Exploring Biomarkers in the Heat and Moisture Exchange Filters (HMEPRO)

When patients undergo major surgery, they are connected to a ventilator during anesthesia. A heat and moisture exchange filter (HME filter) is routinely placed in the ventilator tubing to ensure that the inhaled air is warm and humidified. Today, HME filters are used routinely in all ventilator treatments. They are typically replaced once a day and discarded as regular waste after use.

The purpose of this study is to investigate whether HME filters contain proteins and small biological particles from the patient's exhaled air.

Study Overview

• Status: Recruiting
• Conditions: Respiratory Inflammation

• Study Type: Observational
• Enrollment (Estimated): 10

Contacts and Locations

• Study Contact: Name: Inger L Gade, PhD; Phone Number: +45 20843941; Email: inlg@rn.dk

Study Locations

• Denmark
  • Gistrup, Denmark, 9260
    • Recruiting
    • Aalborg University Hospital
    • Contact: Lise T Elkjær; Phone Number: +45 20 84 08 32; Email: lit@rn.dk
    • Sub-Investigator: Bodil S Rasmussen, PhD
    • Sub-Investigator: Javier A Quezada, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The investigators will include adult patients who are scheduled for elective surgery for non-malignant conditions under general anesthesia with invasive mechanical ventilation. The written and oral study information will be provided at the standard preoperative consultation with the anesthesiologist the day before elective surgery.

Description

Inclusion Criteria:

• ≥18 years, able to understand study information in Danish.
• Admitted for elective surgery for non-malignant conditions with either intravenous or inhalation anaesthesia and invasive mechanical ventilation according to standard practice.
• Expected invasive mechanical ventilation > 1 hour.
• Possess legal capacity.
• Informed, signed consent is obtained.

Exclusion Criteria:

• Patients who are transferred to the ICU for continuous invasive mechanical ventilation after end of elective surgery.
• Known chronic lung disease.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Elective surgery patients with expected mechanical ventialtion > 2 hours

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total endogenous protein amount captured in HME filters measured by standard biochemical assays.	Quantification of the total amount of endogenous proteins recovered from heat moisture exchange (HME) filters using Biuret based analysis.	Through study completion, an average of 3 months.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Protein molecular weight and isoelectric point distribution in proteins captured by HME filters.	Distribution and representation of captured proteins according to molecular weight and isoelectric point characteristics determined by proteomic analysis.	Through study completion, an average of 3 months.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Between-subject variation in exhaled breath protein concentration measured by proteomic analysis.	Variation in protein concentration across HME filter samples collected from different participants, measured using protein quantification methods.	Through study completion, an average of 3 months.

Collaborators and Investigators

• Sponsor: Aalborg University Hospital

Publications and helpful links

General Publications

• Gade IL, Bodilsen J, Mariager T, Hertz S, Duerlund LS, Holm CK, Madsen PH, Bennike TB, Honore B. Exhaled breath protein composition in patients hospitalised during the first wave of COVID-19. J Breath Res. 2025 May 16;19(3). doi: 10.1088/1752-7163/add617.
• Gade IL, Riddersholm SJ, Stilling-Vinther T, Brondum RF, Bennike TB, Honore B. A clinical proteomics study of exhaled breath condensate and biomarkers for pulmonary embolism. J Breath Res. 2023 Nov 17;18(1). doi: 10.1088/1752-7163/ad0aaa.
• McNeil JB, Shaver CM, Kerchberger VE, Russell DW, Grove BS, Warren MA, Wickersham NE, Ware LB, McDonald WH, Bastarache JA. Novel Method for Noninvasive Sampling of the Distal Airspace in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2018 Apr 15;197(8):1027-1035. doi: 10.1164/rccm.201707-1474OC.
• Bastarache JA, McNeil JB, Plosa EJ, Sucre JS, Kerchberger VE, Habegger LE, Weddle E, Sullivan B, Meegan JE, Wickersham NE, Shaver CM, Ware LB. Standardization of methods for sampling the distal airspace in mechanically ventilated patients using heat moisture exchange filter fluid. Am J Physiol Lung Cell Mol Physiol. 2021 May 1;320(5):L785-L790. doi: 10.1152/ajplung.00595.2020. Epub 2021 Mar 3.

Study record dates

Study Major Dates

• Study Start (Actual): May 8, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: May 8, 2026
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 27, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: exhaled breath proteomics
• Other Study ID Numbers: F2025-193; N-20250044 (Other Identifier: North Denmark Regional Research Ethics Committee)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: All data analyses will be performed in our institution as only conventional biochemical analyses will be applied. No external collaborators are needed and hence the investigators have no need to share IPD outside the instutution.

Drug and device information, study documents

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