Optimal blood ordering for emergency department patients

ORIGINAL CONTRIBUTION

Optimal Blood Ordering for Emergency Department Patients John R. Clarke, MD Steven J. Davidson, MD Garrett E. Bergman, MD Nancy L. Geller, PhD Philadelphia, Pennsylvania

A lack of documented criteria for determining which emergency patients should have blood crossmatched for possible transfusion led us to review the records of all patients for whom blood was crossmatched in the emergency unit of our hospital in 1977. Of 378 patients who had blood crossmatched for 1,230 units, only 105 (28%) received blood transfusions (331 units total). Variables showing relationship to transfusion of blood were consolidated into four criteria: 1) shock; 2) hematocrit less than 30%; 3) observed blood loss of at least 500 ml or grossly visible gastrointestinal bleeding; and 4) emergency surgery with anticipated blood loss. Application of these criteria identified 55% of patients who did not receive transfusions and 41% of units unnecessarily crossmatched, while failing to identify only three patients receiving single-unit transfusions. Use of the criteria would have reduced the crossmatch/transfusion ration from 3.7:1 to 2.6:1. Clark JR, Davidson SJ, Bergman GE, GellerNL: Optimal blood ordering for emergency department patients, Ann Emerg Med 9:2-6, January 1980, blood ordering, emergency; criteria I NTRODUCTION

C r i t e r i a for a p p r o p r i a t e u t i l i z a t i o n of b a n k e d blood are necessary to minimize waste of this critical resource. C r i t e r i a h a v e been developed to predict how much, if any, blood should o p t i m a l l y be crossmatched for elective surgical procedures. 1-4 However, no c r i t e r i a existed as to when or how much blood should be crossmatched for p a t i e n t s in the e m e r g e n c y d e p a r t m e n t . Because the crossmatch/transfusion ratio (C/T ratio) in our emergency dep a r t m e n t (3.7:1) was considered h i g h e r t h a n our 2.5:1 overall hospital ratio, w e p e r f o r m e d a r e t r o s p e c t i v e r e v i e w of all e m e r g e n c y p a t i e n t s who h a d blood crossmatched for t r a n s f u s i o n during 1977. The study enabled us to d e t e r m i n e the factors r e l a t i n g to t h e likelihood of t r a n s f u s i o n and to develop criteria for crossmatching blood in the e m e r g e n c y d e p a r t m e n t . MATERIALS AND METHODS The Hospital of t h e Medical College of P e n n s y l v a n i a is a 330-bed i n s t i t u t i o n w i t h a residency t r a i n i n g p r o g r a m in e m e r g e n c y medicine. There were 32,704 p a t i e n t visits to the e m e r g e n c y d e p a r t m e n t in 1977, a large proportion of which were due to p e n e t r a t i n g and v e h i c u l a r t r a u m a , l a t e - s t a g e diseases (including alcoholism), and u n a t t e n d e d pregnancies. M a n a g e m e n t of patients, including From the Departments of Surgery, Pediatrics, and Community and Preventive Medicine, the Section of Emergency Medicine, and the Medical Audit Committee, The Medical College of Pennsylvania, Philadelphia, Pennsylvania. Presented at the University Association for Emergency Medicine Annual Meeting in Orlando, Florida, May 1979. Address for reprints: Steven J. Davidson, MD, Section of Emergency Medicine, The Medical College of Pennsylvania, Philadelphia, Pennsylvania 19129.

9:1 (Jan uary) 1980

Ann

Emerg Med

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requests for t h e c r o s s m a t c h i n g a n d transfusion of blood, is i n i t i a t e d by e m e r g e n c y d e p a r t m e n t r e s i d e n t s in emergency medicine, i n t e r n a l medicine, pediatrics, and surgery. Because it was thought that physicians in the emergency departm e n t s h o u l d be e x p e c t e d o n l y to identify and correct i m m e d i a t e transfusion needs, emergency transfusion needs were defined as t r a n s f u s i o n s given w i t h i n 12 hours of a r r i v a l or w i t h i n t h e f i r s t t w o h o u r s of a n emergency operation, whichever came first. An operation was an e m e r g e n c y i f it t o o k p l a c e w i t h i n e i g h t hours of a r r i v a l . A m a x i m u m of eight units of blood crossmatched per p a t i e n t was imposed for the purpose of analysis. There were no instances in which application of these restrictions a p p e a r e d u n r e a s o n a b l e . C h a r t s of all p a t i e n t s who h a d blood crossmatched in the e m e r g e n c y d e p a r t m e n t in 1977 were reviewed. W h e n type-specific blood was transfused, crossmatching was done after t r a n s f u s i o n . A n a d d i t i o n a l 333 pat i e n t s had blood d r a w n for blood-typing only Ctype and hold") and were not studied. Twelve variables were reviewed for t h e i r relationship to the need for

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Number of Patients/Units

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Fig. 2. Comparison of number of patients receiving transfusions and units of blood transfused by units transfused per patient.

t r a n s f u s i o n , t h e n u m b e r of u n i t s t r a n s f u s e d , a n d t h e e m e r g e n c y release of type-specific blood. The varia b l e s were: c h i e f c o m p l a i n t on arr i v a l in the emergency d e p a r t m e n t , d u r a t i o n of bleeding, pulse rate, systolic blood p r e s s u r e (SBP), results of the t i l t test, site of bleeding, a m o u n t of b l e e d i n g , h e m a t o c r i t , w o r k i n g diagnosis, g e n e r a l t y p e of problem, need for e m e r g e n c y o p e r a t i o n , a n d e s t i m a t e d blood loss a t o p e r a t i o n . The t i l t test was considered positive if t h e r e w a s a 20-torr drop in systolic blood p r e s s u r e or a 20 b e a t / m i n increase in pulse rate when the p a t i e n t was t r a n s f e r r e d to the u p r i g h t position. G e n e r a l types of problems were gastrointestinal bleeding, vaginal bleeding, t r a u m a , a n d miscellaneous. Trauma was further divided into missile wounds, stab wounds, and b l u n t t r a u m a . A n e m e r g e n c y operat i o n was d e f i n e d in r e t r o s p e c t , as was o p e r a t i v e blood loss. An a t t e m p t was m a d e retrospect i v e l y to d e t e r m i n e the presence of shock in those p a t i e n t s not obviously h y p o t e n s i v e . In a d d i t i o n to a n abn o r m a l l y low systolic blood p r e s s u r e (SBP < 9 0 torr), any one of the following c r i t e r i a was used to categorize p a t i e n t s as b e i n g in shock: 1)

Ann E m e r g M e d

SBP < 100 tqrr w i t h p u l s e r a t e > 120 b e a t s / m i n unless the t i l t test was recorded as negative; 2) SBP < 110 t o r r with pulse r a t e > 140 beats/rain u n l e s s the tilt test was recorded as negative; or 3) positive t i l t test. S t a t i s t i c a l a n a l y s i s of t h e data w a s by m u l t i p l e regression analysis or chi-square analysis.

RESULTS Profile of Blood Usage There were 1,230 units of blood crossmatched for 378 p a t i e n t s (mean 3.3 units/patient). W i t h i n the guidelines of the investigation, 703 uni~ of blood were c r o s s m a t c h e d for the 273 p a t i e n t s (72%) who did not re. ceive t r a n s f u s i o n s (mean 2.6 units1 p a t i e n t ) a n d 537 u n i t s .were cross. m a t c h e d for the 105 p a t i e n t s (28%) who received transfusions ( m e a n 5.0 u n i t s / p a t i e n t ) . Of these, 331 units were t r a n s f u s e d (3.2 u n i t s / p a t i e n t re. ceiving transfusions) for a C/T ratio of 3.7:1 (Figure 1). A m o n g t h e p a t i e n t s receiving t r a n s f u s i o n s , 29 p a t i e n t s (28%) re. ceived s i n g l e - u n i t t r a n s f u s i o n s . Of these, 12 received more transfusions b e y o n d t h e p e r i o d s t u d i e d . There •w e r e 17 t r u e s i n g l e - u n i t transfu.

9:1 (January) 1980

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Hours Between Arrival and Transfusion of Blood Fig. 3. Cumulative distribution of initial transfusions by time. si0ns; 13 were considered a p p r o p r i a t e by members of the h o s p i t a l ' s blood utilization committee and four were of i n d e t e r m i n a t e v a l u e . E i g h t patients (8%) u l t i m a t e l y received more than the original eight units crossmatched, t h e m a x i m u m b e i n g 31 units of blood. The 25 p a t i e n t s (24%) who received more t h a n four units of blood accounted for 52% of the blood transfused (Figure 2). Twenty p a t i e n t s received typespecific blood d u r i n g t h e i r s t a y in the emergency d e p a r t m e n t or o p e r a t i n g room or d u r i n g t h e i r first h o s p i t a l day, but o n l y 11 p a t i e n t s (10% of those t r a n s f u s e d ) r e c e i v e d t r a n s f u sions of type-specific blood w i t h i n the first 30 m i n u t e s of a r r i v a l in t h e emergency d e p a r t m e n t . These 11 patients received 36 units of type-specific blood (median 2 units, m e a n 3.3 u n i t s / p a t i e n t ) . T h r e e of t h e s e patients l a t e r received more t h a n eight units of blood ( m a x i m u m 22 units), including one who received all 12 of his units as type-specific blood. The time between the a r r i v a l of the p a t i e n t a n d t h e r e l e a s e of t h e first unit of blood for transfusion varied from 20 m i n u t e s to 11.5 hours, with a m e d i a n of 3 hours (Figure 3).' Excluding t y p e - s p e c i f i c blood, t h e time of r e l e a s e of t h e f i r s t crossmatched u n i t r a n g e d from 30 minutes to 11.5 hours, with 50% of the patients r e c e i v i n g t h e i r f i r s t u n i t

9:1 (January) 1980

w i t h i n 3 hours of a r r i v a l and 75% w i t h i n 5 hours. No c o r r e l a t i o n was f o u n d between C/T ratios and the month of the academic year, indicating that t h e d e v e l o p m e n t of clinical experience d u r i n g the residency h a d little r e l a t i o n to u t i l i z a t i o n of blood in the emergency department.

Development of Criteria for Crossmatching U s i n g p a t i e n t s for w h o m complete d a t a were a v a i l a b l e (n = 344), the occurrence of blood t r a n s f u s i o n w a s c o r r e l a t e d by m u l t i p l e regression a n a l y s i s with several variables. In d e c r e a s i n g order, t h e v a r i a b l e s which h a d s e p a r a t e predictive values for the likelihood of transfusion were hematocrit, operative blood loss, g e n e r a l t y p e of problem, and systolic blood p r e s s u r e . P a t i e n t s with overt g a s t r o i n t e s t i n a l (GI) b l e e d i n g were l i k e l y to receive transfusions; those w i t h v a g i n a l b l e e d i n g , as a r u l e , w e r e not. D e s p i t e t h e level of sign i f i c a n c e for a m u l t i p l e r e g r e s s i o n a n a l y s i s (P < 0.001), only 37% of the v a r i a n c e in the likelihood of t r a n s fusion was e x p l a i n e d by the model (R 2 = 0.37). Because of a s m a l l e r n u m b e r of p a t i e n t s w i t h t h i s i n f o r m a t i o n recorded, the d u r a t i o n of bleeding and t h e a m o u n t of blood loss o b s e r v e d w e r e s e p a r a t e l y c o m p a r e d to t h e

Ann Emerg Med

likelihood of t r a n s f u s i o n u s i n g chi: square analyses. No dependence was found between t h e d u r a t i o n of bleedi n g and the occurrence of transfusion (n = 297, P = 0.8). The occurrence of t r a n s f u s i o n was h i g h l y dependent on observed blood loss (n = 174, P < 0.001). B a s e d on t h e v a r i a b l e s w h i c h had a significant relationship with t h e l i k e l i h o o d of t r a n s f u s i o n , four simple criteria were constructed for v a l i d a t i n g c o n s i d e r a t i o n s to crossm a t c h blood for p a t i e n t s in the emergency d e p a r t m e n t . The c r i t e r i a ~)e: 1) shock; 2) h e m a t o c r i t less t h a n 30%; 3) observed blood loss of at l e a s t 500 ml or grossly visible GI bleeding; and 4) e m e r g e n c y operation with anticip a t e d blood loss. A m o n g the 378 p a t i e n t s considered p o t e n t i a l candidates for transfusion in the e m e r g e n c y d e p a r t m e n t , the s t r a t e g y employing all four crit e r i a gave the best result. V a l i d a t i o n by at least one of the criteria prior to c r o s s m a t c h i n g blood would have res u l t e d in a 55% r e d u c t i o n in t h e n u m b e r of p a t i e n t s crossmatched b u t not t r a n s f u s e d (151 of 273). This reduction would h a v e resulted in saving from u n n e c e s s a r y crossmatching 366 units of blood, a 41% reduction in the n u m b e r of units used. The C/T ratio would have been reduced from 3.7:1 to 2.6:1 (Table 1). Only three of the patients (3%) who received transfusions would have been overlooked u s i n g t h e c r i t e r i a . I n all t h r e e ins t a n c e s , t h e p a t i e n t s r e c e i v e d sin: g l e - u n i t t r a n s f u s i o n s , a l t h o u g h all t h e s e t r a n s f u s i o n s a p p e a r e d approp r i a t e . T h e r e were no i n s t a n c e s in which the criteria failed to identify p a t i e n t s n e e d i n g transfusions of multiple units. In contrast, at least one p a t i e n t was identified as h a v i n g bel a t e d clinical recognition of w h a t was a two-unit transfusion r e q u i r e m e n t .

Criteria for Unit Ordering The criteria for proceeding with t h e c r o s s m a t c h i n g of blood b e c a m e the basis for f u r t h e r correlation with the n u m b e r of units of blood t r a n s fused. W i t h i n the group 6f p a t i e n t s receiving transfusions for whom all d a t a were a v a i l a b l e (n = 48), multiple regression analysis was used to correlate the n u m b e r of units t r a n s : fused with the varihbles. Not unexpectedly, operative blood loss was the most significant v a r i a b l e associated with the n u m b e r of units transfused, followed by d e g r e e of h y p o t e n s i o n . The r e l a t i o n s h i p 'was roughly 1 u n i t of blood t r a n s f u s e d for each 20-torr decrease from n o r m a l SBP. Gastroin-

4711

t e s t i n a l b l e e d i n g was also a signifi c a n t v a r i a b l e . No d e p e n d e n c e was found between the n u m b e r of u n i t s t r a n s f u s e d and e i t h e r observed blood loss, i n d e p e n d e n t of shock, or h e m a tocrit. Again, only 48% of the variance in t h e n u m b e r of u n i t s transfused was explained by m u l t i p l e regression analysis, despite h i g h l y s i g n i f i c a n t F v a l u e s (R 2 = 0.48, P < 0.001). S i n c e t h e n u m b e r of u n i t s of blood t r a n s f u s e d is h i g h l y d e p e n d e n t on o p e r a t i v e blood loss and SBP, the criteria were given the following weights: 1) shock - - 2 units, plus 2 units for each 40-torr decrease from n o r m a l s y s t o l i c blood p r e s s u r e ; 2) h e m a t o c r i t less t h a n 30% - - 2 units; 3) observed blood loss of at l e a s t 500 ml or grossly visible GI bleeding - - 2 units; 4) e m e r g e n c y o p e r a t i o n - - 2 u n i t s for each l i t e r of a n t i c i p a t e d blood loss. Two-unit i n c r e m e n t s , to the m a x i m u m of e i g h t u n i t s crossmatched, were used for simplicity. W h e n a p a t i e n t m e t several of t h e s e c r i t e r i a , it w a s n o t obvious w h e t h e r the values for t h e c r i t e r i a should be additive. Additive, nonadditive, and intermediate strategies were tried. The s t r a t e g y of a d d i n g v a l u e s for each of the c r i t e r i a produced no reduction in the n u m b e r of units unnecessarily crossmatched. The s t r a t e g y of selecting the h i g h e s t single value grossly u n d e r e s t i m a t e d t r a n s f u s i o n needs by a t o t a l of 27 units of blood in 15 patients. The int e r m e d i a t e s t r a t e g y of a d d i n g t h e v a l u e s for shock to the h i g h e s t v a l u e for a n y o t h e r c r i t e r i o n would h a v e s a v e d 30 u n i t s of blood f r o m unnecessary crossmatching, despite the h a n d i c a p of o r d e r i n g i n t w o - u n i t aliquots (Table 2). This s t r a t e g y underestimated transfusion requirem e n t s in seven instances (7% of patients). Among the five u n d e r e s t i m a t e d by a single unit of blood, t h r e e were the single-unit transfusions excluded by the i n i t i a l c r i t e r i a and one was c l i n i c a l l y u n d e r e s t i m a t e d by t h r e e units on first appraisal. The transfusion r e q u i r e m e n t s o f two o t h e r pat i e n t s w e r e u n d e r e s t i m a t e d by a total of e i g h t units of blood u s i n g the criteria (four units each); in the s a m e two p a t i e n t s , t h e t r a n s f u s i o n r e q u i r e m e n t s were clinically underest i m a t e d by seven u n i t s on i n i t i a l app r a i s a l . The o t h e r p a t i e n t i n i t i a l l y receiving inadequate transfusions c l i n i c a l l y also h a d a m u l t i p l e - u n i t shortage. The best s t r a t e g y for predicting t h e n u m b e r of u n i t s to c r o s s m a t c h

12/5

Table 1 APPLICATION OF CRITERIA FOR VALIDATING CROSSMATCHING IN THE EMERGENCY DEPARTMENT

Ideal Correctly identified as not requiring transfusions

No. Patients Actual

By Criteria

273

0

151

0

273

122

105

104

102

Missed single-unit transfusions

0

0

3

Missed multiple-unit transfusions

0

1

0

Blood unnecessarily crossmatched Correctly identified as requiring transfusions

was a p p l i e d to t h o s e 122 p a t i e n t s who met a criterion for crossmatching blood b u t who, in fact, were not transfused. They would have had 348 u n i t s of blood c r o s s m a t c h e d by the c r i t e r i a . C l i n i c a l l y , t h e y h a d 337 units of blood crossmatched. Overall 845 units of blood event u a l l y would h a v e been crossmatched u s i n g t h e v a l u e s a s s i g n e d for t h e c r i t e r i a (C/T r a t i o 2.6:1) c o m p a r e d w i t h 1,230 u n i t s of blood a c t u a l l y crossmatched (C/T ratio 3.7:1), for a savings of 385 units. Of this savings, 366 units (95%) resulted from ident i f y i n g p a t i e n t s w i t h o u t indications for crossmatching, and only 19 units (5%) from p r e d i c t i n g the a p p r o p r i a t e n u m b e r of units to crossmatch. Use of the c r i t e r i a to v a l i d a t e who should h a v e blood crossmatched would in itself r e s u l t in a C/T ratio of 2.6:1.

Patients Receiving Uncrossmatched Blood By i n s p e c t i o n , t h e 11 p a t i e n t s r e c e i v i n g type-specific blood as a n e m e r g e n c y w i t h i n 30 m i n u t e s of arr i v a l were u n i f o r m l y c h a r a c t e r i z e d by obvious shock (SBP< 90 tort) associated with major observed blood loss (including overt GI bleeding) or blood loss a n t i c i p a t e d w i t h e m e r gency operation. While all p a t i e n t s r e q u i r i n g e m e r g e n c y t r a n s f u s i o n of type-specific blood met these criteria, the reverse was not true. There were 23 p a t i e n t s (22% of those transfused) who met the c r i t e r i a but did not req u i r e e m e r g e n c y t r a n s f u s i o n of type-specific blood on a r r i v a l in the emergency department.

DISCUSSION Major a s s u m p t i o n s are i n h e r e n t

Ann E m e r g M e d

in t h e d e v e l o p m e n t of c r i t e r i a fo~ c r o s s m a t c h i n g blood in emergenc) p a t i e n t s from a retrospective review. The obvious a s s u m p t i o n s are t h a t all p a t i e n t s who needed transfusions rec e i v e d t h e m a n d t h a t all patients who r e c e i v e d t r a n s f u s i o n s needed t h e m . P a t i e n t s who d i d n o t have blood c r o s s m a t c h e d were n e v e r in. corporated in the review, but in pat i e n t s who d i d h a v e b l o o d crossm a t c h e d t h e r e were no obvious cases of i n a d e q u a t e or excessive transfusion therapy. Less obvious, b u t m o r e impor. t a n t , clinical considerations for crossm a t c h i n g blood p r e c e d e d applica. tion of the criteria. It is l i k e l y that p a t i e n t s with one or more of the crit e r i a n e v e r had blood crossmatched. This would be expected for patients h y p o t e n s i v e from m y o c a r d i a l infarctions; it would be likely in patients w i t h a n e m i a who d i d n o t have k n o w n diagnoses, symptoms, or other c o n d i t i o n s m a k i n g t r a n s f u s i o n urg e n t , b u t who w e r e p r o p e r l y evalu a t e d to establish a diagnosis prior to t r a n s f u s i o n c o n s i d e r a t i o n s . The c r i t e r i a do not f u n c t i o n as indicat o r s for c r o s s m a t c h i n g blood, but as v a l i d a t i o n c r i t e r i a for situations in which c r o s s m a t c h i n g of blood is c o n s i d e r e d . F o r p a t i e n t s in whom c r o s s m a t c h i n g is c o n s i d e r e d but criteria are not present, blood should not be crossmatched b u t r a t h e r typed and screened for a n t i b o d i e s as reco m m e n d e d by Boral and Henry. 5 The method of developing criteria relied on retrospective information a b o u t e m e r g e n c y o p e r a t i o n s and o p e r a t i v e b l o o d loss, p r e s u m a b l y more accurate t h a n prospective esti. mates. On the o t h e r hand, the crit e r i a were r e q u i r e d to predict transfusion needs a t a single t i m e soon

9:1 (January) 1980

Table 2 CRITERIA FOR NUMBER OF UNITS TO CROSSMATCH APPLIED TO PATIENTS RECEIVING TRANSFUSIONS

Actual

By Criteria

Units of blood crossmatched initially

515

484

Units of blood transfused (including belatedly)

331

331

Units of blood unnecessarily crossmatched

196

166

Number of patients inadequately transfused by initial assessment ( > l - u n i t deficit) Units of blood transfused belatedly

4*

7"

(4)t

(2)*

12

13

*Three patients are common to both groups. tTwo patients are common to both groups.

after the p a t i e n t ' s a r r i v a l , w i t h o u t allowances for subsequent revisions based on t h e c l i n i c a l c o u r s e . T h e use of t w o - u n i t i n c r e m e n t s in criteria to p r e d i c t t r a n s f u s i o n n e e d s was based on a desire for simplicity in developing criteria. These c r i t e r i a were not superior to clinical performance in e s t i m a t i n g t r a n s f u s i o n needs. If clinical requests had been made in two-unit aliquots, however, the criteria would have been m a r k edly superior, s u g g e s t i n g t h e y m i g h t be more accurate in predicting t r a n s fusion needs if the r e q u i r e m e n t for two-unit i n c r e m e n t s were dropped. Although v a r i a b l e s with h i g h l y significant p r e d i c t i v e v a l u e s w e r e identified, much of the v a r i a b i l i t y in transfusion needs was not e x p l a i n e d by the v a r i a b l e s in the m u l t i p l e regression a n a l y s i s (R 2 = 0.37 a n d 0.48). The s t a t i s t i c a l model, however, was not i n t e n d e d to predict transfusion needs, b u t was used to provide direction for the development of simple criteria. The i n t e r n a l l y v a l i d a t e d C/T ratio of 2.6:1 using t h e s e c r i t e r i a was encouraging, for it a p p r o a c h e d C/T ratios for o t h e r a r e a s of blood transfusion, such as e l e c t i v e s u r gery.1 Because t h e c r i t e r i a developed from this retrospective review were validated i n t e r n a l l y , ie, a g a i n s t t h e experience w h i c h g e n e r a t e d t h e m , optimal r e s u l t s should be expected. Although the r e s u l t s were encouraging, t h e c r i t e r i a m u s t be a p p l i e d prospectively to o t h e r s e t s of p a tients, p e r h a p s w i t h o u t s t i p u l a t i o n of cr0ssmatching blood in two-unit increments, to be p r o p e r l y validated. E x a m i n a t i o n of the c r i t e r i a re-

9:1 (January) 1980

veals a g e n e r a l t h e m e of r e p l a c i n g blood deficits. Shock, a n e m i a , a n d observed blood loss indicate existing blood deficits. E m e r g e n c y operations i n d i c a t e a n t i c i p a t e d blood losses. The need to crossmatch blood for p a t i e n t s in t h e e m e r g e n c y d e p a r t m e n t a n d t h e a p p r o p r i a t e n u m b e r of units to c r o s s m a t c h should be b a s e d on rep l a c e m e n t of existing or a n t i c i p a t e d losses. A l t h o u g h s t a t e d e x p l i c i t l y , t h e c r i t e r i a s h o u l d be m o d i f i e d as a p p r o p r i a t e by the e m e r g e n c y physician based on these considerations. Shock should be secondary to hypovolemia. A n e m i a should be symptomatic; a s s o c i a t e d w i t h o t h e r conditions, such as blood loss or p l a n n e d anesthesia; or secondary to a known cause to be considered an a p p r o p r i a t e indication for i m m e d i a t e transfusion needs. Overt GI bleeding is l i k e l y to r e q u i r e transfusion, w h e r e a s v a g i n a l bleeding r a r e l y does. E x t e n s i v e blood loss in t h e e m e r g e n c y d e p a r t m e n t may require additional transfusion needs, although such additional needs are likely to be addressed by the incipient p r e s e n t a t i o n of shock. Blood losses from e m e r g e n c y ope r a t i o n s seem to p a r a l l e l losses from elective operations, with the obvious exception of e m e r g e n c y e x p l o r a t o r y laparotomies, where transfusions are m o r e l i k e l y to be n e e d e d t h a n in elective exploratory laparotomies. In 30 p a t i e n t s u n d e r g o i n g e m e r g e n c y d i l a t i o n and curettage, only one u n i t of blood was t r a n s f u s e d in t h e absence of p r e o p e r a t i v e criteria. ~Anticipated" blood loss justifies extensive crossmatching for p o t e n t i a l vasc u l a r c a t a s t r o p h i e s even w h e n t h e decision, retrospectively, is in error.

Ann Emerg Med

CONCLUSION A m o n g p a t i e n t s considered pot e n t i a l candidates for transfusion in the emergency department, retrospective review of associated factors i n d i c a t e d t h e following c r i t e r i a are associated w i t h transfusion needs: 1) shock; 2) h e m a t o c r i t less t h a n 30%; 3) observed blood loss of at least 500 ml or grossly visible GI bleeding; and 4) emergency operation with anticip a t e d blood loss. V a l i d a t i o n of t h e c r i t e r i a u s i n g the d a t a base which spawned t h e m showed t h a t application of the c r i t e r i a would reduce the n u m b e r of p a t i e n t s c r o s s m a t c h e d u n n e c e s s a r i l y by 55% a n d t h e C/T r a t i o from 3.7:1 to 2.6:1. Only t h r e e s i n g l e - u n i t transfusions (in 105 patients transfused) were missed by these criteria. The n u m b e r of units t r a n s f u s e d was r e l a t e d to the volume of blood loss as i n d i c a t e d by shock and the operative blood loss. Criteri a r e g a r d i n g t h e n u m b e r of u n i t s crossmatched were equal to, b u t not b e t t e r t h a n , clinical j u d g m e n t a n d m a y be useful as a u d i t criteria. Pat i e n t s r e q u i r i n g e m e r g e n c y transfusion of type-specific blood h a d obvious shock with ongoing or anticipated o p e r a t i v e blood losses, a l t h o u g h t h e m a j o r i t y of p a t i e n t s w i t h these criteria were treated with crossm a t c h e d blood a l o n e . C r i t e r i a reg a r d i n g who s h o u l d or s h o u l d n o t h a v e blood c r o s s m a t c h e d a p p e a r to h a v e a m a j o r i m p a c t on i m p r o v i n g use of blood b a n k s e r v i c e s by t h e e m e r g e n c y d e p a r t m e n t . Prospective v a l i d a t i o n is necessary. The authors thank Robert S. Roberts, Traute Bartoloni, and Tony Yeh for their assistance in this project.

REFERENCES 1. Mintz PD, Nordine RB, Henry JB, et al: Expected hemotherapy in elective surgery. N Y S t a t e J M e d 76:532-537, 1976. 2. Friedman BA, Oberman HA, Chadwick AR, et al: The maximum surgical blood order schedule and surgical blood use in the United States. T r a n s f u s i o n 16"380-387, 1976. 3. Henry JB, Mintz P, Webb W: Optimal blood ordering for elective surgery. J A M A 237:451, 1977. 4. Mintz PD, Lauenstein K, Hume J, et al: Expected hemotherapy in elective surgery: A follow-up. J A M A 239:623-625, 1978. 5. Boral LI, Henry JB: The type and screen: A safe alternative and supplement in selected surgical procedures. Transfusion 17:163-168, 1977. 6/13