“A Multicenter, Randomized Trial of Ramped Position versus Sniffing Position during Endotracheal Intubation of Critically Ill Adults.” Semler et al. Chest 2017.
Is there enough data to change the ramped trend?
Objective: The ramped position has been gaining popularity over the last decade for improvement in functional residual capacity and ease of intubation. However, studies on this method have been in controlled settings such as the OR. This study aimed to compare the ramped versus the traditional sniffing position in critical care units with intubations by critical care fellows. The primary outcome was lowest desaturation with secondary outcomes such as grade of view and subjective difficulty.
Methods: This study enrolled 260 adults intubated in the ICU setting by fellows at four academic institutions. For patients randomized to the ramped position, the bed was placed in a 25 degree angle with the patient’s face parallel to the ceiling. For the sniffing position, towels were used under the patient’s head to flex the neck and extend the head. A pictorial demonstration of each was present at the time of intubation. Lowest O2 sat was recorded up to 2 minutes after intubation.
|Ramped Position||Sniffing Position||Sig-nificance|
|Lowest SpO2||93%||92%||p 0.27|
|First pass success||76.2%||85.4%||p 0.02|
|Time to secured airway||119s||110s||p 0.09|
|Grade 3 or 4 view||n = 33||n =15||p 0.01|
|Moderate or difficult intubation||n = 42||n =24||p 0.04|
|Switch from direct to video||n = 17||n = 8||p 0.01|
|More than one attempt||n = 31||n = 19||p 0.02|
A post-hoc analysis of all characteristics per BMI – as in, do obese patients favor ramped versus sniffing- showed no difference in probability of grade I or II view, number of attempts, subject’s difficulty or time to intubation.
The data from this study supports the traditional sniffed position for all secondary outcomes without demonstrable difference in lowest oxygen saturation. A big strength of this study is that it was performed outside of the OR and in critical care units, making it one of the most relevant studies to date. The discussion in the article mentions that of the studies randomizing these positions, most were in the OR and not all had clinical outcomes relative to EM or CC medicine. This study is a rebuttal to 10 years of data recommending the ramped position and even more so in obese populations. The ramped positioning is known to increase safe apneic periods and lead to improved pre-oxygenation. One of the defining studies from 2004 was a randomization of 60 obese patients undergoing bariatric surgery which demonstrated greater laryngeal view with the ramped positioning. However this did not measure clinically significant outcomes such as desaturation or first pass success. This is directly contended in the post-hoc analysis showing no difference in laryngeal views in obese patients. The other more recent study from 2015 was a randomization of 204 OR patients to ramped positioning or sniffing and documented higher first pass success and laryngeal view with ramped positioning. This is as similar as we can find in the current literature except in the OR arena.
At this point we have to ask, what are the clinically important outcomes? In this study, there was no significant difference in desaturation, begging the question, do the secondary outcomes make a difference in patient care? First pass success is frequently an airway measure, but what does a lower first pass success mean without other meaningful measures such as mortality, hypoxemia, hypotension etc.? The other major question to ask is how much can we extrapolate data from ORs and ideal intubating circumstances and apply those results to the uncontrolled and often difficult setting of the ED? The majority of data supporting ramped positioning comes from OR studies yet whereas this is the first study to compare positioning in the ICU, the closest we have to the emergency department. Overall, I have to applaud the authors: this was a well-designed, prospective trial involving four sites and likely will be the only article of this caliber for some time.
Comparison of the rate of successful endotracheal intubation between the “sniffing” and “ramped” positions in patients with an expected difficult intubation: a prospective randomized study. Ju-Hwan Lee, Hoe-Chang Jung, Ji-Hoon Shim, Cheol Lee. Korean Journal of Anesthesiology 2015, 68 (2): 116-21
Laryngoscopy and morbid obesity: a comparison of the “sniff” and “ramped” positions. Jeremy S Collins, Harry J M Lemmens, Jay B Brodsky, John G Brock-Utne, Richard M Levitan. Obesity Surgery 2004, 14 (9): 1171-5
Article Review by Terren Trott @tsquaredmd