Documentation of medical necessity

Last month's column discussed the clinical indicators of inpatient medical necessity for patients with pneumonia and cardiac arrhythmia. “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.

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.

Photo by Thinkstock
Photo by Thinkstock.

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

Congestive heart failure (CHF)

Objective criteria supporting inpatient admission for CHF are vague, controversial and still evolving. From a clinical standpoint, a patient with an acute exacerbation/decompensation of CHF needs inpatient care. This decompensation would be manifested by severe dyspnea, pulmonary edema, tachypnea (respiratory rate 30 breaths per minute or more), significant hypoxia with room air pO2 of 60 mmHg or less (equivalent to a pulse oximetry reading less than 90%), need for multiple intravenous (IV) doses of loop diuretics (like furosemide) or need for ICU care. Suspected or confirmed acute cardiac ischemia or infarction with worsening CHF is certainly reason for inpatient care, if clearly documented.

In less obvious cases, be sure to document your clinical reasoning for an inpatient admission with specific reference to the clinical findings that support your decision. It may be helpful to include the amount of any recent weight gain. Remember that the services provided must also require inpatient care. For example, if a patient only needs one dose of IV diuretic, it would be very difficult to justify inpatient admission.

If you are honestly convinced at the time of admission that the patient will probably require more than 24 hours of inpatient care, document your conviction clearly, since Milliman/InterQual suggests this cutoff as a benchmark for inpatient medical necessity. It would be expected that all of the following were provided for the inpatient with CHF, unless there were a clear explanation why not: continuous cardiac monitoring and supplemental oxygen with pulse oximetry; more than two doses of IV diuretic; beta-blocker and ACE inhibitor or angiotensin receptor blocker; daily weight checks; and deep venous thrombosis prophylaxis.

Syncope and presyncope

Syncope is the sudden spontaneous loss of consciousness followed by quick recovery without residual effects. Presyncope is considered clinically equivalent to syncope. Most cases are the result of benign orthostatic hypotension or vasovagal response. However, syncope may also be a harbinger of a serious, potentially life-threatening condition such as ventricular arrhythmia, high-degree heart block, critical aortic stenosis, acute blood loss (e.g., acute gastrointestinal bleeding), pulmonary embolism, intracranial hemorrhage and others. Seizure may also be considered as a cause, especially if the episode is unwitnessed. Since it is defined as having no residual effects, true syncope is rarely caused by stroke or transient ischemic attack unless the vertebrobasilar system is involved.

In general, the following circumstances support inpatient admission but should be clearly documented as a suspected cause:

  • known underlying cardiac disease including CHF, ischemic or valvular heart disease;
  • suspected or confirmed cardiovascular drug-induced syncope;
  • high-degree atrioventricular (AV)-block (Mobitz type II or third degree) or any documented pause in cardiac rhythm of three seconds or more;
  • persistently low systolic blood pressure (less than 90 mm Hg) or pulse less than 60 beats/minute during initial presentation;
  • hematocrit/hemoglobin less than 25%/8.0 g/dL; and
  • acute gastrointestinal bleeding or other suspected cause of acute blood loss.

Patients who have “unexplained” syncope without any of these findings, or those considered to have a likely “orthostatic” or “vasovagal” cause, are good candidates for initial monitoring and evaluation in an observation setting. In all cases, whether inpatient or observation, continuous cardiac monitoring is required.

Transient ischemic attack (TIA)

TIA is a symptom of impending or possible subsequent stroke and is defined as a focal neurologic deficit lasting less than 24 hours. It has the same evaluation and management concerns as stroke. Most TIAs last less than one hour. Acute abnormal imaging findings (computed tomography or magnetic resonance) confirm that a stroke has occurred. Physicians sometimes forget that a focal neurologic deficit lasting more than 24 hours from onset (not from presentation) is a stroke, not TIA, even in the absence of imaging findings. Inpatient admission for stroke would almost always be considered clinically appropriate.

The pathophysiology and implications of TIA are the same as stroke: thrombosis, thromboembolism or other vascular occlusion. Since TIA is really a symptom of these underlying conditions, physicians should document these suspected, likely or possible causes of TIA (if stroke is not confirmed) to properly reflect the true severity and complexity of the patient's condition. Remember, too, that vertebral/basilar artery “syndromes” will be classified as TIA, so the associate stenosis or occlusion of these vessels needs to be identified as the cause.

Evidence-based clinical criteria and expert consensus opinion now offer clear guidance for the action required for TIA: the National Stroke Association's ABCD2 TIA score (see Table). A score of more than 3 is associated with a dramatic increase in the short- and long-term risk of subsequent stroke and necessitates immediate action.

Inpatient care for stroke or TIA would necessitate all of the following:

  • neurologic assessment (“neuro check”) at least every four hours;
  • aspirin, antiplatelet, or anticoagulant therapy (unless a contraindication is documented) and
  • comprehensive evaluation for underlying causes.


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.