Critical Care Nursing Theory. Pneumonia. - Pneumonia is an acute infection of the pulmonary parenchyma

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1 - is an acute infection of the pulmonary parenchyma - is a common infection encountered by critical care nurses when it complicates the course of a serious illness or leads to acute respiratory distress. - The mortality rate climbs to 40% in those requiring admission to the intensive care unit (ICU) and elderly patients (older than 65 years of age) died of pneumonia at a significantly higher rate - Patients with severe community acquired pneumonia( CAP) require admission to the ICU. - Hospital-acquired (nosocomial) pneumonia (HAP) is defined as pneumonia occurring more than 48 hours after admission, which excludes infection that is incubating at the time of admission. - Types of hospital acquired pneumonia - Early-onset HAP occurs within 2 to 5 days of hospitalization, - Late-onset HAP occurs after 5 days of hospitalization. - Severe HAP may occur in the ICU, with patients receiving mechanical ventilation being at the greatest risk, or it may precipitate admission to the ICU. - The incidence of HAP is increased by 6- to 20-fold in patients receiving mechanical ventilation. - HAP independently contributes to mortality in critically ill patients; the attributable mortality rate is 11% to 33%. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 1

2 Etiology - Bacteria, viruses, mycoplasmas, other infectious agents such as fungi, and foreign material can all cause pneumonia. Etiology of CAP - Gram-positive organisms predominate in CAP, Streptococcus pneumoniae (pneumococcus) is the most common cause of CAP and also the most frequent cause of mortality in CAP. - Drug-resistant S. pneumoniae is frequently seen in individuals older than 65 years of age. - Other pathogens that should be considered in severe CAP requiring admission to the ICU include Haemophilus influenzae, Staphylococcus aureus, Mycobacterium tuberculosis, respiratory viruses, and endemic fungi. Etiology of HAP - Enteric gram- negative bacilli predominate in HAP. The enteric gramnegative bacilli and S. aureus (grampositive) are the most frequently identified organisms in HAP. - More than one organism may be identified in over 30% of patients with HAP, and HAP is frequently polymicrobial. - Polymicrobial HAP is particularly common (>50%) in patients receiving mechanical ventilation (ventilator-associated pneumonia). - Highly resistant gramnegative organisms (e.g., Pseudomonas aeruginosa, Acinetobacter species) and methicillin-resistant S. aureus are frequently seen in late-onset HAP but may occur in early-onset HAP in patients with risk factors for these pathogens. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 2

3 The spectrum of potential pathogens can be defined by assessment of a variety of factors, including :- Pathophysiology 1- The severity of the pneumonia, 2- Presence of comorbidities, 3- Prior therapy (including antibiotics), 4- Length of hospitalization. - is an inflammatory response to inhaled or aspirated foreign material or the uncontrolled multiplication of microorganisms invading the lower respiratory tract. - This response results in the accumulation of neutrophils and other effector cells in the peripheral bronchi and alveolar spaces. - The pathogenesis of bacterial HAP is depicted in the theoretical model postulated by the Centers for Disease Control and Prevention - The body s defense system, which includes anatomical, mechanical, humoral, and cellular defenses, is designed to repel and remove organisms entering the respiratory tract. - Many systemic diseases increase the patient s risk of pneumonia by altering the respiratory defense mechanism. - develops when normal pulmonary defense mechanisms are either impaired or overwhelmed, allowing microorganisms to multiply rapidly. - Pathogens may enter the lower respiratory tract and cause pneumonia in four ways: 1- Aspiration, 2- Inhalation, 3- Hematogenous spread from a distant site, 4- Translocation. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 3

4 1- Aspiration of microorganisms from the oropharynx. - Aspiration occurs frequently (>45% of the time) in healthy individuals while they sleep. - The risk of clinically significant aspiration is increased in:- - Patients with a depressed level of consciousness or dysphagia; - Those who have endotracheal or enteral tubes; - Those receiving enteral feedings. - For example, aspiration occurs more often (>70% of the time) and more extensively in patients with a depressed level of consciousness. 2- Inhalation of bacteria-laden aerosols from contaminated respiratory equipment. - Inhalation is an effective entry mechanism for Legionella species, M. tuberculosis, certain viruses, and fungi. 3- Hematogenous spread may be an effective mechanism; - The pulmonary circulation provides a potential portal of entry for microbes. - The pulmonary capillaries form a dense network in the walls of the alveoli that is ideal for gas exchange. - Hematogenous microbes from distant sites of infection can migrate through this network and cause pneumonia. - ( can also cause bacteremia. Secondary bacteremia after pneumonia has been reported in 6% to 20% of pneumonia cases.) Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 4

5 4- Translocation of bacterial toxins from the gut lumen to the mesenteric lymph nodes and eventually to the lungs - It may possibly cause bacterial pneumonia. However, translocation has not yet been confirmed as a pathophysiological mechanism. - Colonization of the oropharynx and the stomach plays an important role in the pathophysiology of bacterial pneumonia.(colonization is the presence of microorganisms other than the normal flora in the absence of clinical evidence of infection.) - Gram-positive bacteria and anaerobic bacteria normally live in the oropharynx, and it is hypothesized that they occupy bacterial binding sites in the oropharyngeal mucosa. When normal oropharyngeal flora are destroyed, these binding sites are susceptible to colonization by pathogenic bacteria. - The gram-negative or pathogenic gram-positive organisms that have colonized the oropharynx are readily available for aspiration into the tracheobronchial tree. Risk factors associated with oropharyngeal colonization include - Previous antibiotic therapy, - Increased age, - Depressed level of consciousness, - Dental plaque, - Smoking, - Chronic diseases, such as chronic obstructive pulmonary disease (COPD), - Alcoholism, - Diabetes mellitus, - Malnutrition. - The stomach can serve as a reservoir for bacteria. This organ is normally sterile because of the bactericidal activity of hydrochloric acid. However, when gastric ph increases above normal (ph >4), microorganisms are able to multiply. - Gastric colonization increases retrograde colonization of the oropharynx Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 5

6 and increases the risk of pneumonia. Individuals at risk for gastric colonization include 1- The elderly; 2- Achlorhydria, 3- Ileus, 4- Upper gastrointestinal disease; 5- Antacids, 6- Histamine-2 antagonists, 7- Enteral feedings. Risk factors for HAP :- A- Host-Related Risk Factors 1- Increased age 2- Altered level of consciousness 3- Chronic obstructive pulmonary disease (COPD) 4- Severe illness 5- Malnutrition 6- Shock 7- Blunt trauma 8- Severe head trauma 9- Chest trauma 10- Smoking 11- Dental plaque B- Treatment-Related Risk Factors 1- Mechanical ventilation 2- Reintubation or self-extubation 3- Bronchoscopy 4- Nasogastric tube 5- Presence of intracranial pressure (ICP) monitor 6- Prior antibiotic therapy 7- Elevated gastric ph 8- Histamine type 2 receptor blockers 9- Antacid therapy 10- Enteral feedings 11- Head surgery 12- Upper abdominal or thoracic surgery Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 6

7 13- Supine position C- Infection Control Related Factors 1- Poor handwashing 2- Changing ventilator tubing less than every 48 hours Assessment History - Hemoptysis implies tissue necrosis and is more common with - pyogenic streptococcal pneumonia, - anaerobic lung abscesses, - S. aureus, - necrotizing gram-negative organisms, - invasive Aspergillus. - Extrapulmonary symptoms may indicate specific pathogens; (Diarrhea & abdominal discomfort indicate Legionella species, ) (Otitis media & pharyngitis indicate Mycoplasma pneumoniae ) - Historical information may also be extremely helpful in diagnosis of CAP and HAP. It is necessary to include information about contact with animals, especially birds, bats, rats, and rabbits, which can assist with the diagnosis of histoplasmosis, psittacosis, tularemia, and plague. - In addition, a complete history may assist in the differential diagnosis. Diseases that may mimic pneumonia include:- - Congestive heart failure, - Atelectasis, pulmonary - Thromboembolism, - Drug reactions, - Pulmonary hemorrhage, - Acute respiratory distress syndrome. - The clinical presentation in the older adult may vary somewhat from what Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 7

8 is typical in a younger person Clinical manifestation in the older patient - The usual symptoms (fever, chills, increased white blood count) may be absent. - Confusion and tachypnea are common presenting symptoms in older patients with pneumonia. - Other symptoms in the older patient include weakness, lethargy, failure to thrive, anorexia, abdominal pain, episodes of falling, incontinence, headache, delirium, and nonspecific deterioration. Physical Findings - Patients present with new-onset respiratory symptoms (e.g., cough, sputum production, dyspnea) that are usually accompanied by fever and chills. - A comprehensive cardiovascular and pulmonary assessment should be completed, with a focus on the major and minor criteria of pneumonia. - The nurse should assess for signs of hypoxemia (duskiness or cyanosis) and dyspnea (nasal flaring). - Inspection of the chest includes assessing respiratory pattern and respiratory rate, observing the patient s posture and work of breathing, and inspecting for the presence of intercostals retractions. - Percussion of the chest frequently reveals dullness with lobar pneumonia. - Auscultation of the chest reveals decreased breath sounds are heard fine early crackles (formerly called rales) or bronchial breath sounds are heard over the area of consolidation. Diagnostic Studies - The diagnostic evaluation must be performed rapidly to prevent delays in initiation of antibiotic therapy. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 8

9 - All patients should have a chest radiograph (posteroanterior and lateral views) to identify both the presence and location of infiltrates. The chest radiograph is helpful in differentiating pneumonia from other conditions and identifying severe pneumonia, which is indicated by the presence of multilobular, rapidly spreading or cavitary infiltrates. - The value of examining lower respiratory secretions with Gram s stain and culturing sputum is controversial. it is not recommend routine use of Gram s stain and sputum culture and advises that results must be interpreted cautiously.however, the Infectious Disease Society of America (IDSA) recommends routine Gram s stain and culture of deepcough specimens. - Lower respiratory secretions can be easily obtained in intubated patients using endotracheal aspiration. - Nonquantitative endotracheal aspiration cultures may assist in excluding certain pathogens and may be helpful in modifying initial empirical treatment. - Routine use of quantitative invasive diagnostic techniques (bronchoscopy with protected specimen brush [PSB] or bronchoalveolar lavage [BAL]) in severe pneumonia is not recommended - Current guidelines suggest that BAL or PSB be used only in selected circumstances, such as in nonresponse to:- 1- Antimicrobial therapy, 2- Immunosuppression, 3- Suspected tuberculosis in the absence of a productive cough, 4- with suspected neoplasm or foreign body, 5- Conditions that require lung biopsy. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 9

10 Management Antibiotic Therapy - Patients should initially be treated empirically, based on the severity of disease and the likely pathogens. Initial therapy should be instituted rapidly. - Initial therapy should not be changed within the first 48 to 72 hours unless progressive deterioration is evident or initial microbiological (blood or respiratory) cultures indicate a need to modify therapy. Factors to consider when determining the duration of therapy include 1- Concurrent illness, 2- Bacteremia, 3- Severity of pneumonia at the onset of antibiotic therapy, 4- Infecting pathogen(s), 5- Rapidity of clinical response. Recommended duration of therapy is - 7 to 10 days for S. aureus or H. influenzae; - 10 to 14 days for M. pneumoniae and C. pneumoniae; - 14 to 21 days for P. aeruginosa and Acinetobacter, multilobar involvement, malnutrition, or a necrotizing gram-negative bacillus. Supportive Therapy - Oxygen therapy is required to maintain adequate gas exchange. - Mechanical ventilation to correct hypoxemia is frequently required in both severe CAP and HAP. - Humidified oxygen should be administered by mask or intubation to promote ciliary movement Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 11

11 Prevention - Primary measures to prevent CAP include the use of influenza and pneumococcal vaccines. - All immunocompetent patients 65 years of age or older should receive the pneumococcal vaccine. - People 65 years of age and older should receive both the pneumococcal vaccine (a one-time vaccination) and yearly influenza vaccines. - In addition, individuals 64 years of age or younger should be immunized if they have chronic illnesses, such as cardiovascular disease, chronic pulmonary disease (COPD, but not asthma), diabetes mellitus, alcoholism, chronic liver disease, cerebrospinal fluid leaks, and functional or anatomic asplenia; or live in special social settings, such as long-term care facilities. - Influenza vaccine is recommends for three target groups: - Persons at a high risk of influenza complications, - Persons who may transmit influenza to high-risk patients (e.g., health care workers); - Any person who wishes to decrease the chance of becoming infected with influenza. High-risk patients include - Individuals older than 65 years of age, - Residents of long-term care facilities, - Patients with chronic cardiovascular or pulmonary disease, - Patients who required regular medical care or hospitalization during the preceding year, - Pregnant women in the second or third trimester during influenza season. - Smoking cessation, particularly in patients who have previously had pneumonia, because cigarette smoking is a risk factor for both HAP and CAP pneumonia, education the cornerstone of an effective infection control program and the prevention of HAP. Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 11

12 - Comprehensive guidelines on the prevention of HAP World Wide Web access to the CDC guidelines is available at Dr Abdul-Monim Batiha - Assistant Professor Of Critical Care Nursing 12