Advanced life support for out-of-hospital respiratory distress

BACKGROUND

Respiratory distress is a common symptom of patients transported to hospitals by emergency medical services (EMS) personnel. The benefit of advanced life support for such patients has not been established.

METHODS

The Ontario Prehospital Advanced Life Support (OPALS) Study was a controlled clinical trial that was conducted in 15 cities before and after the implementation of a program to provide advanced life support for patients with out-of-hospital respiratory distress. Paramedics were trained in standard advanced life support, including endotracheal intubation and the administration of intravenous drugs.

RESULTS

The clinical characteristics of the 8138 patients in the two phases of the study were similar. During the first phase, no patients were treated by paramedics trained in advanced life support; during the second phase, 56.6% of patients received this treatment. Endotracheal intubation was performed in 1.4% of the patients, and intravenous drugs were administered to 15.0% during the second phase. This phase of the study was also marked by a substantial increase in the use of nebulized salbutamol and sublingual nitroglycerin for the relief of symptoms. The rate of death among all patients decreased significantly, from 14.3% to 12.4% (absolute difference, 1.9%; 95% confidence interval [CI], 0.4 to 3.4; P=0.01) from the basic-life-support phase to the advanced-life-support phase (adjusted odds ratio, 1.3; 95% CI, 1.1 to 1.5).

CONCLUSIONS

The addition of a specific regimen of out-of-hospital advanced-life-support interventions to an existing EMS system that provides basic life support was associated with a decrease in the rate of death of 1.9 percentage points among patients with respiratory distress.

Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 December 2004 with the AMANDA-II detector

On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux.

Structural evolution of the chromophore in the primary stages of trans/cis isomerization in photoactive yellow protein

We have studied the structural changes induced by optical excitation of the chromophore in wild-type photoactive yellow protein (PYP) in liquid solution with a combined approach of polarization-sensitive ultrafast infrared spectroscopy and density functional theory calculations. We identify the nuC8-C9 marker modes for solution phase PYP in the P and I0 states, from which we derive that the first intermediate state I0 that appears with a 3 ps time constant can be characterized to have a cis geometry. This is the first unequivocal demonstration that the formation of I0 correlates with the conversion from the trans to the cis state. For the P and I0 states we compare the experimentally measured vibrational band patterns and anisotropies with calculations and find that for both trans and cis configurations the planarity of the chromophore has a strong influence. The C7=C8-(C9=O)-S moiety of the chromophore in the dark P state has a trans geometry with the C=O group slightly tilted out-of-plane, in accordance with the earlier reported structure obtained in an X-ray diffraction study of PYP crystals. In the case of I0, experiment and theory are only in agreement when the C7=C8-(C9=O)-S moiety has a planar configuration. We find that the carboxylic side group of Glu46 that is hydrogen-bonded to the chromophore phenolate oxygen does not alter its orientation on going from the electronic ground P state, via the electronic excited P state to the intermediate I0 state, providing conclusive experimental evidence that the primary stages of PYP photoisomerization involve flipping of the enone thioester linkage without significant relocation of the phenolate moiety.

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.

Anharmonic couplings underlying the ultrafast vibrational dynamics of hydrogen bonds in liquids

The multilevel structure and vibrational couplings of O-H stretching transitions in intermolecular hydrogen bonds of acetic acid dimers are determined by femtosecond two-dimensional photon-echo spectroscopy in the infrared. Combining experiment and theoretical calculations, we separate Fermi resonances with combination tones of fingerprint modes from anharmonic couplings to underdamped low-frequency modes of the dimer. A multilevel density matrix approach based on density functional theory calculations reproduces the experimental results and reveals coupling strengths of both mechanisms on the order of 40-150 cm(-1).

The immediate effects of Hurricane Iniki on intertidal fauna on the south shore of O'ahu

When Hurricane Iniki struck the Hawaiian Islands in September 1992, it provided a rare opportunity to examine the immediate effects of a hurricane on two intertidal benthic communities off the reefs of O'ahu, Hawai'i. The Niu Beach site contained large, obvious aggregations of the tube building polychaete Diopatra dexiognatha, and the Wailupe Beach site was without obvious tubiculous fauna at the surface. Ten replicate sediment cores were taken before and after the hurricane with a 7.6 cm PVC corer and organisms were identified to family and enumerated. There were no substantial depletions or loss of taxa after the hurricane. Oligochaetes were the most dominant taxa pre-and post-hurricane. The abundance of all dominant polychaete families increased post-hurricane. The three most abundant polychaetes were capitellids and D. dexiognatha (Onuphidae) at Niu Beach and Pygospio muscularis (Spionidae) at Wailupe Beach. We suggest that D. dexiognatha and P. muscularis help stabilize the sediments since they both form dense tube mats while capitellids and oligochaetes are considered highly adaptive surface burrowers that can take advantage of newly disturbed sediments. Overall, there was no substantial effect observed on the intertidal fauna exposed to this severe disturbance. It is suggested here that invertebrate communities in this area are adapted to survive and thrive in high-energy environments and possibly benefit from dense aggregations of tube building polychaetes.

The Canadian C-spine rule for radiography in alert and stable trauma patients

CONTEXT

High levels of variation and inefficiency exist in current clinical practice regarding use of cervical spine (C-spine) radiography in alert and stable trauma patients.

OBJECTIVE

To derive a clinical decision rule that is highly sensitive for detecting acute C-spine injury and will allow emergency department (ED) physicians to be more selective in use of radiography in alert and stable trauma patients.

DESIGN

Prospective cohort study conducted from October 1996 to April 1999, in which physicians evaluated patients for 20 standardized clinical findings prior to radiography. In some cases, a second physician performed independent interobserver assessments.

SETTING

Ten EDs in large Canadian community and university hospitals.

PATIENTS

Convenience sample of 8924 adults (mean age, 37 years) who presented to the ED with blunt trauma to the head/neck, stable vital signs, and a Glasgow Coma Scale score of 15.

MAIN OUTCOME MEASURE

Clinically important C-spine injury, evaluated by plain radiography, computed tomography, and a structured follow-up telephone interview. The clinical decision rule was derived using the kappa coefficient, logistic regression analysis, and chi(2) recursive partitioning techniques.

RESULTS

Among the study sample, 151 (1.7%) had important C-spine injury. The resultant model and final Canadian C-Spine Rule comprises 3 main questions: (1) is there any high-risk factor present that mandates radiography (ie, age >/=65 years, dangerous mechanism, or paresthesias in extremities)? (2) is there any low-risk factor present that allows safe assessment of range of motion (ie, simple rear-end motor vehicle collision, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness)? and (3) is the patient able to actively rotate neck 45 degrees to the left and right? By cross-validation, this rule had 100% sensitivity (95% confidence interval [CI], 98%-100%) and 42.5% specificity (95% CI, 40%-44%) for identifying 151 clinically important C-spine injuries. The potential radiography ordering rate would be 58.2%.

CONCLUSION

We have derived the Canadian C-Spine Rule, a highly sensitive decision rule for use of C-spine radiography in alert and stable trauma patients. If prospectively validated in other cohorts, this rule has the potential to significantly reduce practice variation and inefficiency in ED use of C-spine radiography.

Canadian CT head rule study for patients with minor head injury: methodology for phase II (validation and economic analysis)

Prospective validation on a new set of patients is an essential test of a new decision rule. However, many clinical decision rules are not prospectively assessed to determine their accuracy, reliability, clinical sensibility, or potential impact on practice. This validation process is important because many statistically derived rules or guidelines do not perform well when tested in a new population. The methodologic standards for a validation study are similar to those described in the article on phase I for derivation studies in the August 2001 issue of Annals of Emergency Medicine. The goal of phase II is to prospectively assess the accuracy, reliability, and acceptability of the decision rule in a new set of patients with minor head injury. This will determine the clinical utility of the rule and is essential if such a rule is to be widely adopted into clinical practice.

The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation)

Head injuries are among the most common types of trauma seen in North American emergency departments, with an estimated 1 million cases seen annually. "Minor" head injury (sometimes known as "mild") is defined by a history of loss of consciousness, amnesia, or disorientation in a patient who is conscious and talking, that is, with a Glasgow Coma Scale score of 13 to 15. Although most patients with minor head injury can be discharged without sequelae after a period of observation, in a small proportion, their neurologic condition deteriorates and requires neurosurgical intervention for intracranial hematoma. The objective of the Canadian CT Head Rule Study is to develop an accurate and reliable decision rule for the use of computed tomography (CT) in patients with minor head injury. Such a decision rule would allow physicians to be more selective in their use of CT without compromising care of patients with minor head injury. This paper describes in detail the rationale, objectives, and methodology for Phase I of the study in which the decision rule was derived. [Stiell IG, Lesiuk H, Wells GA, McKnight RD, Brison R, Clement C, Eisenhauer MA, Greenberg GH, MacPhail I, Reardon M, Worthington J, Verbeek R, Rowe B, Cass D, Dreyer J, Holroyd B, Morrison L, Schull M, Laupacis A, for the Canadian CT Head and C-Spine Study Group. The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation). Ann Emerg Med. August 2001;38:160-169.]

Cocaine-induced expression of the tetraspanin CD81 and its relation to hypothalamic function

CD81, a tetraspanin transmembrane protein involved in cell adhesion, was found by differential display to be upregulated in the nucleus accumbens of rat brain following acute cocaine treatment (four injections of 30 mg/kg every 2 h followed by 24 h withdrawal). Cocaine-induced expression of CD81 in adult rat brain was confirmed by quantitative real-time RT-PCR. Its expression in neurons and its function in the brain are unknown. In situ hybridization shows a neuron-specific expression pattern in brain regions functionally related to the regulation of cardiovascular function and fluid homeostasis. CD81 displays codistribution to galanin and, to a lesser extent, to vasopressin. These findings add to data that suggest a connection between the brain reward pathway and the centers regulating endocrine and autonomic functions, in relation to neurochemical, behavioral, and somatic consequences of drug abuse.

Nuclear translocation and aggregate formation of heat shock cognate protein 70 (Hsc70) in oxidative stress and apoptosis

Recent evidence has shown a role for the heat shock cognate protein Hsc70 in the response to oxidative stress. We have investigated the subcellular distribution of Hsc70 by means of laser scanning confocal microscopy in neuroblastoma NB41A3 cells, in fibroblasts R6 cells and in R6-Bcl-2, an apoptosis-resistant cell line, and its function in oxidative stress and in apoptosis has been evaluated. Endogenous Hsc70 is localised predominantly in the cytoplasm in unstressed cells, whereas oxidative stress but not apoptosis induces its translocation into the nucleus. In transfected cells overexpressing Hsc70 increased nuclear translocation and aggregation of Hsc70 in intracellular speckles is observed after oxidative stress and, to a lesser degree, after exposure to apoptotic agents. Bcl-2 did not influence the movement of Hsc70 nor the formation of Hsc70-containing speckles. Nuclear translocation of Hsc70 can be modulated by the expression of components from a previously described plasma membrane oxidoreductase involved in the cellular response against oxidative stress. Our data may suggest a correlation between differential translocation of Hsc70 with specific functions in apoptosis and a potential role in the protection against reactive oxygen species.