title: Tissue plasminogen activator overdose in acute ischemic stroke patients linked to poorer functional outcomes.
abstract: BACKGROUND
  The dose of intravenous tissue plasminogen activator (tPA) administered in acute ischemic stroke patients is calculated using the patient's weight (0.9 mg/kg). Patients are rarely weighed before treatment in actual practice, although overestimating patient weights leads to higher doses of tPA, which may adversely influence outcome.
  
  
  METHODS
  We investigated the weight used to calculate the dose of tPA compared to the actual measured weight in consecutive acute ischemic stroke patients treated over a 4-year period at our center. The rate of intracranial hemorrhage (ICH), discharge modified Rankin Scale (mRS) score, and mortality at 3 months were compared between groups, according to accuracy of the dose of tPA.
  
  
  RESULTS
  We found that 140 of 164 (85%) acute ischemic stroke patients treated with tPA had a measured weight documented in the chart after treatment. Of these, 13 patients received ≥1.0 mg/kg and 16 patients received ≤0.8 mg/kg, based on a comparison of the weight used for the tPA dose calculation and the subsequent measured weight. Four of 13 (31%) patients treated with ≥1.0 mg/kg of tPA developed ICH. Patients who inadvertently received higher doses of tPA had a lower likelihood of a good functional outcome at discharge (mRS score 0-2; 0% v 34%; P = .009). No difference in 3-month mortality was observed, although patients who were not weighed in hospital had a threefold increase in discharge mortality (21% v 7%; P = .019).
  
  
  CONCLUSIONS
  Our findings provide support for the practice of accurately weighing all acute ischemic stroke patients before thrombolysis.
authors: Division of Neurology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Central South Ontario Regional Stroke Centre, Hamilton General Hospital-Hamilton Health Sciences, Hamilton, Ontario, Canada. Electronic address: sahlas@mcmaster.ca.
authors: Demetrios J
authors: DJ
authors: Sahlas
authors: Central South Ontario Regional Stroke Centre, Hamilton General Hospital-Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors: Linda
authors: L
authors: Gould
authors: Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors: Richard H
authors: RH
authors: Swartz
authors: Central South Ontario Regional Stroke Centre, Hamilton General Hospital-Hamilton Health Sciences, Hamilton, Ontario, Canada; Division of General Internal Medicine, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors: Naufal
authors: N
authors: Mohammed
authors: Central South Ontario Regional Stroke Centre, Hamilton General Hospital-Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors: Rhonda
authors: R
authors: McNicoll-Whiteman
authors: School of Graduate Studies, Global Health Program, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors: Fahd
authors: F
authors: Naufal
authors: Division of Neurology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada; Central South Ontario Regional Stroke Centre, Hamilton General Hospital-Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors: Wieslaw
authors: W
authors: Oczkowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight; D002545:Brain Ischemia / Q000150:complications* / Q000188:drug therapy / Q000401:mortality; D062787:Drug Overdose; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage* / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D020300:Intracranial Hemorrhages / Q000453:epidemiology / Q000209:etiology; D008297:Male; D019300:Medical Errors; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications* / Q000188:drug therapy / Q000401:mortality; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage* / Q000009:adverse effects* / Q000627:therapeutic use; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: Acute stroke; medical errors; thrombolytic therapy; tissue plasminogen activator