Trauma
Performance of abdominal ultrasonography in blunt trauma patients with out-of-hospital or emergency department hypotension

https://doi.org/10.1016/j.annemergmed.2003.09.011Get rights and content

Abstract

Study objectives

We determine the test performance of abdominal ultrasonography for detecting hemoperitoneum in blunt trauma patients with out-of-hospital or emergency department (ED) hypotension.

Methods

We reviewed the medical records of all blunt trauma patients hospitalized at a Level I trauma center. Patients were included if they were older than 6 years and had out-of-hospital or ED hypotension (systolic blood pressure ≤90 mm Hg) and underwent ED ultrasonography. The initial interpretation of the abdominal ultrasonography was recorded, including the presence or absence of intraperitoneal fluid and the specific location of such fluid. Presence or absence of intra-abdominal injury was determined by abdominal computed tomography scan, laparotomy, or clinical follow-up.

Results

Four hundred forty-seven patients with a mean age of 36.0±17.5 years were enrolled. One hundred forty-eight (33%) patients had intra-abdominal injuries, and 116 (78%) of these patients had hemoperitoneum. Abdominal ultrasonography had the following test performance for detecting patients with intra-abdominal injury and hemoperitoneum: sensitivity 92/116 (79%; 95% confidence interval [CI] 71% to 86%), specificity 316/331 (95%; 95% CI 93% to 97%), positive predictive value 92/107 (86%; 95% CI 78% to 92%), and negative predictive value 316/340 (93%; 95% CI 90% to 95%). The positive likelihood ratio was 15.8, and the negative likelihood ratio was 0.22. One hundred five (91%) of the 116 patients with intra-abdominal injuries and hemoperitoneum underwent a therapeutic laparotomy. Abdominal ultrasonography demonstrated intraperitoneal fluid in 87 (sensitivity 83%; 95% CI 74% to 90%) of these 105 patients.

Conclusion

Of patients with out-of-hospital or ED hypotension, abdominal ultrasonography identifies most patients with hemoperitoneum and intra-abdominal injuries. Hypotensive patients with negative abdominal ultrasonography results, however, must be further evaluated for sources of their hypotension, including additional abdominal evaluation, once they are hemodynamically stabilized.

Introduction

Patients with hypotension after a blunt traumatic event require rapid evaluation to identify and treat the source or sources of hypotension. Immediate identification of hemorrhagic sources of hypotension is a priority during the initial resuscitation because hypotension caused by hemorrhage requires urgent volume replacement and specific therapy to cease further hemorrhage. External sources of hemorrhage are readily identified on physical examination, and hemorrhage from pelvic fractures or into the thoracic cavity may be initially assessed with pelvic and chest radiography. Because of the unreliability of the abdominal examination and limitations of acceptable diagnostic testing in the hemodynamically unstable patient, intra-abdominal hemorrhage has traditionally been a challenge for the clinician to identify.

Abdominal computed tomography (CT), although excellent for the diagnosis of intra-abdominal injuries and intraperitoneal fluid, is contraindicated in hemodynamically unstable patients. Diagnostic peritoneal lavage requires time, is invasive, and may not be appropriate in alert patients. The development of abdominal ultrasonography has provided clinicians with a diagnostic technique for abdominal evaluation that is theoretically useful in the unstable patient. Abdominal ultrasonography allows physicians a rapid method for evaluating the abdomen for intraperitoneal fluid. Most clinically significant intra-abdominal injuries, including those resulting in patient hypotension, are associated with hemoperitoneum.1, 2 The focused abdominal sonography for trauma examination may be performed rapidly in the emergency department (ED) during the patient's initial evaluation. It has a high sensitivity for detecting intraperitoneal fluid and a high negative predictive value for predicting laparotomy.3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 These qualities make ultrasonography a useful diagnostic modality for evaluating patients with hypotension caused by intra-abdominal hemorrhage. Limited previous evidence suggests that ultrasonography has an excellent test performance in this cohort of patients.15, 16, 17

Capsule Summary

What is already known on this topic

Emergency bedside ultrasonography is frequently used in trauma patients, but its sensitivity for detecting hemoperitoneum has not been clarified.

What question this study addressed

This work tests the hypothesis that emergency bedside ultrasonography will be sensitive enough to detect the presence of hemoperitoneum in all blunt trauma patients who have been hypotensive either in the out-of-hospital setting or emergency department.

What this study adds to our knowledge

Emergency bedside ultrasonography detected hemoperitoneum in only 92 (sensitivity 79%; 95% CI 71% to 86%) of 116 patients with the condition present; however, it correctly ruled out the presence of hemoperitoneum in 316 (specificity 95%; 95% CI 93% to 97%) other patients who did not have hemoperitoneum.

How this might change clinical practice

The authors conclude that emergency ultrasonography cannot be relied on alone to detect the presence of hemoperitoneum in all blunt trauma patients.

The objective of this study was to determine the performance of abdominal ultrasonography for detecting hemoperitoneum in blunt trauma patients with out-of-hospital or ED hypotension. We hypothesize that ultrasonography will have excellent test characteristics (sensitivity and specificity) in blunt trauma patients with out-of-hospital or ED hypotension.

Section snippets

Study design

This study was a retrospective review of the medical records of all hospitalized blunt trauma patients from July 1, 1996, to January 31, 2001. The study was approved by the Human Subjects Research Committee at our institution.

Setting and selection of participants

The study was conducted at an urban Level I trauma center. The ED has an annual census of 65,000 patient visits, of which 12% of visits are after traumatic events.

Hospitalized blunt trauma patients were included if they were older than 6 years and had out-of-hospital or ED

Characteristics of study subjects

A total of 12,119 admitted patients' records were reviewed, and 717 (5.9%) patients had out-of-hospital or ED hypotension (Figure). The 447 (62%) patients who underwent abdominal ultrasonography compose the study population. The mean age of the 447 patient study population was 36.0±17.5 years, and 254 (57%) were men. Two hundred sixty-two (59%) patients were identified with ED hypotension. Two hundred seventy-five (61%) patients had out-of-hospital hypotension. Ninety (20%) patients had ED and

Limitations

This study was limited by its retrospective design. Incomplete documentation may exist in the patients' medical records. Most important, this methodology limits the ability to determine the effect of ultrasonography on clinical decisionmaking at patient resuscitation. Future prospective studies could best answer this question. We were unable to truly assess the presence or absence of intraperitoneal fluid at initial abdominal ultrasonography. The determination of intraperitoneal fluid was made

Discussion

We found that abdominal ultrasonography identified the majority of hypotensive patients with hemoperitoneum caused by intra-abdominal injuries, as well as most patients who underwent therapeutic laparotomy for these injuries. However, ultrasonography failed to identify intraperitoneal fluid in an important percentage of patients with hemoperitoneum, including several patients who required urgent laparotomy. The effect of abdominal ultrasonography in the hypotensive trauma patient is best

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    Author contributions: JFH and DH conceived the study. JFH developed its design. JFH, DH, and FDB acquired the data; DH managed the data; and JFH analyzed and interpreted the data. JFH and FDB drafted the manuscript. All authors take responsibility for the paper as a whole.

    Presented at the American College of Emergency Physicians Research Forum, Seattle, WA, October 2002.

    The authors report this study did not receive any outside funding or support.

    Reprints not available from the authors.

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