Nasotracheal intubation over a bougie (NIB) may result in less nasal trauma than conventional nasotracheal intubation (CVT), a recent study suggests.
CVT, with blind advancement of the tube through the nares, takes less time but is associated with a higher incidence of nasal bleeding and Magill forceps use, according to researchers.
“Conventionally, nasotracheal intubation is associated with significant trauma, upwards of 50%,” said study author Ron Abrons, MD, assistant professor of anesthesiology and director of airway management training and research at the University of Iowa Carver College of Medicine, in Iowa City. “We’ve worked out a technique that significantly decreases both the incidence and degree of that trauma.”
The technique builds on the red rubber catheter technique studied by Elwood et al (Anesthesiology 2002;96:51-53), which uses a red rubber catheter to guide the endotracheal tube from the nares into the pharynx. The red rubber catheter technique decreases the severity, but not the incidence, of nasopharyngeal trauma and requires Magill forceps for oropharyngeal catheter retrieval, Dr. Abrons noted.
“We’ve been working on this novel technique for 10 years. We have taken the red rubber technique one step further, and instead of using the red rubber catheter to guide the tube into the pharynx, we use a pediatric bougie to guide the tube all the way into the trachea.
“We’ve recently published a case series of the technique, including one patient who may have proved impossible to intubate utilizing a conventional technique, as there was no room for both a laryngoscope and manipulation of Magill forceps in the mouth [J Clin Anesth 2016;34:609-611],” said Dr. Abrons, who spoke at the annual meeting of the Society for Airway Management.
Less Bleeding With NIB technique
The researchers conducted a prospective, randomized controlled study to test the efficacy of NIB. The study included 257 non-anticoagulated patients needing elective nasal intubation. Patients were randomly assigned to receive CVT or NIB. Both groups received nasal oxymetazoline, warmed nasal RAE [Ring, Adair and Elwyn] tubes and GlideScope (Verathon) video laryngoscopy.
All airways were placed by a learner (resident or student registered nurse anesthetist), with or without formal training in the assigned technique. A blinded surgical resident evaluated patients for evidence of nasal bleeding at 60 to 90 seconds and five minutes after intubation.
As part of the study, CVT was defined as the blind passage of an endotracheal tube via the nares followed by video laryngoscopy–assisted passage through the glottis. NIB involved video laryngoscopy–assisted glottic passage of a pediatric bougie, placed via a nasal trumpet, for use as a Seldinger guide.
The researchers purposefully analyzed the techniques in learners so the results would be applicable to those without experience with NIB. Dr. Abrons said they wanted to avoid the potential for bias associated with examining the technique in nurse anesthetists already experienced with CVT.
“The benefit of the nasal trumpet is twofold: to protect the nare from the bougie and to guide the bougie toward the glottis,” Dr. Abrons said. “The key is to start with the coudé tip in the anterior-facing direction, to facilitate passage over the arytenoids, then rotate it 180 degrees, to the coudé tip down position, to avoid catching on the anterior commissure or anterior tracheal rings. After that, you advance to the carina, remove the nasal trumpet, and it’s the basic Seldinger technique.”
The researchers found that at 60 to 90 seconds, 22% of CVT patients showed active bleeding compared with 13% of patients in the NIB group. Overall, 68% of CVT patients had signs of nasal bleeding at 60 to 90 seconds compared with 55% of NIB patients (P=0.033).
At the five-minute mark, 23% of CVT patients had active bleeding compared with 6% of NIB patients. Overall, nearly 70% of CVT patients reported any signs of nasal bleeding at five minutes compared with 51% of NIB patients (P=0.002).
The researchers used a highly sensitive technique to test for nasopharyngeal trauma. Oral surgeons used surgical retractors to directly visualize the nasopharyngeal opening and perform a circumferential swipe around the tube with sterile gauze.
“This is the largest prospective, randomized controlled nasal intubation study to date. … Previous studies have underestimated nasopharyngeal trauma due to less sensitive, and more subjective, methods of bleeding analysis,” Dr. Abrons said. “That’s why you’ll see higher nasal trauma rates here, in both groups, than in other studies.”
In addition, 9% of NIB intubations required Magill forceps versus 27% of intubations utilizing CVT (P<0.0001). The median time to successful intuba tion on the first attempt was 81 seconds for NIB and 68 seconds for CVT (P=0.004). They also found that NIB had a higher first-pass success rate: 94% compared with 89% for CVT, although the difference was not statistically significant. The study included patients over 8 years of age; researchers found no age-related differences in success rate.