ventillation interferes with mucociliary clearance (e.g., ability to cough) and positive pressure is damagin to normal ability to clear colonization, so VAP has an incidence as high as 5% / day in first few days on vent
Dx can be hard to establish because patients tend to have multiple countercurrent illnesses (e.g., CHF). Look for FEVER and/or rising WBC count OR NEW INFILTRATE on Chest Xray OR increased or different appearing PURULENT SECRETIONS from endotracheal tube
Sputum Culture is nearly WORTHLESS (because endotracheal tube colonization is frequently colonized). So from least accurate but easiest to most accurate but dangerous: (1) tracheal aspirate - suction cath into ET and aspirate contents below trachea when cath is past end of tube (contaminable from endotracheal tube), (2) Bronchoalveolar Lavage (BAL) - bronchoscope is deeper in longs (where there aren't organisms, but contaminable when passed through nasopharynx), (3) Protected Brush Specimen - tip of bronchoscope is covered when going through nasopharynx and uncovered when inside lungs, (4) Video-assisted Thorascopy (VAT) (scope through chest wall and sample of lun biopsied; allows biopsy without cutting open chest (thoracotomy)), (5) Open Lung biopsy - most accurate test for VAP, but greatest potential for morbidity and complication because of need for thoracotomy
Look out for
Diffuse subcutaneous emphysema (represents leakage of air into soft tissue of chest wall) -- causes include placement of chest tube but also include damage secondary to positive pressure ventillation from vent
Combine 3 drugs: (1) antipseudomonal beta-lactam: antipseud ceph (ceftazidime or cefepime) OR antipseu penicillin (piperacillin/tazobactam) OR carbapenem (imipenem, meropenen, or doripenem AND (2) Seond antipseudomonal agent = aminoglycoside (gentamicin, tobramycin or amikacin) AND MRSA agent (such as van or linezolid). THEN CHANGE THERAPY TO NARROW FOR PARTICULAR AGENT WHEN AGENT IDENTIFIED
Rare b/c aspiration pneumonia is usually promptly treated. Occurs ONLY WITH large-volume aspiration of oral/pharyngeal contents, usually with POOR DENTITION, who isn't adequately treated. Happens in the RIGHT UPPER LOBE WHEN LYING FLAT
Causes of Large-Volume Aspiration
stroke with loss of gag reflex, seizures, intoxication, endotraceal intubation.
Look for person with one of risk factors, presenting with chornic infection developing over several WEEKs with large-volume SPUTUM THAT IS FOUL SMELLING b/c of anaerobes. Weight loss is common
Dx Tests for lung abcess
Best initial: Chest X-ray (will see cavity, possibly with air-fluid level), MORE ACCURATE - Chest CT; ONLY LUNG BIOPSY can establish specific microbiologic etiology. SPUTUM IS WRONG IN ABSCESS (b/c everyone's has anaerobes from mouth flora)
Almost exclusively in untreated AIDS with CF 4 <200. Also occurs in chronically immunosuppressed patients, especially thos on LONG TERM HIGH DOSE STEROIDS
PCP Pneumonia Presentation
Patient with AIDS presenting with DYSPNEA on EXERTION, dry cough (severe), and high fever
PCP Pneumo DX Tests
Best initial: Chest X-ray (shows bilateral infilitrates) OR ABG looking for hypoxia or an increased A-a gradient. Additionally LDH levels are ALWAYS ELEVATED. Most Accurate Test: BAL. Sputum stain is often negative, but VERY SPECIFIC. If positive, no need for further testing. If negative Bronch is necessary as "best diagnostic test." DO NOT ANSWER PCP AS MOST LIKELY DX IF LDH IS NORMAL.
PCP Pneumo Chest Xray
Cannot distinguish from Mycoplasma, Chlamydophila, or viruses by xray alone. However, PCP IS MOST LIKELY DX in HIV patient with INFILTRATES.
PCP Pneumo TX
Best initial therapy (Both TX and Prophylaxis): TMP/SMX. ADD STEROIDS TO DECREASE MORTALITY if PCP is SEVER (severe = P02 <70 OR A-a gradient > 35). Atovaquone is alternative if TMP/SMX allergy or as alternative if PCP is mild (meaning only mild hypoxia). If toxicity from TMP/SMX (or atovaquone), can SWITCH to (1) Clindamycin AND primaquine or (2) pentamidine
TMP/SMX adverse effect
MOST COMMON IS RASH and BONE MARROW SUPRRESSON is 2nd MOST COMMON
Points about Switching
Primaquine is contraindicated in G6PD. Clindamycin and Primaquine have greater efficacy than Pentamidine. Pentamidine must be given intravenously for active infection.
Indicated in patients with AIDS and CD4 < 200: 1st line = TMP/SMX (which can cause Rash OR Neutropenia). 2nd Line = Atovaquone OR Dapsone. 3rd Line = Aerosolized Pentamidine (less efficacy than 2nd lines)
Prophylaxis for atypical mycobateria in AIDS
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