Trauma care regionalization: a process-outcome evaluation

BACKGROUND

Regionalization of trauma care services in our region was initiated in 1993 with the designation of four tertiary trauma centers. The process continued in 1995 with the implementation of patient triage and transfer protocols. Since 1995, the network of trauma care has been expanded with the designation of 33 secondary, 30 primary, and 32 stabilization trauma centers. In addition, during this period emergency medical personnel have been trained to assess and triage trauma victims within minimal prehospital time. The objective of the present study was to evaluate the impact of trauma care regionalization on the mortality of major trauma patients.

METHODS

This was a prospective study in which patients were entered at the time of injury and were followed to discharge from the acute-care hospital. The patients were identified from the Quebec Trauma Registry, a review of the records of acute-care hospitals that treat trauma, and records of the emergency medical services in the region. The study sample consisted of all patients fulfilling the criteria of a major trauma, defined as death, or Injury Severity Score (ISS) > 12, or Pre-Hospital Index > 3, or two or more injuries with Abbreviated Injury Scale scores > 2, or hospital stay of more than 3 days. Data collection took place between April 1, 1993, and March 31, 1998. During this period, four distinct phases of trauma care regionalization were defined: pre-regionalization (phase 0), initiation (phase I), intermediate (phase II), and advanced (phase III).

RESULTS

A total of 12,208 patients were entered into the study cohort, and they were approximately evenly distributed over the 6 years of the study. During the study period, there was a decline in the mean age of patients from 54 to 46 years, whereas the male/female ratio remained constant at 2:1. There was also an increase in the mean ISS, from 25.5 to 27.5. The proportion of patients injured in motor vehicle collisions increased from less than 45% to more than 50% (p < 0.001). The mortality rate during the phases of regionalization were: phase 0, 52%; phase I, 32%; phase II, 19%; and phase III, 18%. These differences were clinically important and statistically significant (p < 0.0001). Stratified analysis showed a significant decline in mortality among patients with ISS between 12 and 49. The change in mortality for patients with fatal injuries (ISS > or = 50) was not significant. During the study period, the mean prehospital time decreased significantly, from 62 to 44 minutes. The mean time to admission after arrival at the hospital decreased from 151 to 128 minutes (p < 0.001). The latter decrease was primarily attributable to changes at the tertiary centers. The proportion of patients with ISS between 12 and 24 and between 25 and 49 who were treated at tertiary centers increased from 56 to 82% and from 36 to 84%, respectively (p < 0.001). Compared with the secondary and primary centers, throughout the course of the study the mortality rate in the secondary and tertiary centers showed a consistent decline (p < 0.001). In addition, the mortality rate in the tertiary centers remained consistently lower (p < 0.001). The results of multivariate analyses showed that after adjusting for injury severity and patient age, the primary factors contributing to the reduced mortality were treatment at a tertiary center, reduced prehospital time, and direct transport from the scene to tertiary centers.

CONCLUSION

This study produced empirical evidence that the integration of trauma care services into a regionalized system reduces mortality. The results showed that tertiary trauma centers and reduced prehospital times are the essential components of an efficient trauma care system.

Impact of on-site care, prehospital time, and level of in-hospital care on survival in severely injured patients

A sample of 360 severely injured patients was selected from a cohort of 8007 trauma victims followed prospectively from the time of injury to death or discharge. A case referent study was used to test the association between on-site care, total prehospital time, and level of care at the receiving hospital with short-term survival. Multiple logistic regression analyses showed that use of Advanced Life Support (ALS) at the scene was not associated with survival, whereas treatment at a level I compatible hospital was associated with a 38% reduction in the odds of dying, which approached statistical significance. Total prehospital time over 60 minutes was associated with a statistically significant adjusted relative odds of dying (OR = 3.0). The results of this study support the need for regionalization of trauma care and fail to show a benefit associated with ALS.

A simple method to detect expiratory flow limitation during spontaneous breathing

Patients with severe chronic obstructive pulmonary disease (COPD) often exhale along the same flow-volume curve during quiet breathing as during a forced expiratory vital capacity manoeuvre, and this has been taken as indicating flow limitation at rest. To obtain such curves, a body plethysmograph and the patient's co-operation are required. We propose a simple technique which does not entail these requirements. It consists in applying negative pressure at the mouth during a tidal expiration (NEP). Patients in whom NEP elicits an increase in flow throughout the expiration are not flow-limited. In contrast, patients in whom application of NEP does not elicit an increase in flow during most or part of the tidal expiration are considered as flow-limited. Using this technique, 26 stable COPD patients were studied sitting and supine. Eleven patients were flow-limited both seated and supine, eight were flow-limited only when supine, and seven were not flow-limited either seated or supine. Only 5 of 19 patients who were flow-limited seated and/or supine had severe ventilatory impairment (forced expiratory volume in one second (FEV1) < 40% predicted). We conclude that the NEP technique provides a simple, rapid, and reliable method for detection of expiratory flow limitation in spontaneously breathing subjects, which does not require the patient's co-operation, and can be applied in different body positions both at rest and during muscular exercise. Our results also indicate a high prevalence of flow limitation in COPD patients at rest, particularly when supine.

Sedation of critically ill patients during mechanical ventilation. A comparison of propofol and midazolam

Propofol (P) and midazolam (M) are frequently given by continuous infusion for sedation in critically ill, mechanically ventilated patients. We compared these drugs with regard to: (1) time-to-awaken; (2) reproducibility of bedside assessments of level of sedation; (3) time-to-sedation; and (4) change in oxygen consumption (V O2) from awake to sedated state. Seventy-three patients were prospectively randomized to receive either P (n=37) or M (n=36). Wake-up times after stopping the drug were assessed by blinded and unblinded observers, by asking patients to perform simple tasks. Times to sedate were assessed by consensus agreement among nurses and investigators. Demographics and APACHE II scores were not different between P and M. The P group had a significantly narrower range of wake-up times with a higher likelihood of waking in less than 60 min. Blinded versus unblinded observations had excellent correlation. Average time to sedate and decrease in V O2 were not different. We conclude that in this patient population: (1) both P and M achieved optimal sedation in a large fraction of patients when administered by specified dosing protocols; (2) P had a faster, more reliable, wake-up time; (3) assessments of time-to-awaken were objective and reproducible; (4) time to sedation was not significantly different; (5) V O2 decreased similarly with both.

Response to inhaled nitric oxide in patients with acute right heart syndrome

Inhaled nitric oxide (iNO), a selective pulmonary vasodilator, has been shown to decrease pulmonary artery pressures but not increase cardiac output in hemodynamically stable patients with a variety of causes of pulmonary hypertension. The response to iNO in hemodynamically unstable patients with acute right heart syndrome has not been previously described. We determined the response to iNO in 26 critically ill adult patients with acute right heart failure defined by echocardiographic criteria. Patients received iNO through the inspiratory limb of the ventilator in increments of 10 ppm with hemodynamic and gas-exchange measurements made before and after each level. When maximal effect was seen, iNO was discontinued to compare parameters with baseline. iNO significantly increased cardiac output (5.5 +/- 3 to 6.4 +/- 4 L/min), stroke volume (54 +/- 27 to 65 +/- 38 ml), and mixed-venous oxygen saturation (69 +/- 8 to 73 +/- 10%), all p < 0.01. With discontinuation of iNO, all parameters returned immediately to baseline. These parameters of improved perfusion were related to a decrease in pulmonary vascular pressures and resistance. In a subset of approximately 50% of patients, these changes were substantial (> 20%) and in approximately 25% of all patients, the improvement in hemodynamic measures permitted a decrease in other vasoactive drug administration. The mean concentration of iNO required to achieve these effects was 35 ppm, and 85% of patients exhibiting a substantial improvement in hemodynamics did so at a concentration of iNO of less than or equal to 40 ppm. Underlying causes of right heart failure and baseline hemodynamics did not predict response to iNO, but the use of alpha-agonist catecholamines did. We conclude iNO improves hemodynamics in patients with respiratory failure, shock, and right ventricular dysfunction. Although mortality was not a key end point in this pilot study, it was high for both responders and nonresponders to this therapy. Further evaluation of the role of iNO in this patient population is supported by these data.

Detection of expiratory flow limitation during mechanical ventilation

Two new methods, application of negative pressure at the airway opening during expiration (NEP) and reduction of flow resistance by bypassing the expiratory line of the ventilator by exhaling into the atmosphere (ATM), were used to detect expiratory flow limitation in 12 semirecumbent (45 degree) mechanically ventilated patients, seven with chronic airway obstruction (CAO). An increase of expiratory flow with NEP or ATM, relative to the preceding control breath, was taken as indicating absence of expiratory flow limitation. By contrast, the portion of the tidal expiration over which there was no change in flow with NEP or ATM was considered as flow-limited. With NEP, nine patients exhibited flow limitation, six (all with CAO) were flow-limited over most of the tidal expiration (> 70% VT), and three at < 60% VT. Although the results with NEP and ATM were in general in good agreement, in the three non-flow-limited patients the ATM method gave erroneous results. Six patients were also studied supine, including two who were not flow-limited when semirecumbent: both became flow-limited when supine. We conclude that NEP provides a simple method to detect flow limitation in mechanically ventilated patients. The supine position enhances flow limitation.

Life-threatening effects of discontinuing inhaled nitric oxide in severe respiratory failure

We present the effects of abrupt discontinuation of inhaled nitric oxide (NO) in four patients with severe hypoxemic respiratory failure. These patients ranged from 9 mo to 65 yr of age. In each patient, after the initiation of inhaled NO, a marginal, but immediate, beneficial effect on gas exchange and, when measured, a reduction in pulmonary artery pressures was noted. However, during attempts to discontinue inhaled NO, not only did these patients develop worsening oxygenation and recrudescence of pulmonary hypertension but, unexpectedly, these parameters were worse than the baseline values, leading to life-threatening hemodynamic instability. These effects reversed immediately after reinstitution of inhaled NO. The mechanism of this severe ¿rebound¿ in pulmonary hypertension after abrupt withdrawal of NO is unclear, but its existence emphasizes the need to avoid a substantial risk to these patients. Moreover, we believe that both unintentional and intentional termination of inhaled NO therapy may lead to life-threatening deterioration in gas exchange and circulatory hemodynamics that exceeds the initial therapeutic benefit.

Mutations in activation-induced cytidine deaminase in patients with hyper IgM syndrome

Recent studies have shown that mutations in a newly described RNA editing enzyme, activation-induced cytidine deaminase (AID), can cause an autosomal recessive form of hyper IgM syndrome. To determine the relative frequency of mutations in AID, we evaluated a group of 27 patients with hyper IgM syndrome who did not have defects in CD40 ligand and 23 patients with common variable immunodeficiency. Three different mutations in AID were identified in 18 patients with hyper IgM syndrome, including 14 French Canadians, 2 Lumbee Indians, and a brother and sister from Okinawa. No mutations were found in the remaining 32 patients. In the group of patients with hyper IgM syndrome, the patients with mutations in AID were older at the age of diagnosis, were more likely to have positive isohemagglutinins, and were less likely to have anemia, neutropenia, or thrombocytopenia. Lymphoid hyperplasia was seen in patients with hyper IgM syndrome and normal AID as well as the patients with hyper IgM syndrome and defects in AID.

Trauma center designation: initial impact on trauma-related mortality

The movement towards trauma care regionalization in Québec was initiated in 1990, with formal designation of three level I trauma centers in 1993. The purpose of this study is to evaluate the impact of trauma center designation on mortality. The study design is that of a two-cohort study, one assembled during 1987 when designation was not in effect, and the other during the first 5 months of designation. The study focuses on patients that fulfilled the following criteria: i) arrived alive at the hospital, and ii) were admitted. The outcome measures are adjusted mortality, and excess mortality as measured by the TRISS methodology. A total of 158 patients treated in 1987, and 288 treated in 1993, were identified. The mean age of the patients treated in 1993 was significantly higher (40.0, +/- 18.1), when compared with the 1987 group (30.9 +/- 18.1; p < 0.001). Patients in the 1987 cohort had a significantly higher proportion of injuries caused by stabbing (p = 0.02), and a significantly lower proportion caused by falls (p = 0.003). The 1987 cohort had a higher rate of abdominal injuries (p = 0.0001), and external injuries (p = 0.0001), and a significantly lower rate of head or neck injuries (p = 0.003), and injuries to the extremities (p = 0.0001). The mean Injury Severity Score (ISS) for the 1987 cohort was 14.96 (+/- 12.36), and 15.49 (+/- 11.61) in 1993 (p = 0.65). The crude mortality rate was 20% for 1987, and 10% for 1993. The crude odds ratio for mortality in 1987 was 2.10 with 95% confidence intervals between 1.22 and 3.62 (p = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Nonrandom X chromosome inactivation in B cells from carriers of X chromosome-linked severe combined immunodeficiency

X chromosome-linked severe combined immunodeficiency (XSCID) is characterized by markedly reduced numbers of T cells, the absence of proliferative responses to mitogens, and hypogammaglobulinemia but normal or elevated numbers of B cells. To determine if the failure of the B cells to produce immunoglobulin might be due to expression of the XSCID gene defect in B-lineage cells as well as T cells, we analyzed patterns of X chromosome inactivation in B cells from nine obligate carriers of this disorder. A series of somatic cell hybrids that selectively retained the active X chromosome was produced from Epstein-Barr virus-stimulated B cells from each woman. To distinguish between the two X chromosomes, the hybrids from each woman were analyzed using an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. In all obligate carriers of XSCID, the B-cell hybrids demonstrated preferential use of a single X chromosome, the nonmutant X, as the active X. To determine if the small number of B-cell hybrids that contained the mutant X were derived from an immature subset of B cells, lymphocytes from three carriers were separated into surface IgM positive and surface IgM negative B cells prior to exposure to Epstein-Barr virus and production of B-cell hybrids. The results demonstrated normal random X chromosome inactivation in B-cell hybrids derived from the less mature surface IgM positive B cells. In contrast, the pattern of X chromosome inactivation in the surface IgM negative B cells, which had undergone further replication and differentiation, was significantly nonrandom in all three experiments [logarithm of odds (lod) score greater than 3.0]. These results suggest that the XSCID gene product has a direct effect on B cells as well as T cells and is required during B-cell maturation.

Ineffectiveness of on-site intravenous lines: is prehospital time the culprit?

The purpose of the present study was to test the association between on-site intravenous fluid replacement and mortality in patients with severe trauma. The effect of prehospital time on this association was also evaluated. The design was that of an observational quasi-experimental study comparing 217 patients who had on-site intravenous fluid replacement (IV group) with an equal number of matched patients for whom this intervention was not performed (no-IV group). The patients were individually matched on their Prehospital Index obtained at the scene and were included in the study if they had an on-site Prehospital Index score > 3 and were transported alive to the hospital. The outcome measure of interest was mortality because of injury. The patients in the IV group had a significantly lower mean age (37 vs. 45 years; p < 0.001) and higher incidence of injuries to the head or neck (46 vs. 32%; p = 0.004), chest (34 vs. 17%; p < 0.001), and abdomen (28 vs. 12%; p < 0.001). The IV group also had a higher proportion of patients injured by motor vehicle crashes (41 vs. 27%; p = 0.003), firearms (9 vs. 2%; p = 0.001), and stabbing (20 vs. 9%; p = 0.001). The rate of extremity injuries (38 vs. 59%; p < 0.001) and falls (12 vs. 40%; p < 0.001) was lower for the IV group. In addition, the mean Injury Severity Score was significantly higher for the IV group (15 vs. 9; p < 0.001). The mortality rates for the IV and no-IV groups were 23 and 6% (p < 0.001). Logistic regression analysis showed that after adjusting for patient age, gender, Injury Severity Score, mechanism of injury, and prehospital time, the use of on-site intravenous fluid replacement was associated with a significant increase in the risk of mortality (adjusted odds ratio = 2.3; 95% confidence interval = 1.02-5.28; p = 0.04). To further evaluate the effect of prehospital time on the association between on-site IV use and mortality, the analysis was repeated separately for the following time strata: 0 to 30 minutes, 31 to 60 minutes, and >60 minutes. The adjusted odds ratios (95% confidence interval) for these strata were 1.05 (0.08-14.53; p = 0.97), 3.38 (0.84-13.62; p = 0.08), and 8.40 (1.27-54.69; p = 0.03). These results show that for prehospital times of less than 30 minutes, the use of on-site intravenous fluid replacement provides no benefit, and that for longer times, this intervention is associated with significant increases in the risk of mortality. The results of this observational study have shown that the use of on-site intravenous fluid replacement is associated with an increase in mortality risk and that this association is exacerbated by, but is not solely the result of, increased prehospital times. Our findings are consistent with the hypothesis that early intravenous fluid replacement is harmful because it disrupts the normal physiologic response to severe bleeding. Although this evidence is against the implementation of on-site intravenous fluid replacement for severely injured patients, further studies including randomized controlled trials are required to provide a definitive answer to this question.

Diabetes: a major co-morbidity of cystic fibrosis

Cystic fibrosis-related diabetes (CFRD) is a frequent complication of cystic fibrosis, its prevalence increases with age of patient and is close to 30% at the age of 30 years. As life expectancy greatly increases, the number of cystic fibrosis patients developing diabetes will increase too. CFRD shares some features with type 1 and type 2 diabetes, initial phase is characterised by postprandial hyperglycaemia followed by a progression toward insulin deficiency. Insulin deficiency is an essential factor in the development of diabetes with an additional contribution of insulin resistance. Systematic screening with an oral glucose tolerance test is recommended from the age of 14 years because clinical signs of CFRD are often confused with signs of pulmonary infection and CFRD occurrence is associated with weight and pulmonary function deterioration. In observational studies CFRD diagnosis is associated with a significant increase in mortality, while treatment allow correction of weight and lung deterioration suggesting that CFRD has a significant impact on CF evolution. Microvascular complications are recognised, although paucity of data does not permit a clear description of their natural history. Annual screening for microvascular complication is recommended. There is no evidence by now that CF patients develop macrovascular complications. The only recommended pharmacological treatment is insulin therapy.

The incidence and pathogenesis of cardiopulmonary deterioration after abrupt withdrawal of inhaled nitric oxide

We studied the effect of abrupt discontinuation of inhaled nitric oxide (iNO) in patients receiving this drug for treatment of acute hypoxemic respiratory failure (AHRF), in order to determine the need for continued therapy, the incidence and nature of adverse events, and the risk factors predicting these adverse events. Thirty-one patients who showed an initial increase in Pa(O(2)) of > 20 mm Hg in response to iNO underwent a discontinuation trial at 10 to 30 h after beginning iNO. Indwelling arterial and pulmonary artery catheters facilitated monitoring of hemodynamic and gas-exchange parameters. For the group, discontinuation of iNO caused a significant decrease in Pa(O2 ), arterial and mixed venous oxygen saturation, and ratio of Pa(O(2)) to fraction of inspired oxygen (FI(O(2))). Three patterns of response were observed. Eight of 31 (25.8%) patients had minimal changes in oxygenation or hemodynamics, suggesting no need for ongoing therapy. Fifteen of 31 (48%) patients had worsened gas exchange as a predominant response. Eight of 31 patients exhibited hemodynamic collapse, defined as > 20% fall in cardiac output and/or mean arterial blood pressure. In this last subgroup, the pattern of cardiovascular changes suggested that this response arose from an acute increase in right ventricular afterload, and was not a consequence of gas-exchange abnormalities. In all cases, reinstitution of iNO promptly reversed worsened hemodynamics and gas exchange. Independent factors associated with an increased risk of cardiovascular collapse included multisystem organ failure, older age, and initial blood pressure increase in response to iNO; a smaller change in the ratio of Pa(O(2)) to FI(O(2)) with initiation of iNO therapy also tended to correlate with this phenomenon. We conclude that careful and monitored discontinuation of iNO in patients with AHRF will identify substantial fractions of patients who are either receiving no benefit from this therapy or who require iNO to maintain an adequate circulation and are therefore at risk for adverse outcome with transport or inadvertent discontinuation of iNO. Future trials of iNO should recognize this complication of such therapy and include assessments for it.

Cardiopulmonary resuscitation: errors made by pre-hospital emergency medical personnel

The purpose of the current study was to evaluate the CPR techniques of emergency healthcare professionals (emergency medical technicians, firemen, emergency first responders, CPR instructors). Skills were evaluated using a Laerdal Skillmeter Manikin, which provided a computerized printout of the quantifiable data during the CPR sequence. All of the 66 subjects in the study had completed a recertification course within the last 2 years (mean = 0.86 +/- 0.18, 95% CI). The sequence was videotaped for later viewing and for correlating the errors with the data. In addition, the participants were required to fill in a questionnaire. The most frequently occurring errors were observed in landmarking, overcompression, palpating a carotid pulse and insufficient ventilation. Although 98.5% of participants made an attempt to landmark their position for compression on the sternum, 35.9% of the total compressions performed by all subjects were incorrectly positioned on the patient's chest. Overcompression of the patient's chest accounted for 55.3% of incorrect compressions. Although 94% of participants attempted to verify a carotid pulse, only 45% were able to feel it and therefore stop performing cardiac massage. Of the total ventilations, 49% were below the American Heart Association (AHA) recommended minimum (800 ml). The results of this study showed a high rate of errors occurring in the CPR provided by emergency healthcare professionals.

Chronic idiopathic urticaria: profiles of skin mast cell histamine release during active disease and remission

Chronic idiopathic urticaria (CIU) is characterized by the increased releasability of histamine by mast cells in normal-appearing skin. In active CIU, this abnormality is consistently present. To determine if this finding subsides when the disease goes into remission phase, we analyzed the histamine secretion in patients with CIU in remission (CIUR) compared with that of patients with CIU and in normal control (NC) subjects, with the skin-chamber technique. The profiles of histamine release in sites challenged with compound 48/80 were significantly different in the groups with CIU and CIUR. Furthermore, patients with CIUR did not differ from NC subjects in terms of histamine releasability under compound 48/80 stimulation (p greater than 0.1). These data suggest that the state of excessive skin mast cell sensitivity is a reversible and transient phenomenon in CIU disease.

Allergic rhinitis to ragweed pollenI. Reassessment of the effects of immunotherapy on cellular and humoral responses

This work presents a double-blind, placebo-controlled study of 27 patients with allergic rhinitis to ragweed who received preseasonal desensitization immunotherapy [IT] with alum-precipitated aqueous ragweed extracts. We reassessed the following parameters in relation to clinical responses: clinical scores, nasal reactivity to a provocative dose of ragweed causing a 75% fall in airflow rate (PD75), ragweed IgE and IgG, and ragweed-induced basophil histamine release (BHR). First, the nasal PD75 correlated with the severity of nasal symptoms (p less than 0.05). Second, we confirmed a significant symptomatic improvement in the IT-treated group either by clinical scores (p less than 0.05) or the prevention of the seasonal fall of the PD75 (p less than 0.005). Also, IT reduced the seasonal rise of IgE (p less than 0.02) and induced an increase in IgG (p less than 0.01) and a decrease in BHR (p less than 0.03). There was a significant correlation between IgE and BHR (r = 0.80; p less than 0.01). After selecting out the effects of IgE, the BHR was still higher in the placebo-treated group than in the IT-treated group (p less than 0.02), suggesting the involvement of other modulating factors. Symptomatic improvement after IT correlated only with the summation of both IgE and BHR (PD75; r = 0.64; p less than 0.005). This observation suggests that the severity of clinical symptoms is determined by several interacting factors and not by the antibody response alone.

Light Up the Brain: The Application of Optogenetics in Cell-Type Specific Dissection of Mouse Brain Circuits

The exquisite intricacies of neural circuits are fundamental to an animal’s diverse and complex repertoire of sensory and motor functions. The ability to precisely map neural circuits and to selectively manipulate neural activity is critical to understanding brain function and has, therefore been a long-standing goal for neuroscientists. The recent development of optogenetic tools, combined with transgenic mouse lines, has endowed us with unprecedented spatiotemporal precision in circuit analysis. These advances greatly expand the scope of tractable experimental investigations. Here, in the first half of the review, we will present applications of optogenetics in identifying connectivity between different local neuronal cell types and of long-range projections with both in vitro and in vivo methods. We will then discuss how these tools can be used to reveal the functional roles of these cell-type specific connections in governing sensory information processing, and learning and memory in the visual cortex, somatosensory cortex, and motor cortex. Finally, we will discuss the prospect of new optogenetic tools and how their application can further advance modern neuroscience. In summary, this review serves as a primer to exemplify how optogenetics can be used in sophisticated modern circuit analyses at the levels of synapses, cells, network connectivity and behaviors.

Preventable death evaluation of the appropriateness of the on-site trauma care provided by Urgences-Santé physicians

The study is based on 44 preventable deaths occurring in a cohort of 360 patients with major trauma. These cases were reviewed by a committee of nine experts. The mean Injury Severity Score (ISS) was 28, and most cases had injuries to the head/neck (68%) and chest (64%). The mean (+/- SD) observed prehospital times, and those considered the maximum allowable by the committee, were 40.6 +/- 12.0 minutes for head/neck injuries and 23.9 +/- 12.2 minutes for chest injuries (p < 0.05). Intravenous (i.v.) lines were started in 38 (86%) of the patients. The committee classified this procedure as harmful for 16 (42%) and neutral for 19 (50%). Among the 18 (46%) that were intubated, this intervention was considered harmful for 17% and neutral for 39%. In two of the three patients for whom a pneumatic antishock garment was applied, this procedure was considered harmful. Of the 34 patients that required direct transport at a level I trauma center, 50% were transferred to such a hospital. These results show significant prehospital delays and high rates of inappropriate IV line initiation and intubation in trauma patients receiving on-site care by physicians. We conclude that prehospital care protocols for trauma patients should emphasize prompt transport and specific on-site care algorithms.

Allergic rhinitis to ragweed pollen. II. Modulation of histamine-releasing factor production by specific immunotherapy

A number of cytokines, including histamine-releasing factors (HRFs), have a role to play in IgE-mediated asthma. However, the influence of HRF in allergic rhinitis without asthma remains to be revealed. This article presents a double-blind, placebo-controlled study on the role of HRF in ragweed-allergic rhinitis and its modulation by natural pollen exposure and specific immunotherapy (IT). Twenty-seven patients allergic to ragweed were randomly assigned to receive either preseasonal alum-precipitated aqueous extracts of ragweed or placebo. Before the onset of therapy and during the ragweed-pollen season, subjects were evaluated for each of the following: clinical scores, ragweed IgE and IgG antibody levels, and spontaneous and allergen-driven HRF production. Thirteen nonatopic volunteers were also studied in the same protocol. First, before the initiation of therapy, more HRF was produced by both unstimulated and ragweed-stimulated mononuclear cells (MNCs) of atopic subjects as compared to MNCs of nonatopic subjects. Second, MNCs of the placebo-treated group produced significantly more spontaneous and ragweed-specific HRF during the pollen season compared to the preseasonal values. Finally, specific IT not only improved the clinical manifestation of allergy but also prevented the seasonal rise of spontaneous and ragweed-driven HRF production, along with a well-known change in other immunologic parameters associated with successful IT.

Standardized mortality ratio analysis on a sample of severely injured patients from a large Canadian city without regionalized trauma care

Flora's Z statistic and standardized mortality ratios (SMRs) as indicators of excess mortality were calculated for a sample of 355 patients with major trauma. A statistically significant overall excess mortality was observed in this sample (Z = 6.77, SMR = 1.81, p less than 0.05). Advanced life support provided by physicians at the scene (MD-ALS) was not associated with reduced excess mortality. A significant trend toward lower excess mortality was associated with a higher level of trauma care at the receiving hospital (p less than 0.05). Total prehospital time over 60 minutes was associated with a significant increase in excess mortality (p less than 0.001). These results support regionalization of trauma care and failed to show any benefit associated with MD-ALS.