User profiles for "author:Walter Karlen"

Walter Karlen

Mobile Health & AI Systems for Medicine
Verified email at ieee.org
Cited by 4026

Capillary refill time: is it still a useful clinical sign?

A Pickard, W Karlen, JM Ansermino - Anesthesia & Analgesia, 2011 - journals.lww.com
Capillary refill time (CRT) is widely used by health care workers as part of the rapid,
structured cardiopulmonary assessment of critically ill patients. Measurement involves the …

[HTML][HTML] Ethics review of big data research: What should stay and what should be reformed?

A Ferretti, M Ienca, M Sheehan, A Blasimme… - BMC medical …, 2021 - Springer
Background Ethics review is the process of assessing the ethics of research involving
humans. The Ethics Review Committee (ERC) is the key oversight mechanism designated to …

Remote health diagnosis and monitoring in the time of COVID-19

JA Behar, C Liu, K Kotzen, K Tsutsui… - Physiological …, 2020 - iopscience.iop.org
Abstract Coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2), is rapidly spreading across the globe. The clinical spectrum of …

Multiparameter respiratory rate estimation from the photoplethysmogram

W Karlen, S Raman, JM Ansermino… - IEEE Transactions on …, 2013 - ieeexplore.ieee.org
We present a novel method for estimating respiratory rate in real time from the
photoplethysmogram (PPG) obtained from pulse oximetry. Three respiratory-induced …

Cxplain: Causal explanations for model interpretation under uncertainty

P Schwab, W Karlen - Advances in neural information …, 2019 - proceedings.neurips.cc
Feature importance estimates that inform users about the degree to which given inputs
influence the output of a predictive model are crucial for understanding, validating, and …

Sleep and wake classification with ECG and respiratory effort signals

W Karlen, C Mattiussi… - IEEE Transactions on …, 2009 - ieeexplore.ieee.org
We describe a method for the online classification of sleep/wake states based on
cardiorespiratory signals produced by wearable sensors. The method was conceived in …

Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation

W Karlen, K Kobayashi, JM Ansermino… - Physiological …, 2012 - iopscience.iop.org
Pulse oximeters are monitors that noninvasively measure heart rate and blood oxygen
saturation (SpO 2). Unfortunately, pulse oximetry is prone to artifacts which negatively …

CapnoBase: Signal database and tools to collect, share and annotate respiratory signals

W Karlen, M Turner, E Cooke… - … Annual meeting of …, 2010 - research-collection.ethz.ch
Methods Following institutional ethics approval, an in vivo data set was recorded and
extracted from 59 routine pediatric surgeries at the British Columbia Children's Hospital and …

[HTML][HTML] Development of a screening tool for sleep disordered breathing in children using the phone Oximeter™

A Garde, P Dehkordi, W Karlen, D Wensley… - PloS one, 2014 - journals.plos.org
Background Sleep disordered breathing (SDB) can lead to daytime sleepiness, growth
failure and developmental delay in children. Polysomnography (PSG), the gold standard to …

[HTML][HTML] Estimating respiratory and heart rates from the correntropy spectral density of the photoplethysmogram

A Garde, W Karlen, JM Ansermino, GA Dumont - PloS one, 2014 - journals.plos.org
The photoplethysmogram (PPG) obtained from pulse oximetry measures local variations of
blood volume in tissues, reflecting the peripheral pulse modulated by heart activity …