An experimental study involving repeated-measures within subjects was conducted to examine the effects of shallow and deep endotracheal suctioning (ETS) on the SpO(2) and HR in 27 ventilated high-risks infants. The order in which subjects received the ETS protocol was randomly assigned. The results showed no significant changes in both the SpO(2) and HR responses before, during and after ETS between the two ETS protocols. It is concluded that when there is no beneficial effect of performing deep ETS, it should not be carried out due to the potential hazard of direct irritation with more negative pressure on the airways in high-risk infants.