title: The association between ketamine given for prehospital chemical restraint with intubation and hospital admission.
abstract: BACKGROUND
  Intramuscular ketamine has become increasingly popular for prehospital chemical restraint of severely agitated or violent patients because of its favorable adverse effect profile, rapid onset, and wide therapeutic window. However, there is currently no literature quantifying the need for intubation or hospital admission for these patients once they reach the emergency department.
  
  
  METHODS
  Medical records for patients receiving prehospital ketamine who were transported to a single level 1 trauma center were abstracted. Ketamine dose, patient weight, final disposition, and presence of intubation were recorded. Exclusion criteria were missing dose or weight and ketamine given for an indication other than chemical restraint. Statistical analysis was preformed with unadjusted Student t test. Statistical significance was defined as P < .05.
  
  
  RESULTS
  A convenience sample of 51 consecutive patients was identified with 2 excluded because of missing data, leaving 49 for analysis. Ketamine dosing ranged from 2.25 to 9.42 mg/kg (mean, 5.26 ± 1.65 mg/kg). Significant differences were noted between those who required intubation (n = 14) and those who did not (n = 35) (6.16 ± 1.62 mg/kg vs 4.90 ± 1.54 mg/kg, P = .02). No patients were intubated prehospital. There was an increased dose in patients admitted to a medical ward (57%, 28/49) that approached statistical significance (5.62 ± 1.80 vs 4.78 ± 1.31, P = .06).
  
  
  CONCLUSIONS
  Intubation was observed in our emergency department in 29% of patients administered intramuscular ketamine for prehospital chemical restraint. There was a positive association between higher ketamine doses and both endotracheal intubation and hospital admission. Future research should aim to define the minimum effective ketamine dose for successful chemical restraint.
authors.affiliation: Regions Hospital, Department of Emergency Medical Services, Saint Paul, MN. Electronic address: Aaron.M.Burnett@healthpartners.com.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Burnett
authors.affiliation: Regions Hospital, Department of Emergency Medical Services, Saint Paul, MN.
authors.forename: Bjorn K
authors.initials: BK
authors.lastname: Peterson
authors.affiliation: Regions Hospital, Department of Clinical Toxicology, Saint Paul, MN.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Stellpflug
authors.affiliation: Regions Hospital, Department of Clinical Toxicology, Saint Paul, MN.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Engebretsen
authors.affiliation: Regions Hospital Emergency Medicine Residency, Saint Paul, MN.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Glasrud
authors.affiliation: University of Kansas College of Medicine, Kansas City, KS.
authors.forename: Jordan
authors.initials: J
authors.lastname: Marks
authors.affiliation: Regions Hospital, Department of Emergency Medical Services, Saint Paul, MN.
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Frascone
mesh_terms: D000328:Adult; D000778:Anesthetics, Dissociative / Q000008:administration & dosage*; D004636:Emergency Service, Hospital; D004638:Emergency Treatment; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007273:Injections, Intramuscular; D007442:Intubation, Intratracheal / Q000706:statistics & numerical data*; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000778:Anesthetics, Dissociative; D007649:Ketamine