Analysis of Breath Sounds During Surgery (BREATHSOUND)

This study aims to analyze breath sounds during surgery by using electronic stethoscope sensors attached to patients under general anesthesia. The study will evaluate whether breath sound monitoring can provide useful information for respiratory management, assist anesthesiologists in early detection of abnormal breathing events, and support safer perioperative care. A total of 30 adult patients undergoing elective surgery under general anesthesia will be enrolled.

Study Overview

• Status: Recruiting
• Conditions: Respiratory Sounds; General Anesthesia; Intraoperative Monitoring
• Intervention / Treatment: Other: Electronic stethoscope monitoring

Detailed Description

Continuous breath sound monitoring has the potential to provide anesthesiologists with real-time physiological information that is not captured by standard perioperative monitors. During general anesthesia, subtle changes in airflow or airway patency may precede clinically apparent respiratory compromise. Traditional auscultation is intermittent, subjective, and dependent on the operator's experience. Recent advances in electronic stethoscope technology enable continuous, high-fidelity acquisition of breath sound signals, allowing quantitative analysis and automated detection of abnormal respiratory patterns.

In this prospective observational study, adult patients undergoing elective surgery under general anesthesia will have electronic stethoscope sensors placed on the anterior chest wall prior to induction. Breath sound signals will be continuously recorded throughout anesthesia and surgery. Signal acquisition parameters (sampling rate, filtering, and sensor placement) will be standardized across participants. All breath sound recordings will be synchronized with standard intraoperative monitoring data, including respiratory rate, tidal volume, capnography, pulse oximetry, and hemodynamic parameters. The synchronized dataset will allow temporal correlation between acoustic features and clinically documented respiratory events.

Collected signals will undergo post-processing to extract quantitative acoustic features such as amplitude, frequency distribution, airflow-related patterns, and event-associated spectral changes. Episodes suggestive of abnormal respiration-such as diminished breath sounds, irregular airflow patterns, obstruction-like signatures, or apnea-like silent periods-will be identified and compared with clinical observations recorded by anesthesia providers. The study will also evaluate the feasibility of integrating continuous breath sound information into perioperative workflows, including the practicality of sensor placement, stability of recordings during surgical manipulation, and compatibility with existing monitoring systems.

The overall goal of the study is to generate foundational evidence on the technical feasibility and clinical relevance of continuous breath sound monitoring under general anesthesia. Findings from this study may support future development of automated respiratory event detection tools and may contribute to safer perioperative respiratory management.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

• Study Contact: Name: Hui-Hsuan Ke, MD; Phone Number: -886-939-196-809; Email: kehuihsuan0221@gmail.com

Study Locations

• Taiwan
  • Taipei, Taiwan, 11217
    • Recruiting
    • Department of Anesthesiology, Taipei Veterans General Hospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Adult surgical patients (aged 20 years or older) scheduled for elective surgery under general anesthesia at Taipei Veterans General Hospital, Taiwan. Eligible patients are ASA I-III and willing to provide informed consent. Patients with significant respiratory disease or airway abnormalities will be excluded.

Description

Inclusion Criteria:

• Age ≥ 20 years
• American Society of Anesthesiologists (ASA) physical status I-III
• Scheduled for elective surgery under general anesthesia
• Provided written informed consent

Exclusion Criteria:

• History of respiratory disease (e.g., COPD, severe asthma)
• Previous airway surgery or anatomical abnormalities that interfere with breath sound assessment
• Refusal to participate or inability to comply with study procedures

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Observation Group; Patients undergoing elective surgery under general anesthesia with endotracheal intubation. Electronic stethoscope patches will be placed to record and analyze intraoperative breath sounds. Target enrollment: 30 participants.	Other: Electronic stethoscope monitoring; Application of electronic stethoscope patches on the patient's chest during surgery to record breath sounds for subsequent analysis. No therapeutic intervention is given; this is a monitoring/observational tool.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Accuracy of electronic breath sound monitoring during surgery	Assessment will be based on the proportion of intraoperative respiratory events correctly identified by the electronic breath sound monitoring system compared with standard clinical assessment.	During surgery (from induction of anesthesia until emergence)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of respiratory events detected by the device	Number of intraoperative respiratory events (e.g., hypoventilation, airway obstruction, disconnection) identified by the monitoring system.	Intraoperative period.
Correlation between electronic breath sound monitoring and clinical observation	Correlation (r-value) between device output and anesthesiologist-documented respiratory findings.	Intraoperative period.
User feasibility and device performance	Feasibility will be assessed by reporting the proportion of cases in which continuous breath sound monitoring was successfully completed without interruption, including documentation of signal quality issues and workflow interference if present. (No rating scale will be used.)	Immediately after surgery (postoperative evaluation).

Collaborators and Investigators

• Sponsor: Taipei Veterans General Hospital, Taiwan
• Investigators: Principal Investigator: Hui-Hsuan Ke, MD, Taipei Veterans General Hospital, Taiwan

Publications and helpful links

General Publications

• Manecke GR Jr, Dilger JP, Kutner LJ, Poppers PJ. Auscultation revisited: the waveform and spectral characteristics of breath sounds during general anesthesia. Int J Clin Monit Comput. 1997 Nov;14(4):231-40. doi: 10.1007/BF03356568.
• Mansy HA, O'Connor CJ, Balk RA, Sandler RH. Breath sound changes associated with malpositioned endotracheal tubes. Med Biol Eng Comput. 2005 Mar;43(2):206-11. doi: 10.1007/BF02345956.
• Wei TJ, Hsiung PY, Liu JH, Lin TC, Kuo FT, Wu CY. Use of Electronic Auscultation in Full Personal Protective Equipment to Detect Ventilation Status in Selective Lung Ventilation: A Randomized Controlled Trial. Front Med (Lausanne). 2022 Feb 21;9:851395. doi: 10.3389/fmed.2022.851395. eCollection 2022.

Helpful Links

• Institutional Review Board of Taipei Veterans General Hospital
• Frontiers in Medicine - Electronic Auscultation Trial

Study record dates

Study Major Dates

• Study Start (Actual): September 3, 2025
• Primary Completion (Estimated): February 28, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: September 17, 2025
• First Submitted That Met QC Criteria: December 9, 2025
• First Posted (Actual): December 12, 2025

Study Record Updates

• Last Update Posted (Actual): December 12, 2025
• Last Update Submitted That Met QC Criteria: December 9, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Perioperative care; Respiratory complications; Breath sounds; Airway monitoring; Double-lumen endotracheal tube (DLT)
• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Respiratory Sounds
• Other Study ID Numbers: 2022-09-002AC

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified breath sound recordings and corresponding clinical parameters (e.g., age, ASA physical status, type of anesthesia) will be shared.
• IPD Sharing Time Frame: Data will be available starting 6 months after study completion and for up to 5 years.
• IPD Sharing Access Criteria: Qualified researchers who provide a methodologically sound research proposal and obtain approval from an independent ethics committee/IRB may request access to de-identified individual participant data (IPD). Requests should be directed to the Institutional Review Board (IRB) of Taipei Veterans General Hospital, Taiwan. Data will be shared through secure platforms to ensure confidentiality and compliance with ethical regulations.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Study Data/Documents

1. Study Protocol
   Information comments: The study protocol describing the methodology of electronic auscultation of breath sounds during anesthesia will be available. De-identified respiratory sound data and related analysis scripts may be shared upon reasonable request to the principal investigator.

Drug and device information, study documents

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