Guest Post: Minute for the medical staff, part 2

By James S. Kennedy, MD, CCS, CDIP

Definitions matter

Many clinical documentation improvement (CDI) programs now look to capture risk-adjusted conditions which help improve the capture of a patient’s severity of illness and risk of mortality regardless of setting. Since risk-adjusted outcomes depends on the definitions of coded diagnoses, let’s discuss current literature which supports specific clinical terms:

Shock: a life-threatening, generalized form of acute circulatory failure associated with inadequate oxygen use by the cells. In assessing the potential presence of shock, abnormalities of the skin (degree of cutaneous perfusion); kidneys (urine output); brain (mental status) are examined. While arterial hypotension (defined as systolic blood pressure of less than 90 mmHg, or mean arterial pressure of less than 65 mmHg, or a decrease of greater than or equal to 40 mmHg from baseline), is commonly present, it should not be required to define shock. As such, lactate levels in shock states are typically less than 2 mEq/L (or mmol/L) in shock states. In neonates, significant shock stigmata, such as decreased capillary refill, mottling, cool extremities, and tachycardia, can define shock in the right clinical circumstance.

A common misperception that hypotension is essential to its diagnosis, represents a challenge in the diagnosis, documentation, and coding of shock. Compensated shock, for example, has a normal blood pressure and other shock indicators (e.g., elevated lactate level). Another challenge is that many patients die of shock, yet it is not documented as a terminal event. As such, given that lactate levels are being drawn more frequently in the emergency department, we must interpret the reason for any elevation.

A recent redefinition of septic shock in Sepsis 3, available at www.jamasepsis.com, requires the use of vasopressors to make the diagnosis. Given this requirement, recovery auditors are denying ICD-10-CM codes for shock if vasopressors are not used. This, however, contrasts with CMS’ definition of septic shock which allows a lactate level of 4 or more or just the documentation of septic shock as to qualify for the CMS severe sepsis or septic shock bundles. Given that AHA Coding Clinic for ICD-10-CM/PCSstates that coding is based on provider documentation only, not on clinical indictors, we must be consistent, repetitive, and insistent if we believe our patients meet our definitions of shock.

Be sure to note whether the shock is hypovolemic, cardiogenic, distributive, or obstructive in nature. If a patient has cardiogenic shock, ICD-10-CM-based risk adjustments also require that we document acute or decompensated systolic or diastolic heart failure to properly categorize mortality risk.

Acute kidney (renal) injury: Defined by an abrupt decrease in kidney function that includes, but is not limited to, acute renal failure, characterized by any of the following:

1. An increase in serum creatinine (SCr) by 0.3mg/dl within 48 hours;
2. An increase in SCr to 1.5 times the baseline, which is known or presumed to have occurred within the prior seven days; and/or
3. Urine volume of 0.5ml/kg/h for 6 hours.

Acute kidney injury and acute renal failure share the same code in ICD-10-CM

Acute kidney injury can be prerenal, renal, or postrenal in origin. If possible, document the underlying cause of the acute kidney injury, such as acute tubular necrosis, acute cortical necrosis, or acute tubulointerstitial nephritis, and its associated consequences, such as a metabolic acidosis, anuria, hyperkalemia, or a uremic metabolic encephalopathy.

Acute respiratory failure: Defined as a failure to ventilate or oxygenate (partial pressure of oxygen in arterial blood [PaO2] < 60; peripheral capillary oxygen saturation [SpO2] < 92%; percentage of oxygen saturation of aterial blood [SaO2] < 88%). While a ventilator is not required to treat acute respiratory failure, the patient will likely be on bilevel positive airway pressure (BiPAP), continuous positive airway pressure (CPAP) (except for patients with sleep apnea), high-flow oxygen, or 28% or higher fraction of inspired oxygen (FiO2) for a prolonged period of time.

Delirium and its underlying cause: Defined as a transient, usually reversible, cause of mental dysfunction manifested clinically with a wide range of neuropsychiatric abnormalities. The provider should describe the underlying brain disease causing the delirium, such as a toxic or metabolic encephalopathy or an exacerbation of an underlying neurodegenerative brain process (e.g., Lewy-body dementia). Avoid the word “encephalopathy” alone without an adjective describing its underlying cause.

Glasgow Coma Scale (GCS): ICD-10-CM allows the coding of each element of the Glasgow Coma Scale if documented by a physician, nurse, or emergency medical technician. As such, the GCS should be measured by nursing if there is any altered level of consciousness. Note that ICD-10-CM equates unconsciousness as coma if documented by a provider.

Thrombocytopenia, elevated protime/activated partial thromboplastin time (aPTT): Note the underlying cause of these abnormal coagulation studies, explicating documenting primary or secondary thrombocytopenia, primary or secondary coagulopathies, or disseminated intravascular coagulation. If these are due to a new liver disease or are associated with elevated liver function tests, note acute or subacute hepatic failure or any “shock liver.” If the patient is on any antiplatelet or anticoagulant agent, please describe to what extent these caused the patient’s bleeding.

Troponin elevation: Not every acute rise or fall of a troponin level at the 99th upper reference limit is an acute myocardial infarction (MI), especially in critically ill patients. If you believe that the criteria of the 3rd Universal Definition of Myocardial Infarction are met, then by all means document that the patient had a STEMI or NSTEMI. On the other hand, if these criteria are not met, avoid diagnosing an MI; use the term “troponin leak” or “nonischemic myocardial injury with necrosis,” not “demand ischemia.” Read the MI definition at www.tinyurl.com/2012UDMI.

Please discuss these principles with your hospital’s quality, coding, and/or clinical documentation improvement teams.

Editor’s note: This article originally appeared in Revenue Cycle Advisor. Dr. Kennedy is a general internist and certified coder, specializing in clinical effectiveness, medical informatics, and clinical documentation and coding improvement strategies. Contact him at 615-479-7021 or at jkennedy@cdimd.com. Advice given is general. Readers should consult professional counsel for specific legal, ethical, clinical, or coding questions. To read the first part of this article, click here.