Radiation Exposure in the Medical ICU: Predictors and Characteristics

Computed Tomography Effective Dose and Image Quality in Deep Learning Image Reconstruction in Intensive Care Patients Compared to Iterative Algorithms

Deep learning image reconstruction (DLIR) algorithms employ convolutional neural networks (CNNs) for CT image reconstruction to produce CT images with a very low noise level, even at a low radiation dose. The aim of this study was to assess whether the DLIR algorithm reduces the CT effective dose (ED) and improves CT image quality in comparison with filtered back projection (FBP) and iterative reconstruction (IR) algorithms in intensive care unit (ICU) patients. We identified all consecutive patients referred to the ICU of a single hospital who underwent at least two consecutive chest and/or abdominal contrast-enhanced CT scans within a time period of 30 days using DLIR and subsequently the FBP or IR algorithm (Advanced Modeled Iterative Reconstruction [ADMIRE] model-based algorithm or Adaptive Iterative Dose Reduction 3D [AIDR 3D] hybrid algorithm) for CT image reconstruction. The radiation ED, noise level, and signal-to-noise ratio (SNR) were compared between the different CT scanners. The non-parametric Wilcoxon test was used for statistical comparison. Statistical significance was set at p < 0.05. A total of 83 patients (mean age, 59 ± 15 years [standard deviation]; 56 men) were included. DLIR vs. FBP reduced the ED (18.45 ± 13.16 mSv vs. 22.06 ± 9.55 mSv, p < 0.05), while DLIR vs. FBP and vs. ADMIRE and AIDR 3D IR algorithms reduced image noise (8.45 ± 3.24 vs. 14.85 ± 2.73 vs. 14.77 ± 32.77 and 11.17 ± 32.77, p < 0.05) and increased the SNR (11.53 ± 9.28 vs. 3.99 ± 1.23 vs. 5.84 ± 2.74 and 3.58 ± 2.74, p < 0.05). CT scanners employing DLIR improved the SNR compared to CT scanners using FBP or IR algorithms in ICU patients despite maintaining a reduced ED.

Alleviation of Splenic Injury by CB001 after Low-Dose Irradiation Mediated by NLRP3/Caspase-1-BAX/Caspase-3 Axis

Low-dose radiation has been extensively employed in clinical practice, including tumor immunotherapy, chronic inflammation treatment and nidus screening. However, the damage on the spleen caused by low-dose radiation significantly increases the risk of late infection-related mortality, and there is currently no corresponding protective strategy. In the present study, a novel compound preparation named CB001 mainly constituted of Acanthopanax senticosus (AS) and Oldenlandia diffusa (OD) was developed to alleviate splenic injury caused by fractionated low-dose exposures. As our results show that, white pulp atrophy and the excessive apoptosis in spleen tissue induced by radiation exposure were significantly ameliorated by CB001. Mechanistically, BAX-caspase-3 signaling and nucleotide-binding domain and leucine-rich-repeat-containing family pyrin 3 (NLRP3) inflammasome signaling were demonstrated to be involved in the radio-protective activity of CB001 with the selective activators. Furthermore, the crosstalk between apoptosis signaling and NLRP3 inflammasome signaling in mediating the radio-protective activity of CB001 was clarified, in which the pro-apoptotic protein BAX but not the anti-apoptotic protein Bcl2 was found to be downstream of NLRP3. Our study demonstrated that the use of a novel drug product CB001 can potentially facilitate the alleviation of radiation-induced splenic injury for patients receiving medical imaging diagnosis or fractionated radiation therapy.

Radiation Overuse in Intensive Care Units

Radiological imaging is essential for acute patient management in Intensive Care Units (ICUs); however, it introduces the risk of exposure to ionizing radiation. This review synthesizes research on radiation exposure in ICU settings, highlighting its rise during the COVID-19 pandemic and the rise in repetitive imaging. Our analysis extends to radiation safety thresholds, revealing that some ICU patients exceed the diagnostic reference level, emphasizing the need to balance diagnostic utility against potential long-term risks, such as cancer. Prospective studies have demonstrated an increase in the median cumulative effective dose in patients with trauma over time, prompting calls for improved awareness and monitoring. Moreover, innovative dose-reduction strategies and optimized protocols, especially in neuro-ICUs, promise to mitigate these risks. This review highlights the essential but risky role of radiological imaging in critical care. It advocates for rigorous radiation management protocols to safeguard patient health while ensuring the continuity of high-quality medical care.

Diagnostic Yield, Radiation Exposure, and the Role of Clinical Decision Rules to Limit Computed Tomographic Pulmonary Angiography-Associated Complications

OBJECTIVES

Computed tomographic pulmonary angiography (CT-PA) is associated with significant cost, contrast, and radiation exposure. Clinical decision rules (CDRs) reduce the need for diagnostic imaging; however, their utility in the medical intensive care unit (MICU) remains unknown. We explored the diagnostic yield and complications associated with CT-PA (radiation exposure and contrast-induced acute kidney injury [AKI]) while investigating the efficacy of CDRs to reduce unnecessary testing.

METHODS

All CT-PAs performed in an academic MICU for 4 years were retrospectively reviewed. The Wells and revised Geneva scores (CDRs) and radiation dose per CT-PA were calculated, and the incidence of post-CT-PA AKI was recorded.

RESULTS

A total of 439 studies were analyzed; the diagnostic yield was 11% (48 PEs). Positive CT-PAs were associated with a higher Wells score (5.8 versus 3.2, P < 0.001), but similar revised Geneva scores (6.4 versus 6.0, P = 0.32). A Wells score of ≥4 had a positive likelihood ratio of 2.1 with a negative predictive value of 98.2. More than half (88.9%) of patients with a Wells score of ≤4 developed an AKI, with 55.6% of those having recovery of renal function.

CONCLUSIONS

There is overutilization of CT-PA in the MICU. The Wells score retains its negative predictive value in critically ill adult patients and may aid to limit radiation exposure and contrast-induced AKI in MICU.

Radiation Exposure in Extracorporeal Life Support

Extracorporeal membrane oxygenation (ECMO) exposes patients to multiple radiologic studies. We hypothesized ECMO patients endure radiation exposure in excess of the International Commission of Radiological Protection (ICRP) recommendations of cumulative effective dose (CED, >20 mSv and 5-year cumulative limit of CED >100 mSv). We conducted a retrospective observational study in an academic medical center between January 2016 and December 2018 involving adult admissions (N = 306) on ECMO. Ionizing radiation was calculated from reference values to determine CED. Approximately 9.4% (N = 29) patients accrued CED >50 mSv and 4.5% (N = 14) accrued CED >100 mSv during ECMO. Over the entire hospitalization, 28% (N = 85) accrued >50 mSv and 14.7% (N = 45) accrued CED >100 mSv. Median CED during ECMO was 2.3 mSv (IQR, -0.82 to 8.1 mSv), and the entire hospitalization was 17.4 mSv (IQR, -4.5 to 56.6 mSv). Thirteen percent of the median CED accrued during hospitalization could be attributed to ECMO. Longer hospitalization was associated with a higher CED (50 days [IQR, -25 to 76 days] in CED >50 vs. 19 days [IQR, -10 to 32 days] in CED <50). Computer tomography (CT) scans and interventional radiology (IR) procedures contributed to 43.8% and 44.86%, respectively, of CED accrued on ECMO and 52.2% and 37.1% of CED accumulated during the whole hospitalization. Guidelines aimed at mitigating radiation exposure are urgently needed.

Frequency and Results of Pregnancy Screening in Critically Ill Adolescents in Multiple Health Care Organizations

PURPOSE

Adolescent females may undergo pregnancy screening while receiving critical care services, but the frequency and results are unknown. The objectives of this study are to evaluate patient characteristics, pregnancy screening frequency, and rate of positive pregnancy screens in adolescent females of childbearing age who require critical care services. We hypothesize that when adolescent pregnancy screening is performed in the critical care setting, it occurs in a higher frequency in older subjects.

METHODS

This is a multicenter retrospective observational cohort study utilizing TriNetX, an electronic health record database. The following electronic health record data were collected and evaluated in adolescent females aged 12-18 years and billed for critical care services: age, race, ethnicity, diagnostic codes, selected radiology and surgical procedure codes, number of deaths, pregnancy screening laboratory codes, and pregnancy screening results.

RESULTS

A total of 5,241 subjects (2,242 [42.8%] subjects for whom pregnancy screen was noted and 2,999 [57.2%] subjects for whom it was not noted) were included in this study. Subjects aged 15-18 years (odds ratio = 1.56, 95% confidence interval = 1.38-1.77, p value < .0001) and had Hispanic or Latina ethnicity (odds ratio = 1.46, 95% confidence interval = 1.28-1.66, p value < .0001) had a higher association with pregnancy screening. A positive pregnancy screen was identified in 18 (0.8%) subjects.

DISCUSSION

In our study, positive pregnancy screens were infrequent, not all subjects were screened, and there was an association between pregnancy screening and ethnicity. Because of the potential for screening bias, this study suggests that clinicians should strongly consider routine pregnancy screening for all females of childbearing age and that hospital policies should require this type of screening.

Regional pleural strain measurements during mechanical ventilation using ultrasound elastography: A randomized, crossover, proof of concept physiologic study

Background

Mechanical ventilation is a common therapy in operating rooms and intensive care units. When ill-adapted, it can lead to ventilator-induced lung injury (VILI), which is associated with poor outcomes. Excessive regional pulmonary strain is thought to be a major mechanism responsible for VILI. Scarce bedside methods exist to measure regional pulmonary strain. We propose a novel way to measure regional pleural strain using ultrasound elastography. The objective of this study was to assess the feasibility and reliability of pleural strain measurement by ultrasound elastography and to determine if elastography parameters would correlate with varying tidal volumes.

Methods

A single-blind randomized crossover proof of concept study was conducted July to October 2017 at a tertiary care referral center. Ten patients requiring general anesthesia for elective surgery were recruited. After induction, patients received tidal volumes of 6, 8, 10, and 12 mL.kg^–1 in random order, while pleural ultrasound cineloops were acquired at 4 standardized locations. Ultrasound radiofrequency speckle tracking allowed computing various pleural translation, strain and shear components. We screened 6 elastography parameters (lateral translation, lateral absolute translation, lateral strain, lateral absolute strain, lateral absolute shear and Von Mises Strain) to identify those with the best dose-response with tidal volumes using linear mixed effect models. Goodness-of-fit was assessed by the coefficient of determination. Intraobserver, interobserver and test-retest reliability were calculated using intraclass correlation coefficients.

Results

Analysis was possible in 90.7% of ultrasound cineloops. Lateral absolute shear, lateral absolute strain and Von Mises strain varied significantly with tidal volume and offered the best dose-responses and data modeling fits. Point estimates for intraobserver reliability measures were excellent for all 3 parameters (0.94, 0.94, and 0.93, respectively). Point estimates for interobserver (0.84, 0.83, and 0.77, respectively) and test-retest (0.85, 0.82, and 0.76, respectively) reliability measures were good.

Conclusion

Strain imaging is feasible and reproducible. Future studies will have to investigate the clinical relevance of this novel imaging modality.

Clinical trial registration

www.Clinicaltrials.gov, identifier NCT03092557.

Characteristics of Cumulative Annual Radiation Exposure in Young Intensive Care Unit Survivors

OBJECTIVES

Patients admitted to the intensive care unit (ICU) are at high risk for hazardous medical radiation exposure. However, the cumulative annual radiation exposure in ICU survivors remains unknown.

METHODS

This was a single-center retrospective study of all critically ill adult patients admitted to the 64-bed adult medical ICU at a quaternary medical center. The study included patients aged 18 to 39 years admitted through the year 2013 (January 1, 2013-December 31, 2013) who survived their respective ICU admission.

RESULTS

A total of 353 patients were included in the study. The median cumulative effective dose (CED) for the calendar year was 9.14 mSv (interquartile range, 1.74-27 mSv). In 11.6% of the patients (n = 41), CED was more than 50 mSv, while 5.1% of the patients (n = 18) exceeded annual CED of 100 mSv. Overall, radiation exposure from ICU-related imaging studies was lower than those from other medical settings (mean difference, -9.2 ± 83.6; P < 0.05). However, there was no statistically significant difference in exposure (ICU versus non-ICU) when restricting the analysis to patients with a CED of greater than 50 and greater than 100 mSv. Eighty-seven percent of the original cohort was alive at the end of the year.

CONCLUSIONS

Young ICU survivors are at risk for high annual radiation exposure from both ICU and non-ICU sources. A subset is exposed to hazardous annual radiation exposure in excess of 100 mSv.

Digital tomography in the diagnosis of a posterior pneumothorax in the intensive care unit

Portable chest radiography is a valuable tool in the intensive care unit. However, the supine position causes superposition of anatomical structures resulting in less reliable detection of certain abnormalities. Recently, a portable digital tomosynthesis (pDTS) prototype with a modified motorized X-ray device was developed. We aimed to compare the diagnostic value of pDTS to standard bedside chest radiography in the diagnosis of a posterior pneumothorax. A modified motorized X-ray device was developed to perform 15 radiographic projections while translating the X-ray tube 25 cm (10 cm ramp up and 15 cm during X-ray exposure) with a total radiation dose of 0.54 mSv. This new technique of pDTS was performed in addition to standard bedside chest X-ray in a patient with a confirmed posterior hydropneumothorax. The images were compared with the standard bedside chest X-ray and computed tomography (CT) images by two experienced radiologists. The posterior hydropneumothorax previously identified with CT was visible on tomosynthesis images but not with standard bedside imaging. Combining the digital tomosynthesis technique with the portable X-ray machine could increase the diagnostic value of bedside chest radiography for the diagnosis of posterior pneumothoraces while avoiding intrahospital transport and limiting radiation exposure compared to CT.

Cumulative radiation dose incurred during the management of complex pleural space infection

BACKGROUND

Complex pleural space infections are commonly managed with antibiotics, pleural drainage, intrapleural fibrinolytic therapy, and surgery. These strategies often utilize radiographic imaging during management, however little data is available on cumulative radiation exposure received during inpatient management. We aimed to identify the type and quantity of radiographic studies along with the resultant radiation exposure during the management of complex pleural space infections.

METHODS

Retrospective review of community network healthcare system from January 2015 to July 2018. Patients were identified through billing databases as receiving intrapleural fibrinolytic therapy and/or surgical intervention. Patient demographics, clinical outcomes, and inpatient radiographic imaging was collected to calculate cumulative effective dose.

RESULTS

A total of 566 patients were identified with 7275 total radiographic studies performed and a median cumulative effective dose of 16.9 (IQR 9.9-26.3) mSv. Multivariable linear regression analysis revealed computed tomography use was associated with increased cumulative dose, whereas increased age was associated with lower cumulative dose. Over 74% of patients received more than 10 mSv, with 7.4% receiving more than 40 mSv.

CONCLUSIONS

The number of radiographic studies and overall cumulative effective dose in patients hospitalized for complex pleural space infection was high with the median cumulative effective dose > 5 times normal yearly exposure. Ionizing radiation and modern radiology techniques have revolutionized medical care, but are likely not without risk. Additional study is warranted to identify the frequency and imaging type needed during complex pleural space infection management, attempting to keep ionizing radiation exposure as low as reasonably possible.

Reducing chest radiography utilization in the medical intensive care unit

BACKGROUND AND PURPOSE

Daily chest radiographs (CXRs) have long been a routine part of care. However, evidence as well as changing technology has promoted on-demand CXRs as beneficial to patient care. We found that a substantial number of routine daily CXRs were being ordered, with some of the orders staying active even after extubation.

METHODS

Within a 19-bed adult medical ICU, we prospectively utilized 3 intervention phases from October 1, 2014, to February 28, 2018, to reduce routine CXRs. Nurse Practitioners (NP) initiated this quality improvement (QI) project, aiming to reduce the number of unnecessary of CXRs. Interventions included staff survey, routine CXR order removal, duplicate alerts, visual reminders, and an electronic clinical decision support tool. Monthly education of appropriate CXRs and bedside ultrasound were facilitated by NPs. The outcome measures of interest include: the number of CXRs per patient-day, the number of routine and on-demand CXRs, mortality rate, ICU length of stay, and ventilator days, radiation and cost.

CONCLUSIONS

Total number of CXRs per patient-day decreased by 36.1%. The proportion of routine CXRs decreased from 55.37% to 13.18%; on-demand orders increased, from 44.63% to 86.82%; and calculated radiation-exposure per census decreased, from 0.011 to 0.008 mSv. In addition, charges to patients for CXRs decreased by $7,750/month. ICU mortality and ventilator days per census remained stable.

IMPLICATIONS FOR PRACTICE

By an orchestrated process that included creating awareness and desire to change CXR ordering practices, we were able to decrease routine CXRs and increase on-demand utilization while maintaining counterbalance measures.

The use of national collaborative to promote advanced practice registered nurse-led high-value care initiatives

BACKGROUND

High-value healthcare focuses on improving healthcare to produce cost effective care, however limited information on the role of advanced practice registered nurses (APRNs) exists.

PURPOSE

This descriptive report describes APRN-led initiatives implemented as part of a national collaborative promoting the Choosing Wisely® campaign and high-value care measures.

METHOD

An APRN national collaborative focuses on developing and implementing high-value care initiatives. Monthly calls, podcasts, and a file sharing platform are used to facilitate the work of the national collaborative.

FINDINGS

A total of 16 APRN teams from 14 states are participating and have implemented a number of initiatives to reduce unnecessary testing and treatments, promote appropriate antibiotic use, and promote optimal clinical practices such as mobility for hospitalized elderly patients, among others.

DISCUSSION

A national collaborative has proven to be a successful way to engage APRN teams to focus on targeting high-value care and promoting evidence-based practices in clinical care.

Comparison of Efficacy of LUS and CXR in the Diagnosis of Children Presenting with Respiratory Distress to Emergency Department

Introduction

Respiratory distress (RD) in children is a life-threatening condition. Delay in diagnosis has a deleterious effect on morbidity and mortality. The bedside lung ultrasound in emergency (BLUE) is a fast method that aims to accelerate the diagnosis with minimal radiological exposure. We targeted to evaluate the efficacy of BLUE protocol to speed and increase the precision of recognizing the cause of RD compared with chest X-ray (CXR) in the emergency department.

Materials and methods

A cross-sectional study on 63 children with RD attended the emergency of a tertiary, university-affiliated, pediatric medical center between January 2017 and January 2018.

Results

Most cases were males 52.4%. We designed to estimate the value of BLUE as a diagnostic tool for RD and comparing it with CXR. Pneumonia with or without pleural effusion was the main etiology of RD detected by BLUE in 47.7% of studied children, pulmonary edema in 22.2%, bronchiolitis and asthma in 17.4%, and pneumothorax in 12.7%. Lung ultrasound (LUS) was superior to CXR in the diagnosis of RD cause, and most cases, 47.7% were diagnosed with pneumonia with a sensitivity of 93.5% and specificity 96.9%.

Conclusion

Bedside lung ultrasound in emergency is an effective tool for identifying the cause of RD which is more sensitive and specific compared with CXR.

How to cite this article

Hegazy LM, Rezk AR, Sakr HM, Ahmed AS. Comparison of Efficacy of LUS and CXR in the Diagnosis of Children Presenting with Respiratory Distress to Emergency Department. Indian J Crit Care Med 2020;24(6):459–464.

Looking for solutions: vision and a call-for-attention for radiation research scientists

Purpose: The concept of benefit-risk assessment has often been propagated for clinical professionals for deciding the radiological exam for the patient. A detailed look into how to use this concept leads to several unanswered questions. The purpose of this article is to bring forth questions which have remained unanswered for several decades. These questions pertain to our inability to provide needed information to physicians for making benefit-risk assessment for deciding a frequent imaging modality like the computed tomography (CT) such as non-applicability of risk estimates to an individual patient, the concept of cumulative risk at low doses, accounting for the time gap between series of CT scans, risk variation with age, gender and disease condition. In the absence of concrete information on these, it becomes essentially benefit assessment rather than benefit-risk. The article also provides a motivation to think that there are a large number of patients getting exposed every year to radiation doses over 100 mSv of effective dose and several tens of mGy of organ doses. This may provide a very large cohort for radiation effect studies. Further, a series of ideas are presented as a vision for future studies. Conclusions: The article emphasizes the need to create a research agenda to deal with day-to-day questions faced in medical practice and provides a call-for-attention. Further, it provides some challenging ideas as outside of the box thinking points that may provide research direction for future years.