Is it always necessary to perform an arterial blood gas after a blunt trauma?

   Clinical Scenario

A 53 year old man is involved in a motor vehicle crash. He refers a moderate thorax and abdominal pain. No head injury, the helmet is not broken, the patient remembers the accident. Systolic blood pression is 120/80 mmHg, respiratory rate is 24, saturation is 100%, he has abrasions over the torso and right thorax and flank, no wounds. The eFAST shows a normal pleural sliding, and no signs of intraperitoneal blood.

 The institutional blunt trauma protocol requires an arterial blood gas (ABG) and serum lactate (SL), than is obtained a CT of the chest abdomen and pelvis. 

After 15 minutes, the patient returns to the ED, TC is negative, the patient feels better, the nurse says that the ABG is abnormal, pH is 7.5 and lactate level is 4. 

Do abnormal ABG and/or SL change disposition after a negative CT?  

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Septic Arthritis and Arthrocentesis

A 33 y/o male comes to the ED for fever, knee swelling and pain.
He has a history of joint surgery because of trauma, and prothesis, dating 4 years before.
He is HIV positive
He presents feverish (38°C), the left knee is swollen and hot.
WBC 34.000/μL, CRP 109 mg/L, PCT 0,05 ng/mL.
As we have seen in previous post, history, clinical examination and serum test are not useful to rule out or in a septic arthritis. It’s time to perform arthrocentesis: sWBC: 60x109, sLactate: 10 mmol/L


Are this findings useful?

Conclusion 

Although arthrocentesis is not a risk-free procedure, synovial fluid analysis is essential for the diagnosis. 

sWBC count has been studied in several trials but a significant heterogeneity was noted so it should not be used in isolation to rule in or rule out the diagnosis of septic arthritis, anyway it should augment the entire clinical evaluation.

Synovial lactate, instead, has consistently demonstrated desirable diagnostic properties to rule in septic arthritis using a threshold of >10 mmol ⁄ L. 

Bibliography 

C. R. Carpenter et al;

Evidence-based Diagnostics: Adult Septic Arthritis

Acad Emerg Med Aug 2011, vol 18 n 8. 

see previous...


Ilenia Spallino

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Intestinal Ischemia and Lactate

A 84 y/o woman comes accompained by relatives for abdominal pain.

She is oriented and cooperative, she suffers pain (NRS 10/10).
Abdomen is treatable, but very painful in the lower quadrants, you see green watering diarrhea, she has not fever.
Abdominal Radiograph shows air/fluid levels
WBC: 35000/μl PCR: 22 mg/L Lactate: 1,7


Can you rule out intestinal ischemia?

Conclusion 

The performance of lactate and other serological markers is disappointing and not particularly helpful to rule out intestinal ischemia.

Bibliography 

NJ Evennett, MS Petrov, A Mittal, JA Windsor

Systematic Review and Pooled Estimates for the Diagnostic Accuracy of Serological Markers for Intestinal Ischemia

World J Surg (2009) 33:1374–1383 

Ilenia Spallino

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