Assisted head extension minimizes the frequency of dental contact with laryngoscopic blade during tracheal intubation.

OBJECTIVES: We hypothesized that the assisted maintenance of head extension would reduce the frequency of direct contact between the laryngoscope blade and the maxillary incisors during tracheal intubation. METHODS: Sixty-eight patients undergoing elective surgical procedures under general anesthesia were enrolled in this prospective, randomized, controlled crossover study. A single experienced anesthesiologist performed the simulated tracheal intubations with a classic Macintosh laryngoscope. After reaching the sniffing position during direct laryngoscopy, tracheal intubations with and without maintaining the head extension (by an assistant) were simulated twice in each patient in random order. The occurrence of dental contact with the laryngoscope blade was recorded during the simulated tracheal intubation. The distance between the laryngoscopic blade and maxillary central incisors was assessed using a digital caliper. The angle of head extension and the glottic view were also evaluated. RESULTS: The frequency of dental contact was lower with the assisted head extension than without it (25/68 [37%] vs 67/68 [99%], P < .001). The blade-to-tooth distance was longer with assistance than without it (1.8 ± 1.9 [0-8] mm vs 0.0 ± 0.1 [0-1] mm, P < .001). The angle of head extension was greater with assistance than without it (26.6° ± 5.8° [6.0°-37.4°] vs 19.9° ± 5.4° [3.4°-31.8°], P < .001). No significant difference was observed between 2 simulated tracheal intubations with regard to the glottic views. CONCLUSION: The assisted maintenance of head extension during the simulation of tracheal intubation reduced the frequency of dental contact with the laryngoscopic blade without compromising the laryngoscopic views. The results of this study suggest that assisted head extension during tracheal intubation may reduce the possibility of unexpected dental injury.

A new technique to reduce epistaxis and enhance navigability during nasotracheal intubation.

BACKGROUND: Epistaxis is the most common complication of nasotracheal intubation. We compared endotracheal tubes (ETT) obturated with an inflated esophageal stethoscope with normal ETTs with regard to the prevention of epistaxis and navigability, both with and without thermosoftening. METHODS: Dental surgical patients requiring nasotracheal intubation were randomly allocated into 1 of 4 groups (n = 50 each): Group 1, nonthermosoftened ETTs; Group 2, nonthermosoftened ETTs obturated with an inflated esophageal stethoscope; Group 3, thermosoftened ETTs; and Group 4, thermosoftened ETTs obturated with an inflated esophageal stethoscope. Navigability of ETTs through the nasal cavity and postintubation epistaxis were evaluated. RESULTS: Navigability of ETTs through the nasal cavity was the worst in Group 1 (P = 0.001). Epistaxis was the most severe in Group 1, similar between Groups 2 and 3, and the least severe in Group 4 (P < 0.001). CONCLUSION: The use of esophageal stethoscope-obturated ETTs was effective, and comparable to thermosoftening, in preventing epistaxis associated with nasotracheal intubation. Thermosoftened, obturated ETTs were more effective than simple thermosoftened ETTs in reducing epistaxis.

Effects of airway evaluation parameters on the laryngeal view grade in mandibular prognathism and retrognathism patients.

BACKGROUND: Failure to maintain a patent airway can result in brain damage or death. In patients with mandibular prognathism or retrognathism, intubation is generally thought to be difficult. We determined the degree of difficulty of airway management in patients with mandibular deformity using anatomic criteria to define and grade difficulty of endotracheal intubation with direct laryngoscopy. METHODS: Measurements were performed on 133 patients with prognathism and 33 with retrognathism scheduled for corrective esthetic surgery. A case study was performed on 89 patients with a normal mandible as the control group. In all patients, mouth opening distance (MOD), mandibular depth (MD), mandibular length (ML), mouth opening angle (MOA), neck extension angle (EXT), neck flexion angle (FLX), thyromental distance (TMD), inter-notch distance (IND), thyromental area (TMA), Mallampati grade, and Cormack and Lehane grade were measured. RESULTS: Cormack and Lehane grade I was observed in 84.2%, grade II in 15.0%, and grade III in 0.8% of mandibular prognathism cases; among retrognathism cases, 45.4% were grade I, 27.3% grade II, and 27.3% grade III; among controls, 65.2% were grade I, 26.9% were grade II, and 7.9% were grade III. MOD, MOA, ML, TMD, and TMA were greater in the prognathism group than in the control and retrognathism groups (P < 0.05). The measurements of ML were shorter in retrognathism than in the control and prognathism groups (P < 0.05). CONCLUSIONS: Laryngoscopic intubation was easier in patients with prognathism than in those with normal mandibles. However, in retrognathism, the laryngeal view grade was poor and the ML was an important factor.

A comparison of ketamine and lidocaine spray with propofol for the insertion of laryngeal mask airway in children: a double-blinded randomized trial.

UNLABELLED: The laryngeal mask airway (LMA) has been used successfully as both a ventilatory device and a conduit for tracheal intubation. In this double-blinded, randomized study, we examined whether pretreatment with lidocaine spray, ketamine anesthesia, and LMA insertion could be used as airway management that could maintain spontaneous breathing in children. After IV premedication with midazolam 0.05 mg/kg and glycopyrrolate 0.005 mg/kg, 90 patients were randomly allocated to 1 of 2 main groups for the administration of either propofol or ketamine: 40 patients received 2.5, 3.0, 3.5, or 4.0 mg/kg of propofol IV (n = 10 each), whereas 50 patients received 2.0, 2.5, 3.0, 3.5, or 4.0 mg/kg of ketamine IV (n = 10 each). Only in the ketamine group was lidocaine spray applied to the oropharynx 1 min before anesthesia induction. After injection of the designated drug, self-respiration, airway obstruction, and jaw relaxation were checked. Self-respiration, laryngospasm coughing, gagging, swallowing, biting or tongue movements, secretions, and head or limb movements after LMA insertion were graded. All variables were graded as satisfactory, acceptable, or unsatisfactory. The overall result was considered satisfactory if all criteria were satisfactory; acceptable if all were better than acceptable, but at least one acceptable criterion was included; and unsatisfactory if at least one criterion was unsatisfactory. Overall satisfactory or acceptable results in every patient were achieved only in the ketamine 3.0 or 3.5 mg/kg subgroups. No propofol dose was completely satisfactory; most cases involved apnea or airway obstruction. Ketamine and lidocaine spray were appropriate for LMA insertion, which may be a safe method for management of difficult airway in children. IMPLICATIONS: Ketamine and lidocaine spray appear to be appropriate for laryngeal mask airway (LMA) insertion in children. Thus, apnea and airway obstruction, the two most serious and frequent complications of propofol, can be avoided during LMA insertion.