Evaluating Wearable Smart Sensors for Continuous Measurement of Vital Signs in ICU
Conditions: Prematurity
Sponsor: Ann & Robert H Lurie Children's Hospital of Chicago

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Evaluating wearable smart sensors for 
continuous measurement of vital signs in 
ICU patients 
Principal Investigators: Aaron Hamvas, Debra Weese-Mayer, Sue Hong 
Sub-Investigators: Susan Slattery 
 
Protocol Date: 10/3/2024 
 
Funded in part by The Gerber Foundation (Grant 17-0683) 
 
 
 
 
 
 
 
 
 
 
 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
2 
 
 
Table of Contents 
1. 
Background and Significance3 
2. 
Study Hypothesis and Outcomes4 
2.1. 
Study Hypothesis4 
2.2. 
Outcome Measures4 
2.2.1. 
Primary Outcome5 
2.2.2. 
Secondary Outcome5 
3. 
Study Design5 
3.1. 
Target Population5 
3.2. 
Eligibility Criteria5 
3.2.1. 
Inclusion Criteria5 
3.2.2. 
Exclusion Criteria5 
3.3. 
Screening and consent6 
3.4. 
Recruitment Methods6 
3.5. 
Informed Consent Process6 
3.6. 
Study Procedures7 
3.7. 
Study Timeline9 
4. 
Study Safety9 
4.1. 
Privacy Protections9 
4.2. 
Potential Risks11 
4.3. 
Discontinuation Criteria12 
4.4. 
Patient Withdrawal12 
5. 
Statistical Analysis12 
5.1. 
Data Management and Quality Control12 
5.2. 
Statistical Plan12 
6. 
References13 
 
 
 
 
 
 
 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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1. Background and Significance 
In the intensive care units (ICUs), there is continuous monitoring of vital signs and patient 
physiology to detect developing instability and identify need for intervention. Despite significant 
advances in ICU monitoring and patient care, patients are still at high risk for cardiorespiratory 
compromise, which is associated with both acute and long-term consequences. Thus, a major 
ICU focus is utilizing these hemodynamic signals to identify when such risks will arise and 
provide timely intervention to maintain cardiovascular function and organ perfusion to avert 
secondary injury. To this end, real-time, continuous physiologic measures of these hemodynamic 
signals are crucial in the ICU.  
A current limitation of monitoring in the ICU is the lack of methods for continuous, non-invasive 
capture of blood pressure (BP).  In critically ill patients, clinicians rely on intra-arterial BP 
monitoring (IA-BP), whereby a catheter is inserted into the umbilical or other central or 
peripheral artery to provide continuous BP measurements. However, IA-BP procedures are 
invasive and lead to complications, thereby escalating risks of infection, bleeding, and 
thrombosis, increasing discomfort, and reducing contact. Thus IA-BP is only utilized in the most 
critically ill patients and is typically discontinued within 1 week. In the rest of the ICU 
population, only periodic cuff-based BP (CB-BP) measurements are obtained. CB-BP recordings 
are captured periodically, can be difficult to obtain, are disruptive, especially during sleep, and 
are highly unreliable. The lack of real-time and continuous monitoring of hemodynamic signals 
impairs the clinical team’s ability to detect and promptly respond to acute risks of 
decompensation, as well as obscuring longer-term patterns which may be sensitive markers of 
developing instability.  
The purpose of this study is to develop biocompatible electronic devices that will allow 
continuous, non-invasive hemodynamic measurements in the ICU (see sample figure 1 below). 
Members of this research team have developed innovative, wireless devices capable of being 
comfortably and continuously worn while recording diverse physiologic measurements. These 
devices have already demonstrated the capability to accurately capture hemodynamic 
measurements in healthy adult subjects (unpublished data, see figure 2 below). We propose to 1) 
 
Figure 1: Example of wearable sensor developed by the Roger’s group 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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optimize these devices for use in pediatric ICU patients, 2) demonstrate safety, reliability, and 
accuracy of these devices for continuous ICU hemodynamic signal measurements, including but 
not limited to BP, heart rate (HR), cerebral blood flow, temperature, and respiratory rate, and 3) 
demonstrate these devices are preferred by patients and parents to current measurement tools. 
Once validated, such sensors could fundamentally change the way patients are monitored in the 
ICU, eliminating risks associated with invasive monitoring, allowing continuous, real-time 
detection of clinically meaningful changes in ICU patients, advancing knowledge of 
hemodynamic signatures preceding clinically meaningful events, and ultimately offering 
opportunity to reduce morbidity and mortality in ICU patients. 
 
Figure 2:  Example of physiology measurements using wearable sensor.(A) ECG time 
waveforms for commercial cardiac monitoring device(red)and wearable sensor( blue). (B) 
Snapshot of average heart rate vs time using conventional ECG sensor (control) and wearable 
sensor in newborn. (C) Snapshot of oxygen saturation vs time using wearable sensor and 
standard oximetry sensor (control) in newborn. (D) PPG (blue)  and ECG (red) waveforms 
captured  simultaneously  and  synchronized  in  time  in  healthy  adult  subject.  Pulse arrival 
time (PAT) interval denoted in the waveform. (E) Pulse arrival time measurements during rest, 
Valsalva maneuver and release in adult subject. (F) Correlation of systolic blood pressure 
(measured with cuff-based BP device) and PAT measured with wearable sensor in adult subject. 
2. Study Hypothesis and Outcomes 
2.1. Study Hypothesis 
 
The main hypothesis of this study is that the wearable sensors will provide accurate, reliable, 
safe, and continuous capture of hemodynamic and physiologic signals in children, infants, 
and neonates.  
 
2.2. Outcome Measures 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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2.2.1.  Primary Outcome 
Primary outcome measures: Recorded measurements of BP as compared to the ICU 
standard of care monitoring, including both arterial line measurements and cuff-based 
measurements of the arm.  
2.2.2. Secondary Outcomes 
Secondary outcome measures: Recorded measurements of other physiologic signals such 
as HR, pain, temperature, cerebral blood flow,  aEEG-like waveforms, and respiratory 
rate as compared to ICU standard of care monitoring. Accelerometry will be captured 
using these devices, and in a subset of study participants, will be compared to video 
recordings to validate the accuracy of these devices for detecting body position and 
movement (as these are known to affect BP measurement). Devices may also evaluate 
subjects’ respiratory equipment. Questionnaire data examining parent opinions on use of 
wearable sensors compared to standard of care devices.   
3. Study Design 
3.1. Target Population 
Two distinct populations will be targeted for participation in this study. The first includes 
patients admitted to intensive care units (ICUs) including the pediatric intensive care unit 
(PICU), the neonatal intensive care unit (NICU), and the cardiac intensive care unit (CCU). 
This includes all ICUs at the Ann & Robert H. Lurie Children’s Hospital of Chicago (Lurie 
Children’s) and the NICU at Prentice Women’s Hospital (Prentice). The first target 
population will contribute primarily to the collection and validation of physiologic signals 
including BP, HR, pain, temperature, cerebral blood flow,  aEEG-like waveforms, and 
respiratory rate. The second target population includes any neonate, infant, or child whose 
parent or guardian consents to a one time visit to the Center for Autonomic Medicine in 
Pediatrics (CAMP) at Lurie Children’s. The second population will be more physically active 
than the ICU population and contribute primarily to the capture and validation of these same 
physiologic signals in the context of increased motion, which is known to produce artifact in 
such recordings. The wearable sensors must be tested in a range of patients across age groups 
in order to validate the signals and data recorded by the devices. This requires the inclusion 
of patients of various ages, including neonates, infants, and children.  
Up to 500 patients will be enrolled at Lurie Children’s and Prentice. 
3.2. Eligibility Criteria 
3.2.1.  Inclusion Criteria 
Participants must be admitted to one of the three ICUs at Lurie Children’s, admitted to 
the NICU at Prentice, or visiting CAMP with a parent or guardian. Anyone who satisfies 
one of these criteria and is under 18 years of age can participate.   
 
3.2.2.  Exclusion Criteria 
Anyone with a skin abnormality that would potentially increase risk of device use will be 
excluded.  Anyone 18 years or older will be excluded. In the ICU population, any patient 
or family determined by an attending physician or bedside care team to be too unstable 
(patient) or experiencing too much stress (family) will not be approached for recruitment.  

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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3.3. Screening and consent 
All ICU patients will be screened by the study team based on inclusion and exclusion criteria 
through review of electronic medical records. For screening at Prentice Women’s Hospital, 
screening criteria will be automatically applied through the use of the electronic data 
warehouse, and information from infants meeting this screening criteria will be transferred to 
the study team through electronic data warehouse.  A screening and enrollment log will be 
kept to track ICU patients/parents who have been approached and agreed or declined to 
participate in the study. The screening and enrollment log will be kept on the Northwestern 
University housed REDCap server. Only the study team will have access to this log. Non-
ICU participants will be screened through question and answer with a parent or guardian. 
3.4. Recruitment Methods 
 
The population of ICU patients will be recruited by the study team as follows: once the study 
team has identified an eligible patient, the study team will obtain permission to approach the 
eligible patient from the nurse or attending, ensuring that the ICU care team has sufficient 
time to assess the condition of the patient and determine the family’s approachability to 
discuss the study. If the family is felt to be approachable, the study staff will identify the best 
time to contact the family.  
The population of non-ICU participants will be recruited by the study team using IRB-
approved fliers distributed to affiliates of CAMP and posted in public locations in Chicago.   
 
3.5. Informed Consent Process 
All research staff will be trained on human subjects research education and good clinical 
practices, according to Lurie Children’s IRB standards.  A member of the study team will 
approach the prospective participant/family for consent using an IRB-approved consent form. 
Assent will be obtained from participants 12-17 years of age. If the prospective participant 
has a PCPC (Pediatric Cerebral Performance Category) score of ≥2 or has received sedative 
medications in the preceding 72 hours, assent will not be obtained. In the event that the 
participant is not capable of providing assent, a request for waiver of assent will be obtained 
from the IRB. If the cognitive capability of the participant changes during study participation 
and the participant is capable of providing assent, assent will be obtained within 48 hours.  
 
In a private space, the study will be discussed in detail, including the rationale, the specifics 
of data collection, our legal and ethical obligations and procedures to ensure confidentiality, 
and the questionnaires. The study team will also discuss the risks of participation. The  
prospective participant/family will also be informed that involvement or refusal will not 
affect the care of their child, and will be completely optional and anonymous. The 
prospective participant/family will be informed that the video monitoring of body position 
and movement is an optional part of the study. Written material describing the nature of this 
study and a copy of the Informed Consent document will be provided to each family. The 
prospective participant/family will then be left with the consent form to review and will be 
given an opportunity for private discussion. They will have the opportunity to ask questions. 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Once all questions are answered, the prospective participant/parents will be asked to discuss 
the study process in their own words before signing consent. To minimize the amount of time 
the study team spends in the participant’s bed space, a participant’s parent(s) may provide 
consent over the phone or a secure telecommunication platform such as Skype. The consent 
process as described above will not change. The family will be provided written materials 
describing the nature of the optional elements and given an opportunity for questions and 
private discussion. 
 
Consent obtained over the phone or secure telecommunication platform will be obtained 
according to institutional policy. A member of the study team will explain in detail and 
review the informed consent document(s) with the parent(s). If the parent(s) agree to 
participation, they will sign a copy of the informed consent document(s) and the study team 
member obtaining consent will sign a copy at the same time. The parent(s) will be required to 
send their signed document(s) to the study team by mail, fax, or email, and the two signature 
pages will be combined. The parent(s) will be provided a copy of the fully executed, signed 
informed consent document(s) by mail, fax, or email prior to any study procedures. 
 
For participants where a Waiver of Consent and/or HIPAA Authorization are used 
specifically for participants enrolled during COVID-19, the study team member approaching 
will review the entire consent form over the phone. In place of the signature, the study team 
member obtaining consent will ask the parents and/or adolescent about their interest to 
participate and get either a verbal consent (and/or assent) or refusal to participate.  
 
If verbal consent and/or assent is obtained, the study team member obtaining 
permission will document that all the parts of the consent process were reviewed, and 
verbal consent was obtained on to the consent and/or assent with date and time, and 
sign attesting permission was obtained, and consent process was reviewed in the 
designated sections. A signed and completed copy of the consent and/or assent with 
the information stated above will be provided to the parents either via email or regular 
mail. The provided copy of the consent will not be returned in any form to the study 
team to ensure their safety. 
 
3.6. Study Procedures 
Device application: In both the ICU and non-ICU study populations, standard-of-care devices 
will be used in all subjects and this data will be compared to that collected using novel 
wearable sensors suggested in this study. After participants are consented, multiple wearable 
sensors (up to 5) will be placed on the participant for the duration of the study.  Multiple 
devices are required to estimate BP.  One or more devices will be placed on the chest or 
back, and one or more additional devices will be placed peripherally (e.g. leg, foot, arm, 
hand, head, or ear). One or more additional devices may be placed on the patient's respiratory 
support device if applicable. Placing multiple devices will allow determination of which 
location provides the best signals in specific populations. These devices will be placed using 
a medical grade skin adhesive similar to the ones used in the ICUs, which will minimize the 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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risk of skin irritation or allergic reaction.  Alternatively, we are currently testing a “soft wrap-
around device” (similar to that currently used for blood pressure monitoring in the premature 
babies) with a sensor. The soft wrap-around device is composed of hypoallergenic cotton. 
Overlying this cotton, and not touching the subject’s skin, may include Coban wraps, paper 
tape, or a Velcro adhesion mechanism. Given the very small size of premature infant in the 
NICU, we may incorporate this new technology as needed in the NICU. In the ICU 
population, devices will be left in place for up to 72 hours, but will either be checked by the 
study or clinical team to ensure skin integrity and signal quality at least once every 24 hours. 
In the non-ICU population, devices will be left in place for up to 3 hours during a study visit 
to CAMP.  
We have recently upgraded a new firmware version activating the ability for the sensor to 
continuously measure bioimpedance for respiratory rate. This function does not require any 
modification to the physical device itself or the adhesive. However, the bioimpedance 
functionality does require delivery of low amplitude sinusoidal current through the electrodes 
of the chest unit. The frequency of the current is 4 kHz – a frequency range used typically for 
human bioimpedance measurements by FDA cleared systems. The maximum current 
delivered is 8 μA. These parameters are below commonly used body fat percentage 
impedance analyzers that are widely commercially available. Furthermore, bioimpedance is 
standard measurements in existing NICUs / PICUs/CICUs leveraging the ECG electrodes 
that are then displayed on standard of care monitors. Commercially bioimpedance devices 
that are FDA approved inject currents that are 10x greater than our system (e.g. the CoVa 
Monitoring System 2 for continuous wearable sensing of thoracic impedance). Finally, the 
parameters in our sensor follow IEC 60601-1-2 guidelines for electromagnetic safety. 
Video monitoring: In some participants, video monitoring of participant position and 
movement will be utilized during the study. This is an optional, additional part of the study in 
which families can choose to participate or not participate.  If a family chooses to participate, 
a video camera will be utilized to capture participant movement and position for the duration 
of the study in the ICU or at CAMP. 
Cuff-based blood pressure:  While the wearable sensors are attached to participants in both 
the ICU and non-ICU populations, the participants will also be monitored with the normal 
standard of care monitoring montage. In addition, during one 3- or 4-hour period while the 
wearable sensors are attached to the patient, a member of the study team may take the 
participant’s BP using the ICU standard cuff-based method every 15 minutes. Cuff-based 
measures typically happen every 15-60 minutes for standard clinical care, depending on the 
stability of the patient and physician discretion. In the ICU population, if a standard clinical 
cuff-based BP measure is taken during the 15-minute time epoch, the clinical measurements 
will be used rather than obtaining a separate research measurement. Outside of this 3- or 4-
hour window and for the remainder of the study duration in the ICU cohort, cuff-based BP 
measures will be made only as frequently as needed for standard clinical care.  
Skin temperature: While the wearable sensors are attached to the participant, skin 
temperatures will be taken using a standard infrared thermometer.  These measurements will 
be made at the same interval as the above cuff-based BP, over the same 4-hour period by a 
member of the study team.  Outside of this 4-hour window, no skin temperature measures 
will be made for research purposes.   

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Device data: Wearable sensors can stream data continuously using near field communication 
(NFC) or Bluetooth technology. An encrypted laptop, iPad, or similar device will be left in 
the patient room and used to capture the continuous data stream from the wearable sensor.  
Additionally, wearable sensors can include onboard memory, and physiologic streams may 
be recorded to this onboard memory until transfer to an encrypted laptop for analysis.   
Standard of care data: In all participants where data from standard of care monitoring is 
captured and stored using the BedMasterEx system (all PICU and CCU beds, some NICU 
beds), and the Sickbay™ platform (CCU beds), this data will be used for comparison to data 
captured using EWP.  In any participants where data are not captured and stored using the 
BedMasterEx system or Sickbay™ platform, video recordings will be made of the Phillips 
monitors using an encrypted mobile device.  Within 48 hours, videos will be downloaded and 
transferred to a HIPAA secure server.  In NICU patients without BedMasterEx data, the 
Somnostar system may be used to capture data for up to 4 hours of the study. All study data 
will be stored on an encrypted laptop and/or secure network for analysis. We will continue to 
follow patients for 5 years by collecting standard of care data entered into their electronic 
medical record. 
Skin Integrity: Before and after wearable sensors are placed on the participant, the 
participant’s skin integrity will be monitored using the ICU standard protocol, either the 
Braden Q scale (≥6 months of age) and/or Neonatal Skin Risk Assessment Scale (NSRAS; 
<6 months of age). Additionally, a validated skin integrity scale will be used to score 
participants’ skin condition at sensor placement site before sensor placement and 
immediately after sensor removal. At both of these time points, photographs may be taken of 
the participants’ skin at the site of sensor placement to document any skin changes that occur 
during the period of wearable sensor wear. No faces will be photographed. One or more 
additional skin scores and photographs may be performed/taken between 30 minutes and 48 
hours after sensor removal, as deemed necessary by the study and/or clinical team. The study 
team will consult the ICU bedside care team or CAMP clinical team within 1 hour for any 
concerning changes in skin integrity.  
Questionnaires: After the study period ends, the parents may be approached to complete the 
questionnaires.  These questionnaires will take less than 10 minutes to complete and are 
meant to assess opinions on use of these devices in the ICUs.  These questionnaires will be 
completed using REDCap.  If preferred, the family will complete a printed version of the 
REDCap questionnaire and this data will then be entered by study staff into the REDCap 
server.  All questionnaire data will be stored on the secure REDCap server housed by 
Northwestern University.   
3.7. Study Timeline 
Study recruitment, data collection, and ongoing analysis: 1-30 months 
Final analysis and report preparation: 6 months 
4. Study Safety 
4.1. Privacy Protections 
The study team will take measures to protect the privacy and confidentiality of participants. 
The plan to protect patient privacy includes approaching and consenting participants in a 
private room. Study procedures will be done in the privacy of the patient rooms in the ICU. 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Study participation discussions will be limited to members of the study staff and the involved 
participants. 
Participant data will be coded with study identifier only. All data obtained from the bedside 
monitors will be stored on the Azure Cloud (maintained by Data Analytics Reporting (DAR) 
at Lurie Children’s). All data obtained using wearable sensors will be stored on an encrypted 
laptop and secure network for later analysis. All questionnaire responses will be collected via 
Research Electronic Data Capture (REDCap) hosted by Northwestern University. When 
preferred, parents can fill in questionnaires on paper, and these will be transferred to 
REDCap by study staff after collection.    
To minimize the risks, only the minimum data necessary to complete the study will be 
collected on each study participant.  
Data to be collected include:  
• 
Demographic data (age, gender, race, sex, gestational age (in participants <1 year of age, 
only)) 
 
• 
Body mass index, height, weight, and body surface area 
 
• 
Diagnosis for admission to the ICU  
 
• 
Medications during the study 
 
• 
All skin integrity scores (either the Braden Q scale (≥6 months of age) and/or Neonatal 
Skin Risk Assessment Scale (NSRAS; <6 months of age) for 24 hours before, during, and 24 
hours after the sensor study 
 
• 
All pain scores (Face, Legs, Activity, Cry, Consolability scale (FLACC), State 
Behavioral Score (SBS), Neonatal Pain, Agitation and Sedation Scale (NPASS), Neonatal 
Facial Coding System (NFCS) 
• 
Alarms/clinical events during the study 
 
• 
Video monitoring of patient position and movement (optional) 
 
• 
Data generated by the wearable sensors and standard of care monitoring devices which 
will include standard physiologic measurements such as BP, HR, blood oxygenation, cerebral 
blood flow, pain, temperature, movement, and respiratory rate  
 
Photographs will be labeled only by study code, and will not include subject’s face. Video 
may include the subject’s face, but all videos will be scored for position and movement 
within 1 month of recording, and will be deleted after scoring.  All photos and videos will be 
stored on a password protected server accessed by a password protected computer. 
Only authorized personnel listed in the IRB application will have access to study data. The 
screening and enrollment log used contain the code link, and this file will be stored on the 
REDCap server and will have access limited to the study team. The link between the 
participants and their study identifier will be destroyed at the conclusion of this study, so all 
remaining data will be fully de-identified.  

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Data transferred to the study team by the NU electronic data warehouse for patients meeting 
screening criteria in the Prentice NICU will be downloaded onto the Lurie Children's 
Hospital server. This data file will be used for up to one week to allow the screening process 
to take place, then will be deleted.  
Confidentiality will be maintained with all of the medical records of this study. Subject 
records will be kept in a locked cabinet, under the control of the Principal Investigator. The 
subject will also be assigned a code in the data sheets so that the records on the computer will 
be kept confidential.  
Potential Risks 
Data risks: The risks involved with this research are minimal and include loss of privacy and 
confidentiality. The safeguards in place for de-identifying and storing data should mitigate 
this risk. To minimize this risk, access to the data is restricted to the PI and key personnel on 
the research team. Data will be coded, stored without identifiers. Video data, which may 
include identifiable images, will be stored on an encrypted device only until position and 
scoring analysis take place, and will then be deleted. Data collected throughout this study 
will remain on the hospital network and the REDCap server, and be under the same 
safeguards in place for clinical data. Any data stored for future studies will be further de-
identified, after study conclusion. Any data transferred off of the hospital network for 
statistical/data analysis will be fully de-identified before transfer.   
The clinical data and data from the wearable sensors will be collected and stored to the 
secure Lurie Children’s Hospital server that is subject to security and access protections 
within the hospital intranet, including firewall and password access protection restricted to 
the PIs, Co-Is and study coordinators. Data will be tied to participant codes without patient 
identifiers. The participant code key will be maintained separately under physical (locked 
office) and electronic (additional password) access controls and accessible only by the PI and 
research team. 
Skin discomfort/irritation risks: There is a risk of discomfort or irritation from adhesives and 
wearable sensors. It is possible that this additional sensor may contribute to skin irritation or 
discomfort or that the additional handling required in placing these sensors may be 
temporarily disruptive for the participants. Study staff and/or the clinical team will check on 
the participants in the ICU at least once every 24 hours to monitor for signs of discomfort, 
irritation, or allergic reaction. Sites of sensor placement will be assessed clinically before, 
immediately after removal, and at one or more additional time points (as deemed necessary 
by clinical team) between 30 minutes and 48 hours after removal for skin alteration by a 
trained member of the research team using a validated skin integrity scale Photographs will 
be taken at baseline and after study; skin changes during the period of wearable sensor use or 
at subsequent time points will be documented photographically. If a reaction occurs, the 
sensor at the site will be discontinued, and the photograph will be reviewed by a member of 
the NICU/PICU/CICU clinical team for decision-making about management. 
Photograph risks: No faces will be photographed.  There is a possibility that subjects may be 
able to be identified from the photographs that will be taken for the study. 
Video risks: Videos will be an optional part of the study, and may contain identifiable 
information.  Videos will be stored on an encrypted device.  Videos will be scored by a 
member of the research team for position and movement, and video will be deleted after 
scoring.   

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Survey risks: Some questions may make parents uncomfortable or upset. Participants do not 
have to answer these questions if they do not want to. 
4.2. Discontinuation Criteria 
A participant may be discontinued if the participant is unwilling or unable to tolerate the 
wearable sensors. Examples may include adverse reactions to the adhesive on the wearable 
sensors or a patient removing the wearable sensors. The bedside clinical team or family can 
also request discontinuation at any time.  Families participating in the video monitoring can 
request discontinuation of the video monitoring aspect of this study at any time during the 
study.  
4.3. Patient Withdrawal 
 
Any participants withdrawn from the study will have the wearable sensors removed 
immediately. Any data collected prior to the withdrawal will remain a part of the study, and 
this data will be coded. 
 
5. Statistical Analysis 
5.1. Data Management and Quality Control 
Clinical data will be obtained from the electronic health records for consented participants. 
Data will be extracted both manually and electronically from the electronic records. Data 
from the bedside monitors will be retrieved from the Azure cloud at Lurie Children’s. The 
continuous data from the wearable sensors will be directly transmitted and stored on the 
network-encrypted laptop. Video data will be directly transmitted and stored on the same 
network-encrypted laptop Continuous data measurements will be cleaned and binned by the 
statistical/data analyst. The cuff-based measures will be assessed by the statistical/data 
analyst to ensure data quality and control. Questionnaire data will be stored on the REDCap 
server at Northwestern University.  
5.2. Statistical Plan 
Measurements made through clinical standard of care will be compared to the measurements 
recorded by the wearable sensors. Distribution checks for normality and data accuracy will 
be completed for each individual and for the entire study prior to all analyses.  For 
continuous measures of physiology, 30 second epochs will be defined for each method for 
comparison.  For non-continuous CB-BP measures, each measure will be matched and 
compared to the 30-second epoch during which the measure was captured.  We will further 
check for time lags in the relationships between methods by applying peak-picking methods 
to lagged regression plots for all pairs of measures. 
Agreement and correlation of wearable sensor measures to standard of care measures will be 
assessed in two ways. First, Bland–Altman plots will be created to assess agreement between 
each measurement system via bias and precision, which reflect the mean or average 
difference between two methods and the variation in these differences, respectively. Our 
second method consists of individual correlations between methods assessed for each person. 
This correlational method will supplement additional methods, and can be directly 
transformed to variance shared between wearable sensor and standard of care measures, a 
common metric of reliability of any measure. 

BP in the ICU 
 
PI: Hamvas, Weese-Mayer, Hong-Routson; Sub-Investigators: Slattery 
Study Protocol 
 
DRAFT DATE: 10/3/2024 
 
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Formal tests of bias, precision, and correlations: While the above methods will yield useful 
statistics, they need to be extended to deal with the structured nature of our data. Specifically, 
our data are clustered, meaning that we have multiple observations within each person and 
multiple people in our sample, which violates standard independence assumptions inherent to 
many models. We propose to estimate bias and correlation/reliability using multi-level 
models, which yield the same statistics discussed above but account for the fact that 
observations taken from the same patient are more related than comparisons involving 
different patients.   
Statistical power: The large amount of within-person data provides incredibly high statistical 
power for all planned and many secondary data analyses, allowing this data set to answer all 
proposed questions. Previous work on power in multilevel models found greater than 99% 
power to detect associations with the planned observations suggested here within comparable 
nested designs.  
6. References 
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St Peter D, Gandy C, Hoffman SB. Hypotension and Adverse Outcomes in 
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