ACUTE HYPOXEMIA on Night FLOAT

Dr. Koprowski presented a night float cross cover case of acute hypoxemia in a patient with history of PVD and ILD, admitted for hematochezia, s/p colonoscopy which revealed pan colitis.

If you just received sign out about this patient what would you do?

Collectively we decided that a patient with a new oxygen requirement warrants bedside assessment (sooner than later).

How would you work this up?

Hunter mentioned approaching this problem using the “dyspnea pyramid,” (See Below)

dyspnea pyramid.JPG

When approached with a patient with new hypoxemia: always check an ABG and CXR

Additional work up based on clinical hx/exam

This patient’s vitals were notable for RR of 20-30 and SpO2 89-92% on 6 L NC (new since colonoscopy)

Exam notable for no increased work of breathing, RRR, no murmurs, abdominal distention, diffuse tenderness to palpation, rebounding, guarding, hypoactive bowel sounds, cool and mottled extremities.

Labs: notable for ABG: 7.39/33/74/20 CMP with AGMA (gap 22), lactate 5

Based on this information, we could re-frame this patient as an elderly man with PVD and acute hypoxemia in the setting of an acute abdomen and lactic acidosis.

With this problem representation, what is highest on your differential/a not miss diagnosis?

Did you consider acute mesenteric ischemia (if so like this blog).

Dr. Koprowski was concerned for acute mesenteric ischemia and as such he called a surgical consult and ordered a CTA at the same time. The general surgery resident who evaluated this patient agreed with the concerning exam, but ultimately the decision was made to hold off on exploratory laparotomy (definitive treatment for acute mesenteric ischemia) and to follow serial abdominal exams and lactates as the CTA was notable only for bowel wall edema. His clinical status worsened in the morning and he ultimately passed away from presumed mesenteric ischemia.

Acute MEsenteric ischemia, Take Home Points:

1) Acute mesenteric ischemia can be challenging to diagnose due to non-specific findings. A high clinical suspicion is necessary.

2) Though labs and imaging can help make the diagnosis, they are imperfect.

3) Most patients with acute mesenteric ischemia will have an elevated lactate and positive findings on CTA (which is considered the gold standard based on ACR appropriateness criteria).

4) Serial lactates do not correlate well with bowel necrosis (The value of Serial Lactate Measurements in Predicting the Extent of Ischemic Bowel and Outcome of Patients Suffering Acute Mesenteric Ischemia, J Gastrointest Surg (2015) 19: 751-755 https://link.springer.com/content/pdf/10.1007%2Fs11605-015-2752-0.pdf

5) Do not let your clinical judgement be swayed by one discordant piece of data.

For further details on acute mesenteric ischemia read NEJM review article cited below:

https://www-nejm-org.liboff.ohsu.edu/doi/pdf/10.1056/NEJMra1503884?articleTools=true