This clinical trial tests the feasibility and safety of a wearable biosensor patch for non-invasive monitoring for patients undergoing abdominal or chest surgery. Wearable biosensor patches have been developed by researchers to provide a non-invasive way to monitor substances that are normally checked using blood tests. This may reduce the need for frequent blood draws. The patches use gentle electrical stimulation to produce sweat and tiny built-in sensors to measure substances such as glucose, creatinine, and markers of inflammation, as well as oxygen and carbon dioxide levels. The wearable biosensor patch may be a feasible and safe way to monitor patients undergoing abdominal or chest surgery.

PRIMARY OBJECTIVE:

I. To evaluate the feasibility of data collection using wearable postoperative biosensor patch.

SECONDARY OBJECTIVES:

I. To evaluate patient acceptability with using the wearable biosensor patch. II. To evaluate the safety of the wearable biosensor patch. III. To assess processes and resources needed to deploy the wearable biosensor patches postoperatively.

EXPLORATORY OBJECTIVES:

I. To explore the consistency of sweat analyte concentrations obtained using the wearable biosensor patch and a standard sweat collector.

II. To explore the accuracy of sweat-derived analyte concentrations relative to peripheral blood measurements (gold standard).

III. To explore the feasibility of intraoperative blood gas monitoring using a transcutaneous biosensor patch measuring oxygen (O₂) and carbon dioxide (CO₂).

IV. To explore the accuracy of O₂ and CO₂ concentrations obtained from the transcutaneous biosensor patch relative to paired intraoperative blood gas measurements (gold standard).

OUTLINE:

Patients have the wearable biosensor patch placed on the upper back or shoulder during surgery and wear it for the duration of the surgery to monitor oxygen and carbon dioxide levels. Starting the day after surgery, patients wear a biosensor patch on their wrist along with a sweat collecting chamber for 2-4 hours, up to twice daily, for up to 3 days post-operatively.

After completion of study intervention, patients may be followed up for up to 1 year.

Inclusion Criteria:

• Age ≥ 18 years
• Scheduled to have an elective abdominal or thoracic operation with anticipated post-operative hospitalization ≥ 3 days
• Willingness to provide sweat samples, complete surveys, and permit review of medical records for research use
• Ability to consent to the study procedures

Exclusion Criteria:

• Carbachol or pilocarpine allergy
• Adhesive/tape allergy
• Damaged or irritated skin on one or both wrists that prohibits placement of the biosensor and sweat collecting devices
• Pregnant women
• Children less than 18 years of age