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Liver Biopsy: how it is performed
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Marcelo Kugelmas, M.D.
Division of Gastroenterology, Hepatology Section University of Colorado, Health Sciences Center, Denver, CO
American Journal of Gastroenterology
Volume 99 Issue 8- August 2004
TO THE EDITOR: Regardless of how well prepared for a liver biopsy, patients are anxious and scared on the day of the procedure.
Our initial challenge is to ease the patient's tension prior to the liver biopsy. We also need to review the indication for the biopsy, whatever test results are available since the patient's last visit, and explain the procedure and its risks, while reassuring the patient.
PREPROCEDURE STEPS: INFORM AND HELP THE PATIENT RELAX
I usually arrive at the bedside after the endoscopy nurse has admitted the patient, taken a history, found the patient fit for the liver biopsy, and started a peripheral IV line. The most common indications for liver biopsy are to stage chronic liver disease, mostly chronic hepatitis C; to aid in the diagnosis of elevated liver tests, usually ruling out nonalcoholic fatty liver disease and nonalcoholic steatohepatitis; within the context of a clinical trial; or to evaluate elevated liver tests in a liver transplant recipient. I usually inform the patient why I am doing the liver biopsy, what information I expect to obtain from it, and when the results are going to be available. Sharing information with the patient eases their participation.
I then review the results of the blood tests.
SCREENING TESTS
We require, in our unit, complete blood count and prothrombin time obtained within the last 2 wk. For pretransplant patients who do not have advanced liver disease, older blood tests are acceptable if done within the preceding 3 months. In liver transplant recipients, liver tests and serum creatinine are usually available. Women of childbearing age are screened for pregnancy. Safety guidelines for acceptable values for biochemistry exist for performing a liver biopsy. We usually accept patients who have platelet counts above 60,000 per mm3 and INR <1.6. For those with renal insufficiency (serum creatinine greater than 1.5 mg/dl) I usually administer DDAVP (desmopressin) 0.3 mcg/kg IV over 15-30 min prior to the procedure.
The last step before setting up for the biopsy is to obtain informed consent and review the technique and the potential risks of the procedure.
CONSCIOUS SEDATION AND BETTER ACCEPTANCE
After informed consent has been obtained, it is a good time to give conscious sedation. Sedation is an option but most of our patients choose to receive it. The test's acceptance is better, and it is my subjective impression that the patient feels that the team is doing "more" when we offer this option. Premedication, even in small doses, may be given to all except those who must drive because no alternative transportation is provided or those who have a history of intolerance or allergy to the agents we use. We usually give 50 mcg of fentanyl and 1 mg of midazolam by IV push, and, on rare occasions, we may repeat the dose once. The goal of conscious sedation is to have a relaxed but cooperative patient who is likely to return in the future if another liver biopsy is indicated.
Note from Jules Levin: some doctors may consider stronger sedation for former users.
BEDSIDE ULTRASONOGRAPHY IS OPTIONAL AND MAY BE USEFUL
Now, with a more relaxed patient, I proceed with setting up for the actual biopsy. I perform a physical exam, with particular attention to the right thorax and right upper quadrant. I inspect, palpate, and percuss until I determine which intercostal space I will be using for the procedure. Confirmation using bedside ultrasonography follows. The ultrasound is not absolutely necessary, but on a rare occasion, it has helped me prevent aiming in the direction of the gallbladder or a hepatic hemangioma. Other times, the bedside ultrasound has helped me determine that the anatomical window to perform the biopsy was too narrow, and that a radiologically guided approach would be safer, usually in patients with advanced liver disease, right hepatic lobe hypoplasia, or colonic interposition. The ultrasound also helps me see the anatomical window as the patient inhales and exhales. It is not uncommon when using bedside ultrasonography that I find the best timing for the biopsy is not the traditional end of expiration, but rather at some point of the inspiratory effort. Finally, bedside ultrasonography makes the left lobe accessible through the anterior abdominal wall.
DON'T GET CREATIVE: FOLLOW YOUR OWN ROUTINE
Setting up the field is no different than for any other sterile procedure. A sterile field is placed under the patient's right side, the intercostal space is then prepped with iodine solution, and another field is placed over the patient's skin. Then the iodine solution is wiped with sterile 4 x 4 gauze. Local anesthesia is given first to the skin and then to the parietal peritoneum using 1% lidocaine. The skin is injected with a 25 gauge needle with approximately 1 cc of lidocaine, and aiming at making a classic "peau d'orange." The parietal peritoneum is injected with a 1.5 inch long, 21 gauge needle. This needle also helps to "probe" for the liver: just pass the parietal peritoneum with it, and ask the patient to take a breath, many times you'll "feel" and sometimes "hear" the needle scratching the liver surface (if one chooses to do this, the syringe must be held very loosely, as the inspiratory effort will displace the ribs, liver, and soft tissues caudally). Once the area is anesthetized, it is time to cut the skin using a scalpel in order to allow for the biopsy needle to go through. Probably the best piece of advice for this part of the procedure is not to bury the scalpel. Just cut the skin, what lies beneath is soft tissue easily traversed by the liver biopsy needle. A deeper cut may cause excess local bleeding.
IN ORDER TO GET ENOUGH INFORMATION YOU MUST PROVIDE THE PATHOLOGIST WITH AN ADEQUATE SAMPLE
Current literature suggests that cutting needles are less likely to have problems with liver core fragmentation, in particular when dealing with a cirrhotic liver sample. Liver biopsies are prone to sampling error, and it is therefore crucial to provide the pathologist with an adequate sample, containing at least 10 portal triads, usually longer than 1.5 cm. A recent publication suggests that samples should be at least 2.5 cm in length, but that may require three passes into the liver, increasing the risk of postprocedure bleeding complications.
Just before obtaining the sample, I have the patient rehearse the breathing motion one more time. Then, always using a sterile technique, I introduce the needle on top of the inferior rib (in order to prevent accidental injury to the interscostal vascular package) and all the way to the peritoneum. Now I ask the patient to breathe as we had practiced before, and while he/she is holding their breath, I advance the needle into the liver and activate the cutting mechanism. In order to obtain an adequate sample a second pass into the liver is usually in order, but a third pass is rarely needed and it increases the chances of bleeding complications.
The biopsy itself takes just a few seconds. It is now time to clean up, put an adhesive bandage over the skin incision and have the patient recover. I usually have the patient remain in the right lateral decubitus position for 2 h and on the back for another 2 h for a total of 4 h of observation. The observation period includes frequent vital signs checks: every 15 min the first hour, every 30 min the second hour, and hourly thereafter. If the patient experiences pain, I usually prescribe either 1 g of acetaminophen or 5 or 10 mg of oxycodone.
WRAP-UP
I see the patient before discharge. A family member or another companion is usually present. It is a good time to reassure them and provide them with a telephone number to call in case of problems. I also review the probable timing of the biopsy report, and we agree to either discuss the results over the phone or at the time of a follow-up clinic appointment. Lastly, I remind the patient not to use aspirin or aspirin-like products for 10 days.
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