Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies.

Across multiple disciplines undertaking airway management globally, preventable episodes of unrecognised oesophageal intubation result in profound hypoxaemia, brain injury and death. These events occur in the hands of both inexperienced and experienced practitioners. Current evidence shows that unrecognised oesophageal intubation occurs sufficiently frequently to be a major concern and to merit a co-ordinated approach to address it. Harm from unrecognised oesophageal intubation is avoidable through reducing the rate of oesophageal intubation, combined with prompt detection and immediate action when it occurs. The detection of 'sustained exhaled carbon dioxide' using waveform capnography is the mainstay for excluding oesophageal placement of an intended tracheal tube. Tube removal should be the default response when sustained exhaled carbon dioxide cannot be detected. If default tube removal is considered dangerous, urgent exclusion of oesophageal intubation using valid alternative techniques is indicated, in parallel with evaluation of other causes of inability to detect carbon dioxide. The tube should be removed if timely restoration of sustained exhaled carbon dioxide cannot be achieved. In addition to technical interventions, strategies are required to address cognitive biases and the deterioration of individual and team performance in stressful situations, to which all practitioners are vulnerable. These guidelines provide recommendations for preventing unrecognised oesophageal intubation that are relevant to all airway practitioners independent of geography, clinical location, discipline or patient type.

Project for Universal Management of Airways - part 1: concept and methods.

Multiple professional groups and societies worldwide have produced airway management guidelines. These are typically targeted at the process of tracheal intubation by a particular provider group in a restricted category of patients and reflect practice preferences in a particular geographical region. The existence of multiple distinct guidelines for some (but not other) closely related circumstances, increases complexity and may obscure the underlying principles that are common to all of them. This has the potential to increase cognitive load; promote the grouping of ideas in silos; impair teamwork; and ultimately compromise patient care. Development of a single set of airway management guidelines that can be applied across and beyond these domains may improve implementation; promote standardisation; and facilitate collaboration between airway practitioners from diverse backgrounds. A global multidisciplinary group of both airway operators and assistants was assembled. Over a 3-year period, a review of the existing airway guidelines and multiple reviews of the primary literature were combined with a structured process for determining expert consensus. Any discrepancies between these were analysed and reconciled. Where evidence in the literature was lacking, recommendations were made by expert consensus. Using the above process, a set of evidence-based airway management guidelines was developed in consultation with airway practitioners from a broad spectrum of disciplines and geographical locations. While consistent with the recommendations of the existing English language guidelines, these universal guidelines also incorporate the most recent concepts in airway management as well as statements on areas not widely addressed by the existing guidelines. The recommendations will be published in four parts that respectively address: airway evaluation; airway strategy; airway rescue and communication of airway outcomes. Together, these universal guidelines will provide a single, comprehensive approach to airway management that can be consistently applied by airway practitioners globally, independent of their clinical background or the circumstances in which airway management occurs.

Alkaliphilic Bacillus species show potential application in concrete crack repair by virtue of rapid spore production and germination then extracellular calcite formation.

AIMS: Characterization of alkaliphilic Bacillus species for spore production and germination and calcite formation as a prelude to investigate their potential in microcrack remediation in concrete. METHODS AND RESULTS: Conditions, extent and timing of endospore production was determined by dark-field light microscopy; germination induction and kinetics were assessed by combining reduction in optical density with formation of refractile bodies by phase-contrast microscopy. Bacillus pseudofirmus was selected from several species as the most suitable isolate. Levels and timing of calcium carbonate precipitated in vitro by B. pseudofirmus were evaluated by atomic absorption spectroscopy and structural identity confirmed as calcite and aragonite by Raman spectroscopy and FTIR. The isolate produced copious spores that germinated rapidly in the presence of germinants l-alanine, inosine and NaCl. Bacterial cells produced CaCO3 crystals in microcracks and the resulting occlusion markedly restricted water ingress. CONCLUSIONS: By virtue of rapid spore production and germination, calcium carbonate formation in vitro and in situ, leading to sealing of microcracks, B. pseudofirmus shows clear potential for remediation of concrete on a commercial scale. SIGNIFICANCE AND IMPACT OF THE STUDY: Microbial sealing of microcracks should become a practicable and sustainable means of increasing concrete durability.

Forces generated by Macintosh and GlideScope® laryngoscopes in four airway-training manikins.

We measured forces generated by Macintosh and GlideScope(®) laryngoscope blades during airway intubation by 16 participants in four manikins: Laerdal(®) SimMan; TruCorp AirSim™ Advance; Laerdal(®) Airway Management Trainer; and Ambu(®) Airway Man. Both laryngoscopes generated the least force in the Laerdal Airway Management Trainer and the most in the Ambu Airway Man. The respective median (IQR [range]) forces generated by the Macintosh blade were 2 (1-4 [1-7]) N vs 9 (7-13 [5-16]) N, p = 0.00004, with peak forces 9 (5-11 [3-16]) N vs 18 (12-22 [3-31]) N, p = 0.0004. The respective average and peak forces generated by the GlideScope blade were 1 (1-2 [0-3]) N vs 4 (3-5 [2-6]) N, p = 0.00001, and 4 (2-7 [0-12]) N vs 7 (4-9 [3-18]) N, p = 0.054.

Measurement of forces applied during Macintosh direct laryngoscopy compared with GlideScope® videolaryngoscopy.

Laryngoscopy can induce stress responses that may be harmful in susceptible patients. We directly measured the force applied to the base of the tongue as a surrogate for the stress response. Force measurements were obtained using three FlexiForce Sensors(®) (Tekscan Inc, Boston, MA, USA) attached along the concave surface of each laryngoscope blade. Twenty-four 24 adult patients of ASA physical status 1-2 were studied. After induction of anaesthesia and neuromuscular blockade, laryngoscopy and tracheal intubation was performed using either a Macintosh or a GlideScope(®) (Verathon, Bothell, WA, USA) laryngoscope. Complete data were available for 23 patients. Compared with the Macintosh, we observed lower median (IQR [range]) peak force (9 (5-13 [3-25]) N vs 20 (14-28 [4-41]) N; p = 0.0001), average force (5 (3-7 [2-19]) N vs 11 (6-16 [1-24]) N; p = 0.0003) and impulse force (98 (42-151 [26-444]) Ns vs 150 (93-207 [17-509]) Ns; p = 0.017) with the GlideScope. Our study shows that the peak lifting force on the base of the tongue during laryngoscopy is less with the GlideScope videolaryngoscope compared with the Macintosh laryngoscope.

A comparison of the forces applied to a manikin during laryngoscopy with the GlideScope and Macintosh laryngoscopes.

The force applied during laryngoscopy can cause local tissue trauma and can induce cardiovascular responses and cervical spine movement in susceptible patients. Previous studies have identified numerous operator and patient factors that influence the amount of force applied during intubation. There are few studies evaluating the effect of different laryngoscope blades and no study involving video laryngoscopes. In this study we measured the forces using two laryngoscopic techniques. Three FlexiForce Sensors (A201-25, Tekscan, Boston, MA, USA) were attached to the concave blade surface of a Macintosh and a GlideScope laryngoscope. Experienced anaesthetists performed Macintosh and GlideScope intubations on the Laerdal Airway Management Trainer manikin. Compared to Macintosh intubations, the GlideScope intubations had equal or superior views of the glottis with 55%, 58% and 66% lower median peak, average and impulse forces applied to the tongue base. The distal sensor registered the most force in both devices and the force distribution pattern was similar between the devices. The findings suggest that the GlideScope requires less force for similar or better laryngoscopic views, at least in a manikin model.

Depressive symptoms in early pregnancy disrupt attentional processing of infant emotion.

BACKGROUND: Growing evidence suggests that perinatal depression is associated with disrupted mother-infant interactions and poor infant outcomes. Antenatal depression may play a key role in this cycle by disrupting the development of a maternal response to infant stimuli. The current study therefore investigated the impact of depressive symptoms on the basic cognitive processing of infant stimuli at the beginning of pregnancy. METHOD: A total of 101 women were recruited by community midwives and tested at an average gestation of 11 weeks. An established computerized paradigm measured women's ability to disengage attention from infant and adult faces displaying negative positive and neutral emotions. Depressive symptoms were measured using a computerized interview (the Clinical Interview Schedule). RESULTS: The effect of infant emotion on women's ability to disengage from infant faces was found to be influenced by depressive symptoms. Non-depressed pregnant women took longer to disengage attention from distressed compared with non-distressed infant faces. This bias was not, however, seen in women experiencing depressive symptoms. There was a difference of -53 (s.d.=0.7) ms (95% confidence interval -90 to -14, p=0.007) between those with and without depressive symptoms in this measure of attentional bias towards distressed infant faces. CONCLUSIONS: Our results suggest that depressive symptoms are already associated with differential attentional processing of infant emotion at the very beginning of childbearing. The findings have potential implications for our understanding of the impact of depressive symptoms during pregnancy on the developing mother-infant relationship.

Measurements of plasma oxycodone, noroxycodone and oxymorphone levels in a patient with bilateral nephrectomy who is undergoing haemodialysis.

The use of opioid analgesics in renal dysfunction is potentially problematic and many patients with end stage renal disease are unable to tolerate these medications. A greater understanding of the pharmacokinetics of opioid analgesics is vital in informing safe and effective practice. Using pharmacokinetic analysis, this case study demonstrates for the first time that oxycodone and its metabolites are removed by haemodialysis. As such, care should be taken when using oxycodone in patients undergoing haemodialysis.

Changes in (14)C-labeled 2-deoxyglucose brain uptake from nickel-induced epileptic activity.

Unilateral epidural applications of nickel solution to motor cortex were followed in about 1 h by contralateral forelimb myoclonus. In rats which displayed frequent myoclonal jerking during the 45-min 2-deoxyglucose (2-DG) uptake and clearing period, autoradiographic analysis showed that glucose utilization at the nickel implant site was greater in the supragranular and infragranular layers than in the granular layer (in normal cortex, activity is greatest in the granular layer), and was also greater in the substantia nigra and other subcortical centers. The same cortical and most of the subcortical changes in 2-DG uptake were also observed when metabolic activity was assessed 1 h after myoclonus had stopped, indicating that it may not have been the seizure activity itself that had altered metabolic activity, but some process engendered by the seizures - possibly a tissue response to excitotoxic damage. In fact, rats which displayed infrequent myoclonus showed negligible increases in cortical and subcortical uptake. These results do not support an earlier claim that increased glucose consumption is the metabolic signature of the interictal activity produced by seizure-inducing metals. Indeed, the findings raise the possibility that tissue damage is responsible for interictal hypermetabolism when it is observed in animal models of epilepsy.

Characterization of SNP1, a cell wall-degrading trypsin, produced during infection by Stagonospora nodorum.

Stagonospora (= Septoria) nodorum when grown in liquid culture with wheat cell walls as the sole carbon and nitrogen source secretes numerous extracellular depolymerases, including a rapidly produced, alkaline, trypsin-like protease (SNP1). The enzyme was purified 417-fold by cation exchange chromatography and has a molecular mass of 25 kDa on sodium dodecyl sulfate gels, pI 8.7, and pH optimum of 8.5. It cleaved peptide bonds on the carboxyl side of lysine or arginine, was strongly inhibited by the trypsin inhibitors aprotinin and leupeptin and weakly by phenylmethylsulfonyl fluoride, and its activity was stimulated by calcium. SNP1 has the characteristic, conserved, fungal, trypsin N terminus. Polymerase chain reaction (PCR) primers based on this sequence and the conserved trypsin active site were used to amplify a DNA fragment that facilitated isolation of the corresponding genomic clone from a lambda library of S. nodorum. The full-length sequence confirmed its identity as a trypsin-like protease containing the N-terminal sequence of the previously purified enzyme. Infected leaf tissue contained a protease, not present in controls, that coeluted with the fungal trypsin from cation exchange, and had properties (pI and inhibitor characteristics) similar to those of the fungal trypsin. SNP1 expression in planta was detected by Northern (RNA) blotting, reverse transcription PCR, and green fluorescent protein confocal microscopy. SNP1 released hydroxyproline from wheat cell walls. The release of hydroxyproline, together with its early expression in planta, suggests that SNP1 participates in the degradation of host cell walls during infection.