Predicting major hemorrhage in patient with pelvic fracture J Trauma. 2006;61:346~352 Int. 林鼎博

Abstract

Probability of major hemorrhage can be estimated from initial pelvic radiograph, pulse, and hematocrit. 1.Retrospective cohort study 2.Collect subject with pelvic fracture from blunt force mechanism at a single level one trauma center during 4.3 year. 3.Logistic regression was used to formulate a clinical prediction rule. 1.Eligible subjects  627 of 783 patients 2.Hct < 30 HR > 130/min Displaced obturator ring fracture Pubic symphyseal wide diastasis Abstract 1.Pelvic fracture can be an important source of major hemorrhage. 2.No reliable noninvasive method exists for predicting the hemorrhage. 3.To develop a clinical prediction rule to identify the high risk of major hemorrhage.

Background

Background (1) Pelvic fracture is a major source of mortality in high energy trauma. Mortality rate = 10~26% May be potentially life threatening arterial hemorrhage in 5~20% of patients. Angiography with embolization is considered to be an effective treatment for arterial hemorrhage. Knowing which pelvic fracture patients are likely to have serious arterial hemorrhage is important.

Background (2) There have been numerous previous investigation ： Young-Burgess classification scheme ：  Classify fracture patterns based on mechanism of injury and direction of causative force  Association have been identified between posterior and shear-force fracture and arterial hemorrhage. No clinical prediction rule has been proposed.

Background (3) The objective of this study is to develop a clinical prediction rule to identify subjects at high risk of pelvic arterial hemorrhage. Rule would be applicable at initial presentation of the trauma patient, before CT and angiography.

Method

Method (1) Retrospective cohort study At a single urban Level I trauma center Consisting of all nonpenetrating trauma victims that sustained fracture of the pelvis. Fracture was visible on initial resuscitation area AP portable pelvic radiograph. During the 4.3 year period from January 1, 1997 to April 30, 2001

Method (2) Exclusion rule ：  Initially evaluated at a different medical center and transferred  Subjects who died before performance of pelvic radiography. Individuals collecting data on potential predictors were blinded to outcomes and individuals assessing outcomes were blinded to potential predictors.

Method (3) Ascertainment of potential predictors ：  Age, gender, mechanism of injury, pulse, and blood pressure, and laboratory values were available at medical record notes.  X-ray was interpreted by a board certified radiologist with extensive experience in emergency radiology  Record location and displacement of fracture and joint diastasis in the pelvis.  Interobserver agreement between radiologists was determined by independent reading of 10% of the images and calculation of the kappa statistic for agreement. ( is useful )

Method (4) Ascertainment of major hemorrhage ：  arterial extravasation on angiography  high volume pelvic hematoma on CT scan ( >600ml )  high transfusion requirement in the absence of other source of major hemorrhage. ( >6U )

Method (5) Bivariate logistic regression was used to identify those clinical and radiographic factors associated with major pelvic hemorrhage (exclude kappa < 0.4). Multiple logistic regression models were constructed to determine which potential predictors were important. Perform modeling with different transformation of the predictive variables and different interaction terms with a predictor variable and with age.

Result

(20%)

61/% were men Average age were 37.4 y/o Most common mechanism was motor vehicle crash (52%) The Abbreviated Injury Scale were higher in the major pelvic hemorrhage group. Most pelvic fracture subjects had some evidence of hemodynamic compromise.  tachycardia (HR >100 in 76%)  decreased hematocrit (<30 in 34%)  hypotension (sBP < 90mmHg in 22%)

The most common injury locations were the obturator rings (71%) Injuries displaced more than 1 cm were present in 256 (41%)

Q ： A patient with a displaced (>1cm) obturator ring fracture, Hct = 25% HR = 142 /min

Discussion

Discussion (1) A major strength of this prediction rule is reliance on both patient physiology and injury anatomy. Injury locations are a relatively straight- forward assessment of obturator ring fracture and pubis symphysis diastasis.

Discussion (2) 3~4 分： Angiography and embolization may parallel or supercede other interventions including laparotomy. 2 分： Angiography is the first line intervention in patients without obvious major intra-abdominal or intra-thoracic bleeding. 1 分： Angiography should only be considered after other relevant diagnostic tests have been performed, and only if hemodynamic instability worsens or persists. 0 分： Angiography is not indicated unless other interventions aimed at addressing hemodynamic instability have failed.

Discussion (3) We found little association between age and pelvic fracture related hemorrhage. This is in contradistinction to a recent article by Kimbrell.

Discussion (4) Limitation ：  Data developed on a specific patient population  retrospective  Need a gold standard test to determine whether they have major pelvic hemorrhage.  Pelvic radiographs were often technically limited by the ongoing resuscitation efforts.

Discussion (5) Anterior injury locations were more important in predicting major hemorrhage than injuries in the posterior pelvis. This is counterintuitive, as the major structural integrity in the pelvis is provided by the posterior osseous and ligamentous structures. To be useful, a clinical decision rule must be both predictive and reliable. Our data indicate that evaluation of the posterior pelvis on trauma radiographs is not sufficiently reliable.

Discussion (6) This clinical prediction rule achieves neither perfect sensitivity nor perfect specificity. High sensitivity, low specificity   把 p’t 都抓去做 angio  However, there are also potential adverse consequences to the patients with angiography and embolization. Low sensitivity, high specificity  更不好 The use of two or more predictors as a criterion provides a compromise between sensitivity (75%) and specificity (83%)

Summary

HR >= 130 Hct <= 30 diastasis of the pubic symphysis >= 1 cm obturator ring fracture displaced >= 1 cm Number of predictors ： 0  1.6% 1  14% 2  46% 3.4  66%

Thx for your attention!

Abbreviations: APC = anteroposterior compression; CM = combination; LC = lateral compression; SI = sacroiliac; VS = vertical shear. Table Injury Classification Keys According to the Young System Categor y Distinguishing Characteristics LCTransverse fracture of pubic rami, ipsilateral or contralateral to posterior injury I—Sacral compression on side of impact II—Crescent (iliac wing) fracture on side of impact III—LC-1 or LC-II injury on side of impact; contralateral open-book (APC) injury APCSymphyseal diastasis and/or longitudinal rami fractures I—Slight widening of pubic symphysis and/or anterior SI joint; stretched but intact anterior SI, sacrotuberous, and sacrospinous ligaments; intact posterior SI ligaments II—Widened anterior SI joint; disrupted anterior SI, sacrotuberous, and sacrospinous ligaments; intact posterior SI ligaments III—Complete SI joint disruption with lateral displacement; disrupted anterior SI, sacrotuberous, and sacrospinous ligaments; disrupted posterior SI ligaments VSSymphyseal diastasis or vertical displacement anteriorly and posteriorly, usually through SI joint, occasionally through the iliac wing and/or sacrum CMCombination of other injury patterns, LC/VS being the most common