A Dangerous Defect in a Heat and Moisture Exchanger

Prados, Wilfred

doi:10.1097/00000542-198911000-00033

Cited by 15 publications

(10 citation statements)

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“…3 However, Pall breathing circuit filters have been validated to remove a range of indicator organisms and clinically relevant pathogens including staphyloccocus aureus, 4 mycobacterium tuberculosis, 5 human immunodeficiency virus 6 and hepatitis C virus. 7 Consequently Pall breathing circuit filters are used widely to prevent cross infection via breathing systems in anesthesia. Several million Pall breathing circuit filters are used each year for this purpose.…”

Section: Appendixmentioning

confidence: 99%

Rapid and complete occlusion of a heat and moisture exchange filter by pulmonary edema (Clinical report)

Williams¹,

Stacey²

2002

Can J Anesth/J Can Anesth

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Section: Appendixmentioning

confidence: 99%

Rapid and complete occlusion of a heat and moisture exchange filter by pulmonary edema (Clinical report)

Williams¹,

Stacey²

2002

Can J Anesth/J Can Anesth

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“…Although COHb cannot be detected by pulse oximetry, it is possible to detect COHb with blood gas analysers if they also have carbon monoxide-oximetry. Where elevated levels of carbon monoxide have been demonstrated, it may be reasonable 77 Pryne, 86 Campbell 26 Increased Airway Resistance Aarhus, 1 Barnes, 9 Buckley, 24 Stacey, 97 Villafaine, 104 Cohen 30 Obstruction Barton, 10 Australian Therapeutic Device Bulletin, 50 Prados, 84 Prasad, 85 Barnes and Normoyle, 9 Walton, 105 Williams and Stacey 116…”

Section: Filters and Hmes And Carbon Monoxide Productionmentioning

confidence: 99%

Hidden hazards and dangers associated with the use of HME/filters in breathing circuits. Their effect on toxic metabolite production, pulse oximetry and airway resistance

Lawes¹

2003

British Journal of Anaesthesia

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Current airway dust ®lter technology emanates from the USA mining industry during the 1930s. It was further developed and improved by the USA military during World War II to prevent workers from inhaling very ®ne radioactive particles in the nuclear industry. These later ®lters we now recognize as high ef®ciency particulate air ®lters (HEPA).The ef®ciency of ®lters varies according to the number and size of particles they capture. Filters may be classi®ed commonly as 95, 99.95, and 99.97% ef®cient (95, 99 and 100, respectively). The higher the ef®ciency the higher the classi®cation number used. The ef®ciency of ®lters may also be affected by volatile chemicals which may be inhaled with the particles. Industrial ®lters which are categorized by the above system may also have a pre®x of N, R, or P; N for Not resistant to oil, R for Resistant to oil, and P for oil Proof; thus, a ®lter would be classi®ed as for example a P100. Requirements for military and environmental biohazard ®lters are based on these classi®cations and surprisingly may only achieve 95% ef®ciency.A generally perceived increased threat from biological hazards that may be inhaled, including bioterrorism threats, especially in hospital environments, has increased interest in respiratory ®lters. 94 Protecting personnel from inhaled biological hazards requires a ®lter ef®ciency of several orders of magnitude greater than the industrial dust ®lters used in respirators alluded to above. As few as 10 inhaled smallpox viruses may be suf®cient to infect patients with the disease. 94 This has resulted in the sub-classi®cation of HEPA ®lters into true HEPA ®lters and HEPA type ®lters. A further sub group has also developed. ULPA ®lters (Ultra Low Penetration Air) and`absolute' ®lters are designed for industrial applications such as microelectronic clean rooms, but have too high a resistance for medical breathing apparatus.All HEPA ®lters are manufactured from glass ®bre materials supported on a rigid frame. In order to reduce resistance to air¯ow and increase ef®ciency, the surface area is increased by pleating. Filtration is achieved for larger particles (>0.3 m) by inertial impaction and interception; smaller particles are captured by Brownian diffusion. The size of particles used to test ®lters is measured in microns. Microns are units used for particles that can be seen with a light microscope. A micron is a thousandth of a millimeter, which is in turn a thousandth of a meter (1 m=1000 nm or 0.001 mm). The variation in ®ltration ef®ciency is tested by the British BS3928 Sodium Flame method and the USA Hot DOP method. The most dif®cult particle size to capture by ®ltration is a particle of 0.3 m as at this size the effects of inertial impaction, interception and Brownian motion are least effective. Particles of 0.3 m are also most likely to be deposited in the lungs if inhaled. The di-octyl-phthalate (DOP) test, used for testing the ef®ciency of ®lters, takes advantage of the properties of DOP. In particulate form, DOP has a constant mean diameter of 0.3 ...

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“…Humidification of respiratory gases has been shown to reduce the incidence of tracheal tube obstructions in premature infants (22). However, several reports have shown that humidifiers can be extremely dangerous (23,24).…”

Section: Humidification Reduces Tracheal Tube Obstructionmentioning

confidence: 99%

Humidification in paediatric anaesthesia

Brock‐Utne

2000

Pediatric Anesthesia

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A Dangerous Defect in a Heat and Moisture Exchanger

Cited by 15 publications

References 0 publications

Rapid and complete occlusion of a heat and moisture exchange filter by pulmonary edema (Clinical report)

Rapid and complete occlusion of a heat and moisture exchange filter by pulmonary edema (Clinical report)

Hidden hazards and dangers associated with the use of HME/filters in breathing circuits. Their effect on toxic metabolite production, pulse oximetry and airway resistance

Humidification in paediatric anaesthesia

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