WIDI - C15) Worsening hypoxia after hospitalization for severe burn injuries

C15) Worsening hypoxia after hospitalization for severe burn injuries

Review the Learning Outcomes, Hx, PE and Labs, and begin the module with your Provisional Diagnosis. Keep hitting "Next" to move through the module.

Learning Outcomes

Articulate your relationship with the consulting diagnostic radiologists in the evaluation of a patient with hypoxia.
Review the DDx considerations in a patient with hypoxia.
Identify the spectrum of imaging findings in appropriate modalities for evaluating a patient with hypoxia.

History

A 32-year-old female presented five days ago with 50% body surface area burns resulting in inhalational burn injury and bilateral lower extremity circumferential burns requiring escharotomies. She was intubated and subsequently had a tracheostomy implanted. She now is developing worsening hypoxia.

Physical Exam

BP: 123/79, HR 92, RR 104, Temp 36.7, O2 saturation 87%. CV: No pitting edema in legs. Normal S1/S2, no murmurs, rubs, or gallops. No jugular venous distension. Pulmonary: diffuse crackles.

Labs

WBC: 7.0 x 10^9L (nl: 4.5 x 10^9L - 11 x 10^9L); PaO2: 50 mmHg; FiO2: 0.4; BNP: 15pg/mL (nL: <100).

Provisional Diagnosis

Select the Dx you believe is most appropriate

Pneumonia

Acute respiratory distress syndrome

Decompensated congestive heart failure

Acute respiratory distress syndrome is the most likely diagnosis considering the presence of a clinical insult (burns) with subsequent respiratory decline. Pneumonia is less likely considering the lack of fever and normal WBC count. Decompensated CHF is less likely considering the normal BNP and unremarkable cardiovascular physical exam.

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Potential Acuity

What is your assessment of the likely acuity for this patient?

Emergent (immediate plan required)

Urgent (plan required within 4 hours)

Routine

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The patient requires urgent workup for her hypoxic respiratory failure.

First Imaging Study

What is the first imaging study you will order?

Chest X-ray

Chest CT

Thoracic ultrasound

The chest X-ray is a good initial test for patients with respiratory decompensation. In this case, it may also detect a drainable pleural effusion or pneumothorax.

View ACR Appropriateness Criteria

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Pertinent Imaging Observations

Click on the links below to view images from the study, and assess these key findings as best you can.

AP chest x-ray

What best describes the findings on the Chest X-ray?

Cardiomegaly

Pulmonary edema in right hemithorax

Bilateral pulmonary edema

The chest x-ray demonstrates diffuse, bilateral coalescent opacities representing alveolar infiltrates with a normal heart size, consistent with ARDS.

View Report

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Second Imaging Study

What is the next imaging study you will order?

Chest CT

Thoracic ultrasound

None

The clinical presentation and chest x-ray shows are consistent with ARDS. Therefore, no further imaging is required. A pleural ultrasound can be performed in place of CT to detect the presence of pleural effusions if there is a high clinical suspicion.

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What is your Diagnosis now that you have seen the imaging results?

Mild ARDS

Moderate ARDS

Severe ARDS

The patient has moderate ARDS as the PaO2/FiO2 ratio is 125 (PAO2 ratios – Mild ARDS: 200-300, Moderate ARDS: 100-200, Severe ARDS: <100).

Current Acuity

Initially, you selected and we suggested acuity.

Has your concern for this patient changed?

Emergent (immediate plan required)

Urgent (plan required within 4 hours)

Routine

This patient urgently requires respiratory support escalation prior to any further decompensation.

Assessment and Plan

Please provide your assessment and plan for this patient

Worsening hypoxic respiratory failure following severe burn injury. Imaging and labs are consistent with moderate ARDS. The patient will require increased respiratory support with judicious up-titration of FiO2 and PEEP.

Lessons Learned:
- ARDS results from an insult causing alveolar injury, leading to increased alveolar permeability and protein and cell rich exudate infiltration of the alveoli.
- Chest x-ray can show “white out” of one of both lungs secondary to diffuse, coalescent airspace opacities from alveolar filling.
- Unlike CHF which can have similar findings, the heart size is normal in ARDS.
- This case describes the exudative phase of ARDS. The proliferative phase occurs later and is often characterized by chronic pulmonary fibrosis.

Socioeconomic Factors: ARDS can be diagnosed with clinical findings, labs, and X-ray. A pleural ultrasound can be used in place of CT to detect the presence of pleural effusions if there is a high clinical suspicion. This reduces radiation exposure and is particularly useful where CT is not readily available.

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