1、TECHNICAL REPORT ISO TR 11991 First edition 1995-07-15 Guidance on airway management during laser surgery of upper airway Guide pour assurer Ia Ventilation au cours dopkations par laser des voies respiratoires suphieures Reference number ISO/TR 11991 :1995(E) ISO/TR 11991:1995(E) Contents Page 1 Sco
2、pe 1 2 References 1 3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 Ideal proper-Ges of tracheal tubes for use with lasers . . . . . . . . . . .
3、 . . . . . . . . . . . . . . . . . . . . . 3 4.1 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4.2 Design . 3 4.3 Packaging and labellin
4、g 4 5 Description of current practices which reduce the risk of airway fire 4 5.1 Non-intubation techniques 4 5.2 Intubation techniques . 5 5.3 Management of airway fires . 10 Tables 1 Combustion properties of conventional tracheal tube materials . . . . . . . . . . . . . . . 11 2 Primary emergency
5、management following recognition of airway fire . . . 11 3 Secondary emergency management following recognition of an airway fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、. . . . . . . . . . . . . . . . . . . . . . . 12 Annex A Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 0 ISO 1995 All rights reserved. Unless ot
7、herwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Gase Postale 56 l CH-121 1 Geneve
8、 20 l Switzerland Printed in Switzerland ii 0 ISO ISO/TR 11991:1995(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO techn
9、ical committees. Esch member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govem- mental and non-govemmental, in liaison with ISO, also take part in the work. ISO collaborates closely
10、with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The main task of technical committees is to prepare International Standards, but in exceptional circumstances a technical committee may propose the publication of a Technical Report of one of
11、 the following types: type 1, when the required support cannot be obtained International Standard, despite repeated efforts; for the publication of an - type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an
12、 agreement on an International Standard; - type 3, when a technical committee has collected data of a different kind fiom that which is normally published as an International Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of pu
13、blication, to decide whether they tan be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed until the data they provide are considered to be no longer valid or useful. ISO/TR 11991, which is a Technical Report of type 3, was prepared by Techn
14、ical Committee ISO/TC 12 1, Anuesthetic and respiratory equipment, Subcornmittee SC 2, Tracheal tubes and other equipment. This document is being issued as a type 3 Technical Report to summarize current methods for airway management during laser surgery of the upper airway to minimize the risk of fn
15、e. (See the Introduction.) . . . Ill ISO/TR 11991:1995(E) 0 ISO Introduction This guide provides information for clinicians for appropriate selection of airway devices for operations on the upper airway, including the larynx, in which a laser is used. It also provides information for the appropriate
16、 selection of intubation and non-intubation techniques. Tracheal tubes are commonly used in patients during general anaesthesia for such operations. These tubes provide effective control of Ventilation and oxygenation, protect the airway from aspiration (if cuffed), and allow monitoring of Ventilati
17、on through capnography and spirometry. A laser is a Source of intense light energy which tan provide an ignition Source. so , that a fire is a risk in the operative field. Risk of fire is particularly enhanced in oxidant (0, or N,O) enriched atmospheres. Tracheal tubes assist Ventilation and Patient
18、 monitoring but may be ignited by the laser in these circumstances. In these procedures, the clinician must be aware of tlie risk of fire. Fire requires three elements: an ignition Source, a combustible material, and an Oxygen Source. These three are sometimes referred to as “the fire triangle”. Dur
19、ing laser surgery on the upper airway, all three elements are often present. The laser is an intense light energy which tan provide a Source of ignition. Tracheal tubes when present are usually made of combustible material. Finally, most patients are treated in an oxidant-enriched atmosphere. Care t
20、o minimize these three elements is essential to avoid a fire during laser surgery of the upper airway. Of the numerous methods available for airway management during laser operations on the upper airway, each has its own risks and advantages. This guide summarizes the current methods and the applica
21、tions, advantages, and disadvantages of each. The guide serves to assist the anaesthetist and surgeon in their joint cdecision regarding selection of the most appropriate method tob ovgenate and ventilate the Patient during laser surgery involving the upper airway. This guide does not recommend any
22、one method of airway management. The test datakluded in Table 1 of this guide are based upon continuous beam CO, Lasers. While this data may not be directly applicable to other wavelengths or beam modes (such as super pulse), the basic principles still apply. Decisigns regarding practice methods tan
23、 onlv be made by the clinicians caring for the Patient, having knowledge of the clinical circumstances, available expertise, and technology, e.g. the properties of the specific laser wavelength planned for the surgery. Other complications of laser surgery not involving aiway management may be found
24、in ANSI 2136.1 (l), and ANSI 2136.3 (2), CAN/CSA 2386 M91 (3). TECHNICAL REPORT ISO ISO/TR 11991:1995(E) Guidance on airway management during laser surgery of upper airway 1 Scope At present there is no way to avoid completely the risk of an airway fire when a laser is used in the airway. This guide
25、 is intended to help minimize this risk by listing a) those characteristics of a tracheal tube that make it most suitable for laser airway operations, recognizing that it may not be possible in practice to produce a device combining such characteristics; b) several Standard practices that reduce the
26、 risk of airway fire during laser operations on the airway; c) recommendations for emergency management should an airway fire occur. This guide represents current knowledge at the time of publication and is subject to review. This guide does not address management of the Patient with a tracheostomy.
27、 This guide is also intended to assist related groups, such as laser safety committees. 2 References ISO 5361-1: 1988, Tracheal tubes - Part 1: General requirements. ISO 5361-2: 1993, Tracheal tubes - Part 2: Oro-tracheal and naso-tracheal tubes of Magill type (plain and cuffed). ISO 5361-5: 1984, T
28、racheal tubes - Part 5: Requirements and methods of test for cuffs and tubes. ISO 7228: 1993, Tracheal tube connectors. ISO 10993-l:- l) Biological evaluation of medical devices ) - Part 1: Evaluation and testing. 1) To be published. (Revision of ISO 10993- 1: 1992) ISO/TR 11991:1995(E) 0 ISO 3 Term
29、inology For the purpose of this technical report, the following definitions apply. 3.1 anatomical airway : Natura1 pathways through which respired gases pass in either direction between the atmosphere and the alveoli. 3.2 combustion : Rapid 33 F,O, : The fractional 3.4 flammability : The a Oxidation
30、 to produce heat and light. concentration of Oxygen in inspired gas. bility to sustain combustion. 3.5 ignitability : The ability to initiate combustion. 3.6 intubation : Placement of a tracheal tube into the trachea. 3.7 laser platform : A surgical handpiece made of a non-combustible material with
31、a non-reflective surface. The end of the device is placed behind the target tissue as a backstop for the laser. 3.8 laser plume : Gaseous and particulate by-products of combustion and/or pyrolysis produced by the effect of laser enerw upon a target. 3.9 oxidant enriched atmosphere : Any atmosphere t
32、hat contains oxidants (0, N,O) in total concentration greater than 25% of volume at ambient pressure. 3.10 Oxygen index of flammability : The minimum concentration of 0, in N, necessary to support a candle-like flame for a given substance. 3.11 pledget (cottonoid) : A compress, usually of gauze or a
33、bsorbent cotton. 3.12 power density (irradiance) : The power delivered by a laser beam per unit area of irradiated surface (Spot size), expressed as Watts per Square centimetre. 3.13 pyrolysis : Transformation of a compound into one or rnore other substances by heat alone (without Oxidation). 3.14 s
34、pecular reflectance : The characteristics of a material to reflect light in such a way that the angle of reflection is equal to the angle of incidence, such as the reflectance from a mirror. 3.15 thermal conductivitv : Time rate of heat flow through unit area, per unit temperature gradient, in the d
35、irection perpendicular to the area. 1 3.16 upper anatomical airway (the upper airway) : The airway above the laryngotracheal junction. 2 0 ISO ISO/TR 11991:1995(E) 4 Ideal properties of tracheal tubes for use with lasen 4.1 Materials The materials used for the manufacture of the part of the tracheal
36、 tube intended to lie in the upper airway should have the following characteristics: 4.1.1 Ignitability Materials should be resistant to ignition by a laser beam in the presence of 100 % 0 2. 4.1.2 Flammability Materials should not maintain combustion in 100 % 0,. 4.13 Specular reflectance Materials
37、 should have no specular reflectance so as to avoid injury to non-targeted tissue. 4.1.4 Heat transfer Materials should minimize heat transfer that may darnage adjacent tissue. 4.1.5 Products of pyrolysis and combustion The products of pyrolysis and combustion should satisfy appropriate biological s
38、afety test as specified in ISO 10993-1. 4.2 Design 4.2.1 General Tubes should comply with the requirements specified in ISO 53614, ISO 5361-2, ISO 5361-5 and ISO 7228. 4.2.2 Integrity In the event of tube ignition, integrity of the tube and attached components should be maintained so that they tan b
39、e immediately removed intact. 4.23 Transparency The material used for the manufacture of the tracheal tube should be sufficiently optically transparent or translucent to enable condensation of airway vapour and evidente of combustion to be seen within its lumen. ISO/TR 11991:1995(E) 0 ISO 4.2.4 Cuff
40、 inflation The tracheal tube cuff should be capable of being inflated with liquid and rapidly deflated under normal conditions of use. 4.2.5 The cuff and inflation system The cuff and inflation system, if exposed, should be laser resistant. 43 Packaging and labelling 43.1 The tracheal tube and attac
41、hed components should be preassembled and individually packaged. 43.2 The tube should be intended and labelled for Single use. 5 Description of current practices which reduce the risk of aixway fire At present there is no way to completely avoid the risk of an airway fire when a laser is used in the
42、 airway. The following are descriptions of current practices that reduce the risk of airway fire. Accompanying each practice is a discussion of its advantages and disadvantages. No significance should be attributed to the Order in which these practices are presented. 5.1 Non-intubation techniques Th
43、ese methods of Ventilation do not use a tracheal tube. 5.1.1 Spontaneous breathing techniques With the Patient breathing spontaneously, gas with or without supplemental Oxygen and/or potent inhalation anaesthetic is insufflated into the operating laryngoscope, bronchoscope, a metal hook, or a cathet
44、er (4). The anaesthetic may be supplemented with intravenous agents and/or regional anaesthesia to the airway. Advantages : There is no tracheal tube in the airway so that the risk of fire is reduced. The method also provides excellent visibility of the surgical field and avoids potential trauma to
45、the airway that use of a tracheal tube might Cause. Dkadvantages : Hypoventilation is a risk which may go undetected since capnography is difficult and inaccurate, and spirometry cannot be used. Pulmonary aspiration of gastric contents and/or laser plume tan also occur. Ventilation cannot be assiste
46、d or controlled. Depth of anaesthesia may fluctuate SO that Patient movement tan occur. Insufflation techniques make scavenging anaesthetic gases difficult. The risk of fire is increased if a flammable catheter is used as the insufflation device. 0 ISO ISO/TR 11991:1995(E) 51.2 Apnoeic techniques Th
47、e Patient is ventilated through a mask, tracheal tube, or bronchoscope, using Oxygen-enriched gas, with or without potent inhalation anaesthetic. During Ventilation, the laser is not used. Ventilation is then temporarily discontinued and the mask or tracheal tube is removed. During apnoea, laser res
48、ection is performed. After a period of time, laser resection is stopped and Ventilation is resumed. Periods of Ventilation altemate with laser resection/apnoea in this manner. Advantages : There is no tracheal tube in the airway so that the risk of fire is reduced. The method also provides excellent
49、 visibility of the surgical field and avoids potential trauma to the airway that use of a tracheal tube might Cause. Disadvantages : Hypoventilation is a risk which may go undetected since capnography and spirometxy are not applicable during apnoea. Pulmonary aspiration of gastric contents and/or laser plume may occur. There is a potential for airway trauma from repeated instrumentation. 5.1.3 Jet Ventilation technique A metal needle or similar device is mounted either in the operating laryngoscope or placed below the site of Operation and attached to a jet injector. A high-velocity jet
