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Probability of appendicitis before and after observation
t procedure revealed a significant fluid deficit (495 mL) at five, six, and seven hours after ingestion versus none in the placebo group. ANOVAs for repeated measures did not reveal Statistical differences in orthostatic blood pressure changes for either group or time. Our results show that acute ethanol intoxication causes an early orthostatic pulse change, w h i c h resolves spontaneously as ethanol concentration decreases despite a delayed diuresis.
18 Evaluation of the Tilt Test in an Adult Emergency Department Population MA Levitt, M Lieberman, B Lopez, M Sutton/Thomas Jefferson University Hospital, Philadelphia, Pennsylvania Patients presenting to an urban emergency department with complaints suggestive of dehydration and/or blood loss were entered into a study to evaluate the "tilt test" in an adult ED population. As part of their evaluation, changes in heart rate and blood pressure from lying to standing were obtained in a standardized fashion. Body dehydration percent was calculated for each patient w i t h previously published calculations using measured serum osmolality and body weight. Internal or external bleeding was recorded if present. Mean dehydration percentage for this sample population (202) was 3.72 + 2.9. This sample was subdivided into those patients w i t h a diagnosis of blood loss (group 1) and those patients w i t h a diagnosis of dehydration (group 2). Mean dehydration percent for group 1 (36) was 2.73 ± 2.38 and group 2 (166) was 3.94 _+2.97 (P = .0226). Multiple A N O V A testing revealed syncope (P = .037) and lack of axillary sweat (P = .026) to be significantly correlated w i t h dehydration percentage. Symptomatic response to the tilt test was nonsignificant (P = .93). A forward stepwise linear regression model was constructed for the continuous variables {age, change in heart rate [HR], change in systolic pressure [SBP], and change in diastolic pressure [DP]) measured against dehydration percentage. In the whole sample and in group 2, the models found change in HR (P = .0165) and age (P = .0047) to demonstrate a true association with dehydration percentage. None of these variables were significant in the group 1 model. The authors conclude that in orthostatic m e a s u r e m e n t only HR and age have a true association w i t h level of dehydration. However, the a m o u n t of variation in dehydration percentage explained by HR and age is not clinically useful. These m e a s u r e m e n t s demonstrate no association with blood loss. It appears that there i s too m u c h individual variation in a patient's orthostatic response to dehydration and blood loss to determine degree or presence of dehydration or blood loss.
19 Probability of Appendicitis Before and After Observation LG Graft, MJ Radford, C Werne/New Britain General Hospital, New Britain, Connecticut; University of Connecticut Health Center, Farmington The effect of observation on the probability of appendicitis was examined retrospectively in 2 5 2 consecutive patients w i t h abdominal pain Who underwent short-term observation (10.4+ 1.7 hours) prior to the decision to operate. Alvarado.'s scoring system was used to assign a probability of appendicitis to each patient before and after observation. Mean score of patients w i t h appendicitis increased following observation from 6.8 + 0.6 to 7.8 ± 0.5 (P < .01 ), corresponding to a change in probability of appendicitis from 35% to 55%, Mean score of patients w i t h o u t appendicitis decreased from 3.8 ± 0.3 to 1.6 ± .02 (P < .01 ), corresponding to a change in probability from 8% to 3%. Following observation, the difference between m e a n scores of patients w i t h and w i t h o u t appendicitis increased from 2.6 ± 0.6 to 6.2 + .05 (P < .01). Two-by-two contingency table analysis showed that observation improved m e a n accuracy from 65% to 85% (P < .01 ), m e a n probability of diagnosis (positive predictive value)from 70% to 80% (P < .01 ), m e a n specificity from 65% to 86% (P < .01), and m e a n sensitivity from 70% to 80% (NS). By incorporating change in score following observation as a function of preobservation score, sensitivity further increased from 80% to 93 % (P < .01 ), and patients w i t h appendicitis could be separated from those without. In this group of patients with an initial intermediate probability of having appendicitis, observation improved the ability to distinguish patients w i t h and w i t h o u t appendicitis.
20 Threatened Abortion: A Prospective Study of Predictors of Outcome in an Emergency Department Population 18:4 April 1989
J Abbott, M Zaccardi, SR Lowenstein/Department of Surgery, Division of Emergency Medicine and Trauma, Emergency Medicine Clinical Research Center, University of Colorado Health Sciences Center, Denver Although threatened abortion is a c o m m o n problem in the emergency department, no prospective studies in an ED setting have been reported. We examined prospectively the presentation, clinical course, and outcome of 75 consecutive threatened abortion patients in our urban teaching hospital. All patients were in the first half of pregnancy and had vaginal bleeding, a closed cervix, and a positive pregnancy test. While a 50% rate of fetal loss is often quoted for threatened abortion patients, almost three quarters (72%) of our patients had fetal demise; only 28% had a good outcome (pregnancy viable at 20 weeks). Two fetal demises were ectopic. Obstetric history, race, maternal age, hematocrit, vital signs, presence and duration of cramps, presence of clots or abdominal tenderness on examination, and duration of bleeding were not helpful in predicting outcome. The time since last menstrual period was helpful: average time was 90 ± 8 days for good outcome patients versus 64 + 3 days for patients w i t h fetal loss (P = .008). Also, patients w i t h active bleeding were more likely to suffer fetal loss (RR = 2.3, P = .03}. The presence of fetal heart activity by ultrasound was a strong predictor of good outcome (P < .001). Also, a quantitative h u m a n chorionic gonadotropin (HCG) level < 6,500 m I U / m L (P < .001) and the absence of a gestational sac by uhrasound (P < .001) were strong predictors of bad outcome. For patients w i t h an H C G > 6,500 m I U / m L and no fetal heart activity, the chance of a good outcome was only one in five. All patients w i t h an H C G < 6,500 m I U / m L had fetal demise.
21 Predictors of Electrolyte Abnormalities in Elderly Patients BM Singal, JR Hedges, PA Succop/Departments of Emergency Medicine and Environmental Health, Division of Biostatistics, Division of Emergency Medicine, Oregon Health Sciences University, Portland The serum electrolyte panel is one of the most c o m m o n l y performed laboratory tests in the emergency department. The purpose of this study is to validate a previously published decision rule for ordering stat serum electrolytes (Lowe et al, 1987) and to evaluate other predictors of a clinically significant electrolyte abnormality (CSEA) in our study population (emergency patients _>55 years old). A researcher stationed in the ED interviewed the treating physician in a total of 1,810 patient encounters. Extensive follow-up was conducted to determine whether the serum electrolyte panel ordered in the ED resulted in a CSEA and if those patients who did not have the test ordered on the index visit had a subsequent physician encounter (_<14 days) in w h i c h a CSEA was found. Seven hundred ninty-seven patients had electrolytes ordered on the index visit. One hundred twenty-four showed a CSEA (frequency = 15.6 %). The sensitivity and specificity of Lowe's criteria for predicting CSEAs were calculated-sensitivity, .94 {95 % CI = .88 -.97); specificity, .09 (95 % CI = .07-. 11 ). Of the 1,013 patients who did not have a serum electrolyte panel on the index visit, six were found to have a CSEA at a subsequent physician encounter. Lowe's criteria predicted all of these. The relationship between the frequency of CSEA and the reason the test was ordered were analyzed using the chi-square test. Logistic regression analysis was performed to determine which clinical features were independently and significantly predictive of CSEA. The most c o m m o n reason given for ordering electrolytes is tO screen for an unexpected abnormality. The frequency of CSEA for this group was .11 compared with .30 if the physician ordered the test to confirm a suspected abnormality and .03 if the test was ordered by the nurse to expedite patient care. These differences are significant (P < .001}. In particular, emergency physicians who do not suspect CSEA is present and emergency nurses who draw blood prior to physician evaluation may find that Lowe's criteria improve decision making. They should also be aware that elderly patients with a history of renal disease, alcoholism, and impaired ability to c o m m u n i c a t e may be at increased risk for CSEA.
22 Symptom Severity in Acute Myocardial Infarction and its Effect on Patient Delay and Use of 911 MT Ho, MS Eisenberg, S Schaeffer, S Damon, P Litwin, MP Larson/Center for Evaluation of Emergency Medical Services, King County Department of Health, Emergency Medical Services Division; Department of Medicine, University of Washington, Seattle We studied whether symptom severity is predictive of acute myocardial infarction (AMI) and how it affects patient delay in
Annals of Emergency Medicine
439/159
18 Evaluation of the Tilt Test in an Adult Emergency Department Population MA Levitt, M Lieberman, B Lopez, M Sutton/Thomas Jefferson University Hospital, Philadelphia, Pennsylvania Patients presenting to an urban emergency department with complaints suggestive of dehydration and/or blood loss were entered into a study to evaluate the "tilt test" in an adult ED population. As part of their evaluation, changes in heart rate and blood pressure from lying to standing were obtained in a standardized fashion. Body dehydration percent was calculated for each patient w i t h previously published calculations using measured serum osmolality and body weight. Internal or external bleeding was recorded if present. Mean dehydration percentage for this sample population (202) was 3.72 + 2.9. This sample was subdivided into those patients w i t h a diagnosis of blood loss (group 1) and those patients w i t h a diagnosis of dehydration (group 2). Mean dehydration percent for group 1 (36) was 2.73 ± 2.38 and group 2 (166) was 3.94 _+2.97 (P = .0226). Multiple A N O V A testing revealed syncope (P = .037) and lack of axillary sweat (P = .026) to be significantly correlated w i t h dehydration percentage. Symptomatic response to the tilt test was nonsignificant (P = .93). A forward stepwise linear regression model was constructed for the continuous variables {age, change in heart rate [HR], change in systolic pressure [SBP], and change in diastolic pressure [DP]) measured against dehydration percentage. In the whole sample and in group 2, the models found change in HR (P = .0165) and age (P = .0047) to demonstrate a true association with dehydration percentage. None of these variables were significant in the group 1 model. The authors conclude that in orthostatic m e a s u r e m e n t only HR and age have a true association w i t h level of dehydration. However, the a m o u n t of variation in dehydration percentage explained by HR and age is not clinically useful. These m e a s u r e m e n t s demonstrate no association with blood loss. It appears that there i s too m u c h individual variation in a patient's orthostatic response to dehydration and blood loss to determine degree or presence of dehydration or blood loss.
19 Probability of Appendicitis Before and After Observation LG Graft, MJ Radford, C Werne/New Britain General Hospital, New Britain, Connecticut; University of Connecticut Health Center, Farmington The effect of observation on the probability of appendicitis was examined retrospectively in 2 5 2 consecutive patients w i t h abdominal pain Who underwent short-term observation (10.4+ 1.7 hours) prior to the decision to operate. Alvarado.'s scoring system was used to assign a probability of appendicitis to each patient before and after observation. Mean score of patients w i t h appendicitis increased following observation from 6.8 + 0.6 to 7.8 ± 0.5 (P < .01 ), corresponding to a change in probability of appendicitis from 35% to 55%, Mean score of patients w i t h o u t appendicitis decreased from 3.8 ± 0.3 to 1.6 ± .02 (P < .01 ), corresponding to a change in probability from 8% to 3%. Following observation, the difference between m e a n scores of patients w i t h and w i t h o u t appendicitis increased from 2.6 ± 0.6 to 6.2 + .05 (P < .01). Two-by-two contingency table analysis showed that observation improved m e a n accuracy from 65% to 85% (P < .01 ), m e a n probability of diagnosis (positive predictive value)from 70% to 80% (P < .01 ), m e a n specificity from 65% to 86% (P < .01), and m e a n sensitivity from 70% to 80% (NS). By incorporating change in score following observation as a function of preobservation score, sensitivity further increased from 80% to 93 % (P < .01 ), and patients w i t h appendicitis could be separated from those without. In this group of patients with an initial intermediate probability of having appendicitis, observation improved the ability to distinguish patients w i t h and w i t h o u t appendicitis.
20 Threatened Abortion: A Prospective Study of Predictors of Outcome in an Emergency Department Population 18:4 April 1989
J Abbott, M Zaccardi, SR Lowenstein/Department of Surgery, Division of Emergency Medicine and Trauma, Emergency Medicine Clinical Research Center, University of Colorado Health Sciences Center, Denver Although threatened abortion is a c o m m o n problem in the emergency department, no prospective studies in an ED setting have been reported. We examined prospectively the presentation, clinical course, and outcome of 75 consecutive threatened abortion patients in our urban teaching hospital. All patients were in the first half of pregnancy and had vaginal bleeding, a closed cervix, and a positive pregnancy test. While a 50% rate of fetal loss is often quoted for threatened abortion patients, almost three quarters (72%) of our patients had fetal demise; only 28% had a good outcome (pregnancy viable at 20 weeks). Two fetal demises were ectopic. Obstetric history, race, maternal age, hematocrit, vital signs, presence and duration of cramps, presence of clots or abdominal tenderness on examination, and duration of bleeding were not helpful in predicting outcome. The time since last menstrual period was helpful: average time was 90 ± 8 days for good outcome patients versus 64 + 3 days for patients w i t h fetal loss (P = .008). Also, patients w i t h active bleeding were more likely to suffer fetal loss (RR = 2.3, P = .03}. The presence of fetal heart activity by ultrasound was a strong predictor of good outcome (P < .001). Also, a quantitative h u m a n chorionic gonadotropin (HCG) level < 6,500 m I U / m L (P < .001) and the absence of a gestational sac by uhrasound (P < .001) were strong predictors of bad outcome. For patients w i t h an H C G > 6,500 m I U / m L and no fetal heart activity, the chance of a good outcome was only one in five. All patients w i t h an H C G < 6,500 m I U / m L had fetal demise.
21 Predictors of Electrolyte Abnormalities in Elderly Patients BM Singal, JR Hedges, PA Succop/Departments of Emergency Medicine and Environmental Health, Division of Biostatistics, Division of Emergency Medicine, Oregon Health Sciences University, Portland The serum electrolyte panel is one of the most c o m m o n l y performed laboratory tests in the emergency department. The purpose of this study is to validate a previously published decision rule for ordering stat serum electrolytes (Lowe et al, 1987) and to evaluate other predictors of a clinically significant electrolyte abnormality (CSEA) in our study population (emergency patients _>55 years old). A researcher stationed in the ED interviewed the treating physician in a total of 1,810 patient encounters. Extensive follow-up was conducted to determine whether the serum electrolyte panel ordered in the ED resulted in a CSEA and if those patients who did not have the test ordered on the index visit had a subsequent physician encounter (_<14 days) in w h i c h a CSEA was found. Seven hundred ninty-seven patients had electrolytes ordered on the index visit. One hundred twenty-four showed a CSEA (frequency = 15.6 %). The sensitivity and specificity of Lowe's criteria for predicting CSEAs were calculated-sensitivity, .94 {95 % CI = .88 -.97); specificity, .09 (95 % CI = .07-. 11 ). Of the 1,013 patients who did not have a serum electrolyte panel on the index visit, six were found to have a CSEA at a subsequent physician encounter. Lowe's criteria predicted all of these. The relationship between the frequency of CSEA and the reason the test was ordered were analyzed using the chi-square test. Logistic regression analysis was performed to determine which clinical features were independently and significantly predictive of CSEA. The most c o m m o n reason given for ordering electrolytes is tO screen for an unexpected abnormality. The frequency of CSEA for this group was .11 compared with .30 if the physician ordered the test to confirm a suspected abnormality and .03 if the test was ordered by the nurse to expedite patient care. These differences are significant (P < .001}. In particular, emergency physicians who do not suspect CSEA is present and emergency nurses who draw blood prior to physician evaluation may find that Lowe's criteria improve decision making. They should also be aware that elderly patients with a history of renal disease, alcoholism, and impaired ability to c o m m u n i c a t e may be at increased risk for CSEA.
22 Symptom Severity in Acute Myocardial Infarction and its Effect on Patient Delay and Use of 911 MT Ho, MS Eisenberg, S Schaeffer, S Damon, P Litwin, MP Larson/Center for Evaluation of Emergency Medical Services, King County Department of Health, Emergency Medical Services Division; Department of Medicine, University of Washington, Seattle We studied whether symptom severity is predictive of acute myocardial infarction (AMI) and how it affects patient delay in
Annals of Emergency Medicine
439/159