Journal Feed Weekly Wrap-Up

We always work hard, but we may not have time to read through a bunch of journals. It’s time to learn smarter. 
Originally published at JournalFeed, a site that provides daily or weekly literature updates. 
Follow Dr. Clay Smith at @spoonfedEM, and sign up for email updates here.

#1: GCS 8 – Intubate…Right?

Spoon Feed
Patients with isolated head trauma and GCS 7 or 8 had greater odds of mortality when intubated immediately. But this is not the study to override the GCS 8 = intubate dogma.

Why does this matter?
GCS 8 = Intubate! Right? Both ATLS and EAST recommend this. It seems pretty solid for trauma patients, though it shouldn’t be the default trigger to intubate overdose patients. There is nothing magical in the number 8 in guaranteeing loss of airway reflexes nor should we be falsely reassured that patients >8 will reliably retain protective airway reflexes. Since intubation is not without complications, is this a dogma we need to reconsider?

This study isn’t the one that will change practice
This was a retrospective study using the TQIP database that included 2,727 adult patients with isolated head trauma and GCS of 7 or 8. After adjusting for known confounders (i.e. head injury severity score), intubation within 1 hour of arrival (1,866/2,727; 68.4%), was associated with an increased adjusted odds of mortality when compared with delayed or no intubation, aOR 1.79 (95%CI 1.31-2.44), and more complications (i.e. DVT, VAP). Out of the total, 23.4% (638/2,727) were never intubated. Though a small group, patients with delayed intubation (223/2,727; 8.5%) had the worst mortality outcome. Overall mortality rates were 27.4% (delayed > 1h group); 18.7% (immediate <1h group); and 11.4% (never intubated). Delayed intubation was also associated with more ventilator days, more overall complications, and increased length of stay. The authors propose a policy of only immediately intubating isolated head trauma patients ≤45 years, with GCS of 7, and head AIS score 5. They stated this would have reduced 3 unnecessary intubations and led to 7 early rather than delayed intubations. This recommendation would lower the GCS for intubation to 7, which would raise the threshold for intubation. Yet it seems the policy, as proposed, may actually lead to more early intubation (which actually seems to be a good thing). I find the results of the study and the proposed policy to be conflicting. I am also concerned that sicker patients (i.e. sonorous, gurgling) were most likely to receive immediate intubation, confounding the primary outcome. I am trying to envision a situation with a patient with obvious head trauma and GCS ≤8 that I would not intubate prior to going to CT. Also, we usually don’t know head trauma is isolated prior to obtaining more imaging in altered patients. In short, this study is interesting but shouldn’t change practice.

Isolated traumatic brain injury: Routine intubation for GCS 7 or 8 may be harmful! J Trauma Acute Care Surg. 2021 Feb 16. doi: 10.1097/TA.0000000000003123. Online ahead of print.

#2: REALITY RCT – PRBC Transfusion in Acute MI

Spoon Feed
A restrictive vs liberal transfusion strategy in patients with acute MI was non-inferior when considering 30-day MACE (major adverse coronary events).

Why does this matter?
We’ve all heard the analogy that RBCs are like boxcars on a train that carry oxygen to the tissues. Sometimes, you just need more boxcars, right?

REALITY check – boxcars ≠ better outcomes
This was a multicenter RCT with 668 patients with acute MI and hemoglobin 7-10 g/dL. Half had a more liberal hemoglobin transfusion trigger of <10; the other half had a more restrictive hemoglobin transfusion trigger of <7. For the primary outcome of 30-day MACE, there was no statistical difference: 11% restrictive vs 14% liberal; difference -3.0%, 95%CI -8.4% to 2.4%. The relative risk of MACE was 0.79; the 1-sided 97.5%CI was 0.00-1.19, which was below the pre-specified non-inferiority threshold of 1.25 (but still could indicate the potential for harm). All cause mortality was also lower in the restrictive group: 5.6% vs 7.7%. This tells us that the dogma of liberally transfusing patients with acute MI to “add more boxcars” is likely not beneficial and may be harmful. As in critical care patients, a restrictive transfusion strategy appears to be the best option for acute MI.

Effect of a Restrictive vs Liberal Blood Transfusion Strategy on Major Cardiovascular Events Among Patients With Acute Myocardial Infarction and Anemia: The REALITY Randomized Clinical Trial. JAMA. 2021 Feb 9;325(6):552-560. doi: 10.1001/jama.2021.0135.

Spoon Feed
There was no difference in 90-day mortality in critically ill patients with significant oxygen requirement between those with a PaO2 target of 60mm Hg vs 90mm Hg.

Why does this matter?
The target PaO2 is elusive in critically ill patients. Not enough oxygen is definitely bad. LOCO2 seemed to worsen outcomes with a low O2 target (PaO2 55-70mm Hg). However, too much oxygen is also bad, i.e. Oxygen-ICU; IOTA; ICU-ROX (null result); huge study in Chest; and yet another study in Am J Respir Crit Care Med. Does a conservative oxygenation target impact meaningful patient outcomes?

HOT-ICU – you ICU hotties!
This was a multicenter RCT with 2,928 patients receiving at least 10L (non-intubated) or 50% (intubated or closed system); half had a 60mm Hg PaO2 target and half had a 90mm Hg PaO2 target. For the primary outcome of 90-day mortality, there was no difference in the groups. There was also no difference in secondary outcomes. What I glean is that we probably can’t put too fine a point on this. Somewhere in the PaO2 60-90mm Hg range (SpO2 ~90-97%) seems to be just fine.

Lower or Higher Oxygenation Targets for Acute Hypoxemic Respiratory Failure. N Engl J Med. 2021 Jan 20. doi: 10.1056/NEJMoa2032510. Online ahead of print.

Leave a Reply

Your email address will not be published. Required fields are marked *