Recognize the signs and symptoms of pneumonia and understand how capnography can be used to guide treatment for pneumonia and sepsis.
Pneumonia is the leading cause of infectious death in industrialized countries . According to the American Lung Association, pneumonia causes more than 1 million hospitalizations and more than 50,000 deaths each year.
Much of the morbidity, mortality, and health care costs associated with pneumonia occur when it progresses to sepsis. EMS plays an important role in identifying pneumonia, identifying sepsis caused by pneumonia and treating the respiratory and circulatory complications associated with pneumonia and sepsis.
Here are three things you should know about pneumonia and sepsis:
1. Pneumonia causes inflammation of a section of lung that impairs air exchange
Pneumonia is caused by an immune response to pathogens that colonize an area of the lung. The inflammatory response causes fluid or pus to accumulate in the alveoli and prevents oxygen exchange over the area affected. Pneumonia can be caused by a bacterial, viral or fungal infection.
The most common route of pneumonia infection is aspiration of saliva or nasal secretions that harbor bacteria. Pneumonia can also be acquired from inhaling droplets containing a bacteria or virus. Streptococcus pneumoniae is the most common bacterial cause of pneumonia, while influenza and respiratory syncytial virus are the most common causes of viral pneumonia .
Immunocompromised patients are also at risk of pneumonia by inhaling fungal spores.
A remote infection, such as a urinary tract infection, or infection from an indwelling catheter or tracheostomy, can also travel to the lungs and cause pneumonia.
Aspiration of gastric contents is a non-infectious cause of pneumonia, which occurs when patients who cannot protect their upper airway vomit. Known as chemical pneumonitis, acidic gastric contents produce burning to the tracheobronchial tree when aspirated, followed by inflammation and impaired gas exchange in the lungs.
Elderly, immunocompromised patients, patients with chronic lung disease and smokers have an increased risk for pneumonia . A depressed gag reflex, such as from alcohol intoxication, overdose, head injury, stroke or seizure increases the risk of aspiration pneumonia . Patients whose upper airway is bypassed, such as from intubation or a tracheostomy, are also at high risk for aspiration pneumonia .
The severity of pneumonia from any cause depends on how much surface area of the lung is affected by inflammation, which is based on the virulence of the invading pathogen, the strength of the immune response and the patient’s overall health .
2. Look for a gradual onset of difficulty breathing, fever and localized abnormal lung sounds to identify pneumonia
Patients with pneumonia usually report a gradual onset of difficulty breathing, along with fever and chills, a productive cough and chest pain associated with the cough. Localized or unilateral crackles, rhonchi, wheezes or diminished breath sounds may be heard over the affected area of the lungs . However, elderly and immunocompromised patients may not have a fever with infection. Cough reflex also diminishes with age, so elderly patients with pneumonia may not have a productive cough. Consider pneumonia as a differential diagnosis in elderly patients with vague complaints, such as altered mental status.
A definitive pneumonia diagnosis is made by chest X-ray in the hospital.
Pneumonia can cause hypoxia and increased work of breathing. Assess skin color and pulse-oximetry to identify hypoxia and administer oxygen via nasal cannula or nonrebreather mask to titrate a pulse oximetry reading of 94 percent.
For patients who are awake and protecting their airway, CPAP can improve work of breathing and oxygenation in patients who remain hypoxic after supplemental oxygen. CPAP works by increasing pressure in the lungs and improves oxygenation and ventilation across the area affected by pneumonia and recruits collapsed alveoli surrounding the affected area .
In addition to auscultating lung sounds, waveform capnography is a useful tool to identify bronchospasm in pneumonia. Patients with wheezes or diminished breath sounds, along with a slurred, shark fin appearance on the capnogram, have constricted lower airways and benefit from nebulized albuterol.
The more pronounced the shark fin on the capnograph, the more severe the bronchospasm. Shifts in the capnography waveform toward or away from a normal rectangular shape show how well the patient is responding to treatment.
Pneumonia can cause respiratory failure and decreased mentation. Patients may have secretions in their upper airway that require suctioning and require assisted ventilation with a bag valve mask.
Waveform capnography can be used with a bag valve mask or advanced airway to determine airway patency and effective air exchange in the lungs. Capnography is also the most reliable method to confirm advanced airway placement and provides continuous feedback on respiratory rate to help avoid hypo or hyperventilation.
Patients with pneumonia are also frequently dehydrated . Consider administering IV fluids to suspected pneumonia patients who are hypotensive, feel weak, have dry mucus membranes or poor skin turgor.
3. Look for vital sign changes and abnormal ETCO2 to identify pneumonia with sepsis
When the body’s immune response to pneumonia becomes systemic and causes sepsis, the respiratory compromise may be further complicated by metabolic acidosis and shock. Sepsis is a systemic immune response that can progress to cause widespread vasodilation, fluid to leak out of the vascular space and microclots to form in small blood vessels, which leads to tissue hypoxia and organ failure.
Early identification, IV fluid administration and antibiotic administration are key to patient survival from severe sepsis. Many EMS systems are involved in sepsis alert programs to notify the hospital and streamline treatment similar to trauma, STEMIs and stroke systems.
For patients with suspected pneumonia, consider sepsis in patients with two or more of the following vital signs that suggest systemic inflammatory response syndrome (SIRS):
- Pulse above 90
- Respiratory rate above 20
- Temperature above 38C (101F) or or below 36C (97F)
In addition to vital signs and physical exam, capnography has been shown to determine the severity of sepsis and predict mortality in patients with sepsis . Tissue hypoxia leads to anaerobic metabolism, which causes metabolic acidosis. As the patient’s respiratory rate increases to compensate for metabolic acidosis, excess CO2 is eliminated.
Normal end-tidal CO2 level is between 35 and 45 mm Hg. A study 201 adult patients in Orlando found that abnormal ETCO2 (above 45 mm Hg or below 35 mm Hg) in patients who meet SIRS criteria (from all causes) had a mortality rate six and a half times higher than those with normal ETCO2 levels. The authors also concluded that a persistent ETCO2 reading below 25 mm Hg correlated with an lactate level above 4 mmol/L, which is a blood test used to detect metabolic acidosis and organ dysfunction from severe sepsis .
For pneumonia patients, an abnormal ETCO2 level identifies patients who are at high risk for decompensation. In addition to managing respiratory problems associated with pneumonia, administer IV fluid boluses (20 to 30 ml/kg) to patients with suspected sepsis, even if they are not hypotensive. Abnormal ETCO2 with pneumonia also identifies pneumonia patients who should receive an urgent triage assignment in the emergency department.
A limitation to using capnography to detect sepsis is that patients with pneumonia may have an abnormal baseline ETCO2, especially if they have COPD (COPD patients were excluded from the Orlando study) . Consider the patient’s history and whether the capnogram has a shark-fin appearance when when using capnography to assess pneumonia patients who may have sepsis.
For pneumonia patients in respiratory failure, capnography should be used with caution to guide assisted ventilation rate. While waveform capnography has been used to avoid hyperventilation in intubated head injured patients, the ETCO2 of septic patients with pneumonia may be low before assisted ventilation [5,6]. Titrating assisted ventilation rate to the normal range of 35 to 45 mm Hg in pneumonia patients with sepsis may cause hypoventilation. Use feedback from capnography to ventilate pneumonia patients at 10 to 12 breaths per minute, but not to titrate a normal ETCO2 level.
EMS recognition and treatment of pneumonia and sepsis can have a significant effect on patient outcomes. Use history, physical exam and monitoring tools to identify pneumonia and sepsis, to guide treatment decisions and assess response to treatment.
1. Kamangar N, Harrington A, Byrd R. Bacterial pneumonia. Medscape. 2015, October 8. Retrieved from: http://emedicine.medscape.com/article/300157-overview
2. American Lung Association. Trends in pneumonia and influenza morbidity and mortality. Epidemiology and Statistics Unit Research and Healthcare Education Division (2015, November). Retrieved from: http://www.lung.org/assets/documents/research/pi-trend-report.pdf
3. Swaminathan A, Varkey B, Stearns D, Varkey A. Aspiration pneumonitis and pneumonia. Mediscape. 2016, July 1. Retrieved from: http://emedicine.medscape.com/article/296198-overview#a3
4. Cosentini R, Brambilla AM, Aliberti S, et al. Helmet continuous positive airway pressure vs. oxygen therapy to improve oxygenation in community-acquired pneumonia: A randomized, controlled trial. Chest. 2010; 138:114–120.
5. Hunter C, Silvestri S, Dean M, Falk J,Papa L. End-tidal carbon dioxide is associated with mortality and lactate in patients with suspected sepsis. American Journal of Emergency Medicine, 2013, 31(1), 64-71.
Davis DP, Dunford JV, Ochs M, et al. The use of quantitative end-tidal capnometry to avoid inadvertent severe hyperventilation in patients with head injury after paramedic rapid sequence intubation. Journal of Trauma 2004; 56(4):808-814.
This article was originally posted Aug. 15, 2016. It has been updated.