Complications of awake fibreoptic intubation without sedation in 200 healthy anaesthetists attending a training course.

BACKGROUND: Two hundred anaesthetists underwent airway endoscopy and attempted awake fibreoptic intubation (FOI) on a training course. Complications were recorded and each subject's response to the procedure was assessed. METHODS: Topical airway local anaesthesia was produced with up to 9 mg kg(-1) of lidocaine, sedation was not used. Complications during and after the procedure were noted. Later, the subjects completed an anonymous questionnaire about anxiety, pain, coughing, and side-effects of lidocaine. RESULTS: More than 1300 endoscopies were performed, 180 delegates were intubated, 175 by the nasal route and five orally. Intubation was abandoned in 20 (10%) subjects. Nasal bleeding occurred in 20 (10%) subjects. Symptoms that could be attributed to lidocaine were reported by 71 (36%) subjects. Afterwards, two (1%) subjects experienced rigors and one developed a lower respiratory tract infection. CONCLUSIONS: Nasendoscopy and FOI under local anaesthesia are associated with complications, notably those of infection and airway trauma. Side-effects potentially attributable to lidocaine administration were commonly reported.

Combined nebulization and spray-as-you-go topical local anaesthesia of the airway.

BACKGROUND: Twenty-five anaesthetists underwent awake fibreoptic intubation using a combination of nebulization and topical local anaesthesia. Plasma lidocaine concentrations were measured and the quality of the local anaesthesia was assessed. METHODS: After i.v. glycopyrrolate 3 microg kg(-1) and intranasal xylometolazone 0.1%, lidocaine 4% 200 mg was administered by nebulizer. Supplementary lidocaine to a maximum total of 9 mg kg(-1) was applied directly and via a fibreoptic endoscope. Nasotracheal intubation was performed once the vocal cords became unreactive. Heart rate, non-invasive blood pressure and oxygen saturation were recorded at 5-min intervals. Blood sampling commenced with a baseline sample and continued at 10 min intervals until 60 min after final administration of local anaesthetic. Subjects graded levels of anxiety, pain and coughing using written and visual analogue scales. RESULTS: Conditions for fibreoptic endoscopy and intubation were good. Seventeen received the maximum lidocaine dose of 9 mg kg(-1). The average dose used was 8.8 mg kg(-1). All plasma lidocaine concentrations assayed were below 5 mg litre(-1). Four volunteers reported feeling lightheaded after the procedure, despite normal blood pressure. Of these, two had the highest plasma lidocaine concentrations recorded: 3.5 and 4.5 mg litre(-1). Twenty-two of the 25 subjects found endoscopy and intubation acceptable, three found it enjoyable and no subject rated it as distressing. CONCLUSIONS: This method of airway anaesthesia was acceptable to this small group of unsedated subjects. It produced good conditions for fibreoptic intubation. A maximum calculated lidocaine dose of 9 mg kg(-1) did not produce toxic plasma concentrations of lidocaine.

Genetic diversity within populations of cyanobacteria assessed by analysis of single filaments.

We have developed a technique for determining the genetic structure of populations of filamentous cyanobacteria. The sequence diversity at specific gene loci is first characterised in a range of clonal cultures; subsequent analysis involves individual trichomes collected directly from natural populations. This technique has been used to examine the population genetic structure of Nodularia in the Baltic Sea and Planktothrix in Lake Zürich. For Nodularia, studies utilising four polymorphic loci reveal that even though there is a degree of linkage disequilibrium, horizontal transfer of genetic information has been sufficient to generate many of the possible allelic combinations. Analyses reveal both spatial and temporal variation in population genetic structure. Other studies of both Nodularia and Planktothrir have shown a correlation between particular alleles at the gvpC locus and the critical pressure of the gas vesicles that accumulate within the cell. We are now investigating how the natural selection of different gas vesicle phenotypes, imposed by changes in the depth of the upper mixed layer of the water column, affects the relative success of individual cyanobacteria possessing different gvpC alleles.

Training course in local anaesthesia of the airway and fibreoptic intubation using course delegates as subjects.

BACKGROUND: We describe a practical method of training anaesthetists in the technique of awake fibreoptic intubation. This is performed on a training course using the delegates as subjects. METHODS: The first 15 subjects underwent cardiovascular monitoring during airway fibreoptic endoscopy performed by other course members. They were subsequently interrogated by use of a questionnaire. RESULTS: Evidence from questionnaires suggests this method of instruction is acceptable in this self-selected group of individuals. Gagging was the commonest unpleasant side-effect of airway endoscopy, although only one delegate rated this as uncomfortable. Fifty-four per cent of subjects found the procedure slightly painful; 46% reported no pain at all. Overall, the procedure was rated as acceptable by 85% of subjects and enjoyable by 15% of subjects. No delegate found endoscopy or intubation distressing. Cardiovascular monitoring revealed pulse rate and arterial pressure changes of less than 25% of baseline values. Paraesthesia developed in one individual and nasal bleeding in two cases, neither of which was clinically significant and did not interfere with endoscopy. CONCLUSIONS: The use of course delegates as subjects for training was acceptable to anaesthetists and is associated with a low level of discomfort and morbidity.

The Pathfinder High-Speed E.C.G. Analyser. Use in detection of arrhythmias during oral surgery.

Automatic analysis of arrhythmias from a tape recorded electrocardiogram (e.c.g.) is described, and its application to the detection and comparison of these during halothane and enflurane anesthesia is discussed. The results confirm that the use of enflurane during oral surgery produces much greater cardiac stability than the use of halothane.