The Canadian C-spine rule for radiography in alert and stable trauma patients.

CONTEXT: High levels of variation and inefficiency exist in current clinical practice regarding use of cervical spine (C-spine) radiography in alert and stable trauma patients. OBJECTIVE: To derive a clinical decision rule that is highly sensitive for detecting acute C-spine injury and will allow emergency department (ED) physicians to be more selective in use of radiography in alert and stable trauma patients. DESIGN: Prospective cohort study conducted from October 1996 to April 1999, in which physicians evaluated patients for 20 standardized clinical findings prior to radiography. In some cases, a second physician performed independent interobserver assessments. SETTING: Ten EDs in large Canadian community and university hospitals. PATIENTS: Convenience sample of 8924 adults (mean age, 37 years) who presented to the ED with blunt trauma to the head/neck, stable vital signs, and a Glasgow Coma Scale score of 15. MAIN OUTCOME MEASURE: Clinically important C-spine injury, evaluated by plain radiography, computed tomography, and a structured follow-up telephone interview. The clinical decision rule was derived using the kappa coefficient, logistic regression analysis, and chi(2) recursive partitioning techniques. RESULTS: Among the study sample, 151 (1.7%) had important C-spine injury. The resultant model and final Canadian C-Spine Rule comprises 3 main questions: (1) is there any high-risk factor present that mandates radiography (ie, age >/=65 years, dangerous mechanism, or paresthesias in extremities)? (2) is there any low-risk factor present that allows safe assessment of range of motion (ie, simple rear-end motor vehicle collision, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness)? and (3) is the patient able to actively rotate neck 45 degrees to the left and right? By cross-validation, this rule had 100% sensitivity (95% confidence interval [CI], 98%-100%) and 42.5% specificity (95% CI, 40%-44%) for identifying 151 clinically important C-spine injuries. The potential radiography ordering rate would be 58.2%. CONCLUSION: We have derived the Canadian C-Spine Rule, a highly sensitive decision rule for use of C-spine radiography in alert and stable trauma patients. If prospectively validated in other cohorts, this rule has the potential to significantly reduce practice variation and inefficiency in ED use of C-spine radiography.

Canadian CT head rule study for patients with minor head injury: methodology for phase II (validation and economic analysis).

Prospective validation on a new set of patients is an essential test of a new decision rule. However, many clinical decision rules are not prospectively assessed to determine their accuracy, reliability, clinical sensibility, or potential impact on practice. This validation process is important because many statistically derived rules or guidelines do not perform well when tested in a new population. The methodologic standards for a validation study are similar to those described in the article on phase I for derivation studies in the August 2001 issue of Annals of Emergency Medicine. The goal of phase II is to prospectively assess the accuracy, reliability, and acceptability of the decision rule in a new set of patients with minor head injury. This will determine the clinical utility of the rule and is essential if such a rule is to be widely adopted into clinical practice.

The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation).

Head injuries are among the most common types of trauma seen in North American emergency departments, with an estimated 1 million cases seen annually. "Minor" head injury (sometimes known as "mild") is defined by a history of loss of consciousness, amnesia, or disorientation in a patient who is conscious and talking, that is, with a Glasgow Coma Scale score of 13 to 15. Although most patients with minor head injury can be discharged without sequelae after a period of observation, in a small proportion, their neurologic condition deteriorates and requires neurosurgical intervention for intracranial hematoma. The objective of the Canadian CT Head Rule Study is to develop an accurate and reliable decision rule for the use of computed tomography (CT) in patients with minor head injury. Such a decision rule would allow physicians to be more selective in their use of CT without compromising care of patients with minor head injury. This paper describes in detail the rationale, objectives, and methodology for Phase I of the study in which the decision rule was derived. [Stiell IG, Lesiuk H, Wells GA, McKnight RD, Brison R, Clement C, Eisenhauer MA, Greenberg GH, MacPhail I, Reardon M, Worthington J, Verbeek R, Rowe B, Cass D, Dreyer J, Holroyd B, Morrison L, Schull M, Laupacis A, for the Canadian CT Head and C-Spine Study Group. The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation). Ann Emerg Med. August 2001;38:160-169.]

The Canadian CT Head Rule for patients with minor head injury.

BACKGROUND: There is much controversy about the use of computed tomography (CT) for patients with minor head injury. We aimed to develop a highly sensitive clinical decision rule for use of CT in patients with minor head injuries. METHODS: We carried out this prospective cohort study in the emergency departments of ten large Canadian hospitals and included consecutive adults who presented with a Glasgow Coma Scale (GCS) score of 13-15 after head injury. We did standardised clinical assessments before the CT scan. The main outcome measures were need for neurological intervention and clinically important brain injury on CT. FINDINGS: The 3121 patients had the following characteristics: mean age 38.7 years); GCS scores of 13 (3.5%), 14 (16.7%), 15 (79.8%); 8% had clinically important brain injury; and 1% required neurological intervention. We derived a CT head rule which consists of five high-risk factors (failure to reach GCS of 15 within 2 h, suspected open skull fracture, any sign of basal skull fracture, vomiting >2 episodes, or age >65 years) and two additional medium-risk factors (amnesia before impact >30 min and dangerous mechanism of injury). The high-risk factors were 100% sensitive (95% CI 92-100%) for predicting need for neurological intervention, and would require only 32% of patients to undergo CT. The medium-risk factors were 98.4% sensitive (95% CI 96-99%) and 49.6% specific for predicting clinically important brain injury, and would require only 54% of patients to undergo CT. INTERPRETATION: We have developed the Canadian CT Head Rule, a highly sensitive decision rule for use of CT. This rule has the potential to significantly standardise and improve the emergency management of patients with minor head injury.

Coronary angiography using 4 Fr catheters with acisted power injection: A randomized comparison to 6 Fr manual technique and early ambulation.

Coronary angiography using 4 Fr catheters may reduce access site complications, promote better utilization of outpatient facilities, but at a cost of suboptimal image quality. To determine whether 4 Fr diagnostic angiography with power injection (Acist, Minneapolis, MN) was equivalent to 6 Fr manual technique, 101 unselected patients were randomized to transfemoral coronary angiography with 4 or 6 Fr catheters. Procedural characteristics, angiographic quality scores, and results of 90 min ambulation were analyzed. Coronary angiographic quality scores using 4 Fr and 6 Fr catheters were equivalent (left coronary artery 4.73 +/- 0.6 vs. 4.80 +/- 0.65, P = 0.28; right coronary artery 4.98 +/- 90.13 vs. 4.97 +/- 0.16, P = 0.48). However, 4 Fr left ventriculographic image score was lower (4.53 +/- 0.68 vs. 4.83 +/- 0.42, P = 0.0002), attributed, in part, to a smaller injected contrast volume (32 +/- 11 vs. 37 +/- 4 mL, P = 0.001). The total study contrast volume was significantly less in the 4 Fr group (119 +/- 35 vs. 159 +/- 52 mL, P = 0.001). Complications related to early ambulation at 90 min were similar and minimal in both groups. Compared to 6 Fr manual contrast injection technique, diagnostic angiography through 4 Fr catheters with power contrast injection resulted in equivalent coronary angiographic image quality, slightly reduced but diagnostic left ventricular image quality, and significantly less contrast volume. Four Fr angiography facilitates early ambulation without compromising safety and image quality.

Coronary steal by IMA bypass graft side-branches: a novel therapeutic use of a new detachable embolization coil.

Coronary artery steal syndromes following coronary artery bypass grafting (CAB) may occur as a result of the presence of large side-branches arising from the internal mammary artery (IMA). We report the first successful deployment of a new detachable vascular embolization coil device to occlude the IMA side-branches in two patients. Optimal positioning is easily obtained with the unique operator-controlled, safety-release protected mechanism of this device. Complete retraction is possible, with safe and efficient removal of the coil even after deployment. This feature was appreciated during one procedure in which the initially selected coil was found to be oversized, requiring immediate removal. Acute thrombo-occlusion of the IMA side-branches in both patients was observed. We conclude that IMA bypass graft side-branches causing coronary steal can be safely and effectively occluded using this new technique. However, due to observed delayed partial recanalization noted on distant follow-up angiography, we recommend placement of multiple coils at the time of initial embolization.

Prevalence of aortocoronary graft marker use and the factors affecting this decision.

BACKGROUND: Despite quantifiable evidence that aortocoronary graft marker (ACGM) insertion is associated with a beneficial impact at postoperative angiography, the choice whether or not to insert them at the time of bypass surgery remains optional. METHODS: A one-time anonymous membership survey of the Society of Thoracic Surgeons was used to determine the prevalence of ACGM use and obtain demographic data regarding (1) the type of ACGM inserted, (2) reasons influencing the decision as to whether or not to use ACGMs, and (3) the occurrence of possible related complications. RESULTS: Thirty-nine percent (1,405 of 3,558) and 37% (198 of 531) were returned from within and outside the Unites States, respectively. Sixty percent of US respondents routinely insert ACGMs in the majority of their individual cases. The most frequent reason to not insert ACGMs was a "lack of perceived benefit." CONCLUSIONS: The majority of respondents practicing within the United States routinely insert ACGMs at the time of surgery. As no complication directly attributable to the use of graft markers has been reported, further study is warranted to determine the actual complication rate, although it is expected to be low.

Impact of aorto-coronary graft markers on subsequent graft patency: a retrospective review.

The use of aorto-coronary graft markers has not been standard, presumably due to concern about possible adverse effects on subsequent graft patency. Our goal was to determine if there was any increased risk of graft occlusion in patients who received circumferential graft markers at the time of their coronary artery bypass (CAB) surgery. A retrospective review of angiograms was performed for patients with prior CAB. Cohorts with and without graft markers were compared. A total of 405 "unmarked" and 311 "marked" grafts were identified in 335 patients meeting inclusion criteria. Patency is reported in divisions of elapsed time since CAB. Overall patency in the "marked" group (71.1%) was significantly higher than in the "unmarked" group (58.0%, P < 0.001). In this retrospective population, there was no increased risk of graft occlusion in patients who received circumferential graft markers at the time of CAB surgery as compared to those patients who did not.

Preoperative gadolinium-enhanced magnetic resonance pulmonary venography in an adolescent with atrial septal defect.

The conventional preoperative evaluation of congenital heart disease in the adult using only echocardiography and cardiac catheterization is frequently limited. We report a case in which newer magnetic resonance imaging with gadolinium angiographic techniques proved helpful by conclusively documenting normal pulmonary venous return in a patient with secundum [corrected] atrial septal defect. This evaluation obviated the need for referral to a more specialized tertiary-care center for congenital heart disease and dramatized the value of an interdisciplinary approach to the adult patient with newly diagnosed congenital heart disease.

Variation in ED use of computed tomography for patients with minor head injury.

STUDY OBJECTIVE: To determine the frequency of utilization, yield for brain injury, incidence of missed injury, and variation in the use of computed tomography (CT) for ED patients with minor head injury. METHODS: This retrospective health records survey was conducted over a 12-month period in the EDs at seven Canadian teaching institutions. Included in this review were adult patients who sustained acute minor head injury, defined as witnessed loss of consciousness or amnesia and a Glasgow Coma Scale score of 13 or greater. Data were collected by research assistants who were trained to select cases and abstract data in a standardized fashion according to a resource manual. Subsequently, patient eligibility was reviewed by the study coordinator and principal investigator. RESULTS: Of the 1,699 patients seen, 521 (30.7%) were referred for CT, and 418 (79.8%) of these scans were negative for any type of brain injury. Overall, 105 (6.2%) of these patients sustained acute brain injury, including 9 (.5%) with an epidural hematoma Cochran's Q test for homogeneity demonstrated significant variation between the seven centers for rate of ordering CT (P < .0001), from a low of 15.9% to a high of 70.4%. All five cases of "missed" hematoma occurred at the institutions with the highest and third highest rates of CT use. After controlling for possible differences in case severity and patient characteristics at each hospital, logistic regression analysis revealed that five of seven hospitals were significantly associated with the use of CT (respected odds ratios [OR], .4, .5, .5, 3.2, and 4.7). Three of the centers (two with the highest ordering rates) showed significant heterogeneity in the ordering of CT among their attending staff physicians, from a low of 6.5% to a high of 80.0%. CONCLUSION: There was considerable variation among institutions and individual physicians in the ordering of CT for patients with minor head injury. Although emergency physicians were selective when ordering CT, the yield of radiography was very low at all hospitals. None of the cases of "missed" intracranial hematoma came from the lowest ordering institutions, indicating that patients may be managed safely with a selective approach to CT use. These findings suggest great potential for more standardized and efficient use of CT of the head, possibly through the use of a clinical decision rule.

Variation in emergency department use of cervical spine radiography for alert, stable trauma patients.

OBJECTIVE: To, assess the emergency department use of cervical spine radiography for alert, stable adult trauma patients in terms of utilization, yield for injury and variation in practices among hospitals and physicians. DESIGN: Retrospective survey of health records. SETTING: Emergency departments of 6 teaching and 2 community hospitals in Ontario and British Columbia. PATIENTS: Consecutive alert, stable adult trauma patients seen with potential cervical spine injury between July 1, 1994, and June 30, 1995. MAIN OUTCOME MEASURES: Total number of eligible patients, referral for cervical spine radiography (overall, by hospital and by physician), presence of cervical spine injury, patient characteristics and hospitals associated with use of radiography. RESULTS: Of 6855 eligible patients, cervical spine radiography was ordered for 3979 (58.0%). Only 60 (0.9%) patients were found to have an acute cervical spine injury (fracture, dislocation or ligamentous instability); 98.5% of the radiographic films were negative for any significant abnormality. The demographic and clinical characteristics of the patients were similar across the 8 hospitals, and no cervical spine injuries were missed. Significant variation was found among the 8 hospitals in the rate of ordering radiography (p < 0.0001), from a low of 37.0% to a high of 72.5%. After possible differences in case severity and patient characteristics at each hospital were controlled for, logistic regression analysis revealed that 6 of the hospitals were significantly associated with the use of radiography. At 7 hospitals, there was significant variation in the rate of ordering radiography among the attending emergency physicians (p < 0.05), from a low of 15.6% to a high of 91.5%. CONCLUSIONS: Despite considerable variation among institutions and individual physicians in the ordering of cervical spine radiography for alert, stable trauma patients with similar characteristics, no cervical spine injuries were missed. The number of radiographic films showing signs of abnormality was extremely low at all hospitals. The findings suggest that cervical spine radiography could be used more efficiently, possibly with the help of a clinical decision rule.

Beneficial impact of aorto-coronary graft markers on post-operative angiography.

OBJECTIVE: When coronary and graft angiography is required for patients with prior coronary artery bypass (CAB) graft surgery, it is often difficult to localize the proximal aorto-coronary graft anastamosis. Our goal was to quantify the potential benefit during subsequent angiography if the proximal anastamosis is marked by an aorto-coronary graft marker at the time of CAB. METHODS: Retrospective review of 414 angiograms that were performed for patients with prior CAB. Cohorts with an without graft markers were compared. RESULTS: In the group with aorto-coronary graft markers and > or = 2 aorto-coronary grafts, there were significant reductions in fluoroscopy time (30.5%, p < 0.0001), contrast volume (21.7%, p < 0.0001), and numbers of angiographic catheters used (17.0%, p = 0.0001). If only one aorto-coronary graft was placed and marked, a trend toward reduced fluoroscopy time was observed (23.8%, p = 0.07). CONCLUSIONS: This study demonstrates the objective benefit supporting routine placement of circumferential aorto-coronary graft markers during CAB, particularly if > 1 graft is required.

The Ontario trial of active compression-decompression cardiopulmonary resuscitation for in-hospital and prehospital cardiac arrest.

OBJECTIVE: To compare the impact of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) and standard CPR on the outcomes of in-hospital and prehospital victims of cardiac arrest. DESIGN: Randomized controlled trial with blinding of allocation using a sealed container. SETTINGS: (1) Emergency departments, wards, and intensive care units of 5 university hospitals and (2) all locations outside hospitals in 2 midsized cities. PATIENTS: A total of 1784 adults who had cardiac arrest. INTERVENTION: Patients received either standard or ACD CPR throughout resuscitation. MAIN OUTCOME MEASURES: Survival for 1 hour and to hospital discharge and the modified Mini-Mental State Examination (MMSE). RESULTS: All characteristics were similar in the standard and ACD CPR groups for the 773 in-hospital patients and the 1011 prehospital patients. For in-hospital patients, there were no significant differences between the standard (n = 368) and ACD (n = 405) CPR groups in survival for 1 hour (35.1% vs 34.6%; P = .89), in survival until hospital discharge (11.4% vs 10.4%; P = .64), or in the median MMSE score of survivors (37 in both groups). For patients who collapsed outside the hospital, there were also no significant differences between the standard (n = 510) and ACD (n = 501) CPR groups in survival for 1 hour (16.5% vs 18.2%; P = .48), in survival to hospital discharge (3.7% vs 4.6%; P = .49), or in the median MMSE score of survivors (35 in both groups). Exploration of clinically important subgroups failed to identify any patients who appeared to benefit from ACD CPR. CONCLUSIONS: ACD CPR did not improve survival or neurologic outcomes in any group of patients with cardiac arrest.

Can a day 4 bone scan accurately determine the presence or absence of scaphoid fracture?

STUDY OBJECTIVE: To evaluate the accuracy of day 4 bone scans in predicting the presence or absence of fracture in patients with "clinical scaphoid fracture." DESIGN: Prospective sensitivity study of ED patients with clinical scaphoid fractures. Each patient was immobilized in a thumb spica cast and had day 4 bone scans of both wrists and hands. Blinded day 4 bone scan results were ultimately compared with the diagnosis on day 14 when patients returned for repeat clinical examination and radiographs. In cases of equivocal radiographic or clinical examination results, a day 14 bone scan was performed. SETTING: Two tertiary care teaching hospital emergency departments. PARTICIPANTS: All ED patients older than 16 years with the diagnosis of clinical scaphoid fracture were eligible. RESULTS: Ninety-nine patients were enrolled and successfully completed the study protocol from October 1990 through November 1992. One patient had bilateral injury, for a total of 100 completed studies. Day 4 bone scans were 100% sensitive and 92% specific, for a positive predictive value of 65%, a negative predictive value of 100%, and accuracy of 93% (95% confidence interval, 88%, to 98%). Many other types of fractures were identified on the day 4 scans, including those of the triquetra, distal radius, capitate, hamate, trapezoid, trapezium, and metacarpals. CONCLUSION: Day 4 bone scans are an accurate means of ruling out scaphoid fracture. However, because of a significant number of false-positive scans at day 4, they do not reliably confirm the diagnosis of scaphoid fracture. The bone scans also permitted identification of several other wrist fractures that had not been radiographically apparent.

[Recall errors in locating cities on a map]. / Der Rückschaufehler bei der Lokalisierung von Städten auf einer Landkarte.

Three experiments investigated whether hindsight bias--a systematic distortion of the recollections of numerical estimates--is also observed with visuo-spatial material. Subjects estimated the location of 20 German cities on an empty map, received feedback about the true locations, and were then requested to recall their earlier estimates. Additionally, we tested each subject's intelligence, field dependency, and visuo-spatial abilities. In experiment 1, in which experimental and control items (i.e. those with and without feedback) were given to the same subjects, hindsight bias was observed, but only in one out of three dependent measures. The same pattern of results emerged in experiment 2, despite the use of a different mode of data collection. Experiment 3, in which experimental and control items were given to different subjects, found a strong hindsight bias in all three dependent measures. The personality features showed no correlation with the amount of individual hindsight bias. All three experiments provided evidence that hindsight bias occurs with visuo-spatial material.