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Dissociative anesthesia in a prehospital environment


Dissociative anesthesia is usually performed in a hospital setting. The advantages of ketamine are respiratory and hemodynamic stability, low price and worldwide availability. Its use in the emergency room is safe, but use in a prehospital environment is less known and less reported.


To analyze the safety and complications of dissociative anesthesia guided by an institutional protocol in a prehospital environment.


A retrospective, observational series, protocol-driven study with dissociative anesthesia with ketamine plus midazolan from 1998 to 2004 (excluding 2000, because no available data). All patients were attended by an urban advanced life support unit.


Ninety-seven patients received dissociative anesthesia in the period. In nine patients ketamine was administered for rapid sequence intubation, and these were excluded. Eighty-eight met the criteria for sedation and analgesia. Collision was the leading trauma kinematics in 50%. The main indication for dissociative anesthesia was vehicle-entrapped patients in 26.5%. The most important traumatic lesion was inferior extremity fractures in 49.25%. The complications reported in this series were four orotracheal intubations secondary to: seizure (one patient), lowered level of consciousness (two patients), and protection of the airway from orofacial hemorrhage after reduction of a mandibular fracture and dislocation (one patient). One respiratory depression was treated by bag–valve–mask-assisted ventilatory support. Neither cardiorespiratory arrest nor deaths occurred. The mean administered doses were 118.5 mg for ketamine and 4.84 mg for midazolan. The percentages of orotracheal intubations were greater in group 1 of 19 patients with Glasgow Coma Scale (GCS) less than or equal to 13 corresponding to 10.52%, versus 2.89% in group 2 of 69 patients with GCS of 14 and 15. Table 1 presents the data variable comparison between groups 1 and 2.

Table 1 Variable comparison between groups 1 and 2


Dissociative anesthesia is a safe procedure even in a prehospital environment when performed in a group of patients with GCS 14 or 15 after implementation of an institutional protocol. Proficiency in definitive airway techniques is necessary. Improvement in the quality of attendance and humanization of the EMS are best performed by introducing analgesia protocols into the prehospital environment.

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Belezia, B., Moura, A., Antunes, A. et al. Dissociative anesthesia in a prehospital environment. Crit Care 11, P109 (2007).

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  • Ketamine
  • Glasgow Coma Scale
  • Institutional Protocol
  • Advanced Life Support
  • Orotracheal Intubation