Open drop Anesthesia - Traditional method of administering anesthesia

Open Drop Anesthesia -continued use in developing countries although not used in modern medicine -high volatile anesthetic dripped onto a gauze covered mask which is applied to the patient's face -during inspiration: air passes through the gauze and vaporizes the liquid anesthetic into high concentrations of gas to the patient -decreased minute ventilation occurs with deep anesthesia which increases the vapor pressure of the anesthetic agent -increased anesthetic vapor pressure with decreased MV will further lead to deepening anesthesia which can lead to a fatal viscous cycle -significant rebreathing of anesthetic gases is possible if trapped CO2 is present under the mask -hypoxic mixtures may be occur if anesthetic agents dilute the inspired oxygen concentration -to avoid hypoxic mixtures supplemental oxygen may be provided -uncontrollable pollution of anesthetic gases to the operating room may be hazardous especially with flammable agents Disadvantages of Insufflation and open drop anesthesia -poor control of inspired gas concentrations -inability to assist or control ventilation -no conservation of heat or humidity -difficult airway management especially during head and neck procedures -pollution of large volumes of waste gas into the operating room