Procedure Practice 12/15/00 - Coding Recommendations

Feature Article 12/15/00:

Congestive Heart Failure
and Related Cardiopulmonary Conditions

Congestive Heart Failure - Pulmonary Edema - Pleural Effusion
Acute Respiratory Failure - Mechanical Ventilation
  

This month, we examine the multiple coding issues involved in coding and sequencing congestive heart failure, pulmonary edema, pleural effusion, and acute respiratory failure. We review the basic pathophysiology of these conditions in order to understand how they are interrelated. We cover pertinent documentation issues, ICD-9-CM coding guidelines, and DRG assignment. We will also review the guidelines for a procedure often associated with the inpatient treatment of these conditions, mechanical ventilation.

Congestive Heart Failure

Congestive heart failure (CHF) refers to the inability of the heart to supply adequate blood output relative to the body's needs. In CHF, the heart suffers from decreased pumping ability, volume overload, and impaired filling of its chambers.

In a normal heart, blood flows from the right atrium to the right ventricle and into the pulmonary circulation for oxygenation. Oxygenated blood then returns to the heart via the right and left pulmonary veins into the left atrium. Blood then travels from the left atrium into the left ventricle. The left ventricle, the heart's primary pumping chamber, then moves the oxygenated blood to the aorta and systemic circulation.

CHF may affect either the right or left ventricle. Left heart failure is the inability of the heart to meet the blood and oxygen needs of the body. It occurs if the left ventricle has an overload of fluid due to the inability to pump out the blood it receives from the lungs to the rest of the body. Right heart failure is a result of left heart failure and occurs when the left ventricle has failed completely to contract.

The most common underlying heart conditions associated with CHF are cardiac ischemia (ischemic cardiomyopathy), dilated cardiomyopathy, valvular regurgitation, aortic stenosis, and severe hypertension.

When the heart fails, a number of adaptations occur in the heart and throughout the body. If the failure is chronic, the ventricles dilate in an effort to compensate for the heart's poor pumping ability. The ventricular enlargement causes a rise in diastolic blood pressure throughout the circulatory system. Chronically elevated diastolic pressures can cause capillary leakage (transudation) of fluid with resulting pulmonary or systemic edema. Lower cardiac output also reduces renal blood flow and the glomerular filtration rate within the kidneys, which in turn leads to sodium and fluid retention.

Patients with chronic stable CHF may experience acute exacerbations of the condition. Principal causes of these acute episodes include changes in therapy, patient noncompliance with treatment, excessive salt or fluid intake, cardiac arrhythmias, excessive physical activity, pulmonary emboli, acute infection, or progression of the underlying cardiac disease.
 

Signs and Symptoms

• Dyspnea (even at rest), orthopnea, hypoxia, respiratory acidosis
• Abnormal breath sounds such as crackles or rales
• Chronic nonproductive cough, worse when lying down
• Fatigue and weakness
• Ankle swelling or pitting edema of the lower extremities
• Evidence of interstitial edema or pleural effusion and cardiomegaly on chest x-ray
• Heart strain, enlargement, or ischemia on electrocardiogram
   

Treatment

• Diuretics (for example, Lasix) to reduce total blood volume
• Digoxin to strengthen contractility of the heart muscle
• Vasodilators to reduce ventricular load
• Antiarrhythmic therapy
• Oxygen supplementation
• Endotracheal intubation and mechanical ventilation
   

Documentation Issues

	If a patient had both CHF and hypertension, review documentation for a possible cause and effect relationship between the two conditions.
	If CHF is present with either rheumatic or valvular heart disease, documentation should indicate whether or not the CHF is secondary to either of these conditions.
	If pulmonary edema or fluid overload is present, CHF should also be documented if present.

Coding Guidelines

If a patient is admitted in acute respiratory failure associated with or due to CHF, 428.0, Congestive heart failure, is the principal diagnosis followed by 518.81, Acute respiratory failure, as a secondary diagnosis.

	If a patient has a history of CHF and is on medication for this condition while in the hospital, CHF should be coded as a secondary diagnosis, even though it may not be an active problem during the current admission.
	Assign 428.1, Left heart failure, for left heart failure without associated right heart failure.
	Unspecified heart failure is coded 428.9, Heart failure, unspecified.
	If dilated cardiomyopathy is accompanied by CHF, treatment is generally directed towards resolution of the CHF, and the principal diagnosis would therefore be CHF. It is appropriate to also code 425.4, Other primary cardiomyopathies, as a secondary diagnosis.
	CHF due to hypertension is coded to 402.01, Malignant hypertensive heart disease with CHF; 402.11, Benign hypertensive heart disease with CHF; or 402.91, Unspecified hypertensive heart disease with CHF.
	Heart failure with rheumatic heart disease is coded 398.91, Rheumatic heart failure.
	Heart failure following cardiac surgery is coded 429.4, Functional disturbances following cardiac surgery.

DRG Implications

	All codes for CHF, if listed as the principal diagnosis codes, group to DRG 127, Heart Failure and Shock.
	CHF as a secondary diagnosis is often (but not always) a complicating/comorbid condition.
	CHF may have respiratory sequelae and is often accompanied by respiratory conditions. It is important that the documentation clearly establish the cause of the patient's symptoms, that the appropriate codes are assigned, and that the most appropriate condition is sequenced as the principal diagnosis.

Pulmonary Edema

Pulmonary edema is the accumulation of fluid in the lung tissues and alveolar spaces of the lung. Pulmonary edema is broadly divided into two categories: cardiogenic pulmonary edema and noncardiogenic pulmonary edema.

Cardiogenic pulmonary edema is most commonly caused by left ventricular failure or mitral valve disease with associated CHF. In most patients with cardiogenic pulmonary edema, an underlying cardiac abnormality can be detected on physical exam, EKG, chest x-ray, or echocardiogram. Pulmonary edema may develop suddenly in the setting of chronic heart failure or it may be the first sign of underlying cardiac disease, usually an acute myocardial infarction.

A number of noncardiac conditions may also produce pulmonary edema. Causes of noncardiogenic pulmonary edema include opiate or barbiturate poisoning, sepsis, renal failure, shock, and disseminated intravascular coagulation. The condition may be a complication of stroke, skull fracture, or near drowning or it may be precipitated by the too rapid infusion of blood products or intravenous fluids.
 

Signs and Symptoms

• Acute onset or worsening of dyspnea at rest
• Productive cough with pink, frothy sputum
• Tachycardia, diaphoresis, cyanosis
• Pulmonary rales or rhonchi with expiratory wheezing
• Arterial hypoxemia
• Respiratory acidosis with a blood gas pH of less than 7.35
• HCO3 greater than 26 mEq/liter
• PaCO2 greater than 45 mm/Hg

In addition to the above symptoms, cardiogenic pulmonary edema is usually demonstrated by the following:

• Cardiomegaly on chest x-ray
• Presence of an S-3 gallop upon chest auscultation
• Elevated pulmonary artery wedge pressure over 25 mm Hg
• Increased interstitial markings, pleural effusions and Kerley B lines on chest x-ray
   

Treatment

• Diuretics
• Bronchodilators
• Oxygen supplementation
• Pain control medications
• Endotracheal intubation and mechanical ventilation
   

Documentation Issues

	The record must indicate whether the pulmonary edema is cardiac or noncardiac in origin.
	The etiology of the pulmonary edema must be stated in the chart if known.

Coding Guidelines

	Acute pulmonary edema of cardiac origin is a manifestation of CHF and is not coded as a separate condition. Assign code 428.0.
	Acute pulmonary edema associated with other heart disease such as acute myocardial infarction, acute or subacute cardiac ischemia, or coronary atherosclerosis, refers to left ventricular failure and is coded to 428.1. If left ventricular failure is present with right heart failure or CHF, then assign code 428.0.
	Acute pulmonary edema due to hypertensive heart disease with CHF is coded 402.01, 402.11, or 402.91 (see CHF coding guidelines above).
	Acute pulmonary edema with adult respiratory distress syndrome (ARDS) is noncardiogenic. The condition is included in the code for ARDS, 518.5.
	Chronic pulmonary edema codes to 514, Pulmonary congestion and hypostasis, unless otherwise directed in the Alphabetic Index. The medical record must clearly document that the pulmonary edema is a chronic noncardiac condition. Coders should consult with the attending physician if documentation is unclear.
	Acute noncardiogenic pulmonary edema is coded to disease of the lung or trauma as specified in the ICD-9-CM index.

DRG Implications

	The origin of the pulmonary edema must be documented for correct coding and DRG assignment.
	Cardiogenic pulmonary edema is coded to CHF, and the code groups to DRG 127, Heart Failure and Shock, if listed as the principal diagnosis.
	The codes for noncardiogenic pulmonary edema if used as a principal diagnosis (506.1, 514, and 518.4) group to DRG 87, Pulmonary Edema and Respiratory Failure.
	The code for noncardiogenic pulmonary edema as a principal diagnosis groups to DRG 475, Respiratory System Diagnosis with Ventilator Support, if paired with a procedure code for continuous mechanical ventilation.

Pleural Effusion

The lungs are located in the right and left pleural cavities of the body and are surrounded by a double layer of protective membranes (the pleura). The visceral pleura lie tightly against the surfaces of the lungs, and the parietal pleura line the walls of the right and left pleural cavities. The pleura secrete a small amount of lubricating fluid that lies between them in the interpleural space.

Pleural effusion is the abnormal accumulation of fluid in the interpleural space. The major types of effusion are transudates, exudates, empyema, and hemothorax. Transudates are most often due to CHF, which is the most common cause of pleural effusion. Exudates are most often caused by bacterial pneumonia or neoplasm. Empyema is caused by direct infection of the pleural space, causing the pleural fluid to appear purulent or turbid. Hemothorax is the presence of gross blood in the pleural space, usually as a result of chest trauma. In the absence of trauma, grossly bloody pleural fluid may be due to malignancy or possibly pulmonary embolism and infarction.
 

Signs and Symptoms

• Pleuritic chest pain
• Dyspnea and nonproductive cough
• Fever
• Chest x-ray findings positive for pleural effusion
   

Treatment

• Corticosteroids
• Diuretics
• Oxygen supplementation
• Aspiration of pleural fluid via thoracentesis
• Endotracheal intubation and mechanical ventilation
   

Documentation Issues

	If pleural effusion is documented, review the course of treatment in the medical record. Since CHF is the most common cause of pleural effusion, the medical record will likely reflect appropriate treatment for the CHF with subsequent resolution of the associated pleural effusion.
	If the pleural effusion is not associated with CHF, the record must document the cause of the effusion, if known.

Coding Guidelines

	In cases of pleural effusion with CHF, CHF is always the principal diagnosis.
	Pleural effusion associated with CHF is often minimal and treated by controlling the patient's heart failure. In these cases, the pleural effusion should not be coded separately unless it is specifically evaluated or treated, for example, via thoracentesis or placement of a chest tube for drainage.
	Do not assign a code for pleural effusion that is documented only as an x-ray finding.
	If the pleural effusion was evaluated with special decubitus view x-rays, or treated via chest tube placement or thoracentesis, it is acceptable to assign 511.9, Unspecified pleural effusion, as a secondary diagnosis code.
	Query the physician regarding the cause of the pleural effusion. If it is known, assign the most specific code as directed by the ICD-9 Index.

DRG Implications

	A principal diagnosis code for unspecified pleural effusion (511.9) without a complication or comorbidity groups to DRG 86, Pleural Effusion.
	The code for unspecified pleural effusion as principal diagnosis accompanied by a complication or comorbidity code groups to DRG 85, Pleural Effusion with Complication/Cormorbidity.
	A principal diagnosis code for pleural effusion with an accompanying procedure code for mechanical ventilation groups to DRG 475, Respiratory System Diagnosis with Ventilator Support. Thoroughly review documentation to be certain that the pleural effusion is not due to a nonrespiratory condition such as CHF.
	Unspecified pleural effusion coded as a secondary diagnosis is often a complication or comorbid condition that affects DRG assignment.

Acute Respiratory Failure

Acute respiratory failure (ARF) is defined as respiratory dysfunction resulting in abnormalities of tissue oxygenation or carbon dioxide elimination severe enough to threaten or impair vital organ functions. Causes of ARF include CHF, acute exacerbation of chronic pulmonary diseases (for example, COPD, asthma), pneumonia, pulmonary embolus, pneumothorax, chest trauma with resultant flail chest, drug or alcohol overdose, and neuromuscular disorders such as spinal cord injury and myasthenia gravis.
 

Signs and Symptoms

• Signs and symptoms of the underlying disease or condition
• Tachycardia (heart rate > 120 beats per minute)
• Dyspnea
• Cyanosis
• Restlessness, confusion, anxiety, delirium and tremor
• Rapid deep breathing (respiratory rate > 24 per minute)
• Hypertension
• Cardiac arrhythmias
• ABG values (see documentation issues below):
  • PO2 < 60 mm Hg (hypoxemia)
  • PCO2 > 50 mm Hg (hypercapnia)
  • pH < 7.35 (respiratory acidosis)
  • HCO3 < 22 mEq/liter
  • O2 saturation < 89%
     

Treatment

• Establishment or maintenance of clear airways by suction, bronchodilators, or tracheostomy
• Therapy to address the underlying disease
• Antibiotics for infections that may be present
• Anticoagulants if the suspected cause is pulmonary emboli
• Oxygen supplementation
• Monitoring respiratory status with serial ABGs and/or O2 saturation levels
• Endotracheal intubation and mechanical ventilation
   

Documentation Issues

Arterial blood gas criteria for respiratory failure are not absolute. Patients with chronic pulmonary diseases such as COPD, asthma, and pulmonary fibrosis often have associated chronic respiratory failure due to their decreased lung function. The chronic failure may be reflected in changes in these patients' baseline arterial blood gases (ABGs). The ABG values listed above should serve only as documentation clues for the coder that prompt discussion with the attending physician if the diagnosis of acute respiratory failure is being questioned.

The underlying cause of the acute respiratory failure, if known, must be documented in the medical record. Always speak with the physician if the documentation is conflicting, confusing, or otherwise unclear.

Coding Guidelines

	The diagnosis of acute respiratory failure should never be made on the basis of ABG results alone. Coding must be based on physician documentation. If a diagnosis of respiratory failure is suggested by the patient's ABG values, speak with the physician.
	Respiratory failure following surgery or trauma is coded 518.5, Pulmonary insufficiency following trauma and surgery.
	The fact that respiratory failure was managed without intubation and mechanical ventilation does not preclude coding this diagnosis if it is appropriately documented by the attending physician.
	Provided that the circumstances of the admission support such a decision, respiratory failure may be the principal diagnosis if either of the following applies: Respiratory failure is due to or associated with a respiratory condition; Respiratory failure is due to or associated with a chronic non-respiratory condition.
	Respiratory failure may not be the principal diagnosis if any of the following apply: Respiratory failure is due to or associated with an acute exacerbation of a chronic non-respiratory condition (the non-respiratory condition is sequenced first). Respiratory failure is due to or associated with an acute non-respiratory condition (the non-respiratory condition is sequenced first). Respiratory failure is due to or associated with a drug or alcohol overdose (assign the appropriate poisoning code as the principal diagnosis followed by the respiratory failure).

DRG Implications

	The code for respiratory failure as a principal diagnosis groups to DRG 87, Pulmonary Edema and Respiratory Failure.
	Respiratory failure as a secondary diagnosis may be a complicating or comorbid condition that affects DRG assignment.
	If paired with a procedure code for mechanical ventilation, a principal diagnosis code for respiratory failure groups to DRG 475, Respiratory System Diagnosis with Ventilator Support.
	A procedure code for mechanical ventilation paired with a principal diagnosis code for a non-respiratory condition does not group to DRG 475; therefore, it is important to determine the underlying cause of the respiratory failure and to properly sequence all diagnoses.

Mechanical Ventilation

Mechanical ventilation is a process by which gases are moved into the lungs via a device that assists respiration either by augmenting or replacing the patient's own ventilatory efforts. Either a tracheostomy or insertion of an endotracheal tube is required to deliver ventilatory assistance. The patient then receives variable degrees of mechanical ventilation to meet respiratory requirements in an uninterrupted fashion.

Mechanical ventilation is indicated for patients with severe respiratory illness or complications that result in severe oxygen and carbon dioxide exchange abnormalities. Apnea, acute hypercapnia that cannot be quickly reversed with conservative therapies, and progressive patient fatigue with respiratory effort are examples of critical situations that warrant mechanical ventilation. Generally positive-pressure, volume-cycled ventilators are used to provide support. Critical ventilator settings include mode of ventilation, tidal volume, frequency, inspiratory flow rate, sensitivity, and inspired oxygen concentration.
 

Common Modes of Mechanical Ventilation

• Assisted mechanical ventilation (AMV) or assist/control (A/C) is a ventilatory mode in which the ventilatory frequency set on the ventilator serves as a backup rate, but the patient may trigger the delivery of additional positive-pressure ventilator breaths.
• Continuous mechanical ventilation (CMV) provides ventilation at a specified rate for patients who are apneic.
• Intermittent mandatory ventilation (IMV) is a technique in which the rate set on the ventilator serves as a backup rate, but the patient is able to augment the minute ventilation by taking spontaneous breaths through a one-way valve from a reservoir. The ventilator breaths are usually delivered between the patient's spontaneous breaths.
• Positive end-expiratory pressure (PEEP) is the addition of positive airway pressure delivered by the ventilator at the end of exhalation. This technique is often used to treat patients with diffuse parenchymal lung disease such as adult respiratory distress syndrome.
• Pressure support ventilation (PSV) augments the patient's own respiratory efforts with a specific amount of positive airway pressure delivered by the ventilator.
   

Documentation of Treatment

Patients on a mechanical ventilator receive ventilator breaths via an endotracheal tube or a tracheostomy. The intubation or the tracheostomy will be documented in physician progress notes or on a separate procedure or operative report. Lung aeration is evaluated regularly by lung auscultation, which may be performed by the physician, nursing or cardiopulmonary services staff, and is subsequently documented in progress notes or on ventilation flow sheets. Serial chest x-rays will document lung status and verify correct placement of the endotracheal tube. Physician orders, nursing notes, and respiratory therapy records will document the initiation and cessation of mechanical ventilation, the type of ventilator, mode of delivery, pressure support, rate of controlled respiration, and the extent the ventilator assists or controls the patient's respirations. Other monitoring and treatment associated with mechanical ventilation include ABGs, oximetry, and endotracheal or tracheal suctioning.
 

Coding Guidelines

	Mechanical ventilation is coded to 96.70-96.72, Other continuous mechanical ventilation. The 4th digits reflect the length of time the patient was on the ventilator as follows: 96.70-Continuous mechanical ventilation of unspecified duration; 96.71-Continuous mechanical ventilation for less than 96 consecutive hours; 96.72-Continuous mechanical ventilation for 96 consecutive hours or more.
	Calculate the number of ventilation hours for patients with endotracheal intubation as follows: Begin counting from the start of endotracheal intubation. The hours of mechanical ventilation end when the patient is extubated. If the patient was intubated before admission, begin counting the mechanical ventilation hours from the time of admission. If a patient was transferred while still intubated, the hours of mechanical ventilation end at the time of discharge. For patients begun on ventilation via endotracheal intubation who subsequently underwent tracheostomy, begin counting mechanical ventilation hours with the endotracheal intubation and stop when the ventilator is turned off.
	Calculate the number of ventilation hours for patients with tracheostomy as follows: Begin counting the hours when mechanical ventilation was started. The ventilation period ends when the ventilator is turned off. If a patient received tracheostomy prior to admission and was on mechanical ventilation at the time of admission, begin counting hours from the time of admission. If a patient was discharged while still on mechanical ventilation via tracheostomy, the ventilation period ends at the time of discharge.
	Category 96.7 specifically excludes other types of respiratory therapy, such as bi-level airway pressure, continuous negative pressure ventilation, continuous positive airway pressure, intermittent positive pressure breathing, or oxygen administration via face mask, nasal cannula or nasal catheter. These therapies are coded to category 93.9.
	Code any associated endotracheal tube insertion (96.04).
	Code any associated tracheostomy (31.1-31.29).
	Ventilator support provided during surgery is considered integral to the surgical procedure and is not coded separately.

DRG Implications

	Documentation must clearly indicate the type of respiratory assistance provided in order to ensure correct coding.
	A respiratory system principal diagnosis code with a code for mechanical ventilation results in DRG 475, Respiratory System Diagnosis with Ventilator Support. Documentation must clearly indicate that a respiratory system diagnosis is the principal diagnosis.
	Addition of a tracheostomy code results in assignment to DRG 482, Tracheostomy for Face, Mouth and Neck Diagnoses, or to DRG 483, Tracheostomy Except for Face, Mouth, and Neck Diagnoses.

Practice Makes Perfect!

Are you ready for some hands-on practice? Assign the correct ICD-9-CM diagnosis and procedure codes for the coding scenarios on our Procedure Practice page and compare your answers with our coding recommendations. Good luck!

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Acute Respiratory Failure - Mechanical Ventilation
  

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