HFLVV for Hypoxemia in Robot-assisted Cardiac Surgery

The High-frequency Low-volume Ventilation (HFLVV) for Hypoxemia During the Weaning From Cardiopulmonary Bypass in Robot-assisted Cardiac Surgery

These robot-assisted cardiac surgeries usually require single-lung ventilation (SLV) to facilitate surgical exposure. SLV creates ventilation/perfusion mismatch and shunt (Qs:Qt) through the collapsed lung and leads to hypoxemia. Pulmonary gas exchange often deteriorates after cardiopulmonary bypass (CPB) because of ischemic tissue damage. In some cases, severe hypoxemia may require the cessation of surgical procedures and the initiation of double-lung ventilation to improve oxygenation. In this study, the investigator applied the continuous positive airway pressure (CPAP) or the high-frequency low-volume ventilation (HFLVV) to the non-dependent lung (differential ventilation) during the weaning from CPB. The investigator hypothesized that the differential ventilation would produce the least interference with the surgeon's exposure and better oxygenation. The investigators evaluate the airway pressure, shunt fraction, PaO2/FiO2, cerebral oximetry, surgical field condition and the length of stay in intensive care unit of patients underwent the robot-assisted cardiac surgery.

Study Overview

• Status: Enrolling by invitation
• Conditions: Hypoxemia
• Intervention / Treatment: Procedure: Differential ventilation to the non-dependent lung

• Study Type: Interventional
• Enrollment (Anticipated): 56
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Chongqing
    • Chongqing, Chongqing, China, 400042
      • Daping Hospital, Army Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• scheduled for robot-assisted cardiac surgery with cardiopulmonary bypass

Exclusion Criteria:

• age <18 or > 70 years
• PaO2/FiO2 ratio < 300 mmHg before anesthesia induction
• American Society of Anesthesiologist (ASA) Grade > 3
• Patients who were converted to conventional open-chest procedure

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: Conventional ventilation group; Conventional SLV and complementary with DLV when necessary. When SLV was initiated, the patient was ventilated with left lung. FiO2 of 1.0, tidal volume of 6ml/kg, respiratory rate of 16-24 bpm, PEEP of 5-10 cmH2O. The right lung was totally collapsed. If the SpO2 decreased lower than 90%, DLV was started and the operation was paused until the SpO2 increased to 100%. Then the operation was restarted.	Procedure: Differential ventilation to the non-dependent lung; When the hypoxemia occurs during sing lung ventilation in robot-assisted cardiac surgery, the non-dependent lung will be ventilated with normal tidal volume in conventional ways and the surgery procedure have to be ceased. In this trial, the non-dependent lung will be ventilated with the continuous positive airway pressure (CPAP) or the high-frequency low-volume ventilation (HFLVV) to prevent the hypoxemia.
Active Comparator: CPAP group; SLV of left lung and CPAP of right lung, and complementary with DLV when necessary. When SLV was initiated, the patient was ventilated with left lung. FiO2 of 1.0, tidal volume of 6ml/kg, respiratory rate of 16-24 bpm, PEEP of 5-10 cmH2O. After the right lung was totally collapsed, CPAP was started with the pressure less than 8 cmH2O. If SpO2 decreased lower than 90%, DLV was started and the operation was paused until the SpO2 increased to 100%. Then the operation was restarted.	Procedure: Differential ventilation to the non-dependent lung; When the hypoxemia occurs during sing lung ventilation in robot-assisted cardiac surgery, the non-dependent lung will be ventilated with normal tidal volume in conventional ways and the surgery procedure have to be ceased. In this trial, the non-dependent lung will be ventilated with the continuous positive airway pressure (CPAP) or the high-frequency low-volume ventilation (HFLVV) to prevent the hypoxemia.
Experimental: HFLVV group; SLV of left lung and HFLVV of right lung, and complementary with DLV when necessary. When SLV was initiated, the patient was ventilated with left lung. FiO2 of 1.0, tidal volume of 6ml/kg, respiratory rate of 16-24 bpm, PEEP of 5-10 cmH2O. After the right lung was totally collapsed, HFLVV was started with tidal volume of 2ml/kg, respiratory rate of 60 bpm. If SpO2 decreased lower than 90%, DLV was started and the operation was paused until the SpO2 increased to 100%. Then the operation was restarted.	Procedure: Differential ventilation to the non-dependent lung; When the hypoxemia occurs during sing lung ventilation in robot-assisted cardiac surgery, the non-dependent lung will be ventilated with normal tidal volume in conventional ways and the surgery procedure have to be ceased. In this trial, the non-dependent lung will be ventilated with the continuous positive airway pressure (CPAP) or the high-frequency low-volume ventilation (HFLVV) to prevent the hypoxemia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of arterial PaO2	Arterial PaO2 (in mmHg) defined as a measurement of partial pressure of oxygen in arterial blood	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of PaO2/FiO2 ratio	PaO2/FiO2 ratio defined as the ratio of PaO2 to fractional inspired oxygen (FiO2 expressed as a fraction)	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of Heart rate	Heart rate in beat per minute	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV
Changes of mean blood pressure	mean blood pressure in mmHg	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of cardiac stroke volume variation	Cardiac stroke volume variation in percentages	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of venous pressure of jugular vein	Venous pressure of jugular vein in cmH2O	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of tidal volume	Tidal volume of both lungs in milliliter	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of respiratory rates	Respiratory rates of both lungs in breath per minute	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of airway pressure	Airway pressure of both lungs in mmHg	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of end-tidal carbon dioxide tension	End-tidal carbon dioxide tension in mmHg	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of blood oxygen saturation	Blood oxygen saturation of both upper and lower extremities in percentages	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of the pulmonary shunt fraction	Qs/Qt = ((CcO2 - CaO2) / (CcO2 - CvO2)) * 100	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of regional cerebral oxygen saturation	regional cerebral oxygen saturation in percentages	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]
Changes of the surgical field	The surgeon's evaluation of the surgical field, graded from 0 (no interference) to 3 (maximal interference)	5 min after induction of anesthesia during DLV, 5 min after SLV, 5 min after HFLVV, 5 min after CPB flow reduced to 1/3, 5min after CPB flow reduced to 2/3, 15min after resuming of DLV]

Collaborators and Investigators

• Sponsor: Daping Hospital and the Research Institute of Surgery of the Third Military Medical University
• Investigators: Principal Investigator: Qingxiang Mao, M.D., Ph.D., Daping Hospital, Army Medical University

Publications and helpful links

General Publications

• Kremer R, Aboud W, Haberfeld O, Armali M, Barak M. Differential lung ventilation for increased oxygenation during one lung ventilation for video assisted lung surgery. J Cardiothorac Surg. 2019 May 6;14(1):89. doi: 10.1186/s13019-019-0910-2.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2021
• Primary Completion (Anticipated): December 15, 2021
• Study Completion (Anticipated): March 15, 2022

Study Registration Dates

• First Submitted: May 31, 2021
• First Submitted That Met QC Criteria: June 10, 2021
• First Posted (Actual): June 15, 2021

Study Record Updates

• Last Update Posted (Actual): June 15, 2021
• Last Update Submitted That Met QC Criteria: June 10, 2021
• Last Verified: June 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Hypoxia
• Other Study ID Numbers: 2021-59

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