When you approach him, he calms down enough to allow you to assess his vitals signs. His heart rate is 135 bpm and regular, respiratory rate is 22 bpm, blood pressure is 85 mmHg/palp, and his oxygen saturation is 91% on room air. You become more concerned. On examination, his skin and mouth appear dry, his neck veins are flat, and he has focal crackles in his right lower lobe on auscultation.
You administer oxygen 15 L by face mask, establish IV access and administer a 500 cc bolus of normal saline because of the hypotension and clear signs of dehydration. His finger-stick blood glucose reading is 145 mg/dL. You carefully move the patient onto the stretcher, down the front steps and into the ambulance. After the fluid bolus, the patient appears calmer.
Repeat vital signs are heart rate of 122, respiratory rate of 22 bpm and a systolic blood pressure of 100 mmHg. The oxygen saturation has improved to 100% with supplemental oxygen. You re-examine him; his lung exam remains unchanged. Your partner starts the ambulance, and you're on your way to the emergency department (ED). You breathe a sigh of relief that the vitals have improved, but your clinical concern is that this patient may have pneumoniaƒand you're right.
Understanding pneumonia from a prehospital perspective involves consideration of its pathophysiology, how it can present clinically and other common diseases that have similar symptoms. To help promote this understanding, we'll review treatment of pneumonia in the field, in the ED and in the hospital, along with special considerations regarding the presentation of pneumonia in children and older adults.
In general, there are two broad classifications of pneumonia. The first and most common is community-acquired pneumonia (CAP), which is pneumonia contracted outside of a hospital or long-term care setting. Nosocomial pneumonia, or health-care associated pneumonia, is contracted in a hospital or long-term care facility. Prehospital providers will undoubtedly come into contact with both forms of the disease.
Approximately 5.6 million cases of pneumonia are diagnosed in the U.S. every year.(1) In 2005, more than 1.3 million patients were admitted to U.S. hospitals with a diagnosis of CAP.(2) Of those, almost 70% were admitted through EDs. Almost 250,000 cases of nosocomial pneumonia are diagnosed per year, a proportion of those being ventilator-associated pneumonia, which occurs in patients who are intubated in the intensive care unit (ICU).(3) Annual costs of care for pneumonia are estimated at about $8.4 billion.(4) Of patients admitted with pneumonia, 5Ï10% will require ICU-level care.(5)
The Centers for Disease Control and Prevention (CDC) combines pneumonia and influenza when reporting data on mortality. In 2001, influenza and pneumonia together were listed as the seventh-leading cause of death in the U.S.(6) According to the Healthcare Cost and Utilization Project (HCUP) national inpatient sample, all-cause mortality for patients admitted with CAP is almost 5%.(2) Mortality from all forms of pneumonia increases as people get older. Although few infants and children actually die of CAP in the hospital (<1%), the in-hospital mortality rate for patients who are 85 and older is almost 10%.
Although anyone can get pneumonia, the risk increases with age. Past medical history and demographics are also important risk factors because certain demographics and medical problems can increase the risk of developing it. These risk factors include being male or single, smoking, and having heart disease, chronic obstructive pulmonary disease (COPD) or occupational dust exposure.(7)
Anatomy & Pathophysiology
Pneumonia is defined as an inflammation or infection of the lungs caused by viruses, bacteria, or chemical or physical irritants. Typically, CAP is caused by a bacterial infection, most commonly byStreptococcus pneumoniae. Additional causes of nosocomial pneumonia and ventilator-associated pneumonia include multidrug-resistant gram negatives and methicillin- resistantStaphylococcus aureus(MRSA).
What has been termed ˙atypical pneumoniaÓ is an infection usually caused by viruses (such as influenza or adenovirus) or by other bacterial pathogens (such asMycoplasma pneumoniae,Chlamydia pneumoniaeorLegionella pneumophilia). The age of the patient is sometimes a differentiating factor between typical and atypical CAP because young adults are more prone to the atypical causes, and the very young and elderly are more prone to typical causes.(8) Endemic fungi, such as histoplasmosis, cocciodomycois and blastomycosis, can also cause CAP.
Six major mechanisms lead to pneumonia
Inhaling infectious particles is the most common cause of CAP, whereas aspiration of oropharyngeal or gastric contents is the most common cause of nosocomial pneumonia. Patients at high risk for aspiration include those with impaired swallowing from neuromuscular diseases, stroke, altered mental status or seizures. The presence of nasogastric and gastrostomy tubes also increases the risk for aspiration of gastric contents.
Patients with such chronic diseases as human immunodeficiency virus (HIV) may developPneumocystis cariniipneumonia or„Mycobacteriumtuberculosis. Defects in pulmonary defenses include impaired cough reflexes due to use of sedatives, poor nutrition, stroke, neuromuscular diseases or impaired mucociliary transport. Mucociliary transport is poorer in older adults, smokers, those who are dehydrated, and those with concurrent infections, such as influenza. Anatomic changes, such as COPD, bronchiectasis and lung cancer, can also predispose some to pneumonia by preventing the clearance of bacteria. A blunted immune response is associated with older age, diabetes mellitus, malnutrition, hypothermia, hypophosphatemia and use of corticosteroids.
The diagnosis of pneumonia is commonly established by taking a detailed history, performing a comprehensive physical examination and obtaining tests, which usually include chest radiography and sometimes laboratory testing and CT scans.(10) Chest radiography may show an area of consolidation in a single lobe of the lung, which is more common in typical pneumonia.(11)
Consolidation can result in a change in how air is transmitted from that segment of the lung and what is commonly described as ˙decreased breath sounds.Ó Chest radiography may also show infiltrates. However, chest radiography, when performed early in the course of disease, may be negative and can lead to delays in diagnosis.(12) Chest radiography can also be initially negative when patients are dehydrated or the image quality is poor.
Common laboratory testing includes a complete blood-cell count and differential, (which includes a white blood cell count (WBC), hemoglobin and platelet count) blood chemistries (urea nitrogen and serum creatinine), electrolytes assay (sodium and potassium), glucose check and liver function tests to evaluate overall metabolism and organ function. Evaluation of oxygenation by pulse oximetry or arterial blood-gas analysis is important in patients because hypoxia and/or hypoxemia may be present.
A common laboratory finding in pneumonia is an elevated WBC, which can also indicate a higher severity of illness. Blood cultures are typically drawn for patients admitted to the hospital. Positive blood cultures indicating the presence of bacteria in the blood occur in 3Ï14% of cases overall but are much more likely in cases of severe pneumonia and nosocomial pneumonia.(13)
Other common tests prior to hospital admission include a sputum gram stain to determine the specific bacteria causing the pneumonia, antigen testing forpneumococcus and urine antigens forLegionella pneumophilia. Also helpful in determining pneumonia severity are blood urea nitrogen (BUN) and serum pH. High values in blood urea nitrogen are associated with concomitant dehydration and more severe pneumonia. Serum pH cases with an acidosis (pH < or =7.30) are more severe.
Assigning an official diagnosis of pneumonia typically requires testing in the ED and sometimes after admission to the hospital. Therefore, pneumonia is usually not diagnosed definitively in the prehospital setting.
Clinical Signs & Symptoms
Typical symptoms of pneumonia include productive or non-productive cough, fever, shortness of breath and chills. Patients may complain of chest pain, rigors (i.e., shaking with fever) or night sweats. Older adult patients and children are more likely to present with atypical symptoms, including abdominal pain and vomiting.(14) Other associated symptoms include headache and muscle aches. Specific types of pneumonia (such as Legionella) may also produce gastrointestinal symptoms, such as nausea, vomiting and diarrhea.
Symptoms commonly experienced by patients with pneumonia can be non-specific. Many illnesses can produce common symptoms of pneumonia. Table 1 (see„JEMS„ October 2007) lists a differential diagnosis for patients with cough, fever and shortness of breath; it also shows additional clues that can aid in differentiating these conditions in the prehospital setting.
Physical examination findings of pneumonia may include fever, crackles or rales on lung auscultation and tachypnea (i.e., high respiratory rate). Patients with aspiration pneumonia may have loud and rhonchorous airway sounds, indicating aspirated food contents in the upper airway, as well as focal lung sounds that reveal an area of inflammation or infection caused by the aspiration. Patients may also demonstrate altered mental status from hypoxia, dehydration or hypercarbia. Examination may reveal either peripheral or central cyanosis.
Assessing the Severity of Illness
Pneumonia has a wide spectrum of severity; some patients have only a cough and fever while others are critically ill. Untreated pneumonia can sometimes be lethal, and patients can die from hypoxia and overwhelming sepsis.
The majority of patients with CAP can be treated as outpatients. Social factors can also contribute to the decision to admit a patient despite a low risk of death. These factors include access to and the ability to take oral medications, ability to adhere to treatment, adequacy of home care and presence of dementia.(16)
In many situations, because prehospital providers may be the only providers who have knowledge of a patient's home environment, it's appropriate to communicate this information to either the nurse or physician who will care for the patient in the ED. Patients with nosocomial pneumonia will traditionally be treated as inpatients (if they aren't inpatients already).
After arrival at the hospital and diagnostic testing, risk-stratification tools help physicians assign a level of severity in pneumonia. These validated severity assessment tools include the Pneumonia Severity Index (PSI), CURB-65 (confusion, urea, respiratory rate, blood pressure and age > 65 years) and the CRB-65 (confusion, respiratory rate, blood pressure and age > 65).(15) These tools help determine the severity of illness and can guide decisions regarding the need for hospital admission.
The PSI (Table 2, see„JEMS October 2007) separates patients into five groups according to risk of death at 30 days. In general, hospital admission is recommended for groups IV and V, whereas patients in category III may be candidates for a brief admission to an observation unit. Outpatient therapy is recommended for groups I and II. A major limitation of the PSI is the emphasis placed on the patient's age. This can underestimate the severity of illness in younger patients. (Many of the elements of the PSI are unavailable in the prehospital setting.)
CURB-65 (Table 3 - see„JEMS„ October 2007) is a validated five-point system based on an equal weighting of the following elements: confusion, BUN > 20 mg/dL, respiratory rate > 20, low blood pressure, and age > or =65.(17,18) CURB-65 is somewhat easier to use than the PSI, which has 20 separate variables.(19)
The validated CRB-65 may be more useful to prehospital providers because it involves a four-point scale and its calculation doesn't require laboratory testing, such as the BUN.(20)
Prehospital Assessment & Care
The first steps in the prehospital assessment are obtaining a thorough history, assessing vital signs and level of consciousness, and performing a physical examination. Vital signs should include pulse oximetry, if available.
When assessing history, it's important to re-emphasize that what is eventually diagnosed as pneumonia in the ED or hospital can appear different in the prehospital setting. Even in the ED, the diagnosis of pneumonia can be a challenge, particularly in the subset of patients who don't have classic clinical symptoms or negative chest radiographs.
Prehospital care for patients with pneumonia or possible pneumonia is directed at improving symptoms and at treating hypoxia and hypotension. Given the broad list of potential diseases that can produce cough and fever, some of which are potentially life-threatening conditions, a common therapy that may help patients is application of supplemental oxygen. For patients with respiratory distress, establishing a definitive airway through orotracheal intubation may be necessary.
Establishing IV access can also be helpful in patients likely to require hospital admission. However, determining who needs IV access can be tricky. Certainly older adults and patients who appear critically ill are dehydrated or require IV medications may benefit from an IV line in the prehospital setting.
For patients with clear symptoms of pneumonia and signs of dehydration, such as dry lips or mouth, a normal saline fluid bolus may be helpful in improving hemodynamic status. In patients with symptoms of wheezing and shortness of breath and suspected acute asthma exacerbation or COPD, albuterol by nebulization may be helpful.
But what if the problem is actually congestive heart failure (CHF)? Distinguishing heart failure from asthma/COPD can be difficult, particularly in the back of a noisy ambulance. Both can present with lungs sounds consistent with acute wheezing and complaints of shortness of breath. However, some clues that increase the likelihood of heart failure include the presence of bilateral, symmetric leg swelling and bilateral rales at the lung bases, as well as an elevated jugular venous pressure as determined by neck vein distension. However, evaluation of the neck veins may be limited by a patient's body habitus.
It may also be useful to look at a patient's medical history or medication list. If a patient takes albuterol regularly or is a current or former smoker (as in the case of asthma/COPD), this may suggest that an asthma/COPD flare is more likely; conversely, if a patient has known heart failure and is on furosemide (Lasix) or bumetanide (Bumex), the patient may have a flare of their CHF.
Determining volume status in the field is a challenge, and if there's any question, it's probably best to establish IV access and not perform such interventions as the use of furosemide or IV fluids. Giving furosemide to patients who are already dehydrated or have undiagnosed electrolyte problems can potentially worsen a patient's condition, as can giving IV fluid to a patient experiencing a flare of CHF. It's always prudent to call online medical command for further direction when there's question or the patient is in extremis.
ED & Hospital Care
The use of antibiotics is a mainstay of treatment for all types of pneumonia in adults. Antibiotic choice for treating pneumonia is almost always empirical because it's rare that the causative organism is identified before selecting a specific antibiotic. Empiric therapy is chosen on the basis of most likely pathogens, risk for resistant organisms, severity of illness and patient's age. Care for outpatient pneumonia typically includes oral antibiotics.(21)
Care for patients admitted with pneumonia traditionally includes IV antibiotic administration and supplemental oxygen and frequently includes IV fluids. In severe cases, ventilatory assistance, such as intubation and bi-level positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP), is required.
Other supportive therapiesƒsuch as albuterol if patients have a combined picture of asthma/COPD or bronchospasm, decongestants (pseudoephedrine) or expectorants (guaifenesin)ƒare also useful to alleviate symptoms. Pneumonia is a common cause of sepsis, and critically ill patients will often require ICU-level care and sometimes vasopressors, such as dopamine or norepinephrine.(22)
Earlier administration of antibiotic therapy in the ED has been associated with improved outcomes. Two large retrospective studies have reported that antibiotic administration within four to eight hours of arrival was associated with decreased mortality and length of stay among older inpatients with CAP who had not received antibiotics as an outpatient.(23,24)
The Centers for Medicare and Medicaid Services and the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) uses administration of antibiotics within six hours of hospital arrival for admitted patients as a measure of quality in hospitals.(25) However, when patients present to or are brought to crowded EDs, they're more likely to experience delays in diagnosis and treatment of pneumonia.(26) The measurement of timing intervals in pneumonia has been controversial.(27) The Infectious Disease Society of America has advocated timely administration of antibiotics without recommending a specific time period.(28)
If pneumonia is either suspected by history or if the patient has been diagnosed with pneumonia in a physician's office and is being transported to the hospital, prehospital providers should communicate with ED staff about their suspicion of a diagnosis of pneumonia. For those with severe or nosocomial pneumonia, IV hydration and hospital admission are typically required, with the most critically ill being admitted to the ICU.
Infants & Children
Similar to adults, children with pneumonia often present with fever, productive cough and chills. However, children may also have symptoms of abdominal and chest pain. In comparison to adults, tachypnea (i.e., elevated respiratory rate) is a useful sign for the detection of childhood pneumonia and may be more specific than auscultation of crackles.(29)
The definition of tachypnea in children must be stratified by age. Table 4 (see„JEMS„ October 2007) shows the World Health Organization (WHO) guidelines for tachypnea by age group in children.(30)
Similar to adults, children with mild to moderate pneumonia are traditionally treated and discharged home from the ED. Children with more severe pneumonia need to be hospitalized. The British Thoracic Society guidelines have identified criteria for inpatient admission for children with pneumonia that include an oxygen saturation of less than 92%, cyanosis, difficulty breathing, grunting, signs of dehydration, or a family who can't provide appropriate observation and supervision.
The guidelines also state that infants and young children with a respiratory rate greater than 70 bpm and an inability to feed and older children with a respiratory rate greater than 50 bpm should be admitted.(31)
The causes of pneumonia are somewhat different in children than adults. Because viruses are the most likely cause for many cases of pneumonia in children, not all patients need antibiotics. However, deciding which patients don't need antibiotics can be difficult because ED testing often doesn't differentiate bacterial versus viral illness. In addition, some pneumonia patients have both mixed etiologies (i.e., both viral and bacterial etiologies or multiple types of bacteria).
Prehospital providers who transport children with pneumonia or potential pneumonia should be aware of the difference in clinical presentation and severity of illness in children. Assessment should be similar as for adults, and prehospital care should be aimed at supportive treatmentsƒsuch as supplemental oxygen and albuterol by nebulizationƒfor potential pneumonia or respiratory tract infections with evidence of wheezing.
Clinical features of pneumonia in older adults are considerably different from those seen in younger patients. A recent study compared the frequency of signs and symptoms among patients with pneumonia and found that patients older than 65 had fewer symptoms than those who were 18Ï44.(14) The older patients had a reduced frequency of fatigue, fever, chills, anorexia, sweats, headache, myalgia, nausea, sore throat, inability to eat, vomiting and diarrhea.
Another study confirmed that older adults with pneumonia are less likely to report a fever.(32) The presence of atypical symptoms in pneumonia can lead to delays in diagnosis.(33) Altered mental status is also common in older patients with pneumonia.
Aspiration is a frequent event in older adults, which is related to disorders that can be caused by acute or prior stroke, such as dysphagia (i.e., trouble swallowing) or a decreased cough reflex. In addition, as demonstrated by the severity of illness scoring systems, older age is an independent risk factor.
From a prehospital perspective, providers should realize that older adults with pneumonia are a high-risk population and that pneumonia can present atypically in this age group.
Pneumonia is a common disease associated with considerable morbidity and mortality. Although a diagnosis isn't typically made in the prehospital setting, prehospital providers should be able to generate a differential diagnosis for adults and children with classic symptoms of cough, fever and shortness of breath. Prehospital treatment for patients with pneumonia traditionally involves symptomatic management of hypoxia and concurrent bronchospasm, and often includes IV fluids for those who are more critically ill and rapid sequence intubation by credentialed providers for patients with respiratory failure. Providers should realize that pneumonia can present differently in various age groups. Additionally, a basic understanding of the pathophysiology of pneumonia, the severity assessment and treatment will aid in recognizing pneumonia cases in the field.
Jesse M. Pines,MD, MBA, MSCE, is an assistant professor of Emergency Medicine and a senior scholar at the Center for Clinical Epidemiology and Biostatistics at the University of Pennsylvania School of Medicine in Philadelphia. Contact him atpinesjes.uphs.upenn.edu
This continuing education activity is approved by the Center for Emergency Medicine of Western Pennsylvania Inc., an organization accredited by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS), for 1.5 hours credit for First Responder, Basic and Advanced providers. If you have any comments regarding the quality of this program and/or your satisfaction with it, please contact CECBEMS by mail at CECBEMS, 5111 Mill Run Road, Dallas, TX 75244; by phone at 972/387-2862; by fax at 972/716-2007; or by e-mail firstname.lastname@example.org.