Simultaneous Large Optical and Piezoelectric Effects Induced by Domain Reconfiguration Related to Ferroelectric Phase Transitions

Electrical switching of ferroelectric domains and subsequent domain wall motion promotes strong piezoelectric activity, however, light scatters at refractive index discontinuities such as those found at domain wall boundaries. Thus, simultaneously achieving large piezoelectric effect and high optical transmissivity is generally deemed infeasible. Here, it is demonstrated that the ferroelectric domains in perovskite Pb(In_1/2 Nb_1/2 )O₃ -Pb(Mg_1/3 Nb_2/3 )O₃ -PbTiO₃ domain-engineered crystals can be manipulated by electrical field and mechanical stress to reversibly and repeatably, with small hysteresis, transform the opaque polydomain structure into a highly transparent monodomain state. This control of optical properties can be achieved at very low electric fields (less than 1.5 kV cm^-1 ) and is accompanied by a large (>10 000 pm V^-1 ) piezoelectric coefficient that is superior to linear state-of-the-art materials by a factor of three or more. The coexistence of tunable optical transmissivity and high piezoelectricity paves the way for a new class of photonic devices.

Holistic approach supporting mental wellbeing of people in enforced quarantine in South Australia during the COVID-19 pandemic

OBJECTIVES

To report the experience of quarantine for international arrivals to South Australia requiring quarantine in a medi-hotel setting during the COVID-19 pandemic and to describe the range of evidence-based support services to mitigate the mental health impacts of quarantine.

METHODS

A range of services targeted at physical and mental wellbeing were provided. Data from 533 adult respondents out of 721 passengers were included. The Kessler 10 was used to measure psychological distress at two time points.

RESULTS

About 7.1% of respondents reported psychological distress at time one, reduced to 2.4% at time two. There was no significant difference in psychological distress by gender at either time point. The mean K10 score at time one was 13.6 (standard deviation=5.2) and the mean score at time two was 11.5 (standard deviation=3.1), with a significant reduction in mean scores (p<0.001) between the two time points.

CONCLUSIONS

The level of psychological stress in repatriated Australians was low at arrival and improved further at the time of release from quarantine. Implications for public health: A collaborative multi-sector approach to provide support services for individuals in quarantine can mitigate risks to mental wellbeing.

Direct-Write of Nanoscale Domains with Tunable Metamagnetic Order in FeRh Thin Films

We have directly written nanoscale patterns of magnetic ordering in FeRh films using focused helium-ion beam irradiation. By varying the dose, we pattern arrays with metamagnetic transition temperatures that range from the as-grown film temperature to below room temperature. We employ transmission electron microscopy, X-ray diffraction, and temperature-dependent transport measurements to characterize the as-grown film, and magneto-optic Kerr effect imaging to quantify the He⁺ irradiation-induced changes to the magnetic order. Moreover, we demonstrate temperature-dependent optical microscopy and conductive atomic force microscopy as indirect probes of the metamagnetic transition that are sensitive to the differences in dielectric properties and electrical conductivity, respectively, of FeRh in the antiferromagnetic (AF) and ferromagnetic (FM) states. Using density functional theory, we quantify strain- and defect-induced changes in spin-flip energy to understand their influence on the metamagnetic transition temperature. This work holds promise for in-plane AF-FM spintronic devices, by reducing the need for multiple patterning steps or different materials, and potentially eliminating interfacial polarization losses due to cross material interfacial spin scattering.

Association of chain of survival factors with out of hospital cardiac arrest survival in a region with low average population-density: a retrospective population-based cohort study

Background

Out of hospital cardiac arrest (OHCA) has an average global survival rate to discharge of 8%. Chain of survival factors are heavily time-dependant and optimization can increase survival. Regions with low population density encounter challeges in providing optimal OHCA care. Nova Scotia's average population density is 17.4 persons per square kilometer in compasiron to Toronto with 4334.4 person per square kilometer. OHCAs have been described well in large urban centers globally, however the characterization of OHCA chain of survival in low density populations is sparse.

Purpose

To describe chain of survival factors and identify characteristics of survivors and non-survivors among those treated by paramedics in a low average density provincial population.

Methods

This was a retrospective cohort study of OHCAs responded to by paramedics. All OHCA responses with a cardiac etiology in Nova Scotia, Canada were included. Exclusion criteria were non-cardiac cause arrests, those with “do not resuscitate” (DNR) directives and expected deaths. The paramedic electronic patient care record was reviewed for demographic, bystander, out of hospital treatment and operational characteristics. Primary outcome was survival to hospital discharge. Descriptive statistics were calculated to describe differences between survivorship using Prism 8.0 (San Diego, CA) with alpha=0.05 applying unpaired, Mann-Whitney tests.

Results

Of 1517 OHCA, 463 were excluded leaving 1054 OHCA. Of these, 478 (45.3%) were treated by paramedics and included in this analysis. Most were men (67.2%; n=274) with a mean age 66.8 (±16.4). A total of 7.1% (n=75) survived to discharge with 76% of survivors (n=58) discharged home. Survivors were more likely to present with ventricular fibrillation than non-survivors (42.7% vs. 19.6%). Survivors compared to non-survivors had significantly shorter paramedic response time (8.1 vs. 10.7 min, P&lt;0.001), paramedic time on scene (35.7 vs. 45.4 min, P=0.002), estimated time to paramedic defibrillation (13.2 vs 19.4 min, P&lt;0.001), and estimated time to return of spontaneous circulation (ROSC) (22.9 vs 31.9min, P&lt;0.001).

Conclusion

Links in the chain of survival are associated with survival from OHCA. OHCA survival is lower in the less densely populated province of Nova Scotia compared to studies in urban Canadian centers and worldwide. Our study is limited by the retrospective nature of data collection and lack of access to neurological outcomes. Even among survivors, EMS response is delayed compared to more densely populated centers. In Nova Scotia, longer paramedic response times are associated with decreased survival.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Maritime Heart Center

Beyond Gold: Spin-Coated Ti3 C2 -Based MXene Photodetectors

2D transition metal carbides, known as MXenes, are transparent when the samples are thin enough. They are also excellent electrical conductors with metal-like carrier concentrations. Herein, these characteristics are exploited to replace gold (Au) in GaAs photodetectors. By simply spin-coating transparent Ti₃ C₂ -based MXene electrodes from aqueous suspensions onto GaAs patterned with a photoresist and lifted off with acetone, photodetectors that outperform more standard Au electrodes are fabricated. Both the Au- and MXene-based devices show rectifying contacts with comparable Schottky barrier heights and internal electric fields. The latter, however, exhibit significantly higher responsivities and quantum efficiencies, with similar dark currents, hence showing better dynamic range and detectivity, and similar sub-nanosecond response speeds compared to the Au-based devices. The simple fabrication process is readily integratable into microelectronic, photonic-integrated circuits and silicon photonics processes, with a wide range of applications from optical sensing to light detection and ranging and telecommunications.

Oxidation of Monolayer WS2 in Ambient Is a Photoinduced Process

We have studied the ambient air oxidation of chemical vapor deposition (CVD) grown monolayers of the semiconducting transition metal dichalcogenide (S-TMD) WS₂ using optical microscopy, laser scanning confocal microscopy (LSCM), photoluminescence (PL) spectroscopy, and atomic force microscopy (AFM). Monolayer WS₂ exposed to ambient conditions in the presence of light (typical laboratory ambient light for weeks or typical PL spectroscopy map) exhibits damage due to oxidation which can be detected with the LSCM and AFM, though may not be evident in conventional optical microscopy due to poorer contrast and resolution. Additionally, this oxidation was not random and was correlated with "high-symmetry" high intensity edges and red-shifted areas in the PL spectroscopy map, areas thought to contain a higher concentration of sulfur vacancies. In contrast, samples kept in ambient and darkness showed no signs of oxidation for up to 10 months. Low-irradiance/fluence experiments showed that samples subjected to excitation energies at or above the trion excitation energy (532 nm/2.33 eV and 660 nm/1.88 eV) oxidized in as little as 7 days, even for irradiances and fluences 8 and 4 orders of magnitude lower (respectively) than previously reported. No significant oxidation was observed for 760 nm/1.63 eV light exposure, which lies below the trion excitation energy in WS₂. The strong wavelength dependence and apparent lack of irradiance dependence suggests that ambient oxidation of WS₂ is initiated by photon-mediated electronic band transitions, that is, photo-oxidation. These findings have important implications for prior, present, and future studies concerning S-TMDs measured, stored, or manipulated in ambient conditions.

Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model

Vanadium dioxide is a material that has a reversible metal-insulator phase change near 68 °C. To grow VO2 on a wide variety of substrates, with wafer-scale uniformity and angstrom level control of thickness, the method of atomic-layer deposition was chosen. This ALD process enables high-quality, low-temperature (≤150 °C) growth of ultrathin films (100-1000 Å) of VO2. For this demonstration, the VO2 films were grown on sapphire substrates. This low temperature growth technique produces mostly amorphous VO2 films. A subsequent anneal in an ultra-high vacuum chamber with a pressure of 7x10-4 Pa of ultra-high purity (99.999%) oxygen produced oriented, polycrystalline VO2 films. The crystallinity, phase, and strain of the VO2 were determined by Raman spectroscopy and X-ray diffraction, while the stoichiometry and impurity levels were determined by X-ray photoelectron spectroscopy, and finally the morphology was determined by atomic force microscopy. These data demonstrate the high-quality of the films grown by this technique. A model was created to fit to the data for VO2 in its metallic and insulating phases in the near infrared spectral region. The permittivity and refractive index of the ALD VO2 agreed well with the other fabrication methods in its insulating phase, but showed a difference in its metallic state. Finally, the analysis of the films' optical properties enabled the creation of a wavelength- and temperature-dependent model of the complex optical refractive index for developing VO2 as a tunable refractive index material.

Optical polarization of excitons and trions under continuous and pulsed excitation in single layers of WSe2

The potential for valleytronic operation has stimulated much interest in studying polarized emission from transition metal dichalcogenides. In most studies, however, little regard is given to the character of laser excitation. We measure the circularly polarized photoluminescence of WSe₂ monolayers as a function of excitation energy for both continuous-wave (cw) and pulsed laser excitation sources. Using cw excitation, the temperature dependence of the depolarization of the trion follows the same trend as that of the neutral exciton and involves collisional broadening. However, the polarization of the trion is nearly twice the polarization of the neutral exciton at low temperatures. When a pulsed laser with the same average fluence is used as the excitation source, the degrees of polarization become very similar, in stark contrast to the cw results. The difference in polarization behaviors is linked to the different amounts of energy deposited in the system during these measurements for similar average fluences. At a moderate fluence, pulsed excitation also has the potential to fundamentally alter the emission characteristics of WSe₂.

Understanding Variations in Circularly Polarized Photoluminescence in Monolayer Transition Metal Dichalcogenides

Monolayer transition metal dichalcogenides are promising materials for valleytronic operations. They exhibit two inequivalent valleys in the Brillouin zone, and the valley populations can be directly controlled and determined using circularly polarized optical excitation and emission. The photoluminescence polarization reflects the ratio of the two valley populations. A wide range of values for the degree of circularly polarized emission, P_circ, has been reported for monolayer WS₂, although the reasons for the disparity are unclear. Here, we optically populate one valley and measure P_circ to explore the valley population dynamics at room temperature in a large number of monolayer WS₂ samples synthesized via chemical vapor deposition. Under resonant excitation, P_circ ranges from 2 to 32%, and we observe a pronounced inverse relationship between photoluminescence (PL) intensity and P_circ. High-quality samples exhibiting strong PL and long exciton relaxation time exhibit a low degree of valley polarization, and vice versa. This behavior is also demonstrated in monolayer WSe₂ samples and transferred WS₂, indicating that this correlation may be more generally observed and account for the wide variations reported for P_circ. Time-resolved PL provides insight into the role of radiative and nonradiative contributions to the observed polarization. Short nonradiative lifetimes result in a higher measured polarization by limiting opportunity for depolarizing scattering events.

Energy Transfer Sensitization of Luminescent Gold Nanoclusters: More than Just the Classical Förster Mechanism

Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with three structurally/functionally-distinct donor classes including organic dyes, metal chelates and semiconductor quantum dots (QDs). Donor quenching was observed for every donor-acceptor pair although AuNC sensitization was only observed from metal-chelates and QDs. FRET theory dramatically underestimated the observed energy transfer while NSET-based damping models provided better fits but could not reproduce the experimental data. We consider additional factors including AuNC magnetic dipoles, density of excited-states, dephasing time, and enhanced intersystem crossing that can also influence ET. Cumulatively, data suggests that AuNC sensitization is not by classical FRET or NSET and we provide a simplified distance-independent ET model to fit such experimental data.

Performance enhancement of a GaAs detector with a vertical field and an embedded thin low-temperature grown layer

Low temperature growth of GaAs (LT-GaAs) near 200 °C results in a recombination lifetime of nearly 1 ps, compared with approximately 1 ns for regular temperature ∼600 °C grown GaAs (RT-GaAs), making it suitable for ultra high speed detection applications. However, LT-GaAs detectors usually suffer from low responsivity due to low carrier mobility. Here we report electro-optic sampling time response measurements of a detector that employs an AlGaAs heterojunction, a thin layer of LT-GaAs, a channel of RT-GaAs, and a vertical electric field that together facilitate collection of optically generated electrons while suppressing collection of lower mobility holes. Consequently, these devices have detection efficiency near that of RT-GaAs yet provide pulse widths nearly an order of magnitude faster—∼6 ps for a cathode-anode separation of 1.3 μm and ∼12 ps for distances more than 3 μm.

Evaluation of physician assistants in National Health Service Scotland

Physician assistants (PAs) have medical training and work supervised by a doctor. In 2006-2008 the Scottish Government piloted use of USA-trained PAs. The aim of the paper is to evaluate the impact and contribution made by PAs to delivering effective health care in National Health Service (NHS) Scotland. Mixed methods, longitudinally, including interviews, feedback forms and activity data collection. Data analysis used nVivo, SPSS and Excel. Participants were 15 USA-trained PAs, medical supervisors and team members, 20 patients, four NHS senior managers and three trade union representatives. Settings were four Scottish NHS Boards where PAs worked in primary care, out of hours clinics, emergency medicine, intermediate care and orthopaedics. Two minor patient safety issues arose. Patients were satisfied with PAs. Scope of practice did not replicate US working. Inability to prescribe was a hindrance. PAs tended to have longer consultations, but provided continuity and an educational resource. They were assessed to be mid-level practitioners approximating to nurse practitioner or generalist doctor. Valued features were generalism, medical background, confidence differential diagnosis and communication. Interviewees suggested PAs could fulfil roles currently filled by medical staff, potentially saving resources. In conclusion, there is potential for PAs to fulfil distinctive mid-level roles in the Scottish NHS adding value in continuity, communication and medical approach.

Improved optical pulse propagation in water using an evolutionary algorithm

Optical pulse propagation in water is experimentally investigated using an evolutionary algorithm (EA) to control the shape of an optical pulse. The transmission efficiency (ratio of output to input optical power) is maximized by searching the combined amplitude and phase space governing an optical pulse shaper. The transmission efficiency of each tested pulse is physically determined by experiment during the course of the optimization. Combining the EA with an experiment in this manner is a powerful means of improving some figure of merit because no analytical or computational model is required-we optimize directly given the physics of the experiment. In addition, the EA is capable of efficiently searching a large parameter space. Here, we demonstrate improved linear optical pulse propagation near 800nm. Our results demonstrate a pulse with a dramatically narrower bandwidth that coincides with a local absorption minimum (near 800 nm) implying that the transmission efficiency is dominated by water's absorption spectrum.

Green and ultraviolet pulse generation with a compact, fiber laser, chirped-pulse amplification system for aerosol fluorescence measurements

We use a compact chirped-pulse amplified system to harmonically generate ultrashort pulses for aerosol fluorescence measurements. The seed laser is a compact, all-normal dispersion, mode-locked Yb-doped fiber laser with a 1050 nm center wavelength operating at 41 MHz. Average powers of more than 1.2 W at 525 nm and 350 mW at 262 nm are generated with <500 fs pulse durations. The pulses are time-stretched with high-dispersion fiber, amplified by a high-power, large-mode-area fiber amplifier, and recompressed using a chirped volume holographic Bragg grating. The resulting high-peak-power pulses allow for highly efficient harmonic generation. We also demonstrate for the first time to our knowledge, the use of a mode-locked ultraviolet source to excite individual biological particles and other calibration particles in an inlet air flow as they pass through an optical chamber. The repetition rate is ideal for biofluorescence measurements as it allows faster sampling rates as well as the higher peak powers as compared to previously demonstrated Q-switched systems while maintaining a pulse period that is longer than the typical fluorescence lifetimes. Thus, the fluorescence excitation can be considered to be quasicontinuous and requires no external synchronization and triggering.

Bayesian estimation of weak material dispersion: theory and experiment

This work considers the estimation of dispersion in materials via an interferometric technique. At its core, the problem involves extracting the quadratic variation in phase over a range of wavelengths based on measured optical intensity. The estimation problem becomes extremely difficult for weakly dispersive materials where the quadratic nonlinearity is very small relative to the uncertainty inherent in experiment. This work provides a means of estimating dispersion in the face of such uncertainty. Specifically, we use a Markov Chain Monte Carlo implementation of Bayesian analysis to provide both the dispersion estimate and the associated confidence interval. The interplay between various system parameters and the size of the resulting confidence interval is discussed. The approach is then applied to several different experimental samples.

Broadband optical pulse scattering from a glass fiber

We report results of scattering measurements using femtosecond pulses to collect a wealth of information in a single experiment. Potential issues with particle scattering, such as variation in particle size, were avoided by using 9 and 50 microm diameter glass fibers. We first establish an angular scattering intensity baseline, and we show that the spectral width of very short pulses leads to smoothing of the angular scattering pattern, consistent with continuous broadband illumination. We then measure the angular scattering pattern from short pulses with a spectrometer and reveal an underlying spectral periodicity of broadband scattered light that is consistent with narrowband cw scattering. Our experimental results compare well with existing theory. We show that such two-dimensional experimental data and derived analytic solution can provide robust characterization of scattering objects even in the presence of noise.

Prevalence of Mycoplasma genitalium in health clinic attendees complaining of vaginal discharge in Bangladesh

The objective of the study was to determine the prevalence of Mycoplasma genitalium in a sample of health clinic attendees complaining of vaginal discharge. A subsample of 399 vaginal and cervical swabs was randomly selected from 2579 samples collected during a study to determine the causes of vaginal discharge in women attending primary health-care clinics in Dhaka, Bangladesh. Cervical samples were tested for M. genitalium by polymerase chain reaction. In addition, the samples were tested for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, bacterial vaginosis and candida. M. genitalium was detected in three samples (0.8%; 95% confidence interval: 0.00–1.6). The prevalence of C. trachomatis, N. gonorrhoeae T. vaginalis, bacterial vaginosis and candida was 1.3, 3.8, 8, 23.25 and 32.5%, respectively. Two women with M. genitalium were co-infected with T. vaginalis or candida. This is the first study to document the existence of M. genitalium in Bangladesh. Although the prevalence of this infection is low in the population tested, further research into this pathogen in other Bangladeshi populations is justified.

Verification of nose irradiation using orthovoltage x-ray beams

Determination of dose distributions from superficial and orthovoltage irradiations of basal cell carcinoma of the nose has been performed using a nose shaped phantom constructed from paraffin wax. EBT type radiochromic film was used for dose measurements. A 2 cm diameter 50 kVp anterior field was used to irradiate the nose phantom, with sheets of film placed at 7 mm, 14 mm and 23 mm physical depth. The percentage depth doses at these points were measured to be 84% +/- 1.6%, 66% +/- 2.7% and 50% +/- 1.2% respectively, compared to the expected percentage depth doses of 72%, 52% and 34%, measured in full scatter conditions. This discrepancy is believed to be due to the steep drop off at the sides of the nose phantom, resulting in reduced attenuation at the edges of the beam, which in turn results in an increase in the scatter contribution to the dose at depth on the central axis. Measured dose profiles from this technique showed a reasonably uniform distribution. A second technique using a 250 kVp tangent-like field to irradiate the tip of the nose was also tested. Radiochromic film was placed against the edges of the phantom for dose measurement. The dose at the surface was measured to be 27% +/- 1.5% less than the expected dose. It is believed that this discrepancy is due to a combination of the lack of backscatter from the phantom, and a small offset between the phantom and the treatment cone. Dose measurements and profiles showed that this technique results in a variation in dose across the treated volume of 7%. However, the difficulty in predicting the delivered dose prohibited it from clinical use.

Crisis management during anaesthesia: vascular access problems

BACKGROUND

In confronting an evolving crisis, the anaesthetist should consider the vascular catheter as a potential cause, abandoning assumptions that the device has been satisfactorily placed and is functioning correctly.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for vascular access problems, in the management of crises occurring in association with anaesthesia.

METHODS

The potential performance of a structured approach was evaluated for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS).

RESULTS

There were 128 incidents involving problems related to vascular access. The structured approach begins distally, checking the infusion device or fluid (12 incidents), moving proximally by way of the fluid giving line (10), the line deadspace (8), then the catheter/skin interface (65), and on to the peripheral vascular tree (3) and central venous space (23), and finally, the interface of the vascular access system and the attending staff (7). The approach was able to accommodate all the vascular access problems among the first 4000 incidents reported to AIMS.

CONCLUSION

The approach has potential as an easily remembered and applied clinical tool to lead to early resolution of vascular access problems occurring during anaesthesia.

Crisis management during anaesthesia: hypertension

BACKGROUND

Hypertension occurs commonly during anaesthesia and is usually promptly and appropriately treated by anaesthetists. However, its recognition is dependent on correctly functioning and calibrated monitors. If it is not diagnosed and/or promptly corrected, it has the potential to cause significant morbidity and even mortality.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK" supplemented by a specific sub-algorithm for the management of hypertension occurring in association with anaesthesia.

METHODS

The potential performance of this approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

There were 70 reports of intraoperative hypertension among the first 4000 incidents reported to AIMS. Drug related causes accounted for 59% of all incidents. It was considered that, properly applied, this structured approach would have led to a quicker and/or better resolution of the problem in 21% of the cases.

CONCLUSION

Once hypertension is identified and confirmed, its rapid control by the careful use of a volatile anaesthetic agent, intravenous opioids, or rapidly acting antihypertensives will usually avoid serious morbidity. If hypertension is unresponsive to the treatment recommended in the relevant sub-algorithm, an unusual cause such as phaeochromocytoma, carcinoid syndrome, or thyroid storm should be considered.

Crisis management during anaesthesia: recovering from a crisis

Preventing harm to the patient is the priority during a crisis. After a major incident, and especially when a patient has been harmed, there are a number of matters to be addressed: the ongoing care of the patient; documentation of the incident; investigation of the root causes; completion of reports; interviews with the patient and/or the next of kin, together with apologies and expression of regret; updates and ongoing support for friends and relatives; a word of thanks to the staff involved for their assistance; formal debriefing of staff for quality assurance and possibly ongoing support and a separate debriefing for psychological purposes; ensuring that the recommendations of the root cause analysis are carried out; or, failing that, that the issues are logged on a risk register. The extent and depth of the follow up protocol depends on what, if any, harm may have been done. This may constitute completion of an incident report; notification of an equipment failure to a federal regulatory authority; arranging consultations with a mental health professional to manage psychological sequelae (especially following an awareness episode); follow up during weeks of intensive care treatment; or, when a death has occurred, a full medico-legal and/or coronial set of procedures. A precis is appended in an action card format.

Crisis management during anaesthesia: anaphylaxis and allergy

BACKGROUND

Anaphylactic and anaphylactoid reactions during anaesthesia are a major cause for concern for anaesthetists. However, as individual practitioners encounter such events so rarely, the rapidity with which the diagnosis is made and appropriate management instituted varies considerably.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for anaphylaxis, in the management of severe allergic reactions occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual performance as reported by the anaesthetists involved.

RESULTS

There were 148 allergic reactions among the first 4000 incidents reported to AIMS. It was considered that, properly applied, the structured approach would have led to a quicker and/or better resolution of the problem in 30% of cases, and would not have caused harm had it been applied in all of them.

CONCLUSION

An increased awareness of the diverse clinical manifestations of allergy seen in anaesthetic practice, together with the adoption of a structured approach to management should improve and standardise the treatment and improve follow up of patients suspected of having suffered a significant allergic reaction under anaesthesia.

Crisis management during anaesthesia: myocardial ischaemia and infarction

BACKGROUND

Myocardial ischaemia and infarction are significant perioperative complications which are associated with poor patient outcome. Anaesthetic practice should therefore focus, particularly in the at risk patient, on their prevention, their accurate detection, on the identification of precipitating factors, and on rapid effective management.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK" supplemented by a specific sub-algorithm for myocardial ischaemia and infarction in the management of myocardial ischaemia and/or infarction occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

Of the 125 incidents retrieved from the 4000 reports, 40 (1%) were considered to demonstrate myocardial infarction or ischaemia. The use of the structured approach described in this paper would have led to appropriate management in 90% of cases, with the remaining 10% requiring other sub-algorithms. It was considered that the application of this structured approach would have led to earlier recognition and/or better management of the problem in 45% of cases.

CONCLUSION

Close and continuous monitoring of patients at risk of myocardial ischaemia during anaesthesia is necessary, using optimal ECG lead configurations, but sensitivity of this monitoring is not 100%. Coronary vasodilatation with glyceryl trinitrate (GTN) should not be withheld when indicated and the early use of beta blocking drugs should be considered even with normal blood pressures and heart rates.

Experimental measurements of solitary pulse characteristics from an all-normal-dispersion Yb-doped fiber laser

We demonstrate a solitary pulse output from an 8.3-MHz mode-locked Yb-doped fiber laser, operating entirely in the normal dispersion regime. The typical output hyperbolic-secant pulses have a 14-ps pulse width and a 1.2-mW average output power. The spectrum has steep band edges with a 6.1-nm width and a tunable center wavelength between 1050 and 1080 nm. Using a frequency-resolved optical gating setup, we show that the pulse intensity and phase profiles are consistent with a chirped soliton. Energy quantization is observed, thus demonstrating the non-parabolic nature of these pulses. The laser output is compressed to near the transform limit (approximately 430 fs).

High-energy saturable absorber mode-locked fiber laser system

We demonstrate a mode-locked erbium-doped fiber laser with a 1-microm InGaAs saturable absorber that produces 84-ps, 1-nJ transform-limited pulses. Measurements of the InGaAs multiple quantum well revealed a slow saturable absorber that is useful for passive mode locking. Optical fiber was added to extend the cavity and vary the repetition rate from 51 kHz to 5.4 MHz. The narrow spectral width of the laser output (<0.04 nm) permits amplification to 0.2 microJ/pulse with minimal pulse broadening. Pulse energies as large as 1.7 microJ can be achieved with pulse widths of <330 ps. Average powers of 0.5 W at megahertz repetition rates are demonstrated.

Physician knowledge of the diagnosis and management of Rocky Mountain spotted fever: Mississippi, 2002

Rocky Mountain spotted fever (RMSF), a tick-borne illness that has its highest incidence in the south central and southeastern United States, is often a diagnostic challenge, as patients frequently present with nonspecific symptoms during the early stages of illness. RMSF has a high case fatality rate among untreated individuals, and the median time from onset of symptoms to death is only eight days, making early recognition and treatment of RMSF crucial. In two Mississippi public health districts, 148 primary care physicians were randomly selected and mailed surveys regarding RMSF diagnosis, treatment, and prevention. Eighty-four of the 148 (57%) physicians responded. Responses from different specialties and different health districts were compared using chi square statistics. Almost all (99%) physicians correctly identified doxycycline as the antibiotic agent of choice for treating adults and adolescents. However, only 21% of family practice physicians, and 25% of emergency medicine physicians correctly identified the antibiotic of choice for treating children with RMSF. Twenty-three percent of physicians responded that waiting for the development of a rash before prescribing antibiotics is an appropriate treatment strategy. The current standard of care-doxycycline as the agent of choice among children 8 years of age or younger with suspected RMSF-has not been effectively communicated to all physicians caring for children. Also, many physicians are not familiar with the rationale underlying initiation of antibiotic therapy prior to the development of rash in patients with suspected RMSF. Continuing education efforts should focus on antibiotic selection in pediatric patients and initiation of therapy prior to the onset of rash in appropriate patients.

Smallpox nursing in Britain, Part II: Nursing care and nurse training

Part I of this paper attempted to justify the need for this research for historical purposes, that is, to fill a gap in the history of nursing, and sought to raise awareness of possible bioterrorist activity with the smallpox virus. The disease process, now unfamiliar to most nurses, was briefly described, and reference was made to the change from a predominantly childhood to adult disease. The gradual removal of patients from home to hospital or other institutions was considered and the diverse nature of their attendants was discussed. Smallpox was then explained from two nursing perspectives: firstly, the concept of smallpox as a nurses' disease. In this, it was universally acknowledged that only nurses could make some difference to a patient's survival and minimal disfigurement, but secondly, in so doing, they put their own lives at risk. Examples were given of nurses who succumbed. Finally, some central and local government measures which endeavoured to prevent the spread of the disease were outlined. Part II focuses specifically on nursing care and training as it is through this medium that knowledge may be passed from earlier to present day nurses.

A new short practical quality of life questionnaire for use in head and neck oncology outpatient clinics

A new short questionnaire to assess the quality of life of head and neck patients has been designed at the University of Liverpool Head and Neck Oncology Department. The questionnaire is short, simple and can be easily completed by a patient whilst in the waiting room before consultation. It is filled in 6 months after completion of treatment and shows very good correlation with the standard long exhaustive questionnaires that are difficult to complete on every patient in a busy National Health Service clinic. The University of Liverpool questionnaire provides a simple score from 0%-100% which should prove valuable in the assessment of quality of care and help with decisions regarding treatment options in head and neck cancer patients.

Ultrafast, all-silicon light modulator

An ultrafast, all-silicon light-intensity modulator is proposed. The carrier-refraction effect is used to modulate the refractive index of silicon. An electric-field-induced Bragg reflector on a silicon-on-insulator optical waveguide efficiently converts the small modulation of the index of refraction into light-intensity modulation. A modulator with 300-microm interaction length is expected to have a modulation depth of ~40% with 5-V bias. Being based on free-carrier depletion, this modulator is expected to have a bandwidth limited only by the RC time constant, which is calculated for a sample device to be ~40 GHz.

The Australian Incident Monitoring Study. The "wrong drug" problem in anaesthesia: an analysis of 2000 incident reports

Amongst the first 2000 incidents reported to the Australian Incident Monitoring Study, there were 144 incidents in which the "wrong drug" was nearly or actually administered to a patient. Thirty-three percent of the incidents involved ampoules and just over 40% syringes; in over half of the latter the syringes were of the same size, and also, in over half, they were correctly labelled. In 81% of the 144 incidents the "wrong drug" was actually given. This was more common with syringes (93%) than ampoules (58%). Thus the most common error was actually giving the wrong drug from a correctly labelled syringe. The most common drug involved was a muscle relaxant in both ampoule and syringe incidents. In 74% of all reports, there was the potential for serious harm to the patient; however no deaths were reported. Factors which contributed significantly to the incidents were similar appearance, inattention and haste. "Failure of communication" was a significant factor in syringe incidents when two or more staff were involved. The only significant factor which minimised the outcome was rechecking of the syringe or drug ampoule before giving the drug. Strategies suggested to address the "wrong drug" problem include education of staff about the nature of the problem and the mechanisms involved; colour coding of selected drug classes for both ampoules and syringes; the use of standardised drug storage, layout and selection protocols; having a drawing up and labelling convention; and the use of checking protocols.

The Australian Incident Monitoring Study. The pulse oximeter: applications and limitations--an analysis of 2000 incident reports

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the pulse oximeter. Of these 184 (9%) were first detected by a pulse oximeter and there were a further 177 (9%) in which desaturation was recorded. Of the 1256 incidents which occurred in association with general anaesthesia 48% were "human detected" and 52% "monitor detected". The pulse oximeter was ranked first and detected 27% of these monitor detected incidents; this figure would have been over 40% if an oximeter had always been used and its more informative modulated pulse tone relied upon instead of that of the "bleep" of the ECG. The pulse oximeter is the "front-line" monitor for endobronchial intubation, the fourth most common incident in association with general anaesthesia (it detected 87% of the 76 cases in which it was in use). It also played an invaluable role as a "back-up" monitor in 40 life-threatening situations in which "front-line" monitors (e.g. oxygen analyser, low pressure alarm, capnograph) were either not in use, were being used incorrectly or failed. Other situations detected, in order of frequency of detection, were: circuit disconnection, circuit leak, desaturation (severe shunt), oesophageal intubation, aspiration and/or regurgitation, pulmonary oedema, endotracheal tube obstruction, severe hypotension, failure of oxygen delivery, hypoxic gas mixture, hypoventilation, anaphylaxis, air embolism, bronchospasm, malignant hyperthermia, and tension pneumothorax.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. Errors, incidents and accidents in anaesthetic practice

Human error is a pervasive and normal part of everyday life and is of interest to the anaesthetist because errors may lead to accidents. Definitions of, and the relationships between, errors, incidents and accidents are provided as the basis to this introduction to the psychology of human error in the context of the work of the anaesthetist. Examples are drawn from the Australian Incident Monitoring Study (AIMS). An argument is put forward for the use of contemporaneous incident reporting (eliciting relevant contextual information as well as details of use to cognitive psychologists), rather than the use of accident investigation after the event (with the inherent problems of scant information, altered perception and outcome bias). A classification of errors is provided. "Active" errors may be classified into knowledge-based, rule-based, skill-based and technical errors. Different strategies are required for the prevention of each type and it may now be useful to place more emphasis in anaesthetic practice on categories to which little attention has been directed in the past. "Latent" errors make an enormous contribution to problems in anaesthesia and several categories are discussed (e.g. environment, physiological state, equipment, work practices, personnel training, social and cultural factors). An approach is provided for the prevention and management of errors, incidents and accidents which allows clinical problems to be categorized, the relative importance of various contributing factors to be established, and appropriate preventative strategies to be devised and implemented on the basis of priorities determined from the AIMS data. Accidents cannot be abolished; however, an understanding of the factors underlying them can lead to the rational direction of resources and effort to prevent them and minimise their effects.

The Australian Incident Monitoring Study. Blood pressure monitoring--applications and limitations: an analysis of 2000 incident reports

Of the first 2000 incidents reported to the Australian Incident Monitoring Study, 1256 occurred in relation to general anaesthesia and 81 of the latter were first detected by blood pressure (BP) monitoring. A further 25 incidents not associated with general anaesthesia were first detected by blood pressure monitoring, giving a total of 106. In the monitor detection of incidents in relation to general anaesthesia, BP monitoring ranked fourth after oximetry, capnography and low pressure alarms. On the other hand, 38 incidents in which the problem was primarily one of significant change in BP were first detected by means other than the BP monitor (20 clinically, 12 by pulse oximetry and 6 by ECG). Early detection rates of hypotension were 60% for invasive methods, 40% for automated non-invasive (NIBP) devices and 30% for manual sphygmomanometry. There were 21 reports of BP monitor "failure"; the 11 of these which occurred with NIBPs involved unexplained false "low" or "high" readings and failure to detect profound hypotension, and led to considerable morbidity and at least one death. The 10 cases of invasive monitoring failure were predominantly due to mains power loss, hardware breakage or operator error. In a theoretical analysis of the 1256 GA incidents, it was considered that on its own, BP monitoring would have detected 919 (73%), but in the vast majority, by the time this detection has occurred, potential organ damage could not be excluded. It is recommended that BP be measured at regular intervals dictated by clinical requirements (usually at least every five minutes).(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. Clinical anaphylaxis: an analysis of 2000 incident reports

There were 57 reports of possible allergic reactions in the perioperative period in the first 2000 incidents reported to the Australian Incident Monitoring Study. These were examined and classified with respect to presentation, clinical course, agents implicated and management strategies employed. Reactions were graded as to probability of allergic aetiology and severity of systemic disturbance. Two deaths were reported. A method of determining an "allergy score" was devised as an indication of which reactions may be most deserving of further investigation.

The Australian Incident Monitoring Study. The electrocardiograph: applications and limitations--an analysis of 2000 incident reports

The first 2000 incidents reported to the Australian Incident Monitoring Study (AIMS) were analysed with respect to the role of the electrocardiograph (ECG). Of these, 138 (7%) were first detected by the ECG. Of the 1256 incidents which occurred in association with general anaesthesia (GA incidents) 48% were "human detected" and 52% "monitor detected", the ECG was ranked third and detected 121 (19%) of these monitor detected GA incidents. However over 98% of incidents first detected by the ECG were heart rate changes; they would also have been detected by a pulse meter or pulse oximeter which would have supplied additional information about the adequacy of peripheral perfusion. The ECG is a "first-line" monitor in situations with the potential for myocardial ischaemia, complex dysrhythmias or altered myocardial conduction and should be used in all critically ill patients as well as those at significant risk of these problems. The ECG frequently detects incidents involving minor physiological trespass, such as simple heart rate and rhythm changes associated with anaesthetic agents. These incidents are generally detected relatively early in their evolution. AIMS data has confirmed, however, that the ECG has such poor sensitivity for serious physiological changes such as hypoxia, hypercarbia and hypotension that it cannot even be regarded as a useful "back-up" monitor for these problems. Indeed a "normal" ECG in a dangerous situation may lead to a degree of complacency.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study: an analysis of 2000 incident reports

The Australian Patient Safety Foundation was formed in 1987; it was decided to set up and co-ordinate the Australian Incident Monitoring Study as a function of this Foundation; 90 hospitals and practices joined the study. Participating anaesthetists were invited to report, on an anonymous and voluntary basis, any unintended incident which reduced, or could have reduced, the safety margin for a patient. Any incident could be reported, not only those which were deemed "preventable" or were thought to involve human error. The Mark I AIMS form was developed which incorporated features and concepts from several other studies. All the incidents in this symposium were reported using this form, which contains general instructions to the reporter, key words and space for a narrative of the incident, structured sections for what happened (with subsections for circuitry incidents, circuitry involved, equipment involved, pharmacological incidents and airway incidents), why it happened (with subsections for factors contributing to the incident, factors minimising the incident and suggested corrective strategies), the type of anaesthesia and procedure, monitors in use, when and where the incident happened, the experience of the personnel involved, patient age and a classification of patient outcome. Enrollment, reporting and data-handling procedures are described. Data on patient outcome are presented; this is correlated with the stages at which the incident occurred and with the ASA status of the patients. The locations at which the incidents occurred and the types of procedures, the sets of incidents analysed in detail and a breakdown of the incidents due to drugs are also presented.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective survey of anaesthetic critical events in a teaching hospital

A survey of anaesthetic critical events based on voluntary anonymous reports was undertaken over a two and a half year period within a teaching hospital Department of Anaesthesia. At the end of the survey 167 reports were analysed. Human error was a contributing factor in 82% of events. Inadequate preoperative patient assessment or preparation, problems in the area of human/equipment interface and various stress factors for the anaesthetist featured significantly in the survey. The method enables the collection of objective data on factors contributing to anaesthetic and surgical risk and the formulation and evaluation of potential corrective strategies. It also facilitates harmonious peer review via individual and group feedback activities. The adoption of such a survey on a wider scale is seen as a valuable part of quality assurance in the continuing attempt to increase patient safety.