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Information ⬇

Synonym/Acronym

RFA, RF ablation, MWA, rhizotomy.

Rationale

To assist in treating tumors of the liver that are too small for surgery or have poor response to chemotherapy.

Patient Preparation

There are no activity restrictions unless by medical direction. Instruct the patient to fast and restrict fluids for 8 hr, or as ordered based on the type of anesthesia to be used, prior to the procedure. Fasting may be ordered as a precaution against aspiration related to possible nausea and vomiting. The American Society of Anesthesiologists has fasting guidelines for risk levels according to patient status. More information can be located at www.asahq.org.

Normal Findings

  • Decrease in tumor size
  • Normal size, position, contour, and texture of the liver.

Critical Findings and Potential Interventions ⬆ ⬇

N/A

Overview ⬆ ⬇

Study type: X-ray Special/Contrast; related body system: Digestive system.

Radiofrequency ablation (RFA) and microwave ablation (MWA) are minimally invasive therapies used to eliminate tumors in organs such as the liver. The two most common types of liver cancer treated with ablation techniques are primary hepatocellular carcinoma and colon cancer that has metastasized to the liver. Ablation is successfully used to treat cancer in other parts of the body such as the adrenal glands, bone, breast, kidney, lung, pancreas, and thyroid, and to remove fibroids in the uterus. The approach is used in destroying tumors that may have failed to respond to chemotherapy or have recurred after initial surgery. If there are multiple tumor nodules, they may be treated in one or more sessions. Cardiac ablation is used to remove scar tissue in the heart and restore normal heart rhythm. In general, ablation causes only minimal discomfort and may be done as an outpatient procedure without general anesthesia. The procedure can be performed percutaneously, laproscopically, or by open surgery.

The RFA technique works by passing electrical current in the range of radiofrequency waves between the needle electrode and the grounding pads placed on the patient’s skin; in MWA, microwaves are created from the needle. The needle electrode is placed in the tumor under the guidance of an imaging method such as ultrasound (US), computed tomography (CT) scanning (with or without iodinated contrast), or magnetic resonance imaging (MRI). US is a commonly used imaging technique. A radiofrequency current or microwaves are then passed through the electrode to heat the tumor tissue near the needle tip and to ablate, or eliminate, it. The current creates heat around the electrode inside the tumor, and this heat spreads out to destroy the entire tumor but little of the surrounding normal liver tissue. The heat also closes up small blood vessels, thereby minimizing the risk of bleeding. Because healthy tissue withstands more heat than a tumor, these ablation techniques are able to destroy a tumor and a small rim of normal tissue about its edges without affecting most of the normal organ. The dead tumor cells are gradually replaced by scar tissue that shrinks over time. Ablation techniques are most effective if the tumor is less than 4 cm in diameter; results are not as good when RFA is used to treat larger tumors.

Indications ⬆ ⬇

Interfering Factors ⬆ ⬇

Contraindications

Pregnancy is a general contraindication to procedures involving radiation.

Patients with the presence of large or numerous tumors (studies show that RFA is most successful if fewer than three tumors are present and each lesion is not greater than 3 cm in size; ablation of tumors that occupy greater than 40% of the liver may not leave sufficient liver capacity to support normal function).

Patients with metastasis to the bile duct or surrounding hepatic vessel.

Patients with bile duct or major vessel invasion.

Patients with significant extrahepatic disease.

Potential Medical Diagnosis: Clinical Significance of Results ⬆ ⬇

Abnormal Findings Related to

N/A

This is a therapeutic procedure.

Nursing Implications, Nursing Process, Clinical Judgement ⬆

Before the Study: Planning and Implementation

Teaching the Patient What to Expect

  • Discuss how this procedure can assist in removal of some types of liver tumors.
  • Explain that each ablation takes about 15 to 30 min; multiple ablations may be performed requiring additional time. The procedure is usually performed in an interventional radiology department.
  • Review the procedure with the patient.
  • Explain that pregnancy testing may be required.
  • Explain that prior to the procedure, laboratory testing may be required to determine the possibility of bleeding risk (coagulation testing) or to assess for impaired kidney function (creatinine level and estimated glomerular filtration rate) if use of iodinated contrast medium is anticipated.
  • Discuss how there may be moments of discomfort or pain when the IV line is inserted, allowing for infusion of fluids such as saline, anesthetics, sedatives, medications used in the procedure, or emergency medications.
  • Explain that a sedative, local anesthetic, and/or analgesia will be administered to promote relaxation and reduce discomfort prior to the needle electrode insertion.

Procedural Information

  • Baseline vital signs are recorded and monitored throughout the procedure.
  • Positioning for this procedure is in the supine position on an examination table.
  • Electrocardiographic electrodes are placed on the patient for cardiac monitoring.
  • Baseline ECG rhythm is established, and any ventricular dysrhythmias are identified.
  • The selected area is cleansed and covered with a sterile drape.
  • A local anesthetic is injected at the site and a needle electrode inserted under US, CT, or MRI guidance.
  • Contrast may be used to aid in CT guidance for placement of the ablation needle electrodes.
  • A radiofrequency current is passed through the needle electrode, and the tumor is ablated.
  • The patient is reminded to take slow, deep breaths during the procedure to decrease nausea. An ordered antiemetic drug is administered as needed, and an emesis basin is ready for use.
  • Once the study is completed, the needle or catheter is removed, and a pressure dressing is applied over the puncture site.

Potential Nursing Actions

Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.

Safety Considerations

  • Anticoagulants, aspirin, and other salicylates should be discontinued by medical direction for the appropriate number of days prior to a procedure where bleeding is a potential complication.

After the Study: Implementation & Evaluation Potential Nursing Actions

Avoiding Complications

  • Monitor the patient for complications related to the procedure.
  • Establishing an IV site and injection of contrast medium are invasive procedures that can cause rare complications. For additional information, see Appendix A: Patient Preparation and Specimen Collection, subsection: Potential Contraindications and Complications Associated With Diagnostic Procedures.
  • Discuss the importance of immediately reporting symptoms such as difficulty breathing, chest pain, fever, hyperpnea, hypertension, nausea, palpitations, pruritus, rash, tachycardia, urticaria, or vomiting.
  • Administer ordered antihistamines or prophylactic steroids if the patient has an allergic reaction.
  • Observe/assess the needle insertion site for bleeding, inflammation, or hematoma formation.
  • Complications related to the ablation are rare but may include postablation syndrome, brief or long-lasting shoulder pain, hepatic abscess, biloma, inflammation of the gallbladder, damage to the bile ducts with resulting biliary obstruction, thermal damage to the bowel, thermal damage to surrounding tissue resulting in cellulitis, hemorrhage, or flu-like symptoms that appear 3 to 5 days after the procedure and last for approximately 5 days.

Treatment Considerations

  • Follow postprocedure vital sign and assessment protocol.
  • Resume the usual diet, fluids, medications, or activity, as directed by the health-care provider.
  • Instruct the patient to maintain bedrest for 4 to 6 hr after the procedure or as ordered.
  • Instruct the patient in the care and assessment of the site.

Clinical Judgement

  • Consider how to best approach discussing end-of-life options with a terminal diagnosis.

Follow-Up and Desired Outcomes

  • Understands the implications of unfavorable outcomes on lifestyle choices as well as the need for postprocedural follow-up imaging.