Incidence of sore throat in children following use of flexible laryngeal mask airways – impact of an introducer device

Background: Insertion of a flexible laryngeal mask airway (FLMA) is more difficult and therefore might result in a higher risk for trauma to the upper airway. To facilitate the insertion of FLMA, the use of an introducer device (Portex Limited, Hythe, Kent, UK) was promoted. However, the impact of the use of this device on the occurrence of postoperative sore throat is unknown. Methods: Four hundred children (3–21 years) undergoing elective ambulatory surgery were consecutively included in this study. In 196 cases, the FLMA was inserted using an introducer device. The FLMA cuff was then inflated and the pressure adjusted to below 60 cmH₂O (according to manufacturers guidelines) using a calibrated cuff manometer (Portex Limited). Three types of FLMA were available: FLMA classic, FLMA unique (both FLMA PacMed, Richmond, Victoria, Australia) and FLMA ProBreathe (Well Lead Medical Co Ltd., Hualong, Guangzhou, China). Prior to discharge, patients’ pain was assessed using an age appropriate scale. Results: Thirteen children (3.3%) developed sore throat, two (0.5%) sore neck and three (0.75%) sore jaw. Of those that developed sore throat, seven had a FLMA inserted with an introducer, six without an introducer. Using a laryngeal mask airways (LMA) with a polyvinyl chloride (PVC), surface was associated with a higher risk for sore throat compared with an LMA with a silicone surface (P = 0.0002). Conclusion: In this study with controlled low cuff pressures, the incidence of sore throat was low. The use of an introducer device did not affect the rate of sore throat.     

A degeneration-based hypothesis for interpreting fibrillar changes in the osteoarthritic cartilage matrix

The collagen fibrillar architectures in the general matrix of cartilage slices removed from both normal and osteoarthritic femoral heads were examined by both differential interference light microscopy and scanning electron microscopy. Whereas the normal general matrix contained a finely differentiated pseudo-random weave of fibrils developed from an interconnected array of radial elements, the osteoarthritic general matrix was characterised by the presence of structurally distinct regions consisting of strongly aligned radial bundles of fibrils and associated intense tangles or 'knotted' features. Simple structural models were developed to explore possible transformation structures based on two different types of interconnectivity in the three-dimensional fibrillar network. These models support the hypothesis that the distinctive ultrastructural features of the osteoarthritic general matrix can develop as a consequence of largely passive degradative changes occurring in the fibrillar weave originally present in the normal matrix. This could, in principle, occur independently of any new structure that might develop as a consequence of any upregulation of collagen associated with the osteoarthritic process.     

Suppressor macrophages in Trypanosoma brucei infection: nitric oxide is related to both suppressive activity and lifespan in vivo

African trypanosome infections cause immunosuppression in both experimental rodent and natural hosts. One characteristic of this is an eliciting of suppressor macrophages which results in an unresponsiveness in lymphocytes. Macrophages from Trypanosoma brucei-infected mice have previously been shown to produce high levels of nitric oxide (NO). Using model systems based on in vivo macrophage transfer and drug cure, we have sought to determine the relationship between NO and suppressed lymphocyte responses. Peritoneal macrophages from T. brucei-infected mice inhibited the Concanavalin A (Con-A) response of spleen cells from syngeneic recipients 3–4 days after transfer in vivo due to the activity of suppressor macrophages. When macrophage NO synthesis was inhibited either in vitro or in vivo the suppressive effects were partially abrogated. These data provide evidence of a role for NO in mediating immunosuppression during murine T. brucei infection. Suppression in spleens of mice receiving suppressor macrophages was transient, with total recovery of spleen cell mitogen responses six days after transfer. Suppression and recovery was found to coincide with the presence or absence (respectively) of donor macrophages in recipient spleens. When T. brucei-infected mice were treated with a curative dose of a trypanocide there followed a recovery of lymphocyte responsiveness after a period of 4–5 days, and this directly correlated with a reduction of macrophage NO synthesis to control levels both in vivo and in vitro. The apparent loss of suppressor macrophage activity after 4–6 days in both drug cured animals and recipients of macrophage transfer was shown to be due to NO-mediated apoptosis of these cells.     

Shadowland: general practitioners and the treatment of opiate-abusing patients

A number of calls have recently been made for general practitioners to become more closely involved in the treatment of opiate abusing patients. At present, however, very little is known of the sorts of problems general practitioners will face in working within what is held to be a very difficult area. The research reported in this paper aimed to explore the experience of a group of general practitioners currently being consulted by such patients. A combination of enhanced records and semi-structured interviews were used to collect detailed information on 50 consultations with opiate abusers. It is revealed that these doctors were experiencing a good deal of difficulty in sustaining a therapeutic role for themselves in relation to these patients. The nature of these difficulties, and their basis, are examined and recommendations are made as to how these difficulties may be resolved in the future.     

Microarousals in patients with sleep apnoea/hypopnoea syndrome

SUMMARY Upper airway obstructions during sleep cause recurrent brief awakenings or microarousals. Standard criteria exist for sleep and respiratory event scoring, however, there are different definitions currently used to score microarousals. We therefore compared three definitions of microarousal (ranging from 1.5-3 s in duration) and one of awakening (> 15 s). We examined their occurrence at the termination of apnoeas and hypopnoeas and their correlation with daytime sleepiness in patients with sleep apnoea/hypopnoea syndrome (SAHS). Sixty-three patients (aged 49, SD 10) had overnight polysomnography, multiple sleep latency tests (MSLT) and Epworth Sleepiness Scales (ESS). There were significantly more microarousals by any definition than there were awakenings (P<0.001) and there were more 1.5 s than 3 s microarousals (P<0.001). Significantly more apnoeas and hypopnoeas were terminated by 1.5 s microarousals (83% and 81%) than by 3 s microarousals (75%) (all P<0.001). Apnoea/hypopnoea index (AHI) correlated significantly with objective daytime sleepiness (p = -0.30, P<0.01). There were weakly significant relationships between all three microarousal definitions (-0.24<P< -0.22, 0.03<P<0.04) and objective daytime sleepiness. None of the arousal definitions correlated with Epworth Sleepiness Scales scores. These results suggest that although 1.5 s microarousals are found at the end of more respiratory events, relationships between 3 and 1.5 s definitions, and daytime sleepiness are similar. This indicates that any of the three microarousal definitions can be used for visual assessment of sleep fragmentation.