An Ohio parent’s quick guide to blood gases in sick babies

March 30, 2023 | Crandall & Pera Law
An Ohio parent’s quick guide to blood gases in sick babies

While not telling the whole story, blood gas levels hold vital clues to a baby in an Ohio neonatal intensive care unit’s acid-base balance and oxygenation status. These numbers can vary significantly from those found in older children and help determine if the baby needs to have its ventilator adjusted or is ready to try breathing independently.


A baby’s pH level should be between 7.35 and 7.45. This number tells doctors how well the baby’s cells are performing, and it can hold vital clues to how well the lungs and kidneys are functioning or if there are birth injuries.

Partial pressure of arterial carbon dioxide

Often abbreviated as PaCO2, this number should be between 4.5 and 8.5 kilopascals on babies less than three days old and between 3 and 10 kilopascals on older babies. Doctors use it to indicate how well the baby’s body gets rid of carbon dioxide and uses oxygen. Normally, there is a correlation between this number and the pH number.

Partial pressure of oxygen

Often abbreviated as PaO2, this number indicates how well the baby’s body uses oxygen and must be obtained from arterial blood. If the mother carried the baby to term, this number should be between 7.0 and 12.0 kilopascals, but if the baby came early, it should be between 6.5 and 10.5.


Healthcare providers do a series of mathematical equations to arrive at this number that tells them the bicarbonate level in the baby’s blood. This number should be between 22 and 26 milliequivalents per liter in babies carried to term and between 20 and 24 in premature babies. Doctors use this number to spot metabolic acidosis when a baby has used all its neutralizing acids. Doctors working with sick babies use blood gases to tell them how well the baby’s body is performing.