Article, Hematology

Association of physician risk tolerance with ED CT use for isolated dizziness/vertigo patients

Table

Correlations between StO2 and age, WBC, Hct, MCV, Plt, MPV, and RDW according to sex

Age

WBC

Hb

Hct

MCV

Plt

MPV

RDW

StO2 correlation for females

P: .048

P: .171

P: .894

P: .245

P: .264

P: .057

P: .058

P: .599

r: 0.244

r: -0.17

r:-0.017

r: 0.146

r:-0.141

r: 0.237

r:-0.236

r: 0.066

StO2 correlation for males

P: .639

P: .479

P: .337

P: .639

P: .123

P: .011

P: .207

P: .864

r: 0.060

r: 0.090

r: -0.122

r: 0.060

r: 0.195

r: 0.317

r: -0.16

r: -0.02

StO2 correlation for total

P: .639

P: .699

P: .269

P: .032

P: .944

P: .155

P: .016

P: .240

r: 0.06

r: 0.034

r: 0.098

r: 0.189

r: -0.006

r: 0.126

r:-0.211

r: 0.104

Abbreviation: Hb, hemoglobin (level).

distribution of platelets (Plts). The MPV is directly correlated with the rate of Plt production [2].

Near-infrared spectroscopy allows Noninvasive measurement of tissue oxygen saturation (StO2) [3,4], and literature has reported that it can be useful in determining the severity of hemorrhagic shock [5], fluid resuscitation [6], septic shock [7], and predicting multiple-organ dysfunction syndrome [8]. But there is a lack of data on its use in emergency practice [9].

To the best of our knowledge, no research has been peformed to date for evaluation of the relationship of StO2 levels and CBC parameters in the emergency department (ED). The aim of the present study was to determine the relationship between StO2 levels and CBC parameters of ED patients.

Approval of the human study committee of our medical faculty was provided for this study. The participants/relatives were informed and gave their informed consent. We examined 130 patients who were admitted to our ED and underwent laboratory evaluation. Age, sex, and CBC parameters including white blood cell count , hemoglobin level, hematocrit (Hct), mean corpuscular volume (MCV), red cell distribution width (RDW), Plt, and MPV levels of the patients were noted. For the StO2 level measurement, an InSpectra device was placed to the right thenar muscle for 10 seconds, and means of the first, fifth, and 10th second values were noted at the time of admission. In our study, we measured thenar muscle StO2 via wide-gap second-derivative near-infrared spectroscopy (InSpectra; Hutchinson Technology, Hutch- inson, MN). Cardiopulmonary arrest patients and patients less than age 18 years were excluded from the study.

The normal distribution and homogeneity of each parameter were tested using the Shapiro-Wilk test and the Kolmogorov-Smirnov test. Age and StO2 values did not suit the normal distribution. A Mann- Whitney U test was used for differences between and among the 2 groups. A spearman correlation test was used for correlation analysis. In all tests, the significance level was P b .05. SPSS (Chicago, IL) software 20.0 was used for analysis.

In our study, 66 (50.8%) female and 66 (48.2%) male for total of 130 patients were included. Mean age of our study group was 47.75 +-

18.91 (min,18; max, 80). The mean StO2 level of females was 80.52 +-

5.89 (min, 67; max, 92), and mean StO2 level of males was 78.50 +- 6.53 (min, 62; max, 93). Mean StO2 values of the sexes were significantly different (P = .02). Tissue oxygen saturation levels were correlated with Hct (P = .032, r = .189) and MPV(P = .016, r = -.211) levels. Detailed correlations between StO2 and age, WBC, Hct, MCV, Plt, MPV, and RDW according to sex are given in the Table.

Tissue oxygen saturation values are correlated with Hct and MPV levels. Tissue oxygen saturation level measurement may be helpful in predicting the Hct and MPV values of the ED patients.

Sadiye Yolcu, MD

Bozok University Department of Emergency Medicine

Yozgat, Turkey E-mail address: [email protected]

http://dx.doi.org/10.1016/j.ajem.2014.07.003

References

  1. Sandhaus LM, Meyer P. How useful are CBC and reticulocyte reports to clinicians? Am J Clin Pathol 2002;118(5):787-93.
  2. Threatte GA. Usefulness of the mean platelet volume. Clin Lab Med 1993;13(4): 937-50.
  3. Cohn SM. Near-infrared spectroscopy: potential clinical benefits in surgery. J Am Coll Surg 2007;205(2):322-32.
  4. Creteur J. Muscle StO2 in critically ill patients. Curr Opin Crit Care 2008;14(3):361-6.
  5. Beilman GJ, Blondet JJ. Near-infrared spectroscopy-derived tissue oxygen saturation in battlefield injuries: a case series report. World J Emerg Surg 2009; 4:25.
  6. George ME, Beilman GJ, Mulier KE, et al. Noninvasive tissue oxygen saturation measurements identify supply dependency. J Surg Res 2010;160 (1):40-6.
  7. Rodriguez A, Lisboa T, Martin-Loeches I, et al. Mortality and regional oxygen saturation index in septic shock patients: a pilot study. J Trauma 2011;70(5): 1145-52.
  8. Cohn SM, Nathens AB, Moore FA, et al. Tissue oxygen saturation predicts the development of organ dysfunction during traumatic shock resuscitation. J Trauma 2007;62(5):44-50 [Discussion].
  9. Yolcu S, Erdur B. Use of Tissue oxygenation (StO2) monitor in the ED. Am J Emerg Med 2014. http://dx.doi.org/10.1016/j.ajem.2014.04.037.

    Association of physician risk tolerance with ED CT use for isolated dizziness/vertigo patients?,??

    Dizziness/vertigo is one of the most common principal complaints in the emergency department (ED) [1], accounting for 2.5% of all ED presentations [2]. Although the most common causes of dizziness/vertigo are benign, potential life-threatening stroke especially cerebellar or brain stem infarction should be considered in the differential diagnosis because isolated dizziness without other concurrent neurologic symptoms can be the sole presentation of these conditions [3-5]. Noncontrast brain computed tomography (CT) provides the necessary information for emergency management of most patients with suspected stroke and is the most commonly used brain imaging method in EDs [6]. The proportion of Cerebrovascular events in patients aged 44 years and older with dizziness as the main presenting symptom is as low as 0.7% [5], and the diagnostic yield of brain CT is only 2.2% [7]. However, an early definitive diagnosis is often difficult to make in patients with vague dizziness symptoms. Considering the consequences of misdiagnosis including potential critical disease and litigious risk, emergency physicians (EPs) may lower the testing threshold for brain imaging in managing these low-probability, high-morbidity situations.

    Previous studies have demonstrated that risk tolerance, perception of uncertainty, and malpractice fear were associated with physician practice variation and may drive physicians to practice risk-averse behavior [8-13]. The most risk averse and most malpractice concern quartiles of EPs were associated with higher admission rates and greater use of cardiac markers in patients with chest pain [9,10,12]. Personal risk-taking

    ? Prior presentations: The abstract of this manuscript has been presented as a poster in Australasian College for Emergency Medicine 30th Annual Scientific Meeting, 2013/11/24-28, Adelaide, Australia.

    ?? Funding sources/disclosures: No.

    Table 1

    Demographic characteristics of 3612 ED patients with isolated dizziness/vertigoa

    Characteristics

    Total patients

    n = 3612

    Patients with CT examination

    n = 715 (19.8%)

    Patients without CT examination

    n = 2897 (80.2%)

    P

    Age

    53.8 +- 16.99

    63.0 +- 16.15

    57.2 +- 17.00

    b.001

    Male

    1366 (37.8%)

    304 (42.5%)

    1062 (36.7%)

    .004

    Hypertension

    1551 (42.9%)

    363 (50.8%)

    1188 (41.0%)

    b.001

    Diabetes

    716 (19.8%)

    170 (23.8%)

    546 (18.8%)

    .003

    Previous TIA/stroke

    301 (8.3%)

    88 (12.3%)

    213 (7.4%)

    b.001

    CAD history

    121 (3.3%)

    30 (4.2%)

    91 (3.1%)

    .16

    Hypercholesterolemia

    549 (15.2%)

    127 (17.8%)

    422 (14.6%)

    .033

    Atrial fibrillation

    82 (2.3%)

    25 (3.5%)

    57 (2.0%)

    .014

    Current smoker

    113 (3.1%)

    26 (3.6%)

    87 (3.0%)

    .384

    Alcoholism

    36 (1.0%)

    7 (1.0%)

    29 (1.0%)

    .958

    Admission

    251 (6.9%)

    157 (19.0%)

    94 (3.2%)

    b.001

    Final diagnosis of

    23 (0.6%)

    21 (2.9%)

    2 (0.1%)

    b.001

    central origin

    Abbreviations: TIA, transient ischemic attack; CAD, coronary artery disease.

    a Data are presented as mean +- SD or number (percentage).

    Fig. 1. Forest plot of adjusted OR of CT use in each RTS quartilea. arisk-taking subscale 1 indicates the most risk-averse group.

    behavior has been shown to be predictive of imaging use in patients who present with abdominal pain [8]. Computed tomography pulmonary angiography was ordered by 53% of physicians merely based on the fear of missing a pulmonary embolism, and this reasoning was associated with decreased odds of positive examination [14]. Unnecessary head CT examination may lead to increased length of ED stay [15], Medical costs, and radiation exposure (a potential carcinogen) [16,17]. Furthermore, variations in physician practice based on differences in risk tolerance may lead to subOptimal care, inefficient use of resources, and increased health care costs [9].

    To our knowledge, few studies have focused on the relationship between physician risk tolerance and head CT use in patients with isolated dizziness or vertigo, which are complaints encountered daily in EDs. Therefore, the purpose of this study was to evaluate the association between physician risk tolerance and head CT use in ED patients with isolated dizziness/vertigo. We hypothesized that CT use would be higher for more risk-averse physicians than for less risk-averse physicians.

    A retrospective study was conducted between July 1, 2011, and June 30, 2012 in an urban Tertiary medical center with an average of 72000 ED visits per year. The medical records of nontraumatic patients who were older than 17 years old and visited the ED with a principal diagnosis of dizziness and vertigo were extracted from the

    Table 2

    Computed tomography use, hospital admission, and final diagnosis of central origin dizziness/vertigo for the RTS, SUS, and MFS quartiles

    CT exam no. (%)

    P

    Admission no. (%)

    P

    Central origin no. (%)

    P

    RTS

    Q1a

    233 (22.19%)

    b.001

    69 (6.6%)

    .088

    8 (0.7%)

    .117

    Q2

    222 (18.94%)

    72 (6.1%)

    11 (0.9%)

    Q3

    182 (22.25%)

    73 (8.9%)

    4 (0.5%)

    Q4

    78 (13.6%)

    37 (6.5%)

    0 (0%)

    SUS

    Q1

    187 (19.83%)

    b.001

    48 (6.5%)

    .3

    3 (0.3%)

    .463

    Q2

    123 (17.23%)

    98 (8.1%)

    6 (0.8%)

    Q3

    293 (24.12%)

    47 (6.6%)

    5 (0.4%)

    Q4

    112 (15.14%)

    58 (6.2%)

    9 (1.2%)

    MFS

    Q1

    162 (27.5%)

    b.001

    44 (7.5%)

    .095

    6 (1.0%)

    .228

    Q2

    198 (20.25%)

    75 (7.7%)

    3 (0.3%)

    Q3

    218 (18.55%)

    88 (7.5%)

    10 (0.9%)

    Q4

    137 (15.75%)

    44 (5.1%)

    4 (0.5%)

    Abbreviation: Q, quartile.

    a Q1 represents the most risk-averse (lowest risk-taking behavior, highest stress from uncertainty, and most malpractice concern) group, and Q4 represents the most risk-tolerant group.

    ED administrative database using the International Classifications of Diseases Ninth Revision Coding system (dizziness, code 7804 and vertigo, codes 386.0 and 386.1). Electronic charts were reviewed to identify patients with isolated dizziness/vertigo. Patients with isolated dizziness/vertigo were defined as those with a primary complaint of dizziness or vertigo but without documented evidence of stroke who were screened by ED clinicians. Patients with documented newly onset abnormal neurologic finding including cranial nerve examination, cerebellar function tests, or muscle power or sensory change were excluded. The study was approved by our hospital’s institutional review board.

    We used 3 scales to evaluate physician risk tolerance attitude:

    (1) risk-taking subscale (RTS) of the Jackson Personality Index, (2) stress from uncertainty scale (SUS), and (3) malpractice fear scale (MFS). These scales have been used in prior studies to evaluate EP decision making and test-ordering behavior [8-10]. The detailed questionnaires for each survey instrument are listed in the Appendix.

    During the study period, we had a total of 17 EPs in our department. Emergency physicians were blinded to the study design. In July 2012, all EPs completed a survey consisting of 3 questionnaires. Physicians were divided into quartiles based on their 3 test scores, with quartile 1 in each case being the group expected (a priori) to be most risk averse (low risk takers, higher stress from uncertainty, and more fearful of Malpractice litigation). None of these physicians was ever deposed in a lawsuit as a defendant within the past 5 years. In our ED, residents help evaluate

    aMFS 1 indicates the most malpractice concern group. MFS, malpractice fear scale.

    Fig. 2. Forest plot of adjusted odd ratios of CT use in each MFS quartilea. aMalpractice fear scale 1 indicates the most malpractice concern group.

    aMFS 1 indicates the most malpractice concern group, and RTS 1 indicates the most risk-averse group.

    Fig. 3. The trend and percentage of patients receiving CT examination in the MFS and RTS quartiles. aMalpractice fear scale 1 indicates the most malpractice concern group, and RTS 1 indicates the most risk-averse group.

    patients, but the EPs make the final decision regarding CT examination scheduling and admission. The EPs were paid according to the number of shifts worked and not the number of patients treated; therefore, test ordering was not profit motivated.

    Age, sex, triage level, and risk factors for ischemic stroke including hypertension, diabetes, previous transient ischemic attack/stroke, coronary artery disease, hypercholesterolemia, atrial fibrillation, current smoker, and alcoholism [5] were collected from the medical record charts. Patient disposition, ED length of stay , and final discharge diagnosis of central nerve system (CNS) origin dizziness/vertigo by a neurologist were also documented. The primary outcome was brain CT use during ED evaluation, and the secondary outcome was hospital admission.

    The results of the descriptive analyses of independent variables are reported as percentages or means +- SDs. Independent variables were analyzed using ?2, Mann-Whitney U, and Student t tests. To determine whether physician risk scores were associated with the decision to order a head CT and admit to the hospital, the EPs were categorized into 4 quartiles based on risk tolerance scores. The relationship of risk tolerance category with CT use and hospital admission was analyzed using the ?2 test, and logistic regression was used to obtain the odds ratio (OR), 95% confidence interval (CI), and P value for trends. A P b .05 was regarded as statistically significant. SPSS version 16.0 (SPSS, Inc., Chicago, IL) was used for all statistical analyses.

    During the study period, a total of 73595 patients visited the ED, and 3691 (5.02%) of these patients had dizziness or vertigo as their primary diagnosis. Seventy-nine patients were excluded because of a chart-documented new neurologic deficit, and the remaining 3612 patients composed our study group. The patients were assessed by the 17 EPs in our department, and the median number of patients assessed by each EP was 228. Among the 17 EPs, the median of the MFS, RTS, and SUS was 23 (interquartile range [IQR], 19-25), 21 (IQR, 20-23), and 50

    (IQR, 43-57), respectively.

    The demographic characteristics of the study group and the 715 (19.8%) patients who received brain CT examination in the ED are listed in Table 1. Two hundred fifty-one (6.9%) patients were admitted with CNS origin dizziness/vertigo. Of the 23 (0.64%) patients who received a final diagnosis of CNS origin disease by a neurologist during discharge, 10 patients had a posterior circulation ischemic lesion including vertebrobasilar insufficiency, 10 patients had a hemisphere ischemic lesion, 1 patient had chronic subdural hemorrhage, and 2 patients had a brain tumor.

    Univariate analysis revealed that EPs tended to order brain CTs in older (P b .001) and male (P = .004) patients and patients with hypertension (P b .001), diabetes (P = .003), previous transient ischemic attack/stroke (P b .001), hypercholesterolemia (P = .033), and atrial fibrillation (P = .014).

    As shown in Table 2, risk tolerance based on RTS, SUS, and MFS scores was significantly associated with a higher likelihood of head CT use (P b .001).

    Physicians who were relatively risk averse and more stressed when facing uncertainty and those who possessed a higher level of malpractice fear were more likely to order CT examinations in patients with isolated dizziness/vertigo.

    To determine whether patient age was a factor influencing CT use in EP quartiles, patients were divided into 2 age groups (<= 65 and N 65 years), and hierarchical analysis was performed. The more risk-averse physicians ordered more CTs for patients in both the older (19% vs 11.1%; P = .016) and younger age groups (27.2% vs 17.2%; P = .001) compared with the most risk-tolerant physicians. Similarly, physicians who possessed a high level of malpractice fear showed an increased probability of ordering CT examinations in both younger (19.9% vs 11.8%; P = .01) and older patients (21.3% vs

    19.3%; P = .001).

    The admission rate and final diagnostic rate of CNS origin dizziness/vertigo were not significantly different between the RTS, SUS, and MFS quartiles (Table 2). Patient admission rates for the most risk-averse and most risk-tolerant physicians were 6.6% and 6.5%, respectively (P = .088), and patient admission rates for physicians with high and low levels of malpractice fear were 7.5% and 5.1%, respectively (P = .095).

    After performing multivariate logistic regression to adjust patient- level confounding factors including risk factors for ischemic stroke, a significant association between RTS and MFS quartiles and head CT use was observed (Figs. 1 and 2). Compared with the most risk- tolerant physicians based on RTS, the most risk-averse physicians demonstrated a statistically significant increased probability of ordering a CT examination (22.19% vs 13.6%; P b .001, OR = 1.8, CI: 2.43-1.38). Similar results were obtained in each RTS quartile level (Fig. 1). Compared with EPs categorized into the lowest MFS quartile, physicians categorized into the highest MFS quartile showed a higher probability of ordering CT examinations (Fig. 2). The physicians in the lowest MFS quartile ordered brain CT examinations in only 15.75% of patients, whereas those in the highest and second highest quartiles ordered brain CT examinations in 27.50% and 20.25% of patients, respectively (P b .001). Significant trends in CT use were observed for RTS and MFS scores (trend for RTS score, P = .003; trend for MFS score, P b .001; Fig. 3). The most risk-averse physicians and physicians with the highest level of malpractice concern ordered more CT examinations compared with the least risk-tolerant physicians and physicians with lower levels of malpractice concern (Fig. 3). Stress from uncertainty scale quartiles and head CT use were not significantly associated after adjusting for patient-level confounding factors (OR = 0.7; CI: 1.01-0.6).

    Emergency department LOS was not significantly associated with

    RTS or MFS. Although ED LOS was slightly higher for patients of the most risk-averse physicians than for those of the most risk-tolerant physicians, this difference was not statistically significant (406.3 +- 559.34 vs 378.5 +- 564.65 min; P = .133). Similarly, patients of physicians in the highest MFS quartile had a longer ED LOS than those of physicians in the lowest MFS quartile; however, this difference was not statistically significant (408.1 +- 579.02 vs 356.5 +- 585.83 min; P = .061).

    Only a small percentage of patients who present with dizziness in the ED receive a final diagnosis of cerebral vascular accident. A previous study indicated that the diagnostic rate of CNS origin dizziness was 0.7% in patients without neurologic signs who were aged older than 44 years [5]. In our study, only 23 (0.6%) patients were diagnosed with dizziness/vertigo of CNS origin, which was slightly

    lower than previously reported diagnostic rates. One possible reason for the lower diagnostic rate is that patients aged younger than 44 years were also included in our study. As age is a risk factor for stroke [5], it is reasonable that the proportion of patients with CNS origin diagnosis would be lower because more low-risk patients were included in our study. Another explanation is the reduced costs and nearly 100% coverage of emergency medical services provided by Taiwan National Health Care Insurance in our country. Previous studies have revealed that patients with health insurance were associated with increased utilization of diagnostic testing and nonurgent ED visits [18,19]. All of our study patients were covered by national insurance and only paid approximately 23 US dollars for ED medical services including CT. It is possible that the lower relative cost of ED medical services and high insurance coverage contributed to the increased nonurgent CT examinations in the ED and consequent lower proportion of patients with CNS origin dizziness.

    In a previous study, 810 (48%) of 1681 patients with dizziness symptoms [20] received head CT totaling $988200 in charges; however, only 0.74% of CT scans yielded clinically significant pathology requiring intervention. Despite the low positive diagnos- tic rate of CNS origin dizziness, CT use in the ED has increased greatly. From 1995 to 2004, the proportion of patients presenting to the ED with dizziness who underwent a CT scan increased 169% [2], whereas the proportion of patients who received a CNS-related diagnosis dropped 62% during the same period [15]. From 1998 to 2007, the prevalence of CT or magnetic resonance imaging use during ED visits for injury-related conditions increased significantly (6% vs 15%; P b .001 for trend) without changes in the number of patients who were either admitted to the hospital or intensive care unit [16]. Similarly in our study, differences in the admission rate, proportion of patients with a final CNS origin diagnosis, and ED LOS between RTS and MFS quartiles were nonsignificant, whereas the proportion of patients receiving CT increased significantly. Increased CT ordering without obvious clinical benefit by EPs who were risk averse or possessed a high level of malpractice fear implies that the clinical behavior of EPs is driven by defensive medicine and not by patient disposition or diagnosis. Defensive medicine is the Clinical response deviation from standard medical practice including unnecessary test ordering primarily to avoid liability rather than to benefit the patient [21]. Personal risk-taking behaviors and mal- practice fear have been proposed as contributors to defensive medical practice patterns [8-13]. To our knowledge, our study is the first to indicate that personal risk-taking behavior and malprac- tice fear are predictive of CT use for patients presenting to the ED with isolated dizziness/vertigo.

    In the present study, RTS showed more consistent, dependable,

    and broad-ranged compatibility for the evaluation of EP decision making in test ordering compared with MFS, whereas SUS was the least effective scale. In previous studies, higher malpractice concern was also found to be associated with an increasED referral rate to a specialist by the primary care physician [13], increased test-ordering decisions by neurologists [22], and increased use of diagnostic tests and hospitalization for Low-risk chest pain patients by EPs [10]. However, Pine et al [8] found that the MFS was not associated with increased imaging use in ED patients with abdominal pain or admission rate or cardiac marker use in patients with chest pain [9]. This variability in the association between EP decision making and malpractice fear suggests that malpractice fear may be a less generalizable concept in ED medical decision making [9]. Variations in litigation risk among study sites may contribute to differences in ED medical decision making. Furthermore, different clinical practice patterns may be affected by individual personality factors other than fear of malpractice.

    Compared with MFS, RTS, developed by Pearson et al [12], appears to be more predictive of medical decisions such as admission of ED patients with acute chest pain [9,12] and imaging use in ED patients

    with abdominal pain [8]. Risk-taking subscale also appears to be associated with higher overall patient costs [23]. Risk-taking behavior has also been found to be associated with the use of certain discretionary testing by general practitioners, such as the use of complete blood counts and rapid streptococcal tests [24,25]. It is possible that personal risk-taking behavior may be a more funda- mental characteristic that can predict resource use for a wide variety of testing and Clinical decisions [8].

    Stress from uncertainty scale is thought to be a measure of a physician’s reaction to uncertainty [26]. However, in our study, the effect of SUS on head CT use was not statistically significant after multivariate adjustment. Our finding is consistent with previous studies demonstrating that the SUS is not significantly correlated with ED medical decision making including admission rate for patients with chest pain [9,12] and imaging use in patients with abdominal pain [8]. Thus, SUS does not seem to drive medical decision making in the ED.

    Emergency physicians have a unique role in ruling out potential Serious diseases in unfamiliar patients in a stressful environment. Most (93%) physicians in high-risk specialties reported practicing defensive medicine, and 63% of EPs ordered Radiologic tests in clinically unnecessary situations [21]. In our study, EPs in the most risk-averse quartile of RTS and MFS had 1.63 to 1.74 times the odds of CT ordering compared with EPs in the most risk-tolerant quartiles of RTS and MFS, resulting in 8.59 to 11.75 more CT examinations per 100 patients. Therefore, if all the patients in our study were treated by the most risk-tolerant EPs, Medical costs could have been reduced approximately $55000 per year (3612 patients x $152 CT cost in Taiwan) while maintaining the same diagnostic rate. The reductions in medical resource costs would be 8 times greater in the United States, where head CT cost is $1220 [20]. Given the enormous Financial burden of medical care, further interventions to decrease medical costs by improving variations in physician behavior should be considered. However, clinical decision making is very complex and may vary depending on multiple factors; therefore, devising an intervention to lower EPs’ perceived risk of malpractice or alter deeply ingrained personality traits that may affect risk attitude may be impossible [12]. Our opinion, which is supported by previous studies [10,12], is that it may be more practical to consider establishing guidelines that provide more clear-cut instruction in ambiguous clinical situations. Previous studies have demonstrated that head CT use in adult and pediatric ED trauma patients was not significantly associated with physician risk tolerance or malpractice fear [11,27]. This lack of association may be attributed to the well-validated clinical decision rules that are available to guide imaging use in these patients [27]. These studies suggest that opportunities for quality improvement exist. Identification of central or serious vertigo was the second priority in an international survey that identified the sampled EPs’ priorities for the development of clinical decision rules [28]. Additional studies are required to validate our findings, and further efforts to develop practical and reliable guidelines for CT use in ED patients with dizziness/vertigo are warranted.

    The retrospective nature of our study may have prevented

    Hawthorne effect; however, several limitations were present. First, the retrospective nature and relatively small sample number of EPs at the single teaching hospital may limit the implications and general- izability of the conclusions to other ED settings. Second, the relatively small number of patients with CNS diagnosis may have limited the statistical power of between-group analyses. Third, the current study was conducted in a single country. Malpractice fear may vary among ED physicians in distinct litigious environments. Finally, the fear of litigation by ED physicians may vary over time; therefore, the scales used in this study may not reflect the emotional state of the physician during patient treatment. Future large-scale prospective studies should aim to replicate our findings as well as other clinical problems in other practice settings.

    Individual EP risk tolerance measured by RTS and malpractice concern measured by MFS were predictive of CT use in patients with isolated dizziness/vertigo, whereas the SUS was not predictive of CT use. The information gained from this study may help practicing physician adjust their clinical behavior and lead to the implementa- tion of guidelines that will decrease unnecessary examinations.

    Appendix. Constructs for each survey instrument for risk tolerance evaluation

    risk-taking scale: each item is rated on a 6-point Likert scale

    I enjoy taking risks

  10. I try to avoid situations that have uncertain outcomes
  11. Taking risks does not bother me if the gains involved are high
  12. I consider security an important element in every aspect of my life
  13. People have told me that I seem to enjoy taking chances
  14. I rarely, if ever, take risks when there is another alternative

    Stress from uncertainty scale: each item is rated on a 6-point Likert scale

    The uncertainty of patient care often troubles me

  15. Not being sure of what is best for a patient is one of the most stressful parts of being a physician
  16. I am tolerant of the uncertainties present in patient care
  17. I find the uncertainty involved in patient care disconcerting
  18. I usually feel anxious when I am not sure of a diagnosis
  19. When I am uncertain of a diagnosis, I am imaging all sorts of bad scenarios– patient dies, patient sues, etc
  20. I am frustrated when I do not know a patient’s diagnosis
  21. I fear being held accountable for the limits of my knowledge
  22. Uncertainty in patient care makes me uneasy
  23. I worry about malpractice when I do not know a patient’s diagnosis
  24. The vastness of the information that physicians are expected to know overwhelms me
  25. I frequently wish I had gone into a specialty or subspecialty that would minimize the uncertainties of patient care
  26. I am quite comfortable with the uncertainty in patient care

    Malpractice fear scale: each item is rated on a 5-point Likert scale

    I have had to make significant changes in my practice pattern because of recent legal developments concerning medical delivery

  27. I am concerned that I will be involved in a malpractice case sometime in the next 10 years
  28. I feel pressured in my day-to-day practice by the threat of malpractice litigation
  29. I order some tests or consultations simply to avoid the appearance of malpractice
  30. Sometimes I ask for consultant opinions primarily to reduce my risk of being sued
  31. Relying on clinical judgment rather than on technology to make a diagnosis is becoming riskier from a medicolegal perspective

    Fu-Jen Cheng, MD Chien-Hung Wu, MD

    Department of Emergency Medicine Kaohsiung Chang Gung Memorial Hospital Chang Gung University College of Medicine Kaohsiung County 833, Taiwan

    Yuan-Jhen Syue, MD

    Department of Anesthesiology Kaohsiung Chang Gung Memorial Hospital Chang Gung University College of Medicine Kaohsiung County 833, Taiwan

    Pai-Chun Yen, MD Kuan-Han Wu, MD?

    Department of Emergency Medicine Kaohsiung Chang Gung Memorial Hospital Chang Gung University College of Medicine Kaohsiung County 833, Taiwan

    ?Corresponding author at: 21F-3, No. 123-11, Dapi Rd Niaosong Township, Kaohsiung County 833, Taiwan (ROC)

    E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.07.022

    References

    Burt CW, Schappert SM. Ambulatory care visits to physician offices, hospital outpatient departments, and emergency departments. Vital Health Stat 2004;13: 1-70.

  32. Kerber KA, Meurer WJ, West BT, Fendrick AM. Dizziness presentations in U.S. emergency departments, 1995-2004. Acad Emerg Med 2008;15:744-50.
  33. Gomez Camilo R, Cruz-Flores S, Malkoff M, Sauer CM, Burch CM. Isolated vertigo as a manifestation of vertebrobasilar ischemia. Neurology 1996;47:94-7.
  34. Lee H, Sohn S-I, Cho Y-W, Lee S-R, Ahn B-H, Park B-R, et al. Cerebellar infarction presenting isolated vertigo. Neurology 2006;06:1178-83.
  35. Kerber KA, Brown DL, Lisabeth LD, Smith MA, Morgenstern LB. Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study. Stroke 2006;37:2484-7.
  36. Jauch Edward C, JLS, Adams Jr Harold P, Bruno Askiel, Connors JJ, Demaerschalk Bart M, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the american heart association/American Stroke Association. Stroke 2013;44: 870-947.
  37. Lawhn-Heath C, Buckle C, Christoforidis G, Straus C. Utility of head ct in the evaluation of vertigo/dizziness in the emergency department. Emerg Radiol 2013; 20:45-9.
  38. Pines JM, Hollander JE, Isserman JA, Chen EH, Dean AJ, Shofer FS, et al. The association between physician risk tolerance and imaging use in abdominal pain. Am J Emerg Med 2009;27:552-7.
  39. Pines JM, Isserman JA, Szyld D, Dean AJ, McCusker CM, Hollander JE. The effect of physician risk tolerance and the presence of an observation unit on decision making for ed patients with chest pain. Am J Emerg Med 2010;28: 771-9.
  40. Katz DA, Williams GC, Brown RL, Aufderheide TP, Bogner M, Rahko PS, et al. Emergency physicians’ fear of malpractice in evaluating patients with possible Acute cardiac ischemia. Ann Emerg Med 2005;46:525-33.
  41. Wong AC, Kowalenko T, Roahen-Harrison S, Smith B, Maio RF, Stanley RM. A survey of emergency physicians’ fear of malpractice and its association with the decision to order computed tomography scans for children with minor head trauma. Pediatr Emerg Care 2011;27:182-5.
  42. Pearson SD, Goldman L, Orav EJ, Guadagnoli E, Garcia TB, Johnson PA, et al. Triage decisions for emergency department patients with chest pain: do physicians’ risk attitudes make the difference? J Gen Intern Med 1995;10: 557-64.
  43. Franks P, Williams GC, Zwanziger J, Mooney C, Sorbero M. Why do physicians vary so widely in their referral rates? J Gen Intern Med 2000;15:163-8.
  44. Rohacek M, Buatsi J, Szucs-Farkas Z, Kleim B, Zimmermann H, Exadaktylos A, et al. Ordering CT pulmonary angiography to exclude pulmonary embolism: defense versus evidence in the emergency room. Intensive Care Med 2012;38: 1345-51.
  45. Kerber KA, Schweigler L, West BT, Fendrick AM, Morgenstern LB. Value of computed tomography scans in ED dizziness visits: analysis from a nationally Representative sample. Am J Emerg Med 2010;28:1030-6.
  46. Korle Frederick Kofi, Pham Julius Cuong, Kirsch Thomas Dean. Use of advanced radiology during visits to us emergency departments for injury-related conditions, 1998-2007. JAMA 2010;304:1465-71.
  47. Colang JEKJ, Vano E. Patient dose from ct: a literature review. Radiol Technol 2007;

    79:17-26.

    Liu Tiepu, Sayre Michael R, Carleton Steven C. Emergency medical care: types, trends, and factors related to nonurgent visits; 1999.

  48. Mannix Rebekah, Chiang Vincent, Stack Anne M. Insurance status and the care of children in the emergency department. J Pediatr 2012;161:536-41.
  49. Ahsan Syed F, Yaremchuk Kathleen, Peterso Edward, Seidman Michael. The costs and utility of imaging in evaluating dizzy patients in the emergency room. Laryngoscope 2013;123:2250-3.
  50. Studdert David M, Mello Michelle M, Sage William M, DesRoches Catherine M, Peugh Jordon, Zapert Kinga, et al. Defensive medicine among high-risk specialist physicians in a volatile malpractice environment. JAMA 2005;293: 2609-17.
  51. Birbeck GL, Gifford DR, Song J, Belin TR, Mittman BS, Vickrey BG. Do malpractice concerns, payment mechanisms, and attitudes influence test-ordering decisions? Neurology 2004;62:119-21.
  52. Fiscella Kevin, Franks Peter, Zwanziger Jack, Mooney Cathleen, Sorbero Melony, Williams Geoffrey. Risk aversion and costs: a comparison of family physicians and general internists. J Fam Pract 2000;49:12-7.
  53. Zaat JOM, van Eijk Jacques ThM. General practitioners’ uncertainty, risk preference, and use of laboratory tests. Med Care 1992;30:846-54.
  54. Holtgrave DRLF, Spann SJ. Physicians’ risk attitudes, laboratory usage, and referral decisions: the case of an academic family practice center. Med Decis Making 1991;11: 125-30.
  55. Gerrity MS, White KP, DeVeilis RE, Dittus RS. Physicians’ reactions to uncertainty: refining the constructs and scales. Motiv Emot 1995;19:175-91.
  56. Andruchow James E, Prevedello Luciano M, Zane Richard D, Khorasani Ramin. Variation in head computed tomography use for emergency department trauma patients and physician risk tolerance. Arch Intern Med 2012;172: 660-1.
  57. Eagles D, Stiell IG, Clement CM, Brehaut J, Kelly AM, Mason S, et al. International survey of emergency physicians’ priorities for clinical decision rules. Acad Emerg Med 2008;15:177-82.