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: Can We Use LR for Hyperkalemia?

Spoon Feed
Use of balanced fluid, such as LR, did not increase the risk of severe hyperkalemia, even when given to patients with a K of 6.5 mmol/L.

Why does this matter?
We covered SMART a while back. And we covered when NOT to use LR. LR has a small amount of potassium but has lower chloride and pH around 6.5. Normal saline (NS) has a lower pH, higher chloride, and potential for hyperchloremic metabolic acidosis, which favors a shift of potassium out of cells. Should we used balanced fluids like LR for hyperkalemic patients, or is NS better?

Restoring potassium balance
This was a secondary analysis of the SMART trial including 187 patients with hyperkalemia (>6.5mmol/L) and 1,324 with acute kidney injury on ICU admission, that were evenly split between the balanced fluid and NS cohorts. There was no statistical difference in severe hyperkalemia (>7.5) among patients with initial hyperkalemia: 8 patients (8.5%), balanced fluid; 13 patients (14.0%), NS (aOR 0.57, 95%CI 0.22-1.46; P=0.24). As in SMART, fewer of these patients needed renal replacement therapy (RRT) or developed new or worsening AKI. Patients with AKI on ICU admission also had no statistical difference in progression to severe hyperkalemia: 3 (0.4%), balanced fluid; 9 (1.4%), NS (aOR 0.33, 95%CI 0.09-1.25; P=0.10). Statistically fewer balanced fluid patients needed RRT. Potassium lowering therapies were no different between groups. This is a dogma-buster. It’s reasonable to choose LR to treat hyperkalemia over NS.

Balanced Crystalloids versus Saline in Critically Ill Adults with Hyperkalemia or Acute Kidney Injury: Secondary Analysis of a Clinical Trial. Am J Respir Crit Care Med. 2021 Jan 27. doi: 10.1164/rccm.202011-4122LE. Online ahead of print.

#2: Topical Pain Relief for Corneal Abrasion – A Systematic Review

Spoon Feed
Topical NSAIDs improved pain from corneal abrasion. The jury is out on other options per this review.

Why does this matter?
We have covered both a large retrospective study and a RCT looking at topical tetracaine for corneal abrasion. It works. That doesn’t seem to be in question (except in this systematic review). Is it safe? That is the key question this review can’t answer.

Would you like some drops so it no longer feels like there’s a red hot poker in your eye?
This was a systematic review and meta-analysis of 31 RCTs and 2 observational studies, 4,167 total patients, using various topical agents or patching for corneal abrasions. There was only enough combined data to draw firm conclusions on topical NSAIDs, which reduced pain at 24 and 48 hours. These patients also used less oral pain medication. The authors stated there was not enough evidence to show reduction in pain from topical anesthetics, cycloplegics, pressure patching, or a bandage contact lens. None of the treatments impaired healing, except perhaps pressure patching. I don’t recommend patching. They concluded there was insufficient evidence to determine if topical anesthetics reduced pain. Several individual studies have shown pain reduction, but apparently they could not be meta-analyzed. Call me anecdotal, but I’m a believer, having repeatedly seen these agents drastically reduce pain within seconds when I administer them in the ED. I was hoping to get clarity on the key question: are topical anesthetics safe? Instead, we still don’t know with certainty. The largest studies have shown no difference in healing or complications with topical anestetics, but none were powered to detect rare complications. Here is my bottom line. Topical NSAIDs work and appear safe. But even they can melt your patient’s eyeball, especially if given with topical steroids. I think this is a place for shared decision making when considering topical anesthetics. We know the risk is low. We are pretty sure pain control is significant. We want to avoid opioids. I would want to take the risk for myself or my family in the case of a simple, uncomplicated corneal abrasion and would use dilute proparacaine. Get the recipe on REBEL EM!

Another Spoonful
Salim Rezaie, REBEL EM, gives a tour de force on topical anesthetics for corneal abrasions you don’t want to miss, including how to mix up dilute proparacaine.

Topical Pain Control for Corneal Abrasions: A Systematic Review and Meta-Analysis. Acad Emerg Med. 2021 Jan 28. doi: 10.1111/acem.14222. Online ahead of print.

Spoon Feed
Prevalence of pulmonary embolism (PE) was about 6% in this prospective trial looking at patients admitted to the hospital with worsening respiratory symptoms in the setting of known COPD.

Why does this matter?
In a patient with a history of COPD who presents with acute shortness of breath, there is often the lingering question in the back of our minds: what about PE? Prior studies have reported a high prevenance of PE in patients with COPD ranging anywhere from 19 to 29% (1-3). A recent systematic review and meta-analysis in Chest and summarized by JF (880 patients) found a pooled prevalence of PE in unexplained COPD exacerbations to be 16% – albeit with wide 95% confidence intervals (8.3%-25.8%). Further, this prevalence matters given mortality and length of hospital admission seem to be increased in patients with acute COPD exacerbations and PE (4).

“Sure. It could all be the COPD, but what about PE?” – the voice in the back of your head (or maybe just my head. Is someone burning toast?)
This was a multicenter cross-sectional study of 740 patients with prospective follow-up at 3 months. Patients had confirmed COPD and were admitted to the hospital with worsening respiratory symptoms.

Overall, 5.9% of patients had confirmed pulmonary embolism at 48 hours of admission. Among those patients who did not have PE diagnosed at admission and who did not receive anticoagulation, 5 patients (0.7%) developed PE at 3-month follow-up. 3-month mortality was 6.8%, with patients diagnosed with PE within 48 hours of admission having higher mortality than those without PE on admission.

This study provides high quality, prospective evidence that the prevalence of PE in patients with COPD admitted for respiratory symptoms is lower than that reported in prior reviews but still an important consideration in this population. Authors note that further research is needed to risk-stratify and screen this specific population. In the interim, let’s continue to risk-stratify these patients with the tools available to us, and use our D-dimer when needed!

Prevalence of Pulmonary Embolism Among Patients With COPD Hospitalized With Acutely Worsening Respiratory Symptoms. JAMA. 2021 Jan 5;325(1):59-68. doi: 10.1001/jama.2020.23567.

Bonus reading on clinician gestalt and risk stratification used in this study
Initially, clinician judgment was used to classify patients as clinically suspected or not suspected of having a pulmonary embolism AND as having a diagnosis other than pulmonary embolism more or less likely. Clinical probability of PE was subsequently assessed in all patients using the Revised Geneva Score. Patients with high pre-test probability (n=17) were imaged. Patients with Low to intermediate pre-test probability had D-dimers ordered (n=723). Of those patients with +D-dimers (n=500), 95% underwent CTPA. The prevalence of PE reached 10% when suspected using clinician gestalt, but remained just above 3% in patients without clinical suspicion. Check out Table 3.

From cited article

From cited article

Reviewed by Clay Smith

Works Cited

  1. Akpinar EE, Hoşgün D, Akpinar S, Ataç GK, Doğanay B, Gülhan M. Incidence of pulmonary embolism during COPD exacerbation. J Bras Pneumol 2014;40:38-45.

  2. Tillie-Leblond I, Marquette CH, Perez T, et al. Pulmonary embolism in patients with unexplained exacerbation of chronic obstructive pulmonary disease: prevalence and risk factors. Ann Intern Med 2006;144:390-6.

  3. Rizkallah J, Man SFP, Sin DD. Prevalence of pulmonary embolism in acute exacerbations of COPD: a systematic review and metaanalysis. Chest 2009;135:786-93.

  4. Aleva FE, Voets L, Simons SO, de Mast Q, van der Ven A, Heijdra YF. Prevalence and Localization of Pulmonary Embolism in Unexplained Acute Exacerbations of COPD: A Systematic Review and Meta-analysis. Chest 2017;151:544-54.

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