Tracheal Intubation In Adults Research Articles

A documented previous difficult tracheal intubation as a prognostic test for a subsequent difficult tracheal intubation in adults

We investigated the diagnostic accuracy of a documented previous difficult tracheal intubation as a stand-alone test for predicting a subsequent difficult intubation. Our assessment included patients from the Danish Anaesthesia Database who were scheduled for tracheal intubation by direct laryngoscopy. We used a four-point scale to grade the tracheal intubation. A previous difficult intubation was defined according to the presence of a record documenting a difficult penultimate tracheal intubation-score for the 15 499 patients anaesthetised more than once. Our assessment demonstrates that a documented history of previous difficult or failed intubation using direct laryngoscopy are strong predictors of a subsequent difficult or failed intubation and may identify 30% of these patients. Although previous investigators have reported predictive values that exceed our findings markedly, a documented previous difficult or failed tracheal intubation appears in everyday anaesthetic practice to be a strong predictor of a subsequent difficult tracheal intubation.

Use of the intubating laryngeal mask in children: an evaluation using video-endoscopic monitoring

Background and objective The intubating laryngeal mask is designed to act as a ventilatory device and as an aid to blind tracheal intubation in adults. The aim of this study was to evaluate the efficacy of the intubating laryngeal mask for ventilation of the lungs and tracheal intubation in children using video-endoscopic control. Methods The handling and efficacy of the size 3 intubating laryngeal mask for tracheal intubation in 80 children weighing ≥ 25 kg were assessed under video-endoscopic control. Ease of intubating laryngeal mask insertion, adequacy of lung ventilation through the intubating laryngeal mask and airway sealing pressures were recorded. Tracheal intubation was performed blindly by the intubator, while the supervisor observed the procedure on the video display. If blind intubation failed at the first attempt, the monitor view was used to guide the tracheal tube into the trachea. The success rate and time required for successfully placing the tracheal tube were recorded. Results Insertion of the intubating laryngeal mask was easy in all children. Lung ventilation through the intubating laryngeal mask was uniformly excellent. Blind tracheal intubation at the first attempt was successful in 53 children (66%) within 18.8 ± 4.1 s. Twenty-four of the 27 failed blind intubation attempts were successfully intubated with video-endoscopic guidance within 28.6 ± 9.4 s. Two children required replacing the intubating laryngeal mask, one child had to be intubated conventionally. Conclusions The size 3 intubating laryngeal mask provides an airway that is easy to establish in children ≥ 25 kg with excellent ventilation conditions and allows blind tracheal intubation at the first attempt with a high success rate. Endoscopic monitoring improves its safety and intubation success rate.

PRIMING WITH CISATRACURIUM A DOSE RANGING STUDY

S322 INTRODUCTION: Cisatracurium besylate (CAB) is a potent non-depolarizing muscle relaxant with an ED95 of 0.05 mg/kg in adults. Compared with its stereoisomer atracurium besylate (AB), CAB lacks histamine release and consequently offers a more stable hemodynamic profile. However, the time to maximal block for equipotent doses with CAB is up to 2 min longer than with AB [1]; therefore in order to shorten CAB onset time, 4XED95 dose has been recommended for tracheal intubation in adults. This study assesses the pharmacodynamic effects of the priming technique on different intubating doses of CAB. MATERIALS AND METHODS: This is an open label randomized study. After obtaining IRB approval and written informed consent, 40 adult female patients, ASA I-III, undergoing elective surgery under general anesthesia, were enrolled into one of 4 groups (Table 1). All patients were premedicated with midazolam 2-4 mg iv and induced with thiopental 3-5 mg/kg and sufentanil up to 0.5 mcg/kg. An inhalational mixture of N2 O/O2 (60/40%) was delivered after 3 min of pre-oxygenation. Mechanomyography assessed the neuromuscular function of the adductor pollicis by stimulating the ulnar nerve with TOF every 12 sec. After obtaining a stable baseline, a priming dose (CAB or placebo) was administered, followed 4 min later by the intubating dose. All patients were intubated at T1 <or=to20% and the degree of vocal cords relaxation was evaluated according to the criteria of Lund and Stovner [2]. Anesthesia was maintained with isoflurane up to 0.7% ET in a mixture of N2 O/O2 (60/40%) and sufentanil used as clinically indicated. Ventilation was adapted to produce 30-37 mmHg ETCO2 and local temperature was maintained >33.5[degree sign]C. If deemed necessary, reversal with neostigmine or edrophonium was allowed only after T1 spontaneous recovery >25%.Table 1: Priming and intubating doses of CAB in each group. Number of patients in parenthesis.RESULTS: Table 2 and Table 3 show the intubating conditions and the pharmacodynamic data in all groups. As this is an interim report, statistical analysis has been withheld until an additional 20 patients are enrolled.Table 2: Intubating conditions in different groups.Table 3: Pharmacodynamic data represented as mean +/- standard deviation.DISCUSSION: Group 2 seems to benefit the most from the priming technique of CAB when compared to the other groups. In this group, 3XED95 offered an onset time comparable with that of Groups 3 and 4 and allowed an earlier spontaneous recovery. Neither Single Twitch nor TOF ratio have shown any significant depression or fade respectively after the priming dose, which may preclude a possible muscle weakness in an awake patient. Even though the priming technique did not accelerate the onset in Group 3 in comparison with Group 4, it is evident that overall intubation conditions at T1 <or=to20% were better in Group 3. ACKNOWLEDGMENT: This project is supported by GlaxoWellcome.

Assessment of an angulated laryngoscope for difficult paediatric intubation

SummaryAngulated laryngoscopes with mirrors and prisms have been previously described for difficult tracheal intubation in adults, but not in children. We assessed the use of a recently described adult angulated laryngoscope (BelscopeTM) with or without prism, for difficult tracheal intubation in children. We use this laryngoscope as part of our difficult tracheal intubation regime before proceeding to other methods such as fibreoptic tracheal intubation. Children included were anticipated to be a difficult tracheal intubation from physical examination or previously had been difficult to intubate. Laryngoscopy was initially performed with a straight (Miller) or curved (Macintosh) laryngoscope. This was then repeated using the angulated laryngoscope, with prism if necessary. Degree of visualization of the larynx was scored with both methods. There was improvement in visualization in children with micrognathia, prominent maxillae or with an apparent ‘anterior larynx'. In children where there was no improvement, this laryngoscope did not actually cause a deterioration in grade of laryngoscopy.