The report is a product of the VA/HSR&D Evidence Synthesis Program.
Evidence Brief: Near Infrared Spectroscopy for Detecting Brain Hematoma
Falls are a common cause of orthopedic and head injuries among elderly populations, particularly those residing in nursing homes. Most patients with moderate-severe injuries after falls are transported to an emergency department (ED) or trauma center, but clinicians may struggle with management decisions for patients with mild injuries, particularly when the circumstances of the fall are unknown and patients cannot provide additional history or participate in the physical exam due to pre-existing dementia or other cognitive disorders. Mild head injury management guidelines commonly recommend head computed tomography (CT) for all patients ≥ 65 years old. However, most patients with mild head injuries who undergo head CT have normal findings, raising concern about the overuse of head CT and implications for patient safety due to radiation exposure.
Near infrared spectroscopy (NIRS) is an imaging technique used to identify intracranial hematomas by detecting asymmetry in light absorption over the right and left sides of the head without the use of radiation. Handheld NIRS devices offer a portable, non-invasive, and quick means of evaluating patients with mild head injury for the presence of a brain hematoma – and could potentially aid in clinical decision-making to avoid unnecessary CTs.
This evidence brief sought to evaluate the potential impact of NIRS use among nursing home patients after falls by describing the technical feasibility of NIRS for detecting brain hematomas and synthesizing the evidence on the performance characteristics of NIRS, as well as its impact on diagnostic and therapeutic decision-making, patient outcomes, potential harms, and cost-effectiveness. Investigators with VA's Evidence-based Synthesis Coordinating Center in Portland, OR reviewed the literature including: MEDLINE®, Cochrane Database of Systematic reviews, Cochrane Central Register of Controlled Trials, PsycINFO, Health Technology Assessment, Database of Abstracts of Reviews of Effects, NHS Economic Evaluation Database, CINAHL, Military & Government Collection, and Scopus up to 6/30/2017. After reviewing 797 articles, 13 (12 observational studies and 1 systematic review) were used for this evidence brief.
Summary of Review
No studies were found that evaluated the use of NIRS among nursing home patients after falls. Instead, studies of NIRS have almost exclusively focused on demonstrating the technical feasibility of the device and its performance characteristics in series of patients who were referred for CT scans, providing little insight on how the use of NIRS impacts clinical decision-making, patient outcomes, and healthcare use. Moreover, studies of NIRS have mostly been in patients ≤ 60 years old, in the ED or hospital setting, with largely unreported disease severity and baseline risk factors for intracranial hemorrhage, thereby limiting the applicability of findings to older patients in nursing homes. In addition, no studies reported on the cost-effectiveness of NIRS.
Potential harms of NIRS as a test for hematomas in nursing home patients after falls are primarily related to the possibility of obtaining a negative NIRS scan in a patient who truly has a hematoma in need of further intervention. In addition, there could be unintended consequences of transporting fewer patients to EDs after falls, including strain on nursing home staff due to more frequent monitoring of patients as well as missed opportunities to identify reasons for patient falls if they do not undergo more extensive testing.
Given concerns about the overuse of CT and the potential benefits of NIRS as a diagnostic tool in nursing home patients with mild injuries after falls, it would be reasonable to consider implementation of a NIRS protocol in a pilot study among VA Community Living Centers. A pilot study could provide reliable estimates of CTs and ED transfers averted. However, because positive CT scans are rare in this situation, a much larger study (or decision modeling) would be needed to assess the frequency and clinical consequences of false negative NIRS scans. VA Pittsburgh's experience using Infrascanner© 2000 (commercially available NIRS handheld device) could provide guidance for other facilities to develop clinical policies regarding NIRS.
To avoid some of the methodologic limitations of existing studies of NIRS, future studies should:
- Report patients' baseline characteristics such as age, risk factors for intracranial hemorrhage, including use of anticoagulants, and degree of injury after falls including GCS (Glasgow Coma Scale) scores;
- Ensure blinding of radiologists reading CTs to NIRS results; and
- Include only completed NIRS scans in results, thereby limiting the potential for over-reporting of false negatives.
The Office of Community Engagement's Center for Compassionate Innovation (CCI) requested this evidence brief on the use of NIRS to evaluate patients in nursing homes, including VA Community Living Centers, for the presence of brain hematomas after falls. Findings will be used to inform subject matter experts' consideration of NIRS' clinical use and research, as well as program prioritization in the nursing home setting.
View the full report:
Mackey K, Peterson K, Bourne D, Anderson J, Boundy E, and Helfand M. Evidence Brief: Near Infrared Spectroscopy for Detecting Brain Hematoma. VA ESP Project #09-199; 2017.
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