Insertion of six different supraglottic airway devices whilst wearing chemical, biological, radiation, nuclear-personal protective equipment: a manikin study.

Six different supraglottic airway devices: Combitube™, laryngeal mask airway, intubating laryngeal mask airway (Fastrach™), i-gel™, Laryngeal Tube™ and Pro-Seal™ laryngeal mask airway were assessed by 58 paramedic students for speed and ease of insertion in a manikin, whilst wearing either chemical, biological, radiation, nuclear-personal protective equipment (CBRN-PPE) or a standard uniform. All devices took significantly longer to insert when wearing CBRN-PPE compared with standard uniform (p < 0.001). In standard uniform, insertion time was shorter than 45 s in 90% of attempts for all devices except the Combitube, for which 90% of attempts were completed by 53 s. Whilst wearing CBRN-PPE the i-gel was the fastest device to insert with a mean (SD (95% CI)) insertion time of 19 (8 (17-21))s, p < 0.001, with the Combitube the slowest with mean (65 (23 (59-71))s. Wearing of CBRN-PPE has a negative impact on supraglottic airway insertion time.

Brine-driven destruction of clay minerals in Gale crater, Mars.

Mars' sedimentary rock record preserves information on geological (and potential astrobiological) processes that occurred on the planet billions of years ago. The Curiosity rover is exploring the lower reaches of Mount Sharp, in Gale crater on Mars. A traverse from Vera Rubin ridge to Glen Torridon has allowed Curiosity to examine a lateral transect of rock strata laid down in a martian lake ~3.5 billion years ago. We report spatial differences in the mineralogy of time-equivalent sedimentary rocks <400 meters apart. These differences indicate localized infiltration of silica-poor brines, generated during deposition of overlying magnesium sulfate-bearing strata. We propose that destabilization of silicate minerals driven by silica-poor brines (rarely observed on Earth) was widespread on ancient Mars, because sulfate deposits are globally distributed.

Evidence for Multiple Diagenetic Episodes in Ancient Fluvial-Lacustrine Sedimentary Rocks in Gale Crater, Mars.

The Curiosity rover's exploration of rocks and soils in Gale crater has provided diverse geochemical and mineralogical data sets, underscoring the complex geological history of the region. We report the crystalline, clay mineral, and amorphous phase distributions of four Gale crater rocks from an 80-m stratigraphic interval. The mineralogy of the four samples is strongly influenced by aqueous alteration processes, including variations in water chemistries, redox, pH, and temperature. Localized hydrothermal events are evidenced by gray hematite and maturation of amorphous SiO2 to opal-CT. Low-temperature diagenetic events are associated with fluctuating lake levels, evaporative events, and groundwater infiltration. Among all mudstones analyzed in Gale crater, the diversity in diagenetic processes is primarily captured by the mineralogy and X-ray amorphous chemistry of the drilled rocks. Variations indicate a transition from magnetite to hematite and an increase in matrix-associated sulfates suggesting intensifying influence from oxic, diagenetic fluids upsection. Furthermore, diagenetic fluid pathways are shown to be strongly affected by unconformities and sedimentary transitions, as evidenced by the intensity of alteration inferred from the mineralogy of sediments sampled adjacent to stratigraphic contacts.

Does prehospital thrombolysis increase the proportion of patients who have an aborted myocardial infarction?

BACKGROUND: An "aborted" myocardial infarction is defined as an acute coronary syndrome where there is rapid resolution of existing ST segment elevation associated with a rise in creatine kinase (CK) less than twice the upper limit of normal or a small troponin release compatible with minimal myocyte necrosis. Previous research has shown that earlier thrombolysis is associated with a higher rate of aborted infarction. It is also known that prehospital thrombolysis reduces the pain-to-needle time. AIM: To test the hypothesis that prehospital thrombolysis is associated with a higher incidence of aborted infarction in a UK setting. METHODS: A retrospective analysis was performed for all patients given prehospital thrombolysis in the Avon sector catchment area of the Great Western Ambulance Service and Frimley Park Hospital between April 2004 and October 2006. The control group were patients given in-hospital thrombolysis at Frenchay Hospital or Frimley Park Hospital over the same period. Data reporting 12 h troponin levels, call-to-needle time, pain-to-needle time, door-to-needle time and incidence of aborted infarction were collected. RESULTS: Of the patients receiving prehospital thrombolysis, 69% had a pain-to-needle time of 2 h or less compared with 40.4% of patients receiving in-hospital thrombolysis (p<0.001). The overall incidence of aborted infarction was 16.5%. Of those with aborted infarction for whom pain-to-needle times were available, 54% had a pain-to-needle time of <2 h. Despite the difference in pain-to-needle times in favour of prehospital thrombolysis, there was no difference in the incidence of aborted myocardial infarction between the prehospital thrombolysis cohort and the in-hospital cohort, with 18.2% of in-hospital patients having a troponin I level <0.5 ng/ml compared with 11.8% of the prehospital cohort (p = 0.124). CONCLUSION: Although prehospital thrombolysis improved pain-to-needle time and a shorter pain-to-needle time increased the incidence of aborted infarction, prehospital thrombolysis was not associated with an increase in the proportion of aborted myocardial infarctions. Further work is required to understand this unexpected finding.

Is there still a place for emergency department thrombolysis following the introduction of the amended Joint Royal Colleges Ambulance Liaison Committee criteria for thrombolysis?

OBJECTIVE: To apply the current (2004) and the amended (2006) Joint Royal Colleges Ambulance Liaison Committee (JRCALC) criteria for paramedic initiated thrombolysis to all patients who received thrombolytic treatment in an emergency department (ED) to determine if the amendments increase the proportion suitable for paramedic initiated thrombolysis. DESIGN: Retrospective descriptive analysis. METHOD: The ED clinical notes, ambulance clinical record and the first recorded ECG (ED or ambulance) of all patients thrombolysed in the ED during a 12 month period were reviewed against the previous JRCALC guidelines (2004) and the amended JRCALC guidelines (2006) for thrombolysis. RESULTS: Using the JRCALC guidelines (2004), 26 of the 147 patients (17.7%) were eligible for paramedic initiated thrombolysis. Using the JRCALC guidelines (2006), this increased to 41 (27.9%). This difference was statistically significant (McNemar's I2 test with 1 degree of freedom = 15.00; p<0.001). The change to the blood pressure, age and pulse rate parameters has increased the percentage eligible for paramedic initiated thrombolysis by 10.2% (95% confidence interval 4.6% to 15.8%). CONCLUSION: The amended JRCALC guidelines (2006) for paramedic initiated thrombolysis have successfully increased the proportion of patients suitable for prehospital thrombolysis by approximately 10%, although the ED retains an important role in the provision of prompt thrombolytic treatment for a proportion of patients.

Toxins in the characterization of potassium channels.

Several recently characterized toxins (apamin, charybdotoxin, dendrotoxin and noxiustoxin) are proving invaluable for establishing what kinds of potassium channel are expressed in neurones, and what the roles of the channels might be.

What percentages of patients are suitable for prehospital thrombolysis?

OBJECTIVE: To apply the Joint Royal College Ambulance Liaison Committee (JRCALC) checklist to patients who were deemed eligible for thrombolytic therapy on arrival in an Accident & Emergency Department (A&E) to determine the proportion suitable for prehospital thrombolysis. DESIGN: Retrospective descriptive analysis. METHODS: The clinical notes of all patients thrombolysed in an A&E department in a year were reviewed against the JRCALC guidelines for prehospital thrombolysis. RESULTS: 14.2% of patients eligible for thrombolysis in a district general hospital were deemed suitable for prehospital thrombolysis according to the JRCALC criteria. The most common exclusion criteria were hyper/hypotension (50%), onset of symptoms (pain) >6 h previously (41.7%), or age >75 years (37%). Two or more contraindications to prehospital thrombolysis were present in 63.9% of patients. CONCLUSION: The JRCALC guidelines are an effective tool for identifying patients with potential contraindications to thrombolysis.

Differential inhibition of potassium currents in rat ventricular myocytes by capsaicin.

OBJECTIVE: Capsaicin is a pungent irritant present in peppers of the Capsicum family. Its major target of action is believed to be sensory neurones. Capsaicin has also been shown to prolong cardiac action potential in atrial muscle, perhaps by local release of calcitonin gene related peptide which in turn enhances inward calcium currents. However, capsaicin has been shown to inhibit K+ current in neurones. Since such an action could contribute to action potential prolonging activity of capsaicin in heart, the aim of the study was to examine the effects of capsaicin on cardiac K+ currents. METHODS: Ionic currents and action potentials were examined in isolated adult rat ventricular myocytes using the whole cell variant of the patch clamp technique at 25 degrees C. RESULTS: Capsaicin (10 microM) increased the action potential duration (APD50) from 45 ms to 166 ms. This effect was associated with an inhibition of three distinct K+ currents. The decreasing rank order of potency was: transient outward K+ current (ITO, IC50 = 6.4 microM), a voltage dependent non-inactivating outward current (IK, IC = 11.5 microM), and the inward rectifier K+ current (IK1, IC50 = 46.9 microM). Capsaicin induced block of ITO was characterised by a decrease in the peak current amplitude and an increase in the rate of inactivation. The inactivation of ITO in the absence of capsaicin was well described by a single exponential [tau = 77 (SEM 2) ms at +40 mV, n = 10]. However, in the presence of 10 microM capsaicin inactivation was best described by the sum of two exponentials [tau FAST = 4.4(0.5) ms; tau SLOW = 92.4(3.0) ms, n = 10] with the fast component contributing 46(2)% of the total decay. A small but consistent hyperpolarising shift (approximately 3 mV) in the steady state voltage dependence of inactivation of ITO was induced by 10 microM capsaicin. Capsaicin had no effect on the rate of ITO recovery from inactivation (tau = 49 ms and 48 ms for control and drug respectively). The capsaicin analogue, resiniferatoxin, which as an irritant is up to 10(4)-fold more potent than capsaicin, had no effect on any of the K+ currents when present at concentrations of up to 10 microM. In contrast another capsaicin analogue, zingerone (30 microM) blocked ITO by 52(12)% and IK by 35%. CONCLUSIONS: Capsaicin produces a prolongation of the rat ventricular action potential, an effect which is associated with inhibition of potassium currents.

Characterisation of transient outward current in young human atrial myocytes.

OBJECTIVE: The aim was to characterise the development of the transient outward current (Ito) in atrial myocytes of infants and children. METHODS: Whole cell voltage clamp was used to study outward currents in enzymatically isolated atrial myocytes from infants and children ranging in age from 3 days to 13.2 years. RESULTS: A transient inactivating current characteristic of Ito was observed in 71 myocytes from 22 patients aged 3 days to 13.2 years, including a 10 day old infant born prematurely at 33 weeks gestation. There was no discernible developmental trend in Ito current density [10.74(SEM 0.65) pA.pF-1 at +40 mV, n = 71 cells from 22 patients] or voltage dependence of inactivation, newborn values being similar to those in older children, and in adults reported elsewhere. A developmental reduction in total outward current density was attributable entirely to diminution of the non-inactivating steady state current component. The Ito time course of inactivation showed an apparent maturational evolution, with the youngest infants having slightly but significantly slower inactivation kinetics. The kinetics of Ito recovery from inactivation were well described by a single exponential model with no appreciable developmental trend in time course. CONCLUSIONS: Ito is expressed in human atrial myocytes from early infancy and does not show significant developmental changes in current density. The relative contribution of Ito to myocyte repolarisation might increase with age as a result of diminution in the non-inactivating current component. There is an apparent slight maturational acceleration in the time course of Ito inactivation but not in recovery from inactivation, perhaps excluding the latter as a mechanism for the previously reported functional unavailability of Ito in young human atrial muscle.

Identification of two toxins from scorpion (Leiurus quinquestriatus) venom which block distinct classes of calcium-activated potassium channel.

Two polypeptide toxins from scorpion (Leiurus quinquestriatus) venom which block distinct classes of calcium-activated potassium channels have been identified and partially purified. One toxin, at 50-100 ng/ml, blocks apamin-sensitive potassium fluxes in hepatocytes and inhibits [125I]monoiodoapamin binding. The other, more basic, toxin blocks apamin-insensitive potassium fluxes in erythrocytes at 200 ng/ml and, to our knowledge, is the first toxin shown to block the erythrocyte calcium-activated potassium channel with high affinity. The possible co-identity of this latter toxin with charybdotoxin is discussed.

Dequalinium: a potent inhibitor of apamin-sensitive K+ channels in hepatocytes and of nicotinic responses in skeletal muscle.

The bisquaternary compound dequalinium has been tested for its ability to inhibit the loss of K+ which angiotensin II causes in guinea-pig hepatocytes and which occurs through apamin-sensitive Ca(2+)-activated K+ (SKCa) channels. Dequalinium blocked angiotensin II-evoked K+ loss with an IC50 of 1.5 +/- 0.1 microM and also inhibited 125I-monoiodoapamin binding with a KI of 1.1 +/- 0.1 microM. It is the most active non-peptide SKCa blocker so far described. The neuromuscular blocking agent vecuronium was also tested, and proved to be considerably less effective (IC50, 4.5 +/- 0.3 microM; KI, 3.6 +/- 0.5 microM). Dequalinium was also examined for its actions at nicotinic receptors in skeletal muscle and was found to be a potent, non-competitive antagonist of carbachol contractions of the frog rectus abdominis. In the frog cutaneous pectoris muscle, end-plate depolarizations induced by carbachol became smaller and more transient in the presence of dequalinium at 10 nM. However, contractions of the frog sartorius and rat diaphragm in response to nerve stimulation were inhibited only by concentrations > 1 microM. These apparently discrepant effects of dequalinium on nicotinic responses could be explained either by open channel block of slow onset or by 'stabilization' of the desensitized state of the receptor. The potency of dequalinium will make it a useful agent for the study of nicotinic receptors as well as of SKCa channels.

Palytoxin induces a relatively non-selective cation permeability in frog sciatic nerve which can be inhibited by cardiac glycosides.

The effect of palytoxin (PTX) on compound resting potential and compound action potential of frog sciatic nerve was studied using the sucrose-gap technique. PTX irreversibly depolarized the compound resting potential and reduced the amplitude of the compound action potential. PTX evoked a marked depolarization when extracellular Na+ was replaced by Li+, Cs+ and the organic cations methylammonium, hydroxylammonium, and methylhydroxylammonium but not by tetramethylammonium, tetraethylammonium, choline or the divalent cations, Ca2+ and Ba2+. The maintained depolarization was not sensitive to inhibition by saxitoxin (300 nM) or procaine (10 mM). The depolarization was inhibited by ouabain or cymarin but not by the aglycon, strophanthidin. However, strophanthidin did antagonize the inhibitory action of cymarin which suggests that PTX and cardiac glycosides do not share an identical binding site but there may be some overlap. We conclude that in frog sciatic nerve, PTX interacts with the (Na+-K+) pump to induce the opening or formation of a relatively non-selective cation pore within or near the pump protein.

Relocation of the elderly.

In this article, the author reviews 78 studies addressing the relocation of the elderly. He begins by defining the four major forms of relocation and describing the trends in the current health care marketplace precipitating relocation events. Next, he reviews the major findings of studies assessing the potential negative and positive outcomes of relocation. These outcomes include changes in mortality rates, morbidity, and psychological or social changes. In addition, factors associated with successful relocation are presented. Finally, the primary contribution of this article is that the author assesses the strengths and limitations of this prior literature and combines the research he reviews in an analytic model. This model helps show some opportunities for future research in the relocation of the elderly.

Physical restraints in nursing homes: a review of the literature since the Nursing Home Reform Act of 1987.

The use of physical restraints is one of the most negative features of nursing home care. Their use significantly affects the quality of life of residents. In an attempt to limit the use of restraints, the Nursing Home Reform Act (NHRA) of 1987 contained provisions regulating their use. In this article, the authors review the literature on the use and consequences of physical restraints in nursing homes since the passage of the NHRA. First, they describe the history behind the use of restraints and define what is considered to be a physical restraint. Second, they examine the four most common justifications for restraint use. Third, they describe the incidence and prevalence of restraint use. Fourth, they address demographic and clinical characteristics of residents that have been found to be associated with restraint use. Fifth, they examine negative outcomes of restraining residents. Finally, they describe alternatives to using restraints.

Advance care planning in nursing homes: pre- and post-Patient Self-Determination Act.

OBJECTIVES: (1) To identify resident and organizational factors associated with the use of advance care plans pre- and post-implementation of the Patient Self-Determination Act (PSDA), and (2) to identify changes (pre- and post-implementation of the PSDA) in the relationship between these factors and the use of advance care plans. DESIGN: Complex, multistage cluster sampling. SETTING: Ten states were selected for variation in geographic location, Medicaid reimbursement rate, and average staffing patterns. Participants were 4,215 nursing home residents in 268 facilities. PRINCIPAL FINDINGS: Seventeen resident and organizational factors were associated with the use of do-not-resuscitate (DNR) orders in 1990, and 12 resident and organizational factors were associated with their use in 1993. Five factors showed a significant change from 1990 to 1993: activities of daily living (ADL) scores, race, cognitive performance scale (CPS) scores, full-time equivalent (FTE) nurse aides per resident, and bed size. Ten resident and organizational factors were associated with use of do-not-hospitalize (DNH) orders in 1990 and six resident and organizational factors were associated with DNH orders in 1993. Four factors showed a significant change from 1990 to 1993: legal guardian, FTE LPNs per resident, Medicaid census, and forprofit ownership. Five resident and organizational factors were associated with the use of living wills in 1990 and seven resident and organizational factors were associated with the use of living wills in 1993. Four factors showed a significant change from 1990 to 1993: ADL scores, race, length of stay, and for-profit ownership. CONCLUSION: The results indicate that the PSDA may have been successful in increasing the use of advance care plans and in changing the types of residents who use advance care plans. However, they also show that the use of advance care plans is associated with organizational characteristics, indicating that some types of facilities may be more willing and able to address the PSDA mandates.

Organizational and environmental factors associated with nursing home participation in managed care.

OBJECTIVE: To develop and test a model, based on resource dependence theory, that identifies the organizational and environmental characteristics associated with nursing home participation in managed care. DATA SOURCES AND STUDY SETTING: Data for statistical analysis derived from a survey of Directors of Nursing in a sample of nursing homes in eight states (n = 308). These data were merged with data from the On-line Survey Certification and Reporting System, the Medicare Managed Care State/County Data File, and the 1995 Area Resource File. STUDY DESIGN: Since the dependent variable is dichotomous, the logistic procedure was used to fit the regression. The analysis was weighted using SUDAAN. FINDINGS: Participation in a provider network, higher proportions of resident care covered by Medicare, providing IV therapy, greater availability of RNs and physical therapists, and Medicare HMO market penetration are associated with a greater likelihood of having a managed care contract. CONCLUSION: As more Medicare recipients enroll in HMOs, nursing home involvement in managed care is likely to increase. Interorganizational linkages enhance the likelihood of managed care participation. Nursing homes interested in managed care should consider upgrading staffing and providing at least some subacute services.

Should ward nurses be using automatic external defibrillators as first responders to improve the outcome from cardiac arrest? A systematic review of the primary research.

INTRODUCTION: The outcome from in-hospital cardiac arrest has improved little since the implementation of cardiopulmonary resuscitation 40 years ago. Early defibrillation improves survival following ventricular fibrillation and pulseless ventricular tachycardia. The emergence of automatic external defibrillators and advisory defibrillators has been heralded as the answer to defibrillation delays in-hospital. AIM: To locate and evaluate the evidence supporting automatic external defibrillator use in-hospital on general wards. METHOD: A systematic review of indexed and grey literature to identify primary research. RESULTS: Fifteen in-hospital automatic external defibrillator studies were located, five met the inclusion criteria. CONCLUSIONS: There is limited primary research evaluating automatic external defibrillators in-hospital. Manual defibrillators remain the most commonly used device for in-hospital defibrillation. Automated external defibrillators offer an alternative to manual defibrillation providing they have a screen and manual override capability, and the technology for pacing is close to hand. For in-hospital automatic external defibrillator programmes to be effective a change in nursing philosophy must occur, and defibrillation must become an expected rather than an extended nursing role.

Administrator turnover and quality of care in nursing homes.

PURPOSE OF THE STUDY: In this article, I examine the association between turnover of nursing home administrators and five important quality of care outcomes. DESIGN AND METHODS: The data came from a survey of 420 nursing facilities and the 1999 On-line Survey, Certification, and Reporting System. Using multivariate logistic regression analyses, I looked at the effects of turnover of administrators in nursing homes belonging to chain organizations and in nursing homes not belonging to chain organizations. RESULTS: I found the average annual turnover rate of administrators to be 43%. The multivariate logistic regression analyses show that in nursing homes belonging to chains, administrator turnover is associated with a higher than average proportion of residents who were catheterized, had pressure ulcers, and were given psychoactive drugs and with a higher than average number of quality-of-care deficiencies. In nursing homes not belonging to chains I found that turnover of administrators is associated with a higher than average proportion of residents who were restrained, were catheterized, had pressure ulcers, and were given psychoactive drugs. IMPLICATIONS: There is a need to improve understanding of how and why better outcomes are achieved in some nursing homes. This investigation serves to focus attention on nursing home administrators. I believe this study provides preliminary evidence that the turnover of administrators may have an important association with quality of care in nursing homes.

Innovation in nursing homes: which facilities are the early adopters?

PURPOSE: This study examined organizational and market factors associated with nursing homes that are most likely to be early adopters of innovations. Early adopter institutions, defined as the first 20% of facilities to adopt an innovation, are important because they subsequently facilitate the diffusion of innovations to others in the industry. DESIGN AND METHODS: Two groups of innovations were examined, special care units and subacute care services. I used discrete-time logistic regression analysis and nationally representative data from 13,162 facilities at risk of being early adopters of innovations during twelve 6-month intervals from 1992 to 1997. RESULTS: Organizational factors that increase the likelihood of early innovation adoption are larger bed size, chain membership, and high levels of private-pay residents. Four market factors that increase the likelihood of early innovation adoption are: a retrospective Medicaid reimbursement methodology, a more competitive environment, higher average income in the county, and a higher number of hospital beds in the county. IMPLICATIONS: This analysis shows that organizational and market characteristics of nursing homes affect their propensity toward early adoption of innovations. Some of the results may be useful for nursing home administrators and policy makers attempting to promote innovation.

Characteristics of nursing homes that are restraint free.

Using nationally representative data from the On-line Survey and Certification of Automated Records (OSCAR) and the Area Resource File (ARF), comprising 15,074 nursing homes, the differences between restraint free and non-restraint free nursing homes were examined. Restraint free nursing homes were found more likely to have residents with less ADL deficiencies and lower average numbers of residents who were bowel or bladder incontinent. They were more likely to be not-for-profit, smaller, low occupancy facilities that did not belong to nursing home chains, and were located in urban and more competitive areas. With regard to staffing factors, restraint free facilities had a richer mix of nursing staff, although the total number of staff per resident did not differ. Restraint free facilities were likely to utilize more full-time equivalent (FTE) registered nurses (RNs) per resident, but less FTE nurse aides and licensed practical nurses (LPNs) per resident. Psychoactive drug use rates did not differ between the types of homes.