Beyond The Basics: Respiratory Assessment & Diagnosis

BY DANIEL D. LIMMER, AS, EMT-P; JOSEPH J. MISTOVICH, MED, NREMT-P; & WILLIAM S. KROST, BSAS, EMT-P ON FEB 1, 2006

Your BLS ambulance is dispatched to a call for respiratory distress in a 78-year-old female who can't catch her breath. You arrive, determine the scene is safe and approach the patient, who is sitting on the edge of her bed in a tripod position and is visibly short of breath. You don gloves as you introduce yourself. She answers in three- or four-word sentences and tells you that she suddenly couldn't catch her breath.

Your partner applies oxygen, then observes medications on the nightstand. "Nasonex and Combivent," she notes as she holds them up. "My doctor says I have allergies," the patient tells you. You ask how long she has had the allergies, and she tells you "less than two weeks."

You find this a bit unusual as you consider her history and physical examination. The patient feels that she is in remarkably good health and took no medications at all until she developed allergies.

You note that her ankles appear a bit swollen. She says that the swelling is relatively new, and also confirms that she has been increasingly winded over the past week or so. She has added to the number of pillows she sleeps on until she finally ended up in the recliner for the past few nights. She looks amazed when you ask about weight gain--especially around the abdomen. "Why, yes," she says. "How did you know that?"

Her lung sounds reveal scattered wheezes in all lung fields and coarse rhonchi in the lower two-thirds of each lung. She feels some relief from shortness of breath with the oxygen you administer. Having arranged for an ALS intercept, you package the patient in the ambulance.

A paramedic enters the ambulance, agrees with your assessment of the patient's problem and begins care. She administers nitroglycerin and furosemide (a diuretic) en route to the hospital.

RESPIRATORY EMERGENCIES
Medical emergencies make up a majority of the calls in most EMS systems. Calls involving the respiratory and cardiovascular system are a significant component of this majority. The above-mentioned actual call underscores some critical components of medical emergencies: namely, that the patient history is vital and that things may not always be what they seem.

The title of this article--Respiratory Assessment and Diagnosis--may cause a few sparks, since many believe that EMS providers don't diagnose, or disguise the fact that we essentially do, using terms like "presumptive diagnosis" or "field impression."

If we hadn't made some sort of diagnosis, how did we know that the patient in the case study wasn't experiencing allergies? What keeps an EMS provider from blindly assisting with the patient's medications or giving a nebulized albuterol treatment?

The concept of differential diagnosis is one in which a wide range of conditions is considered and narrowed down to a select and manageable few. This process has also been referred to as moving from "possibilities to probabilities" when considering the cause of the patient's current condition.

The premise of this month's article is that medical emergencies are the detective cases of EMS. You must seek out the clues--some subtle, others obvious--which will lead you to a clinically enlightened decision, or diagnosis. And on this, you base your care.

THE RESPIRATORY HISTORY
It is said that 80% of the information we base our decisions on for the medical patient comes from the patient's history. The remaining (and important) 20% is based on the physical examination, which often tells us about the severity of the condition.

The chief complaint may be a revealing clinical clue to the patient's condition. Patients with a history of asthma will commonly describe the dyspnea as "tightness in my chest," whereas the congestive heart failure patient will often complain of a feeling of "suffocation" or a sensation of "air hunger." The COPD patient may complain of an "increased work effort to breathe" due to the increased respiratory muscular workload experienced by these patients.

In the congestive heart failure patient, dyspnea results from an inadequate delivery of oxygen necessary to meet the metabolic demands of the tissue. Early in the CHF disease process, the patient may only complain of dyspnea during activity, when the failing myocardium can't increase the myocardial workload to meet the increased demand precipitated by the activity. At this point, the patient complains of dyspnea accompanied by a feeling of suffocation, smothering or compression of the thorax at the level of the sternum. The patient may present with a compensating hyperventilation during the episode. As the CHF worsens over time, dyspnea and other associated complaints begin to occur at rest.

Psychogenic dyspnea is associated with patients suffering from a panic disorder or hysteria in which they overventilate by increasing the tidal volume (depth) and/or rate of ventilation (hyperventilation). A clue in the history that may distinguish this disorder is that dyspnea is not related to an increase in activity. The hyperventilating patient blows off an excess of carbon dioxide, resulting in a decrease in the arterial concentration of carbon dioxide (PaCO2). Subsequently, this produces cerebral vasoconstriction and a reduced cerebral blood flow state. This typically leads to a complaint of lightheadedness and dizziness, and, if a severe enough drop in cerebral blood flow occurs, a syncopal episode (faint).

Dyspnea may occur in a variety of settings and may be related to changes in position or a phase of the respiratory cycle. Dyspnea on inspiration is typically associated with an upper airway obstruction that could be due to a foreign body, or a result of edema or hematoma formation. Obstruction in the distal bronchi and bronchioles will produce expiratory dyspnea.

Paroxysmal nocturnal dyspnea (PND) is defined as a sudden onset of dyspnea that occurs while the sleeping patient is lying flat. The patient often wakes up coughing and assumes an upright position to relieve the symptoms. In the CHF patient, PND usually occurs one to two hours after lying down. This results as the gravitational pull on the body's fluid into the lower extremities is lost when the patient places his or her legs close to level with the heart. The fluid begins to collect in the lungs, causing sudden onset of dyspnea.

Orthopnea, very similar to PND, is also a complaint of dyspnea related to a recumbent position; however, the patient is not awakened from sleep by it. These patients typically prop themselves up with several pillows to avoid the onset of dyspnea. You often report this complaint as a "two-pillow" or "three-pillow" orthopnea. This complaint is associated with left ventricular failure.

Platypnea, just the opposite of orthopnea, is where the patient experiences dyspnea while in an upright position and finds relief when he lies down. This complaint is seen in patients with orthodeoxia, where arterial oxygen desaturation occurs when the patient is in an upright position. This condition is related to congenital heart defects, severe lung disease with venous to arterial shunts, or chronic liver disease.

Treopnea is experienced by a patient lying on his side. When he turns to the opposite side, the dyspnea is relieved. This complaint is usually associated with lung conditions or diseases that affect only one lung, such as obstruction or effusions.

Traditional processes and mnemonics such as SAMPLE and OPQRST (OPQRST is a subset of "signs and symptoms" in the SAMPLE history) provide considerable information about the patient's current condition. Unfortunately, this process can become rote for EMS providers and cause us to miss important facts and clinical avenues to explore.

Medications provide a snapshot of what the patient is currently being treated for. While they did not reflect the patient's underlying condition in the opening scenario, they did help to determine that the patient has been having symptoms prior to EMS intervention. Medications commonly accurately reflect patient conditions and provide valuable insight into the patient's pertinent past history.

"Events" is perhaps the most valuable, but least used and understood, of the SAMPLE components. Experienced clinicians often find great diagnostic value in this line of questioning. Events questions determine if the current condition had a sudden or a gradual onset. This can help include or remove some items from your list of differential diagnoses.

Respiratory conditions that are typically sudden in onset may include pulmonary embolus, spontaneous pneumothorax, foreign body obstruction, aspiration, hyperventilation and asthma attack.

More gradual onsets are seen with conditions like exacerbation of chronic pulmonary conditions (e.g., emphysema and chronic bronchitis), pneumonia and congestive heart failure. Note that not all patients realize the onset is gradual. In the opening scenario of this article, the patient said she suddenly developed difficulty breathing, but, in fact, it had developed over a period of time.

It is your exploration of the event surrounding development of the condition that helps narrow down causes. In the patient history, also be alert for signs of respiratory infections. These may indicate conditions like pneumonia and other infectious causes and the relation of infection to exacerbating chronic respiratory conditions. Be alert for signs of infection, including history or presence of fever, malaise, night sweats, cough (especially productive cough) and symptoms of the common cold.

Dyspnea on exertion (DOE) should also be investigated. Ask if the patient has been able to maintain his normal level of activity, and if he has experienced an increased level of difficulty breathing on exertion.

With any respiratory complaint, of course, a cardiovascular workup should be completed. With cardiac issues, the cause of many respiratory presentations and the common presentation of "silent MI" with only fatigue or difficulty breathing as a complaint, the examinations are concurrent in most cases. This may be especially true in women who present with atypical cardiac ischemia complaints.

A Note About Normal Breath Sounds
Normal breath sounds are heard in three categories: bronchial, bronchovesicular and vesicular.

Bronchial sounds are heard over the trachea and mainstem bronchi. These are harsh and somewhat high-pitched.

Bronchovesicular sounds are heard near the sternum and between the scapulae. Movement of air through the various bifurcations creates a slightly turbulent airflow pattern with a moderate pitch and is heard equally on inspiration and expiration.

Vesicular sounds are heard over the majority of the lung surface and are often described as "soft" or "light." Vesicular sounds are heard primarily during inspiration.

The value of knowing these breath sounds comes from knowing where they should be heard. When sounds are heard in places other than where they should be, this is abnormal. For example, if bronchovesicular sounds (louder, with greater pitch and intensity) are heard over lung tissue, consolidation is likely present.

PHYSICAL EXAMINATION
While the history provides a majority of the information for clinical decision-making, the physical examination should not be underestimated. The focused physical exam should focus on the respiratory system and other body systems affected by the respiratory system that may provide diagnostic clues as to the condition the patient is suffering from and the severity of the medical event.

The assessment process begins with a general impression of the patient. In this impression (sometimes called the "look test"), you will observe him for insight into the seriousness of his condition. A surprising amount of accurate information can be obtained as you approach the patient.

Identify the patient's mental status: Is he awake and responding appropriately? Unconscious or confused? The patient's mental status may help determine the severity of the respiratory dysfunction from which he is suffering. Poor cerebral oxygenation generally manifests itself early as restlessness and agitation. As the hypoxia worsens, the mental status continues to deteriorate to the point where the patient may become unresponsive. Hypercarbia (high carbon dioxide levels in the blood) typically causes the patient to become confused and disoriented.

Following assessment of mental status, observe the patient for abnormal positioning including the tripod position and Levine's sign, which indicate physical distress. Then observe the patient for work of breathing. This is the effort required by the patient to move air in and out. Increased work of breathing may be evidenced by use of accessory muscles, including the intercostal muscles, scalenes and sternocleidomastoids. These will be seen as retractions or tugging between the ribs, above the clavicles and sternum and prominence of the muscles on the lateral neck.

Patients with obstructive lung conditions may also exhibit pursed-lip breathing. By forcing air out through pursed lips, a back pressure is created (similar to PEEP--positive end expiratory pressure), which has some benefit in opening airways that are narrowed by constriction or mucus production. Some patients are taught to do pursed-lip breathing, whereas others do it spontaneously.

Finally, as you introduce yourself to your patient, note how many words he can speak without having to breathe in between. Does he seem winded at rest?

Your general impression combined with the initial assessment will determine what interventions are required immediately. At this point, administer oxygen, either by cannula, mask or BVM, depending on the patient's respiratory status. One of the most common, and most serious, mistakes is applying oxygen by non-rebreather mask to a patient who is breathing inadequately.

Adequate breathing is a function of rate and depth. Both must be adequate! The patient breathing six times a minute or the one breathing shallowly at 40 breaths per minute will both need assisted ventilations by BVM or pocket facemask with supplemental oxygen.

Whether you are at the first responder, EMT or paramedic level, the initial assessment is crucial. Do not move on from this assessment without ensuring adequate ventilation and oxygenation.

ASSESSMENT TECHNIQUES
Auscultation
One of the most common techniques for assessing lung sounds is auscultation. This technique is physically easy to perform with a stethoscope; however, interpreting and documenting the results is a chronic problem among EMS providers.

The lungs are contained within the chest cavity. The left lung has two lobes, the right lung three. Auscultation is accomplished by placing the diaphragm of your stethoscope over one of the lobes. Place the diaphragm gently against the chest and listen. While this sounds simple, there are some potential pitfalls, including:

Auscultating one side. Always auscultate one point on one side of the lung, followed by the corresponding point on the other lung. The points you listen to should move from side to side, not up and down.
Listening over bone. It is best to listen over areas where there isn't dense bone. Listening over the sternum or scapulae will interfere with obtaining lung sounds.
Hair and muscle interfere. Abundant chest hair can interfere with proper auscultation. Wetting the hair can reduce sounds that mimic lung pathologies. Patients who are shivering or have constricted muscles due to nervousness or injury may also have sounds that resemble abnormal conditions.
Listening over road noise. It is best to listen before you get the patient into the rig (unless the atmosphere at the scene is noisier). It is worth the investment to get the lung sounds early in the quieter environment.
Missing the lower lobes. If you haven't listened to lung sounds over the patient's lower back, you haven't listened to the lower lobes. The lower lobes are barely audible from the front.
Listening over clothes. You will not be able to obtain accurate lung sounds listening over anything from T-shirts to sweaters. Get down to skin level.

There is great variation in the terminology and clinical implications assigned to lung sounds. Traditionally, rales, rhonchi and wheezes were used to describe abnormal or adventitious sounds. "Crackles" is another term used to describe abnormal sounds.

Rales or crackles are terms used to describe the sound of sudden opening of collapsed small airways or the movement of excessive secretions or fluids as air passes through the airway. They are most commonly compared to the sound made by hair when strands are rubbed together. These sounds are often heard at the end of the inspiratory cycle.

Rhonchi, which continues to be a controversial term, are described as loud, lower-pitched, continuous sounds that may have a bubbling or rattling quality. They are often described as similar to the sound of Velcro being torn apart. Rhonchi, also known as sonorous rales, can be heard in both inspiratory and expiratory cycles.

Wheezing is described as a musical sound that can be heard on either or both inspiration or expiration. This sound is caused by air being moved forcefully through narrowed airways resulting from bronchospasm, mucosal edema or foreign bodies.

While many listen to breath sounds and record the basic sound heard, important points are often left out for both diagnosis and documentation. These include:

Where the sounds are heard in the respiratory cycle
Where the sounds are heard in the lungs
Whether the sounds are unilateral or bilateral
If the sounds clear or change with cough or other factors.

Palpation
Palpation should be used to identify pain, tenderness or the presence of subcutaneous emphysema. It is imperative to palpate the chest during deep inspiration, which is when abnormalities will be most obvious.

An easy clinical exam for EMS providers to perform is tactile fremitus. This is accomplished by placing the palm of the hand first on the patient's back and then the chest. Palpable vibrations are transmitted from the bronchial tree through the chest wall when the patient speaks. With your hands on the patient's back, ask the patient to say "ninety-nine" consecutively until told to stop. As the patient speaks, move your hands from left to right across the chest until variations in vibration patterns are felt. In areas of the lung where there is greater density, like in the pneumonia patient, vibrations (or fremitus) will be greater. In normal lung tissue, vibrations should be much less focal.

Pulse Oximetry
Reduced cost and easy field use have put pulse oximeters in most jumpkits and in the diagnostic arsenals of most providers. In truth, the diagnostic abilities of the pulse oximeter are limited and may provide a false sense of security with our more serious patients.

While pulse oximetry will tell us how much hemoglobin is bound, it won't provide information on how much is free (non-bound) oxygen or how much of the oxygen is available for offloading or utilization in the tissues of the patient in respiratory distress. In short, there is no dependable correlation between the level of distress felt by the patient and the saturation of oxygen in the blood.

Pulse oximetry readings can be used to monitor and document saturation readings over time and to make a possible correlation to improvements after interventions or worsening of the patient's condition. Caution should be taken when pulse oximetry is used for anything other than trending patient compensation or response to therapy.

Capnography
Although useful in all forms, capnography is most useful when quantitative and graphic, as in continuous waveform capnography. This form of capnography is most beneficial because it allows for continuous airway and ventilation monitoring, and it has been found to be especially useful during CPR. At the onset of cardiac arrest, carbon dioxide levels will drop far and fast. Despite cardiac arrest, the carbon dioxide levels will begin to rise with effective CPR; even more amazingly, they will return to near-normal levels with a return of spontaneous circulation (ROSC). Clinical studies have proved that end-tidal CO2 levels have been predictive of cardiac output and coronary perfusion pressure (CPP). As such, it can be deduced that since ETCO2 could determine cardiac output and CPP, it can also effectively measure compression effectiveness during CPR.

Edema and ascites
Patients with congestive heart failure may present with edema. We traditionally look for edema in the feet and ankles, and often find it. As common as this is, however, absence of pedal edema does not rule out CHF.

Edema will settle in any dependent area. The abdomen and sacral region are also common, but not as frequently assessed in the field as the ankles. This fluid in the abdomen is called ascites. Patients will report tight-fitting clothes and weight gain. In many cases of severe CHF, physicians will recommend that patients weigh themselves as one means of monitoring fluid retention and edema.

Sacral edema will be found in the patient who is on primary bed rest. The patient who is mobile and often in an upright position will present with lower feet and ankle edema due to the gravitational pull of fluid to the lower extremities. However, in the patient who is typically much less mobile and spends much of his time in a recumbent, Fowler's or semi-Fowler's position with his legs elevated to the same level of the heart, the fluid will collect in the sacral area, causing a dependent edema. If the patient spends much time on his side, the fluid will collect at the hip, producing evident dependent edema on the side on which the patient is lying.

APPLYING THE HISTORY AND PHYSICAL EXAM TO DIAGNOSIS
The charts above will help you apply the information from this article to patients and assessment techniques in the field. Remember that no patient matches every diagnostic criterion for a disease. In fact, few do.

Patients with multiple conditions (e.g., CHF plus chronic bronchitis) will pose challenges as you determine which condition is the root of the patient's breathing difficulty and choose the appropriate treatment(s).

Conclusion
By taking a consistent, accurate and focused approach to assessing respiratory conditions, appropriate clinical decisions can be formed and correct interventions can be administered.

Daniel Limmer, AS, EMT-P, is a paramedic with Kennebunk Fire-Rescue in Kennebunk, ME, and a faculty member at Southern Maine Community College. He is the author of several EMS textbooks and a nationally recognized lecturer.

Joseph J. Mistovich, MEd, NREMT-P, is a professor and the chairman for the Department of Health Professions at Youngstown (OH) State University, author of several EMS textbooks and a nationally recognized lecturer.

William S. Krost, BS, EMT-P, is an operations manager and flight paramedic with the St. Vincent/Medical University of Ohio/St. Rita's Critical Care Transport Network (Life Flight) in Toledo, OH.