Final answer:
The next step, following the Rule of Threes, would be to check for proper mask seal.
Step-by-step explanation:
The next step, following the Rule of Threes, would be to check for proper mask seal. If the oxygen saturation levels remain lower than ideal, it could be due to a leak in the mask, preventing adequate oxygen delivery to the patient. Ensuring a proper mask seal will help improve ventilation and oxygenation.