Accuracy of abdominal ultrasound for the diagnosis of pneumoperitoneum in patients with acute abdominal pain: a pilot study

Progress in the Application of Portable Ultrasound Combined with Artificial Intelligence in Pre-Hospital Emergency and Disaster Sites

With the miniaturization of ultrasound and the development of artificial intelligence, its application in disaster scenes and pre-hospital emergency care has become more and more common. This study summarizes the literature on portable ultrasound in pre-hospital emergency and disaster scene treatment in the past decade and reviews the development and application of portable ultrasound. Portable ultrasound diagnostic equipment can be used to diagnose abdominal bleeding, limb fracture, hemopneumothorax, pericardial effusion, etc., based on which trauma can be diagnosed pre-hospital and provide guiding suggestions for the next triage and rescue; in early rescue, portable ultrasound can guide emergency operations, such as tracheal intubation, pericardial cavity puncture, and thoracic and abdominal puncture as well as improve the accuracy and timeliness of operation techniques. In addition, with the development of artificial intelligence (AI), AI-assisted diagnosis can improve the diagnosis level of ultrasound at disaster sites. The portable ultrasound diagnosis system equipped with an AI robotic arm can maximize the pre-screening classification and fast and concise diagnosis and treatment of batch casualties, thus providing a reliable basis for batch casualty classification and evacuation at disaster accident sites.

Gastrointestinal Ultrasound in Emergency Setting

Acute bowel diseases are responsible for more than one third of subjects who were referred to the emergency department for acute abdominal pain and gastrointestinal evaluation. Gastrointestinal ultrasound (GIUS) is often employed as the first imaging method, with a good diagnostic accuracy in the setting of acute abdomen, and it can be an optimal diagnostic strategy in young females due to the radiation exposure related to X-ray and computed tomography methods. The physician can examine the gastrointestinal system in the area with the greatest tenderness by ultrasound, thus obtaining more information and data on the pathology than the standard physical examination. In this comprehensive review, we have reported the most relevant indications and advantages to using ultrasound in the investigation of abdominal acute pain.

Point-of-care Ultrasound of the Gastrointestinal Tract

The widespread use of portable ultrasound scanners has promoted the concept of point of care ultrasound (POCUS), namely "ultrasound performed bedside and interpreted directly by the clinician." The purpose of this short review is to outline how POCUS can be used in patients with diseases of the gastrointestinal (GI) tract. POCUS is not a replacement for comprehensive ultrasound, but rather allows physicians immediate access to clinical imaging for rapid diagnosis and efficient work-up and treatment of the patients. There are many indications for doing POCUS of the GI tract, including abdominal pain, diarrhea, palpable masses, and to detect fluid or free air in the abdominal cavity. To improve the visibility of deeper parts of the abdomen, the graded compression technique with the scan head is useful. During POCUS, the operator should look for signs of severe pathology including target lesions, the pseudo-kidney sign, the onion sign, dilated bowel loops, gastric retention, free fluid, and free air, depending on the actual clinical problem. We conclude that POCUS of the GI tract is very useful to provide a rapid diagnosis in many clinical scenarios.

The Use of Ceus Software with No Contrast Media Administration in the Diagnosis of Pneumoperitoneum

Background: Pneumoperitoneum is defined by the presence of free air in the abdominal cavity; gastrointestinal perforation is an important cause of this pathological condition. In emergency situations, radiology is considered vital in the early detection and identification of the site and cause of the perforation, which is critical for proper surgical planning. Aim: The aim of our study was to evaluate a new diagnostic US tool, based on the US contrast-specific software generally used during contrast-enhanced US examination (CEUS), without the administration of sonographic contrast media, and to describe the specific imaging features in the detection of free intra-peritoneal air. Subjects and Methods: One hundred and fifty-seven consecutive and hemodynamically stable patients, who arrived in our E.D. with an acute abdomen between April 2018 and October 2019, underwent US and CT examination, performed by three radiologists (with 5, 5, and 25 years of experience). The US was performed first and divided into two steps, using B-mode US and both B-mode and contrast-specific software US, with no contrast media administration. All the patients underwent CT examination. Results: In 32 out of 157 patients, the surgery confirmed GI perforation. CT correctly detected 31 out of 32 patients; the contrast-specific software US identified 30 perforated patients. CT reached a sensitivity value of 97% and specificity value of 100%; contrast-specific software US demonstrated higher values than B-mode US in sensitivity (93% vs. 70%, respectively) and specificity (98% vs. 88%, respectively). Conclusion: the use of contrast-specific software in emergencies improves image quality, and reaches higher levels of sensitivity and specificity with no time delay compared to standard US examination, helping radiologists expedite diagnoses.

Pneumoperitoneum as an uncommon complication after an axillary laceration in a horse

Lacerations of the axillary region occur frequently in horses. Typical complications caused by entrapment of air in the wound during locomotion are subcutaneous emphysema, with consecutive pneumomediastinum and pneumothorax. In this case report, the clinical, radiographic and laboratory diagnosis and management of these complications after an axillary laceration that finally resulted in pneumoperitoneum are described. A 1-year-old Hannoveranian was presented with a pre-existing axillary laceration of unknown duration and subcutaneous emphysema in the surrounding tissue. Due to extensive tissue loss, attempts to adequately close the wound surgically and by packing with sterile dressing material were unsuccessful. Despite stall confinement and tying of the horse, subcutaneous emphysema was progressive and pneumomediastinum as well as pneumothorax was developed. These complications were monitored radiographically. On day 5 after admission, signs of air accumulation were detected on radiographs craniodorsally in the peritoneum and a pneumoperitoneum was diagnosed. Repeated thoracentesis with a teat cannula to gradually evacuate the thoracic cavity was used in combination with nasal oxygen insufflation to treat global respiratory insufficiency. Subcutaneous emphysema and all other complications resolved progressively and the horse was discharged from the hospital 21 days after admission when the axillary wound was adequately filled with granulation tissue. The wound healed fully 1 month later and the horse did not develop long-term complications within the following year. To the authors´ knowledge, the development of pneumoperitoneum including its radiographic monitoring following an axillary laceration has not been described in horses previously.

'Diagnosis of Boerhaave's Syndrome With Aid of Bedside Ultrasound

BACKGROUND

Boerhaave's syndrome is characterized by transmural rupture of the distal esophagus in the setting of increased intraluminal pressures combined with negative intrathoracic pressure. It is a rare condition with high mortality (20-50% mortality rate).

CASE REPORT

This is a case of a 47-year-old man who appeared acutely ill, presenting with shortness of breath, chest and abdominal pain, and diagnosed with Boerhaave's syndrome with the assistance of bedside ultrasound. WHY SHOULD AN EMERGENCY PHYSICIANS BE AWARE OF THIS?: Emergency physicians must have a heightened suspicion of this diagnosis in patients presenting with chest and abdominal pain and can use bedside ultrasound skills to aid with diagnosis.

Bowel ultrasonography in acute abdomen: beyond acute appendicitis

Acute abdomen is a common reason for consultation in the emergency department. A broad spectrum of entities, including diverse diseases of the gastrointestinal tract, can cause acute abdomen. Although computed tomography is the technique most widely used to evaluate acute abdomen in the emergency department, abdominal ultrasound is often performed first and allows bowel disease to be suspected. This article describes the ultrasound features of diverse bowel diseases that can cause acute abdomen, such as acute diverticulitis, bowel obstruction, gastrointestinal perforation, bowel ischemia, intraabdominal fat necrosis, and miscellaneous processes such as endometriosis, foreign bodies, or vasculitis. Radiologists must be familiar with the different features of abnormal bowel that can be detected incidentally in patients without clinical suspicion of bowel disease. This article focuses on ultrasonographic signs of bowel disease; other articles in this series cover the ultrasonographic signs of acute appendicitis, inflammatory bowel disease, and infectious diseases.

Diagnosis at gut point: rapid identification of pneumoperitoneum via point-of-care ultrasound

Undifferentiated abdominal pain is a common presentation often requiring immediate medical or surgical intervention. Providing an accurate diagnosis involves a detailed patient history and thorough physical exam. Point of care ultrasound is gaining acceptance as a rapid diagnostic tool that can be used to accurately detect life-threatening conditions while potentially avoiding unnecessary radiation exposure and facilitating rapid treatment. Detection of pneumoperitoneum with point-of-care ultrasound is a simple procedure that relies heavily on the experience of the investigating practitioner. Standard technique involves placing a high-frequency linear-array transducer in the right upper quadrant, where abdominal free air is most likely to accumulate. Detection of the ‘gut point’, which is the transition of abdominal wall sliding to lack thereof in a single image, is the pathognomonic finding of pneumoperitoneum. If visualization is difficult, moving the patient to the left lateral decubitus position or using the scissors technique can provide additional image views. This representative case report and review highlights the use of abdominal POCUS for the diagnosis of pneumoperitoneum. Ultrasound should continue to be explored by clinicians to narrow the differential diagnosis of acute abdominal pain.

Gastrointestinal Ultrasound (GIUS) in Intestinal Emergencies - An EFSUMB Position Paper

An interdisciplinary group of European experts summarizes the value of gastrointestinal ultrasound (GIUS) in the management of three time-critical causes of acute abdomen: bowel obstruction, gastrointestinal perforation and acute ischemic bowel disease. Based on an extensive literature review, statements for a targeted diagnostic strategy in these intestinal emergencies are presented. GIUS is best established in case of small bowel obstruction. Metanalyses and prospective studies showed a sensitivity and specificity comparable to that of computed tomography (CT) and superior to plain X-ray. GIUS may save time and radiation exposure and has the advantage of displaying bowel function directly. Gastrointestinal perforation is more challenging for less experienced investigators. Although GIUS in experienced hands has a relatively high sensitivity to establish a correct diagnosis, CT is the most sensitive method in this situation. The spectrum of intestinal ischemia ranges from self-limited ischemic colitis to fatal intestinal infarction. In acute arterial mesenteric ischemia, GIUS may provide information, but prompt CT angiography is the gold standard. On the other end of the spectrum, ischemic colitis shows typical ultrasound features that allow correct diagnosis. GIUS here has a diagnostic performance similar to CT and helps to differentiate mild from severe ischemic colitis.

Ultrasound Findings Aid Decisions to Repair Partial Articular Supraspinatus Tendon Avulsion

OBJECTIVES

Ultrasound (US) is useful for diagnosing full-thickness rotator cuff tears and high-grade partial-thickness bursal-side tears. However, anisotropy artifacts make it difficult to identify partial articular supraspinatus tendon avulsion (PASTA) by US. This study was performed to determine the diagnostic accuracy of US for PASTA and to uncover sensitive findings that could aid decisions to repair.

METHODS

Patients who underwent preoperative US examinations and supraspinatus tendon confirmation by arthroscopic examinations were enrolled. We analyzed 52 PASTA cases involving greater than 50% thickness of the tendon and 52 age- and sex-matched cases with an intact supraspinatus. Two orthopedic surgeons blinded to the diagnosis interpreted US videos of the supraspinatus tendon. Six findings (echo defect, tendon delamination, echo change, tendon thickness, tendon fiber pattern, and cartilage interface sign) were assessed. We calculated the sensitivity, specificity, and accuracy for each US finding.

RESULTS

The cases consisted of 46 men and 58 women. The US diagnosis of PASTA showed sensitivity of 64.7%, specificity of 94.1%, and accuracy of 79.4%. The echo change in the short axis showed the highest sensitivity. Thinning and delamination showed the highest specificity of 100%. In contrast to previous reports, the sensitivity of the cartilage interface sign was low in both long-axis images (17.6%) and short-axis images (29.4%).

CONCLUSIONS

Preoperative diagnostic US to aid decisions regarding PASTA repair showed high specificity (94.1%) and moderate accuracy (79.4%). However, the sensitivity was only 64.7% and was affected by the examiner's experience with US.

Detecting Pneumoperitoneum via Point-of-Care Abdominal Ultrasound: To See Beyond Touch

Point-of-care ultrasound is increasingly important in the management of acute medical emergencies. An elderly man was brought to the emergency department after 2 days of fever and urinary retention. He was drowsy and had peri-arrest arrhythmia. He was hypoperfused peripherally with a systolic blood pressure of 45 mmHg and so was managed as for septic shock with no obvious aetiology. Chest and abdominal physical examinations were unremarkable. The source of sepsis was unclear. A point-of-care abdominal ultrasound was performed by the reviewing internist which detected a pneumoperitoneum, leading to a change in diagnosis to a perforated viscus which was confirmed later by a CT of the abdomen and pelvis.

Nonsurgical management of traumatic pneumoperitoneum in a cat

OBJECTIVE

To describe the nonsurgical management of a cat with traumatic pneumoperitoneum.

CASE SERIES SUMMARY

A 4-year-old cat was presented following vehicular polytrauma. Thoracic radiographs revealed 4 rib fractures, a scapular fracture, and pneumothorax. Abdominal ultrasound revealed a small volume of free abdominal fluid. Computed tomography showed a mild pneumoretroperitoneum and a pneumoperitoneum in the region of the porta hepatis. The cat was managed conservatively with close monitoring. Exploratory laparotomy was not pursued given patient stability and static serial imaging studies revealing no indications for surgical intervention. After 6 days, the pneumoperitoneum was no longer detectable.

NEW OR UNIQUE INFORMATION PROVIDED

To the authors' knowledge, this is the first report of successful nonsurgical management of traumatic pneumoperitoneum in a cat.

The value of ultrasound in diagnosis of pneumoperitoneum in emergent or critical conditions: A meta-analysis

Background:

Hollow organs perforation is a life-threatening condition. Early diagnosis and emergent intervention are important. Bedside ultrasound may be an alternative diagnostic tool for this condition.

Objective:

The aim of this study was to explore the diagnostic value of ultrasound of pneumoperitoneum in emergent or critical conditions through meta-analysis.

Methods:

PubMed, EMBASE, and Cochrane Library were systematically searched for potential studies. Then, two reviewers performed the processes of study selection, data extraction, and quality assessment independently. Finally, diagnostic indexes were analyzed with STATA 12.0 software (Serial No. 40120519635).

Results:

A total of five studies with moderate to high quality were eligible for meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio and their 95% confidence interval were 0.91 (95% confidence interval = 0.86–0.94), 0.96 (95% confidence interval = 0.75–0.99), 22.05 (95% confidence interval = 3.10–156.96), and 0.10 (95% confidence interval = 0.07–0.15), respectively. The area under the summary receiver operating characteristic curve was 0.92 (95% confidence interval = 0.90–0.94).

Conclusion:

Abdominal ultrasound is a useful alternative tool in diagnosing of pneumoperitoneum. However, due to limited evidence, it is not yet indicated for routine clinical use.

ABCDE of prehospital ultrasonography: a narrative review

Prehospital point-of-care ultrasound used by nonradiologists in emergency medicine is gaining ground. It is feasible on-scene and during aeromedical transport and allows health-care professionals to detect or rule out potential harmful conditions. Consequently, it impacts decision-making in prioritizing care, selecting the best treatment, and the most suitable transport mode and destination. This increasing relevance of prehospital ultrasonography is due to advancements in ultrasound devices and related technology, and to a growing number of applications. This narrative review aims to present an overview of prehospital ultrasonography literature. The focus is on civilian emergency (trauma and non-trauma) setting. Current and potential future applications are discussed, structured according to the airway, breathing, circulation, disability, and environment/exposure (ABCDE) approach. Aside from diagnostic implementation and specific protocols, procedural guidance, therapeutic ultrasound, and challenges are reviewed.

A novel ultrasound scanning approach for evaluating femoral cartilage defects of the knee: comparison with routine magnetic resonance imaging

Background

This study aimed to assess a novel ultrasound (US) scanning approach in evaluating knee femoral cartilaginous defects, compared with magnetic resonance imaging (MRI, commonly used for knee imaging) and arthroscopy (gold standard).

Methods

Sixty-four consecutive patients (65 knees) were prospectively evaluated between April 2010 and July 2011.

Results

The overall sensitivity (62.2 and 69.4%), specificity (92.9 and 90.5%), accuracy (75.4 and 78.5%), and adjusted positive (88.7 and 90.4%) and negative predictive (69.5 and 73.3%) were similar for both radiologists (weighted κ = 0.76). Furthermore, agreement between grading by US and MRI was substantial (weighted κ = 0.61).

Conclusions

In conclusion, the novel US scanning approach allows similar diagnostic performance compared to routine MRI for knee cartilage defects. US is more accessible, easier to perform, and less expensive than MRI, with potential advantages of easier initial screening and assessment of cartilage defects.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0887-x) contains supplementary material, which is available to authorized users.

Ultrasound in acute internal medicine; time to set a European standard

Nowadays point-of-care ultrasound (POCUS) is considered indispensable for critical care and emergency physicians. POCUS is a noninvasive tool, can be done at the bedside, leads to instant diagnostic information and is safe in terms of radiation. POCUS could also be very suitable for internists in the field of acute internal medicine. There are differences between European internists in the use of POCUS from no use at all to more outlined educational programs. In literature there are examples of comprehensive POCUS guidelines which could serve as an example for the European Federation of Internal Medicine (EFIM). In this review some aspects of POCUS are highlighted and the authors encourage EFIM to set European standards for this important development.

Sonographic detection of pneumoperitoneum

Accurate and timely detection of a perforated hollow viscus is crucial and has profound consequences for the patient with an acute abdomen. While a CT scan can provide an accurate diagnosis, the increasingly indiscriminate use of this modality sparks concern regarding radiation dosing, its associated safety concerns and its timely occurrence. There are distinct and readily reproducible findings of pneumoperitoneum on ultrasound. However, sonographers should be trained to detect pneumoperitoneum or patients may be discharged with false-negative results. This case report supports such a view and investigates the current literature surrounding this issue.

Air and its Sonographic Appearance: Understanding the Artifacts

BACKGROUND

Although air has traditionally been considered a barrier to sonographic imaging, when encountered in unusual settings it can serve as an important indicator of various pathologic states as well. Clinician recognition and thorough understanding of the characteristic pattern of artifacts generated by air are critical for making a number of important diagnoses.

CASE SERIES

We present five emergency department cases in which air was visualized in a pathologic location. Pneumothorax, pneumoperitoneum, necrotizing fasciitis, or Fournier's gangrene, and subcutaneous emphysema and pneumomediastinum, can be rapidly and easily identified on ultrasound by the presence of air artifacts. The relevant sonographic findings are described and discussed in this article. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to its inherent impedance mismatch with other human tissues, air has a characteristic appearance on ultrasound that includes irregular hyperechoic structures, "dirty shadowing," A-lines, and decreased visualization of deeper structures. Knowledge of the sonographic appearance of air artifacts can assist the physician in making a diagnosis, selecting appropriate additional imaging, and enlisting specialist consultation.

Ultrasound findings in critical care patients: the "liver sign" and other abnormal abdominal air patterns

In critical care patients, point of care abdominal ultrasound examination, although it has been practiced for over 30 years, is not as widespread as its cardiac or pulmonary counterparts. We report two cases in which detection of air during abdominal ultrasound allowed the early detection of life-threatening pathologies. In the first case, a patient with severe Clostridium difficile was found to have portal venous gas but its significance was confounded by a recent surgery. Serial ultrasonographic exams triggered a surgical intervention. In the second case, we report what we call the "liver sign" a finding in patients with pneumoperitoneum. These findings, all obtained prior to conventional abdominal imaging, had immediate clinical impact and avoided unnecessary delays and radiation. Detection of abdominal air should be part of the routine-focused ultrasonographic exam and for critically ill patients an algorithm is proposed.

Manual vs. pressure-controlled facemask ventilation for anaesthetic induction in paralysed children: a randomised controlled trial

BACKGROUND

During anaesthetic induction with a facemask, the inconsistent inspiratory flow with manual ventilation (MV) raises the peak airway pressure (PAP), which can be significantly higher than PAP during pressure-controlled ventilation (PCV). In this study, PAP was compared between MV and PCV at the same tidal volume of 8-10 ml/kg during facemask ventilation for anaesthetic induction in children. The occurrence of gastric insufflation (GI) was evaluated with ultrasonography and stethoscopic auscultation.

METHODS

Forty-eight children, aged 0.5-7 years, undergoing elective urologic surgery were randomly allocated into either Group MV or Group PCV. Under light sedation with thiopental iv., ultrasonography (US) was performed and the gastric antrum was identified. After additional thiopental and rocuronium administration, facemask ventilation with a tidal volume of 8-10 ml/kg was performed for 3 min, whereas respiratory parameters were recorded at 1 min intervals. Real-time US and stethoscopic auscultation were performed for evaluation of GI.

RESULTS

In the MV group, PAP was higher at all the time points compared with the PCV group (14 vs. 9.5, 15 vs. 10 and 15 vs. 9 cmH2 O, all P < 0.05). However, there was no difference in the GI occurrence between Group MV and Group PCV (7 vs. 3, P = 0.284). There was no difference between PAP in patients with GI and without GI (P > 0.05). Ultrasonography was more sensitive in detecting GI than the stethoscopic auscultation (10 vs. 5). Gastric antral area was expanded after facemask ventilation in both groups, but there were no intergroup differences.

CONCLUSION

Although PCV provided lower PAP than MV at the same tidal volume, the risk of GI may not be eliminated during facemask ventilation in paralysed small children.