Jugular venous and brain tissue oxygen tension monitoring

Ultrasound-guided internal jugular vein oxygen saturation (SjvO ₂ ) catheter placement: Before the procedure

Anatomy

The cerebral venous sinuses drain out of the skull through the jugular foramina and into the internal jugular veins. Immediately distal to the jugular foramen, the vein dilates, forming the jugular venous bulb. The cerebral and cerebellar veins and the veins of the brainstem all open into major sinuses (e.g., superior sagittal; inferior sagittal; straight, right, and left transverse; and occipital sinuses); these terminate in the right and left sigmoid sinuses, which curve downward into a deep groove on the mastoid part of the temporal bone. Finally, they turn forward in the posterior aspect of the jugular foramen to become the jugular bulb of the internal jugular vein.

The trachea is in the midline descending to the sternal notch. The two heads of the sternocleidomastoid muscle and the clavicle form a triangle at the anterior neck. The internal jugular vein may be accessed through this triangle, approximately 2–3 cm above the clavicle. Performing a venous puncture higher in the triangle reduces the risk of pneumothorax and allows for better arterial compression in the case of an inadvertent puncture of the carotid artery.

Procedure

See Video E19.1 .

• Continuous electrocardiography (ECG), blood pressure measurement, and pulse oximetry

• Place the patient in the Trendelenburg position to increase jugular filling and reduce the possibility of an air embolism. (Note: Trendelenburg positioning should be minimized as much as possible to avoid undesired elevations of ICP.)

• Rotate the patient’s head slightly to the contralateral side of the chosen site if there is no evidence of cervical spine injury.

• Perform an ultrasound survey to assess the location and patency of the jugular vein and to determine whether one side has dominant flow (i.e., larger jugular vein). Catheter placement is easier, and continuous oxygen saturation measurements will usually be better on the side with the greater blood flow.

• The common carotid artery and the internal jugular vein should be easily identified. The common carotid artery is seen as a pulsating, noncompressible, rounded structure. The internal jugular vein is larger, easily compressible, and nonpulsatile. Ensure that the internal jugular vein is patent by gently compressing the vein with the transducer (Note: slight pressure is sufficient to collapse the lumen of the internal jugular vein). Orienting the transducer in a cross-sectional plane during the ultrasound examination facilitates interpretation of the resulting images. Usually, ultrasound probes have a marker on one side that corresponds to the same side of the image on the screen. This helps the operator identify the correct orientation of the image.

• After identification of an acceptable site for cannulation, recruit an assistant.

• Follow universal precautions when placing a jugular venous line.

• Prepare the skin using a chlorhexidine-based antiseptic, and cover the area with a sterile fenestrated drape. Iodine can be used in patients with hypersensitivity to chlorhexidine.

• To prepare the ultrasound probe, have the assistant dispense enough acoustic gel onto a sterile transducer sheath to cover the transducer surface inside the sheath.

• The assistant carefully feeds the probe into the sheath and through the gel while extending the sterile sheath away from the operator over the length of the probe wire. Eliminate any wrinkles in the sheath and any air bubbles between the transducer and the sheath. Place the rubber bands to secure the cover sheath in place. To complete the acoustic coupling, apply a small amount of sterile ultrasound gel to the covered ultrasound probe or the patient’s skin.

• Identify a convenient sterile area on which the probe can be placed when not in use.

• Position the transducer perpendicular to the skin so that the internal jugular vein is centered in the resulting ultrasound image and between the two heads of the sternocleidomastoid muscle. The ultrasound probe should be held in the nondominant hand.

• Gently palpate the skin to confirm that the puncture will occur between the muscle heads and not through one of the heads.

• Using an 18-gauge needle, puncture the skin just below the transducer, being careful not to damage the sterile sheath.

• Slowly advance the needle at a 30- to 45-degree angle in an upward direction (cephalad) while watching the ultrasound screen. As the needle is advanced, negative pressure is maintained in the syringe until the vein is punctured and blood return is obtained. The needle will appear as a hyperechogenic shadow.

• If you do not aspirate blood as the needle is advanced, slowly withdraw the needle while gently maintaining negative pressure. The venous puncture may become evident upon needle withdrawal. Occasionally, pressure from the ultrasound probe may compress the vein, making it difficult to enter the vessel.

• As soon as the blood is freely aspirated, place the probe in the predetermined sterile area, stabilize the needle, and disconnect the syringe.

• Confirm that the blood flow is nonpulsatile. If possible, transduce blood pressure with the transducer line that is usually provided with the catheter kit.