IEC 60601-2-23:2011 applies to the basic safety and essential performance of transcutaneous partial pressure monitoring equipment. It applies to transcutaneous monitors used with adults, children and neonates, and it includes the use of these devices in foetal monitoring during birth. IEC 60601-2-23:2011 does not apply to haemoglobin saturation oximeters or to devices applied to surfaces of the body other than the skin (for example conjunctiva, mucosa). This third edition cancels and replaces the second edition published in 1999 and constitutes a technical revision. This edition of IEC 60601-2-23 was revised to align structurally with the 2005 edition of IEC 60601-1.