Physician-staffed ambulance and increased in-hospital mortality of hypotensive trauma patients following prolonged prehospital stay: A nationwide study

Abstract

BACKGROUND:The benefits of physician-staffed emergency medical services (EMS) for trauma patients remain unclear because of the conflicting results on survival. Some studies suggested potential delays in definitive hemostasis due to prolonged prehospital stay when physicians are dispatched to the scene. We examined hypotensive trauma patients who were transported by ambulance, with the hypothesis that physician-staffed ambulances would be associated with increased in-hospital mortality, compared with EMS personnel-staffed ambulances. METHODS:A retrospective cohort study that included hypotensive trauma patients (systolic blood pressure ≤ 90 mm Hg at the scene) transported by ambulance was conducted using the Japan Trauma Data Bank (2004Bank ( -2019. Physician-staffed ambulances are capable of resuscitative procedures, such as thoracotomy and surgical airway management, while EMS personnel-staffed ambulances could only provide advanced life support. In-hospital mortality and prehospital time until the hospital arrival were compared between patients who were classified based on the type of ambulance. Inverse probability weighting was conducted to adjust baseline characteristics including age, sex, comorbidities, mechanism of injury, vital signs at the scene, injury severity, and ambulance dispatch time. RESULTS:Among 14,652 patients eligible for the study, 738 were transported by a physician-staffed ambulance. In-hospital mortality was higher in the physician-staffed ambulance than in the EMS personnel-staffed ambulance (201/699 [28.8%] vs. 2287/13,090 [17.5%]; odds ratio, 1.90 [1.61-2.26]; adjusted odds ratio, 1.22 [1.14-1.30]; p < 0.01), and the physician-staffed ambulance showed longer prehospital time (50 [36-66] vs. 37 [29-48] min, difference = 12 [11-12] min, p < 0.01). Such potential harm of the physician-staffed ambulance was only observed among patients who arrived at the hospital with persistent hypotension (systolic blood pressure < 90 mm Hg on hospital arrival) in subgroup analyses. CONCLUSION:Physician-staffed ambulances were associated with prolonged prehospital stay and increased in-hospital mortality among hypotensive trauma patients compared with EMS personnel-staffed ambulance.

Impact of emergency physician-staffed ambulances on preoperative time course and survival among injured patients requiring emergency surgery or transarterial embolization: A retrospective cohort study at a community emergency department in Japan

“…Firstly, this study captured in-depth information such as presentation time, presentation day, and type of definitive intervention. Indeed, these variables were important confounders not measured in previous studies [ 13 – 24 ]. Additionally, this study clarified the difference in hospital LOS and discharge disposition between EP-staffed ambulances and ELST-staffed ambulances.…”

“…Most previous investigations comparing the outcomes of injured patients transported by EP-staffed and ELST-staffed ambulances used large trauma databases, but a considerable amount of data was missing in those studies [ 15 , 17 , 20 , 24 ]. To handle missing data, previous investigations have eliminated all missing data [ 15 , 20 , 24 ] or used multiple imputation [ 17 ], but both methods can generate bias. Furthermore, to mitigate the risk of biased assessment, the author who constructed the database (K.S.)…”

“…Therefore, most Japanese tertiary medical centers, including the study site, run a hospital-based emergency physician (EP) delivery system for early initiation of advanced trauma care [12]. Nevertheless, the effect of EP deployment to the prehospital scene on outcomes among injured patients remains controversial: Several studies have shown that EP involvement in prehospital trauma care is associated with improved survival in patients with trauma [13][14][15][16][17][18][19] whereas other studies report no significant differences [20][21][22][23] or decreased survival [24]. Although injured patients requiring definitive intervention, such as surgery or TAE, are an extremely time-sensitive population, previous studies have not focused on this important trauma subset [13][14][15][16][17][18][19][20][21][22][23][24], and little is known regarding whether and how an EP delivery system affects the preoperative time course and patient survival.…”

“…Nevertheless, the effect of EP deployment to the prehospital scene on outcomes among injured patients remains controversial: Several studies have shown that EP involvement in prehospital trauma care is associated with improved survival in patients with trauma [13][14][15][16][17][18][19] whereas other studies report no significant differences [20][21][22][23] or decreased survival [24]. Although injured patients requiring definitive intervention, such as surgery or TAE, are an extremely time-sensitive population, previous studies have not focused on this important trauma subset [13][14][15][16][17][18][19][20][21][22][23][24], and little is known regarding whether and how an EP delivery system affects the preoperative time course and patient survival. Additionally, despite hospital LOS being a sensitive indicator that reflects patients' disease burden, previous studies have not clarified how EP involvement in prehospital trauma care affects this important parameter, as compared with ELSTs [13][14][15][16][17][18][19][20][21][22][23][24].…”

“…Although injured patients requiring definitive intervention, such as surgery or TAE, are an extremely time-sensitive population, previous studies have not focused on this important trauma subset [13][14][15][16][17][18][19][20][21][22][23][24], and little is known regarding whether and how an EP delivery system affects the preoperative time course and patient survival. Additionally, despite hospital LOS being a sensitive indicator that reflects patients' disease burden, previous studies have not clarified how EP involvement in prehospital trauma care affects this important parameter, as compared with ELSTs [13][14][15][16][17][18][19][20][21][22][23][24]. Because running an EP-staffed ambulance requires considerable cost as well as human resources [12,20], rigorous investigation of its effectiveness compared with that of a conventional ELST-staffed ambulance is warranted.…”