January 1, 1994
View Full PaperIntravenous Cannulation alters the Specificity of Head-up Tilt Testing for Vasovagal Syncope in Elderly Patients
Key Result
Intravenous cannulation during head-up tilt testing induced symptomatic hypotension in 50% of healthy elderly subjects, compared to 0% when non-cannulated.
Study Design
Type
Observational (n=10)
Structured PICO
Does intravenous cannulation alter the response to head-up tilt testing in healthy elderly subjects?
P
Population
10 healthy elderly subjects
I
Intervention
Intravenous cannulation prior to head-up tilt testing
C
Comparator
Head-up tilt testing without intravenous cannulation
O
Outcome
Development of symptomatic hypotension during head-up tilt testingsurrogate
Intravenous cannulation alone can induce false-positive responses (symptomatic hypotension) during head-up tilt testing in healthy elderly subjects, suggesting caution when interpreting positive responses with intravenous isoprenaline.
Main Result
Absolute Event Rate: 50% vs 0%
Abstract
Prolonged head-up tilt is increasingly used as a diagnostic test for vasovagal syncope. Its sensitivity is reported to increase with the concurrent administration of intravenous isoprenaline. False-positive responses are common in young controls particularly following intravascular instrumentation. We studied the influence of intravenous cannulation alone on responses to head-up tilt in ten healthy elderly subjects. All remained asymptomatic during tilt when non-cannulated whilst five developed symptomatic hypotension following cannulation. Thus, intravascular instrumentation influences responses to held-up tilt in elderly subjects; the significance of positive responses obtained using intravenous isoprenaline in this age group requires further evaluation.