Case Study
A rapid response event was activated by the bedside nurse for a patient who developed acute respiratory distress. Upon the arrival of the rapid response team, it was found that the patient was a 55-year-old male with a history of alcohol abuse, chronic obstructive pulmonary disease (COPD), congestive heart failure (most recent left ventricular ejection fraction 20%) who initially presented for evaluation of chest pain. Emergent cardiac catheterization was performed through the femoral artery, and two coronary stents were placed. Overnight, the patient developed increasing difficulty breathing associated with tachycardia.
Vital Signs
Temperature: 37.4 °F
Blood Pressure: 90/60 mmHg
Heart Rate: 120 beats per min – with sinus tachycardia on tele-monitor
Respiratory Rate: 35 breaths per min
Pulse Oximetry: 85% on room air, improved to 97% on 2 L oxygen
Focused History and Physical Examination
A middle-aged male who was visibly in distress was seen. Lungs and heart were clear on auscultation. However, the patient appeared dyspneic and was using accessory muscles of respiration. Abdominal examination was unremarkable, but inguinal examination showed bruising around the puncture site with associated swelling. The remaining examination was unremarkable.
Interventions
Based on the history and physical examination, the patient appeared to be in acute hypoxic respiratory failure. He was placed on 2 L of supplemental oxygen through a nasal cannula, and 1 L of IV fluid bolus was initiated. A cardiac monitor was attached. Stat chest X-ray, arterial blood gas, EKG, brain natriuretic peptide (BNP), troponin, and basic labs were ordered. The chest X-ray was negative for any acute infiltrates. Arterial blood gas showed a pH of 7.59, pCO2 of 22, and pO2 of 52, which was significant for alkalosis and hypoxemia. Basic labs showed hemoglobin 4.1 mg/dL. His other labs were unremarkable. Computed tomography (CT) angiography of chest, abdomen, and pelvis was ordered stat to assess for an occult bleed. The patient was given an urgent blood transfusion and admitted to the intensive care unit for closer monitoring. Interventional radiology was consulted to evaluate for possible embolization.
Final Diagnosis
Respiratory distress as an early feature of hemorrhagic shock and symptomatic anemia.
Tachypnea
The average breathing rate for an adult is 12-20 breaths per min. Tachypnea is defined as a breathing rate greater than 20 breaths per min. In contrast, dyspnea is the perception of an inability to breathe comfortably. Both these terms are often used interchangeably in the clinical setting. A wide variety of reasons can cause tachypnea. Clinicians must work through a comprehensive list of differentials to promptly identify the underlying cause and rule out life-threatening causes of tachypnea ( Table 17.1 ).
| Life-threatening causes of tachypnea | Common causes of tachypnea |
|---|---|
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Tachypnea is mediated through two different mechanisms. Pulmonary pathologies such as COPD, asthma, and congestive heart failure drive tachypnea by stimulating primary pulmonary mechanisms such as alveolar wall stretch and by activating lower airway receptors. Extrapulmonary factors drive tachypnea by stimulating medullary and carotid body chemoreceptors, the details of which can be found in Fig. 17.1 . A systematic approach is required when evaluating a patient with tachypnea.
- 1.
Pulmonary causes: The pulmonary system is the first organ system that should be evaluated in a tachypneic patient. Common causes include:
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Asthma/COPD: These patients usually present with difficulty breathing. Classic exam findings include wheezing and prolonged expiratory phase on auscultation. Chest X-ray is usually without infiltrates with hyper-inflated lungs and a flattened diaphragm ( Fig. 17.2 ).
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