Wearable Sweat Sensor for High-Concentration Lactate Monitoring in Critically Ill Patients

Development and Preliminary Clinical Validation of a Wearable Sweat Sensor for High-Concentration Lactate Monitoring in Critically Ill Patients: A Prospective Cohort Study

Blood lactate level is closely associated with the prognosis of patients with sepsis and septic shock. Clinical guidelines explicitly recommend blood lactate monitoring in septic patients and lactate-guided fluid resuscitation when lactate levels are elevated. Dynamic monitoring of serum lactate changes and calculation of lactate clearance can more accurately reflect the dynamic changes in tissue oxygen supply and consumption, and can be used to evaluate tissue perfusion and oxygen metabolism. However, most existing wearable sweat sensors have a detection range of only 0-20 mmol/L, which is suitable only for monitoring during exercise under normal physiological conditions and cannot meet the clinical monitoring needs of patients with hyperlactatemia. In addition, current wearable sweat lactate sensors suffer from poor reproducibility and are easily affected by environmental factors and complex sweat composition, which represent major obstacles to clinical translation. Therefore, this project aims to develop a wearable sweat sensor for high-concentration lactate monitoring and to conduct preliminary clinical validation in critically ill patients, by simultaneously measuring blood and sweat lactate concentrations and establishing their correlation, with the goal of achieving non-invasive and convenient disease monitoring through sweat biomarker detection.

Study Overview

• Status: Not yet recruiting
• Conditions: Sepsis; Severe Sepsis With Septic Shock; Severe Sepsis Without Septic Shock
• Intervention / Treatment: Device: High-Concentration Sweat Lactate Wearable Monitoring Device; Device: Commercial Sweat Collection Device (HELA)

Detailed Description

Over the past decade, the wearable electronics industry has seen exponential growth in demand for continuous health monitoring technologies. From smartwatches to electronic skin, wearable devices have expanded their focus beyond biophysical signals to include biochemical signals such as small-molecule substances and macromolecular proteins in sweat. However, wearable sweat sensing technology still faces significant challenges, including discomfort and skin irritation caused by sweat-inducing materials, effective sweat extraction and collection capability, continuity and reliability of sweat sensing data, sensor calibration, and understanding of sweat analysis methods to discover clinically valuable new biomarkers. Therefore, how to translate wearable sweat monitoring devices into stable, continuous clinical use-matching the needs of health monitoring, disease diagnosis, and precision medicine-remains a research hotspot and challenge.

Lactate is abundant in sweat and is a hallmark product of anaerobic metabolism. Abnormal lactate levels are associated with multiple diseases. As an important marker of tissue perfusion, blood lactate level is closely associated with the prognosis of patients with severe sepsis and septic shock. Clinical guidelines explicitly recommend blood lactate monitoring in septic patients and lactate-guided fluid resuscitation when lactate levels are elevated. Dynamic monitoring of serum lactate changes and calculation of lactate clearance can more accurately reflect dynamic changes in tissue oxygen supply and consumption, and evaluate tissue perfusion and oxygen metabolism. Studies have shown that a lactate clearance rate ≥10% within 6 hours of resuscitation may predict lower mortality in septic patients. Clinical research has also shown that serum lactate concentration can be used to guide clinical treatment decisions, serving as both a therapeutic target and a prognostic indicator. However, most existing wearable sweat sensors have a detection limit of only 0-20 mmol/L, suitable only for exercise monitoring under normal physiological conditions, and cannot meet the clinical need for monitoring hyperlactatemia patients, whose lactate levels can reach up to 100 mmol/L. In addition, current wearable sweat lactate sensors suffer from poor reproducibility and are easily affected by environmental factors and complex sweat composition, posing major obstacles to clinical translation.

Based on this, the investigators have designed an intelligent wearable device for high-concentration sweat lactate monitoring, which includes a lactate detection electrode, a pH detection electrode, a temperature detection electrode, a sweat-stimulating electrode, a microfluidic sweat collection device, a hydrogel patch for inducing sweating, a flexible integrated circuit, and an intelligent display system. This wearable sweat lactate sensor achieves a detection range of up to 100 mmol/L, with a sensitivity of 89 nA/(cm²·mM) and a response time of 150 seconds, and achieves non-exercise-induced sweating through electrical stimulation. In addition, given the sensitivity of the lactate oxidase sensor to temperature and pH, corresponding temperature and pH sensors have been designed for calibration purposes.

This study is a prospective cohort study to be conducted in the surgical intensive care unit (ICU). Critically ill patients with blood lactate concentration >1.5 mmol/L will be enrolled and divided into two groups: (1) a sweat collection group, in which sweat will be collected using a commercial sweat collection device (HELA) for laboratory (ELISA) analysis; and (2) a wearable device monitoring group, in which patients will wear the investigator-designed wireless wearable sweat sensor for real-time monitoring. Clinical data, including medical history, imaging, and laboratory results, will be collected concurrently. The correlation between sweat and blood lactate concentrations, as well as the accuracy and safety of the wearable device, will be evaluated using Pearson correlation analysis.

• Study Type: Observational
• Enrollment (Estimated): 86

Contacts and Locations

• Study Contact: Name: Kai Qu; Phone Number: +8613609117104; Email: qukai001@xjtu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Critically ill patients admitted to the surgical intensive care unit (ICU) of the First Affiliated Hospital of Xi'an Jiaotong University with blood lactate concentration greater than 1.5 mmol/L, indicating hyperlactatemia associated with conditions such as sepsis or septic shock. Eligible patients will be assigned to either a sweat collection group or a wearable device monitoring group for concurrent measurement of blood and sweat lactate concentrations.

Description

Inclusion Criteria:

• Admitted to the surgical intensive care unit (ICU)
• Blood lactate concentration > 1.5 mmol/L
• Age ≥ 16 years
• Willing to voluntarily donate samples and provide signed informed consent

Exclusion Criteria:

• Pregnant women
• Pre-existing hematologic disease prior to infection
• Long-term use of immunosuppressive agents or presence of immunodeficiency
• Skin too dry to allow adequate sweat collection

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Wearable Device Monitoring Group	Device: High-Concentration Sweat Lactate Wearable Monitoring Device; A flexible wireless wearable device integrating a lactate detection electrode, pH detection electrode, temperature detection electrode, sweat-stimulating electrode, microfluidic sweat collection module, sweat-inducing hydrogel patch, and flexible integrated circuit with an intelligent display system. The device induces localized non-exercise sweating via electrical stimulation and enables real-time detection of sweat lactate concentration up to 100 mmol/L.
Sweat Collection Group	Device: Commercial Sweat Collection Device (HELA); A commercially available sweat collection device (HELA) used to collect sweat samples from critically ill patients at the time of routine blood draws for clinical lactate testing. Collected sweat samples are subsequently analyzed for lactate concentration using ELISA in the laboratory.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sweat Lactate Concentration	Sweat lactate concentration will be measured in critically ill patients with blood lactate concentration >1.5 mmol/L, either via laboratory (ELISA) analysis of sweat samples collected using a commercial sweat collection device, or via real-time detection using the investigator-designed wearable sweat sensor. The correlation between sweat and blood lactate concentrations will be analyzed using Pearson correlation to establish the sweat lactate concentration range corresponding to hyperlactatemia.	At the time of enrollment, concurrent with clinical blood lactate testing (within the ICU stay, up to approximately 12 months of enrollment period)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation Between Sweat Lactate Concentration Measured by the Wearable Device and Blood Lactate Concentration Measured by Standard Clinical Testing	Sweat lactate concentration (mmol/L) obtained from the wearable device will be compared with corresponding blood lactate concentration (mmol/L) obtained through standard clinical laboratory testing, using correlation analysis (e.g., Pearson or Spearman correlation coefficient) and Bland-Altman agreement analysis.	Throughout the device-monitoring period during ICU stay (up to 12 months)
Number of Participants With Device-Related Skin Adverse Events	Number of participants experiencing skin irritation, discomfort, or other adverse events at the sensor application site, assessed through clinical observation during device use.	Throughout the device-monitoring period during ICU stay (up to 12 months)

Collaborators and Investigators

• Sponsor: Second Affiliated Hospital of Xi'an Jiaotong University

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): October 1, 2029

Study Registration Dates

• First Submitted: July 13, 2026
• First Submitted That Met QC Criteria: July 20, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 20, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Systemic Inflammatory Response Syndrome; Inflammation; Pathological Conditions, Signs and Symptoms; Sepsis
• Other Study ID Numbers: XJTUSAH-WB-001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No