ABSTRACT
What is a pulse oximeter and what is it used for? What are the principles of pulse oximetry? What does pulse oximetry measure? How does the SaO2 relate to PO2 on ABGs? What other parameters need to be known to interpret a pulse oximeter reading? What are the pitfalls and sources of error in pulse oximetry? In what circumstances might the percentage saturation be erroneously high? What is methaemoglobin and how does its presence in the blood affect a pulse oximeter?
