Point-of-Care Sonography in Women’s Health Care: Indications and Guidelines
Point-of-Care Sonography in Women’s Health Care: Indications and Guidelines
During the past decade, the use of sonography has become an integral tool in all aspects of health care, including emergency medicine, orthopedics, anesthesiology, critical care, urology, and trauma. Due to its diagnostic value in maternal/fetal assessment in pregnancy, as well as all aspects of women’s health care, it has become an essential device for most women’s health practices. Because of the ultrasound machine’s portability and ease of operation, sonography is available in all areas of the hospital, in clinics, and in private offices, as well as in remote areas such as military battle sites or rural communities. Sonography is now being offered as first-line “ultrasound first” assessment in the diagnosis and treatment of many health care issues.1 And because sonography has become such an integral part of health care, it is now being taught in many medical schools throughout the country beginning with the first year’s curriculum.2 As a result, the implementation of sonographic assessment has become a critical skill not only for specialized physicians, but also for all health care providers including nurses, midwives, advanced nurse practitioners (APN), and physician assistants (PA).
Specific to women’s health care and pregnancy, sonography is the imaging modality of choice for the evaluation of many signs and symptoms, such as determining the cause of vaginal bleeding in all trimesters, locating intrauterine devices, assessing for residual urine in the postpartum woman, and evaluating the endometrium in peri- and postmenopausal women. In many hospitals, labor room nurses are expected to have the minimum sonographic skills necessary to determine fetal presentation during labor when a physician or midwife is unavailable.
The majority of sonographic exams performed by nonsonographers are performed during a specific encounter in which the information obtained by ultrasound will immediately benefit the patient, thus avoiding delay in treatment. This type of assessmentspecific ultrasound has been termed “point-of-care” (POC) and described by the American Institute of Ultrasound in Medicine in 20103 as ultrasound use during a specific encounter or procedure to:
Enhance patient care,
Diagnose critical conditions,
Provide immediate care, and
Improve safety and effectiveness of invasive procedures.
Thus, POC ultrasound may be practiced in a variety of settings and utilized by a diverse set of health care providers. For the purposes of this book, the phrase “point-of-care” sonogram will be used according to this definition but will also encompass those ultrasound examinations previously referred to as “limited ultrasound.”
The increasing use of ultrasound by health care professionals other than sonologists (physician sonographers), sonographers, perinatologists, or radiologists has justifiably generated concern by professional organizations. Improperly trained personnel using sonography may lead to increases in the incidence of misdiagnoses and medical errors. For example, there have been both official and unofficial reported cases of clinicians performing sonograms for fetal presentation during labor and missing the presence of a second twin, the absence of cardiac activity, or a placenta previa. In part to establish minimal educational criteria, several professional organizations, such as the American Congress of Obstetrics and Gynecologists (ACOG), the American College of Nurse Midwives (ACNM), and the Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN) have published guidelines or position statements for the education and training of their members who wish to incorporate sonography into clinical practice.4, 5 and 6
Additionally, before incorporating sonography into clinical practice, it is important to investigate the individual state’s Nurse Practice Act or appropriate state laws to determine the feasibility of adding sonography to current practice. Once this has been achieved, hospital policies and procedures may be developed to address the minimal educational content, methods for measuring clinical competency, and risk management concerns pertaining to the implementation of sonography into clinical practice.
Box 8-1 Indications for Ultrasound During Pregnancy7-9
1st Trimester
2nd and 3rd Trimester
Confirm the presence of intrauterine pregnancy
Evaluate pelvic pain
Evaluate for suspected ectopic pregnancy
Determine source of vaginal bleeding in pregnancy
Estimate gestational age
Diagnose or evaluate multiple gestations
Confirm cardiac activity
Provide guidance for chorionic villus sampling, embryo transfer, or localization and removal of intrauterine device
Assess for certain fetal anomalies
Evaluate maternal pelvic or adnexal masses or uterine abnormalities
Screen for fetal aneuploidy
Evaluate suspected hydatidiform mole
Evaluate gestational age
Evaluate fetal condition in late registrants for prenatal care
Evaluate fetal growth
Evaluate vaginal bleeding
Evaluate cervical insufficiency
Evaluate abdominal and pelvic pain
Determine presenting part
Evaluate for suspected multiple gestation
Assess need for adjunct to amniocentesis and external cephalic version
Evaluate amniotic fluid abnormalities, suspected placental abruption or previa
Evaluate for premature ROM or labor
Evaluate for abnormal biochemical markers, follow-up of fetal anomaly, or history of prior congenital anomaly, screen for anomalies and findings that may increase the risk of aneuploidy
Adapted from U. S. Department of Health and Human Services, Diagnostic ultrasound in pregnancy, NIH Publication No. 84-667, 1984; American College of Radiology (ACR), Practice guidelines for the performance of obstetrical ultrasound, 2007:1025-1033; and American College of Obstetricians and Gynecologists (ACOG), Ultrasonography in pregnancy, Practice bulletin #101, 2009.
The purpose of this chapter is to describe the various sonography practice guidelines pertinent to pregnancy and women’s health care. The guidelines begin with the indications for sonographic exams, along with the details of the “standard” exams performed by a sonographer or radiologist. This is followed by guidelines for the application of specific components of the standard sonogram that may be used during a POC assessment and performed by a nonsonographer.
INDICATIONS FOR DIAGNOSTIC ULTRASOUND IN OBSTETRICS
In 1984, the National Institutes of Health7 formed a committee of obstetric and sonography experts to generate a list of indications for ultrasonography during pregnancy. These indications were updated by the American College of Radiology (ACR)8 and the American College of Obstetrics and Gynecology (ACOG),4 as shown in Box 8-1. Based on these guidelines, it should be noted that routine sonography for every pregnant woman is not an indication in itself.
PROFESSIONAL ORGANIZATION GUIDELINES
Traditionally, the vast majority of obstetric and gynecologic sonograms have been performed by sonographers, radiologists, and other physicians with specialized training in ultrasound. Professional organizations, such as the ACR and the American Institute of Ultrasound in Medicine (AIUM), published guidelines that set general recommendations for what should be included for each type of complete sonogram.
The American Institute of Ultrasound in Medicine
The AIUM is a multidisciplinary professional organization whose membership includes physicians, sonographers, and others from all medical specialties involved in sonography. Their primary goal is to promote the safe and effective use of ultrasound through education, research, and guideline publications; as well as through the accreditation of facilities where ultrasound is performed. The AIUM also works in conjunction with other medical and nursing specialties to develop joint clinical guidelines that pertain to a specific type of practice. The AIUM Guideline for the Performance of Obstetric Ultrasound Examinations, written in conjunction with ACOG, is an example of this collaborative work.
AIUM Practice Guideline for the Performance of Obstetric Ultrasound Examinations
In 2007, the AIUM revised its obstetric guidelines in conjunction and collaboration with ACOG and the ACR. Personnel requirements and other aspects specific to the area of specialization (i.e., obstetrician vs. radiologist) are addressed by the individual professional organization. Additionally, this document stresses that fetal ultrasound should only be performed in response to a valid medical indication while utilizing the lowest possible exposure settings.
One of the major changes in this document from prior publications was the recategorization of the various types of sonograms, terms that were then adopted by other professional organizations. The new sonographic classifications include (1) the standard first-trimester ultrasound examination, (2) standard second/third trimester examinations (formerly referred to as the basic scan), (3) limited examination, and (4) specialized examinations (formerly referred to as the comprehensive or targeted scan).9 Because ACOG not only coauthored this guideline but also adopted this classification system for its own 2009 guideline, the details for each classification are described later, along with other content from the ACOG obstetric guideline.4
The AIUM guideline also provides information pertaining to the anatomic landmarks needed for each specific fetal measurement and stands as an excellent document to use during the clinical practicum. Members of AIUM have access to an online enhanced version of this guideline that shows images of each anatomic landmark with proper cursor placement.9
AIUM Practice Guideline for the Performance of the Ultrasound Examination of the Female Pelvis
As with obstetric ultrasound, AIUM recommends that scanning of the female pelvis should only be performed when there is an indication or a valid medical reason for the procedure. These indications may include pelvic pain, menstrual disorders, postmenopausal bleeding, abnormal pelvic examination, localization of an intrauterine device, and evaluation and monitoring of infertility treatments. Please refer to the guideline for a complete list of indications, as well as a description of the specific landmarks for measurement and evaluation.10 Further description of the sonographic evaluation of the female pelvis is detailed in Chapter 10.
AIUM Practice Guideline for the Performance of Ultrasonography in Reproductive Medicine
Ultrasound is an integral part of the evaluation and treatment of women with infertility issues. Whenever possible, AIUM recommends that a transvaginal approach be used for the evaluation of each organ and anatomic structure in the female pelvis. A comprehensive examination should first be performed to rule out pelvic pathology. If all necessary images cannot be obtained with the transvaginal approach, then the transabdominal scan should be done. Also, if there is any question of a pelvic mass, a transabdominal transducer can be used.
Under certain circumstances, a limited pelvic ultrasound may be performed based on a specific indication. Examples of a limited pelvic ultrasound include a folliculogram, which is used to monitor ovarian stimulation; and other procedures in reproductive medicine, such as an ultrasound-guided follicular puncture for egg retrieval with in-vitro fertilization and embryo transfer.11
This document also delineates recommendations as to appropriate documentation. For example, when a limited folliculogram is performed, documentation should include (1) the number of ovarian follicles in each ovary and (2) endometrial thickness and endometrial morphologic appearance.11
American Society for Reproductive Medicine
The American Society for Reproductive Medicine (ASRM) also provides guidelines for registered nurses (RNs) who have had specific training and supervision to perform ultrasound examinations in gynecologic and reproductive medicine. These guidelines do not stand alone; they are intended to be used in conjunction with other nursing guidelines, state laws, and institutional policy that address nursing practice in these areas of nursing. A limited ultrasound examination in gynecology and reproductive medicine performed by nurses would include determining the number and size of developing follicles and the measurement of endometrial thickness and appearance.11,12
The American College of Obstetricians and Gynecologists
In 2009, ACOG, in conjunction with AIUM, published a technical and educational bulletin pertinent to sonography performed by obstetricians and gynecologists.4 This publication updated all components and parameters for the obstetric ultrasound examination and included the three categories of ultrasound examinations established by AIUM in 20079: (1) the limited examination, (2) the standard examination in all trimesters, and (3) the specialized examination.
A limited ultrasound is a less extensive examination that may be dictated by the clinical situation requiring investigation. Indications may include assessment of amniotic fluid, presence or absence of cardiac activity, confirmation of the fetal presenting part, interval growth, evaluation of the cervix, and placenta localization. Limited sonography may be performed by sonographers or specially trained personnel. A limited examination does not replace a standard examination.
A standard ultrasound examination (formerly referred to as “basic,” “complete,” “formal,” or “level-one ultrasound”) generally is performed by sonographers or sonologists in the radiology or ultrasound department as a prescheduled, planned evaluation during all trimesters of pregnancy. The first-trimester standard sonogram may be performed by either the transabdominal or transvaginal approach. If a transabdominal examination is not definitive, a transvaginal or transperineal scan should be performed. Although this differs from the AIUM guideline, the intent is the same: if all parameters cannot be visualized with one approach, then the alternate approach should be utilized. Per ACOG, the parameters for a first-trimester ultrasound examination include:
Evaluation of the uterus, cervix, and adnexa for the presence of a gestational sac
Documentation of the presence, size, and location of uterine and adnexal masses (such as leiomyomas)
Assessment of the anterior and posterior cul-desac for presence or absence of fluid
Localization of the sac
Assessment for presence or absence of cardiac activity
Assessment of fetal number
Assessment for presence of a sac but the absence of a definite embryo or yolk sac (which may indicate a pseudogestational sac that may be consistent with an ectopic pregnancy; transvaginally, an embryo should be visible with a mean gestational sac diameter greater than or equal to 20 mm)
Assessment of fetal anatomy according to gestational age
Measurement of nuchal translucency at a specific gestational age and in conjunction with serum biochemistry in patients requesting individual risk assessment for aneuploidy
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