Documentation of medical necessity

Part 3 of 3

Acute chest pain, acute coronary syndrome, acute myocardial infarction and bronchospastic conditions are discussed.

Our last two columns in November and December 2012 discussed clinical indicators of inpatient medical necessity for patients admitted with certain problematic, high audit-risk conditions. This month's column is the third in this series and completes that discussion.

“Medical necessity” is a vague standard, subject to broad interpretation based on clinical practice and judgment. Essentially, it means an illness must be severe enough, and the required services intense enough, that care can only be given safely and effectively in the hospital.

Photo by Thinkstock
Photo by Thinkstock.

To provide some objective guidance, industry-standard guidelines have been developed over the past 30 years based on medical literature and professional practice guidelines. The most recognized and frequently used are the InterQual and Milliman criteria, which have been validated by research and decades of clinical use. These guidelines are intended to be used as screening tools, so clinical judgment with supporting documentation of medical necessity should take precedence. They are not intended as clinical practice standards of care or replacements for physician judgment and expertise.

Some typical parameters for inpatient medical necessity in common problematic conditions are discussed below.

Acute chest pain, acute coronary syndrome (ACS), acute myocardial infarction (AMI)

The evaluation and management of patients with these problems poses clinical and documentation challenges. Rapid technologic advances have changed both pathophysiologic understanding and expectations for a setting that provides effective care and sufficiently regards patient safety.

Patients presenting with acute chest pain represent a group with high risk but low frequency of potentially life-threatening conditions. No one wants to “miss” or delay treatment for unstable angina or AMI (whether ST-elevated MI [STEMI] or non-ST-elevated MI [NSTEMI]). Current guidelines indicate that most patients who need immediate evaluation of chest pain can be managed initially in observation if all of the following criteria are met:

  • Chest pain relieved prior to admission orders
  • Vital signs stable
  • Electrocardiogram (EKG) showing no significant findings or unchanged from prior EKG
  • Unremarkable chest X-ray for acute disease
  • Normal cardiac markers, especially troponin level in non-ischemic range

Documentation of only “atypical” or “nonspecific” chest pain, “angina,” or “rule out MI” does not support inpatient admission.

On the other hand, the following confirmed or suspected findings clearly justify inpatient care, assuming that clinicians provided aggressive recommended management consistent with the diagnosis:

  • “ACS” with left bundle branch block (new or undetermined age)
  • Significant EKG changes of:

In other, less certain cases, it is essential to document your clinical reasoning for, and management plans requiring, an inpatient admission. Keep in mind that “unstable angina” is a key diagnostic term that supports inpatient status whenever characterized by increasing severity, duration, frequency, or intensity. Also, for coding purposes, ACS is considered simply “unstable angina,” so if an NSTEMI is suspected, it needs to be documented. This is most confusing when the significance of an elevated troponin level goes unclarified.

Any reference to actual or suspected cardiac ischemia in conjunction with acute congestive heart failure, syncope, hypertensive crisis or aortic stenosis implies inpatient care is needed.

Remember that the patient must require the currently recommended management for serious, potentially life-threatening unstable angina or ACS to support an inpatient admission with these diagnoses. Anything less implies he or she could be managed in observation.

Bronchospastic conditions

The inpatient clinical criteria for asthma, chronic obstructive pulmonary disease (COPD) exacerbation or other causes of acute bronchospasm are well delineated. The following would typically qualify for inpatient admission:

  • Failed outpatient management for two or more days
  • Peak expiratory flow (PEF) <40% at any point
  • PEF <80% and lack of response to three doses of inhaled short-acting beta-agonist
  • Room air pO2 less than 60 mm Hg or pulse oximetry less than 90%
  • Arterial blood gas (ABG) showing pCO2 greater than 50 mm Hg and/or pH less than 7.30

Otherwise, unless the reason for inpatient care is clearly identified, observation care would usually be expected.

It is common to miss the opportunity to obtain room air pulse oximetry or ABG, as well as the necessary PEF measurements before and after three doses of short-acting beta-agonists. PEF can easily be measured at the bedside by a nurse or respiratory therapy professional using a simple, hand-held, peak-flow meter. These assessments are important quality-of-care indicators and management tools; it is most important to provide these during the initial emergency department presentation and management of patients.

The expected medically necessary inpatient care includes, at a minimum:

  • Supplemental oxygen with pulse oximetry or ABG
  • Bronchodilator nebulizer (including metered dose inhaler) every four hours or more
  • Corticosteroids given orally, or intravenously three times per day


Always be sure to document your clinical reasoning for an inpatient admission with specific reference to the clinical findings that support your decision. If you honestly expect the patient to require more than 24 hours of inpatient care, document this fact and ensure that such inpatient services are actually provided. When the case for inpatient medical necessity is weak, it may be prudent to use observation care before finalizing an admission decision, especially if advice from case management will later be available.