Chest radiography in the ICU: Part 2, Evaluation of cardiovascular lines and other devices

Cardiothoracic Medical Devices - A Pictorial Review

The rapid advancement of medical technology has introduced a plethora of innovative devices designed for use within the thoracic cavity. Familiarity with the characteristic imaging features of these devices, their purpose and desired positioning is crucial for radiologists to identify them promptly and accurately assess any associated complications. This pictorial review provides a comprehensive overview of the radiologic findings associated with various new chest devices, aiming to equip radiologists with the knowledge required for effective clinical management.

Analyzing Overlaid Foreign Objects in Chest X-rays-Clinical Significance and Artificial Intelligence Tools

The presence of non-biomedical foreign objects (NBFO), such as coins, buttons and jewelry, and biomedical foreign objects (BFO), such as medical tubes and devices in chest X-rays (CXRs), make accurate interpretation difficult, as they do not indicate known biological abnormalities like excess fluids, tuberculosis (TB) or cysts. Such foreign objects need to be detected, localized, categorized as either NBFO or BFO, and removed from CXR or highlighted in CXR for effective abnormality analysis. Very specifically, NBFOs can adversely impact the process, as typical machine learning algorithms would consider these objects to be biological abnormalities producing false-positive cases. It holds true for BFOs in CXRs. This paper examines detailed discussions on numerous clinical reports in addition to computer-aided detection (CADe) with diagnosis (CADx) tools, where both shallow learning and deep learning algorithms are applied. Our discussion reflects the importance of accurately detecting, isolating, classifying, and either removing or highlighting NBFOs and BFOs in CXRs by taking 29 peer-reviewed research reports and articles into account.

Imaging in the Intensive Care Unit

Radiology plays an important role in the management of the most seriously ill patients in the hospital. Over the years, continued advances in imaging technology have contributed to an improvement in patient care. However, even with such advances, the portable chest radiograph (CXR) remains one of the most commonly requested radiographic examinations. While they provide valuable information, CXRs remain relatively insensitive at revealing abnormalities and are often nonspecific. Chest computed tomography (CT) can display findings that are occult on CXR and is particularly useful at identifying and characterizing pleural effusions, detecting barotrauma including small pneumothoraces, distinguishing pneumonia from atelectasis, and revealing unsuspected or additional abnormalities which could result in increased morbidity and mortality if left untreated. CT pulmonary angiography is the modality of choice in the evaluation of pulmonary emboli which can complicate the hospital course of the ICU patient. This article will provide guidance for interpretation of CXR and thoracic CT images, discuss some of the invasive devices routinely used, and review the radiologic manifestations of common pathologic disease states encountered in ICU patients. In addition, imaging findings and complications of more specific clinical scenarios in which the incidence has increased in the ICU setting, such as patients who are immunocompromised, have interstitial lung disease, or COVID-19, will also be discussed. Communication between the radiologist and intensivist, particularly on complicated cases, is important to help increase diagnostic accuracy and leads to an improvement in the management of the most critically ill patients.

The undulating line sign and other more common pediatric central catheter malpositions

Central venous and arterial catheters are among the most commonly assessed support devices by radiologists. The position of these catheters must be carefully assessed to ensure proper placement, as malpositioning may lead to life-threatening consequences. Therefore, it is important for radiologists to understand the anatomy of the central vessels and the expected location of catheters. While this can be difficult in small children and especially in neonates, knowledge of the expected course and ideal termination of catheters allows for recognition of a malpositioned line, which may be unsuspected clinically. The purpose of this article is to discuss appropriate positioning of central catheters in pediatric patients, focusing primarily on venous catheters. We also propose a new radiographic sign to recognize, the undulating line sign, as an indication of an inappropriate course of a newly placed venous catheter.

Chest X-ray in intensive care unit patients: what there is to know about thoracic devices

Critically ill patients admitted to the intensive care unit require continuous monitoring of vital functions as well as mechanical and pharmacological support, provided through different devices. Chest radiographs play a fundamental role in monitoring the conditions of these patients and assessing the intensive-care devices after their insertion; therefore, the radiologist needs to know their normal appearance and their correct position and should be aware of the possible complications that may occur after their placement. This pictorial review illustrates the radiographic appearance of non-cardiological devices commonly used in clinical practice (central venous catheters, tunneled catheters, Swan-Ganz catheters, chest tubes, endotracheal tubes, and nasogastric tubes), their correct position and the most common complications that may occur after their placement.

Malpositioned Lines and Tubes on Chest Radiograph – A Concise Pictorial Review

A wide variety of cardiothoracic support devices are used in intensive care units and few of these devices are increasingly being utilized in outpatient settings as well. A meticulous assessment of these lines and tubes by the interpreting radiologist is cardinal since malpositioned lines and tubes can significantly impact the functioning of these devices and may result in potential complications affecting the clinical outcomes. The purpose of this article is to illustrate the normal positioning and malpositioning of the routinely used support lines and tubes identified on chest radiographs.

The cardiothoracic ratio: a neglected preoperative risk-stratified method for patients with rheumatic heart disease undergoing valve replacement surgery

OBJECTIVES

It is common for patients with rheumatic heart disease to have an enlarged heart. We investigated the prognostic value of cardiothoracic ratio (CTR) in patients with rheumatic heart disease undergoing valve replacement surgery.

METHODS

A total of 1772 patients were divided into 4 groups based on the quartiles of preoperative CTR: <0.56 (n = 349), 0.56-0.61 (n = 488), 0.61-0.66 (n = 449) and ≥0.66 (n = 486). The CTR was measured from postero-anterior chest radiographs. We then investigated the association between the CTR and adverse outcomes.

RESULTS

In-hospital mortality was 4.0% (71/1772). Analyses of receiver operating characteristic curves showed that, at a cut-off of 0.6, the CTR exhibited 66.2% sensitivity and 64.0% specificity for detecting in-hospital death (area under curve 0.671, P < 0.001). The prevalence of in-hospital death was 7.1% in males with a CTR >0.6, which was significantly higher in males without a CTR. A similar result was observed in females (1.9 vs 5.1%, P = 0.004). Multivariable regression showed that a CTR >0.6 was an independent predictor of in-hospital (odds ratio 2.36, P = 0.005) and 1-year mortality (hazard ratio 2.06, P = 0.006). Kaplan-Meier curves, for the cumulative rate of 1-year mortality among groups, indicated that the risk of death was increased if the CTR >0.6 (log-rank 16.36, P < 0.001).

CONCLUSIONS

CTR, as a simple and reproducible indicator, was identified as a prognostic factor for predicting poor outcomes in patients with rheumatic heart disease undergoing valve replacement surgery.

Imaging of Cardiac Support Devices

Patients hospitalized in the intensive care unit (ICU) often have multiple support lines and devices that need routine imaging evaluation by radiologists. In patients with cardiogenic shock or depressed cardiac function, mechanical circulation support devices are used in combination with medical therapies to improve patient outcomes and sometimes can stabilize patients for surgical intervention. This article discusses some of the more commonly encountered mechanical circulation devices seen in ICU patients, including intra-aortic balloon pumps, Impella devices, extracorporeal membrane oxygenation cannulas, and ventricular assist devices. Normal appearance and commonly encountered device-related complications that can be diagnosed on imaging are reviewed.

Chest radiographs of cardiac devices (Part 1): Cardiovascular implantable electronic devices, cardiac valve prostheses and Amplatzer occluder devices

Several new innovative cardiac devices have been created over the last few decades. Chest radiographs (CXRs) are the most common imaging investigations undertaken because of their value in evaluating the cardiorespiratory system. It is important for the interpreting radiologist to not only identify these iatrogenic objects but also to assess for their accurate placement, as well as for any complications related to their placement, which may be seen either on the immediate post-procedural CXR or on a follow-up CXR.

Chest radiographs of cardiac devices (Part 1): Lines, tubes, non-cardiac medical devices and materials

Chest radiographs (CXRs) are the most common imaging investigations undertaken because of their value in evaluating the cardiorespiratory system. They play a vital role in intensive care units for evaluating the critically ill. It is therefore very common for the radiologist to encounter tubes, lines, medical devices and materials on a daily basis. It is important for the interpreting radiologist not only to identify these iatrogenic objects, but also to look for their accurate placement as well as for any complications related to their placement, which may be seen either on the immediate post-procedural CXR or on a follow-up CXR. In this article, we discussed and illustrated the routinely encountered tubes and lines that one may see on a CXR as well as some of their complications. In addition, we also provide a brief overview of other important non-cardiac medical devices and materials that may be seen on CXRs.

Imaging of ICU Patients

Imaging in intensive care unit (ICU) is integral to patient management. The portable chest radiograph is the most commonly requested imaging examination in ICU, and, despite its limitations, it significantly contributes to the decision-making process. Multidetector CT (MDCT) is reserved for relatively complex and challenging clinical scenarios. Bedside ultrasound is emerging as a promising imaging modality as it does not subject the patients to risks and resources involved in the transportation of these patients to the CT facility. Ultrasound is an effective modality to triage patients and is being increasingly incorporated into the emergency and intensive care management algorithms.

Can portable tomosynthesis improve the diagnostic value of bedside chest X-ray in the intensive care unit? A proof of concept study

Portable bedside chest X-ray (CXR) is an important and frequently used tool in the intensive care unit (ICU). Unfortunately, the diagnostic value of portable CXR is often low due to technical limitations and suboptimal patient positioning. Additionally, abnormalities in the chest may be hidden on the projection image by overlapping anatomy and devices such as endotracheal tubes, lines and catheters. Digital tomosynthesis (DTS) can solve the problem of anatomical overlap. In DTS, several low-dose X-ray images from different angles are acquired and subsequently used by a reconstruction algorithm to compute section images along planes parallel to the detector. However, a portable device to be used for portable bedside chest DTS is not on the market yet. In this work, we discuss modifications to a portable X-ray device to enable portable DTS and illustrate the potential of portable DTS to improve the diagnostic value of bedside CXR in the ICU. A simulation, based on computed tomography scans, is presented. Our experiments comparing portable DTS with conventional bedside CXR showed a substantially improved detection of pneumothorax and other abnormalities.

Evaluation of medical devices in thoracic radiograms in intensive care unit - time to pay attention!

Objective

To identify and evaluate the correct positioning of the most commonly used medical devices as visualized in thoracic radiograms of patients in the intensive care unit of our center.

Methods

A literature search was conducted for the criteria used to evaluate the correct positioning of medical devices on thoracic radiograms. All the thoracic radiograms performed in the intensive care unit of our center over an 18-month period were analyzed. All admissions in which at least one thoracic radiogram was performed in the intensive care unit and in which at least one medical device was identifiable in the thoracic radiogram were included. One radiogram per admission was selected for analysis. The radiograms were evaluated by an independent observer.

Results

Out of the 2,312 thoracic radiograms analyzed, 568 were included in this study. Several medical devices were identified, including monitoring leads, endotracheal and tracheostomy tubes, central venous catheters, pacemakers and prosthetic cardiac valves. Of the central venous catheters that were identified, 33.6% of the subclavian and 23.8% of the jugular were malpositioned. Of the endotracheal tubes, 19.9% were malpositioned, while all the tracheostomy tubes were correctly positioned.

Conclusion

Malpositioning of central venous catheters and endotracheal tubes is frequently identified in radiograms of patients in an intensive care unit. This is relevant because malpositioned devices may be related to adverse events. In future studies, an association between malpositioning and adverse events should be investigated.

Central Venous Catheter Intravascular Malpositioning: Causes, Prevention, Diagnosis, and Correction

Despite the level of skill of the operator and the use of ultrasound guidance, central venous catheter (CVC) placement can result in CVC malpositioning, an unintended placement of the catheter tip in an inadequate vessel. CVC malpositioning is not a complication of central line insertion; however, undiagnosed CVC malpositioning can be associated with significant morbidity and mortality. The objectives of this review were to describe factors associated with intravascular malpositioning of CVCs inserted via the neck and chest and to offer ways of preventing, identifying, and correcting such malpositioning. A literature search of PubMed, Cochrane Library, and MD Consult was performed in June 2014. By searching for “Central line malposition” and then for “Central venous catheters intravascular malposition,” we found 178 articles written in English. Of those, we found that 39 were relevant to our objectives and included them in our review. According to those articles, intravascular CVC malpositioning is associated with the presence of congenital and acquired anatomical variants, catheter insertion in left thoracic venous system, inappropriate bevel orientation upon needle insertion, and patient’s body habitus variants. Although plain chest radiography is the standard imaging modality for confirming catheter tip location, signs and symptoms of CVC malpositioning even in presence of normal or inconclusive conventional radiography findings should prompt the use of additional diagnostic methods to confirm or rule out CVC malpositioning. With very few exceptions, the recommendation in cases of intravascular CVC malpositioning is to remove and relocate the catheter. Knowing the mechanisms of CVC malpositioning and how to prevent, identify, and correct CVC malpositioning could decrease harm to patients with this condition.

The role of early postmortem CT in the evaluation of support-line misplacement in patients with severe trauma

OBJECTIVE

The purpose of this study was to retrospectively assess the role of early postmortem CT in evaluating support-line misplacement to improve future treatment in the trauma setting.

MATERIALS AND METHODS

We included all postmortem CT examinations that were performed for trauma patients within the 1st hour after declaration of death in our tertiary medical center between August 1, 2008, and August 31, 2013. Correct placement of the following support lines was evaluated: endotracheal tubes (ETTs), chest drains, central venous catheters (CVCs), and nasogastric tubes (NGTs). Prehospital resuscitation efforts were started in all cases.

RESULTS

Early postmortem CT was performed on average 22 minutes after declaration of death in 25 consecutive patients with severe trauma. Overall, 14 subjects (56%) had suboptimal or misplaced support lines. Of ETTs inserted into 18 trauma victims; three (17%) were mislaid in the right main bronchus and five (28%) were near or at the level of the carina. Of chest drains inserted into 13 subjects, 10 were suboptimally positioned (77%). Of CVCs inserted into eight subjects (seven femoral and one brachiocephalic), one femoral CVC (13%) was malpositioned in the soft tissues of the pelvis. Of NGTs inserted in five trauma victims, one was folded within the pharynx.

CONCLUSION

Early postmortem CT for patients who have experienced severe poly-trauma can be of important educational value to radiologists and the trauma teams, providing immediate feedback regarding the location of the support lines and possibly contributing to improved training and command of the learning curve by medical staff.

Is routine chest X-ray after surgical and percutaneous tracheostomy necessary in adults: a systemic review of the current literature

BACKGROUND

For many years, routine post-tracheostomy chest X-ray has been the standard of care for patients in many countries. However, recent evidence suggests that this is unnecessary and cost-ineffective.

OBJECTIVE

To review the current literature and examine the role of routine post-tracheostomy chest X-ray in adult patients.

TYPE OF REVIEW

Systemic review.

SEARCH STRATEGY

Electronic databases (PubMed, EMBASE, Cochrane) were searched using the keywords 'chest X-ray/radiography/radiograph' and 'tracheostomy/tracheotomy' in various permutations. Search period ranged from 1960 to 2012. Inclusion criteria included systematic reviews, meta-analyses, randomised control trials, prospective and retrospective case series. Paediatric and non-English articles were excluded. Abstracts and subsequently full text articles were screened by two of the authors independently. References from obtained articles were also examined.

EVALUATION METHOD

Specific outcome measures were collated to evaluate the usefulness of post-tracheostomy chest X-ray: Chest X-ray detected (tracheostomy-related) complication rates Proportion of cases requiring significant intervention Potential predictors of complications

RESULTS

Routine post-tracheostomy chest X-ray is of a low yield, and its findings had limited impact on patient management. Complication detection rates for surgical and percutaneous tracheostomy are 2.2% and 3.2%, respectively. Only 0.7% and 1.8% of chest X-rays performed in surgical and percutaneous tracheostomy cases, respectively, required intervention. Certain groups of patients, however, are at higher risks of complications, and may benefit from post-tracheostomy chest X-ray. For surgical tracheostomy, these groups include those with post-operative signs and symptoms of complications or had emergent or 'difficult' tracheostomies. For percutaneous tracheostomy, high-risk patients include trauma cases (unspecified), patients with post-procedural signs and symptoms of complications, patients who have high ventilatory requirements, difficult tracheostomy cases or tracheostomy cases performed without bronchoscopic guidance.

CONCLUSION

The practice of routine post-tracheostomy chest X-ray is debatable owing to its low yield and minimal impact on clinical management. However, certain groups of patients appear to be at higher risks of post-tracheostomy complications; currently, there is insufficient evidence to conclude the absolute need for routine chest X-ray in these groups of patients, although it may be prudent to do so based on available evidence in the literature and logical clinical reasoning.