Comparison of Flow Controlled Ventilation and Volume Controlled Ventilation

Comparison of Flow Controlled Ventilation and Volume Controlled Ventilation in Microscopic Laryngeal Surgeries, a Randomized Controlled Trial

Flow-Controlled Ventilation is designed to ventilate the patient with constant flows during both inspiration and expiration. During inspiration, the pressure rises linearly from a set positive end-expiratory pressure (PEEP) to a set positive inspiratory pressure (PIP), and then falls linearly from PIP to end-expiratory pressure (EEP) during expiration. There are no flow interruptions during the Flow-Controlled Ventilation cycle, and the rate of change of pressure and volume in the lungs is equal, allowing for higher tidal volumes at lower pressures. The user sets the inspiratory flow rate and the ratio of inspiratory to expiratory time, providing full control over the ventilation cycle. However, this results in two unusual features: During inspiration, the ventilator creates positive pressure to direct gas into the patient's lungs through the endotracheal tube (ETT). When the intratracheal pressure (airway pressure) reaches the set PIP value, the ventilator switches from inspiration to expiration. By reversing the flow, it utilizes the Bernoulli effect to create negative pressure, facilitating expiration. Despite the presence of negative pressure on the ventilator side, the pressure in the patient's airway remains positive at all times.

Volume-controlled ventilation is a mode that is volume-controlled, time-cycled, time-triggered, and pressure-limited. In volume-controlled ventilation, high pressures are sometimes necessary to reach the target tidal volume. This can lead to barotrauma, atelectrauma, and volutrauma in the lungs. Therefore, to avoid high pressures, low tidal volume ventilation is preferred.

For Microscopic Laryngeal Surgeries, patients are intubated with a small sized endotracheal tube which results with higher pressures. We think that flow controlled ventilation will improve the ventilation during the surgery with lower pressures.

Study Overview

• Status: Completed
• Conditions: Vocal Cord Cyst; Vocal Cord Disease
• Intervention / Treatment: Procedure: Intubation; Device: Flow Controlled Ventilation; Device: Volume Controlled Ventilation

• Study Type: Interventional
• Enrollment (Actual): 68
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Kocaeli, Turkey (Türkiye), 41350
    • Kocaeli University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients who undergo elective microscopic laser surgery
• ASA status I and II

Exclusion Criteria:

• Surgery time more than 2 hours
• Patients with difficult intubation
• Patients with chronic lung diseases
• BMI > 25

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: FCV Group; Patients who will be ventilated with flow controlled ventilation following the intubation	Procedure: Intubation; Patients will be intubated with 5mm sized endotracheal tube for microscopic laryngeal surgery; Device: Flow Controlled Ventilation; Patients in FCV group will be ventilated with flow controlled ventilation mode
Active Comparator: VCV Group; Patients who will be ventilated with volume controlled ventilation following the intubation	Procedure: Intubation; Patients will be intubated with 5mm sized endotracheal tube for microscopic laryngeal surgery; Device: Volume Controlled Ventilation; Patients in VCV group will be ventilated with volume controlled ventilation mode

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PIP	Peak inspiratory pressure	10 minutes interval after the intubation during the surgery
RR	Respiratory rate	10 minutes interval after the intubation during the surgery
TV	Tidal volume	10 minutes interval after the intubation during the surgery
Compliance (Cdyn)	Dynamic compliance (ventilator calculates: Cdyn = tidal volume/(PIP - PEEP)	10 minutes interval after the intubation during the surgery
Resistance	Resistance (ventilator calculates: dividing the [peak pressure minus the plateau pressure] by the flowrate in litres per second)	10 minutes interval after the intubation during the surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
HR	Heart rate	10 minutes interval after the intubation during the surgery
MP	Mean blood pressure	10 minutes interval after the intubation during the surgery
SpO2	Oxygen saturation	10 minutes interval after the intubation during the surgery

Collaborators and Investigators

• Sponsor: Kocaeli University

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2024
• Primary Completion (Actual): January 15, 2026
• Study Completion (Actual): February 1, 2026

Study Registration Dates

• First Submitted: June 29, 2024
• First Submitted That Met QC Criteria: July 8, 2024
• First Posted (Actual): July 9, 2024

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 25, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Microscopic Laryngeal Surgery; Flow Controlled Ventilation; Volume Controlled Ventilation
• Additional Relevant MeSH Terms: Investigative Techniques; Therapeutics; Intubation
• Other Study ID Numbers: KAEK/05.bI.07

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No