Augmentation of Electrocardiographic QRS R-Amplitude Precedes Radiocontrast-Induced Hypotension during Mobile Computed Tomography Scanning

Hye-Mee Kwon; Sung-Hoon Kim; Hee-Sun Park; Yong-Seok Park; Young-Jin Moon; Jae-Man Kim; Robert Thiele

doi:10.3390/jcm8040505

Augmentation of Electrocardiographic QRS R-Amplitude Precedes Radiocontrast-Induced Hypotension during Mobile Computed Tomography Scanning

J Clin Med. 2019 Apr 12;8(4):505. doi: 10.3390/jcm8040505.

Authors

Hye-Mee Kwon¹, Sung-Hoon Kim^{1

2}, Hee-Sun Park¹, Yong-Seok Park¹, Young-Jin Moon¹, Jae-Man Kim¹, Robert Thiele³

Affiliations

¹ Biosignal Analysis and Perioperative Outcome Research Laboratory, Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.dd
² Health Innovation Bigdata Center, Asan Institute for Lifesciences, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.
³ Departments of Anesthesiology and Biomedical Engineering, University of Virginia School of Medicine, Pinn Hall 1232, Charlottesville, VA 22908, USA.

Abstract

Although intravenous administration of contrast media may trigger a variety of adverse reactions, sedated patients undergoing computed tomography (CT) scanning usually are not able to report their symptoms, which may delay detection of adverse reactions. Furthermore, changes in vital signs cannot be typically measured during mobile CT scanning, which worsens the situation. We aimed to characterize contrast-related hemodynamic changes that occur during mobile CT scanning and predict sudden hypotension based on subtle but robust changes in the electrocardiogram (ECG). We analyzed the digitized hemodynamic data of 20 consecutive patients who underwent clipping of a cerebral artery aneurysm and contrast-enhanced CT scanning following the surgical procedure. Hemodynamic variables, including ECG findings, invasive blood pressure (BP), pulse oximetry results, capnography findings, cardiac output, and systemic vascular resistance, were monitored simultaneously. We measured morphological changes in ECG-derived parameters, including the R-R interval, ST height, and QRS R-amplitude, on a beat-to-beat basis, and evaluated the correlation between those parameters and hemodynamic changes. After the radiocontrast injection, systolic BP decreased by a median 53 mmHg from baseline and spontaneously recovered after 63 ± 19 s. An increase in QRS R-amplitude (median 0.43 mV) occurred 25 ± 10 s before hypotension developed. The receiver operating characteristic curve showed that a 16% increase in QRS R-amplitude can predict a decrease in systolic BP of >25% (area under the curve 0.852). Increased cardiac output (median delta 2.7 L/min from baseline) and decreased systemic vascular resistance (median delta 857 dyn·s/cm⁵ from baseline) were also observed during hypotension. During mobile CT scanning, profound but transient hypotension can be observed, associated with decreased vascular resistance. Augmentation of QRS R-amplitude from an ECG represents a sensitive surrogate for onset of a hypotensive episode after contrast injection, thereby serving as a simple and continuous noninvasive hemodynamic monitoring tool.

Keywords: QRS-R amplitude; computed tomography; contrast agent; electrocardiogram.