The Anesthesia Gas Machine

Michael P. Dosch CRNA PhD
University of Detroit Mercy Graduate Program in Nurse Anesthesiology
This site is http://www.udmercy.edu/crna/agm/.

Revised July 2012

ANESTHESIA GAS MACHINE> COMPONENTS & SYSTEMS> PUTTING IT ALL TOGETHER: MACHINE CHECKLIST, MEDICOLEGAL, CLEANING & STERILIZATION

Putting it all together: Machine checklist, Medicolegal, Cleaning & sterilization

Anesthesia gas machine check

"Apparatus of reliable appearance engenders a strong feeling of security which is often not supported by facts. A critical attitude often forestalls unpleasant surprises." Lucien Morris, in Aldrete Lowe & Virtue Low Flow & Closed System Anesthesia Grune & Stratton 1979.

"One of the things I notice about the practice of anesthesia is the extensive use of protocols and procedures. As I learn more about anesthesia I realize how important protocols and procedures are to increase patient safety. As a lawyer I also see that these procedures can protect the anesthetist. Should the anesthetist be required to defend himself or herself, it may be difficult to remember the exact details of an anesthetic given years before. Sometimes, it is helpful to be able to testify that certain matters are always done by following careful procedures, even if you cannot remember what happened in a particular case. Giving an anesthetic clearly requires thought and judgment, but the importance of having and following procedures can not be minimized. If you begin your day or each operation checking out your anesthesia machine according to FDA guidelines, then even if you cannot remember what you did on February 1, 1995, you will know you checked the anesthesia machine because that is what you always do." Gene Blumenreich AANA Journal 2000;68:107-10.

Pre-Anesthesia Checklist (PAC) 2008

Prior to the late 1980s, gas machine operator's manuals contained preoperative checks for each model. These were exhaustive, reflecting an engineer's perspective, not a clinician's.

A checklist usable for all gas machines was proposed by the professions and accepted by the FDA in 1987 (and revised in 1993). The 1993 checklist has been relatively well-studied. It has been found that users did not use the checklist consistently, and that it was not completely effective in discovering faults. Further, modern gas machines with sophisticated electronic controls have automated checkout routines built in.

The 1993 FDA checklist has been superseded by the latest revision (2008). The PAC 2008 is principles-based, since no one procedural checklist applies to all modern gas machine models. Therefore, it is envisioned that each department will prepare a procedure list which is appropriate for checkout of each type of gas machine they use.

Importance of the gas machine checklist

As recently as May 2000 (Health Devices 2000;29:188-9) it was reported that failure to check a disposable breathing circuit led to a patient fatality. Studies have shown the need for providers to improve their skills at checking gas machines with known faults (or perhaps the need for improved equipment)- see AANA Journal 2000;68:497-505, and AANA Journal 1996;64:277-82. The Closed Claims study of gas delivery equipment (Anesthesiology 1997;87:741-8) concluded that misuse of equipment was three times more prevalent than equipment failure, and that educational and preventive strategies were needed.
Pre-Anesthesia Checklist 2008
Step
Rationale
  1. Verify auxiliary oxygen cylinder and self-inflating manual ventilation device are available & functioning
Failure to be able to ventilate is a major cause of morbidity and mortality related to anesthesia care. Because equipment failure with resulting inability to ventilate the patient can occur at any time, a self-inflating manual ventilation device (eg. AMBU bag) should be present at every anesthetizing location for every case and should be checked for proper function. In addition, a source of oxygen separate from the anesthesia machine and pipeline supply, specifically an oxygen cylinder with regulator and a means to open the cylinder valve, should be immediately available and checked. After checking the cylinder pressure, it is recommended that the main cylinder valve be closed to avoid inadvertent emptying of the cylinder through a leaky or open regulator.
  1. Verify patient suction is adequate to clear the airway
Safe anesthetic care requires the immediate availability of suction to clear the airway if needed.
  1. Turn on anesthesia delivery system and confirm that AC power is available.
Anesthesia delivery systems typically function with backup battery power if AC power fails. Unless the presence of AC power is confirmed, the first obvious sign of power failure can be a complete system shutdown when the batteries can no longer power the system. Many anesthesia delivery systems have visual indicators of the power source showing the presence of both AC and battery power. These indicators should be checked and connection of the power cord to a functional AC power source should be confirmed.
Desflurane vaporizers require electrical power and recommendations for checking power to these vaporizers should also be followed.
  1. Verify availability of required monitors and check alarms.

Standards for patient monitoring during anesthesia are clearly defined. The ability to conform to these standards should be confirmed for every anesthetic.

  • The first step is to visually verify that the appropriate monitoring supplies (BP cuffs, oximetry probes, etc.) are available. All monitors should be turned on and proper completion of power-up self tests confirmed.
  • Given the importance of pulse oximetry and capnography to patient safety, verifying proper function of these devices before anesthetizing the patient is essential.
    • Capnometer function can be verified by exhaling through the breathing circuit or gas sensor to generate a capnogram, or verifying that the patient’s breathing efforts generate a capnogram before the patient is anesthetized. Visual and audible alarm signals should be generated when this is discontinued.
    • Pulse oximeter function, including an audible alarm, can be verified by placing the sensor on a finger and observing for a proper recording. The pulse oximeter alarm can be tested by introducing motion artifact or removing the sensor.
  • Audible alarms have also been reconfirmed as essential to patient safety by ASA, AANA, APSF and JCAHO. Proper monitor functioning includes visual and audible alarm signals that function as designed.
  1. Verify that pressure is adequate on the spare oxygen cylinder mounted on the anesthesia machine.

Anesthesia delivery systems rely on a supply of oxygen for various machine functions. At a minimum, the oxygen supply is used to provide oxygen to the patient. Pneumatically-powered ventilators also rely on a gas supply.

Oxygen cylinder(s) should be mounted on the anesthesia delivery system and determined to have an acceptable minimum pressure. The acceptable pressure depends on the intended use, the design of the anesthesia delivery system and the availability of piped oxygen. Typically, an oxygen cylinder will be used if the central oxygen supply fails.

  • If the cylinder is intended to be the primary source of oxygen (e.g. remote site anesthesia), then a cylinder supply sufficient to last for the entire anesthetic is required.
  • If a pneumatically-powered ventilator that uses oxygen as its driving gas will be used, a full “E” oxygen cylinder may provide only 30 minutes of oxygen. In that case, the maximum duration of oxygen supply can be obtained from an oxygen cylinder if it is used only to provide fresh gas to the patient in conjunction with manual or spontaneous ventilation. Mechanical ventilators will consume the oxygen supply if pneumatically powered ventilators that require oxygen to power the ventilator are used.
  • Electrically-powered ventilators do not consume oxygen so that the duration of a cylinder supply will depend only on total fresh gas flow.

The oxygen cylinder valve should be closed after it has been verified that adequate pressure is present, unless the cylinder is to be the primary source of oxygen (i.e. piped oxygen is not available). If the valve remains open and the pipeline supply should fail, the oxygen cylinder can become depleted while the anesthesia provider is unaware of the oxygen supply problem.

Other gas supply cylinders (e.g. Heliox, CO2, Air, N2O) need to be checked only if that gas is required to provide anesthetic care.

  1. Verify that piped gas pressures are ≥ 50 psig.
A minimum gas supply pressure is required for proper function of the anesthesia delivery system. Gas supplied from a central source can fail for a variety of reasons. Therefore the pressure in the piped gas supply should be checked at least once daily.
  1. Verify that vaporizers are adequately filled and, if applicable, that the filler ports are tightly closed.

If anesthetic vapor delivery is planned, an adequate supply is essential to reduce the risk of light anesthesia or recall. This is especially true if an anesthetic agent monitor with a low agent alarm is not being used.

Partially open filler ports are a common cause of leaks that may not be detected if the vaporizer control dial is not open when a leak test is performed. This leak source can be minimized by tightly closing filler ports. Newer vaporizer designs have filling systems that automatically close the filler port when filling is completed.

High and low anesthetic agent alarms are useful to help prevent over- or under-dosage of anesthetic vapor. Use of these alarms is encouraged and they should be set to the appropriate limits and enabled.

  1. Verify that there are no leaks in the gas supply lines between the flowmeters and the common gas outlet.

The gas supply in this part of the anesthesia delivery system passes through the anesthetic vaporizer(s) on most anesthesia delivery systems. In order to perform a thorough leak test, each vaporizer must be turned on individually to check for leaks at the vaporizer mount(s) or inside the vaporizer. Furthermore, some machines have a check valve between the flowmeters and the common gas outlet, requiring a negative pressure test to adequately check for leaks.

Automated checkout procedures typically include a leak test but may not evaluate leaks at the vaporizer especially if the vaporizer is not turned on during the leak test. When relying upon automated testing to evaluate the system for leaks, the automated leak test would need to be repeated for each vaporizer in place. This test should also be completed whenever a vaporizer is changed.

The risk of a leak at the vaporizer depends upon the vaporizer design. Vaporizer designs where the filler port closes automatically after filling can reduce the risk of leaks.
Technicians can provide useful assistance with this aspect of the machine checkout since it can be time consuming.

  1. Test scavenging system function.

A properly functioning scavenging system prevents room contamination by anesthetic gases.

  • Proper function depends upon correct connections between the scavenging system and the anesthesia delivery system. These connections should be checked daily by a provider or technician.
  • Depending upon the scavenging system design, proper function may also require that the vacuum level is adequate which should also be confirmed daily.
  • Some scavenging systems have mechanical positive and negative pressure relief valves. Positive and negative pressure relief is important to protect the patient circuit from pressure fluctuations related to the scavenging system. Proper checkout of the scavenging system should ensure that positive and negative pressure relief is functioning properly. Due to the complexity of checking for effective positive and negative pressure relief, and the variations in scavenging system design, a properly trained technician can facilitate this aspect of the checkout process.
  1. Calibrate, or verify calibration of, the oxygen monitor and check the low oxygen alarm.

Continuous monitoring of the inspired oxygen concentration is the last line of defense against delivering hypoxic gas concentrations to the patient. The oxygen monitor is essential for detecting adulteration of the oxygen supply.

  • Most oxygen monitors require calibration once daily, although some are self-calibrating. For self-calibrating oxygen monitors, they should be verified to read 21% when sampling room air. This is a step that is easily completed by a trained technician.
  • When more than one oxygen monitor is present, the primary sensor which will be relied upon for oxygen monitoring should be checked.
  • The low oxygen concentration alarm should also be checked at this time by setting the alarm above the measured oxygen concentration and confirming that an audible alarm signal is generated.
  1. Verify carbon dioxide absorbent is not exhausted.

Proper function of a circle anesthesia system relies on the absorbent to remove carbon dioxide from rebreathed gas. Exhausted absorbent as indicated by the characteristic color change should be replaced. It is possible for absorbent material to lose the ability to absorb CO2 yet the characteristic color change may be absent or difficult to see. Some newer absorbents do change color when desiccated.

Capnography should be utilized for every anesthetic and, when using a circle anesthesia system, rebreathing carbon dioxide as indicated by an inspired CO2 concentration > 0 can also indicate exhausted absorbent.

  1. Breathing system pressure and leak testing.

The breathing system pressure and leak test should be performed with the circuit configuration to be used during anesthetic delivery. If any components of the circuit are changed after this test is completed, the test should be performed again. Although the anesthesia provider should perform this test before each use, anesthesia technicians who replace and assemble circuits can also perform this check and add redundancy to this important checkout procedure.

Proper testing will demonstrate that pressure can be developed in the breathing system during both manual and mechanical ventilation and that pressure can be relieved during manual ventilation by opening the APL valve.

Automated testing is often implemented in the newer anesthesia delivery systems to evaluate the system for leaks and also to determine the compliance of the breathing system. The compliance value determined during this testing will be used to automatically adjust the volume delivered by the ventilator to maintain a constant volume delivery to the patient. It is important that the circuit configuration that is to be used be in place during the test.

  1. Verify that gas flows properly through the breathing circuit during both inspiration and exhalation.

Pressure and leak testing does not identify all obstructions in the breathing circuit or confirm proper function of the inspiratory and expiratory unidirectional valves. A test lung or second reservoir bag can be used to confirm that flow through the circuit is unimpeded. Complete testing includes both manual and mechanical ventilation.

The presence of the unidirectional valves can be assessed visually during the PAC. Proper function of these valves cannot be visually assessed since subtle valve incompetence may not be detected. Checkout procedures to identify valve incompetence which may not be visually obvious can be implemented but are typically too complex for daily testing. A trained technician can perform regular valve competence tests.

Capnography should be used during every anesthetic and the presence of carbon dioxide in the inspired gases can help to detect an incompetent valve.

  1. Document completion of checkout procedures.
Each individual responsible for checkout procedures should document completion of these procedures. Documentation gives credit for completing the job and can be helpful if an adverse event should occur. Some automated checkout systems maintain an audit trail of completed checkout procedures that are dated and timed.
  1. Confirm ventilator settings and evaluate readiness to deliver anesthesia care. (ANESTHESIA TIME OUT)

This step is intended to avoid errors due to production pressure or other sources of haste. The goal is to confirm that appropriate checks have been completed and that essential equipment is indeed available. The concept is analogous to the “time out” used to confirm patient identity and surgical site prior to incision.

Improper ventilator settings can be harmful especially if a small patient is following a much larger patient or vice versa. Pressure limit settings (when available) should be used to prevent excessive volume delivery from improper ventilator settings.

Items to check:

  • Monitors functional?
  • Capnogram present?
  • Oxygen saturation by pulse oximetry measured?
  • Flowmeter and ventilator settings proper?
  • Manual/ventilator switch set to manual?
  • Vaporizer(s) adequately filled?

Timing

Perform the entire checklist daily.

Repeat the following items before each case:

  • 2: Verify patient suction is adequate to clear the airway
  • 4: Verify availability of required monitors, including alarms.
  • 7: Verify that vaporizers are adequately filled and if applicable that the filler ports are tightly closed.
  • 11: Verify carbon dioxide absorbent is not exhausted
  • 12: Breathing system pressure and leak testing.
  • 13: Verify that gas flows properly through the breathing circuit during both inspiration and exhalation.
  • 14: Document completion of checkout procedures.
  • 15: Confirm ventilator settings and evaluate readiness to deliver anesthesia care. (ANESTHESIA TIME OUT)

leak check How to do a high pressure leak check. Click on the thumbnail, or on the underlined text, to see the larger version (255 KB).





Check obstruction How to check that gas flow in the breathing circuit is not obstructed. Click on the thumbnail, or on the underlined text, to see the larger version (275 KB).





Check obstruction Another way to check that gas flow in the breathing circuit is not obstructed. Click on the thumbnail, or on the underlined text, to see the larger version (214 KB).

Users may not want to breathe through the circuit for hygienic reasons, or to avoid exposure to gases or vapors.



Check I/E bvalves How to do a more sensitive test for obstruction of the inspiratory and expiratory unidirectional valves in the breathing circuit. Click on the thumbnail, or on the underlined text, to see the larger version (385 KB).






Electronic checklists

Regardless of the model of gas machine, users must be able to answer at least three patient safety questions affirmatively upon completion of the electronic or automatic portion of the checklist:

  1. Is there oxygen in the oxygen line?
  2. Can they take a breath, and exhale it?
  3. Is the reassembled circuit free of leaks? Can I give a breath?

The newer machines (ADU, Fabius GS, Apollo, NM 6000, Aisys) have system checkout routines that are electronic and automated. The operator follows instructions to activate flows of gases, occlude the breathing circuit during the leak check, switch from manual to mechanical ventilation, open and close the pop off valve, and manually check various functions (suction, or emergency oxygen cylinder supply). All these machine checklists require users to check certain aspects on their own, and these aspects vary from machine to machine, which creates a need for training on each machine anesthetists use.

Local departments must create checklist procedures for each type of gas machine they own. Electronic checklists can be expected to cover most or all the steps of the PAC 2008, but this is apparent only after some study, because each checklist differs in important respects. Models may differ on whether (or how) they check oxygen monitoring, vaporizer leaks, etc. You can see samples posted at Sample PAC procedures. Electronic checklists may (or may not) require that the gas analysis aspiration sampling line is disconnected before the breathing circuit is occluded by attaching it to a post. Electronic checklists may (or may not) require the operator to repeat leak tests with each vaporizer turned on.

Electronic system checkout is logged, but may be bypassed in an emergency. Though it takes 3 to 6 minutes, the operator can perform other tasks simultaneously (such as filling syringes), so it does not appreciably slow morning preparation, unless one had not been accustomed to performing a morning gas machine checklist at all (!).

Minimum test under life-threatening conditions

While there is no universally accepted machine checklist less than the full PAC, situations do arise in anesthesia (e.g. for trauma or emergency cesarean section) where there is neither time nor opportunity to fully check the anesthesia gas machine. The PAC 2008 states "The PAC is essential to safe care but should not delay initiating care if the patient needs are so urgent that time taken to complete the PAC could worsen the patientís outcome."

The following checklist is suggested for these situations. It requires little if any additional time, and can add greatly to safety, and hence, peace of mind.

  1. High pressure test of the breathing circuit
  2. Check patient suction
  3. Observe and/or palpate breathing bag during preoxygenation. This ensures

With all new machines, the electronic checklist can be bypassed in emergencies. Whether the quick minimum test above is acceptable must be determined by each clinical practice. It has been suggested that the NM 6000 be left on if trauma or obstetric cases must be done on a moment's notice (Anesthesiology 2001;95:567-8). .The NM 6000 checklist can only be bypassed nine times. The Aisys (or ADU) checklist can be bypassed an indefinite number of times, but it will display a visible, nagging message until the electronic checkout is performed.

Checklist for older anesthesia gas machines which do NOT have an electronic checklist

This modification of the checklist was agreed upon after local peer review; it is suggested that peer review should occur anywhere such a modification is contemplated.

Introduction The anesthesia gas machine must be equipped with an ascending bellows ventilator and certain monitors (capnograph, pulse oximeter, oxygen analyzer, spirometer, breathing system pressure monitor with high and low pressure alarms). If not so equipped, the checklist must be modified.

  1. Verify backup ventilation equipment is available & functioning.
    • Contaminated oxygen supply, loss of oxygen supply pressure, and obstruction of the breathing system, though rare, cause the machine to be totally inoperable. So check for that Ambu!
  2. Check oxygen cylinder supply
    • One cylinder must be at least half full (1000 psi).
    • It is not necessary to:
      1. Check any other cylinders beside oxygen
      2. "Bleed" the pressure off the cylinder pressure gauge after checking
    • Leave cylinder closed after checking.
    • While you're behind the machine, check suction, Ambu bag and extra circuit present. Also: gas analysis scavenged, scavenger caps all present, location of circuit breakers, any loose pipeline, electrical, or etc. connections, head strap, tank wrench, and color/date of CO2 absorbent.
  3. Check central pipeline supplies.
    • Check for proper connection at wall
    • Check the pipeline pressure gauge- should read approximately 50 psi.
    • It is not necessary to unhook pipeline connections at wall.
  4. Check initial status of low pressure system.
    • Remove oxygen analyzer sensor and begin calibration.
    • Check liquid level and fill vaporizers if necessary; fill ports tightly capped.
    • Check vaporizer interlock.
  5. Perform leak check of low pressure system.
    • Leaks as low as 100 mL/min may lead to critical decrease in the concentration of volatile anesthetic (creating a risk for intraoperative awareness), or permit hypoxic mixtures under certain circumstances.
    • Negative pressure leak test (10 sec.) is recommended.
    • Repeat for each vaporizer.
  6. Turn master switch on.
  7. Test flowmeters.
    • Check for damage, full range, hypoxic guard.
  8. Calibrate oxygen monitor
    • Final line of defense against hypoxic mixtures. Trust it until you can prove it wrong. Mandatory for all general anesthetics, or whenever using the breathing circuit (for example during sedation)
    • Calibrate/daily check: expose to room air and allow to equilibrate (2 min). Then expose to oxygen source and ensure it reads near 100%
  9. Check initial status of breathing system
    • Assemble circuit with all accessories.
  10. Test ventilation systems and unidirectional valves
    • Test ventilator and observe action of unidirectional valves.
  11. Perform leak check of breathing system
    • The "usual" high pressure check.
    • Let the gas out of the circuit through the popoff (APL) valve, not the elbow.
  12. Adjust and check scavenging system.
    • If active (suction) is applied to a closed scavenger interface, check the positive and negative pressure relief valves of the interface.
    • If open interface, ensure that adequate suction is applied (the indicator float between the scribed lines).
  13. Check, calibrate, set alarm limits of all monitors
  14. Check final status of machine.
    • Vaporizers off
    • Bag/Vent switch to "bag" mode
    • APL open
    • Zero flows on flowmeters
    • Suction adequate
    • Breathing system ready
  15. Anesthesia Time Out immediately before induction
    • All monitors attached, functional?
      • Capnogram, SpO2 waveforms?
    • Flowmeter, vent settings proper?
    • Manual/vent switch to manual and APL open?
    • Vaporizers filled?

    Repeat check before each patient: Suction, Absorbent, Vaporizers, Breathing circuit (high pressure leak test, unidirectional valves), Monitors/alarms, Anesthesia Time out.

Negative pressure leak check for older machines

Why neg. pressure check? Diagram of area proximal to check valve which is not checked with high-pressure methods. Click on the thumbnail, or on the underlined text, to see the larger version (25 KB).

Unidirectional valves (check valves) are present in some machines between the vaporizers and the common gas outlet. Without them (or internal vaporizer design modifications), the cycling of positive pressure in the breathing circuit leads to increases in vaporizer output (the pumping effect). A high pressure check of the breathing circuit will not detect leaks upstream of these valves, since the high pressure in the breathing circuit will only be transmitted upstream to the check valve, and no further. These upstream areas are vulnerable areas. Glass flowtubes, internal vaporizer seals, and rubber O-rings are susceptible to failure.

Neg pressure leak test deviceNegative pressure leak test device. Click on the thumbnail, or on the underlined text, to see the larger version (12 KB).

A universal leak check that will work on any older anesthesia machine is the negative pressure leak test. Unfortunately, this step is not well-understood or practiced often enough, in part due to its reliance on an accessory suction bulb, which is meant to be applied to the common gas outlet. The bulb is pumped until it flattens: it will remain flat if no internal leaks are present proximal to the common gas outlet. The test is repeated with each vaporizer turned on.

Risk management, quality assurance, standards, and medicolegal

Risk Management encompasses pre and post-op visits, avoiding treating patients indifferently, maintaining vigilance and high standards of care, peer review, and continuing education. For anesthesia equipment, it means daily checks and appropriate maintenance. The Safe Medical Device Act 1990 mandates a report to the FDA when equipment contributes to severe injury or death (you can see examples in the MAUDE Database [Manufacturer and User Facility Device Experience]).

Preventive maintenance should be done at regular intervals as called for in the operating manuals by qualified, factory-trained and approved service technicians. Vaporizers should be inspected, tested and calibrated per manufacturer's guidelines.

Quality assurance deals with objective, systematic monitoring, and the evaluation of the quality and appropriateness of patient care. Waste anesthesia gas testing can help to protect personnel and identify machines with problems. Anesthesia personnel can be held liable for knowledge of material in the anesthesia gas machine operating manual, maintenance guide, and any warnings given by the manufacturer (which are monitored and approved by the FDA the same way drug package inserts are).

Equipment that is available and functional helps anesthetists ensure patient safety. Capnography and pulse oximetry are so ubiquitous, that they may be considered integral parts of the machine itself. Gas machines are required to have a breathing system disconnect monitor with alarm, an oxygen analyzer, and an oxygen supply failure alarm. These monitoring standards also mandate a safety check daily and between cases (as needed), preventive maintenance, and machines that conform to national and state standards.

Cleaning and sterilization

It is controversial whether equipment like breathing circuits can transmit infection, though some cases have certainly been documented. Most, if not all, would agree that sterilization is essential after use on a patient with known or suspected infection of the respiratory tract, especially with virulent organisms like pseudomonas aeruginosa. Likewise, we should protect compromised patients from contamination arising from our equipment. In any case, handwashing between patients, as well as universal precautions are mandatory in anesthetic practice.

Housekeeping during administration of anesthesia will limit the spread of contamination:

Cleaning equipment means removal of foreign matter without special attempts to kill microorganisms. Equipment should be pre-rinsed as soon as possible after use to prevent drying of organic material; then soaked, removal of soil, rinsing and drying.

Sterilization

Moist heat methods

Liquid sterilization

Useful for heat sensitive equipment, but recontamination possible during drying and re-wrapping. Of several agents (chlorhexidine Hibitane®, phenolic compounds, hexachlorophene, ethyl or isopropyl alcohols), glutaraldehyde is the only one effective against both tubercule bacillus and viruses.

The Steris system uses peracetic acid in a low-temperature, 30 minute cycle to sterilize objects such as laryngoscope blades and fiberoptic laryngoscopes.

Chemical gas sterilization

Ethylene oxide (ETO) is a synthetic gas widely used, especially for heat or moisture-sensitive items like rubber and plastic. Kills bacteria, spores, fungi, larger viruses. Can be various patient reactions if not aerated (in wrapper) sufficiently after ETO exposure. The gas is also explosive and toxic.

Other means

Gamma radiation kills all bacteria, spores and viruses. Used for sterilization of disposable equipment - not practical for everyday needs of hospitals.

Care of specific equipment

The Centers for Disease Control has a collection of useful information relating to bloodborne diseases and universal precautions.


Questions?
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