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Biomedical subjects

R E Jackson

Publications and source records attributed to R E Jackson.

At least 19 recordsLinked to original sources

Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in eastern North Carolina.

To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).

Animals↗

Comparative production of Helicoverpa zea (Lepidoptera: Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays.

Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.

Animals↗

Cardiac arrest in private locations: different strategies are needed to improve outcome.

BACKGROUND: A tremendous amount of public resources are focused on improving cardiac arrest (OHCA) survival in public places, yet most OHCAs occur in private residences. METHODS AND RESULTS: A prospective, observational study of patients transported to seven urban and suburban hospitals and the individuals who called 911 at the time of a cardiac arrest (bystander) was performed. Bystanders (N=543) were interviewed via telephone beginning 2 weeks after the incident to obtain data regarding patient and bystander demographics, including cardiopulmonary resuscitation (CPR) training. Of all arrests 80.2% were in homes. Patients who arrested in public places were significantly younger (63.2 vs. 67.2, P<0.02), more often had an initial rhythm of VF (63.0 vs. 37.7%, P<0.001), were seen or heard to have collapsed by a bystander (74.8 vs. 48.1%, P<0.001), received bystander CPR (60.2 vs. 28.6%, P<0.001), and survived to DC (17.5 vs. 5.5%, P<0.001). Patients who arrested at home were older and had an older bystander (55.4 vs. 41.3, P<0.001). The bystander was less likely to be CPR trained (65.0 vs. 47.4%, P<0.001), less likely to be trained within the last 5 years (49.2 vs. 17.9, P<0.001), and less likely to perform CPR if trained (64.2 vs. 30.0%, P<0.001). Collapse to shock intervals for public versus home VF patients were not different. CONCLUSIONS: Many important characteristics of cardiac arrest patients and the bystander differ in public versus private locations. Fundamentally different strategies are needed to improve survival from these events.

Cardiopulmonary Resuscitation↗

Performance assessment of NAPL remediation in heterogeneous alluvium.

Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been conducted at many different sites to measure nonaqueous phase liquid (NAPL) saturations in the subsurface. While the main goal of these PITTs was to estimate the NAPL volume in the subsurface, some were specifically conducted to assess the performance of remedial actions involving NAPL removal. In this paper, we present a quantitative approach to assess the performance of remedial actions to recover NAPL that can be used to assess any NAPL removal technology. It combines the use of PITTs (to estimate the NAPL volume in the swept pore volume between injection and extraction wells of a test area) with the use of several cores to determine the vertical NAPL distribution in the subsurface. We illustrate the effectiveness of such an approach by assessing the performance of a surfactant/foam flood conducted at Hill Air Force Base, UT, to remove a TCE-rich NAPL from alluvium with permeability contrasts as high as one order of magnitude. In addition, we compare the NAPL volumes determined by the PITTs with volumes estimated through geostatistical interpolation of aquifer sediment core data collected with a vertical frequency of 5-10 cm and a lateral borehole spacing of 0.15 m. We demonstrate the use of several innovations including the explicit estimation of not only the errors associated with NAPL volumes and saturations derived from PITTs but also the heterogeneity of the aquifer sediments based upon permeability estimates. Most importantly, we demonstrate the reliability of the

Environmental Monitoring↗

A randomized trial of the effects of early cardiac serum marker availability on reperfusion therapy in patients with acute myocardial infarction: the serial markers, acute myocardial infarction and rapid treatment trial (SMARTT).

OBJECTIVES: The purpose of this study was to assess whether the immediate availability of serum markers would increase the appropriate use of thrombolytic therapy. BACKGROUND: Serum markers such as myoglobin and creatine kinase, MB fraction (CK-MB) are effective in detecting acute myocardial infarction (AMI) in the emergency setting. Appropriate candidates for thrombolytic therapy are not always identified in the emergency department (ED), as 20% to 30% of eligible patients go untreated, representing 10% to 15% of all patients with AMI. Patients presenting with chest pain consistent with acute coronary syndrome were evaluated in the EDs of 12 hospitals throughout North America. METHODS: In this randomized, controlled clinical trial, physicians received either the immediate myoglobin/CK-MB results at 0 and 1 h after enrollment (stat) or conventional reporting of myoglobin/CK-MB 3 h or more after hospital admission (control). The primary end point was the comparison of the proportion of patients within the stat group versus control group who received appropriate thrombolytic therapy. Secondary end points included the emergent use of any reperfusion treatment in both groups, initial hospital disposition of patients (coronary care unit, monitor or nonmonitor beds) and the proportion of patients appropriately discharged from the ED. RESULTS: Of 6,352 patients enrolled, 814 (12.8%) were diagnosed as having AMI. For patients having AMI, there were no statistically significant differences in the proportion of patients treated with thrombolytic therapy between the stat and control groups (15.1% vs. 17.1%, p = 0.45). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were still no significant differences between the groups. Also, there was no difference in the hospital placement of patients in critical care and non- critical care beds. The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, p = 0.023). CONCLUSIONS: The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, and it slightly increased the number of patients admitted to the hospital who had no evidence of acute myocardial necrosis.

Biomarkers↗

Behavioural and physiological responses of sheep to 16 h transport and a novel environment post-transport.

The effect of a novel lairage environment on the ability of sheep to recover from 16 h of transport was investigated. Sheep were transported from grass paddocks to either novel outside paddocks or inside pens, and housed groups were transported to either familiar or novel inside pens. During transport, sheep from outside paddocks lay down less than those from inside pens. In sheep transported to inside pens, those from outside paddocks spent more time lying and spent less time eating; hay and water intakes during the first 12 h post-transport were lower than those previously kept inside. There was no obvious effect of a novel environment post-transport on blood biochemistry, suggesting that the lower post-transport feed and water intakes in a novel environment did not have a significant effect on the ability of the sheep to recover from the feed and water deprivation associated with transport.

Animals↗

Effects of acute pain reduction methods on the chronic inflammatory lesions and behaviour of lambs castrated and tail docked with rubber rings at less than two days of age.

Lesions were produced by castration and tail docking of two-day-old Dorset-cross lambs with elastrator rings with (RRla) and without (RR) local anaesthetic or after destruction of the innervation by crushing close to the ring (Brr). The lesions were monitored twice weekly for six weeks and the behaviour of handled controls (H), RR and RRla lambs was recorded for two 3 h periods 10, 20, 31 and 41 days after treatment. There was no significant effect of castration and tail docking, with or without pain reduction methods, on daily liveweight gain. In the Brr lambs, the dead tails were cast 10 days earlier than from RR and RRla lambs. The time taken for the scrotal lesion to reach maximum severity was halved in Brr and RRla lambs, although the maximum severity of the lesion was unaffected by the methods of pain reduction. During the four 6 h behavioural observation periods, RR lambs showed a significant increase in the mean (+/- sd) frequency of foot stamping (RR13 +/- 13; H2 +/- 2.5), tail wagging (61 +/- 26; 15 +/- 6), head turning to the scrotum and inside hind-leg (12 +/- 10; 1 +/- 1). Less abnormal behaviour was found after RRla than after RR treatment. This unexpected finding may be evidence of long-lasting increases in pain sensitivity after an episode of intense acute pain in young animals.

Animal Welfare↗

Prospective evaluation of two-dimensional transthoracic echocardiography in emergency department patients with suspected pulmonary embolism.

OBJECTIVE: To prospectively examine the diagnostic accuracy of two-dimensional transthoracic echocardiography (2-D echo) in emergency department (ED) patients being evaluated for acute pulmonary embolism (PE). METHODS: This was a 14-month prospective observational trial of a convenience sample of ED patients undergoing evaluation for suspected PE at a suburban teaching hospital. The 2-D echo was defined as positive if any two of the following were noted: right ventricular dilation, abnormal septal motion, loss of right ventricular contractility, elevated pulmonary artery or right ventricular pressures, moderate to severe tricuspid regurgitation, or visualization of a clot seen in the right ventricle or pulmonary artery. The patient was considered to have a PE if one of the following was positive: a pulmonary angiogram, contrast helical computed tomography, a magnetic resonance angiogram, a high-probability ventilation/perfusion (V/Q) scan without contradictory evidence, or an intermediate-probability V/Q scan with ultrasonic evidence of deep venous thrombosis. RESULTS: Of 225 cases identified, 39 met the defined criteria for PE (17%). A 2-D echo was performed on 124 patients (55%), of whom 27 (22%) had PE. In 20 patients the 2-D echo had at least two indicators of right ventricular strain; however, only 11 of these patients had confirmed pulmonary embolus. The 2-D echo had a sensitivity of 0.41 (95% CI = 0.32 to 0.49) and a specificity of 0.91 (95% CI = 0.86 to 0.96). The likelihood ratio positive was a moderately strong 4.4, with a weak likelihood ratio negative of 0.6. CONCLUSIONS: Bedside 2-D echo is not a sensitive test for the diagnosis of PE in ED patients. Positive findings moderately increase the suspicion for PE but are not diagnostic.

Adult↗

Does advanced age matter in outcomes after out-of-hospital cardiac arrest in community-dwelling adults?

OBJECTIVE: To assess whether advanced age is an independent predictor of survival to hospital discharge in community-dwelling adult patients who sustained an out-of-hospital cardiac arrest in a suburban county. METHODS: A prospective cohort study was conducted in a suburban county emergency medical services system of community-dwelling adults who had an arrest from a presumed cardiac cause and who received out-of-hospital resuscitative efforts from July 1989 to December 1993. The cohorts were defined by grouping ages by decade: 19-39, 40-49, 50-59, 60-69, 70-79, and 80 or more. The variables measured included age, gender, witnessed arrest, response intervals, location of arrest, documented bystander cardiopulmonary resuscitation, and initial rhythms. The primary outcome was survival to hospital discharge. Results are reported using analysis of variance, chi square, and adjusted odds ratios from a logistic regression model. Age group 50-59 served as the reference group for the regression model. RESULTS: Of the 2,608 total presumed cardiac arrests, the overall survival rate to hospital discharge was 7.25%. Patients in age groups 40-49 and 50-59 experienced the best rate of successful resuscitation (10%). Each subsequent decade had a steady decline in successful outcome: 8.1% for ages 60-69; 7.1% for ages 70-79; and 3.3% for age 80+. In a post-hoc analysis, further separation of the older age group revealed a successful outcome in 3.9% of patients ages 80-89 and 1% in patients 90 and older. Patients aged 80 years or more were more likely to arrest at home, were more likely to have an initial bradyasystolic rhythm, yet had a similar rate of resuscitation to hospital admission. In the regression model, age 80 or older was associated with a significantly worse survival to hospital discharge (OR = 0.4, 95% CI = 0.20 to 0.82). CONCLUSIONS: There was a twofold decrease in survival following out-of-hospital cardiac arrest to discharge in patients aged 80 or more when compared with the reference group in this suburban county setting. However, resuscitation for community-dwelling elders aged 65-89 is not futile. These data support that out-of-hospital resuscitation of elders up to age 90 years is not associated with a universal dismal outcome.

Adult↗

Utility of lower extremity venous ultrasound scanning in the diagnosis and exclusion of pulmonary embolism in outpatients.

STUDY OBJECTIVE: Emergency physicians frequently rely on normal findings from a lower extremity venous ultrasound examination as a method to decrease the probability of pulmonary embolism (PE) in outpatients with a nondiagnostic ventilation-perfusion lung scan (V/Q scan). The objective of this study was to evaluate the diagnostic utility of bilateral lower extremity venous ultrasound scanning in the diagnosis of PE in emergency department patients with a low-, moderate-, or indeterminate-probability (nondiagnostic) V/Q scan. METHODS: This prospective, 2-center, descriptive study was conducted at the EDs of 2 large teaching hospitals. From an initial cohort of 570 nonreferred outpatients, a convenience sample of 156 patients who had both a nondiagnostic V/Q scan and a lower extremity venous ultrasound scan performed was selected as the study population. The sensitivity and specificity for a single lower extremity venous ultrasound scan and the posttest probability of PE were determined for the study population. RESULTS: In the study population, the best-case sensitivity of the lower extremity venous ultrasound scan for PE was 54% (95% confidence interval [CI] 37% to 71%) and the specificity was 98% (95% CI 94% to 100%). The likelihood ratio of a positive test result was 27. The likelihood ratio of a negative test result was 0.49, yielding a lowest possible posttest probability of PE of 12% (95% CI 6% to 17%). CONCLUSION: This study demonstrates that the combination of a nondiagnostic (low, moderate, or indeterminate) V/Q scan plus a single negative result from lower extremity venous ultrasound examination, even in a best-case scenario, does not exclude the diagnosis of PE.

Adult↗

Production of virus-specific antisera using synthetic peptides corresponding to sequences in the yellow fever E protein: brief report.

Synthetic peptides have gained widespread acceptance for use in epitope mapping and as immunogens for monoclonal antibody and polyclonal serum production. Putative antigenic peptides homologous to regions in the primary sequence of the envelope protein (E) of yellow fever virus (YF17D) were synthesized and evaluated for their ability to produce polyclonal antisera specific for the parent protein and for their reactivity with a panel of E-specific mAb. Antipeptide sera were reacted with native virus in ELISA, Western blot, neutralization, hemagglutination-inhibition, and immunofluorescence tests. Reactive sera were in most cases specific for the original peptide. However, despite the diversity of peptide selection processes, we were unable to identify any antipeptide serum that reacted specifically with authentic YF E protein.

Amino Acid Sequence↗

Who gets bystander cardiopulmonary resuscitation in a witnessed arrest?

OBJECTIVE: To identify characteristics associated with provision of bystander CPR in witnessed out-of-hospital cardiac arrest cases. METHODS: An observational, prospective, cohort study was performed using cardiac arrest cases as identified by emergency medical services (EMS) agencies in Oakland County. MI, from July 1, 1989, to December 31, 1993. All patients who sustained a witnessed arrest prior to arrival of EMS personnel were reviewed. RESULTS: Of the 927 patients meeting entry criteria, the 229 patients receiving bystander CPR were younger: 60.9 +/- 14.7 vs 67.9 +/- 14.7 years (p < 0.01). Most (76.6%) cardiac arrests occurred in the home. In a multivariate logistic model, only the location of arrest outside the home was a significant predictor of receiving bystander CPR [odds ratio (OR) 3.8; 99% CI 2.5, 5.9]. Arrests outside the home were associated with significantly improved outcome, with 18.2% of out-of-home and 8.2% of in-home victims discharged from the hospital alive (OR 2.5; 99% CI 1.4, 4.4). CONCLUSION: Patients who have had witnessed cardiac arrests outside the home are nearly 4 times more likely to receive bystander CPR, and are twice as likely to survive. This observation emphasizes the need for CPR training of family members in the authors' locale. This phenomenon may also represent a significant confounder in studies of out-of-hospital cardiac arrest and resuscitation.

Age Factors↗

Effect of a patient's sex on the timing of thrombolytic therapy.

STUDY OBJECTIVE: We sought to determine whether a patient's sex independently influences the interval from emergency department arrival to the initiation of thrombolytic therapy in acute myocardial infarction (AMI). METHODS: We conducted a retrospective cohort study in two suburban EDs, one at a 929-bed tertiary care teaching hospital and the other at a 189-bed community hospital. Only patients found to be having an ST-segment-elevated AMI on their first ECG who were treated with a thrombolytic agent in the ED were eligible. We excluded patients who arrived at the ED after cardiac arrest or with a known AMI. We used as the main outcome measure the interval from ED arrival to initiation of thrombolytic therapy. Secondary outcome variables included time elapsed before ECG, interval between ECG and treatment, and 1-year mortality. RESULTS: Entry criteria were satisfied by 328 patients. The 88 women experienced a mean 23-minute delay to treatment initiation compared with men (P < .01). This observation is not accounted for by age, race, time of day, medical history, sex of the physician, type of thrombolytic agent, hospital, or triage category. The longest delays were found in women treated by female physicians, although female physicians also waited longer than male physicians to administer thrombolytic therapy to men. The mean time elapsed before the first ECG was also 6 minutes longer for women (P < .01) Women had an increased 1-year mortality rate that was fully explained by their advanced age at the time of AMI. CONCLUSION: We infer that a patient's sex may play a significant role in the observed delay in treatment for women. Our data, coupled with previously published work, strongly suggest a systematic negative effect for women in their interaction with the health care system during AMI. We suggest that variables other than systems issues affect the time elapsed before thrombolytic therapy.

Aged↗

Natural cytokine antagonists and endogenous antiendotoxin core antibodies in sepsis syndrome. The Sepsis Intervention Group.

OBJECTIVE: To assess the value of measuring circulating concentrations of mediators (endotoxin, tumor necrosis factor-alpha [TNF-alpha], interleukin-1 beta [IL-1 beta], and interleukin-6[IL-6]) and their endogenous antagonists (antiendotoxin core antibody [EndoCAb], interleukin-1 receptor antagonist [IL-1ra], and soluble TNF receptors [sTNF-R]) in predicting mortality and organ failure in sepsis syndrome. DESIGN: Cohort study with a follow-up period of 30 days. SETTING: Intensive therapy units of five tertiary referral centers in Scotland. SUBJECTS: A total of 146 intensive therapy unit patients with sepsis syndrome underwent repeated sampling during a 10-day period following admission to an intensive therapy unit. MAIN OUTCOME MEASURES: Circulating concentrations of mediators and antagonists were compared in survivors and nonsurvivors. RESULTS: Median Acute Physiology and Chronic Health Evaluation II score was 23 (range, 8 to 40). Mortality at 30 days was 49%. On entry to the study, circulating endotoxin was detected in 66% of patients, TNF-alpha in 14%, and IL-1 beta in 29%. Levels did not predict mortality or organ failure. Patients with IL-6 concentrations in excess of 3000 pg/mL had an increased mortality rate (64% vs 40%, P = .02). The incidence of IgG EndoCAb depletion on entry to the study was 26% in nonsurvivors and 10% in survivors (P = .02). Initial concentrations of both type I and type II sTNF-R were significantly higher in nonsurvivors (P < .01). Initial circulating IL-1ra concentrations were not of value in predicting mortality. Cytokine antagonists were present in concentrations 30- to 100,000-fold greater than their corresponding cytokine. CONCLUSION: The observed high circulating levels of the cytokine antagonists IL-1ra and sTNF-R and the relatively small proportion of patients developing EndoCAb depletion may contribute to the limitations of therapies that aim to augment natural defenses against endotoxin or the proinflammatory cytokines.

APACHE↗

Clinical decision rules discriminate between fractures and nonfractures in acute isolated knee trauma.

STUDY OBJECTIVE: To develop criteria that optimize clinical decisionmaking in the use of radiography after isolated knee trauma in adults. DESIGN: A prospective survey of emergency department patients over a 7-month period. Standardized data forms were completed by emergency physicians, residents, and certified physician assistants. SETTING: A large suburban community teaching hospital. PARTICIPANTS: Two hundred forty-two patients older than 17 years with isolated knee injuries sustained less than 24 hours previously. RESULTS: We constructed a clinical decision model, calculating sensitivity, specificity, and odds ratios. Twenty-eight patients (11.6%) had fractures, with the patella the most commonly fractured osseous structure. Patients able to walk without limping had not experienced a fracture, nor had patients with twist injuries without effusion. Sensitivity of this model for detecting fracture was 1.0 (99% confidence interval, .97 to 1.0), and specificity was .337 (99% confidence interval, .26 to .42). CONCLUSION: Clinical decision rules are effective in detecting knee fractures with 100% sensitivity and with sufficient specificity to eliminate 29% of knee radiographs in the ED. These findings require prospective validation.

Adolescent↗

Bystander CPR, ventricular fibrillation, and survival in witnessed, unmonitored out-of-hospital cardiac arrest.

STUDY OBJECTIVE: To assess whether bystander CPR (BCPR) on collapse affects initial rhythm and outcome in patients with witnessed, unmonitored out-of-hospital cardiac arrest (OHCA). DESIGN: Prospective cohort study. Student's t test, the chi 2 test, and logistic regression were used for analysis. SETTING: Suburban emergency medical service (EMS) system. PARTICIPANTS: Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arrival between July 1989 and July 1993. RESULTS: Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR were younger than those who did not: 62.5 +/- 15.4 years versus 66.8 +/- 15.1 years (P < .01). We found no differences in basic or advanced life support response intervals or in frequency of AED use. More patients initially had ventricular fibrillation (VF) in the BCPR group: 80.9% versus 61.4% (P < .01). The interval to definitive care for ventricular tachycardia (VT)/VF was longer for the BCPR group (8.59 +/- 5.3 versus 7.45 +/- 4.7 minutes; P < .05). The percentage of patients discharged alive who were initially in VT/VF was higher in the BCPR group: 18.3% versus 8.4% (P < .001). In a multivariate model, BCPR is a significant predictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% CI, 1.7 to 4.4) and 2.4 (95% CI, 1.5 to 4.0), respectively. For those patients in VT/VF, BCPR predicted live discharge from hospital with an adjusted OR of 2.1 (95% CI, 1.2 to 3.6). CONCLUSION: Patients who receive BCPR are more often found in VT/VF and have an increased rate of live discharge, with controls for age and response and definitive care intervals. For VT/VF patients, BCPR is associated with an increased rate of live discharge.

Adult↗

Sensitivity of the Ottawa rules.

STUDY OBJECTIVE: To validate criteria predicting ankle and mid-foot fractures with 100% sensitivity. DESIGN: Prospective validation study SETTING: A 929-bed community teaching hospital with an annual census of 76,488 ED visits. PARTICIPANTS: Convenience sample of patients older than 18 years with acute ankle or midfoot injury. INTERVENTIONS: Radiography was performed in each patient received after pertinent history and physical examination findings were recorded. RESULTS: Five hundred seventy radiographs were obtained in 484 patients. Four hundred twenty-one were of the ankle, and 149 were of the foot. There were 93 ankle fractures and 29 midfoot fractures, giving a fracture yield of 22.1% for ankle films and 19.5% for foot films. Decision rules had sensitivity of 94.6% and specificity of 15.5% for ankle fractures and sensitivity of 93.1% and specificity of 11.5% for midfoot fractures. Prospective criteria failed to predict fracture in five of the ankle group and two of the midfoot group. Physicians predicting fracture solely on the basis of clinical suspicion had a sensitivity of 69% in ankle injuries and 76% in midfoot injuries. CONCLUSION: We were unable to validate with 100% sensitivity the Ottawa rules predicting ankle and midfoot fractures. However, the Ottawa rules were more sensitive than clinical suspicion alone.

Adolescent↗