Effect of 90° Degree Counterclockwise Rotation of the Endotracheal Tube on Its Advancement Through the Larynx During Nasal Fiberoptic Intubation in Children: A Randomized and Blinded Study

A nasal endotracheal tube (ETT) is routinely placed in children and a fiberoptic scope (FOS) is commonly used for this purpose. Resistance to the passage of ETT is frequently encountered as it is advanced over the FOS for placement into the trachea, since it gets hung up on structures of the laryngeal inlet. The aim of the investigators study performed on forty children divided in two groups was to study in the pediatric population, whether a 90° counterclockwise rotation (CCR) of the ETT prior to advancing through the larynx, by nasal approach, prevents it from getting hung up at the laryngeal inlet.Following the approval of Nemours Institutional Review Board, and informed consent, forty healthy children were included in the study.

All children were randomly assigned to one of two groups using a computer generated numbers table. Group-S (Standard technique): It involved placement of ETT over the FOS with bevel of the ETT facing left as is routinely done Group-R (pre-Rotated technique): It involved placement of ETT over the FOS with 90° CCR from the beginning so that the bevel of the ETT faced posteriorly.

All children received midazolam premedication prior to coming to the operating room and were anesthetized by a standard technique using mask induction with oxygen, nitrous oxide and sevoflurane. Intravenous line was placed and rocuronium 0.4 mg/kg body weight was then administered to achieve muscle relaxation. Oxymetazoline hydrochloride lotion (Afrin) was sprayed in both nostrils to achieve nasal mucosal decongestion and the ETT of appropriate size for that age was used for nasotracheal intubation. Small FOS (Olympus LF-P; 2.2 mm diameter) was used for cuffed ETT (MallinckrodtTM; Covidien) sizes 4.5 mm ID and under and larger FOS (Olympus LF-DP; 3.1 mm diameter) was used for cuffed ETT (MallinckrodtTM; Covidien) sizes 5 mm ID and over. ETT was mounted on a FOS and secured near the proximal end close to the eyepiece. With head maintained in neutral position, a lubricated FOS was then advanced through the right or left nostril (the one that looked bigger) into the larynx and once in the trachea, the lubricated ETT was advanced over it.

An unblinded anesthesia attending associated with the study prepared the FOS and ETT according to the randomization, and advanced the FOS into the trachea and the ETT into the posterior pharynx. The anesthesia provider advancing the ETT was always one of the trainees: student nurse anesthetists (SRNA) or resident who was not a part of the study and was blinded to whether or not the ETT has been rotated 90°counterclockwise. The attending member of the research team observed as the ETT was advanced by the trainee and made a note of whether or not the ETT got hung up. If it did, the research team member withdrew the ETT 2 cm, rotated it 90° CCR, and allowed the trainee to advance the ETT one or more times, noting the results.

Following parameters would be measured: