Effectiveness of cricoid pressure in preventing gastric aspiration during rapid sequence intubation in the emergency department: study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Cricoid pressure is considered to be the gold standard means of preventing aspiration of gastric content during Rapid Sequence Intubation (RSI). Its effectiveness has only been demonstrated in cadaveric studies and case reports. No randomised controlled trials comparing the incidence of gastric aspiration following emergent RSI, with or without cricoid pressure, have been performed. If improperly applied, cricoid pressure increases risk to the patient. The clinical significance of aspiration in the emergency department is unknown. This randomised controlled trial aims to; 1. Compare the application of the 'ideal" amount of force (30 - 40 newtons) to standard, unmeasured cricoid pressure and 2. Determine the incidence of clinically defined aspiration syndromes following RSI using a fibrinogen degradation assay previously described.</p> <p>Methods/design</p> <p>212 patients requiring emergency intubation will be randomly allocated to either control (unmeasured cricoid pressure) or intervention groups (30 - 40 newtons cricoid pressure). The primary outcome is the rate of aspiration of gastric contents (determined by pepsin detection in the oropharyngeal/tracheal aspirates or treatment for aspiration pneumonitis up to 28 days post-intubation). Secondary outcomes are; correlation between aspiration and lowest pre-intubation Glasgow Coma Score, the relationship between detection of pepsin in trachea and development of aspiration syndromes, complications associated with intubation and grade of the view on direct largyngoscopy.</p> <p>Discussion</p> <p>The benefits and risks of cricoid pressure application will be scrutinised by comparison of the incidence of aspiration and difficult or failed intubations in each group. The role of cricoid pressure in RSI in the emergency department and the use of a pepsin detection as a predictor of clinical aspiration will be evaluated.</p> <p>Trial registration</p> <p>Australian New Zealand Clinical Trials Registry (ANZCTR): <a href="http://www.anzctr.org.au/ACTRN12611000587909.aspx">ACTRN12611000587909</a></p

Stress Measurements in ZrB₂-SiC Composites Using Raman Spectroscopy and Neutron Diffraction

Raman spectroscopy and neutron diffraction were used to study the stresses generated in zirconium diboride-silicon carbide (ZrB2-SiC) ceramics. Dense, hot pressed samples were prepared from ZrB2 containing 30 vol% α-SiC particles. Raman patterns were acquired from the dispersed SiC particulate phase within the composite and stress values were calculated to be 810 MPa. Neutron diffraction patterns were acquired for the ZrB2-SiC composite, as well as pure ZrB2 and SiC powders during cooling from ∼1800 °C to room temperature. A residual stress of 775 MPa was calculated as a function of temperature by comparing the lattice parameter values for ZrB2 and SiC within the composite to those of the individual powders. The temperature at which stresses began to accumulate on cooling was found to be ∼1400 °C based on observing the deviation in lattice parameters between pure powder samples and those of the composite

Measurement of Thermal Residual Stresses in ZrB₂-SiC Composites

Neutron diffraction, Raman spectroscopy, and x-ray diffraction were employed to measure the stresses generated in the ZrB2 matrix and SiC dispersed particulate phase in ZrB2-30 vol% SiC composites produced by hot pressing at 1900 °C. Neutron diffraction measurements indicated that stresses begin to accumulate at ∼1400 °C during cooling from the processing temperature and increased to 880 MPa compressive in the SiC phase and 450 MPa tensile in the ZrB2 phase at room temperature. Stresses measured via Raman spectroscopy revealed the stress in SiC particles on the surface of the composite was ∼390 MPa compressive, which is ∼40% of that measured in the bulk by neutron diffraction. Grazing incidence x-ray diffraction was performed to further characterize the stress state in SiC particles near the surface. Using this technique, an average compressive stress of 350 MPa was measured in the SiC phase, which is in good agreement with that measured by Raman spectroscopy

Reference intervals for non-fasting CVD lipids and inflammation markers in pregnant Indigenous Australian women

Indigenous Australians experience high rates of cardiovascular disease (CVD). The origins of CVD may commence during pregnancy, yet few serum reference values for CVD biomarkers exist specific to the pregnancy period. The Gomeroi gaaynggal research project is a program that undertakes research and provides some health services to pregnant Indigenous women. Three hundred and ninety-nine non-fasting samples provided by the study participants (206 pregnancies and 175 women) have been used to construct reference intervals for CVD biomarkers during this critical time. A pragmatic design was used, in that women were not excluded for the presence of chronic or acute health states. Percentile bands for non-linear relationships were constructed according to the methods of Wright and Royston (2008), using the xriml package in StataIC 13.1. Serum cholesterol, triglycerides, cystatin-C and alkaline phosphatase increased as gestational age progressed, with little change seen in high-sensitivity C-Reactive Protein and gamma glutamyl transferase. Values provided in the reference intervals are consistent with findings from other research projects. These reference intervals will form a basis with which future CVD biomarkers for pregnant Indigenous Australian women can be compared

Gomeroi gaaynggal: empowerment of Aboriginal communities to understand health implications of research in pregnancy

There is an increasing body of evidence indicating how critical good health in pregnancy is for both the short and long term health of an infant. When the Aboriginal community suffers such a high burden of poor health and reduced life expectancy, it is appropriate to look at improving the health of Aboriginal women throughout their pregnancy as a mechanism for ‘Closing the Gap’. Sadly, Aboriginal women are more than twice as likely to deliver their babies prematurely than non- Aboriginal women(14.3% versus 7.9% respectively) and with abnormally low birthweights (13.2% versus 6.1%). In all other measurable outcomes, Aboriginal infants fare poorly in their first twelve months with increased rates of foetal, neonatal and perinatal death