Hypothermic coagulopathy in trauma: effect of varying levels of hypothermia on enzyme speed, platelet function, and fibrinolytic activity

BACKGROUND

The coagulopathy noted in hypothermic trauma patients has been variously theorized to be caused by either enzyme inhibition, platelet alteration, or fibrinolytic processes, but no study has examined the possibility that all three processes may simultaneously contribute to coagulopathy, but are perhaps triggered at different levels of hypothermia. The purpose of this study was to determine whether, at clinically common levels of hypothermia (33.0-36.9 degrees C), there are specific temperature levels at which coagulopathic alterations are seen in each of these processes.

METHODS

Of 232 consecutive adult trauma patients presenting to a Level I trauma center, 112 patients met the inclusion criteria of an Injury Severity Score of 9 or greater and time since injury of less than 2 hours. Of the included patients, 40 were normothermic and 72 were hypothermic (> or =37 degrees C, n = 40; 36.9-36 degrees C, n = 29; 35.9-35 degrees C, n = 20; 34.9-34 degrees C, n = 16; 33.9-33 degrees C, n = 7). Included patients were prospectively studied with thrombelastography adjusted to core body temperature. Additionally, PT, aPTT, platelets, CO2, hemoglobin, hematocrit, and Injury Severity Score were measured.

RESULTS

Analysis by multivariate analysis of variance of the relationship between coagulation and temperature demonstrated that in hypothermic trauma patients, 34 degrees C was the critical point at which enzyme activity slowed significantly (p < 0.0001), and at which significant alteration in platelet activity was seen (p < 0.001). Fibrinolysis was not significantly affected at any of the measured temperatures (p > 0.25).

CONCLUSIONS

Patients whose temperature was > or =34.0 degrees C actually demonstrated a significant hypercoagulability. Enzyme activity slowing and decreased platelet function individually contributed to hypothermic coagulopathy in patients with core temperatures below 34.0 degrees C. All the coagulation measures affected are part of the polymerization process of platelets and fibrin, and this process may be the mechanism by which the alteration in coagulation occurs.

Differences in mortality between elderly and younger adult trauma patients: geriatric status increases risk of delayed death

BACKGROUND

Elderly patients suffer higher mortality rates after trauma than younger patients. This increased mortality is attributable to age, preexisting disease, and complications as well as injury severity.

METHODS

Records from 5,139 adult patients from a Level I trauma center were retrospectively reviewed. Injury Severity Score (ISS), Revised Trauma Score (RTS), early mortality (<24 hours), and late mortality (>24 hours) were determined for elderly (> or =65 years) and younger (16-64 years) patients. Preexisting diseases and complications were identified by International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis coding.

RESULTS

Mortality in elderly patients was twice that in younger patients despite equivalent injury severity (p < 0.001), and elderly patients were more likely to suffer later death than younger patients (p < 0.005). The prevalence of preexisting disease was greater in the elderly, as was the incidence of complications. Using logistic regression, ISS, RTS, preexisting cardiovascular or liver disease, the development of cardiac, renal, or infectious complications, and geriatric status were all independently predictive of late mortality (p < 0.05).

CONCLUSION

Elderly trauma patients more frequently suffer late mortality than younger patients because of the combination of injury and increased preexisting disease and complications after injury. Aggressive treatment of the elderly trauma patient is warranted; however, in the face of significant preexisting disease or complications, survival is less likely. Predictive models of survival can be developed, taking into account preexisting disease and complications as well as admission parameters such as age, ISS, and RTS, and specific risk of mortality quantitated.

Relatively short diagnostic delays (<8 hours) produce morbidity and mortality in blunt small bowel injury: an analysis of time to operative intervention in 198 patients from a multicenter experience

OBJECTIVE

Blunt small bowel injury (SBI) is uncommon, and its timely diagnosis may be difficult. The impact of operative delays on morbidity and mortality has been unclear. The purpose of this study was to determine the relationship of diagnostic delays to morbidity and mortality in blunt SBI.

METHODS

Patients with blunt SBI with perforation were identified from the registries of eight trauma centers (1989-1997). Patients with duodenal injuries were excluded. Data were extracted by individual chart review. Patients were classified as multi-trauma (group 1) or near-isolated SBI (group 2 with Abbreviated Injury Scale score < 2 for other body areas). Time to operation and its impact on mortality and morbidity was determined for each patient.

RESULTS

A total of 198 patients met inclusion criteria: 66.2% were male, mean age was 35.2 years (range, 1-90 years) and mean Injury Severity Score was 16.7 (range, 9-47). 100 patients had multiple injuries (group 1). There were 21 deaths (10.6%) with 9 (4.5%) attributable to delay in operation for SBI. In patients with near-isolated SBI, the incidence of mortality increased with time to operative intervention (within 8 hours: 2%; 8-16 hours: 9.1%; 16-24 hours: 16.7%; greater than 24 hours: 30.8%, p = 0.009) as did the incidence of complications. Delays as short as 8 hours 5 minutes and 11 hours 15 minutes were associated with mortality attributable to SBI. The rates of delay in diagnosis were not significantly associated with age, gender, intoxication, transfer status, or presence of associated injuries.

CONCLUSION

Delays in the diagnosis of SBI are directly responsible for almost half the deaths in this series. Even relatively brief delays (as little as 8 hours) result in morbidity and mortality directly attributable to "missed" SBI. Further investigation into the prompt diagnosis of this injury is needed.

Detecting fake-good and fake-bad MMPI-2 profiles

This study examined the extent to which the validity scales of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) could identify subjects who were faking bad or faking good and differentiate between psychiatric patients and normal subjects who were faking bad. Subjects were 106 undergraduate college students and 50 psychiatric patients. Results indicate that the mean profiles and optimal cutoff scores resembled those previously reported for the original MMPI. Accurate identification of persons who were faking bad or faking good was achieved. It was possible to differentiate between the psychiatric patients and normal persons who were faking bad, but different cutoff scores were needed to differentiate between normals taking the test under standard instructions and those instructed to fake bad. Optimal cutoff scores were suggested.

Early experience with percutaneous tracheotomy

Early reports of a percutaneous dilatational technique for tracheotomy tube placement have been encouraging. This method uses a needle for placement into the trachea, a J-tipped guidewire, and progressively larger dilators to widen the stoma for insertion of a tracheotomy tube. A prospective study was undertaken to assess the efficacy of this percutaneous tracheotomy technique. Serious complications were encountered, including difficulty with dilatation, excessive bleeding, false passage of the tracheotomy tube, and death. Because of this unacceptable morbidity, the study was terminated after enrollment of only seven patients. Percutaneous tracheotomy is a dangerous procedure with potential for catastrophic complications. These complications were encountered by third- and fourth-year surgical residents performing the procedure under close supervision. If the puncture technique is further popularized and attempted by untrained physicians, these authors predict many disasters.

L-arginine administration normalizes pressure natriuresis in hypertensive Dahl rats

A blunted pressure-natriuretic response characterizes hypertension in the Dahl salt-sensitive rat. Long-term L-arginine administration prevents hypertension in these animals. To determine if long-term L-arginine corrects the pressure-natriuretic response, we gave salt-sensitive rats on an 8% sodium diet L-arginine or vehicle daily for 3 weeks. Identically treated salt-resistant rats served as controls. After 3 weeks, acute pressure-natriuresis curves were determined. To control for hypertension-induced renal damage, we also examined pressure natriuresis in salt-sensitive rats after short-term L-arginine. Baseline mean arterial pressure was 158 +/- 3 mm Hg in vehicle-treated salt-sensitive rats and 127 +/- 3 mm Hg in chronically L-arginine-treated salt-sensitive rats. During alterations in perfusion pressure, renal blood flow was autoregulated in all groups. Glomerular filtration rate was autoregulated in salt-resistant rats and L-arginine-treated salt-sensitive rats but fell with decreasing pressure in vehicle-treated salt-sensitive rats. Sodium excretion was greater (P < .05) in L-arginine-treated than in vehicle-treated salt-sensitive rats and did not differ from salt-resistant rats at 100, 125, and 158 mm Hg. The slope of the pressure-natriuresis relation was greater (P < .05) in chronically L-arginine-treated than in vehicle-treated salt-sensitive rats. L-Arginine had no effect on natriuresis in salt-resistant rats. Thus, long-term L-arginine administration normalizes pressure-natriuretic responses in salt-sensitive rats. The effect is not due to the prevention of renal damage and is specific to the salt-sensitive strain.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a post-Columbian introduction of human T-cell lymphotropic virus [type I] [corrected] in Latin America

To investigate the origin and dissemination of human T-cell lymphotropic virus type I in Latin America, we performed phylogenetic analysis on the LTR and env sequences of 13 HTLV-I isolates from Peruvians of four different ethnic groups: blacks and some mulattos of African origin; Quechuas of Inca origin; Nikkei of Japanese descendance; and Mestizos, a mixed population of white and Indian origin. All Peruvian samples could be situated within the cosmopolitan subtype HTLV-Ia, yet one sample showed an indeterminate Western blot pattern, lacking reactivity towards the HTLV-I type specific MTA1 peptide. Within the LTR, we could confirm the previously reported subdivision into four subgroups--one big transcontinental clade A, a Japanese clade B, a West African/Caribbean clade C and a North African clade D--and we identified a new separate subgroup E of black Peruvian strains. The clustering of the Peruvian samples seemed to depend on the ethnic origin of the host. The largest heterogeneity was observed in the black Peruvian samples. The mitochondrial DNA type of one of these black Peruvian strains of subgroup E was identical to that of West African source populations of the slave trade. Both findings support the idea of multiple post-Columbian introductions of African HTLV-Ia strains into the black Latin American population. Additionally, a tight cluster of Nikkei and Japanese samples implied a separate and rather recent transmission of a Japanese lineage of HTLV-I into Peru. A well-supported cluster of Latin American strains (including Peruvian Quechuas and Colombian Amerindians) could be situated within the transcontinental group. Molecular clock analysis of the Latin American and Japanese clade resulted in an equal evolutionary rate for those strains. Along with the anthropologically documented peopling of the Americas, the analysis was more in favour of a recent (400 to 100 years ago) introduction of HTLV-Ia into the American continent rather than a Palaeolithic introduction.

The utility of traditional prehospital interventions in maintaining thermostasis

OBJECTIVE

Hypothermia can have a negative effect on the metabolic and hemostatic functions of patients with traumatic injuries. Multiple methods of rewarming are currently used in the prehospital arena, but little objective evidence for their effectiveness in this setting exists. The purpose of this study was to assess the relative effectiveness of traditional prehospital measures in maintaining thermostasis in trauma patients.

METHODS

Participating helicopter and ground ambulance ALS units were prospectively randomized to provide either routine care only (passive or no warming) or routine care (passive warming) in conjunction with active warming (either reflective blankets, hot pack rewarming, or warmed IV fluids). A total of 174 trauma code patients, aged >14 years, who met inclusion criteria were prospectively enrolled by prehospital providers. Patients who received a non-assigned intervention or who had incomplete temperature data were dropped from the analysis. A total of 134 patients were included in the final analysis.

RESULTS

Patients who received hot pack rewarming showed a mean increase in body temperature during transport (+1.36 degrees F/0.74 degrees C), while all other groups (no intervention, passive rewarming, reflective blankets, warmed IV fluids, warmed IV fluid plus reflective blanket) showed a mean decrease in temperature during transport [-0.34 to -0.61 degrees F (-0.2 to -0.4 degrees C); p<0.01]. In addition, the hot pack group was consistent, with every patient who received hot pack warming showing an increase in body temperature during transport, while in all other groups there were patients who had both increases and decreases in temperature. The intervention groups did not differ significantly on exposure to precipitation, transport unit temperature, total prehospital time, initial vital signs, amount of fluid administered, Injury Severity Score, or Glasgow Coma Score.

CONCLUSIONS

Most traditional methods of maintaining trauma patient temperature during prehospital transport appear to be inadequate. Aggressive use of hot packs, a simple, inexpensive intervention to maintain thermostasis, deserves further study as a potential basic intervention for trauma patients.

Review article: is clinical remission the optimum therapeutic goal in the treatment of Crohn's disease?

Currently, the therapeutic end-point in the treatment of Crohn's disease is the remission of symptoms, but recent data confirm that mucosal inflammation may continue in the absence of symptoms. Furthermore, emerging evidence indicates that such subtle, sub-clinical mucosal inflammation leads to clinical relapse. The assessment of mucosal inflammation has become easier with the availability of faecal calprotectin assay. Current anti-inflammatory therapy often leaves low-grade mucosal inflammation untreated, and therefore recurrent relapses occur. We need to investigate whether the therapeutic end-point of anti-inflammatory medications needs to be more rigorous and to aim at complete mucosal healing, confirmed by the normalization of mucosal inflammatory markers such as faecal calprotectin concentrations. Immunosuppressive therapy with azathioprine/ 6-mercaptopurine currently offers the best mucosal healing treatment with reduction of relapses, but newer biological agents might offer less toxic therapy. Clinical trials to test the feasibility and efficacy of such a paradigm shift in the medical management of Crohn's disease are now warranted.

Community-based prevalence profile of arboviral, rickettsial, and Hantaan-like viral antibody in the Nile River Delta of Egypt

To determine the current prevalence of antibody to arboviruses, rickettsiae, and hantaan-like viruses, a survey was carried out in the Nile River Valley of Egypt, one of the principal foci of the 1977-1978 Rift Valley fever (RVF) outbreak. Blood specimens were obtained from 915 persons representing 190 study households. Enzyme immunoassay testing showed that the overall prevalence of IgG antibody was 4% to sand fly fever Sicilian (SFS), 2% to sandfly fever Naples (SFN), 15% to RVF, 20% to West Nile, and 4% to Hantaan (HTN) viruses. Antibody was demonstrated among 32% of the same study subjects to Coxiella burnetii, 58% to Rickettsia typhi, and 32% to R. conorii. The prevalence of agent-specific antibody tended to increase with age. Particularly notable was the low prevalence of RVF infection in children born after the height of the RVF outbreak. No detectable antibodies were found in the population less than seven years of age and in only 3% of those 7-12 years old. In contrast, 26% of the study population 13-19 years old, who were young children and infants at the time of the outbreak, were found to have RVF antibodies, suggesting that the level of intensity associated with transmission decreased considerably following the documented 1977-1978 outbreak. Geometric mean titers (GMT) ranged from 139 for C. burnetii to 1,305 for RVF, and did not vary significantly by age, except for high titers for RVF in the 20-49-year-old age group. A significant upward trend in GMT was also noted when antibody was detected in the specimen for more than one phlebovirus.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology of Norwalk virus during an outbreak of acute gastroenteritis aboard a US aircraft carrier

A large outbreak of acute gastroenteritis occurred over a 5-week period aboard an aircraft carrier. The estimated cumulative attack rate was 13% among the 4,500-man crew. Eight percent of the crew sought medical attention, nearly all of whom missed 1 day or more of work. The risk of developing illness was 2 to 3 times greater for individuals living in more crowded sleeping quarters (> 50 persons per compartment). Occurrence of gastroenteritis was associated with a fourfold or more rise in Norwalk virus antibody levels, as measured by an enzyme-linked immunoassay utilizing a baculovirus expressed recombinant antigen. In addition, 27 nm Norwalk virus-like particles were visualized in two of six stools examined by immune electron microscopy. The presence of a low (< 1:50) or a high (> or = 1:6,400) pre-illness antibody level was associated with a lower incidence of illness. This investigation indicates that Norwalk virus can adversely impact operations of a military vessel and that crowding is a major risk factor in transmission.

A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan

A waterborne outbreak of leptospirosis occurred among US military personnel during September 1987, on the island of Okinawa, Japan. Micro-agglutination titres for leptospiral antigen of greater than or equal to 200 were detected in hospitalized adult males averaging 22.5 years of age with symptoms compatible with leptospirosis. Epidemiological findings revealed two case clusters distinguished by time and place of exposure. The overall attack rates among recreational swimmers and combat skills training participants were 467/1000 (7/15) and 183/1000 (15/82), respectively. Swallowing of water differentiated individuals with laboratory-confirmed infection from those with no infection, while water immersion alone did not appear to result in leptospiral infection. Additionally, subnormal rainfall may have contributed to the risk of exposure associated with this outbreak.

Prevalence of human retroviral infection in Quillabamba and Cuzco, Peru: a new endemic area for human T cell lymphotropic virus type 1

An epidemiologic study was conducted to determine the prevalence of retroviral infections among people of Qucchua origin in Cuzco and Quillabamba, Peru. The study volunteers included individuals at low and at high risk for retroviral infections. Each volunteer was interviewed to obtain clinical and epidemiologic data, and to identify risk behaviors for infection. The serum was tested for human immunodeficiency virus type 1 (HIV-1) and human T cell lymphotropic virus types 1/2 (HTLV-1/2) by standard enzyme-linked immunosorbent and Western blot assays. Among a total of 370 volunteers enrolled in the study, 276 were women and 94 were men whose ages ranged between 15 and 49 years. Infection with HTLV-1 was demonstrated in 5.1% (19 of 370), and one of these, a homosexual, was also positive for HIV-1; none had HTLV-2. Overall, the rate of HTLV-1 infection was 5.3% (5 of 94) for males and 5% (14 of 276) for females. Among the low risk group of 211 healthy pregnant women, five (2.3%) were positive for HTLV-1. The rate of HTLV-1 infection in this group was significantly correlated with a history of dental surgery, as well as other surgical procedures, and a history of jaundice. Among the volunteers who practiced risk behavior(s) for retroviral infections, the positive rates for HTLV-1 were 13.7% (7 of 51) for female sex workers, 6.2% (3 of 48) for homosexuals and/or bisexuals, 8.5% (4 of 47) for patients with sexually transmitted diseases (STDs), and 0.0% (0 of 13) for promiscuous heterosexual males. In female sex workers. HTLV-1 infection was found to be significantly associated with age, a history of STDs or genital ulcers, sexual intercourse during menses, and vaginal douching (P < 0.05). A low prevalence of HIV-1 infection indicates that the virus has not yet spread significantly in these areas.

Windows 99: a source of suburban pediatric trauma

BACKGROUND

Falls from windows in urban areas cause a significant number of pediatric injuries. Window falls have not been well described in the nonurban setting. We describe the epidemiology of window falls from residential homes among pediatric patients at a suburban Level I trauma center.

METHODS

A review of patients admitted from January 1991 through November 1999 to a center serving a rapidly growing suburban area was performed.

RESULTS

A total of 2,322 children, ages 0-14 years, were admitted during the study period. Falls comprised 41% of these admissions, and 11% of falls were from windows, greater than twice the national average. More than 39% of children who fell from windows were admitted directly to the intensive care unit. Overall mortality rate was 4%. Ages 0 to 4 years comprised the largest percentage (83%), and all children who died were in this age group. Children < or = 4 years were more likely to have an Abbreviated Injury Score > or = 2 (head injury) than those ages 10 to 14 years (p = 0.032). More than 31% of all children injured in window falls seen at the study institution between 1991 and 1999 were admitted in the last 2 years.

CONCLUSION

Pediatric falls from windows in this suburban area appear to be increasing, with an incidence greater than the national average. Children at greatest risk are less than 4 years old. Further research in injury prevention at the national level aimed at suburban areas may be warranted.

Substrate recognition and selectivity in the type IC DNA modification methylase M.EcoR124I

The type I DNA modification methylase M.EcoR124I binds sequence specifically to DNA and protects a 25bp fragment containing its cognate recognition sequence from digestion by exonuclease III. Using modified synthetic oligonucleotide duplexes we have investigated the catalytic properties of the methylase, and have established that a specific adenine on each strand of DNA is the site of methylation. We show that the rate of methylation of each adenine is increased at least 100 fold by prior methylation at the other site. However, this is accompanied by a significant decrease in the affinity of the methylase for these substrates according to competitive gel retardation assays. In contrast, methylation of an adenine in the recognition site which is not a target for the enzyme results in only a small decrease in both DNA binding affinity and rate of methylation by the enzyme.

DNA-binding induces a major structural transition in a type I methyltransferase

The type IC DNA methyltransferase M.EcoR124I is a complex multisubunit enzyme that recognizes the non-palindromic DNA sequence GAAN6RTCG. Small angle X-ray scattering has been used to investigate the solution structure of the methyltransferase and of complexes of the enzyme with unmethylated and hemimethylated 30 bp DNA duplexes containing the specific recognition sequence. A major change in the quaternary structure of the enzyme is observed following DNA binding, based on a decrease in the radius of gyration from 56 to 40 A and a reduction in the maximum dimension of the enzyme from 180 to 112 A. The structural transition observed is independent of the methylation state of the DNA. CD shows that there is no change in the secondary structure of the protein subunits when DNA is bound. In contrast, there is a large increase in the CD signal arising from the DNA, suggesting considerable structural distortion which may allow access to the bases targeted for methylation. We propose that DNA binding induces a large rotation of the two HsdM subunits towards the DNA, mediated by hinge bending domains in the specificity subunit HsdS.

Dietary arginine alters time of symptom onset in Huntington's disease transgenic mice

Recent neuroimaging studies reported complex changes in cerebral blood flow (CBF) in early-staged Huntington's disease (HD) patients. Deckel and co-workers [Deckel and Duffy, Brain Res. (in press); Deckel and Cohen, Prog. Neuro-Psychopharmacol. Biol. Psychiatry 24 (2000) 193; Deckel et al., Neurology 51 (1998) 1576; Deckel et al., J. Nucl. Med. 41 (2000) 773] suggested that these findings might be accounted for, in part, by alterations in cerebral nitric oxide (NO) and its byproduct, peroxynitrite. The current experiment tested this hypothesis by altering NO levels via manipulations of dietary L-arginine (ARG), the dietary precursor of NO, in mice transgenic for HD. Seventy-one mice were assigned at 12 weeks of age to one of three isocaloric diets that varied in their content of ARG. These diets included: (a) 0% ARG, (b) 1.2% ARG (i.e. typical mouse chow), or (c) 5% ARG. The 5% ARG diets in HD mice accelerated the time of onset of body weight loss (P<0.05) and motor impairments (P<0.05), and increased resting CBF in HD relative to control (P<0.05). Conversely, the 0% ARG diet demonstrated no loss of body weight and had no changes in CBF relative to controls. However, the 0% ARG HD group continued to show significant deficits on motor testing (P<0. 05). The 1.2% ARG HD group showed reduced body weight loss, better motor functioning, and fewer changes in CBF compared to the 5% ARG HD group. Immunocytochemistry analysis found greater deposition of nitrotyrosine in the cortex, and vasculature, of HD+ mice, 5% and 1. 2%>0% arginine diets. When collapsed across all conditions, CBF inversely correlated (P<0.05) both with the body weight and motor changes suggesting that changes in CBF are associated with behavioral decline in HD mice. Collectively, these findings indicate that dietary consumption of the NO precursor ARG has a measurable, but complex, effect on symptom progression in HD transgenic mice, and implicates NO in the pathophysiology of HD.

Management of gastrointestinal haemorrhage

A variety of endoscopic haemostatic techniques have enabled major advances in the management of not only bleeding peptic ulcers and bleeding varices, but also in a variety of bleeding lesions in the small intestine and in the colon. Indeed, the development and widespread implementation of endoscopic haemostasis has been one of the most important developments in clinical gastroenterology in the past two decades. An increasingly ageing cohort of patients with multiple co-morbidity are being treated and therefore improving the outcome of gastrointestinal bleeding continues to pose major challenges.

Defibrillation by basic emergency medical technicians: effect on survival

Several studies have examined the effect of early defibrillation by basic EMTs on patient survival. Although the studies have a common theme of early basic EMT defibrillation, they are diverse in locations, devices, control groups, caregivers, and protocols. They provide a confusing array of information that is difficult to review, synthesize, and interpret. Metaanalysis allows data pooling of these primary studies to combine results and statistically compare the observed variation in study outcomes. The purpose of this metaanalysis was to examine the published studies of early basic EMT defibrillation to learn whether this treatment has an effect on survival of out-of-hospital cardiac arrest. Analysis of the 10 studies that met inclusion criteria showed that despite variations in design, the overall effect size for all the studies was .092, indicating a 9.2% increase in survival over what would have been expected had the EMT-Ds not intervened.

Effect of a bicycle safety program and free bicycle helmet distribution on the use of bicycle helmets by elementary school children

OBJECTIVE

Each year in the United States, 300,000 children are treated in emergency departments for bicycle injuries; one third have head injuries. The purpose of this study was to determine the effectiveness of educational interventions and free helmet distribution in increasing the use of helmets by elementary school children.

METHODS

Self-report questionnaires on the use of bicycle helmets were used for students at two elementary schools (n = 1610). Testing was done both before and after the administration of a bicycle safety program and the distribution of free helmets. Pretest and posttest answers were then compared for changes in helmet use.

RESULTS

Helmet usage increased significantly after the bicycle safety program, from 38% to 46% overall (p < 0.005). Children who were given free helmets were significantly more likely to wear their helmets (61.4%) than children who already owned helmets (43.4%) (p > 0.016). Children who attended the school in which free helmets were distributed showed a significant increase in helmet use (p < 0.01), whereas those at the school that had a safety program alone did not show a significant increase (p > 0.17).

DISCUSSION

The results of this study suggest that bicycle safety programs and free helmet distribution may increase the consistent use of helmets in elementary school children.