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: How to Prevent Post-LP Headaches

Spoon Feed
Risk for post-LP headache can be lessened by using atraumatic non-cutting needles, which, contrary to popular belief, are not more difficult to use than traditional cutting needles. Utilizing the lateral decubitus position, a higher intervertebral space, and orienting the needle bevel parallel to the spinal axis may also decrease risk. Other common recommendations, including IV fluids, caffeine, and bed rest are unlikely to help.

Why does this matter?
Lumbar puncture (LP) is a common ED procedure, and the risk for post-LP headache is reported anywhere from 3-33%. We can’t change some factors that are associated with this complication, such as female sex, lower BMI, younger age, and history of headaches. But, there are many other factors that are under our control such as needle choice, procedure technique, and post-procedural recommendations.

Less pain from the puncture
This article reviewed literature from 2000-2020 to evaluate headache in patients after diagnostic lumbar puncture. Nineteen FAQs in four major categories regarding post-LP headache were identified, and the answers were determined along with a rating of the available evidence for each question. The table in this article gives a great summary; here’s an even shorter one below:

  • Who is at increased risk?  Female sex, lower BMI, younger age, and history of headaches may lead to increased risk.

  • Which needle should I use? Atraumatic needles are definitely effective to reduce this complication and are not more difficult to use.

  • What specific technique should I use? Lateral decubitus position, a higher intervertebral space, and orientation of the bevel parallel to the spinal axis are all possibly associated with lower risk. Difficult taps, higher volume taps, and aspirating CSF do not increase risk.  The jury is still out on needle diameter and stylet reinsertion.

  • What can I do after the LP to reduce this risk? IV fluids and caffeine do not reduce risk. Bed risk doesn’t reduce risk and may actually increase it; evidence favors immediate mobilization. More research is needed to determine if pharmacologic agents such as  frovatriptan, morphine, cosyntropin, or aminophylline might be helpful.

Preventing Post-Lumbar Puncture Headache. Ann Emerg Med. 2021 May 6;S0196-0644(21)00151-7. doi: 10.1016/j.annemergmed.2021.02.019. Online ahead of print.

#2: Managing the Difficult Airway

Spoon Feed
The difficult airway is rare, and adverse events from difficult airways are higher in the ED than other settings.  With the cornerstone of expert clinical technique and skills, the main areas of focus in the difficult airway are airway assessment, planning, and appropriate response to difficulty, in combination with human factors.

Why does this matter?
Management of the airway is a requisite skill for emergency providers – but what separates the wheat from the chaff is the ability to manage the difficult airway. There are over 15 million intubations per year in the United States, with ~350,000 of them occurring in the emergency department. While the incidence of a difficult airway is low, given the sheer volume of ETTs being put into tracheas each year, any small change in performance will carry great weight. We need to be able to handle difficult intubations and handle them well.

Knees weak, arms heavy, the patient’s airway is filled with mom’s spaghetti
The incidence of difficult tracheal ventilation ranges from 5-8%, with failed intubation representing 0.05-0.35% of all attempts. When performing any airway, you should be predicting the difficult airway and reacting quickly and effectively to the problem.

Remember there are both anatomically and physiologically difficult airways.

  • The best predictor of a difficult airway is a known difficult airway – but this is not always feasible information to obtain.

  • The best anatomic predictor we have to date is the upper lip bite test – which is difficult to ask critically ill patients to perform and still only gets us to 60% sensitivity.

  • Most of the other tests are abysmal predictors – I’m looking at you, Mallampati.

In short, predicting a difficult airway, especially in the ED, is not always feasible. We must be mentally and structurally prepared for any intubation to be difficult. There is no harm in predicting a difficult airway and having it end up being an easy one. It’s better to overestimate and over-prepare.

There are both anticipated and unanticipated difficult airways.

  • Difficultly with bag-valve-masking – performing an airway isn’t just passing the tube, it starts the moment you decide to intubate. BVM can save you from difficulty with laryngoscopy or intubation. If you are running into trouble, have ready and reach early for airway adjuncts (NP and oral airways).

  • Difficulty with supraglottic placement – the role of supraglottic airways as a primary means of ventilation and a rescue device are critical. Everyone says an LMA is easy, but it’s a bit harder than it looks, especially in a mangled face. Know your equipment and don’t be afraid to buy time by placing one.

  • Difficult laryngoscopy or tracheal intubation – there’s no point in having fancy tools if you aren’t going to use them. When faced with a difficult airway, reach for the video laryngoscope and bougie, and don’t be afraid to fall back on your supraglottic or BVM.

  • Can’t intubate, can’t ventilate – cut the neck. It’s not a failed airway if the patient is oxygenated and ventilated; don’t delay if the situation is getting worse.

The big takeaway here is to take every airway seriously. Hone your skills so you can rise to the occasion when you are faced with your next difficult intubation. It’s coming, even if you don’t know it.

Another Spoonful
This article also discussed awake intubation and extubation of the patient with known or predicted difficult airway. Our audience is doing primarily RSI, so I chose to focus on that. If you want to read more, check out the whole article below – it’s excellent.

Management of the Difficult Airway. N Engl J Med. 2021 May 13;384(19):1836-1847. doi: 10.1056/NEJMra1916801.

Spoon Feed
CTA alone was not sufficient to rule out esophageal injury in patients with penetrating neck trauma.

Why does this matter?
Morbidity from missed esophageal injury occurs in up to half of patients, and mortality is also high, in up to one-third. The quality and resolution of CTA continues to improve and is the gold standard for evaluating vascular neck injuries. Is CTA alone enough to rule out aero-digestive injuries (ADI)?

Don’t forget the food tube
This was a systematic review and meta-analysis of 7 diagnostic studies, with a total of 877 patients with penetrating neck trauma and CTA. The authors were interested whether ADI lacking “hard signs” could be detected with CTA alone. Prevalence of ADI was 13.4%. CTA was 92% sensitive, 88% specific; positive LR 12.2, negative LR 0.14. This seemed pretty good. However, when considering the 26 esophageal injuries detected at surgery or with a swallow study, 5 were initially missed on CTA. The authors concluded that CTA was not sufficient to rule out esophageal injury in patients with penetrating neck trauma.  The studies included were at risk for incorporation bias and ascertainment bias. These biases may falsely impact diagnostic accuracy.

Computed Tomography Angiography for Aero-digestive Injuries in Penetrating Neck Trauma; A Systematic Review. Acad Emerg Med. 2021 May 21. doi: 10.1111/acem.14298. Online ahead of print.


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