Liability in ob/gyn ultrasound

Ultrasound has revolutionized the care of women with obstetrical and gynecologic disorders. It offers critical diagnostic information in a cost-effective, efficient manner, with availability in virtually every ob/gyn office in the country. It has assumed the position as the first-line approach to evaluating pregnancies, as well as many common gynecologic disorders.¹ However, the quality of the equipment, personnel training, and even the education and experience of the interpreting physician is quite variable. Thus, study quality is not universally excellent. As a result, errors in diagnosis and interpretation can occur. This article addresses common errors that lead to litigation involving ob/gyn ultrasound, with options to reduce ultrasound-related litigation.  

Malpractice: A definition

Malpractice is a tort that requires proof of 4 basic elements: 1) the provider had a duty to care for the patient; 2) a breach of that duty occurred, i.e. a breach of the standard of care; 3) harm directly resulted from that breach; and 4) the harm produced compensable damages. In a liability action, failure to prove every element causes the action to fail. Medical litigation is a civil action. Thus, the burden of proof required to prove each element is the preponderance of the evidence (something > 50%), e.g. more probable than not, which is less stringent than criminal litigation, which is beyond a reasonable doubt.  Litigation related to ultrasound focuses on inadequate image acquisition, errors in interpretation or reporting, and lack of obtaining an imaging study.

Inadequate image acquisition

Litigation in this area encompasses all aspects of obtaining suitable images. This includes: 1) inadequate training of the sonographer or sonologist performing the ultrasound study; 2) an inadequate or incomplete study, with images lacking sufficient quality to make an appropriate diagnosis; 3) inadequate supervision of the sonographer; and 4) inadequate maintenance of imaging equipment. Standards have been established for the performance of quality ultrasound studies. Such standards must be met for a practice to achieve accreditation. Such accreditation establishes compliance with accepted “best practices” and may enhance defensibility in the event of a lawsuit.²

Training of personnel performing ultrasound examinations

Sonographers undergo extensive training, testing, and certification to learn proper study performance and image acquisition. The Joint Commission requires that all sonographers employed in a hospital-based environment be certified or eligible for certification by an organization accredited by the National Commission of Certifying Agencies or the American National Standards Institute – International Organization for Standardization. Accredited organizations include the American Registry for Diagnostic Medical Sonography (Registered Diagnostic Medical Sonographer) and the American Registry of Radiologic Technologists. Although learning ultrasound on the job with no formal certification was common in the past, the practice has essentially been replaced by formal, more rigorous training.³

Inadequate or incomplete studies

Ultrasound studies should include adequate images to allow appropriate diagnosis. Incomplete studies increase liability, particularly in the case of missed diagnoses. Studies should conform to guidelines of national organizations such as the American Institute of Ultrasound in Medicine (AIUM)and the American College of Obstetricians and Gynecologists (ACOG),^4,5 as to the required images for each type of obstetrical or gynecologic study, appropriate measuring criteria, and documentation standards. Following such guidelines enhances the quality of ultrasound studies and helps mitigate liability. For instance, the standard obstetric ultrasound examination includes a complete anatomic survey, including evaluation of the cardiac outflow tracts. Performing a limited ultrasound, such as for dating purposes, does not meet the required elements of a complete obstetrical ultrasound. In such circumstances, a complete anatomic survey, included in the standard obstetric ultrasound, should be performed at the next available opportunity during the pregnancy.  If findings during antepartum screening or ultrasound warrant further evaluation, the patient should be referred for a specialized examination, the “detailed” or “targeted” ultrasound.⁴ Performing an incomplete study increases the chance of missing significant fetal abnormalities and the risk of incurring significant liability.

Exceptions for limited or focused examinations

In 2009, AIUM and the American Society for Reproductive Medicine published a consensus statement that ultrasounds performed for follicular monitoring were within the scope of practice of a nurse with specific training in ultrasound and with appropriate physician supervision in an infertility practice.⁶ The consensus included a statement that a comprehensive ultrasound examination should have been performed within the prior 4 to 6 months to exclude significant gynecologic abnormalities.

Supervision requirements

There are 3 levels of supervision for imaging studies: general, direct, and personal supervision. With general supervision, the physician’s presence is not required during the performance of the procedure. However, the training of the non-physician personnel who perform the diagnostic procedure and equipment maintenance are the responsibility of the physician. With direct supervision, the physician must be present in the office suite and immediately available to furnish assistance and direction throughout the performance of the procedure. However, the physician’s in-room presence is not required during the performance of the procedure. Personal supervision requires that the physician must be personally present in the room during the performance of the procedure. In ob/gyn ultrasound, general supervision is the standard, with the exception of percutaneous umbilical blood sampling, chorionic villus sampling (, amniocentesis, and sonohysterography/sonosalpingography, which require personal supervision.⁷ Inadequate supervision exposes physicians to greater liability risks and, potentially, claims of fraudulent billing.

Inadequate equipment maintenance

The quality of ultrasound equipment has improved exponentially. High-quality equipment is now within the budget of virtually any medical practice. As such, the expectation is that a practice will use contemporary equipment that has been properly maintained. Using equipment that is no longer supported by the manufacturer, generally due to the age of the equipment, implies that the practice is providing substandard care. Further, not performing proper preventive maintenance may result in poor image quality, increasing the liability risk for physicians and their practices. This author has witnessed cases turning on poor image quality from dated, or poorly maintained, ultrasound equipment.

Errors leading to litigation

Several types of errors are commonly found in liability claims against physicians: perception errors, interpretation errors, failure to suggest the next appropriate procedure, and failure to communicate critical findings to the referring physician.⁸ Case examples will illustrate such errors.

Perception errors

A perception error occurs when an abnormality is seen in retrospect, but was missed when interpreting the original study. A common example is a fetal anomaly that is present on the imaging study, but was not identified by the interpreting physician. A typical claim is that of wrongful birth, when the patient claims she would have terminated the pregnancy if she had known of the abnormalities.^9,10 In such cases, experts establish whether it is below the standard of care for the physician not to have seen the abnormality.¹¹ Such errors are difficult to defend, and almost 80% of such cases are lost if they go to a jury award.¹¹As such, suits involving missed diagnoses are often settled to avoid the risk of massive awards at jury trial. Other examples include a malignant lesion not recognized on the initial ultrasound image. The resultant delay in diagnosis is alleged to increase the stage at diagnosis, reduce subsequent curability, worsen the patient’s prognosis, and, thus, shorten the patient’s life expectancy.

Interpretation errors

An interpretation error occurs when the abnormality is perceived but is incorrectly described. Two such instances include a malignant lesion called benign, or a normal variant called abnormal. An example of the former would be an ovarian mass, interpreted to be a dermoid but that is, in fact, a mucinous adenocarcinoma. An example of a normal variant called abnormal would be when a hemorrhagic corpus luteum is called a malignant lesion, resulting in extensive surgery that was unnecessary.

The best defense in these cases is an appropriate differential diagnosis, preferably including the correct diagnosis, with appropriate follow-up recommendations, including additional imaging or other diagnostic options, such as endometrial biopsy or obtaining tumor markers. When such recommendations are present, these cases are much more defensible, with almost 75% won when proceeding to trial.¹²

An increasingly frequent area of  litigation occurs when an intrauterine pregnancy is erroneously called an ectopic pregnancy, with subsequent treatment with methotrexate.¹³ Methotrexate is associated with an increased risk of pregnancy loss and, in the event of ongoing pregnancy, an increased risk of fetal anomalies.¹⁴ When the initial ultrasound fails to identify either an ectopic pregnancy or an intrauterine pregnancy, the classification should be pregnancy of unknown location (PUL).¹⁵ Recommended follow-up includes serial hCG levels and repeat ultrasound when appropriate. With abnormally rising hCG levels, an ectopic pregnancy can be suspected but not diagnosed.¹⁶ Caution should be exercised when diagnosing the absence of an intrauterine pregnancy with increasing hCG, given discriminatory levels. Current literature indicates that until the hCG level is above 2500 to 3500 mIU/mL, absence of an intrauterine gestational sac cannot be assured.^17,18 Additional caution is warranted in multiple gestations because an intrauterine gestational sac may not be seen with relatively high hCG levels. Some of the most significant judgments have occurred in such cases.

Failing to suggest the next appropriate procedure

A prudent sonologist will suggest the next appropriate study or procedure based upon current findings and clinical presentation. For example, in the event of a significant discrepancy between size and dates, adjustment of the due date should be recommended, with follow-up confirmation with future ultrasound studies. When ectopic pregnancy is suspected and the diagnostic findings are equivocal, interpreting sonologists often recommend serial hCG levels, with a repeat ultrasound, as clinically indicated. Similarly, when ultrasound is used to screen patients with postmenopausal bleeding, an endometrial thickness > 4 mm should prompt a recommendation for further evaluation including sonohysterography, hysteroscopy, or endometrial biopsy.¹⁹

Communication errors

Sonologists who perform or interpret ultrasounds on referral are obligated to communicate significant findings to their referring physicians. Although the final written report is considered the definitive means of communicating the results of an imaging study or procedure, direct or personal communication must occur in certain situations.²⁰For example, the finding of a significant fetal anomaly should be communicated directly to the referring physician and that communication should be documented in the final report. Failure to do so subjects the interpreting physician to a claim of wrongful birth, based on failure to communicate such findings in a timely and clinically appropriate manner.⁸ Another example is when a pregnancy due date should be changed. Cases exist in which liability was found when a patient is electively delivered prematurely, e.g. a repeat cesarean birth, and the recommendation for adjusting the due date was not clear in the final report, nor communicated to the referring physician.

Similar liability occurs when a patient is found to have an ectopic pregnancy, which is not communicated to the referring physician in a timely manner. Such delays can lead to emergency surgery, loss of a fallopian tube, or worse, even patient death.

Not performing an ultrasound

In obstetrical ultrasound, there are specific indications for performing a specialized “7681" ultrasound examination.²¹ Not recognizing these indications and not referring to patient for a more advanced study places the practitioner at greater liability risk, particularly if a potentially diagnosable condition or abnormality could have been detected. Thus, it is critical that a provIder identify specific risk factors and promptly refer a patient to reduce his or her liability risk.

In gynecology, failure to perform appropriate studies when patients are symptomatic exposes the physician to increased liability. For example, a menopausal patient with complaints of abdominal bloating and early satiety that occur > 13 times per month for < 1 year has symptoms concerning for ovarian cancer.²² In such cases, obtaining an ultrasound or referring the patient for one is critical. If the patient is subsequently diagnosed with ovarian cancer, failure to perform a timely ultrasound or imaging study would create significant liability risk. 

Determining the malignant potential of an adnexal mass and need for referral to a gynecologic oncologist is crucial in patient care. A recent international consensus panel recommended that, “it is appropriate to consider referral to an expert gynecologic sonologist when faced with a challenging or indeterminate adnexal mass.”²³ Failure to refer a patient for such studies would increase a physician’s risk exposure.

Reporting and image storage requirements

Specific guidelines for ultrasound reporting have been propagated by AIUM.²⁴ These guidelines establish the content and timing of an ultrasound report, and represent best practices in ultrasound use. Deviating from the guidelines could place an interpreting physician at risk, particularly if timely reporting of significant findings does not occur.

Best practices dictate that a formal report, with appropriate image documentation, occur with each examination. Although a note in the patient chart can meet the minimal requirement, a formal written report enhances the credibility of the performing lab or institution, and clarity for the referring physician. Images should be maintained for the applicable statute of limitations for each state or jurisdiction. Retaining images either in an archiving system (PACS system) or in digital format is preferable to thermal prints.

Informed consent

Informed consent involves comprehension, or understanding, and voluntary choice.²⁵ Two standards of consent-the reasonable person (patient) and the reasonable physician-vary with each jurisdiction. The reasonable patient standard holds that the communication to the patient is adequate and sufficient enough that a reasonable person could make a reasonable decision based on the provided information. The reasonable physician standard holds that the information communicated to the patient is what a reasonable physician would have discussed with the patient. Informed consent is an interactive discussion and understanding between the patient and physician and the signed consent merely memorializes those discussions.²⁵

The elements of ultrasound consent comprise: 1) a discussion of the diagnosis or nature of the condition; 2) the planned procedure; 3) alternatives to the procedure, including doing nothing; and 4) the substantial risks of the ultrasound or procedure. Further, a discussion of potential outcomes if an ultrasound is not done is inherent to adequate informed consent.²⁶ Requirements for written consent for specific ultrasound studies varies regionally, locally, and between institutions. However, a discussion of the limitations of any ultrasound study is integral to appropriate informed consent.

Obstetrical ultrasound poses several challenges: 1) the inherent inability to visualize all fetal abnormalities or anomalies; 2) the fact that some anomalies evolve during the course of a pregnancy; and 3) the challenges fetal position or maternal body habitus impose in adequately visualizing all required fetal anatomy. Informing the patient of these limitations and documenting such limitations is crucial to mitigating liability. It is advisable that a patient’s body mass index (BMI) be included in all ultrasound reports. This objectively addresses one of the major imaging limitations encountered with increasing frequency. In addition, any limitations in adequately visualizing all required anatomy should be documented in the written report. Guidance for required follow-up when fetal anatomy cannot be completely assessed was issued by a consensus panel on fetal imaging.²⁷ The recommendation is a follow-up examination in 2 to 4 weeks and, if adequate visualization again is not feasible, a comment should be made in the formal report regarding such limitations, with any future studies based on clinical indications. Patients should be advised of the encountered limitations and indications, or lack thereof, for future ultrasound studies.   

 A patient who presents for a gynecologic ultrasound infers consent to the performance of a complete ultrasound procedure. However, documentation of a patient’s express consent is warranted for vaginal ultrasound, particularly with sonohysterography, sonosalpingography, or ultrasound-guided puncture procedures.. A discussion regarding the limits of gynecologic ultrasound, both vaginal and abdominal approaches, is crucial to limiting liability exposure. If the sonologist is acting as a consultant, he or she should inform the patient that her primary physician is responsible for any clinical-care decisions based on the ultrasound findings.

During any pelvic exam, chaperones are recommended, whether the provider is female or male. Logically, that should also apply to vaginal ultrasound. However, the routine, habit, and custom in most diagnostic units is that female, and occasionally male sonographers, do not routinely have chaperones during sonographic studies. A chaperone is recommended when males perform vaginal, transperineal, or rectal studies. Patients should have the option for a chaperone during all such studies and should consent, either verbally or in writing, to the lack of a chaperone.

Conclusion

Ultrasound is integral to the contemporary practice of obstetrics and gynecology. Virtually all ob/gyn practices have ready access to ultrasound to enhance their patient care. Establishing standard procedures and practices, in accord with AIUM and ACOG guidelines and recommendations, enhances quality and limits liability exposure. Unfortunately, the potential for a liability claim involving ultrasound is ever-present. Adhering to best practices improves the defensibility of such a claim.

REFERENCES

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