073, 9 5% confidence interval (CI) -36.9 to -6.6) yet had a trend towards less bre athlessness (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 rati o of change in HMP to change in FEV1 (Delta HMP/Delta FEV1) (median Delta H MP/Delta FEV1 0.021%(-1) v 0.073%(-1), p = 0.0081, CI -0.075 to -0.016). Li near regression analysis showed a strong relation between Delta HMP/Delta F EV1 and initial Sao(2) (p = 0.004, r = 0.54). Conclusions-Asthmatic children who present to hospital hypoxic tend to perc eive themselves as less breathless than non-hypoxic children. This may pred ispose to a future life threatening attack.