Significant hemoperitoneum in blunt trauma victims with normal vital signs and clinical examination

Deep learning for emergency ascites diagnosis using ultrasonography images

PURPOSE

The detection of abdominal free fluid or hemoperitoneum can provide critical information for clinical diagnosis and treatment, particularly in emergencies. This study investigates the use of deep learning (DL) for identifying peritoneal free fluid in ultrasonography (US) images of the abdominal cavity, which can help inexperienced physicians or non-professional people in diagnosis. It focuses specifically on first-response scenarios involving focused assessment with sonography for trauma (FAST) technique.

METHODS

A total of 2985 US images were collected from ascites patients treated from 1 January 2016 to 31 December 2017 at the Shenzhen Second People's Hospital. The data were categorized as Ascites-1, Ascites-2, or Ascites-3, based on the surrounding anatomy. A uniform standard for regions of interest (ROIs) and the lack of obstruction from acoustic shadow was used to classify positive samples. These images were then divided into training (90%) and test (10%) datasets to evaluate the performance of a U-net model, utilizing an encoder-decoder architecture and contracting and expansive paths, developed as part of the study.

RESULTS

Test results produced sensitivity and specificity values of 94.38% and 68.13%, respectively, in the diagnosis of Ascites-1 US images, with an average Dice coefficient of 0.65 (standard deviation [SD] = 0.21). Similarly, the sensitivity and specificity for Ascites-2 were 97.12% and 86.33%, respectively, with an average Dice coefficient of 0.79 (SD = 0.14). The accuracy and area under the curve (AUC) were 81.25% and 0.76 for Ascites-1 and 91.73% and 0.91 for Ascites-2.

CONCLUSION

The results produced by the U-net demonstrate the viability of DL for automated ascites diagnosis. This suggests the proposed technique could be highly valuable for improving FAST-based preliminary diagnoses, particularly in emergency scenarios.

Flat Inferior Vena Cava: Indicator of Poor Prognosis in Trauma and Acute Care Surgery Patients

Flat inferior vena cava (IVC) on ultrasound examination has been shown to correlate with hypovolemic status. We hypothesize that a flat IVC on limited echocardiogram (LTTE) performed in the emergency room (ER) correlates with poor prognosis in acutely ill surgical patients. We conducted a retrospective review of all patients undergoing LTTE in the ER from September 2010 until June 2011. IVC diameter was estimated by subxiphoid window. Flat IVC was defined as diameter less than 2 cm. Fat IVC was defined as diameter greater than 2 cm. Need for intensive care unit admission, blood transfusion requirement, mortality, and need for emergent operation between patients with flat versus Fat IVC were compared. One hundred one hypotensive patients had LTTE performed in the ER. Average age was 38 years. Admission diagnosis was blunt trauma (n = 80), penetrating trauma (n = 13), acute care surgery pathology (n = 7), and burn (n = 1). Seventy-four patients had flat IVC on initial LTTE. Compared with those with fat IVC, flat patients were found have higher rates of intensive care unit admission (51.3 vs 14.8%; P = 0.001), blood transfusion requirement (12.2 vs 3.7%), and mortality (13.5 vs 3.7%). This population also underwent emergent surgery on hospital Day 1 more often (16.2 vs 0%; P = 0.033). Initial flat IVC on LTTE is an indicator of hypovolemia and a predictor of poor outcome.

A short report on the acquisition of point-of-care ultrasound skills and knowledge by the ambulance personnel in Hong Kong

Background:

Point-of-care ultrasound plays an important role in patient management in the prehospital setting. Prehospital ultrasound training for the paramedics has been developed in the West for many years. However, the present training curriculum for the local ambulance personnel does not include point-of-care ultrasound. This study is the first of its kind in Hong Kong on the feasibility of teaching ambulance personnel how to perform focused assessment with sonography in trauma by a 1-day course.

Objective:

It aimed to assess whether the ultrasound-naïve ambulance personnel could acquire the skills and knowledge of point-of-care ultrasound following a tailor-made training programme.

Methods:

This was a prospective observational study. The training programme was a 1-day course consisted of didactic lectures and hands-on practice. Each participant was assessed by a written test and a skills test. Descriptive statistics were used to describe the ambulance personnel and their results of the written and skills test. Significance testing was by Mann–Whitney U test and Spearman correlation test where appropriate.

Results:

Seventeen members of Ambulance Service Institute (Hong Kong Branch) participated in the programme. All of them currently are the ambulance personnel and they joined the programme via the captioned institute. Enrollment was voluntary. The median score in the written test was 20 out of 25. The median time to complete the four views of the focused assessment with sonography in trauma scan was 3.4 min. There was no significant relationship between test performance and educational background and work experience of the ambulance personnel.

Conclusion:

Training the local ambulance personnel point-of-care ultrasound is feasible. Their acquisition of skills and knowledge of point-of-care ultrasound after a 1-day course was satisfactory.

Senior general surgery residents can be trained to perform focused assessment with sonography for trauma patients accurately

PURPOSES

Researchers studying trauma have found that physicians are able to perform a focused assessment with sonography for trauma (FAST) with minimal training and achieve ideal accuracy. However, there are currently no consensus or standard guidelines regarding the performance of this assessment. The aim of our study was to clarify the value of FAST performed by well-qualified senior general surgery residents in cases of suspected blunt abdominal trauma, which presents an important diagnostic problem in emergency departments.

METHODS

This was a retrospective study in the emergency department (ED) of our hospital performed from January 2011 to September 2013. Patients were included if they (1) had undergone a FAST examination performed by qualified residents and (2) had received subsequent formal radiographic or surgical evaluations. The results were compared against subsequent surgical findings or formal Department of Radiology reference standards.

RESULTS

Among the 438 patients enrolled, false-negative results were obtained in 8 and false-positive results in 5. Only one patient was missed and required laparotomy to repair a small intestine perforation. The sensitivity and specificity were 87 and 99%, respectively; the accuracy was 97%.

CONCLUSIONS

Senior general surgery residents can be trained to perform accurate FAST examinations on trauma patients.

I-FABP and L-FABP are early markers for abdominal injury with limited prognostic value for secondary organ failures in the post-traumatic course

BACKGROUND

Trauma patients sustaining abdominal trauma exhibit high risk of organ failure and/or sepsis aggravating morbidity and mortality during the post-traumatic course. The present study re-evaluates L- and I-FABPs (small fatty acid binding proteins) as early biomarkers for abdominal injury (AI) in a large cohort of patients and analyzes their potential as indicators of specific organ failure and their association with sepsis and/or mortality in the post-traumatic course.

METHODS

This prospective study included 134 multiply traumatized patients (ISS≥16). Fifty-nine had AI (abbreviated AI Scale, AISAbd≥3) and 75 had no AI (noAI). Twenty healthy volunteers served as controls. Plasma I- and L-FABP levels were measured at the admittance to the emergency room (d0) and up to 10 days daily (d1-d10) using ELISA. Sepsis, organ failure, multiple organ failure (MOF) and mortality were assessed.

RESULTS

Median L- and I-FABP in the AI-group [258 (IQR=71-500) ng/mL and 328 (IQR=148-640) pg/mL, respectively] were higher compared to noAI-group [30 (IQR=18-50) ng/mL and 60 (IQR=40-202) pg/mL, p>0.05] on d0. Sensitivity and specificity to detect AI were 80% and 75% for L-FABP, 78% and 62% for I-FABP. Both FABPs decline with the post-traumatic course to control levels. On d0 and d1, FABPs correlate with the Sepsis-related Organ Failure Assessment (SOFA) score of the following day (d0: ρ:0.33, ρ:0.46, d1: ρ:0.48, ρ:0.35). No other correlations were found. Eight percent of all patients developed sepsis, 18% pneumonia, 4% urinary tract infection, 3% acute kidney failure and one MOF. FABPs correlated neither with Simplifed Acute Physiology Score (SAPS)-II nor to sepsis. All patients with acute kidney failure demonstrated enhanced L-FAPB levels before the increase of serum creatinine levels.

CONCLUSIONS

Our results confirm the potential of L- and I-FABP to indicate abdominal injuries initially after trauma. Except L-FABP as indicator of acute kidney failure both FABPs have to be further evaluated as predictors for other organ failures, sepsis and/or mortality.

Ultrasound in pre-hospital trauma care

Pre-hospital medicine is developing rapidly. Increasingly, specialist pre-hospital medical practitioners are working in this environment and paramedics are advancing their skill base. Tools traditionally associated with hospital care are now used pre-hospital to improve diagnosis and intervention. In this paper, we assess the developing role of ultrasound in improving trauma care in the pre-hospital arena. Focused ultrasound is used to facilitate early diagnosis of pneumothorax and intraperitoneal/pericardial haemorrhage in trauma victims. Ultrasound may have a role in assessing the circulating blood volume, fracture diagnosis and triage in mass casualty scenarios. Information obtained using ultrasound may change diagnoses and consequently alter therapy, as well as patient disposition by highlighting injuries not identified on physical examination. Receiving hospitals can be alerted to injuries requiring intervention upon arrival. Ultrasound is also used to reduce complications and improve performance in numerous procedures such as obtaining vascular and intra-osseous access, paracentesis and tracheal tube placement. There is emerging evidence that ultrasound may be used safely pre-hospital without increasing on-scene times and with results comparable to use in hospital.

Ultrasound as a tool for fluid status assessment in the trauma and critically ill patient

Resuscitation to euvolemia in trauma as well as in the critically ill patient, continues to be a challenge. Focused cardiac ultrasound has been shown to be a reliable tool to evaluate fluid status and to guide therapy. The present manuscript reviews the evidence supporting the use of this tool and describes the clinical applications for image-based resuscitation using echocardiogram.

[Value of clinical key symptoms in the primary treatment of severely injured patients]

BACKGROUND

The initial diagnostic procedure of severely injured patients in the emergency room (ER) during the primary survey is first and foremost a clinical examination. The clinical S3 guidelines provide recommendations for the treatment of patients with severe and multiple injuries.

OBJECTIVES

The study was performed to investigate the reliability of clinical key symptoms or red flags registered in the ER that lead to further diagnostic or therapeutic procedures.

MATERIAL AND METHODS

An evaluation of key symptoms as a synopsis of the current literature considering aspects of probability calculation and medical experience was carried out.

RESULTS

Key symptoms registered during the clinical examination are not sufficiently safe to be solely relied upon for further diagnostic and therapeutic decisions. This confirms the sense of purpose of the strict approach according to the advanced trauma life support (ATLS) algorithm. Red flags can serve as a warning to focus on relevant injuries early on. A rational imaging diagnostic procedure must follow.

Emergency Ultrasound Predicting the Need for Therapeutic Laparotomy among Blunt Abdominal Trauma Patients in a Sub-Saharan African Hospital

Background. The trauma burden globally accounts for high levels of mortality and morbidity. Blunt abdominal trauma (BAT) contributes significantly to this burden. Patient's evaluation for BAT remains a diagnostic challenge for emergency physicians. SSORTT gives a score that can predict the need for laparotomy. The objective of this study was to assess the accuracy of SSORTT score in predicting the need for a therapeutic laparotomy after BAT. Method. A prospective observational study. Eligible patients were evaluated for shock and the presence of haemoperitoneum using a portable ultrasound machine. Further evaluation of patients following the standard of care (SOC) protocol was done. The accuracy of SSORTT score in predicting therapeutic laparotomy was compared to SOC. Results. In total, 195 patients were evaluated; M : F ratio was 6 : 1. The commonest injuries were to the head 80 (42%) and the abdomen 54 (28%). A SSORTT score of >2 appropriately identified patients that needed a therapeutic laparotomy (with sensitivity 90%, specificity 90%, PPV 53%, and NPV 98%). The overall mortality rate was 17%. Conclusion. Patients with a SSORTT score of 2 and above had a high likelihood of requiring a therapeutic laparotomy. SSORTT scoring should be adopted for routine practice in low technology settings.

Blunt abdominal trauma patients are at very low risk for intra-abdominal injury after emergency department observation

Introduction

Patients are commonly admitted to the hospital for observation following blunt abdominal trauma (BAT), despite initially negative emergency department (ED) evaluations. With the current use of screening technology, such as computed tomography (CT) of the abdomen and pelvis, ultrasound, and laboratory evaluations, it is unclear which patients require observation. The objective of this study was to determine the prevalence of intra-abdominal injury (IAI) and death in hemodynamically normal and stable BAT patients with initially negative ED evaluations admitted to an ED observation unit and to define a low-risk subgroup of patients and assess whether they may be discharged without abdominal/pelvic CT or observation.

Methods

This was a retrospective cohort study performed at an urban level 1 trauma center and included all BAT patients admitted to an ED observation unit as part of a BAT key clinical pathway. All were observed for at least 8 hours as part of the key clinical pathway, and only minors and pregnant women were excluded. Outcomes included the presence of IAI or death during a 40-month follow-up period. Prior to data collection, low-risk criteria were defined as no intoxication, no hypotension or tachycardia, no abdominal pain or tenderness, no hematuria, and no distracting injury. To be considered low risk, patients needed to meet all low-risk criteria.

Results

Of the 1,169 patients included over the 2-year study period, 29% received a CT of the abdomen and pelvis, 6% were admitted to the hospital from the observation unit for further management, 0.4% (95% confidence interval [CI], 0.1%–1%) were diagnosed with IAI, and 0% (95% CI, 0%–0.3%) died. Patients had a median combined ED and observation length of stay of 9.5 hours. Of the 237 (20%) patients who met low-risk criteria, 7% had a CT of the abdomen and pelvis and 0% (95% CI, 0%–1.5%) were diagnosed with IAI or died.

Conclusion

Most BAT patients who have initially negative ED evaluations are at low risk for IAI but still require some combination of observation and CT. A subgroup of BAT patients may be safely discharged without CT or observation after the initial evaluation.

Does prehospital ultrasound improve treatment of the trauma patient? A systematic review

Ultrasound (US) has been used for in-hospital evaluation of the trauma victim for many years. The outcome in severely injured patients remains heavily influenced by initial life support and early care, as time plays a major role. Development of handheld, battery-powered, low-weight US machines has created the possibility of bringing US to the prehospital setting, thus gaining a potential for early diagnosis and treatment. The objective of this study was to systematically search the literature for evidence that prehospital US of the abdomen or thorax increases survival of trauma patients. The data regarding the use of US in the prehospital setting is sparse, often of low quality and describing a broad variety of patients and clinical challenges. Therefore, from an evidence point of view it is not possible to answer the objectives in this review. In the prehospital setting, rapid assessment plays an important role, as initial life support and early surgical care influences the outcome of the severely injured patient. Time is especially crucial in blunt abdominal trauma and penetrating truncal injuries. Several studies in this review showed that prehospital US is feasible and that the procedure is highly reliable in detection of haemoperitoneum or haemopericardium compared with the low accuracy of physical examination and haemodynamic measurements. An early diagnosis will provide the prehospital physician with the knowledge to prioritize the relevant initial treatment and to choose the closest appropriate hospital and transportation form. There is currently no evidence in the literature that prehospital US of the abdomen or thorax improves treatment of trauma patients.

Tissue Doppler of early mitral filling correlates with simulated volume loss in healthy subjects

OBJECTIVES

The accurate noninvasive assessment of preload in emergency department (ED) patients remains elusive. Point-of-care ultrasound (US) imaging, particularly evaluation of the inferior vena cava (IVC), has been shown to be qualitatively helpful. Doppler and tissue Doppler are now routinely available on ED US equipment, but few studies have looked at the correlation of dynamic changes in these parameters in a controlled model of hypovolemia. Our objective was to examine the correlation of Doppler parameters to simulated volume loss in healthy subjects using a lower-body negative pressure (LBNP) model and to compare these measurements to commonly used IVC measurements of preload.

METHODS

Twelve paid volunteers with no known cardiovascular disease between the ages of 23 and 31 years old (mean ± SD = 25.5 ± 2.5 years old) were recruited. Hypovolemia was simulated using graduated LBNP levels with measurements taken at 0, -30, and -60 mm Hg and lower pressures as tolerated. Vital signs were monitored in all patients. US measurements recorded at each negative pressure level included IVC maximum (IVC(max)) and minimum (IVC(min)) dimensions; early (E) and late (A) transmitral filling velocities using pulsed-wave spectral Doppler; and early (E') and late (A') tissue Doppler velocities at the septal ((sep)) and lateral ((lat)) mitral annulus, using pulsed-wave tissue Doppler.

RESULTS

Lower-body negative pressure correlated significantly and positively within subjects for all US parameters except for the A filling wave. E'(lat) and E'(sep) showed the strongest correlation with R² values of 0.749 (95% confidence interval [CI] = 0.577 to 0.854) and 0.738 (95% CI = 0.579 to 0.875) respectively, followed by A'(sep) 0.674 (95% CI = 0.416 to 0.845), IVC(max) 0.638 (95% CI = 0.425 to 0.806), A'(lat) 0.547 (95% CI = 0.280 to 0.802), IVC(min) 0.512 (95% CI = 0.192 to 0.777), and E 0.478 (95% CI = 0.187 to 0.762). Ratios correlated only moderately with LBNP level, including E/ E'(lat) R² of 0.430 (95% CI = 0.131 to 0.706), E/ E'(sep) 0.416 (95% CI = 0.183 to 0.686), and IVC collapsibility index (IVC(CI)) 0.201 (95% CI = 0.003 to 0.681). Vital signs, including heart rate and blood pressure, did not vary significantly with LBNP levels.

CONCLUSIONS

In this pilot study of healthy subjects, tissue Doppler assessment of early diastolic filling correlated most strongly with simulated hypovolemia.

[Training in emergency sonography for trauma. Concept of a 1-day course program]

In the last decade prehospital focused abdominal sonography for trauma (P-FAST) could be established as a valid on-site diagnostic tool for both air and ground rescue medical services in Germany. An appropriate use of P-FAST demands a standardized training concept. Therefore a 1-day training program was developed by the working group "emergency ultrasound" in Frankfurt/Main and was introduced in 2003. The training consists of lectures on general and specific aspects of emergency ultrasound techniques with demonstrations of numerous pathological findings, intensive hands-on training with patients and volunteers, as well as simulated on-site training. After completing the P-FAST course the participants gained competency to perform prehospital emergency ultrasound with high accuracy. Strict application of the exact technique as well as appropriate integration of the adjunct into the algorithm of prehospital care are the most important prerequisites for successful use of P-FAST. From February 2003 to March 2008 540 participants were trained in P-FAST in the 1-day course.

Prehospital and Emergency Department Ultrasound in Blunt Abdominal Trauma

Blunt abdominal trauma is a challenging aspect of trauma management. Early detection has a major impact on patient outcome. In contrast to physical examination, computed tomography is known to be a sensitive and specific test for blunt abdominal injuries. However, it is time-consuming and thus contraindicated in hemodynamically unstable patients. Therefore, focused assessment with sonography for trauma (FAST) offers a fast and easily applicable screening method to identify patients for urgent laparotomy without any further diagnostics. FAST detects, with high sensitivity, intraperitoneal fluid that accumulates in dependent areas indicating blunt abdominal trauma. FAST has been established as a gold standard early screening method for blunt abdominal trauma when performing trauma management in the emergency department (ED) based on the Advanced Trauma Life Support(®) algorithm. The development of hand-held ultrasound devices facilitated the introduction of FAST into prehospital trauma management. It was demonstrated that prehospital FAST (p-FAST) can be performed with high sensitivity and specificity, and can lead to significant changes in prehospital trauma therapy and management. Standardized training with both theoretical and hands-on modules is mandatory in order to gain the skills required to perform FAST or p-FAST well.

Free fluid in Morison's pouch on bedside ultrasound predicts need for operative intervention in suspected ectopic pregnancy

BACKGROUND

Ectopic pregnancies are frequently present in women who present to the emergency department with pregnancy and abdominal pain or bleeding, a subset of whom may require operative intervention.

OBJECTIVES

To prospectively determine if emergency physician (EP)-performed transabdominal pelvic ultrasonography (US) with determination of free abdominal fluid in the hepatorenal space predicted the need for operative intervention.

METHODS

Patients who were suspected to have an ectopic pregnancy were prospectively enrolled over a ten-month period. An EP-performed bedside transabdominal pelvic US that included a view of the hepatorenal space (Morison's pouch) for free fluid. The EP US was classified as intrauterine pregnancy (IUP) or no definitive IUP, with Morison's pouch classified as positive or negative. The majority of patients had a subsequent transvaginal pelvic US performed by the Department of Radiology. Patients were followed up for radiology results, need for operative intervention, and ultimate outcome of the pregnancy.

RESULTS

There were 242 patients enrolled, with an average time to complete the EP US of 4 minutes and 27 seconds. There were 28 ectopic pregnancies diagnosed (11.6%), of which 18 patients underwent operative intervention. Free fluid in Morison's pouch was identified in ten patients, nine of whom underwent operative intervention, yielding a positive likelihood ratio of 112 (95% confidence interval = 15 to 831) for patients with suspected ectopic pregnancy who required operative intervention.

CONCLUSIONS

Free intraperitoneal fluid found in Morison's pouch in patients with suspected ectopic pregnancy may be rapidly identified at the bedside by EP-performed US and predicts the need for operative intervention.

Portable ultrasound in pre-hospital emergencies: a feasibility study

BACKGROUND

Ultrasound plays a central role in the evaluation of both trauma and medical emergencies. The development of portable sonography devices could extent its application into the pre-hospital arena. The aim of our study was to evaluate feasibility of pre-hospital ultrasound in the Norwegian Air Rescue setting.

MATERIAL AND METHODS

During a 3-month period, we conducted a prospective study using sonography in pre-hospital patient management. All examinations were carried out by the same ultrasound-certified physician using a Primedic Handyscan in a standardized focused protocol for abdominal and lung sonography and a subcostal 2-chamber long axis view. Inclusion criteria were abdominal/thoracic and obstetric trauma, circulatory/respiratory compromise, pulseless electric activity (PEA) in cardiac arrest, acute abdomen and monitoring during transport. Allowed examination time was restricted to 3 min on the scene. The patient's gender, age, symptoms, trauma mechanism, quality of visualization and diagnose made were recorded. Pre-hospital results were compared with in-hospital findings.

RESULTS

Thirty-eight patients were entered into the study. Three patients had to be excluded due to technical difficulties. Nineteen medical, 15 traumas and 1 obstetric patient were included. Good visualization was obtained in 74% (n= 26), moderate in 26% (n = 9). Median examination time was 2.5 min (range 1-3 min). Nine patients (26%) showed positive sonography findings. Sensitivity was 90%, specificity 96%. Diagnostic usefulness was high in undetermined cardiac arrest and hypotension and massive hematoperitoneum.

CONCLUSION

Pre-hospital ultrasound when applied by an proficient examiner using a goal-directed, time sensitive protocol is feasible, does not delay patient management and provides diagnostic and therapeutic benefit. Further studies are warranted to identify the exact indications and role of pre-hospital sonography.

Prehospital ultrasound imaging improves management of abdominal trauma

BACKGROUND

Blunt abdominal trauma with intra-abdominal bleeding is often underdiagnosed or even overlooked at trauma scenes. The purpose of this prospective, multicentre study was to compare the accuracy of physical examination and prehospital focused abdominal sonography for trauma (PFAST) to detect abdominal bleeding.

METHODS

Six rescue centres took part in the study from December 2002 to December 2003, including 230 patients with suspected abdominal injury. The accuracy of physical examination at the scene and PFAST were compared. Later examinations in the emergency department (ultrasonography and/or computed tomography) were used as the reference standard.

RESULTS

The complete protocol and follow-up was obtained in 202 patients. The sensitivity, specificity and accuracy of PFAST were 93 per cent, 99 per cent and 99 per cent, respectively, compared with 93 per cent, 52 per cent and 57 per cent for physical examination at the scene. Scanning with PFAST occurred a mean(s.d.) 35(13) min earlier than ultrasound in the emergency department. Abdominal bleeding was detected in 14 per cent of patients. Using PFAST led to a change in either prehospital therapy or management in 30 per cent of patients, and a change to admitting hospital in 22 per cent.

CONCLUSION

In this study, PFAST was a useful and reliable diagnostic tool when used as part of surgical triage at the trauma scene.

Sonographic measurement of the inferior vena cava as a marker of blood loss

Detecting and monitoring blood loss in trauma patients can often be challenging when an obvious source of hemorrhage is not readily seen.

OBJECTIVE

To provide a noninvasive measurement of circulating blood volume and of drop therein by measuring the change in the inferior vena cava diameter (IVCd) in relationship to blood loss.

METHODS

This was a prospective observational study on blood donors at a donation center. The IVCd, both during inspiration (IVCi) and during expiration (IVCe), was measured in volunteers both before and after blood donation of 450 mL. All actual blood donors aged 18 years and older were eligible for enrollment. Persons who were younger than 18 years, who declined to participate in the study, or who did not meet blood center criteria for blood donation were excluded. All examinations were performed in the supine position with the ultrasound transducer placed in a subxyphoid location. Sagittal sections of the IVC behind the liver were imaged and the maximal diameter of the IVCe and the minimal diameter of the IVCi were measured. Statistical analysis included test for normality, paired t test, and correlation analysis.

RESULTS

A total of 31 volunteers (18 male) with a mean age of 49.5 years (range, 18-73) were studied. The mean IVCe before blood donation was 17.4 mm (95% CI, 15.2-19.7 mm) and after blood donation was 11.9 mm (95% CI, 10.3-13.6 mm). The mean IVCi before blood donation was 13.3 mm (95% CI, 11.3-15.3 mm), but after blood donation was 8.13 mm (95% CI, 6.7-9.6 mm). The difference between IVCe before and after blood donation (dIVCe) was 5.5 mm (95% CI, 4.3-6.3 mm) yielding a P < .0001. The difference between IVCi before and after donation (dIVCi) was 5.16 mm (95% CI, 4.2-5.9 mm) yielding a P < .0001. The dIVCe and the dIVCi were closely correlated ( r = 0.83). Similarly, the pre-IVCe correlated well to the post-IVCe ( r = 0.74) and the pre-IVCi correlated well to the post-IVCi ( r = 0.75).

CONCLUSIONS

Our data indicates that the measurement of the IVC diameter is a reliable indicator of blood loss, even in small amounts of 450 mL. On average, there was about a 5-mm decrease in both the IVCe and IVCi after donation of 450 mL of blood. The measurement of the IVCe may be an important addition to the ultrasonographic evaluation of trauma and other potentially volume-depleted patients.