-Original-

Effects of a Physician-Staffed Helicopter Emergency Medical Service on Cerebral Infarction Outcomes: A Registry-Based Observational Study

Kazuki Mashiko¹, Kazuhiro Okada¹, Yoshiaki Hara¹, Hayato Takayama², Yoshihide Nakagawa³, Makoto Kobayashi⁴, Asuka Tsuchiya³, Tatsuya Hayakawa⁵, Tatsuya Noda⁶, Kayo Ito⁷, Hiroshi Endo⁸, Takayuki Suda⁹, Youichi Yanagawa¹⁰, Seiya Kato¹¹, Yuji Yamamori¹², Katsuhiro Kanemaru¹³, Terutake Yonemori¹⁴ and Shoji Yokobori¹⁵

¹Nippon Medical School Chiba Hokusoh Hospital, Shock and Trauma Center, Chiba, Japan
²National Hospital Organization Nagasaki Medical Center, Nagasaki, Japan
³Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Kanagawa, Japan
⁴Tottori Emergency and Critical Care Medical Center, Tottori Prefectural Central Hospital, Tottori, Japan
⁵Advanced Emergency and Critical Care Center, Seirei Mikatahara General Hospital, Shizuoka, Japan
⁶Department of Public Health, Health Management and Policy, Nara Medical University, Nara, Japan
⁷Minister's Secretariat, Ministry of Environment Government of Japan, Tokyo, Japan
⁸Advanced Emergency and Critical Care Center, Niigata University Medical and Dental Hospital, Niigata, Japan
⁹Emergency and Critical Care Center, Mito Saiseikai General Hospital, Ibaraki, Japan
¹⁰Department of Acute Critical Care Medicine, Juntendo University Shizuoka Hospital, Shizuoka, Japan
¹¹Arida Municipal Hospital, Wakayama, Japan
¹²Advanced Emergency and Critical Care Center, Shimane Prefectural Central Hospital, Shimane, Japan
¹³Emergency and Critical Care Center, Miyazaki Prefectural Nobeoka Hospital, Miyazaki, Japan
¹⁴Department of Emergency and Critical Care Medicine, Urasoe General Hospital, Okinawa, Japan
¹⁵Nippon Medical School, Emergency and Critical Care Medicine, Tokyo, Japan

Background: The effects of helicopter emergency medical services on the treatment of cerebral infarction remains unclear. We investigated the effects of helicopter transport on outcomes in patients with cerebral infarction.
Methods: This study included 1,246 patients with cerebral infarction who were assigned to two groups: patients transported by "Doctor-Heli" (DH group) and patients transported by ground ambulances (GA group). Cerebral performance category (CPC), overall performance category (OPC), and in-hospital mortality were evaluated. Multivariate logistic regression analysis was used to adjust for background factors and evaluate a subgroup of patients with severe cerebral infarction (i.e., a National Institutes of Health Stroke Scale (NIHSS) score >10).
Results: The DH group included more patients with severe cerebral infarction. No difference was observed in the interval from illness onset to recombinant tissue plasminogen activator treatment between the groups; however, the interval from illness onset to interventional radiology (IR) was significantly shorter in the DH group. The DH group had a lower CPC than the GA group, but there was no significant difference in OPC. Multivariate logistic regression analysis showed that the odds ratio of DH transport for OPC1-2 was 2.33. Subgroup analysis of severe cases yielded odds ratios of 2.19 and 2.62 for CPC1-2 and OPC1-2 respectively.
Conclusion: The DH group included patients with severe cerebral infarction living in remote areas and provided with emergency IR treatment. This analysis suggested that DH transport improves OPC and CPC, particularly in patients with an NIHSS scores of >10.

J Nippon Med Sch 2025; 92: 391-398

Keywords
helicopter emergency medical service, stroke, cerebral infarction

Correspondence to
Kazuki Mashiko, MD, Nippon Medical School Chiba Hokusoh Hospital, Shock and Trauma Center, 1715 Kamagari, Inzai, Chiba 270-1694, Japan
kmashiko@nms.ac.jp

Received, October 2, 2024
Accepted, July 23, 2025