Partial Pressure of Oxygen, Blood
(pO2)

Sample type

Whole blood (Heparin)

Uses

To evaluate patients with pulmonary or acid—base disturbances.

To monitor patients with carbon monoxide poisoning, methemoglobinemia, or hemoglobin variant for O2 saturation.

To manage patients on mechanical respirators. Prior to thoracic or general surgery.

Precautions

Drawing blood for this test takes about five minutes, but you should allot about an hour if you’re having the test done in an outpatient setting. This will give you time to register, wait for your turn, and ensure that the puncture site isn’t bleeding.

Interfering factors

Capillary blood is not suitable for estimation of high arterial pO2 values. Values measured at 37°C must be corrected to the actual temperature of the patient.

Drugs causing respiratory depression, for example, barbiturates, diazepam, heron, meperidine, and midazolam cause decrease in pO2.

Pre-analytical errors

1. If you receive a hemolyzed sample or unlabeled sample or you receive EDTA or citrate or oxalate plasma tubes

The corrective action

You should reject it and request for another sample

1. Gross hemolysis, mislabeled or unlabeled specimens

The corrective action

The sample should be rejected and another sample requested.

Post-analytical errors

I. reports were sent to the incorrect patient

The corrective action

communication with patient, apologizing for the error, and providing him with the correct report

II. write the wrong name in the report or the wrong results.

The corrective action

If the report is not delivered to the patient and this error is discovered, the correct result or the correct name must be written, but if the report is delivered to the patient, you must communicate with him, apologies to him, and tell him that an error has occurred and replace it with the correct report.

Reference range

• Arterial: 35-45 mm Hg

• Venous: 35-40 mm Hg