Acute dyspnea

Respiratory system

- Acute causes:
  - Acute laryngopharyngitis; epiglottic and laryngeal edema;
  - Diphtheria
  - FB aspiration
  - GERD
  - Asthma
  - Toxic inhalation, , ARDS/shock, Pulmonary edema
  - Atelectasis
  - Pleural effusion
  - Pneumothorax
  - Diaphragmatic paralysis
  - PE, MI
  - Panic attack
  - Anaphylaxis
- Chronic causes
  - Laryngeal/tracheal tumor or nodes
  - Aortic aneurysm
  - Scarring of trachea from previous tracheostomy, prolonged endotracheal intubation, or trauma
  - Chronic bronchitis
  - Kyphoscoliosis
  - COPD
  - Bronchiectasis
  - Pneumoconiosis, Hypersensitivity pneumonitis (organic dust inhalation)
  - Viral pneumonitis
  - Pneumonia
  - ILD - Sarcoidosis, Rheumatoid arthritis, SLE, PSS, histiocytosis X, pulmonary vasculitides
  - Chronic eosinophilic pneumonia
  - Kyphoscoliosis
  - Obesity
  - Cystic fibrosis
  - TB
  - Coccidioidomycosis, histoplasmosis, MAI, CMV, PCP

Cardiovascular system

- CHF
- PE
- Pulmonary edema
- Mitral stenosis
- Aortic stenosis
- CHD
- Pericardial effusion, constrictive pericarditis
- Pulmonary HTN
- Anemia
- AV shunt

Drug-Induced

- ILD: amiodarone, beta-blockers, bleomycin, busulfan, chlorambucil, nitrosurea. melphalan, procarbazine, azathioprine, nitrofurantoin, cyclophosphamide, methotrexated, PCN, sulfonamides
- Pulmonary edema: heroin, methadone, HCTZ, propoxyphene, contrast media
- Asthma: NSAIDs, ASA, BB, cholinergic drugs, PCN, tartrazine.

Others: Anxiety, panic attack, hyperthyroidism, carcinoid syndrome, myasthenia gravis and other neuromuscular diseases, pregnancy, metabolic acidosis.

SHORTNESS OF BREATH

When called to see a Pt. with SOB...

- What are the patient's VS, including temp, RR, pulse ox?
- When did the SOB start?
- What was the reason for admission?
- Does the Pt. have COPD or is the patient getting oxygen?
- Order O2, albuterol, atrovent neb, ABG kit to bed side, resp. therapist.
- What is Anesthesia pgr no? Go and see Pt. immediately.

Major Causes of SOB

- Pulmonary: COPD, asthma
- Cardiovascular: CHF and PE
- Others: PTx, cardiac tamponade, FBAO, and anxiety

H&P:

- Check airway
- Check BP both arms (for any differential BP), pulse, RR, O2 sats, temp, color, capillary refill.
- Look at the Pt, mental status and ability to answer questions.
- Is the Pt able to talk in full sentences, or has signs of respiratory distress like, anxiety, diaphoresis, use of accessory muscle of resp, nasal flaring, audible wheeze, cyanosis, color?
- Review the chart.
  - Orthopnea, PND - CHF, MI
  - Acute, intermittent episodes of dyspnea are more likely to reflect episodes of myocardial ischemia, PE, or bronchospasm, while persistent dyspnea is typical of COPD, and ILD.
  - Platypnea - think L. atrial myxoma or hepatopulmonary synd.
  - Risk factors and co-morbidities, especially for CAD, PE, thyroid d/o, and occupational lung disease.
  - Think if the Pt. may have aspirated food or liquid...
  - In ESRD on HD, ask when was the last dialysis; if missed dialysis - possible fluid overload; also ask if the Pt. produces urine. Check if Cr elevated and bicarbonate is low - metabolic acidosis.
- Get an ECG and ABG if the Pt. looks sick.
- Check for pulsus paradoxus (but don't waste much time). If it is >10 mm Hg, consider the presence of COPD.
  - Normally SBP drops by 3 - 4 mm Hg on inspiration. >10 mm Hg drop indicates, pulsus paradoxus.
  - Check the BP for a paradoxical pulse. Cuff pressure is inflated >20 mm Hg of the palpable SBP. Deflate the cuff, slowly until the 1st Korotkoff sound is heard. This is the highest SBP during the respiratory cycle. However, this is heard only during expiration, and disappears during inspiration. Deflate the cuff pressure more, until Korotkoff sounds are heard in both inspiration and expiration. Measure the difference between the mmHg reading when Korokoff sounds were heard only during expiration from the mmHg reading when Korotkoff sound were heard in both inspiratory and expiratory phase of respiration. If the difference is >10 mm Hg, pulsus paradoxus is present.
- Check for central cyanosis
- Check for signs of anemia.
- Marked reduced respiratory rate is serious.
- Check for pattern of respiration (Cheyne-Stokes)
- Check for stigmata of liver disease.
- Check of clubbing of digits.
- Joint swelling and deformity as well as Raynaud's disease - collagen vascular disease.
- Check for symmetry of chest and movts with resp.
- Percussion dullness or hyper-resonance
- Listen for crackles, wheeze, and breath sounds on both side.
- Check JVD, listen for heart sounds, P2, ( S3, S4) gallops, murmurs, pericardial friction, rub, peripheral edema, tender and palpable liver,

Lab/Dxtic:

ABG, ECG, CXR, troponin, V/Q scan, D-dimer, and CT-Thx with IV contrast (check Cr. level - for need of mucomyst protocol)

- CXR: Prominent pulmonary vascular markings in the upper zones suggest pulmonary venous hypertension, while enlarged central pulmonary arteries suggest pulmonary artery HTN. Cardiomegaly suggest CM, VHD. B/L pleural effusion suggest CHF and some forms of collagen vascular disease. Unilateral pleural effusions may indicate malignancy and PE, but may also occur in CHF.
- CT of Tx with IV contrast for ILD and PE.
- TTE for Pt. with systolic dysfx, pulm. HTN, and VHD.

Management:

- Correct the underlying problem.
- O2 to keep sat >92%. Be cautious if the Pt has COPD and is a CO2 retainer. Remember the O2 sats tell you nothing about pH and PCO2. Do a ABG.
- For PE, look for predisposing causes.
  - Classic ECG pattern of S1Q3T3 may not be seen, more likely T-wave inversion in V1 - V4, RBBB, RAD, occasionally ST-elevation V - V3.
  - Often Pt is tachycardic, tachypneic, has sudden onset of SOB, has pleuritic CP.
  - If suspicion is high for PE, consider starting LMWH or heparin. Ensure Pt. has no h/o bleeding d/o, PUD, recent CVA, or surgery.
  - Obtain V/Q scan or spiral CT. Also, consider lower ext. Dopplers for DVT, and d-Dimer.
- For CHF, is the Pt vol overloaded? Raise the HOB. Administer Lasix 20 - 40 mg IV, and albuterol neb. Consider morphine or NTG. Assess adequacy of diuresis.
- For asthma and COPD, administer Albuterol, atrovent neb, q2 - 4h until stable. Consider IV corticosteroids, methylprednisolone (Solu-Medrol), 60 mg IV q6h, and ABX if needed.
- Acute resp failure is generally defined by ABG of PO2 <50 or PCO2 >50 with a pH <7.3 while breathing room air. Ensure the Pt has not received narcotics recently. If so, consider naloxone, 0.2 mg IV. Acute resp acidosis with a pH <7.2 usually requires mechanical ventilation.