Current Status of Neurocritical Care for Traumatic Brain Injury in Japan

Editor’s Note: Author Dr. Eiichi Suehiro works in the department of neurosurgery at the International University of Health and Welfare School of Medicine in Narita, Japan.

First of all, I would like to express my deepest sympathy to those who died from Corona virus disease 2019 (COVID-19) and to all patients who are fighting the disease. I also pay tribute to all those in the medical profession who respond.

Is Neurotrauma/Neurocritical Care a Minor Area in Japan?

One of the characteristics of Japanese neurosurgeons is that they are all-rounders. In other words, Japanese neurosurgeons not only perform surgery, but are also responsible for initial medical treatment, internal medical treatment, postoperative management and rehabilitation management. In this situation, the position of neurotrauma/neurocritical care in Japan is unclear. The Japan Neurosurgical Society had 10,014 members in September 2019, but the Japan Society of Neurotraumatology had only 917 members (9.2%). In 2015, a survey of neurosurgical specialists asking about their subspecialty produced multiple answers, with only 16.7% selecting neurotrauma, whereas cerebrovascular disorders was selected by 61.4%¹. In a similar questionnaire conducted in 2006, neurotrauma was selected by 35.1%, so in 2015 this category fell to less than half¹. Furthermore, only 3.8% chose neurocritical care in the 2015 survey¹, and among senior residents in neurosurgery, only 11.7% chose neurotrauma as a future subspecialty in which they would like to engage². Therefore, there may be a further decline in the number of neurosurgeons specializing in neurotrauma. These findings show that Japanese neurosurgeons are all-rounders and have subspecialty dispersion, and that neurotrauma/neurocritical care is currently a minor subspeciality compared to cerebrovascular disorders and brain tumors.

Role Sharing and Practice of Traumatic Brain Injury Treatment in Japan

The circumstances described above raise the questions of how and by whom care for traumatic brain injury (TBI) and neurocritical care are provided in Japan. We conducted a questionnaire survey of TBI treatment at training facilities for neurosurgery specialists in 2008. First, we found that 29% of institutions offered treatment only in emergency departments, 34% performed neurosurgery only and 36% were involved jointly in initial medical care for TBI³. Many neurosurgeons seemed to work in the initial medical care. Postoperative management was performed at rates of 11% for emergency departments, 76% for neurosurgery, 3% for intensive care departments and 9% jointly³. Thus, neurosurgery departments were frequently responsible for postoperative management, and it is clear that neurosurgeons in Japan are heavily involved from initial medical care to discharge of a patient with TBI. Next, we examined the fields related to neurocritical care and found that 55% of institutions measured intracranial pressure (ICP) and 21% monitored brain oxygenation in cases with severe TBI³. In Japan, measurement of brain tissue oxygen tension has yet to be approved, and the only permitted measurement is jugular bulb oxygen saturation. The survey showed that 76% of facilities used active temperature control³, which appeared to be higher than the rate of other neurocritical care items. It is evident from these figures that neurocritical care is not widespread in Japan. When asked about the reasons for this situation in the questionnaire, 30% of the facilities stated that there was no evidence for the efficacy of neurocritical care³, and 60-70% cited a lack of medical staff or hospital funding³. Therefore, neurocritical care in Japan is not widespread because neurosurgeons are busy with surgery and are unable to devote time to neurocritical care. The role of this treatment in Japan requires further discussion, as has occurred in the United States.

Current Status of Neurocritical Care in Japan

A glimpse of the current state of neurocritical care in Japan can be obtained from the Japan Neurotrauma Data Bank, which is managed by the Japan Society of Neurotraumatology. An observational study in patients with severe TBI has been conducted intermittently over two-year periods. Four projects, P1998, P2004, P2009 and P2015, have been conducted to date, with the rate of use of an ICP sensor used as an index for use of neurocritical care. The rates were 29.9% in P1998, 28.8% in P2004, 28.0% in P2009 and 36.7% in P2015 (Figure 1). These are very low rates compared to those in the United States. In Japan, guidelines for treatment and management of severe TBI were published in 2001. These guidelines recommend use of ICP sensors for severe TBI, but this did not contribute to widespread use of these sensors. However, over time, we have slowly proven the utility of ICP sensors⁴, and although still inadequate, an effect of this effort may have begun to emerge in the P2015 study. Another index of neurocritical care, the rate of sedation in severe TBI management, was 15.1% in P2004, 41.2% in P2009 and 50.6% in P2015 (Figure 2). Sedation is a fundamental item in the algorithm for treatment of patients with increased ICP. These changes in rates may reflect the frequency of use of this algorithm; that is, they suggest that the frequency of use of neurocritical care is increasing in treatment of patients with increased ICP in Japan. However, the favorable outcome rates at discharge were 32.9%, 29.8% and 30.3%, and the mortality rates were 37.7%, 41.5% and 35.8% in P2004, P2009 and P2015, respectively. These data suggest that an overall positive effect of neurocritical care has yet to be seen.

Efforts to Spread Neurocritical Care by Academic Societies

Japanese neurotraumatologists are increasingly recognizing the importance of neurocritical care and are working to spread use of neurocritical care. Guidelines for treatment and management of severe TBI in Japan were first published in 2001, and the fourth edition was published in October 2019. Intensive care unit (ICU) management is described in detail based on 15 items (Table 1) in these guidelines. Published studies that provided evidence for the guidelines are given as “references”, and the actual situation in Japan is given in “comments”. The contents of the guidelines support general neurosurgeons, and these contents have been devised to allow use in actual clinical practice. In addition, we are working on construction of a system for specialists certified by the Japan Society of Neurotraumatology to increase the motivation of young neurosurgeons to engage in neurotrauma/neurocritical care treatment. This approach has already had an effect based on an increase in the number of new members of the Japan Society of Neurotraumatology. The Japanese Society of Intensive Care Medicine has also begun to work on neurocritical care. In Japan, the neurotrauma and stroke fields do not have many intensivists, and this may have led to a lack of communication between neurosurgeons and intensivists. In recent years, the Japanese Society of Intensive Care Medicine has held a neurocritical care seminar about three times a year to educate members on neurocritical care. Currently, only intensivists attend this seminar, but greater attendance by neurosurgeons is likely to resolve the possible communication problem described above. In the future, it is expected that positions in the field of neurocritical care will be established and become more widespread in Japan. This will lead to neurosurgeons and intensivists working together to deliver more advanced neurocritical care that will improve outcomes in patients with TBI.

Table 1. Fifteen items related to ICU management that are described in detail in the guidelines for treatment and management of traumatic brain injury in Japan.

References

1. Suzuki, M., Suehiro, E. (2017). Questionnaire Survey for Board Certified Neurosurgeons. Jpn J Neurosurg (Tokyo), 26 (11), 817-828.

2. Suehiro, E., Kohmura, E., Suzuki, M. (2017). Survey of the Current Status of Resident Physician by the Japan Neurosurgical Society. Jpn J Neurosurg (Tokyo), 26 (12), 899-909.

3. Suehiro, E., Fujisawa, H., Koizumi, H., Yoneda, H., Ishihara, H., Nomura, S., Kajiwara, K., Fujii, M., Suzuki, M. (2011). Survey of Current Neurotrauma Treatment Practice in Japan. World Neurosurg, 75 (3/4), 563-568.

4. Suehiro, E., Fujiyama, Y., Koizumi, H., Suzuki, M. and the Japan Neurotrauma Data Bank Committee. (2017). Directions for use of intracranial pressure monitoring in the treatment of severe traumatic brain injury using data from the Japan Neurotrauma Data Bank. J Neurotrauma 34, 2230-2234.