Hypoxemia
Conditions
Brief summary
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.
Interventions
PROCEDUREDifferential 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.
Sponsors
Daping Hospital and the Research Institute of Surgery of the Third Military Medical University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes of arterial PaO2 | 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] | Arterial PaO2 (in mmHg) defined as a measurement of partial pressure of oxygen in arterial blood |
| Changes of PaO2/FiO2 ratio | 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] | PaO2/FiO2 ratio defined as the ratio of PaO2 to fractional inspired oxygen (FiO2 expressed as a fraction) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes of cardiac stroke volume variation | 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] | Cardiac stroke volume variation in percentages |
| Changes of venous pressure of jugular vein | 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] | Venous pressure of jugular vein in cmH2O |
| Changes of tidal volume | 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] | Tidal volume of both lungs in milliliter |
| Changes of respiratory rates | 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] | Respiratory rates of both lungs in breath per minute |
| Changes of airway pressure | 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] | Airway pressure of both lungs in mmHg |
| Changes of Heart rate | 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 | Heart rate in beat per minute |
| Changes of blood oxygen saturation | 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] | Blood oxygen saturation of both upper and lower extremities in percentages |
| Changes of the pulmonary shunt 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] | Qs/Qt = ((CcO2 - CaO2) / (CcO2 - CvO2)) \* 100 |
| Changes of regional cerebral oxygen saturation | 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] | regional cerebral oxygen saturation in percentages |
| Changes of the surgical field | 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] | The surgeon's evaluation of the surgical field, graded from 0 (no interference) to 3 (maximal interference) |
| Changes of end-tidal carbon dioxide tension | 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] | End-tidal carbon dioxide tension in mmHg |
| Changes of mean blood pressure | 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] | mean blood pressure in mmHg |
Countries
China
Outcome results
None listed