Changing the paradigm for diagnostic MRI in pediatrics: Don't hold your breath

Assessing and conveying risks and benefits of imaging in neonates using ionizing radiation and sedation/anesthesia

Neonates represent a unique subset of the pediatric population that requires special attention and careful thought when implementing advanced cross-sectional imaging with CT or MRI. The ionizing radiation associated with CT and the sedation/anesthesia occasionally required for MRI present risks that must be balanced against the perceived benefit of the imaging examination in the unique and particularly susceptible neonatal population. We review the perceived risks of ionizing radiation and the more concrete risks of sedation/anesthesia in term and preterm neonates in the context of an imaging paradigm. When the expected diagnostic yield from CT and MRI is similar, and sedation is required for MRI but not for CT, CT likely has the higher benefit-to-risk ratio in the neonate. However, despite the risks, the most appropriate imaging modality should always be chosen after thoughtful consideration is given to each unique patient and informed discussions including radiology, anesthesia, neonatology and the parents/caregivers are pursued.

Cost-effectiveness analysis of sedation and general anesthesia regimens for children undergoing magnetic resonance imaging in Japan

PURPOSE

The anesthesiologist-directed sedation service has not been well established in Japan partly due to reimbursement issue. In this study, we compared the cost-effectiveness of sedation by non-anesthesiologists with that of sedation or general anesthesia by anesthesiologists under the Japanese medical fee schedule.

METHODS

We conducted a single-center observational study with patients who required sedation or general anesthesia for magnetic resonance imaging (MRI) during a 12-month period. Costs per patient and failure rates of imaging were modeled in a decision analysis tree with sensitivity analysis. Costs were estimated from the health-care sector perspective.

RESULTS

A total of 1546 patients were analyzed. The failure rate of sedation by non-anesthesiologists was 17.5% (264 out of 1506), whereas all the sedation and general anesthesia by anesthesiologists were successful. The cost-effectiveness analysis with setting successful sedation as outcomes showed that the mean cost per patient was 84.2 USD for sedation by anesthesiologists, followed by 74.2-92.7 USD for intravenous sedation by non-anesthesiologists, 112.1-458.3 USD for oral or rectal sedation by non-anesthesiologists, and 605.4 USD for general anesthesia by anesthesiologists. The one-way sensitivity analysis demonstrated that the cost per patient of sedation by a non-anesthesiologist would remain higher than that of sedation by an anesthesiologist, provided that the failure rate is over 11.3% for sedation via oral or rectal route, or over 3.6% for intravenous route, respectively.

CONCLUSIONS

Anesthesia-directed sedation would be more cost-effective than oral or rectal sedation by non-anesthesiologists for children undergoing MRI in the Japanese medical fee schedule.

Should I irradiate with computed tomography or sedate for magnetic resonance imaging?

In the context of pediatric cross-sectional imaging, the risk of ionizing radiation for CT and the potential adverse effects associated with sedation/anesthesia for MRI continue to provoke lively discussions in the pediatric literature and lay press. This is particularly true for issues relating to the risks of ionizing radiation for CT, which has been a topic of discussion for nearly two decades. In addition to understanding these potential risks and the importance of minimizing individual pediatric patient exposure to ionizing radiation, it is equally important for radiologists to be able to frame these risks with respect to the potential for adverse outcomes associated with the use of anesthesia for cross-sectional imaging in the pediatric population. Notably, before such risks can be estimated and compared, one should always consider the potential utility of each imaging modality for a given diagnosis. If one cross-sectional imaging modality is likely to be far superior to the other for a specific clinical question, every effort must be made to safely image the child, even if sedation/anesthesia is required.

Incidence and Causes of Adverse Events in Diagnostic Radiological Studies Requiring Anesthesia in the Wake-Up Safe Registry

OBJECTIVES

General anesthesia or sedation can facilitate the completion of diagnostic radiological studies in children. We evaluated the incidence, predictors, and causes of adverse events (AEs) when general anesthesia is provided for diagnostic radiological imaging.

METHODS

Deidentified data from 24 pediatric tertiary care hospitals participating in the Wake-Up Safe registry during 2010-2015 were obtained for analysis. Children 18 years or younger receiving general anesthesia for radiological procedures were identified using Current Procedural Terminology codes, and reported AEs were analyzed if they were associated with anesthetic care at magnetic resonance imaging or computed tomography locations. Logistic regression was used to determine predictors of AE occurrence in cases with complete covariate data.

RESULTS

We identified 175,486 anesthetics for diagnostic radiological exams, compared with 83 AEs in magnetic resonance imaging or computed tomography locations (AE incidence of 0.05%). In multivariable analysis, AEs were more likely among patients with American Society of Anesthesiologists physical status IV compared with American Society of Anesthesiologists physical status I patients (adjusted odds ratio, 8.9; 95% confidence interval, 2.8-28.0; P < 0.001). Twenty-three AEs resulted in harm to the patient, whereas 32 AEs required unplanned hospital or intensive care unit admission. Anesthetic complications or issues were the most common cause of AEs (n = 52).

CONCLUSIONS

Anesthesia provided for pediatric radiological studies is very safe and with an overall low AE incidence. The contribution of anesthetic complications to reported AEs suggests opportunities for further process improvement in this setting.

Free-breathing abdominal T1 mapping using an optimized MR fingerprinting sequence

In this work, we propose a free-breathing magnetic resonance fingerprinting (MRF) method that can be used to obtain B₁⁺ -robust quantitative T₁ maps of the abdomen in a clinically acceptable time. A three-dimensional MRF sequence with a radial stack-of-stars trajectory was implemented, and its k-space acquisition ordering was adjusted to improve motion-robustness in the context of MRF. The flip angle pattern was optimized using the Cramér-Rao Lower Bound, and the encoding efficiency of sequences with 300, 600, 900 and 1800 flip angles was evaluated. To validate the sequence, a movable multicompartment phantom was developed. Reference multiparametric maps were acquired under stationary conditions using a previously validated MRF method. Periodic motion of the phantom was used to investigate the motion-robustness of the proposed sequence. The best performing sequence length (600 flip angles) was used to image the abdomen during a free-breathing volunteer scan. When using a series of 600 or more flip angles, the estimated T₁ values in the stationary phantom showed good agreement with the reference scan. Phantom experiments revealed that motion-related artifacts can appear in the quantitative maps and confirmed that a motion-robust k-space ordering is essential. The in vivo scan demonstrated that the proposed sequence can produce clean parameter maps while the subject breathes freely. Using this sequence, it is possible to generate B₁⁺ -robust quantitative maps of T₁ and B₁⁺ next to M₀ -weighted images under free-breathing conditions at a clinically usable resolution within 5 min.

Pediatric Anesthesia Outside the Operating Room: Safety and Systems

Anesthesia care performed outside the operating room is a growing area of pediatric anesthesia practice. The anesthesiology team expects to care for children in diverse locations, which include diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology sites, and the cardiac catheterization laboratory. To provide safe, high-quality care the anesthesiologist working in these environments must understand the unique environmental, logistical, and perioperative considerations and risks involved with each remote location. This 2-part review provides an overview of safety and system considerations in pediatric nonoperating room anesthesia before describing in more detail considerations for particular remote anesthetizing locations.

Pediatric Anesthesia Outside the Operating Room: Case Management

Anesthesiology teams care for children in diverse locations, including diagnostic and interventional radiology, gastroenterology and pulmonary endoscopy suites, radiation oncology units, and cardiac catheterization laboratories. To provide safe, high-quality care, anesthesiologists working in these environments must understand the unique environmental and perioperative considerations and risks involved with each remote location and patient population. Once these variables are addressed, anesthesia and procedural teams can coordinate to ensure that patients and families receive the same high-quality care that they have come to expect in the operating room. This article also describes some of the considerations for anesthetic care in outfield locations.

Trends in Outpatient Procedural Sedation: 2007-2018

BACKGROUND

Pediatric subspecialists routinely provide procedural sedation outside the operating room. No large study has reported trends in outpatient pediatric procedural sedation. Our purpose in this study was to identify significant trends in outpatient procedural sedation using the Pediatric Sedation Research Consortium.

METHODS

Prospectively collected data from 2007 to 2018 were used for trending procedural sedation. Patient characteristics, medications, type of providers, serious adverse events, and interventions were reported. The Cochran-Armitage test for trend was used to explore the association between the year and a given characteristic.

RESULTS

A total of 432 842 sedation encounters were identified and divided into 3 4-year epochs (2007-2011, 2011-2014, and 2014-2018). There was a significant decrease in infants <3 months of age receiving procedural sedation (odds ratio = 0.97; 95% confidence interval, 0.96-0.98). A large increase was noticed in pediatric hospitalists providing procedural sedation (0.6%-9.5%; P < .001); there was a decreasing trend in sedation by other providers who were not in emergency medicine, critical care, or anesthesiology (13.9%-3.9%; P < .001). There was an increasing trend in the use of dexmedetomidine (6.3%-9.3%; P < .001) and a decreasing trend in the use of chloral hydrate (6.3%-0.01%; P < .001) and pentobarbital (7.3%-0.5%; P < .001). Serious adverse events showed a nonsignificant increase overall (1.35%-1.75%).

CONCLUSIONS

We report an increase in pediatric hospitalists providing sedation and a significant decrease in the use of chloral hydrate and pentobarbital by providers. Further studies are required to see if sedation services decrease costs and optimize resource use.

The Migration of Caudally Threaded Thoracic Epidural Catheters in Neonates and Infants

BACKGROUND

The migration of pediatric thoracic epidural catheters via a thoracic insertion site has been described. We assessed the migration of caudally threaded thoracic epidural catheters in neonates and infants at our institution.

METHODS

The anesthesia records and diagnostic imaging studies of neonates and infants who had caudal epidural catheters placed during a 26-month period at our hospital were analyzed. Imaging studies were reviewed for changes in epidural catheter tip position.

RESULTS

Eighty-five patients 1-325 days of age (median, 51 days; interquartile range, 39-78 days) and weights of 2.5-9.5 kg (median, 5 kg; interquartile range, 4.3-5.8 kg) met the study criteria. Fifty-four (64%) of the patients (95% CI, 52%-73%) experienced catheter migration of 1 or more vertebral levels (range, 3 levels caudad [outward] to 3 levels cephalad [inward]), and 23 (27%) of the patients (95% CI, 18%-38%) experienced catheter migration to the T4 level or higher. Migration of 2 or more vertebral levels occurred only in children who weighed <6 kg and were under 73 days of age.

CONCLUSIONS

Epidural catheter migration occurs commonly in neonates and infants. Postoperative imaging is crucial to confirm catheter tip location after epidural catheter placement, as failure to assess catheter migration might result in suboptimal analgesia or other undesirable outcomes.

Radiologic Imaging in Trauma Patients with Cervical Spine Immobilization at a Pediatric Trauma Center

BACKGROUND

Pediatric trauma patients with cervical spine (CS) immobilization using a cervical collar often require procedural sedation (PS) for radiologic imaging. The limited ability to perform airway maneuvers while CS immobilized with a cervical collar is a concern for emergency department (ED) staff providing PS.

OBJECTIVE

To describe the use of PS and analgesia for radiologic imaging acquisition in pediatric trauma patients with CS immobilization.

METHODS

Retrospective medical record review of all trauma patients with CS immobilization at a high-volume pediatric trauma center was performed. Patient demographics, imaging modality, PS success, sedative and analgesia medications, and adverse events were analyzed. Patients intubated prior to arrival to the ED were excluded.

RESULTS

A total of 1417 patients with 1898 imaging encounters met our inclusion criteria. A total of 398 patients required more than one radiographic imaging procedure. The median age was 8 years (range 3.8-12.75 years). Computed tomography of the head was used in 974 of the 1898 patients (51.3%). A total of 956 of the 1898 patients (50.4%) required sedatives or analgesics for their radiographic imaging, with 875 (91.5%) requiring a single sedative or analgesic agent, and 81 (8.5%) requiring more than one medication. Airway obstruction was the most common adverse event, occurring in 5 of 956 patients (0.3%). All imaging procedures were successfully completed.

CONCLUSION

Only 50% of CS immobilized, nonintubated patients required a single sedative or analgesic medication for their radiologic imaging. Procedural success was high, with few adverse events.

Is MRI imaging in pediatric age totally safe? A critical reprisal

Current radiological literature is strongly focussed on radiation imaging risks. Indeed, given there is a small but actual augment in cancer risk from exposure to ionizing radiation in children, it is important to understand what the risk of alternative techniques could be. We retrospectively review literature data concerning possible MR imaging risks, focussing on the biological effects of MR, sedation and gadolinium compound risks when dealing with infant patients. The main concerns can be summarized in: (1) Biological effects of non-ionizing electromagnetic fields (EMF) employed-whose mechanisms of interaction with human tissues are polarization, induced current, and thermal heating, respectively. (2) Risks associated with noises produced during MRI examinations. (3) Hazards from ferromagnetic external and/or implanted devices-whose risk of being unintentionally brought inside MR room is higher in children than in adults. (4) Risks associated with sedation or general anaesthesia, essential problem in performing MR in very young patients, due to the exam long-lasting. (5) Risks related to gadolinium-based contrast agents, especially considering the newly reported brain deposition.

Noteworthy Literature published in 2017 for Congenital Cardiac Anesthesiologists

This review focuses on the literature published during the 13 months from December 2016 to December 2017 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Five themes are addressed during this time period and 100 peer-reviewed articles are discussed.