Safety in Anaesthesia Waste Anaesthetic Gases (WAG) PDF

SAFETY IN ANAESTHESIA NSCI5711 Veterinary WASTE ANAESTHETIC Anaesthetic and Surgical GASES (WAG) Procedures  LEARNING OBJECTIVES Understand the risks involved in anaesthetising a patient Understand how to mitiga...

SAFETY IN ANAESTHESIA NSCI5711 Veterinary WASTE ANAESTHETIC Anaesthetic and Surgical GASES (WAG) Procedures  LEARNING OBJECTIVES Understand the risks involved in anaesthetising a patient Understand how to mitigate these risks in order keep yourself and others safe during anaesthetic procedures Know where to find your rights and legislation regarding safe practice  COMMON ANAESTHETIC GASES  Volatile halogenated agents: - Isoflurane – most common anaesthetic agent in veterinar y practice, clear, colourless liquid at room temperature. - Desflurane - Sevoflurane  Non-volatile agents: - Nitrous Oxide – inhaled gas, anaesthetic and analgesic proper ties, used alongside oxygen and isoflurane sometimes  Any others? Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  ANAESTHETIC RISK Waste anaesthetic gases (WAG) – mainly isoflurane - occur as the patient breathes out during and after anaesthesia Chronic (long-term) exposure to trace amounts of WAGs in the environment should be avoided.  WHY??  “Studies conducted over the last centur y have suggested that chronic exposure to trace levels of inhalational anaesthetic agents may constitute a human health hazard.  Low levels of anaesthetic agents such as isoflurane will accumulate in work areas where poor anaesthetic standards are practised e.g. failure to scavenge waste gases from the pop-of f valve and failure to recognize and repair leaking anaesthetic breathing circuits.  A possible association between chronic exposure to inhalational agents and a number of adverse ef fects has been demonstrated in a variety of human health professionals. These disorders included neurological ef fects, reproductive abnormalities, cancer and an increased incidence of liver and kidney disease compared to people not exposed to these agents.” h tt ps : / / mo o d l e.u n i te c. ac.n z / p l u gi n f i l e. p h p/ 4 8 5 9 9 9 / mo d _ b o ok / c h a pter / 4 6 5 8 4 / I n h a l a t i on al % 2 0 A n a es th et i c % 2 0 A ge n ts %2 0 an d % 2 0H u m an % 2 0 S a f et y. pd f  ANAESTHETIC GAS RISKS Where and when are the risks of exposure?  Isoflurane bottle  Filling the vaporizer  Connections and piping  Anaesthetic circuits  E.T tubes  Scavenging system  Gas masks…  Patients exhaled breath  Human error!  REDUCING EXPOSURE TO ANAESTHETIC GASES Minimizing exposure to anaesthetic gases involves: Practicing good anaesthetic technique Ensuring all staff are properly trained Equipment is available, used correctly and is properly cared for  HOW CAN WE REDUCE EXPOSURE?  E.T tube – cuffed - correct size – single-use!?  Turn gas on AFTER connecting to patient and inflating cuff  Turn gas off BEFORE disconnecting patient  Flush circuits with O2 after use  Using an appropriate scavenging system  Well-ventilated rooms - controlling temp, humidity, air movement  Recover on o2 for as long as possible (patients expire large volumes of anaesthetic agents during this time).  Keep face away from patients in recover y  Careful, regular maintenance of the equipment  Per forming pressure checks of the high and low-pressure systems  Filling the vaporiser in a well-ventilated area and taking great care to prevent spills. Using agent-specific filling devices if available.  Avoiding or minimising the number of times the patient is disconnected from the circuit Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  MACHINE MAINTENANCE Anaesthesia machines, ventilators, breathing systems, and waste-gas scavenging systems may contribute to environmental pollution with waste anaesthetic gases. Appropriate inspection for proper functioning and routine maintenance for such equipment should be standard operating procedures for veterinary facilities. Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  CHECK YOUR CIRCUITS! Keep well maintained circuits: Proper use and function Checked prior to every patient – circuit check Cleaned regularly – or even replaced!! Check connections, valves, tubing, rebreathing bags… (plastic/rubber can perish!) “91 % of the anaesthetic machines tested had faults or leaks which would result in pollution of the working environment” (Machon, 1999)  FILLING THE VAPORIZER Photo source: http://www.howequipmentworks.com/physics/agent_delivery/vaporizer/vaporizers.html = vaporuiser When filling the vaporiser.  Ensure the area is well ventilated.  Minimise the number of people present and rotate staff  Use the correct filling attachments ‘Isoflurane Key’. Do not overfill and be very careful not to spill the liquid. Check your clinic’s policy for managing a spill should it occur. https://www.youtube.com/watch?v=eu 6FvOzAFpQ https://www.youtube.com/watch?v=LB FILLING A Zhd_ApHRo VAPORISER https://www.youtube.com/watch?v=oS iFpnuUZBs  ENDOTRACHEAL TUBES  Use cuffed endotracheal (ET) tubes (that are the correct size for the animal!) Lish, J., Ko, J. C., & Payton, M. E. (2008). Evaluation of Two Methods of Endotracheal Tube Selection in Dogs. Journal of the American Animal Hospital Association, 44(5), 236-242. doi:10.5326/0440236  Ensure all ET tubes are in good condition  Cuffed ET tubes (check for damage after each use)  Single use ET tubes?  Remember the LISTEN FOR A LEAK test when inflating.  Don’t deflate the cuff too early  CORRECT ET TUBE MEASUREMENTS https://goo.gl/images/hNXqwB https://www.vetmed.wisc.edu/wp-content/uploads/2013/01/Anesthesia_Cheat_Sheet.pdf  WAG SCAVENGING SYSTEMS  Passive scavenging vs. active scavenging of WAG??  BEST PRACTICE is active WAG scavenging, with gentle suction of gases away from the breathing circuit – piped into the building.  MANY clinics in NZ still using passive scavenging (62.7%) – tube out of the window? Into a canister? (Prior, 2023).  RECOVERY PERIOD Patients expire anaesthetic agents during the recovery period.  At the end of the procedure allow the patient to recover for as long as possible connected to the anaesthetic machine (on O 2 only).  Have well ventilated recovery rooms.  Do not position your face close to a recovering patient.  ‘MASKING’ AN ANIMAL DOWN  Inducing a patient using a mask or chamber involves greater risk of staff exposure to anaesthetic gases.  AVOID where possible – there are safer options  If it is unavoidable:  Use correct mask size with a seal.  Well ventilated area (and use exhaust fans if present).  Avoid unnecessarily high O 2 flow rates when masking down patients.  Connect induction chambers to scavenging systems. Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  ANAESTHETIC SAFETY WHILST PREGNANT “Occupational exposure to inhalant anaesthetic gases has often been linked with health hazards and reproductive toxicity in health care personnel. However, scientific evidence for a causal relationship between exposure to trace concentrations of waste anaesthetic gases and reproductive effects… appears to be unclear.” HEALTH AND SAFET Y DURING PREGNANCY AND LACTATION, NZVNA, 2007  ANAESTHETIC SAFETY WHILST PREGNANT “Although the proposed negative health effects of modern- day halogenated agents, such as isoflurane and sevoflurane, may not be based on definitive evidence, most in the field favour erring on the side of caution regarding WAG exposure management and safety protocols (Tankó et al., 2014; Fay, 2018).” Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  ANAESTHETIC SAFETY WHILST PREGNANT SO… better to be safe. If you are pregnant, speak to your healthcare provider and consider avoiding:  Filling the vaporiser  Induction/Extubation  Initially recovering patients  Monitoring anaesthesia when animals are being moved around a lot/transferred/disconnected and reconnected.  Masking a patient ‘down’  Basically, everything we just spoke about….  PREGNANCY AND ANAESTHESIA  Some useful resources around pregnancy and anaesthesia  https://www.nzvna.org.nz/site/nzvna/files/ar ticles//_Safety_During_Pregnancy___Lactat ion_22Jun07.pdf  https://www.nzvna.org.nz/site/nzvna/files/Documents/Veterinar y%20Nursing%20during %20Pregnancy.pdf  Shirangi, A., Fritschi, L. and Holman, C. (2008) ‘Maternal occupational exposures and risk of spontaneous abortion in veterinary practice’, Australian Veterinary Journal, 65(11), pp. 719-725. Available at: https://doi.org /10.1136/oem.2007.035246.  Allweiler, S.I. and Kogan, L.R. (2013) ‘Inhalation anesthetics and the reproductive risk associated with occupational exposure among women working in veterinary anesthesia’, Veterinary Anaesthesia and Analgesia, 40(3), pp. 285–289. Available at: https://doi.org /10.1111/VAA.12014  MONITORING EXPOSURE A ‘passive diffusion monitor’ can be used to monitor the substance exposure if there is uncertainty about the levels of exposure. Available from most major safety equipment suppliers. The various types of passive monitoring badges are:  Organic vapour monitor, which monitors for halothane and isoflurane;  Formaldehyde monitor  Ethylene oxide monitor When monitoring is undertaken, the employee must receive a copy of the report. Prior, L. (2023) Exposure to Waste Anaesthetic Gases (WAGs) in New Zealand Veterinary Practices: Mitigation Protocols and Levels of Staff Awareness. [Master’s Dissertation], The University of Edinburgh, Royal (Dick) School of Veterinary Studies.  GUIDELINES FOR NURSES IN PRACTICE Health and Safety act 2015 - https://www.employment.govt.nz/workplace- policies/health-and-safety-at-work/ Anaesthetic Gases: Guidelines for Workplace Exposures - https://www.osha.gov/dts/osta/anestheticgases/ Anaesthetic Gas Guidelines – University of Iowa - https://ehs.research.uiowa.edu/isoflurane-anesthetic-gas-guidelines Health and Safety Authority (HSA) (Ireland) (2014) Controlling Waste Anaesthetic Gases in Healthcare Settings, https://www.hsa.ie/eng/Publications_and_Forms/Publications/Healthcare _Sector/Waste_Anaesthetic_Gases_Information_Sheet.pdf  CONCLUSIONS FROM MY RESEARCH:  An alarming number of NZ veterinary employees have experienced acute symptoms of WAG exposure - 73.2% (n=112)  Over half (66%, n=101) of respondents stated that the anaesthetic machines in their clinics were serviced at least once per year.  More than half (62.7%, n=73) of respondents reported that WAGs were passively scavenged without suction.  Passive diffusion monitors for WAGs were only used in 1.3% (n=2) of respondents’ clinics.  Almost all respondents (96.73%, n=148) indicated they were unaware of any existing SPECIFIC legislation or safe practising guidelines surrounding WAG management in NZ – this is because there isn’t any! QUESTIONS? CONCERNS?