Waste Anesthetic Gase: A Forgotten Problems

Waste anesthetic gas (WAG) is a small amount of inhaled anesthetic gas that comes out of the patient’s anesthesia breathing circuit into the envorinment air while the patient is under anesthesia. According to American Occupation Safety and HealthAdministration (OSHA) more than 200.000 healthcare workers especially aneaesthesiologist, surgery nurse, obstetrician and surgeons are at risk of developing work-related disease due to chronic exposure to WAG. Exposure to WAG in short time associated with multiple problems such as headaches, irritability, fatigue, nausea, drowsiness, decrease work efficiency and difficulty with judgment and coordination. While chronic exposure of WAG is associated with genotoxicity, mutagenicity, oxidative stress, fatigue, headache, irritability, nausea, nephrotoxic, neurotoxic, hepatotoxic, immunosuppressive and reproductive toxicological effect. Waste anesthetic gases are known as environmental pollutants and will be released from the OR to the outside environment then the substance will reach the atmosphere damaging ozone layer. Exposure to trace WAG in the perioperative environment cannot be eliminated completely,but it can be controlled. Controlling WAG can be achieve by using scavenging system, proper ventilation, airway management, ideal anesthetic choice, maintaining anesthesia machine and equipment, hospital regulation and routine healthcare workers health status examination.

Quality Fade in Medical Device Manufacturing: Thinness of Airway Breathing Circuit Plastic

Mechanical respirators typically use a plastic circuit apparatus to pass gases from the ventilator to the patient. Structural integrity of these circuits is crucial for maintaining oxygenation. Anesthesiologists, respiratory therapists, and other critical care professionals rely on the circuit to be free of defects. The American Society for Testing and Materials maintains standards of medical devices and had a standard (titled Standard Specification for Anesthesia Breathing Tubes) that included circuits. This standard, which was last updated in 2008, has since been withdrawn. Lack of a defined standard can invite quality fade—the phenomenon whereby manufacturers deliberately but surreptitiously reduce material quality to widen profit margins. With plastics, this is often in the form of thinner material. A minimum thickness delineated in the breathing circuit standard would help ensure product quality, maintain tolerance to mechanical insults, and avert leaks. Our impression is that over the recent years, the plastic in many of the commercially available breathing circuits has gotten thinner. We experienced a circuit leak in the middle of a laminectomy due to compromised plastic tubing in a location that evaded the safety circuit leak check that is performed prior to surgery. This compromised ventilation and oxygenation in the middle of a surgery in which the patient is positioned prone and hence with a minimally accessible airway; it could have resulted in anoxic brain injury or death. The incident led us to reflect on the degree of thinness of the circuit's plastic.

Hyperventilation of the lungs as a preventive measure against pneumonia

Based on the works of Corullos and Birnbaum, Scott and Cutler that postoperative pneumonia develops in atelectasized areas of the lungs, Henderson (A. M. A. 1929, 9 II) recommends inhalation of carbon dioxide in oxygen (5,0-100,0), as the most effective means of preventing pneumonia both in postoperative cases and in asphyxia and infectious diseases. As a result of anesthesia, breathing becomes shallow, the sections of the lungs are not ventilated and atelectasis appears, and the infection of these sections easily causes pneumonia; stretching these unventilated collapsed areas by deep breathing as a result of inhalation of carbon dioxide prevents atelectasis and prevents the development of pneumonia.

Effects of the reservoir bag disconnection on inspired gases during general anesthesia: a simulator-based study

Background Fresh gas decoupling is a feature of the modern anesthesia workstation, where the fresh gas flow (FGF) is diverted into the reservoir bag and is not added to the delivered tidal volume, which thus remains constant. The present study aimed to investigate the entraining of the atmospheric air into the anesthesia breathing circuit in case the reservoir bag was disconnected. Methods We conducted a simulator-based study, where the METI HPS simulator was connected to the anesthesia workstation. The effect of the disconnected reservoir bag was evaluated using oxygen (O2) and air or oxygen and nitrous oxide (N2O) as a carrier gas at different FGF rates. We disconnected the reservoir bag for 10 min during the maintenance phase. We recorded values for inspiratory O2, N2O, and sevoflurane. The time constant of the exponential process was estimated during reservoir bag disconnection. Results The difference of O2, N2O and sevoflurane concentrations, before, during, and after reservoir bag disconnection was statistically significant at 0.5, 1, and 2 L/min of FGF (p < 0.001). The largest decrease of the inspired O2 concentrations (FIO2) was detected in the case of oxygen and air as the carrier gas and an FGF of 1 L/min, when oxygen decreased from median [25th–75th percentile] 55.00% [54.00–56.00] to median 39.50% [38.00–42.50] (p < 0.001). The time constant for FIO2 during reservoir bag disconnection in oxygen and air as the carrier gas, were median 2.5, 2.5, and 1.5 min in FGF of 0.5, 1.0, and 2 L/min respectively. Conclusions During the disconnection of the anesthesia reservoir bag, the process of pharmacokinetics takes place faster compared to the wash-in and wash-out pharmacokinetic properties in the circle breathing system. The time constant was affected by the FGF rate, as well as the gradient of anesthetic gases between the anesthesia circle system and atmospheric air.

Effects of a Heated Anesthesia Breathing Circuit on Body Temperature in Anesthetized Rhesus Macaques (Macaca mulatta)

This study evaluated the effects of using a heated anesthesia breathing circuit in addition to forced-air warming on bodytemperature in anesthetized rhesus macaques as compared with forced-air warming alone. Hypothermia is a common perianestheticand intraoperative complication that can increase the risk of negative outcomes. Body heat is lost through 4 mechanisms during anesthesia: radiation, conduction, convection, and evaporation. Typical warming methods such as forced-air warming devices, conductive heating pads, and heated surgical tables only influence radiative and conductive mechanisms of heatloss. A commercially available heated breathing circuit that delivers gas warmed to 104 °F can easily be integrated into ananesthesia machine. We hypothesized that heating the inspired anesthetic gas to address the evaporative mechanism of heatloss would result in higher body temperature during anesthesia in rhesus macaques. Body temperatures were measured at 5-min intervals in a group of 10 adult male rhesus macaques during 2 anesthetic events: one with a heated anesthesia breathing circuit in addition to forced-air warming, and one with forced-air warming alone. The addition of a heated breathing circuit had a significant positive effect on perianesthetic body temperature, with a faster return to baseline temperature, earlier nadir of initial drop in body temperature, and higher body temperatures during a 2-h anesthetic procedure. Use of a heated anesthesia breathing circuit should be considered as a significant refinement to thermal support during macaque anesthesia, especially for procedures lasting longer than one hour.

Waste Anesthetic Gase : A Forgotten Problems

ABSTRACT Waste anesthetic gas (WAG) is a small amount of inhaled anesthetic gas that comes out of the patient’s anesthesia breathing circuit into the envorinment air while the patient is under anesthesia. According to American Occupation Safety and Health Administration (OSHA) more than 200.000 healthcare workers especially aneaesthesiologist, surgery nurse, obstetrician and surgeons are at risk of developing work-related disease due to chronic exposure to WAG. Exposure to WAG in short time associated with multiple problems such as headaches, irritability, fatigue, nausea, drowsiness, decrease work efficiency and difficulty with judgment and coordination. While chronic exposure of WAG is associated with genotoxicity, mutagenicity, oxidative stress, fatigue, headache, irritability, nausea, nephrotoxic, neurotoxic, hepatotoxic, immunosuppressive and reproductive toxicological effect. Waste anesthetic gases are known as environmental pollutants and will be released from the OR to the outside environment then the substance will reach the atmosphere damaging ozone layer. Exposure to trace WAG in the perioperative environment cannot be eliminated completely, but it can be controlled. Controlling WAG can be achieve by using scavenging system, proper ventilation, airway management, ideal anesthetic choice, maintaining anesthesia machine and equipment, hospital regulation and routine healthcare workers health status examination.

Removal of an Airway Foreign Body via Flexible Endoscopy Through a Laryngeal Mask Airway

A Silky terrier weighing 4.7 kg was presented with an airway foreign body after having aspirated a fragment of an orotracheal tube that was identified on radiological examination. Due to the small size of the patient, flexible endoscopy could not be performed through the lumen of a tracheal tube. Following IV induction of general anesthesia, the airway was instrumented with a laryngeal mask airway that was attached via a three-way connector to an anesthesia breathing circuit. A flexible endoscope was passed through the free port of the connector. That arrangement allowed for the passage of an endoscope through the lumen of the laryngeal mask airway and into the trachea without interrupting the continuous supply of O2 and sevoflurane.