Accuracy Of Patient-Reported Body Weight On A Mobile Stroke Unit Compared To Measured Body Weight And Alteplase Dosing Implications

Background: Administration of intravenous tissue plasminogen activator is standard of care for patients presenting with acute ischemic stroke. The optimal dose, per American Heart Association guidelines, is 0.9 mg/kg of IV alteplase to maximize clinical effectiveness while minimizing complications. With the integration of mobile stroke units (MSUs), IV alteplase is more frequently administered in the prehospital setting. Patient-reported body weights, instead of measured body weights, remain commonplace in MSUs due to logistical challenges of accurate weighing systems on MSUs. It is unknown whether patient-reported weights can be safely used, as previous cohort studies have reported that 16% to 33% of patient-reported weights are inaccurate. Methods: We retrospectively analyzed all MSU patients from January 2018 to July 2021 who were given IV alteplase and subsequently transported to one of our network hospitals. Patient or family-reported weights used in the MSU for IV alteplase administration and subsequent measured patient weights were retrospectively collected. Reported weights were deemed accurate if within 10% of the measured patient weights. Results: A total of 66 patients received IV alteplase on the MSU. The median age of these patients was 64 years (interquartile range (IQR) 53-78). Forty eight percent of IV alteplase treated patients were women. Median last known well to IV alteplase bolus time was 58.5 minutes (IQR 47- 92). Twenty of the 66 patients had a reported body weight greater than 100 kg, all of whom were confirmed to weigh more than 100 kg at hospital arrival. Of the remaining 46 patients, the median administered dose of IV alteplase was 0.90 mg/kg (IQR 0.88-0.95). Seventeen percent of patients were inaccurately dosed; 4% of patients were underdosed and 13% of patients were overdosed. One patient who was overdosed (1.01 mg/kg) had symptomatic intracranial hemorrhage. Conclusion: Within our single-center cohort, patient-reported weights were an accurate surrogate for measured patient weights for administration of IV tPA in the prehospital MSU setting. However, patient-reported weights may increase dosing errors which could have both efficacy and safety implications.