Comparison of Three Modes of Ventilation During Robot-assisted Hysterectomy in Trendelenburg Position

Comparison of Three Modes of Ventilation During Robot-assisted Hysterectomy in Trendelenburg Position: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation With Volume Guarantee.

Robot-assisted hysterectomy is associated with pneumoperioneum with CO2 and Trendelenburg position, which may have adverse cardiopulmonary effects. A new ventilation mode; pressure-controlled ventilation with volume guaranteed mode (PCV-VG) delivers constant tidal volume with constant inspiratory pressure, using a decelerating flow pattern. This prospective, randomized study is designed to compare the effects of PCV-VG, volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) on respiratory and hemodynamic variables in patients undergoing Robot-assisted hysterectomy.

1. Total 60 patients with American Society of Anesthesiologists physical status I-II who underwent Robot-assisted hysterectomy were enrolled.
2. All patients were fasted for 8 hours before the surgery and were premedicated with intramuscular glycopyrrolate 0.2 mg. Anesthesia was induced with intravenous remifentanil (0.1-0.2 ug/kg/min), propofol (1.5-2 mg/kg) and rocuronium (0.6 mg/kg) and maintained with sevoflurane (2.0-2.5 vol%) in inspired oxygen fraction with 0.5, remifentanil (0.05-0.3 ug/kg/min) and vecuronium (0.03-0.05 mg/kg/hr).
3. A 20 G catheter was inserted into the radial artery to monitor continuous arterial pressure and hemodynamic variables (cardiac output, cardiac index, stroke volume, stroke volume index, and stroke volume variation) monitoring.
4. All patients were ventilated with a Datex-Ohmeda Ventilator (S/5 AVANCE). Patients were randomized to receive VCV (n=20), PCV (n=20), or PCV-VG (n=20) mode. The tidal volume was set to deliver 8 mL/kg of ideal body weight. The respiratory rate(RR) was adjust to maintain end tidal CO2 (ETCO2) 32-37 mmHg.
5. Hemodynamic variables (mean blood pressure, heart rate, cardiac output, cardiac index, stroke volume, stroke volume index, and stroke volume variation) , respiratory variables (saturation, RR, ETCO2, peak airway pressure, mean airway pressure and lung dynamic compliance) and arterial gas analyses were recorded at 4 stages: (1) 15 minutes after induction in supine position, (2) 30 minutes after pneumoperitoneum and Trendelenburg position, (3) 60 minutes after pneumoperitoneum and Trendelenburg position, (4) 15 minutes after pneumoperitoneum withdrawal in supine position.

Inclusion Criteria:

• Patients who were scheduled for Robot-assisted hysterectomy
• American Society of Anesthesiologists physical status I-II

Exclusion Criteria:

• Age under 20 years old or over 65 years old
• Body mass index > 30 kg/m2
• Systolic blood pressure < 100 mmHg
• Heart rate < 60 bpm
• Uncompensated cardiac disease
• FEV1 < 60%
• Hypoxemia (PaO2 < 60 mmHg or oxygen saturation < 90%)