Out with the old, in with the new: how changes in cricket helmet regulations affect the vision of batters.

The International Cricket Council recently introduced new regulations for helmets in cricket. Amongst other changes, these regulations limit batters from adjusting the gap between the peak and the grille, resulting in some controversy over whether the new helmet design reduces visibility of the ball. This study compared the visual field of individuals when wearing an old helmet that does not conform to the new regulations, and the equivalent replacement which does. The visual field of 10 male participants was tested whilst wearing an old and new helmet. The new helmet resulted in a significant reduction in the visual field of the wearer (M = 66.1 out of 76 points seen in the new helmet vs. 74.8 seen with the old helmet), with the restriction predominantly confined to the superior visual field. The new regulations do appear to restrict the visual field of batters, confirming the anecdotal reports of players. However, the majority of this restriction occurs in the superior field, suggesting that the impact on batting performance may be limited. The importance of considering the impact that new helmet regulations can have on vision, batting performance, and player safety is discussed.

Information-theoretic analysis of iterated Bayesian acoustic source localization in a static ocean waveguide.

Fundamental constructs of information theory are applied to quantify the performance of iterated (sequential) Bayesian localization of a time-harmonic source in a range- and time-invariant acoustic waveguide using the segmented Fourier transforms of the received pressure time series. The nonlinear relation, defined by acoustic propagation, between the source location and the received narrowband spectral components is treated as a nonlinear communication channel. The performance analysis includes mismatch between the acoustic channel and the model channel on which the Bayesian inference is based. Source location uncertainty is quantified by the posterior probability density of source location, by the posterior entropy and associated uncertainty area, by the information gain (relative entropy) at each iteration, and by large-ensemble limits of these quantities. A computational example for a vertical receiver array in a shallow-water waveguide is presented with acoustic propagation represented by normal modes and ambient noise represented by a Kuperman-Ingenito model. Performance degradation due to noise-model mismatch is quantified in an example. Potential extensions to uncertain and stochastic environments are discussed.

Stop the Bleed-Wait for the Ambulance or Get in the Car and Drive? A Post Hoc Analysis of an EAST Multicenter Trial.

Background: The Stop the Bleed campaign gives bystanders an active role in prehospital hemorrhage control. Whether extending bystanders' role to private vehicle transport (PVT) for urban penetrating trauma improves survival is unknown, but past research has found benefit to police and PVT. We hypothesized that for penetrating trauma in an urban environment, where prehospital procedures have been proven harmful, PVT improves outcomes compared to any EMS or advanced life support (ALS) transport.Methods: Post-hoc analysis of an EAST multicenter trial was performed on adult patients with penetrating torso/proximal extremity trauma at 25 urban trauma centers from 5/2019-5/2020. Patients were allocated to PVT and any EMS or ALS transport using nearest neighbor propensity score matching. Univariate analyses included Wilcoxon signed rank or McNemar's Test and logistic regression.Results: Of 1999 penetrating trauma patients in urban settings, 397 (19.9%) had PVT, 1433 (71.7%) ALS transport, and 169 (8.5%) basic life support (BLS) transport. Propensity matching yielded 778 patients, distributed equally into balanced groups. PVT patients were primarily male (90.5%), Black (71.2%), and sustained gunshot wounds (68.9%). ALS transport had significantly higher ED mortality (3.9% vs 1.9%, P = 0.03). There was no difference in in-hospital mortality rate, hospital LOS, or complications for all EMS or ALS only transport patients.Conclusion: Compared to PVT, ALS, which provides more prehospital procedures than BLS, provided no survival benefit for penetrating trauma patients in urban settings. Bystander education incorporating PVT for early arrival of penetrating trauma patients in urban settings to definitive care merits further investigation.

Tranexamic Acid and Pulmonary Complications: A Secondary Analysis of an EAST Multicenter Trial.

BACKGROUND: Anti-inflammatory effects of tranexamic acid (TXA) in reducing trauma endotheliopathy may protect from acute lung injury. Clinical data showing this benefit in trauma patients is lacking. We hypothesized that TXA administration mitigates pulmonary complications in penetrating trauma patients. MATERIALS AND METHODS: This is a post-hoc analysis of a multicenter, prospective, observational study of adults (18+ years) with penetrating torso and/or proximal extremity injury presenting at 25 urban trauma centers. Tranexamic acid administration in the prehospital setting or within three hours of admission was examined. Participants were propensity matched to compare similarly injured patients. The primary outcome was development of pulmonary complication (ARDS and/or pneumonia). RESULTS: A total of 2382 patients were included, and 206 (8.6%) received TXA. Of the 206, 93 (45%) received TXA prehospital and 113 (55%) received it within three hours of hospital admission. Age, sex, and incidence of massive transfusion did not differ. The TXA group was more severely injured, more frequently presented in shock (SBP < 90 mmHg), developed more pulmonary complications, and had lower survival (P < 0.01 for all). After propensity matching, 410 patients remained (205 in each cohort) with no difference in age, sex, or rate of shock. On logistic regression, increased emergency department heart rate was associated with pulmonary complications. Tranexamic acid was not associated with different rate of pulmonary complications or survival on logistic regression. Survival was not different between the groups on logistic regression or propensity score-matched analysis. CONCLUSIONS: Tranexamic acid administration is not protective against pulmonary complications in penetrating trauma patients.

Empirical and quadrature approximation of acoustic field and array response probability density functions.

Numerical methods are presented for approximating the probability density functions (pdf's) of acoustic fields and receiver-array responses induced by a given joint pdf of a set of acoustic environmental parameters. An approximation to the characteristic function of the random acoustic field (the inverse Fourier transform of the field pdf) is first obtained either by construction of the empirical characteristic function (ECF) from a random sample of the acoustic parameters, or by application of generalized Gaussian quadrature to approximate the integral defining the characteristic function. The Fourier transform is then applied to obtain an approximation of the pdf by a continuous function of the field variables. Application of both the ECF and generalized Gaussian quadrature is demonstrated in an example of a shallow-water ocean waveguide with two-dimensional uncertainty of sound speed and attenuation coefficient in the ocean bottom. Both approximations lead to a smoother estimate of the field pdf than that provided by a histogram, with generalized Gaussian quadrature providing a smoother estimate at the tails of the pdf. Potential applications to acoustic system performance quantification and to nonparametric acoustic signal processing are discussed.

Realization of the manipulation of ultracold atoms with a reconfigurable nanomagnetic system of domain walls.

Planar magnetic nanowires have been vital to the development of spintronic technology. They provide an unparalleled combination of magnetic reconfigurability, controllability, and scalability, which has helped to realize such applications as racetrack memory and novel logic gates. Microfabricated atom optics benefit from all of these properties, and we present the first demonstration of the amalgamation of spintronic technology with ultracold atoms. A magnetic interaction is exhibited through the reflection of a cloud of (87)Rb atoms at a temperature of 10 µK, from a 2 mm × 2 mm array of nanomagnetic domain walls. In turn, the incident atoms approach the array at heights of the order of 100 nm and are thus used to probe magnetic fields at this distance.

Acoustic field and array response uncertainties in stratified ocean media.

The change-of-variables theorem of probability theory is applied to compute acoustic field and array beam power probability density functions (pdfs) in uncertain ocean environments represented by stratified, attenuating ocean waveguide models. Computational studies for one and two-layer waveguides investigate the functional properties of the acoustic field and array beam power pdfs. For the studies, the acoustic parameter uncertainties are represented by parametric pdfs. The field and beam response pdfs are computed directly from the parameter pdfs using the normal-mode representation and the change-of-variables theorem. For two-dimensional acoustic parameter uncertainties of sound speed and attenuation, the field and beam power pdfs exhibit irregular functional behavior and singularities associated with stationary points of the mapping, defined by acoustic propagation, from the parameter space to the field or beam power space. Implications for the assessment of orthogonal polynomial expansion and other methods for computing acoustic field pdfs are discussed.

Eastern Association for the Surgery of Trauma Multicenter Trial: Comparison of pre-injury antithrombotic use and reversal strategies among severe traumatic brain injury patients.

BACKGROUND: Trauma teams are often faced with patients on antithrombotic (AT) drugs, which is challenging when bleeding occurs. We sought to compare the effects of different AT medications on head injury severity and hypothesized that AT reversal would not improve mortality in severe traumatic brain injury (TBI) patients. METHODS: An Eastern Association for the Surgery of Trauma-sponsored prospective, multicentered, observational study of 15 trauma centers was performed. Patient demographics, injury burden, comorbidities, AT agents, and reversal attempts were collected. Outcomes of interest were head injury severity and in-hospital mortality. RESULTS: Analysis was performed on 2,793 patients. The majority of patients were on aspirin (acetylsalicylic acid [ASA], 46.1%). Patients on a platelet chemoreceptor blocker (P2Y12) had the highest mean Injury Severity Score (9.1 ± 8.1). Patients taking P2Y12 inhibitors ± ASA, and ASA-warfarin had the highest head Abbreviated Injury Scale (AIS) mean (1.2 ± 1.6). On risk-adjusted analysis, warfarin-ASA was associated with a higher head AIS (odds ratio [OR], 2.43; 95% confidence interval [CI], 1.34-4.42) after controlling for Injury Severity Score, Charlson Comorbidity Index, initial Glasgow Coma Scale score, and initial systolic blood pressure. Among patients with severe TBI (head AIS score, ≥3) on antiplatelet therapy, reversal with desmopressin (DDAVP) and/or platelet transfusion did not improve survival (82.9% reversal vs. 90.4% none, p = 0.30). In severe TBI patients taking Xa inhibitors who received prothrombin complex concentrate, survival was not improved (84.6% reversal vs. 84.6% none, p = 0.68). With risk adjustment as described previously, mortality was not improved with reversal attempts (antiplatelet agents: OR 0.83; 85% CI, 0.12-5.9 [p = 0.85]; Xa inhibitors: OR, 0.76; 95% CI, 0.12-4.64; p = 0.77). CONCLUSION: Reversal attempts appear to confer no mortality benefit in severe TBI patients on antiplatelet agents or Xa inhibitors. Combination therapy was associated with severity of head injury among patients taking preinjury AT therapy, with ASA-warfarin possessing the greatest risk. LEVEL OF EVIDENCE: Prognostic, level II.

An analysis of police transport in an Eastern Association for the Surgery of Trauma multicenter trial examining prehospital procedures in penetrating trauma patients.

BACKGROUND: Police transport (PT) of penetrating trauma patients in urban locations has become routine in certain metropolitan areas; however, whether it results in improved outcomes over prehospital Advanced life support (ALS) transport has not been determined in a multicenter study. We hypothesized that PT would not result in improved outcomes. METHODS: This was a multicenter, prospective, observational study of adults (18+ years) with penetrating trauma to the torso and/or proximal extremity presenting at 25 urban trauma centers. Police transport and ALS patients were allocated via nearest neighbor, propensity matching. Transport mode also examined by Cox regression. RESULTS: Of 1,618 total patients, 294 (18.2%) had PT and 1,324 (81.8%) were by ALS. After matching, 588 (294/cohort) remained. The patients were primarily Black (n = 497, 84.5%), males (n = 525, 89.3%, injured by gunshot wound (n = 494, 84.0%) with 34.5% (n = 203) having Injury Severity Score of 16 or higher. Overall mortality by propensity matching was not different between cohorts (15.6% ALS vs. 15.0% PT, p = 0.82). In severely injured patients (Injury Severity Score ≥16), mortality did not differ between PT and ALS transport (38.8% vs. 36.0%, respectively; p = 0.68). Cox regression analysis controlled for relevant factors revealed no association with a mortality benefit in patients transported by ALS. CONCLUSION: Police transport of penetrating trauma patients in urban locations results in similar outcomes compared with ALS. Immediate transport to definitive trauma care should be emphasized in this patient population. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

Mid-infrared images of beta Pictoris and the possible role of planetesimal collisions in the central disk.

When viewed in optical starlight scattered by dust, the nearly edge-on debris disk surrounding the A5V star beta Pictoris (distance 19.3 pc; ref. 1) extends farther than 1,450 au from the star. Its large-scale complexity has been well characterized, but the detailed structure of the disk's central approximately 200-au region has remained elusive. This region is of special interest, because planets may have formed there during the star's 10-20-million-year lifetime, perhaps resulting in both the observed tilt of 4.6 degrees relative to the large-scale main disk and the partial clearing of the innermost dust. A peculiarity of the central disk (also possibly related to the presence of planets) is the asymmetry in the brightness of the 'wings', in which the southwestern wing is brighter and more extended at 12 microm than the northeastern wing. Here we present thermal infrared images of the central disk that imply that the brightness asymmetry results from the presence of a bright clump composed of particles that may differ in size from dust elsewhere in the disk. We suggest that this clump results from the collisional grinding of resonantly trapped planetesimals or the cataclysmic break-up of a planetesimal.

Neuromorphic computation with a single magnetic domain wall.

Machine learning techniques are commonly used to model complex relationships but implementations on digital hardware are relatively inefficient due to poor matching between conventional computer architectures and the structures of the algorithms they are required to simulate. Neuromorphic devices, and in particular reservoir computing architectures, utilize the inherent properties of physical systems to implement machine learning algorithms and so have the potential to be much more efficient. In this work, we demonstrate that the dynamics of individual domain walls in magnetic nanowires are suitable for implementing the reservoir computing paradigm in hardware. We modelled the dynamics of a domain wall placed between two anti-notches in a nickel nanowire using both a 1D collective coordinates model and micromagnetic simulations. When driven by an oscillating magnetic field, the domain exhibits non-linear dynamics within the potential well created by the anti-notches that are analogous to those of the Duffing oscillator. We exploit the domain wall dynamics for reservoir computing by modulating the amplitude of the applied magnetic field to inject time-multiplexed input signals into the reservoir, and show how this allows us to perform machine learning tasks including: the classification of (1) sine and square waves; (2) spoken digits; and (3) non-temporal 2D toy data and hand written digits. Our work lays the foundation for the creation of nanoscale neuromorphic devices in which individual magnetic domain walls are used to perform complex data analysis tasks.

An Eastern Association for the Surgery of Trauma multicenter trial examining prehospital procedures in penetrating trauma patients.

BACKGROUND: Prehospital procedures (PHP) by emergency medical services (EMS) are performed regularly in penetrating trauma patients despite previous studies demonstrating no benefit. We sought to examine the influence of PHPs on outcomes in penetrating trauma patients in urban locations where transport to trauma center is not prolonged. We hypothesized that patients without PHPs would have better outcomes than those undergoing PHP. METHODS: This was an Eastern Association for the Surgery of Trauma-sponsored, multicenter, prospective, observational trial of adults (18+ years) with penetrating trauma to the torso and/or proximal extremity presenting at 25 urban trauma centers. The impact of PHPs and transport mechanism on in-hospital mortality were examined. RESULTS: Of 2,284 patients included, 1,386 (60.7%) underwent PHP. The patients were primarily Black (n = 1,527, 66.9%) males (n = 1,986, 87.5%) injured by gunshot wound (n = 1,510, 66.0%) with 34.1% (n = 726) having New Injury Severity Score of ≥16. A total of 1,427 patients (62.5%) were transported by Advanced Life Support EMS, 17.2% (n = 392) by private vehicle, 13.7% (n = 312) by police, and 6.7% (n = 153) by Basic Life Support EMS. Of the PHP patients, 69.1% received PHP on scene, 59.9% received PHP in route, and 29.0% received PHP both on scene and in route. Initial scene vitals differed between groups, but initial emergency department vitals did not. Receipt of ≥1 PHP increased mortality odds (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.01-1.83; p = 0.04). Logistic regression showed increased mortality with each PHP, whether on scene or during transport. Subset analysis of specific PHP revealed that intubation (OR, 10.76; 95% CI, 4.02-28.78; p < 0.001), C-spine immobilization (OR, 5.80; 95% CI, 1.85-18.26; p < 0.01), and pleural decompression (OR, 3.70; 95% CI, 1.33-10.28; p = 0.01) had the highest odds of mortality after adjusting for multiple variables. CONCLUSION: Prehospital procedures in penetrating trauma patients impart no survival advantage and may be harmful in urban settings, even when performed during transport. Therefore, PHP should be forgone in lieu of immediate transport to improve patient outcomes. LEVEL OF EVIDENCE: Prognostic, level III.

The impact of country and culture on end-of-life care for injured patients: results from an international survey.

BACKGROUND: Up to 20% of all trauma patients admitted to an intensive care unit die from their injuries. End-of-life decision making is a variable process that involves prognosis, predicted functional outcomes, personal beliefs, institutional resources, societal norms, and clinician experience. The goal of this study was to better understand end-of-life processes after major injury by comparing clinician viewpoints from various countries and cultures. METHODS: A clinician-based, 38-question international survey was used to characterize the impacts of medical, religious, social, and system factors on end-of-life care after trauma. RESULTS: A total of 419 clinicians from the United States (49%), Canada (19%), South Africa (11%), Europe (9%), Asia (8%), and Australasia (4%) completed the survey. In America, the admitting surgeon guided most end-of-life decisions (51%), when compared with all other countries (0-27%). The practice structure of American respondents also varied from other regions. Formal medical futility laws are rarely available (14-38%). Ethical consultation services are often accessible (29-98%), but rarely used (0-29%), and typically unhelpful (<30%). End-of-life decision making for patients with traumatic brain injuries varied extensively across regions with regard to the impact of patient age, Glasgow Coma Scale score, and clinician philosophy. Similar differences were observed for spinal cord injuries (age and functional level). The availability and use of "donation after cardiac death" also varied substantially between countries. CONCLUSIONS: In this unique study, geographic differences in religion, practice composition, decision-maker viewpoint, and institutional resources resulted in significant variation in end-of-life care after injury. These disparities reflect competing concepts (patient autonomy, distributive justice, and religion).

Evidence-based review of trauma center care and routine palliative care processes for geriatric trauma patients; A collaboration from the American Association for the Surgery of Trauma Patient Assessment Committee, the American Association for the Surgery of Trauma Geriatric Trauma Committee, and the Eastern Association for the Surgery of Trauma Guidelines Committee.

BACKGROUND: Despite an aging population and increasing number of geriatric trauma patients annually, gaps in our understanding of best practices for geriatric trauma patients persist. We know that trauma center care improves outcomes for injured patients generally, and palliative care processes can improve outcomes for disease-specific conditions, and our goal was to determine effectiveness of these interventions on outcomes for geriatric trauma patients. METHODS: A priori questions were created regarding outcomes for patients 65 years or older with respect to care at trauma centers versus nontrauma centers and use of routine palliative care processes. A query of MEDLINE, PubMed, Cochrane Library, and EMBASE was performed. Letters to the editor, case reports, book chapters, and review articles were excluded. GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to perform a systematic review and create recommendations. RESULTS: We reviewed seven articles relevant to trauma center care and nine articles reporting results on palliative care processes as they related to geriatric trauma patients. Given data quality and limitations, we conditionally recommend trauma center care for the severely injured geriatric trauma patients but are unable to make a recommendation on the question of routine palliative care processes for geriatric trauma patients. CONCLUSIONS: As our older adult population increases, injured geriatric patients will continue to pose challenges for care, such as comorbidities or frailty. We found that trauma center care was associated with improved outcomes for geriatric trauma patients in most studies and that utilization of early palliative care consultations was generally associated with improved secondary outcomes, such as length of stay; however, inconsistency and imprecision prevented us from making a clear recommendation for this question. As caregivers, we should ensure adequate support for trauma systems and palliative care processes in our institutions and communities and continue to support robust research to study these and other aspects of geriatric trauma. LEVEL OF EVIDENCE: Systematic review/guideline, level III.

Habitual tool use innovated by free-living New Zealand kea.

The emergence of flexible tool use is rare in the animal kingdom and thought to be largely constrained by either cognitive ability or ecological factors. That mostly birds with a high level of intelligence innovate tool use in captivity is consistent with the former hypothesis. We report here the first documented case of habitual tool use innovated in the wild by a bird species only known to have used tools in captivity. Trap-boxes containing food-bait and snap-trap(s) were installed in the remote Murchison Mountains, New Zealand, from 2002 to catch introduced stoats. Kea tampered with the trap-boxes in various ways. Over approximately 2.5 years, sticks were found inserted into at least 227 different trap-boxes that were up to 27 km apart. Video footage confirmed that the stick insertion was kea tool use. Trap-boxes are unlikely to have provided the only possibility for kea tool use in their habitat given their extractive foraging and skilled object manipulation. We argue that they instead greatly facilitated the opportunity for tool use, thus increasing the chance that kea would invent the behaviour. The innovation of tool use by kea in response to facilitation provides rare field support for the cognitive constraints hypothesis.

Implementation of antibiotic rotation protocol improves antibiotic susceptibility profile in a surgical intensive care unit.

BACKGROUND: Antibiotic rotation has been proposed as a way to potentially reduce the development of antimicrobial resistant bacteria in intensive care units. We assessed the effect of an antibiotic rotation protocol on the antibiotic susceptibility profiles of three clinically relevant gram-negative microorganisms within our surgical intensive care unit (SICU). METHODS: Our SICU implemented an antibiotic rotation protocol in 2003. Four antibiotics (piperacillin/tazobactam, imipenem/cilastin, ceftazidime, and ciprofloxacin) were rotated as the primary antibiotic used to treat suspected gram-negative infections every month, with the four-drug cycle being repeated every 4 months. Antibiotic susceptibility data for three microorganisms (Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae) were collected for the year before (2002) and the year after (2004) the implementation of the rotation protocol. Changes in antimicrobial susceptibility rates were analyzed for the three microorganisms. As a comparison, a similar analysis was conducted for microorganisms isolated from our medical intensive care unit, where no antibiotic rotation protocol was implemented. RESULTS: Implementation of an antibiotic rotation protocol in our SICU resulted in a significant increase in the percentage of P. aeruginosa isolates sensitive to ceftazidime (67% in 2002 vs. 92% in 2004, p = 0.002) and piperacillin/tazobactam (78% in 2002 vs. 92% in 2004, p = 0.043). Isolates from the medical intensive care unit did not demonstrate an increase in antimicrobial susceptibility. In fact, the susceptibility of E. coli to piperacillin/tazobactam decreased during this time period (p = 0.047). CONCLUSIONS: Implementation of an antibiotic rotation protocol in our SICU resulted in overall improvement in the antibiotic susceptibility profile of gram-negative microorganisms relative to our medical intensive care unit, where such a protocol was not used.

Single- and multi-channel underwater acoustic communication channel capacity: a computational study.

Acoustic communication channel capacity determines the maximum data rate that can be supported by an acoustic channel for a given source power and source/receiver configuration. In this paper, broadband acoustic propagation modeling is applied to estimate the channel capacity for a time-invariant shallow-water waveguide for a single source-receiver pair and for vertical source and receiver arrays. Without bandwidth constraints, estimated single-input, single-output (SISO) capacities approach 10 megabitss at 1 km range, but beyond 2 km range they decay at a rate consistent with previous estimates by Peloquin and Leinhos (unpublished, 1997), which were based on a sonar equation calculation. Channel capacities subject to source bandwidth constraints are approximately 30-90% lower than for the unconstrained case, and exhibit a significant wind speed dependence. Channel capacity is investigated for single-input, multi-output (SIMO) and multi-input, multi-output (MIMO) systems, both for finite arrays and in the limit of a dense array spanning the entire water column. The limiting values of the SIMO and MIMO channel capacities for the modeled environment are found to be about four times higher and up to 200-400 times higher, respectively, than for the SISO case. Implications for underwater acoustic communication systems are discussed.

A cost and outcomes comparison of a novel integrated pediatric air and ground transportation system.

BACKGROUND: The purpose of this study is to compare air transportation of critically ill pediatric patients with a mixed air-ground transportation system by evaluating timeliness, safety, and cost. The setting was a tertiary care "hub" center with three outlying-referral "spoke" facilities. STUDY DESIGN: Our study included 96 children transported between June and December 1997, with 45% constituting surgical admissions and 55% medical admissions. Data collected at the outlying facilities, en route, and at our institution included vital signs, laboratory values, and Glasgow coma scores. We evaluated transport time, transport cost, Pediatric Risk of Mortality scores, and Pediatric Index of Mortality of the children during transportation using ANOVA statistical analysis. We also compared adverse events in transportation, total hospital length of stay, and mortality at 24 and 72 hours in both the air and ground transport groups to determine differences in predicted and observed mortality. RESULTS: A total of 96 children were transported (48% by ground and 52% by air) between June and December 1997. The time at the referring facility was significantly shorter in the ground group than in the air group (air, 55.4 minutes versus ground, 36.7 minutes, p < 0.01). Total transport time differed by only 27 minutes between groups. No difference was identified in morbidity or mortality between air and ground groups. Actual mortality was not significantly different from predicted mortality in either group. The cost of ground transportation was significantly lower (air, $4,236 versus ground, $1,566). When our system of a combined air and ground group transport system is compared with a hypothetical 100% air transport system, we saved an average of more than $240,000 annually. CONCLUSIONS: We have demonstrated that a "hub-and-spoke" ground transportation system supplements air transportation in a safe, timely, and cost-effective manner.

Hemodynamic monitoring in the intensive care unit.

Patients in the intensive care unit are often critically ill with inadequate tissue perfusion and oxygenation. This inadequate delivery of substrates at the cellular level is a common definition of shock. Hemodynamic monitoring is the observation of cardiovascular physiology. The purpose of hemodynamic monitoring is to identify abnormal physiology and intervene before complications, including organ failure and death, occur. The most common types of invasive hemodynamic monitors are central venous catheters, pulmonary artery catheters, and arterial pulse-wave analysis. Ultrasonography is a noninvasive alternative being used in intensive care units for hemodynamic measurements and assessments.