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Obtaining an arterial blood sample for blood gas analysis

Removal of a blood sample from an uncannulated artery.


– To determine arterial blood values of oxygen, carbon dioxide, oxygen saturation, and acid-base balance.


– Trough. – Compression forceps. – Sharps container.


– Sterile gauze. – Sterile gloves. – Antiseptic solution. – Insulin syringe. – Local anesthesia without vasodilator (optional). – 1 blood gas syringe. – Blood gas request form. – Nursing records.


– Wash hands. – Prepare the material. – Preserve the patient’s privacy. – Verify the correct identification of the patient. – Inform the patient of the procedure. – Ask for the patient’s cooperation. – Place the patient in a suitable position, sitting upright and keep him/her at rest for about 15 minutes. – Select the puncture artery: the artery of choice will be the radial artery at the level of the carpal tunnel, secondly the humeral artery at the level of the anticubital fossa and lastly the femoral artery at the inguinal level. – Palpate the chosen artery with the index and middle fingers. If the radial artery is used, the wrist should be placed in hyperextension, a rolled towel can be used. If the humeral artery is used, the arm should be placed in hyperextension. If the femoral artery is used, the patient should be placed in the supine position with the legs stretched out.

legs straight. If the radial artery is used, perform the Allen test (collateral circulation test). – Clean the area with antiseptic solution. – Allow to dry. – Put on sterile gloves. – Locate and fix the pulse with the index and middle fingers, with the other hand insert the needle into the artery at an angle of 45º to the wrist and 90º in the case of the humeral or femoral arteries. – Allow 1-2 ml of blood to enter. – Remove the needle and press the puncture site for 5 minutes. If humeral artery 7-8 minutes. If femoral 10 minutes. – Leave a dressing over the puncture site and fix it by lightly compressing it. – Eliminate air bubbles that may exist in the syringe. – Close the syringe and label with patient data. – Discard needle and sharp material in the container. – Place the patient in a comfortable position. – Collect the material. – Remove gloves. – Perform hand washing. – Record in the nursing documentation: procedure, reason, date and time, if oxygen carrier, incidences and patient response.


– The use of local anesthesia avoids pain, reduces anxiety and hyperventilation. If used: 1.Perform an infiltration of 0.3-0.5 ml. of local anesthesia without vasodilator, previously assessing that the patient does not have hypersensitivity to it. To do this, make a small intradermal infiltration, continue with a subcutaneous infiltration and finally make a deeper infiltration at a muscular level.2. – If the patient is anticoagulated or has coagulation disorders, maintain the pressure for 10 minutes. – If the sample is not sent immediately, keep it in a container with ice. – Allen test: Have the patient make a fist while the radial and ulnar artery is occluded. 2. 2. Instruct the patient to open his hand. 3. Stop compressing the ulnar artery. 4. The color should return to the patient’s hand within 15 seconds. If not, choose another site to perform the arterial puncture.

– Normal blood gas values: PO2: 80-100 mmHg. PCO2: 35-45 mmHg. PH: 7.35-7.45 mmHg. SaO2: 95-100 %.

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