Upper airway tract complications of endotracheal intubation.

The gold standard in airway maintenance is translaryngeal endotracheal intubation, but this is not without its complications. Trauma to the upper airway as a result of the act of endotracheal intubation is a common event in adults undergoing procedures under general anaesthesia. Sites requiring attention during intubation include the laryngeal apparatus, the pharynx and oral cavity as well as the nasal cavity when nasopharyngeal intubation is performed. Patients can present with a range of symptoms which can make assessment and management challenging. Dysphonia, throat pain and dysphagia are the commonest presenting complaints. Patient-related factors, intubation technique and other anaesthetic-related conditions can be a cause of trauma, if not adequately considered before intubation. All patients should be carefully examined preoperatively and their past medical history obtained. Patient demographics, comorbidities, existing airway pathology and presence of reflux should be noted. Trauma prevention strategies should be in place to eliminate avoidable complications. Potential difficult airway cases should be flagged up and adequately prepared for, in anticipation of intubation difficulties that can lead to trauma. The majority of injuries will resolve spontaneously with conservative management. Persistent symptomatology, usually secondary to laryngeal injuries, requires prompt referral to an ear nose and throat specialist with an interest in laryngology for further assessment and treatment.

Thyroglossal surgery in Scotland 1981-2010.

BACKGROUND AND AIMS: Thyroglossal surgery is not common in Scotland with 0.013 procedures performed per 1000 population in 2010. There is a growing practice in surgery to consolidate service providers to ensure a minimum 'case volume', with the belief that this will raise standards and improve co-ordination of services. We investigated thyroglossal surgery to see if this had occurred. METHODS AND RESULTS: Data on thyroglossal surgery performed in Scotland from 1981 to 2010 were obtained from the Information Services Division of NHS Scotland. This was analysed to investigate the number of procedures involving thyroglossal tissue, the surgical speciality of operating surgeon and the health board in which the procedure was performed. Whilst the number of thyroglossal operations has remained essentially static over the study period, there has been a steady trend of consolidation of the surgical speciality performing the procedure. In 1981, 58% of thyroglossal surgery was performed by general surgeons, 18% by paediatric surgeons and 15% by ENT surgeons nationally. In 2010, ENT surgeons are performing 81%. CONCLUSIONS: Our data suggest that the provision of thyroglossal surgery is being consolidated in Scotland by speciality and that ENT surgeons are providing this service in the majority of cases.

Low sputum MMP-9/TIMP ratio is associated with airway narrowing in smokers with asthma.

Asthmatic smokers have poor symptom control and accelerated decline in lung function. A reduced ratio of matrix metalloproteinase (MMP)-9/tissue inhibitors of metalloproteinases (TIMPs) in nonsmokers with asthma has been implicated in airway remodelling. We tested the hypothesis that sputum MMP-9 activity/TIMPs ratios are reduced in smokers compared with never-smokers with asthma and are associated with reduced lung function and altered computed tomography (CT) measures of airway wall dimensions. Lung function, airway dimensions by CT, and induced sputum concentrations (and activity) of MMP-9 and TIMP-1 and -2 were measured in 81 asthmatics and 43 healthy subjects (smokers and never-smokers). Respiratory epithelial MMP9 and TIMP mRNA was quantified in 31 severe asthmatics and 32 healthy controls. Sputum MMP-9 activity/TIMP-1 and TIMP-2 ratios, and nasal epithelial MMP9/TIMP1 and MMP9/TIMP2 expression ratios were reduced in smokers with asthma compared with never-smokers with asthma. Low sputum ratios in asthmatic smokers were associated with reduced post-bronchodilator forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity ratio and segmental airway lumen area. The association of a low sputum MMP-9 activity/TIMP-1 ratio with persistent airflow obstruction and reduced CT airway lumen area in smokers with asthma may indicate that an imbalance of MMP-9 and TIMPs contributes to structural changes to the airways in this group.

Do high-speed drills generate high-frequency noise in mastoid surgery?

BACKGROUND: The introduction of increasingly high speed drills for mastoid surgery has heightened the concern that cochlea damage may occur in both the operated and nonoperated ear. It has been observed clinically that this damage could be associated with frequencies above 8,000 Hz and that, to observe these changes, high-frequency audiometry should be performed. Previous studies have investigated noise transmission to the cochlea at frequencies below 4,000 Hz only. There having been, until recently, limitations to the equipment available to measure higher frequencies. OBJECTIVE: To define the characteristics of noise transmitted to the cochlea during drilling of temporal bone, specifically in the higher frequency ranges up to 20,000 Hz. METHODS: Cleaned temporal bones were fitted with 3 mutually perpendicular accelerometers, capable of measuring frequencies in the range 500 to 20,000 Hz. The system was calibrated using a Kamplex Audio Traveller AA220 pure tone audiometer, and accelerometer outputs were recorded on a personal computer at a sampling frequency of 102.4 kHz per channel. The magnitude of the noise transmitted to the cochlea was determined for a range of burrs. RESULTS: Maximum transmission of sound was 108 dBA at 4,000 Hz using a 6.5-mm burr on the cortical mastoid bone. The average results showed that the sound transmission tailed off at the higher frequencies dropping to 84 dBA at 8,000 Hz and 40 dBA at 16,000 Hz. CONCLUSION: The high-frequency hearing reduction noted in patients after mastoid surgery was shown not to be due to excessive high-frequency noise generated by drilling.