HFLVV for Hypoxemia in Robot-assisted Cardiac Surgery

Army Medical University of People's Liberation Army

Status: Unknown

Conditions: Hypoxemia

Treatments: Procedure: Differential ventilation to the non-dependent lung

Study type: Interventional

Funder types: Other

Identifiers

NCT04926649

2021-59

Details and patient eligibility

About

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.

Enrollment: 56 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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56 participants in 3 patient groups

Conventional ventilation group

Sham Comparator group

Description:

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.

Treatment:

Procedure: Differential ventilation to the non-dependent lung

CPAP group

Active Comparator group

Description:

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.

Treatment:

Procedure: Differential ventilation to the non-dependent lung

HFLVV group

Experimental group

Description:

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.

Treatment:

Procedure: Differential ventilation to the non-dependent lung