Comparison of Image-Guided Nonfocal Hepatic Biopsies Performed by Physicians and Nurse Midlevel Providers

Image-guided hepatic biopsies have been performed safely and accurately for a number of years. The advantages of sonographic or CT guidance in avoiding major vital structures, such as large vessels, the gallbladder, or pleura, have been confirmed many times. However, the safety and accuracy of certified nurse practitioners’ performing these biopsies have not been described. The authors describe a retrospective review of 418 image-guided hepatic biopsies that demonstrated no significant difference in accuracy or complication rates between biopsies performed by certified nurse practitioners and those performed by radiologists in a single-institution, multihospital academic setting. Appropriately trained advanced practice providers can perform image-guided hepatic biopsies safely and accurately.

Introduction

The use of percutaneous nonfocal liver biopsy to stage liver disease and response to medical management of nononcologic liver disease is a well-established medical procedure 1, 2. Although percutaneous hepatic biopsies can be performed blindly at the bedside using palpation or percussion techniques, the addition of cross-sectional imaging allows precise needle localization, avoiding major vessels and anatomic structures [3]. Most medical centers are now using imaging guidance, either CT or ultrasound, for their nonfocal hepatic biopsies. In addition to selecting a safe site to avoid critical structures, imaging guidance provides exact depths from the skin surface to the liver capsule and calculates the correct depth for needle-tip placement. This helps reduce the risk for postprocedural bleeding by demonstrating the needle depth needed to provide several centimeters of overlying liver parenchyma.

Furthermore, percutaneous sampling using image guidance in an outpatient population is safe and cost effective 4, 5, 6. At our institution, we routinely perform nonfocal hepatic biopsies using ultrasound guidance or, less commonly, CT. Hepatic biopsies are performed by trained radiologists, residents, or fellows under attending physician supervision, or by nurse practitioners (NP).

The NP role, which developed in the 1960s, has been shown, for example, to provide safe primary care to stable patients with chronic disease compared with physician services 7, 8, 9. With the increasing complexity of patients in today’s health care system, and the United States on the verge of a physician shortage estimated to be at 130,000 by 2025 [10], coupled with the push to save health care dollars, the use of nonphysician advanced practice providers such as NPs and physician assistants is on the rise [11]. Continued evaluation of the role of these advanced practice providers is essential to determine the value and safety of their care.

Currently, NP training includes a baccalaureate degree in nursing, licensure as a registered nurse, and graduation from an accredited master’s degree program [12]. NPs are then eligible to take a national certification examination to become board certified in their practice areas. Board certification is offered by various nursing organizations, such as the American Nurses Credentialing Center or the American Academy of Nurse Practitioners. Board certification ensures entry-level competency and is a practice requirement for NPs in most states. NPs who seek to practice in hospitals undergo additional credentialing review similar to that of physicians and must be granted the privilege to practice in the hospitals through the authority given to their medical staffs by the boards of directors [13]. There is considerable variability in NPs’ scope of practice among states, with nursing boards governing practice in each state. A credentialing hospital can further restrict NPs’ scope of practice but cannot expand the scope beyond what is permissible by state law [14].

At our academic institution, NPs receive specialized training in image-guided biopsies under the supervision of attending radiologists. They then perform a minimum of 10 nonfocal hepatic biopsies under the direct supervision of an attending physician, after which they obtain hospital credentialing for independent performance of interventional procedures. During annual performance evaluation, a random sample of procedures performed throughout the year is evaluated for quality and outcome measures. Outcome measures include diagnostic yield, patient complication rate, and documentation quality.

The primary purpose of this retrospective study was to compare the safety and diagnostic accuracy (yield) of nonfocal hepatic biopsies performed by physicians and NPs. A secondary goal was the evaluation of differences in pain level or the use of pain medications in cases performed by these two groups of practitioners.