Incidence of severe critical events in paediatric anaesthesia in the United Kingdom: secondary analysis of the anaesthesia practice in children observational trial (APRICOT study).

The anaesthesia practice in children observational trial of 31,127 patients in 261 European hospitals revealed a high (5.2%) incidence of severe critical events in the peri-operative period and wide variability in practice. A sub-analysis of the UK data was undertaken to investigate differences compared with the non-UK cohort in the incidence and nature of peri-operative severe critical events and to attempt to identify areas for quality improvement. In the UK cohort of 7040 paediatric patients from 43 hospitals, the overall incidence of peri-operative severe critical events was lower than in the non-UK cohort (3.3%, 95%CI: 2.9-3.8 vs. 5.8%, 95%CI: 5.5-6.1, RR 0.57, p < 0.001). There was a lower rate of bronchospasm (RR 0.22, 95%CI: 0.14-0.33; p < 0.001), stridor (RR 0.42, 95%CI: 0.28-0.65; p < 0.001) and cardiovascular instability (RR 0.69, 95%CI: 0.55-0.86; p = 0.001) than in the non-UK cohort. The proportion of sicker patients where less experienced teams were managing care was lower in the UK than in the non-UK cohort (10.4% vs. 20.4% of the ASA physical status 3 and 9% vs. 12.9% of the ASA physical status 4 patients). Differences in work-load between centres did not affect the incidence and outcomes of severe critical events when stratified for age and ASA physical status. The lower incidence of cardiovascular and respiratory complications could be partly attributed to more experienced dedicated paediatric anaesthesia providers managing the higher risk patients in the UK. Areas for quality improvement include: standardisation of serious critical event definitions; increased reporting; development of evidence-based protocols for management of serious critical events; development and rational use of paediatric peri-operative risk assessment scores; implementation of current best practice in provision of competent paediatric anaesthesia services in Europe; development of specific training in the management of severe peri-operative critical events; and implementation of systems for ensuring maintenance of skills.

The Universal Anaesthesia Machine (UAM): assessment of a new anaesthesia workstation built with global health in mind.

The Universal Anaesthesia Machine has been developed as a complete anaesthesia workstation for use in low- and middle-income countries, where the provision of safe general anaesthesia is often compromised by unreliable supply of electricity and anaesthetic gases. We performed a functional and clinical assessment of this anaesthetic machine, with particular reference to novel features and functioning in the intended environment. The Universal Anaesthesia Machine was found to be reliable, safe and consistent across a range of tests during targeted functional testing.

Comparison of work of breathing using drawover and continuous flow anaesthetic breathing systems in children.

We compared the work of breathing under general anaesthesia in children using drawover and continuous flow anaesthetic systems. A pilot study was conducted in four children weighing > 20 kg in whom it would usually be considered appropriate to use breathing systems designed for adult anaesthesia. The pilot study compared work of breathing using the Mapleson D breathing system and the Triservice Anaesthetic Apparatus (TSAA). Work of breathing was calculated using the modified Campbell technique that calculates work using a pressure volume loop derived from oesophageal pressure and airway gas volume measurements. We found no difference in the work of breathing when comparing the Mapleson D and the TSAA in children > 20 kg. Following completion of the pilot study, we conducted a study on 10 children weighing between 10 and 20 kg comparing work of breathing using the Mapleson F breathing system and the TSAA. We found no significant difference in the work of breathing between the Mapleson F and the TSAA for these children. The TSAA can therefore be recommended for use down to a lower weight limit of 10 kg.

Drawbacks of pushovers.

Some military anaesthetists have started to use the Oxford Miniature Vaporiser in a pushover configuration with the Triservice anaesthetic apparatus. This vaporiser performs identically in the pushover and drawover configurations with the Cape TC 50 ventilator. We tested the Oxford Miniature Vaporiser with three other ventilators and found variable performance. When used in the pushover configuration with the Laerdal bag at normal minute volumes, the Oxford Miniature Vaporiser delivers a higher than set output.

The CompPAC and PortaPAC portable ventilators bench tests and field experience.

The military and some civilian rescue agencies have a requirement for portable ventilators in the anaesthetic, resuscitation and pre-hospital environment. This paper describes two new portable ventilators specifically designed to satisfy the military requirement for lightweight, robust and versatile equipment which can also be used in a contaminated environment.

An in vitro model of angiogenesis: basic features.

This report describes a model of angiogenesis which develops in admixtures (co-cultures) of human umbilical vein endothelial cells (HUVEC) and human diploid fibroblasts of dermal origin from adult patients. The system does not require the addition of further growth factors other than those normally present in endothelial growth medium (EGM), nor matrix proteins, and cell growth and proliferation are allowed to occur in a standard low (2%) concentration of fetal calf serum. Angiogenesis was specifically stimulated in response to vascular endothelial growth factor (VEGF), resulting in an increased development of structures resembling a microvasculature bed. Alternatively, angiogenesis was inhibited by addition of an excess of neutralising anti-VEGF antibodies, and the anti-angiogenic drugs such as suramin. We briefly show that stimulatory and inhibitory activities can be easily and quickly quantified by image analysis. Tubule formation was confirmed by confocal and electron microscopy, and the development and disposition of these structures within the co-cultures has been analysed immunochemically to show expression of specific endothelial cell determinants, such as PECAM-1. On this and a number of other criteria, the findings validate this in vitro process as a model of in vivo angiogenesis that can be quantified to assay stimulatory and inhibitory agents, signals and drugs.

An asthmatic weaned from a ventilator using a laryngeal mask.

A case is described in which a patient was unable to be weaned from ventilatory support whilst the trachea remained intubated. She was successfully weaned using a laryngeal mask.

Subdural block--further points.

An obstetric epidural performed for analgesia showed a changing pattern of neurological block. The original features suggestive of a subdural block were complicated when aspiration of cerebrospinal fluid from the catheter became possible. Subsequent management as a continuous subarachnoid catheter allowed delivery.

Plasma very low density lipoproteins contain a single molecule of apolipoprotein B.

Rat and human very low density lipoproteins (VLDL) were fractionated by zonal ultracentrifugation, yielding sharply defined fractions with narrow sedimentation limits. Sedimentation coefficients for the individual fractions were determined at two densities with the analytical ultracentrifuge, and the results were analyzed to yield buoyant densities and molecular weights for the particles in each fraction. For the rat lipoproteins, the weight concentrations of triglycerides, cholesterol, phospholipid, and protein were determined for each fraction, and their molar concentrations of apolipoprotein B were measured with a radioimmunoassay. For the human lipoproteins the corresponding values were taken from Patsch et al. (Patsch, W., J. R. Patsch, G. M. Kostner, S. Sailer, and H. Braunsteiner. 1978. Isolation of subfractions of human very low density lipoproteins by zonal ultracentrifugation. J. Biol. Chem. 253:4911-4915). From these data, a ratio of the number of apoB peptides to the number of lipoprotein particles was calculated for each fraction. This ratio was close to 1 for all VLDL fractions, ranging in particle diameter from about 40 to 80 mm and 30 to 50 mm, respectively, for rat and human VLDL. The majority rat VLDL contain B-48 rather than B-100 as their (single) apoB peptide. Based on these data, we proposed that only a single copy of B-48 is required for VLDL assembly in rat liver, unless nascent hepatic VLDL contain additional apoB peptides which are uniformly lost from the plasma VLDL particles when they are analyzed.