Related Experiment Video
Updated: Jan 31, 2026

High-precision Electromagnetic Flowmeter with Empty Pipe Detection via Complex Programmable Logic Device-based Waveform Recognition
Published on: June 27, 2025
Broken inspiratory valve detected by capnographic waveforms during general anesthesia: A case report
Mi Young Kim1, Eun Joo Kim1, Ji Hyang Lee1
1Department of Anesthesiology and Pain Medicine, Daegu Fatima Hospital, Daegu, Korea. kej1127@fatima.or.kr.
Abstract:
Unidirectional valve malfunction causes re-breathing of expired gas during anesthesia. Capnography is a useful method for monitoring the integrity of anesthetic equipment such as the unidirectional valves in a circular system. We report, here a case in which the capnography did not sound any rebreathing alarm, but the capnogram showed a prolonged plateau, an apparently short inspiratory period and a gradually sloping descending limb that stopped just short of baseline. As a result, capnography helped to identify an inspiratory unidirectional valve malfunction during the course of anesthesia. This study emphasizes the need to analyze the capnogram during every procedure involving anesthesia, in addition to preoperative checking of the Unidirectional valve.
Related Concept Videos
Effective Value of a Periodic Waveform
The effective value of a periodic current represents the direct current (DC) that conveys the same average power to a resistor as the periodic current itself. This concept is crucial when assessing AC circuits. To determine the...
General Anesthesia: Overview
General anesthesia induces unconsciousness in the whole body, while the others target specific areas or sensations. It is administered to minimize adverse effects, maintain...
Stages of General Anesthesia
Heart Valves
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...
Data Reporting and Recording
Types of Reports I: Hands-off Report
Following are the key components and categories of hand-off reports:
Purpose and Process:

