key: cord-0036737-lwbgc3il
authors: Khatib, Khalid; Dixit, Subhal; Chawla, Rajesh; Todi, Subhash
title: Severe Community-Acquired Pneumonia
date: 2019-09-28
journal: ICU Protocols
DOI: 10.1007/978-981-15-0898-1_12
sha: a50f468c9144166a7b58026a215e0f6cb847c9e5
doc_id: 36737
cord_uid: lwbgc3il

A 58-years-old male, smoker (8 pack-years) and having Diabetes mellitus and Hypertension for 8 years, presented to the ED with fever and acute dyspnoea for the last 48 h. On examination, respiratory rate was 34 breaths/min, blood pressure-150/96 mm Hg, heart rate-112/min, regular, and Oxygen saturation of 86% on 4L of oxygen by mask. He was conscious and oriented. His chest X-ray showed left lower zone consolidation.

3. Assess the volume status (invasive and/or non-invasive hemodynamic monitoring) and administer IV fluids and/or vasopressors as needed.

Step 2: Assess Severity of CAP and Risk Stratification 1 . Severity assessment: The severity of CAP is assessed according to the various severity scores e.g. Pneumonia severity index (PSI), CURB-65, CRB-65, 2007 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) criteria for ICU admission for CAP (a) Pneumonia severity index (PSI): It has moderate to good accuracy in predicting the 30 day mortality in patients with CAP. Points are given for age, gender, co-morbid illness, physical examination findings, ABG analysis, blood chemistry, hematocrit and chest X-ray findings and score is calculated. Patients are classified as PSI I to V according to their final score with mortality ranging from 0.1% to 27% respectively. It has superior ability to detect low risk patients. PSI I & II can be managed as an outpatient whereas IV and V needs hospitalisation (b) CURB-65: It consists of 5 core elements (new onset Confusion, Urea > 20 mg/ dl, RR > 30 bpm, SBP < 90 mmHg or DBP < 60 mmHg, Age 65 years or older, 1 point each for a total of 5). CURB 65 of 0 can be managed as outpatient, CURB 65 1&2 generally require ward treatment and a score of 3 or more warrants inpatient and aggressive treatment, usually in the ICU. It has superior ability to detect high risk patients. A simpler version of this score the CRB-65, does away with urea measurement without losing it effectiveness to detect high risk patients. Some studies have suggested an age group of ≥ 80 years (CRB-80) to have better predictability for mortality. (c) 2007 ATS/IDSA criteria for ICU admission for CAP: It consists of 2 major (invasive mechanical ventilation, septic shock requiring vasopressors) and 9 minor criteria (confusion, RR > 30 bpm, PaO 2 /FiO 2 ratio < 249, multilobar infiltrates, BUN>20 mg/dL, WBC < 4000/mm 3 , platelet count<1,000,000/ mm 3 , temperature < 36 °C, hypotension requiring fluid resuscitation). Presence of 1 major or 3 minor criterion requires admission to ICU. It has the ability to predict ICU admission with 84% sensitivity and 78% specificity.

The principles of therapy for severe CAP are:

1. Early initiation of antibiotic therapy even as the initial resuscitative measures are ongoing should be the aim as it improves mortality. Those patients of severe CAP admitted through the emergency department (ED) should receive the first dose of antibiotic in the ED itself. 2. Blood and sputum cultures should be sent for antibiotic sensitivity testing before starting antibiotics but this should not delay the initiation of antibiotic therapy. 3. The initial choice of antibiotic will depend on a detailed and in-depth history with particular emphasis on identifying etiology of CAP (see Table 12 .1) and whether the patient is at risk for infection with drug resistant organisms (see Table 12 .2). 4. The initial choices of antibiotics in patient with no risk factors are:

(a) A Beta-lactam/Beta lactamase inhibitor (Amoxicillin-clavulanate, Ampicillin-sulbactum, OR a cephalosporin (Cefuroxime, Cefotaxime, Ceftriaxone) plus a Macrolide (Azithromycin, Clarithromycin)/Doxycycline/ respiratory Fluoroquinolone (Levofloxacin, Moxifloxacin). OR (b) A Beta-lactam (Amoxicillin-clavulanate, Ampicillin-sulbactum, Cefuroxime, Cefotaxime, Ceftriaxone) plus Aztreonam (for patients with penicillin allergy). Step 4: Investigations

The following investigations are sent simultaneously with resuscitation and empirical antibiotic initiation (see Table 12 .3):

Step 5: Supportive Therapy 1. Severe CAP associated with septic shock and multi-organ dysfunction/failure should be treated according to appropriate Surviving Sepsis guidelines. 2. In patients with COPD or Bronchial asthma, aerosolised bronchodilators should be used as and when required, in adequate doses and frequency. 3. Non-invasive Ventilation (NIV): NIV is tried cautiously in patients with hypoxemia and increased work of breathing (respiratory distress), especially those with COPD or bronchial asthma. These patients are closely monitored and if no improvement is apparent after 2 h, may be intubated and mechanically ventilated. Patients with severe hypoxemia or bilateral/multilobar infiltrates and having respiratory distress should receive immediate invasive mechanical ventilation. is commonly seen -Lobar consolidation in the upper lobe is commonly seen in klebsiella pneumonia -Multilobar consolidation is commonly seen is legionella, severe pneumococcal or staphylococcal pneumonia Echocardiogram -To be done if patient has septic shock or IHD (continued) 4. Steroids: Patients with vasopressor resistant shock are given low dose intravenous steroids. Patients with COPD or Bronchial asthma on oral steroids are continued on equivalent intravenous doses of steroids. The routine use of corticosteroids as an adjunctive therapy for severe CAP with brisk inflammatory response has been suggested by some RCTs and meta-analyses but as per the latest guidelines, it is not recommended. Steroids should be used only in the presence of septic shock not responding to vasopressor therapy, as per the surviving sepsis guidelines. Avoid steroid in patients with Viral and Aspergillus pneumonia, Immunosuppressed host and Uncontrolled diabetic. 5. Patients with severe CAP should receive routine supportive ICU measures.

On institution of appropriate antibiotic therapy, improvement in clinical course of the patient is apparent within 3 days, as assessed clinically by Halm's clinical stability criteria [temperature ≤ 37.8 °C, heart rate ≤ 100 bpm, respiratory rate ≤ 24 bpm, SBP ≥90 mmHg, O 2 saturation ≥ 90%, or arterial O 2 tension ≥60 (on room air), normal mental status, and normal oral intake) or simplified ATS criteria [improvement in cough and dyspnea, absence of fever (>37.8 °C) for >8 h, normalisation of total leukocyte count by 10% from the previous day, and adequate oral intake]. An associated improvement in biomarkers (CRP reduction <50%, reduction in procalcitonin) will also act as a guide to response.

Patients who do not show the expected clinical response within the expected timeline are labelled as non-responders. The reasons for non-response may be:

1. Infection related causes:

(a) Treatment failure: It is defined as persistence /progression of pneumonia resulting in need for mechanical ventilation or development of septic shock. This may be early (within 72 h) or late (after 72 h). It may be due to various reasons as mentioned below: Step 7: Further Workup for Non-Responders

Fibreoptic Bronchoscopy with analysis of BAL

Endotracheal aspirate culture (preferably quantitative) and sensitivity

Anti-nuclear antibody, antineutrophil cytoplasmic antibody

Venous Doppler of lower limbs

Ultrasonography of the Chest/Computed tomography of the Chest-demonstrates presence of effusion, empyema or abscess and their localisation

The duration of therapy depends on the clinical response, organism involved, co-morbidities present, biomarker response and presence of complications

and generally for 7-10 days. Patient should be afebrile for 48-72 h, and should be clinically stable before discontinuation of therapy

The duration of antibiotics may be prolonged (upto 14 days) in slow responders, infections with Pseudomonas, Gram negative bacilli or Staphylococcus, presence of complications like lung abscess or empyema and presence of extra-pulmonary and metastatic infections (meningitis, endocarditis) secondary to the severe CAP

Key Preventive Measures Smoking cessation, Influenza and Pneumococcal Vaccination

and ATS/IDSA 2007 criteria for clinical stability in hospitalised patients with CAP are clinically equivalent and both can be used in clinical practice as well as in clinical research

The achievement of early clinical stabilization in CAP (≤4 days) is associated with improved outcomes, lower requirement for initial treatment modification or readmission

NRP may vary from a benign delay in recovery to life-threatening progressive pneumonia. A systematic approach to investigation and management is needed with consideration of both infectious and non-infectious causes

Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the american thoracic society and infectious diseases society of america

Early and close collaboration between emergency medicine and respiratory and critical care medicine teams is required to successfully decrease mortality for severe CAP

The use of corticosteroids in patients with severe CAP can reduce the time to clinical stability and the risk of treatment failure, and the administration of intravenous immunoglobulins can reinforce the immune response to infection

Effect of corticosteroids on treatment failure among hospitalized patients with severe communityacquired pneumonia and high inflammatory response a randomized clinical trial