Twenty patients were anesthetized with intermittent intravenous anesthetics and paralyzed with either d-tubercurarine or pancuronium. For the operations for 8 of them (group 1) ventilation was supplied through a 16 G Angiocatch introduced into the trachea through the cricothyroid membrane. For the operations for 12 remaining patients(group 2) ventilation was supplied through a 5 mm endotracheal catheter. A respiratory rate of 100 breaths/minute was used at an FiO₂ 1.0 using a solenoid valve-actuated ventilator. The inspiratory-expiratory ratio was 1:2. The driving pressure of oxygen was 10-45 psi. In neither group was there any significant change in the value of the pH, of PaCO₂, or of PaO₂. Cardiovascular parameters such as blood pressure and heart rate were slightly increased. Data obtained from these observations indicate that these techniques and devices when used properly, should provide adequate ventilation and improve the visibility of the operative field.