Today our topic of discussion is Cerebral Blood Flow Monitoring.
Cerebral Blood Flow Monitoring
CEREBRAL BLOOD FLOW MONITORING
Definition
Cerebral blood flow (CBF) monitoring is estimated blood flow in neurologically compromised client’s by calculating cerebral perfusion pressure. A sensor placed on the cerebral cortex calculates CBF in the capillary bed by thermal diffusion. Thermistors within the sensor detect the temperature differential between two metallic plates-orie heated one neutral (Fig. 29.80).
Indications
- Cerebral blood flow monitoring reveals the effects of interventions on it
- This monitoring technique yields important information about the effects of intervention on CBF which are essential in conditions in which compromised blood flow may put the client at risk, such as ischemia and infarction
- CBF monitoring is indicated whenever CBF alterations are anticipated.
- It is used most commonly in clients with subarachnoid hemorrhage, trauma associated with high intracranial pressure or vascular tumors.
Client and Environment Preparation
- Instruct the client and family members fully about the procedures involved in CBF monitoring
- Obtain informed content
- Instruct the client that the insertion site will be covered with a dry, sterile dressing.
Special Considerations
- CBF fluctuates with the brain’s metabolic demands, ranging from 60 to 90 mL/100 g/minute normally. However, the client’s neurological condition dictates the acceptable range For instance, in a patient in a coma, CBF may be half the normal value; in a client in a barbiturate-induced coma with burst suppression on the EEG, CBF may be as 101 mL/100 g/minute
- Vasospasm secondary to subarachnoid hemorrhage result in CBF below 40 mL/100 g/minute In an awake client, CBF above 90 mL/100 g/minute
- If you suspect poor contact between the sensor and the cerebral cortex, turn the client toward the side of the sensor or gently wiggle the catheter back and forth (using a sterile-gloved hand) If your client has low CBF but no neurological symptoms that indicate ischemia, suspect a fluid layer (a small hematoma) between the sensor and the cortex
- As with intracranial pressure monitoring, CBF monitoring may lead to infection. Administration prophylactic antibiotics as ordered and maintain in sterile dressing around the insertion site
- CSF leakage, another potential complication, may occur at the sensor insertion site. To prevent leakage, the surgeon usually places an additional suture at the site.
- Clean the site, starting at the center and working outwant in a circular pattern Using new gatize pad soaked with povidone lod solution, clean the exposed part of the sensor from insertion site to the sensor
- Apply povidone-iodine ointment to the insertion your faculty’s policy permits Place sterile 4774″ gauze over the insertion site completely cover it, tape all edges securely to cre occlusive dressing.
Removing the Sensor
- In most cases, the CBF sensor remains in place for about 3 days when used postoperative monitoring Explain the procedure to the client: then wash hands
- Put on clean gloves, remove the dressing and dispose the gloving and dressing properly.
- Open the suture removal tray and the package of suture material.
- The surgeon removes the anchoring sutures and then gently removes the sensor from the insertion site .
- After the surgeon closes the wound with stitches, put on sterile gloves, apply a folded gauze pad to the site and tape it in place Observe the condition of the site, including any leakage
After Care
- Observe the neurological vital signs at regular intervals
- Check the insertion site at regular intervals
- Documentation.
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