A healthy young man comes to the ED after having been chased by the police. They say he ran for his life at least 1km after which they found him lying down, presumably unconscious. With all systems intact and stable vitals he's presumed to be faking (pseudocoma).
A quick glance in the ED reveals nothing new to refuse this theory - the patient has closed eyes and is totally resistant to pain stimulation but has all reflexes intact (eg. gag, cornea-) and with eyes forced open he's looking straight forwards (to contrast with eg. roving eye movements if true coma). ECG comes in normal.
The police officers are informed that patient can return to police station as soon as
blood results have been seen. And here they come...
With a hefty metabolic acidosis and lactate of 12,9 there's a minute of silence and doctors start thinking if there's a red herring in the room...
Could the patient be intoxicated after all?
Alcohols maybe?
He doesn't smell - but do all alcohols smell?
That's an anion gap of 18 - is it all explained by lactate?
With a presumed intoxicated patient fluids are ordered and patient is prepared for admission. Just that 45mins later the policemen come to let know that the patient is now awake and feeling well and ready to leave the ED with the officers. So a new blood gas (venous of course, who's sticking arteries these days anyways!) is drawn and voila;
All results normal... So the lactate acidosis turns out to be caused by strenuous physical exercise. Now howzaaat!
Learning points
Lactate can be very high after exercise! I remember a study where alpine ski-ers had 6-7 after coming down a slope and I've heard experienced clinicians state it may temporarily reach 20 after seizure). But you can even get disturbing pH levels from it!
Ethylene-glycol and methanol are odorless!
And my question to the audience: can I somehow calculate presumed anion gap from lactate levels, so that I can exclude other agents?
Elderly gentleman seeks the emergency department because of sudden dyspnea. He has no previous diagnosis of relevance such as COPD or heart failure. EMS notices crepitations on lung auscultation and treats patient with diuretics and CPAP with some relief. In the ED patient is still dyspneic and using accessory muscles for breathing but no clear crepitations are to be heard on auscultation and patient is not obviously obstructive. Stable vital signs, systolic blood pressure of 160mmHg.
Bedside chest x-ray is ordered but image result is not expected for a while. The ultrasound machine is turned on and the cardiac probe put on patient's thorax, revealing...
1. Heart, subxiphoid view
# Left > right ventricle => right strain and pulmonary embolism very unlikekly
# No pericardial effusion anteriorly, 2-3mm black line seen and assumed to be physiologically normal fluid
# Visually, decreased contractibility of left ventricle
2. Right pleura
Pleural effusion and several B-lines are clearly seen as the base of the lung reaches down, indicating right sided pulmonary edema
3. Left pleura
Great amounts of pleural effusion. No clots seen and thus no suspicion of blood. Multiple B-lines indicating left sided lung edema.
Same as right side; thus patient has massive, bilateral pulmonary edema.
The investigation was done in about 2 minutes.
The X-ray image arrives 45mins later
It shows enlarged heart with widened pulmonary veins and interstitial fluid bilaterally. Bilateral pleural effusion, more on left side. ProBNP arrives at 2500 with minimal Troponin elevation. Patient is treated as acute left sided heart failure and treated with CPAP and nitro infusion (SCAPE).
Discussion
Previously, ultrasound has been said to be impossible to use for evaluating lungs, after all "air is ultrasound's greatest enemy". Experimenting with this has shown that indirect signs can be seen such as A- and B- lines and as air is replaced with consolidations and edema, ultrasound will immediately pick this up. For pneumothorax and pleural effusion, pulmonary edema and consolidations (pneumonia or ARDS), ultrasound is becoming a first choice for quick bedside evaluation. Increasing amount of data is supporting this and in some emergency departments, bedside chest x-ray has been replaced by ultrasound as only CT has better sensitivity for most conditions of relevance in the ED.
Pneumothorax: Acad Emerg Med. 2005 Sep;12(9):844-9
“The sensitivity for chest radiography was 75.5% (95% CI = 61.7% to 86.2%) and the specificity was 100% (95% CI = 97.1% to 100%). The sensitivity for US was 98.1% (95% CI = 89.9% to 99.9%) and the specificity was 99.2% (95% CI = 95.6% to 99.9%)”
Pleural effusion, pulmonary edema, consolidation: Anesthesiology. 2004 Jan;100(1):9-15
“Auscultation had a diagnostic accuracy of 61% for pleural effusion, 36% for alveolar consolidation, and 55% for alveolar-interstitial syndrome. Bedside chest radiography had a diagnostic accuracy of 47% for pleural effusion, 75% for alveolar consolidation, and 72% for alveolar-interstitial syndrome. Lung ultrasonography had a diagnostic accuracy of 93% for pleural effusion, 97% for alveolar consolidation, and 95% for alveolar-interstitial syndrome. “
Let's summarize the data above:
Auscultation
Chest X-ray
Ultrasound
Pleural effusion
61%
47%
93%
Consolidation
36%
75%
97%
Pulmonary edema
55%
72%
95%
Pulmonary embolism
The story of ultrasound becomes only better and better. Here, ultrasound is compared with CT for diagnosis of pulmonary embolism - the condition every physician fears to miss. Chest. 2001 Dec;120(6):1977-83:
“The sensitivity of TS [transthoracic sonography] for detecting PEs was 80% (sensitivity of CT scanning, 82%), and the specificity of TS for detecting pulmonary lesions was 92%”
Volume status and heart - ultrasound for evaluation for shock
With ultrasound, a rough estimate of cardiac function and volume status (~vena cava status) can be done in instant. Together with above mentioned evaluation of thorax, ultrasound can in only 2-3 minutes give the physician a reliable diagnosis of acute dyspnea or shock. Add to this testing for free abdominal fluid, evaluating aorta and DVT diagnosis of lower extremities and then we have a full RUSH protocol (also known as FATE): RUSH: Rapid ultrasound for Shock and Hypotension
Yes folks, the ultrasound is certainly here to stay!
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