Pulm Flashcards
What is alveolar hypoventilation?
Low PaO2, high PaCO2 (respiratory acidosis)
Etiology: pulmonary/thoracic diseases (COPD, OSA, obesity hypoventilation, scoliosis), neuromuscular diseases (MG, Lambert Eaton, Guillain Barre), drug-induced hypoventilation (anesthetics, narcotics, sedatives), primary CNS dysfunction (brainstem lesion, infection, stroke)
Normal Aa gradient (normal is less than 15)
What is VQ mismatch?
Etiology: atelectasis, pleural effusion, pulmonary edema, pulmonary embolism
Low PaCO2 (respiratory alkalosis) due to compensatory tachypnea
Elevated Aa gradient
What is delayed emergency from anesthesia?
Failure to return to consciousness w/in expected window of last administration of an anesthetic or adjuvant agent (typically 30-60m)
Etiology: drug effect, metabolic disorder, neurologic disorder
Presentation: respiratory failure (low pH, elevated pCO2, low pO2), bradypnea, bradycardia
Tx: ventilatory support
What is aspiration pneumonia?
Delayed in onset
Pathophys: lung parenchyma infection, aspiration of upper airway or stomach microbes (anaerobes) that colonize oropharyngeal secretions
Presentation: present days after aspiration event, fever, cough, foul-smelling/increased sputum, can progress to abscess; concurrent periodontal disease
CXR: infiltrate in dependent lung segment (classically RLL)
Mgmt: abx (clinda or beta lactam and beta lactamase inhibitor)
What is aspiration pneumonitis?
More acute in onset
An acute lung injury due to aspiration of acidic and sterile stomach contents.
Pathophys: lung parenchyma inflammation, aspiration of gastric acid with direct tissue injury
Presentation: present hours after aspiration event, range from no sxs to non-productive cough, decreased O2, respiratory distress
CXR: infiltrates (one or both lower lobes) resolve w/o abx
Tx: supportive (no abx)
What is atelectasis?
Lobar or segmental collapse of the lung that causes decreased lung volume
Etiology: due to mucus plugging
Pathophys: airway obstruction creates distal air trapping in alveoli, trapped air diffuses into blood stream, b/c no additional air can enter obstructed airway the alveoli become devoid of matter and collapse; to occupy vacated space, mediastinal structures are pulled TOWARD atelectasis
Common postop complication - results from shallow breathing and weak cough due to pain; common on POD2-3 following abdominal or thoracoabdominal surgery
Presentation: dyspnea, tachypnea, tachycardia
Lung exam: dullness to percussion and absence of breath sounds
CXR: opacification, w/ mediastinal shifting toward side of opacification, rib space narrowing
Tx: chest physiotherapy to prevent mucus plug (small), bronchoscopy to remove mucus plug (large); incentive spirometry for postop cases
What is post-operative atelectasis?
Impaired cough and shallow breathing
Due to airway obstruction from retained airway secretion, decreased lung compliance, postoperative pain, and medications that interfere with deep breathing
Present on POD2-3 from abd/thoracoabd surgery
high pH, low pO2, low pCO2
Tx: IS
What are postoperative pulmonary complications?
Complications: atelectasis, infection (pneumonia), bronchospasm, exacerbation of chronic lung disease, prolonged mechanical ventilation
RF: age >50, emergency surgery or surgery duration >3h, HF, COPD, poor general health
Preop strategies to reduce risk: smoking cessation at least 8w prior to surgery, sx ctrl of COPD (eg preop glucocorticoids if not well controlled), tx of any respiratory infections prior to surgery, pt education for lung expansion maneuvers (eg chest physical therapy, coughing, deep breathing exercises, incentive spirometry)
Postop strategies: incentive spirometry, deep breathing exercises, epidural analgesia instead of parenteral opioids, continuous airway pressure
What is a diaphragmatic hernia?
More common on L side b/c the R side tends to be protected by the liver.
Presentation: respiratory distress, deviation of mediastinal contents to opposite side
CXR: elevation of hemidiaphragm on CXR, nasogastric tube in pulmonary cavity*
What is a bronchogenic cyst?
Benign
Usually found in the middle mediastinum
Dx: CT scan
What is a thymoma?
Common in young male or female, 20% have myasthenia gravis, also assoc. with pemphigus
Usually found in the anterior mediastinum
Presentation: chest heaviness or discomfort; hoarseness, Horner’s syndrome, and facial and upper extremity edema may occur when tumors invade locally
What is a neurogenic tumor?
Located in the posterior mediastinum
Includes: meningocele, enteric cysts, lymphomas, diaphragmatic hernias, esophageal tumors, aortic aneurysms
Dx: MRI
What is a complicated parapneumonic effusion/empyema?
Caused by bacterial invasion of pleural space
Pleural fluid - exudative: low pH <7.2, low glucose <60, high protein, WBC >50k,
Pleural fluid gram stain and culture: positive
CXR: loculation (walled-off pleural fluid)
Tx: abx + drainage (chest tube)
What is an uncomplicated parapneumonic effusion?
Etiology: sterile exudate in pleural space
Pleural fluid: high pH >7.2, high glucose >60, WBC <50k
Pleural fluid gram stain and culture: negative
Tx: abx
What is spontaneous pneumothorax?
Assoc. features: primary - no preceding event or lung disease; Marfan, smoking, thoracic endometriosis, tall thin young men; secondary - underlying lung disease (eg COPD, cystic fibrosis; rupture of alveolar blebs is common)
Signs and sxs: chest pain, dyspnea, decreased breath sounds, decreased chest movement, ipsilateral hyperresonance to percussion
Dx: CXR
Imaging: absent lung marking, visceral pleural line
Mgmt: small (<2cm) - obs and supplemental O2 which enhances speed of resorption;
larger and stable - needle aspiration (2nd or 3rd ICS in midclavicular line or 5th ICS in mid or anterior axillary line)
hemodynamically unstable- chest tube/tube thoracostomy
What is tension pneumothorax?
Complication of subclavian central venous catheter placement
Assoc. features: life-threatening, often due to trauma or mechanical ventilation; rapid-onset dyspnea, tachycardia, tachypnea, hypotension, and distension of neck veins
Signs and sxs: same as spontaneous w/ HD instability, tracheal deviation away from affected side
High intrathoracic pressure compresses vena cava and impedes cardiac venous return resulting in decreased CO and hypotension
Imaging: same as spontaneous w/ contralateral mediastinal shift, ipsilateral hemi-diaphragm flattening
Mgmt: urgent needle decompression (needle thoracostomy) to prevent cardiovascular collapse followed by chest tube placement (tube thoracostomy) for definitive pneumothorax management
What is a pulmonary contusion?
Results in intra-alveolar hemorrhage and edema, complicates 35% of cases of blunt thoracic trauma
Clinical features: present <24h after blunt thoracic trauma; tachypnea, tachycardia, hypoxia
Dx: rales or decreased breath sounds, CT scan (most sensitive) or CXR w/ patchy, diffuse alveolar infiltrate not restricted by anatomical borders
Mgmt: pain control, pulmonary hygiene (eg nebulizer treatment, chest PT, supplemental O2 and ventilatory support
What is a massive PE?
PE complicated by hypotension and/or acute right heart strain.
[acute RH strain: JVD, R BBB]
Presentation: dyspnea, pleuritic chest pain, syncope, JVD, right bundle branch block
Dx: CT pulmonary angiography
Tx: respiratory and HD support, fibrinolysis (if no surgery w/in 10 preceding days)
An acute massive PE can cause abrupt increases in RA pressure to >10 and PA pressure >40. This can lead to decreased venous return to the LA, decreased CO, hypotension, and obstructive shock.
What is flail chest?
Pathophys: greater than/= 3 contiguous ribs fractured in greater than/= 2 locations –> flail chest segment
Findings: paradoxical chest wall motion w/ respiration, chest pain, tachypnea, rapid shallow breaths
CXR: rib fractures +/- contusion/hemothorax
Mgmt: pain control for uncomplicated rib fracture, supplemental O2, positive pressure ventilation (+/- chest tube) for flail chest/if respiratory failure
What is septic shock?
Presentation: fever, tachycardia, hypotension, poor urine output
Mgmt: securing airway, restoring adequate tissue perfusion through IV 0.9% saline (crystalloid) prior to administration of vasopressors, identifying underlying infection
Crystalloid should be given as IV boluses (500-1000ml) to improve SBP >90
What is a thermal burn?
Thermal injury to upper airway = burns on face, singeing of eyebrows, oropharyngeal inflammation/blistering, oropharyngeal carbon deposits, carbonaceous sputum, stridor, carboxyhemoglobin level >10%, history of confinement in a burning building
Presence of greater than/= 1 of these indicators warrants early intubation to prevent upper airway obstruction by edema
What is tracheobronchial rupture?
Secondary to blunt thoracic trauma
R main bronchus is most commonly injured
Presentation: pneumomediastinum and subcutaneous emphysema (palpable creptius below the skin)
XR: persistent pneumothorax despite chest tube placement and pneumomediastinum
Dx: high resolution CT scan, bronchoscopy, or surgical exploration
Tx: operative repair
What is asthma exacerbated respiratory disease?
Non-IgE mediated reaction resulting from aspirin-induded prostaglandin/leukotriene misbalance; increased production of pro-inflammatory leukotrienes
Seen in pts with hx of asthma or chronic rhinosinusitis w/ nasal polyposis
Presentation: bronchospasms (cough, wheezing, chest tightness), nasal congestion following aspirin ingestion (30m to 3h later)
Tx: avoidance of NSAIDS, aspirin, desensitization if NSAIDS are required, use of leukotriene receptor antagonists (eg montelukast)
What is hypertrophic osteoarthropathy?
Presentation: clubbing, sudden onset joint arthropathy, and periostosis of long bones, and synovial joint effusions
Assoc. w/ lung cancer
Dx: CXR to r/o malignancy and/or other lung pathology
What is respiratory distress syndrome?
Caused by immature lungs and surfactant deficiency
Inversely proportional to gestational age
RF: prematurity, maternal DM
Maternal hyperglycemia causes fetal hyperglycemia, which triggers fetal hyperinsulinism, which antagonizes cortisol and blocks maturation of sphingomyelin, a vital component of surfactant
Presentation: tachypnea, retractions, grunting, nasal flaring, and cyanosis at birth
XR: diffuse reticulogranular pattern (ground glass opacities), air bronchograms
Tx: corticosteroids, postnatal exogenous surfactant
What is clubbing?
Common causes: lung malignancies, CF, and R to L cardiac shunts
Due to entrapped megakaryocytes releasing PDGF and VEGF in distal fingertips
What is a bronchoscopy?
Initial procedure of choice in patients w/ hemoptysis (>600ml/24h or >100ml/h)
It can localize the bleeding site, provide suctioning ability to improve visualization, and include therapeutic interventions (eg balloon tamponade, electrocautery)
Asbestos
Asbestos exposure increases the risk of pulmonary fibrosis and malignancy.
Bronochogenic carcinoma is the most common malignancy diagnosed in pts exposed to asbestos.
Smoking acts synergistically w/ asbestos to further increase risk of lung cancer.
Pulmonary arterial hypertension.
LV systolic or diastolic dysfunction is a common cause of pulmonary HTN.
Tx: loop diuretics and ACE-i or ARBs.
Advanced dementia.
Leads to impaired swallowing and cough reflex.
Increased susceptibility to aspiration pneumonia.
What is an esophageal leiomyoma?
Located in the posterior mediastinum.
They are submucosal and usually asymptomatic.
They only produce symptoms when >5cm. Only large tumors should be removed.
Appearance of thymus on XR.
“Sail sign.”
Asthma + impending respiratory collapse.
Usually results in respiratory alkalosis (low CO2) due to hyperventilation.
Normal CO is bad = inability to maintain adequate ventilation, which is caused by respiratory muscle fatigue or severe air trapping and suggests impending respiratory collapse.
Treatment for community aquired pneumonia.
Presents w/ dyspnea, pleuritic chest pain, fever, productive cough
Focal increased breath sounds, crackles
Consolidative alveolar filling process on CXR
Dx of CAP requires presence of a lobar, interstitial, or cavitary infiltrate on CXR for confirmation. Clinical and physical findings are poor at predicting presence of pneumonia.
Sputum and blood cultures are typically NOT required in the OP setting as empiric oral abx are almost always curative.
Fluoroquinolone (eg moxi) or a beta lactam + macrolide (ceftriaxone + azithro)
Meds cover most common bacterial CAP organisms: s. pneumo, h. flu, legionella, and mycoplasma pneumoniae
Macrolide or doxycycline is needed to cover for atypical bacterial pathogens.
