Importance of evaluating organ parenchyma during screening abdominal ultrasonography after blunt trauma.

OBJECTIVE: To determine the benefit of screening ultrasonography for parenchymal abnormalities as well as free fluid during screening abdominal ultrasonography in patients with blunt trauma. METHODS: A total of 2693 patients with blunt trauma who were triaged to a level 1 trauma center underwent screening abdominal ultrasonography in the resuscitation suite. Examinations were performed by experienced sonographers and included a screen for free intraperitoneal fluid and evaluation of the abdominal organ parenchyma and heart for traumatic injury. Screening ultrasonographic findings were reviewed and compared with findings from autopsy, laparotomy, diagnostic peritoneal lavage, computed tomography, repeated ultrasonography, cystography, and clinical outcome. Imaging studies of all patients with confirmed or suspected injuries were reviewed to identify those in whom parenchymal findings aided diagnosis. RESULTS: One hundred seventy-two patients were found to have evidence of abdominal injury due to blunt trauma on the basis of clinical data, imaging, laparotomy, or autopsy. Forty-four of these patients had no sonographic evidence of hemoperitoneum at the time of initial ultrasonography. Screening ultrasonographic findings were positive for injury in 19 of 44 patients on the basis of parenchymal findings or small retroperitoneal collections of fluid thought to be indicative of trauma. In the remaining 25 patients, screening ultrasonography showed no abnormalities, and injuries were detected by repeated ultrasonography, subsequent computed tomography, or diagnostic peritoneal lavage performed for suspected occult injury on the basis of clinical parameters. In addition, 47 of 126 injured patients with sonographically detected free fluid had parenchymal findings that helped localize injury. Sixteen of those patients were taken to the operating room on the basis of clinical and sonographic findings without undergoing computed tomography. CONCLUSIONS: The inability to show injuries with no hemoperitoneum or with delayed hemoperitoneum has been shown to be a limitation of ultrasonography in patients with blunt trauma. In our series, 26% of all patients with documented injuries had no free fluid visible on screening ultrasonography Attention to findings other than free fluid allowed detection in 43% of injured patients without sonographic evidence of hemoperitoneum.     

Evaluating blunt abdominal trauma:role for ultrasonography.

Patients in unstable condition with suspected blunt abdominal trauma require rapid evaluation to assess the need for laparotomy. Ultrasonography is fast and uses portable equipment, and it can be used in the resuscitation area to detect free intraperitoneal fluid as an indication of intraabdominal injury in the patient in unstable condition. To determine the utility of emergency abdominal sonography for evaluating patients with blunt abdominal trauma, a prospective study was designed to compare ultrasonography to diagnostic peritoneal lavage. Emergency sonography was performed prior to diagnostic peritoneal lavage on 54 acutely injured patients in the resuscitation area. Our results reveal that ultrasonography has a sensitivity of 87%, a specificity of 100%, and an overall accuracy of 96% for detecting free intraperitoneal fluid. We conclude that ultrasonography is a reliable method for the emergent evaluation of blunt abdominal trauma and can be used in place of diagnostic peritoneal lavage as the initial indicator of significant intraperitoneal injury requiring surgical intervention.     

Hollow organ perforation in blunt abdominal trauma: the role of diagnostic peritoneal lavage

Background

With recent advances in radiologic diagnostic procedures, the use of diagnostic peritoneal lavage (DPL) has markedly declined. In this study, we reviewed data to reevaluate the role of DPL in the diagnosis of hollow organ perforation in patients with blunt abdominal trauma.

Methods

Adult patients who had sustained blunt abdominal trauma and who were hemodynamically stable after initial resuscitation underwent an abdominal computed tomographic (CT) scan. Diagnostic peritoneal lavage was performed for patients who were indicated to receive nonoperative management and where hollow organ perforation could not be ruled out.

Results

During a 60-month period, 64 patients who had received abdominal CT scanning underwent DPL. Nineteen patients were diagnosed as having a positive DPL based on cell count ratio of 1 or higher. There were 4 patients who sustained small bowel perforation. The sensitivity and specificity of the cell count ratio for a hollow organ perforation in this study were 100% and 75%, respectively. No missed hollow organ perforations were detected.

Conclusion

For patients with blunt abdominal trauma and hemoperitoneum who plan to receive nonoperative management, DPL is still a useful tool to exclude hollow organ perforation that is undetected by CT.     

Diagnosis of bowel and mesenteric injuries in blunt abdominal trauma: a prospective study

PURPOSE: Currently, nonoperative management is the procedure of choice for solid organ injury in patients with a blunt abdominal trauma. Missed blunt bowel and mesenteric injuries (BBMIs) are possible because diagnosis is difficult. The aim of our study was to test a new algorithm for BBMI diagnosis using abdominal ultrasonography (AUS), computed tomography (CT), and diagnostic peritoneal lavage (DPL). METHODS: We reviewed cases of blunt abdominal injuries over a 10-year period, then we designed an algorithm that was prospectively tested in hemodynamically stable patients over a 2-year period. An abnormal AUS led to helical CT. When the CT showed more than 2 findings suggestive of BBMI, laparotomy was performed. In case of 1 or 2 abnormal CT findings, we performed a DPL and calculated the ratio of white blood cells (WBCs) to red blood cells (RBCs) (WBC/RBC ratio) in the lavage fluid and divided this by the WBC/RBC ratio in peripheral blood. A ratio of 1 or higher was considered positive for BBMI, and a laparotomy was immediately performed. Patients with a ratio of less than 1 were managed nonoperatively. RESULTS: In the retrospective study, 26 (1%) of 2126 patients admitted to our trauma center for blunt trauma had a BBMI, including 15 (58%) diagnosed after a median delay of 24 hours. In the prospective study, 531 patients were admitted for blunt trauma with multiple injuries, including 131 with abdominal trauma. Computed tomography was performed in 40 patients. There were 2 criteria or more of BBMI in 1 patient, 0 criteria in 27 patients (with an uneventful follow-up), and 1 or 2 criteria in 12 patients who had DPL with a median ratio of 0.82 (ranges, 0.03-9). Five patients had a ratio of 1 or higher. They underwent immediate laparotomy. In all 5 cases, BBMI was found. The 7 patients who had a ratio of less than 1 were observed in ICU and treated for extra-abdominal injuries. No BBMI injury was missed in these patients. The accuracy of the algorithm was 100% (95% confidence interval, 0.99-1.00). CONCLUSION: The proposed algorithm (based on AUS, CT, and DPL) had a high accuracy to diagnose BBMI while requiring the performance of DPL in only a few (2%) patients.     

Prospective evaluation of non-radiologist performed emergency abdominal ultrasound for haemoperitoneum

Objectives: To evaluate non-radiologist performed emergency ultrasound for the detection of haemoperitoneum after abdominal trauma in a British accident and emergency department.

Methods: Focused assessment with sonography for trauma (FAST) was performed during the primary survey on adult patients triaged to the resuscitation room with suspected abdominal injury over a 12 month period. All investigations were performed by one of three non-radiologists trained in FAST. The ultrasound findings were compared against the investigation of choice of the attending surgeon/accident and emergency physician. The patients were followed up for clinically significant events until hospital discharge or death.

Results: One hundred patients who had sustained blunt abdominal trauma, were evaluated by FAST. Nine true positive scans were detected and confirmed by computed tomography, diagnostic peritoneal lavage, or laparotomy. There was one false positive in this group, giving a sensitivity of 100%, specificity 99%, and positive predictive value of 90%. Ten patients with penetrating injuries were evaluated with a sensitivity and specificity for FAST of 33% and 86% respectively.

Conclusions: Emergency torso ultrasound for the detection of haemoperitoneum can be successfully performed by trained non-radiologists within a British accident and emergency system. It is an accurate and rapid investigation for blunt trauma, but the results should be interpreted with caution in penetrating injury.

     

Peritoneal lavage for the diagnosis of abdominal visceral injury

Peritoneal lavage has become standard for the diagnosis of abdominal visceral injury following trauma. Peritoneal lavage is indicated after blunt trauma when a patient presents with abdominal symptoms or signs and the integrity of the abdominal viscera is in doubt. Immediate laparotomy may be indicated following penetrating abdominal wounds when symptoms, signs, or hypotension are present. However, peritoneal lavage may be indicated if the patient is asymptomatic. Lavage is also indicated after penetrating extra-abdominal wounds when the path of the wounding agent suggests that the peritoneal cavity might have been entered. Peritoneal lavage is 98% accurate in determining the presence or absence of abdominal visceral injury following blunt trauma (100,000 red blood cells [RBCs]/mm3 or 500 white blood cells [WBCs]/mm3). The diagnostic accuracy of peritoneal lavage in penetrating abdominal injuries is more controversial than in blunt trauma, but recent retrospective data suggest that peritoneal lavage has the potential of giving 98% accurate results following penetrating abdominal injury when the threshold for a positive result of lavage is lowered to 50,000 RBCs/mm3 or 500 WBCs/mm3.     

Operative versus nonoperative management of blunt abdominal trauma: Role of ultrasound-measured intraperitoneal fluid levels.

This study's objective was to analyze whether the quantity of free intraperitoneal fluid on ultrasonography, alone or in combination with unstable vital signs, is sensitive in determining the need for laparotomy in patients presenting with blunt trauma. Adult patients who presented with blunt abdominal trauma to 2 level I trauma centers were enrolled. Combined intraperitoneal fluid levels (anechoic stripe) of 5 intraperitoneal areas were measured and defined as small (< 1.0 cm), moderate (> 1.0 cm, < 3.0 cm), or large (> 3.0 cm). Unstable vital signs were defined as pulse > 100 bpm or systolic blood pressure < 90 mmHg. Exploratory laparotomy or computed tomography scan confirmed hemoperitoneum. Of 270 patients entered into the study, ultrasound detected free intraperitoneal fluid in 33 patients. Of the 18 patients with a large fluid accumulation, 16 underwent exploratory laparotomy (89% sensitivity), and all 8 patients with unstable vital signs underwent exploratory laparotomy (100% sensitivity). Of the 10 patients with a moderate fluid accumulation, 6 underwent exploratory laparotomy (60% sensitivity), and 4 of the 6 patients with unstable vital signs underwent exploratory laparotomy (67% sensitivity). A large intraperitoneal fluid accumulation on ultrasonography in combination with unstable vital signs, is sensitive for determining the need for exploratory laparotomy in patients presenting with blunt trauma.     

Sonography as the primary screening method in evaluating blunt abdominal trauma

PURPOSE: The radiological evaluation of patients with blunt abdominal trauma can be done with either ultrasound (US) or computed tomography (CT) with strategies varying considerably among institutions. We evaluated the efficacy of our current strategy in which US is used at our hospital as the primary screening tool for patients with blunt abdominal trauma. METHODS: We retrospectively analysed all patients admitted to our hospital with possible blunt abdominal trauma who underwent abdominal US, abdominal CT and/or a laparotomy during the initial trauma assessment from 1998 until 2002 (n = 1149). RESULTS: Nine-hundred sixty-one of the 1149 patients had a negative US, of which 922 were true negative, resulting in a negative predictive value of 96%. A CT of the abdomen was performed in 7%. In 1.7% there was delayed diagnosis with no significant additional morbidity. Fourteen of the 103 laparotomies (14%) were non-therapeutic; in 5 of these cases the patients underwent non-therapeutic laparotomy despite the performance of a CT. Seven were emergency operations. CONCLUSIONS: In our practice, the use of US for the evaluation of acute blunt abdominal trauma is adequate, with a high negative predictive value, a small number of delayed diagnoses, and an acceptable rate of non-therapeutic laparotomies.     

Diagnostic peritoneal lavage and ultrasonography for blunt abdominal trauma: attitudes and training of current general surgical trainees.

OBJECTIVE: It has been suggested that diagnostic peritoneal lavage is now obsolete in UK hospitals with access to either skilled ultrasonography or emergency physician or surgeon-performed focused abdominal sonography in trauma. Diagnostic peritoneal lavage continues to be advocated and taught on Advanced Trauma Life Support courses. The aim of this study was to evaluate the experiences and attitudes of general-surgery trainees in one UK training region towards diagnostic peritoneal lavage and focused abdominal sonography in trauma in managing blunt abdominal trauma. METHODS: An anonymous postal piloted questionnaire was sent to all 66 general surgery specialist trainees in one UK training region between January and March 2005. RESULTS: Out of 40 replies to the questionnaire (response rate 61%), 53% and 38% of surgical trainees had either never performed or never observed a diagnostic peritoneal lavage during their training. Thirteen trainees (33%) felt diagnostic peritoneal lavage to be obsolete and would never contemplate using it; 15 trainees (37%) might consider using diagnostic peritoneal lavage if computed tomography or ultrasonography were unavailable. Ten trainees (25%) felt that diagnostic peritoneal lavage had been superseded by computed tomography. Only 12 trainees (30%) had worked in a UK hospital with access to facilities for focused abdominal sonography in trauma and only seven trainees (18%) had received any training or experience in focused abdominal sonography in trauma. CONCLUSIONS: Surgical trainees in one UK training region lack skills in both diagnostic peritoneal lavage and focused abdominal sonography in trauma for managing blunt abdominal trauma and are therefore reliant upon the availability of prompt, skilled radiological assistance or emergency physician-provided focused abdominal sonography in trauma.     

Comparison of the Accuracy and Reproducibility of Focused Abdominal Sonography for Trauma Performed by Emergency Medicine and Radiology Residents

We compared the diagnostic accuracy of emergency medicine residents (EMRs) and radiology residents (RRs) in performing focused abdominal sonography for trauma (FAST). The cohort in this prospective study comprised 200 unstable patients (163 males and 37 females; mean ± standard deviation of age, 34.3 ± 16.4 y) who presented with trauma. These patients were evaluated using FAST, first by EMRs and subsequently by RRs. Patients with positive FAST results underwent further diagnostic procedures such as computed tomography, diagnostic peritoneal lavage and laparotomy. Those with negative FAST results underwent clinical follow-up for 72 h until their condition deteriorated or they were discharged. Sensitivity, specificity, positive and negative predictive values and accuracy in evaluating free intraperitoneal fluid were 80%, 95%, 57%, 98% and 94% when FAST was performed by EMRs and 86%, 95%, 59%, 98% and 94% when FAST was performed by RRs. The level of agreement between EMRs and RRs was moderate (κ = 0.525). FAST is a useful screening tool for initial assessment of free abdominal fluid in patients with trauma. Our results indicate that EMRs can perform sonography on trauma patients as successfully as RRs.     

Is Closed Diagnostic Peritoneal Lavage Contraindicated in Patients with Previous Abdominal Surgery?

Objective: To compare the accuracies and complication rates of diagnostic peritoneal lavage (DPL) in trauma patients with and without previous abdominal surgery. Methods: A retrospective review of DPL accuracy and complication rate was performed using all ED trauma patients who underwent DPL during 1993 as identified by the trauma registry. Care was provided at a Level-1 trauma center, a 1,100-bed, central-city teaching hospital with an annual ED census of 84,000. Records were reviewed for a history of previous surgery, DPL results, complications, mechanism of injury, and location of abdominal scars. DPL was performed using the Seldinger technique with a standard Arrow Diagnostic Peritoneal Lavage Kit using an 8-Fr catheter. Rates for patient groups with and without previous abdominal surgery were compared using Fisher's exact test. A “misclassified” DPL was defined as either a positive DPL with negative laparotomy or a negative DPL with subsequent need for laparotomy. “Complications” were defined as iatrogenic injury during the procedure or inability to obtain return of fluid during the lavage. Results: A total of 372 DPLs were performed; 42 in patients with previous surgery and 330 in patients without prior surgery. The groups were similar with respect to proportion with blunt trauma (95% vs 97%), positive DPL (19% vs 19%), misclassified rate (2.4% vs 1.8%), and complication rate (2.4% vs 0.9%); no significant difference was found between groups. The previous abdominal surgeries were appendectomy (n = 20), tubal ligation (n = 5), abdominal hysterectomy (n = 4), cholecystectomy (nonlaparoscopic) (n = 4), pyloric stenosis (n = 1), uterine prolapse (n = 1), undescended testis (n = 1), partial gastrectomy (n = 1), and unknown (n = 5). The analysis had a 90% power of detecting a 10% difference between the 2 groups. Conclusion: The complication rate and accuracy of closed DPL in patients with previous abdominal surgery were similar to those for DPL performed in patients without previous abdominal surgery.     

Nonoperative management of blunt abdominal trauma in pediatrics

The management of blunt abdominal trauma in children has undergone significant modification in the past decade because of advances in diagnostic imaging and an improved understanding of the natural history of injury to the spleen and liver. Mandatory laparotomy for proven or suspected hemoperitoneum has been replaced by intensive observation of most patients who are stable or who can be stabilized in the Emergency Department. The result has been a significant reduction in morbidity owing to anesthetic complications, postsplenectomy sepsis, and peritoneal adhesions. To take full advantage of these advances, emergency physicians and other primary care providers should be aware of the often subtle manifestations of abdominal trauma, the available diagnostic modalities and their limitations, and the requirements for volume resuscitation in pediatric patients.     

Value of computed tomography in the evaluation of retroperitoneal organ injury in blunt abdominal trauma

Computed tomography (CT) is widely used in the evaluation of blunt abdominal trauma. One of its purported advantages is in the evaluation of the retroperitoneum. This study was undertaken to determine the utility of CT in diagnosing retroperitoneal organ injury. A retrospective chart review of 466 stable patients with blunt abdominal trauma who received abdominal CT was conducted. Twelve percent of the patients had CT scans showing retroperitoneal organ injury. There were 58 total injuries, with the kidney being the most frequently injured organ. Twenty-four patients required laparotomy, confirming the CT diagnosis in 8 patients (7 renal and 1 pancreatic). Two duodenal injuries were found at laparotomy that had not been seen on CT scan. Fourteen percent of the patients with positive CT scans had a positive laparotomy, and of those, 38% were therapeutic. Five percent of the patients with positive scans had therapeutic laparotomies. These data infer that the utility of CT to define retroperitoneal organ injury is lower than previously suspected.     

腹腔镜治疗腹部闭合性外伤临床分析

目的探讨腹腔镜在治疗腹部闭合性外伤中的临床价值。方法回顾性分析25例腹部外伤腹腔镜探查应用的临床资料结果24例在腹腔镜下明确诊断（96．00％）,其中19例腹腔镜下完成手术,5例转开腹完成手术。全组均痊愈出院,无死亡病例。结论在腹部外伤病人中选择适合的病人进行腹腔镜治疗,具有安全可靠、创伤小、恢复快的特点,有助于降低治疗风险．避免部分不必要的开腹手术。     

The fast is positive,now what? Derivation of a clinical decision rule to determine the need for therapeutic laparotomy in adults with blunt torso trauma and a positive trauma ultrasound

INTRODUCTION: The object of this study was to derive a clinical decision rule for therapeutic laparotomy among adult blunt trauma patients with a positive abdominal ultrasound for trauma (FAST) examination. METHODS: We retrospectively reviewed the trauma registry and medical records of all critical trauma patients who underwent a FAST examination in the emergency department (ED) in a university Level I trauma center over a 3-year period. Blunt trauma patients aged >16 years who had a positive FAST examination (defined as the presence of intraperitoneal fluid) were eligible. We selected seven clinical and ultrasound variables available during ED resuscitation for analysis: age, presence of an episode of hypotension (systolic blood pressure <90 torr in the ED), presence of abdominal tenderness, chest injury, pelvic fracture, femur fracture, and FAST fluid location (right upper quadrant [RUQ] only; RUQ plus other location; other location only). The primary outcome variable was whether a laparotomy was performed and whether this laparotomy was needed to provide the definitive surgical intervention ("therapeutic laparotomy"). We analyzed the variables using binary recursive partitioning analysis to create a decision rule. RESULTS: There were 2336 FAST examinations performed during the study period, resulting in 230 (9.8%) positive examinations in patients meeting inclusion criteria. There were 135 patients who had therapeutic laparotomies and 95 who did not need laparotomy. The groups were similar in baseline characteristics. In the recursive partitioning analysis, the first node in the decision tree was the presence of fluid in the RUQ. Of the 144 patients with RUQ fluid, 105 (73%, 95% confidence interval [CI] 64%-80%) required therapeutic laparotomy. Of the 86 patients without RUQ fluid, 30 (35%, 95% CI 25%-46%) nevertheless required therapeutic laparotomies, and the variables blood pressure, femur fracture, abdominal tenderness, and age further divided these patient into high- and low-risk groups. Of the 12 patients without RUQ fluid who had normal blood pressures, no femur fractures, no abdominal tenderness, and were aged 60 years and younger, none (95% CI 0%-22%) required therapeutic laparotomy. In conclusion, given a positive FAST examination, the presence of fluid in the RUQ is an important predictor of the need for therapeutic laparotomy. CONCLUSION: In the absence of fluid in the RUQ, there are other clinical variables that may allow for the development of a clinical decision rule regarding the need for therapeutic laparotomy.     

Sensitivity in detecting free intraperitoneal fluid with the pelvic views of the FAST exam

The multiple-view focused assessment with sonography for trauma (FAST) exam is an integral tool in the assessment of blunt abdominal trauma. A prospective observational study was performed to compute the average minimum volume of detectable intraperitoneal fluid with the pelvic views of the FAST exam. All adult patients from October 1999 to May 2001, who presented to the ED with blunt abdominal trauma and underwent a clinically indicated diagnostic peritoneal lavage (DPL), were candidates for admission to the pelvic ultrasound study. In the supine position, patients were administered lavage fluid in 100 cc increments until the examiner detected the fluid on ultrasound. An independent reviewer also examined the hard-copy ultrasound images for fluid detection. Patients were excluded if they had (1) a positive DPL for hemoperitoneum (defined as 10 cc of gross blood or >100,000 red blood cells/mL), (2) a positive initial ultrasound for free fluid, or (3) lacked sufficient hard-copy ultrasound images. The mean minimal volume of fluid needed for pelvic ultrasound detection by the examiner and reviewer was 157 and 129 cc (n = 7), respectively. The median quantity of fluid for ultrasound detection by both the examiner and reviewer was 100 cc. The pelvic views of the FAST exam identified a significantly smaller quantity of intraperitoneal fluid than previous studies of the right upper quadrant single-view exam.     

Abdominal stab wounds: a five-year patient review.

Over a period of 5 years, 101 patients were treated for abdominal stab wounds at our emergency department. Exploratory laparotomy was performed in 41 of these cases. The indication for laparotomy was set by clinical investigation in 20 cases, instrumental exploration in six patients, ultrasound in six, paracentesis in seven and computerized tomography scanning in two cases. A review of the results of the treatment of these abdominal stab wounds is compared with the literature. Routine laparotomy for this type of penetrating trauma to the abdomen proves to be no longer warranted. Clinical and especially diagnostic studies should be able to select patients in whom laparotomy should be performed. When these studies are unable to exclude severe injury, laparotomy remains more prudent than expectant observation.     

Serial abdominal ultrasound in the setting of trauma

Ultrasound is gaining wide acceptance in Emergency Medicine as an inexpensive and accurate examination modality. One of the leading uses of this technology is in the initial assessment of the trauma patient, where the ultrasound examination is often used to determine the need for immediate laparotomy or further diagnostic study. We present a series of four patients, all of whom sustained blunt or penetrating abdominal trauma. In each case, the initial screening abdominal ultrasound was negative for free intraperitoneal (i.p.) fluid but, when repeated by the same practitioner, became positive. These cases demonstrate the need for serial ultrasounds in evaluating the patient with abdominal trauma. Future studies of trauma ultrasound should investigate the utility of serial sonographic examinations.     

Screening sonography in pregnant patients with blunt abdominal trauma.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of screening sonography for the detection of clinically significant abdominal injury in pregnant patients with blunt trauma. METHODS: We retrospectively reviewed the records of 5173 patients with blunt abdominal trauma who underwent screening sonography. Pregnant patients were identified, and the prospective sonographic interpretations were compared with surgical findings, computed tomography (CT), subsequent sonography, cystography, and the clinical course. RESULTS: Of 1567 female patients with trauma, 947 were of reproductive age and, 102 (11%) of these 947 were pregnant. One patient was excluded because a truth standard was not available. Five (5%) of these 101 patients were found to have injuries at surgery. These injuries involved the placenta (2 injuries), spleen (2 injuries), liver (1 injury), and kidney (1 injury); all required surgery. Initial sonographic findings were positive in 4 of 5 patients with injuries. The missed injury was a placental injury detected 15 hours after screening sonography because of fetal bradycardia. After screening sonography, 6 patients underwent additional abdominal imaging: CT (3 patients), cystography (1 patient), and additional sonography (2 patients). Of 101 patients, 95 (94%) required no additional tests, and 97 (96%) required no test involving ionizing radiation. No pregnant patient underwent diagnostic peritoneal lavage. Sensitivity was 80% (95% confidence interval, 28%-100%), and specificity was 100% (96 of 96; 95% confidence interval, 96%-100%) for detecting major abdominal injury. CONCLUSIONS: Sonography is an effective screening examination that can obviate more hazardous tests such as CT, cystography, and peritoneal lavage in most pregnant patients with trauma requiring objective evaluation of the abdomen.     

Objective determination of the optimal red blood cell count in diagnostic peritoneal lavage done for abdominal stab wounds.

The purpose of this study was to determine objectively the optimal value or positivity criterion for red blood cell counts in diagnostic peritoneal lavage in stab wounds to the anterior abdomen. Our study group consisted of 91 consecutive adults with abdominal stab wounds who underwent peritoneal lavage. We excluded those patients who met criteria for immediate laparotomy and those with negative stab wound exploration. We divided the patients into two groups based on outcome. Group 1 consisted of those who had undergone laparotomy and had findings that required surgical intervention. Group 2 patients had either undergone laparotomy but had no injury requiring surgical intervention or had no surgery and a benign hospital course and follow-up. Receiver operator characteristic analysis was done on the diagnostic peritoneal lavage RBC counts for both groups. The overlap between the groups was minimal, with 75% of patients in Group 1 having > 120,000 RBC/mm3 and 75% of patients in Group 2 having < 486 RBC/mm3 in the lavage effluent. Using the observed probability of 23.1% of patients with abdominal stab wounds requiring surgery, a RBC count of 50,000/mm3 discriminated best those patients who required surgery from those who did not.