Ultrafast dynamics of fluorene initiated by highly intense laser fields.

We present an investigation of the ultrafast dynamics of the polycyclic aromatic hydrocarbon fluorene initiated by an intense femtosecond near-infrared laser pulse (810 nm) and probed by a weak visible pulse (405 nm). Using a multichannel detection scheme (mass spectra, electron and ion velocity-map imaging), we provide a full disentanglement of the complex dynamics of the vibronically excited parent molecule, its excited ionic states, and fragments. We observed various channels resulting from the strong-field ionization regime. In particular, we observed the formation of the unstable tetracation of fluorene, above-threshold ionization features in the photoelectron spectra, and evidence of ubiquitous secondary fragmentation. We produced a global fit of all observed time-dependent photoelectron and photoion channels. This global fit includes four parent ions extracted from the mass spectra, 15 kinetic-energy-resolved ionic fragments extracted from ion velocity map imaging, and five photoelectron channels obtained from electron velocity map imaging. The fit allowed for the extraction of 60 lifetimes of various metastable photoinduced intermediates.

The kinetic energy of PAH dication and trication dissociation determined by recoil-frame covariance map imaging.

We investigated the dissociation of dications and trications of three polycyclic aromatic hydrocarbons (PAHs), fluorene, phenanthrene, and pyrene. PAHs are a family of molecules ubiquitous in space and involved in much of the chemistry of the interstellar medium. In our experiments, ions are formed by interaction with 30.3 nm extreme ultraviolet (XUV) photons, and their velocity map images are recorded using a PImMS2 multi-mass imaging sensor. Application of recoil-frame covariance analysis allows the total kinetic energy release (TKER) associated with multiple fragmentation channels to be determined to high precision, ranging 1.94-2.60 eV and 2.95-5.29 eV for the dications and trications, respectively. Experimental measurements are supported by Born-Oppenheimer molecular dynamics (BOMD) simulations.

Effect of Implementing the Out-of-Hospital Traumatic Brain Injury Treatment Guidelines: The Excellence in Prehospital Injury Care for Children Study (EPIC4Kids).

STUDY OBJECTIVE: We evaluate the effect of implementing the out-of-hospital pediatric traumatic brain injury guidelines on outcomes in children with major traumatic brain injury. METHODS: The Excellence in Prehospital Injury Care for Children study is the preplanned secondary analysis of the Excellence in Prehospital Injury Care study, a multisystem, intention-to-treat study using a before-after controlled design. This subanalysis included children younger than 18 years who were transported to Level I trauma centers by participating out-of-hospital agencies between January 1, 2007, and June 30, 2015, throughout Arizona. The primary and secondary outcomes were survival to hospital discharge or admission for children with major traumatic brain injury and in 3 subgroups, defined a priori as those with moderate, severe, and critical traumatic brain injury. Outcomes in the preimplementation and postimplementation cohorts were compared with logistic regression, adjusting for risk factors and confounders. RESULTS: There were 2,801 subjects, 2,041 in preimplementation and 760 in postimplementation. The primary analysis (postimplementation versus preimplementation) yielded an adjusted odds ratio of 1.16 (95% confidence interval 0.70 to 1.92) for survival to hospital discharge and 2.41 (95% confidence interval 1.17 to 5.21) for survival to hospital admission. In the severe traumatic brain injury cohort (Regional Severity Score-Head 3 or 4), but not the moderate or critical subgroups, survival to discharge significantly improved after guideline implementation (adjusted odds ratio = 8.42; 95% confidence interval 1.01 to 100+). The improvement in survival to discharge among patients with severe traumatic brain injury who received positive-pressure ventilation did not reach significance (adjusted odds ratio = 9.13; 95% confidence interval 0.79 to 100+). CONCLUSION: Implementation of the pediatric out-of-hospital traumatic brain injury guidelines was not associated with improved survival when the entire spectrum of severity was analyzed as a whole (moderate, severe, and critical). However, both adjusted survival to hospital admission and discharge improved in children with severe traumatic brain injury, indicating a potential severity-based interventional opportunity for guideline effectiveness. These findings support the widespread implementation of the out-of-hospital pediatric traumatic brain injury guidelines.

X-ray diffractive imaging of controlled gas-phase molecules: Toward imaging of dynamics in the molecular frame.

We report experimental results on the diffractive imaging of three-dimensionally aligned 2,5-diiodothiophene molecules. The molecules were aligned by chirped near-infrared laser pulses, and their structure was probed at a photon energy of 9.5 keV (λ ≈ 130 pm) provided by the Linac Coherent Light Source. Diffracted photons were recorded on the Cornell-SLAC pixel array detector, and a two-dimensional diffraction pattern of the equilibrium structure of 2,5-diiodothiophene was recorded. The retrieved distance between the two iodine atoms agrees with the quantum-chemically calculated molecular structure to be within 5%. The experimental approach allows for the imaging of intrinsic molecular dynamics in the molecular frame, albeit this requires more experimental data, which should be readily available at upcoming high-repetition-rate facilities.

Atomic-resolution imaging of carbonyl sulfide by laser-induced electron diffraction.

Measurements on the strong-field ionization of carbonyl sulfide molecules by short, intense, 2 µm wavelength laser pulses are presented from experiments where angle-resolved photoelectron distributions were recorded with a high-energy velocity map imaging spectrometer, designed to reach a maximum kinetic energy of 500 eV. The laser-field-free elastic-scattering cross section of carbonyl sulfide was extracted from the measurements and is found in good agreement with previous experiments, performed using conventional electron diffraction. By comparing our measurements to the results of calculations, based on the quantitative rescattering theory, the bond lengths and molecular geometry were extracted from the experimental differential cross sections to a precision better than ±5 pm and in agreement with the known values.

Communication: Strong laser alignment of solvent-solute aggregates in the gas-phase.

Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of the electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with ⟨cos2 θ2D⟩ ≥ 0.9.

Communication: Switched wave packets with spectrally truncated chirped pulses.

A new technique for obtaining switched wave packets using spectrally truncated chirped laser pulses is demonstrated experimentally and numerically by one-dimensional alignment of both linear and asymmetric top molecules. Using a simple long-pass transmission filter, a pulse with a slow turn-on and a rapid turn-off is produced. The degree of alignment, characterized by ⟨cos2 θ2D⟩, rises along with the pulse intensity and reaches a maximum at the peak of the pulse. After truncation, ⟨cos2 θ2D⟩ drops sharply but exhibits pronounced half and full revivals. The experimental alignment dynamics trace agrees very well with a numerically calculated trace based on the solution of the time-dependent Schrödinger equation. However, the extended periods of field-free alignment of asymmetric tops following pulse truncation reported previously are not reproduced in our work.

The Effect of Combined Out-of-Hospital Hypotension and Hypoxia on Mortality in Major Traumatic Brain Injury.

STUDY OBJECTIVE: Survival is significantly reduced by either hypotension or hypoxia during the out-of-hospital management of major traumatic brain injury. However, only a handful of small studies have investigated the influence of the combination of both hypotension and hypoxia occurring together. In patients with major traumatic brain injury, we evaluate the associations between mortality and out-of-hospital hypotension and hypoxia separately and in combination. METHODS: All moderate or severe traumatic brain injury cases in the preimplementation cohort of the Excellence in Prehospital Injury Care study (a statewide, before/after, controlled study of the effect of implementing the out-of-hospital traumatic brain injury treatment guidelines) from January 1, 2007, to March 31, 2014, were evaluated (exclusions: <10 years, out-of-hospital oxygen saturation ≤10%, and out-of-hospital systolic blood pressure <40 or >200 mm Hg). The relationship between mortality and hypotension (systolic blood pressure <90 mm Hg) or hypoxia (saturation <90%) was assessed with multivariable logistic regression, controlling for Injury Severity Score, head region severity, injury type (blunt versus penetrating), age, sex, race, ethnicity, payer, interhospital transfer, and trauma center. RESULTS: Among the 13,151 patients who met inclusion criteria (median age 45 years; 68.6% men), 11,545 (87.8%) had neither hypotension nor hypoxia, 604 (4.6%) had hypotension only, 790 (6.0%) had hypoxia only, and 212 (1.6%) had both hypotension and hypoxia. Mortality for the 4 study cohorts was 5.6%, 20.7%, 28.1%, and 43.9%, respectively. The crude and adjusted odds ratios for death within the cohorts, using the patients with neither hypotension nor hypoxia as the reference, were 4.4 and 2.5, 6.6 and 3.0, and 13.2 and 6.1, respectively. Evaluation for an interaction between hypotension and hypoxia revealed that the effects were additive on the log odds of death. CONCLUSION: In this statewide analysis of major traumatic brain injury, combined out-of-hospital hypotension and hypoxia were associated with significantly increased mortality. This effect on survival persisted even after controlling for multiple potential confounders. In fact, the adjusted odds of death for patients with both hypotension and hypoxia were more than 2 times greater than for those with either hypotension or hypoxia alone. These findings seem supportive of the emphasis on aggressive prevention and treatment of hypotension and hypoxia reflected in the current emergency medical services traumatic brain injury treatment guidelines but clearly reveal the need for further study to determine their influence on outcome.

Association of Out-of-Hospital Hypotension Depth and Duration With Traumatic Brain Injury Mortality.

STUDY OBJECTIVE: Out-of-hospital hypotension has been associated with increased mortality in traumatic brain injury. The association of traumatic brain injury mortality with the depth or duration of out-of-hospital hypotension is unknown. We evaluated the relationship between the depth and duration of out-of-hospital hypotension and mortality in major traumatic brain injury. METHODS: We evaluated adults and older children with moderate or severe traumatic brain injury in the preimplementation cohort of Arizona's statewide Excellence in Prehospital Injury Care study. We used logistic regression to determine the association between the depth-duration dose of hypotension (depth of systolic blood pressure <90 mm Hg integrated over duration [minutes] of hypotension) and odds of inhospital death, controlling for significant confounders. RESULTS: There were 7,521 traumatic brain injury cases included (70.6% male patients; median age 40 years [interquartile range 24 to 58]). Mortality was 7.8% (95% confidence interval [CI] 7.2% to 8.5%) among the 6,982 patients without hypotension (systolic blood pressure ≥90 mm Hg) and 33.4% (95% CI 29.4% to 37.6%) among the 539 hypotensive patients (systolic blood pressure <90 mm Hg). Mortality was higher with increased hypotension dose: 0.01 to 14.99 mm Hg-minutes 16.3%; 15 to 49.99 mm Hg-minutes 28.1%; 50 to 141.99 mm Hg-minutes 38.8%; and greater than or equal to 142 mm Hg-minutes 50.4%. Log2 (the logarithm in base 2) of hypotension dose was associated with traumatic brain injury mortality (adjusted odds ratio 1.19 [95% CI 1.14 to 1.25] per 2-fold increase of dose). CONCLUSION: In this study, the depth and duration of out-of-hospital hypotension were associated with increased traumatic brain injury mortality. Assessments linking out-of-hospital blood pressure with traumatic brain injury outcomes should consider both depth and duration of hypotension.

Body Temperature after EMS Transport: Association with Traumatic Brain Injury Outcomes.

INTRODUCTION: Low body temperatures following prehospital transport are associated with poor outcomes in patients with traumatic brain injury (TBI). However, a minimal amount is known about potential associations across a range of temperatures obtained immediately after prehospital transport. Furthermore, a minimal amount is known about the influence of body temperature on non-mortality outcomes. The purpose of this study was to assess the correlation between temperatures obtained immediately following prehospital transport and TBI outcomes across the entire range of temperatures. METHODS: This retrospective observational study included all moderate/severe TBI cases (CDC Barell Matrix Type 1) in the pre-implementation cohort of the Excellence in Prehospital Injury Care (EPIC) TBI Study (NIH/NINDS: 1R01NS071049). Cases were compared across four cohorts of initial trauma center temperature (ITCT): <35.0°C [Very Low Temperature (VLT)]; 35.0-35.9°C [Low Temperature (LT)]; 36.0-37.9°C [Normal Temperature (NT)]; and ≥38.0°C [Elevated Temperature (ET)]. Multivariable analysis was performed adjusting for injury severity score, age, sex, race, ethnicity, blunt/penetrating trauma, and payment source. Adjusted odds ratios (aORs) with 95% confidence intervals (CI) for mortality were calculated. To evaluate non-mortality outcomes, deaths were excluded and the adjusted median increase in hospital length of stay (LOS), ICU LOS and total hospital charges were calculated for each ITCT group and compared to the NT group. RESULTS: 22,925 cases were identified and cases with interfacility transfer (7361, 32%), no EMS transport (1213, 5%), missing ITCT (2083, 9%), or missing demographic data (391, 2%) were excluded. Within this study cohort the aORs for death (compared to the NT group) were 2.41 (CI: 1.83-3.17) for VLT, 1.62 (CI: 1.37-1.93) for LT, and 1.86 (CI: 1.52-3.00) for ET. Similarly, trauma center (TC) LOS, ICU LOS, and total TC charges increased in all temperature groups when compared to NT. CONCLUSION: In this large, statewide study of major TBI, both ETs and LTs immediately following prehospital transport were independently associated with higher mortality and with increased TC LOS, ICU LOS, and total TC charges. Further study is needed to identify the causes of abnormal body temperature during the prehospital interval and if in-field measures to prevent temperature variations might improve outcomes.

Adiabatic Mixed-Field Orientation of Ground-State-Selected Carbonyl Sulfide Molecules.

A strong adiabatic mixed-field orientation (Nup /Ntot =0.882) of carbonyl sulfide (OCS) molecules in their absolute ground state is experimentally demonstrated. OCS is oriented in a combination of nonresonant laser and static electric fields inside a two-plate velocity map imaging spectrometer. The transition from nonadiabatic to adiabatic orientation for the rotational ground state is studied by varying the applied laser intensity and static electric field. Above static electric field strengths of 10 kV cm-1 and laser intensities of 1011 W cm-2 the observed degree of orientation reaches a plateau. These results are in good agreement with computational solutions of the time-dependent Schrödinger equation.

Two-state wave packet for strong field-free molecular orientation.

We demonstrate strong laser-field-free orientation of absolute-ground-state carbonyl sulfide molecules. The molecules are oriented by the combination of a 485-ps-long nonresonant laser pulse and a weak static electric field. The edges of the laser pulse create a coherent superposition of two rotational states resulting in revivals of strong transient molecular orientation after the laser pulse. The experimentally attained degree of orientation ⟨cosθ⟩≈0.6 corresponds to the theoretical maximum for mixing of the two states. Switching off the dc field would provide the same orientation completely field free.

Statewide regionalization of postarrest care for out-of-hospital cardiac arrest: association with survival and neurologic outcome.

STUDY OBJECTIVE: For out-of-hospital cardiac arrest, authoritative, evidence-based recommendations have been made for regionalization of postarrest care. However, system-wide implementation of these guidelines has not been evaluated. Our hypothesis is that statewide regionalization of postarrest interventions, combined with emergency medical services (EMS) triage bypass, is associated with improved survival and neurologic outcome. METHODS: This was a prospective before-after observational study comparing patients admitted to cardiac receiving centers before implementation of the interventions ("before") versus those admitted after ("after"). In December 2007, the Arizona Department of Health Services began officially recognizing cardiac receiving centers according to commitment to provide specified postarrest care. Subsequently, the State EMS Council approved protocols allowing preferential EMS transport to these centers. Participants were adults (≥ 18 years) experiencing out-of-hospital cardiac arrest of presumed cardiac cause who were transported to a cardiac receiving center. Interventions included (1) implementation of postarrest care at cardiac receiving centers focusing on provision of therapeutic hypothermia and coronary angiography or percutaneous coronary interventions (catheterization/PCI); and (2) implementation of EMS bypass triage protocols. Main outcomes included discharged alive from the hospital and cerebral performance category score at discharge. RESULTS: During the study (December 1, 2007, to December 31, 2010), 31 hospitals were recognized as cardiac receiving centers statewide. Four hundred forty patients were transported to cardiac receiving centers before and 1,737 after. Provision of therapeutic hypothermia among patients with return of spontaneous circulation increased from 0% (before: 0/145; 95% confidence interval [CI] 0% to 2.5%) to 44.0% (after: 300/682; 95% CI 40.2, 47.8). The post return of spontaneous circulation catheterization PCI rate increased from 11.7% (17/145; 95% CI 7.0, 18.1) before to 30.7% (210/684; 95% CI 27.3, 34.3) after. All-rhythm survival increased from 8.9% (39/440) to 14.4% (250/1,734; adjusted odds ratio [aOR] = 2.22; 95% CI 1.47 to 3.34). Survival with favorable neurologic outcome (cerebral performance category score = 1 or 2) increased from 5.9% (26/439) to 8.9% (153/1,727; aOR = 2.26 [95% CI 1.37, 3.73]). For witnessed shockable rhythms, survival increased from 21.4% (21/98) to 39.2% (115/293; aOR = 2.96 [95% CI 1.63, 5.38]) and cerebral performance category score = 1 or 2 increased from 19.4% (19/98) to 29.8% (87/292; aOR = 2.12 [95% CI 1.14, 3.93]). CONCLUSION: Implementation of a statewide system of cardiac receiving centers and EMS bypass was independently associated with increased overall survival and favorable neurologic outcome. In addition, these outcomes improved among patients with witnessed shockable rhythms.

Picosecond pulse-shaping for strong three-dimensional field-free alignment of generic asymmetric-top molecules.

Fixing molecules in space is a crucial step for the imaging of molecular structure and dynamics. Here, we demonstrate three-dimensional (3D) field-free alignment of the prototypical asymmetric top molecule indole using elliptically polarized, shaped, off-resonant laser pulses. A truncated laser pulse is produced using a combination of extreme linear chirping and controlled phase and amplitude shaping using a spatial-light-modulator (SLM) based pulse shaper of a broadband laser pulse. The angular confinement is detected through velocity-map imaging of H+ and C2+ fragments resulting from strong-field ionization and Coulomb explosion of the aligned molecules by intense femtosecond laser pulses. The achieved three-dimensional alignment is characterized by comparing the result of ion-velocity-map measurements for different alignment directions and for different times during and after the alignment laser pulse to accurate computational results. The achieved strong three-dimensional field-free alignment of [Formula: see text] demonstrates the feasibility of both, strong three-dimensional alignment of generic complex molecules and its quantitative characterization.

Chest compression-only CPR by lay rescuers and survival from out-of-hospital cardiac arrest.

CONTEXT: Chest compression-only bystander cardiopulmonary resuscitation (CPR) may be as effective as conventional CPR with rescue breathing for out-of-hospital cardiac arrest. OBJECTIVE: To investigate the survival of patients with out-of-hospital cardiac arrest using compression-only CPR (COCPR) compared with conventional CPR. DESIGN, SETTING, AND PATIENTS: A 5-year prospective observational cohort study of survival in patients at least 18 years old with out-of-hospital cardiac arrest between January 1, 2005, and December 31, 2009, in Arizona. The relationship between layperson bystander CPR and survival to hospital discharge was evaluated using multivariable logistic regression. MAIN OUTCOME MEASURE: Survival to hospital discharge. RESULTS: Among 5272 adults with out-of-hospital cardiac arrest of cardiac etiology not observed by responding emergency medical personnel, 779 were excluded because bystander CPR was provided by a health care professional or the arrest occurred in a medical facility. A total of 4415 met all inclusion criteria for analysis, including 2900 who received no bystander CPR, 666 who received conventional CPR, and 849 who received COCPR. Rates of survival to hospital discharge were 5.2% (95% confidence interval [CI], 4.4%-6.0%) for the no bystander CPR group, 7.8% (95% CI, 5.8%-9.8%) for conventional CPR, and 13.3% (95% CI, 11.0%-15.6%) for COCPR. The adjusted odds ratio (AOR) for survival for conventional CPR vs no CPR was 0.99 (95% CI, 0.69-1.43), for COCPR vs no CPR, 1.59 (95% CI, 1.18-2.13), and for COCPR vs conventional CPR, 1.60 (95% CI, 1.08-2.35). From 2005 to 2009, lay rescuer CPR increased from 28.2% (95% CI, 24.6%-31.8%) to 39.9% (95% CI, 36.8%-42.9%; P < .001); the proportion of CPR that was COCPR increased from 19.6% (95% CI, 13.6%-25.7%) to 75.9% (95% CI, 71.7%-80.1%; P < .001). Overall survival increased from 3.7% (95% CI, 2.2%-5.2%) to 9.8% (95% CI, 8.0%-11.6%; P < .001). CONCLUSION: Among patients with out-of-hospital cardiac arrest, layperson compression-only CPR was associated with increased survival compared with conventional CPR and no bystander CPR in this setting with public endorsement of chest compression-only CPR.

Setting the photoelectron clock through molecular alignment.

The interaction of strong laser fields with matter intrinsically provides a powerful tool for imaging transient dynamics with an extremely high spatiotemporal resolution. Here, we study strong-field ionisation of laser-aligned molecules, and show a full real-time picture of the photoelectron dynamics in the combined action of the laser field and the molecular interaction. We demonstrate that the molecule has a dramatic impact on the overall strong-field dynamics: it sets the clock for the emission of electrons with a given rescattering kinetic energy. This result represents a benchmark for the seminal statements of molecular-frame strong-field physics and has strong impact on the interpretation of self-diffraction experiments. Furthermore, the resulting encoding of the time-energy relation in molecular-frame photoelectron momentum distributions shows the way of probing the molecular potential in real-time, and accessing a deeper understanding of electron transport during strong-field interactions.

Molecular movie of ultrafast coherent rotational dynamics of OCS.

Recording molecular movies on ultrafast timescales has been a longstanding goal for unravelling detailed information about molecular dynamics. Here we present the direct experimental recording of very-high-resolution and -fidelity molecular movies over more than one-and-a-half periods of the laser-induced rotational dynamics of carbonylsulfide (OCS) molecules. Utilising the combination of single quantum-state selection and an optimised two-pulse sequence to create a tailored rotational wavepacket, an unprecedented degree of field-free alignment, 〈cos2θ2D〉 = 0.96 (〈cos2θ〉 = 0.94) is achieved, exceeding the theoretical limit for single-pulse alignment. The very rich experimentally observed quantum dynamics is fully recovered by the angular probability distribution obtained from solutions of the time-dependent Schrödinger equation with parameters refined against the experiment. The populations and phases of rotational states in the retrieved time-dependent three-dimensional wavepacket rationalises the observed very high degree of alignment.

Association of Statewide Implementation of the Prehospital Traumatic Brain Injury Treatment Guidelines With Patient Survival Following Traumatic Brain Injury: The Excellence in Prehospital Injury Care (EPIC) Study.

Importance: Traumatic brain injury (TBI) is a massive public health problem. While evidence-based guidelines directing the prehospital treatment of TBI have been promulgated, to our knowledge, no studies have assessed their association with survival. Objective: To evaluate the association of implementing the nationally vetted, evidence-based, prehospital treatment guidelines with outcomes in moderate, severe, and critical TBI. Design, Setting, and Participants: The Excellence in Prehospital Injury Care (EPIC) Study included more than 130 emergency medical services systems/agencies throughout Arizona. This was a statewide, multisystem, intention-to-treat study using a before/after controlled design with patients with moderate to critically severe TBI (US Centers for Disease Control and Prevention Barell Matrix-Type 1 and/or Abbreviated Injury Scale Head region severity ≥3) transported to trauma centers between January 1, 2007, and June 30, 2015. Data were analyzed between October 25, 2017, and February 22, 2019. Interventions: Implementation of the prehospital TBI guidelines emphasizing avoidance/treatment of hypoxia, prevention/correction of hyperventilation, and avoidance/treatment of hypotension. Main Outcomes and Measures: Primary: survival to hospital discharge; secondary: survival to hospital admission. Results: Of the included patients, the median age was 45 years, 14 666 (67.1%) were men, 7181 (32.9%) were women; 16 408 (75.1% ) were white, 1400 (6.4%) were Native American, 743 (3.4% ) were Black, 237 (1.1%) were Asian, and 2791 (12.8%) were other race/ethnicity. Of the included patients, 21 852 met inclusion criteria for analysis (preimplementation phase [P1]: 15 228; postimplementation [P3]: 6624). The primary analysis (P3 vs P1) revealed an adjusted odds ratio (aOR) of 1.06 (95% CI, 0.93-1.21; P = .40) for survival to hospital discharge. The aOR was 1.70 (95% CI, 1.38-2.09; P < .001) for survival to hospital admission. Among the severe injury cohorts (but not moderate or critical), guideline implementation was significantly associated with survival to discharge (Regional Severity Score-Head 3-4: aOR, 2.03; 95% CI, 1.52-2.72; P < .001; Injury Severity Score 16-24: aOR, 1.61; 95% CI, 1.07-2.48; P = .02). This was also true for survival to discharge among the severe, intubated subgroups (Regional Severity Score-Head 3-4: aOR, 3.14; 95% CI, 1.65-5.98; P < .001; Injury Severity Score 16-24: aOR, 3.28; 95% CI, 1.19-11.34; P = .02). Conclusions and Relevance: Statewide implementation of the prehospital TBI guidelines was not associated with significant improvement in overall survival to hospital discharge (across the entire, combined moderate to critical injury spectrum). However, adjusted survival doubled among patients with severe TBI and tripled in the severe, intubated cohort. Furthermore, guideline implementation was significantly associated with survival to hospital admission. These findings support the widespread implementation of the prehospital TBI treatment guidelines. Trial Registration: ClinicalTrials.gov identifier: NCT01339702.

The impact of prehospital transport interval on survival in out-of-hospital cardiac arrest: implications for regionalization of post-resuscitation care.

OBJECTIVE: There is growing evidence that therapeutic hypothermia and other post-resuscitation care improves outcomes in out-of-hospital cardiac arrest (OHCA). Thus, transporting patients with return of spontaneous circulation (ROSC) to specialized facilities may increase survival rates. However, it is unknown whether prolonging transport to reach a designated facility would be detrimental. METHODS: Data from OHCA patients treated in EMS systems that cover approximately 70% of Arizona's population were evaluated (October 2004-December 2006). We analyzed the association between transport interval (depart scene to ED arrival) and survival to hospital discharge in adult, non-traumatic OHCA patients and in the subgroup who achieved ROSC and remained comatose. RESULTS: 1846 OHCA occurred prior to EMS arrival. Complete transport interval data were available for 1177 (63.8%) patients (study group). 253 patients (21.5%) achieved ROSC and remained comatose making them theoretically eligible for transport to specialized care. Overall, 70 patients (5.9%) survived and 43 (17.0%) comatose ROSC patients survived. Mean transport interval for the study group was 6.9 min (95% CI: 6.7, 7.1). Logistic regression revealed factors that were independently associated with survival: witnessed arrest, bystander CPR, method of CPR, initial rhythm of ventricular fibrillation, and shorter EMS response time interval. There was no significant association between transport interval and outcome in either the overall study group (OR=1.2; 0.77, 1.8) or in the comatose, ROSC subgroup (OR 0.94; 0.51, 1.8). CONCLUSION: Survival was not significantly impacted by transport interval. This suggests that a modest increase in transport interval from bypassing the closest hospital en route to specialized care is safe and warrants further investigation.

Note: Knife edge skimming for improved separation of molecular species by the deflector.

A knife edge for shaping a molecular beam is described to improve the spatial separation of the species in a molecular beam by the electrostatic deflector. The spatial separation of different molecular species from each other as well as from atomic seed gas is improved. The column density of the selected molecular-beam part in the interaction zone, which corresponds to higher signal rates, was enhanced by a factor of 1.5, limited by the virtual source size of the molecular beam.