ISO 9360-1:2000 pdf download

ISO 9360-1:2000 pdf download.Anaesthetic and respiratory equipment—Heat and moisture exchangers (HMEs) forhumidifying respired gases in humans —Part 1: HMEs for use with minimum tidal volumesof 250 ml.
If the HME incorporates an accessory port, that port shall not accept the 15 mm or 22 mm connectors specified in
ISO 5356-1 or ISO 5356-2.
5.3 Packaging of sterile HME
HME supplied sterile shall comply with the requirements specified in ISO 11607.
6 Test methods
6.1 General
The apparatus and test methods specified in 6.2 to 6.5 are not intended to exclude the use of other measuring devices or methods yielding results of an accuracy equal to or greater than those specified. In the case of a dispute, the methods given in this part of ISO 9360 shall be the reference methods.
The tests shall be performed at a temperature of 23 °C ± 2 °C, a RH of 50 % ± 20 %, and an atmospheric pressure of 86 kPato 106 kPa.
6.2 Measurement of moisture loss
6.2.1 Principle
the performance of an HME shall be measured by recording the mass of water lost from the test apparatus specified in 6.2.2.
6.2.2 Test apparatus
The test apparatus (Figure 1) shall comprise the following components.
6.2.2.1 Bidirectional flow generator.
This is a mechanically-driven piston used to produce a flow having sinusoidal waveform.
6.2.2.2 Humidity generator (HG), consisting of
a) a heated water bath (Figure 2) through which air is bubbled in both directions;
b) a rigid cylindrical reservoir (Figure 3) with a maximum volume of 7 I and a diameter of approximately 150 mm, containing a 2 I reservoir bag;
c) a thermally insulated chamber (Figure 4), which contains the water bath, the reservoir and a heat source.
6.2.2.3 Air delivery system (Figure 5), consisting of a T-piece with an internal diameter greater than 15 mm, and an exhaust tube at least 200 mm in length.
6.2.2.4 Weighing equipment, with an accuracy of ± 0,1 g or better in the range of the mass to be measured.
6.2.2.5 Flowrate measuring equipment, with an accuracy of at least 5 % of the reading.
6.2.2.6 Calibration HME (Figure 6) consisting of a housing containing 81 polyvinyl chloride (PVC) tubes arranged in a 9 x 9 array, each with an internal diameter of 2 mm, an external diameter of 4 mm, and a length of 50 mm.
When the apparatus has been constructed and operated as specified in 6.2.2, the moisture loss from the humidity generator with the calibration HME will be as shown in Table 3.
As HMEs are a component of the total breathing system connected to a patient, it was not considered necessary or practical to specify limits for gas leakage, compliance, internal volume, pressure drop or moisture loss. Rather, by requiring the manufacturer to disclose these parameters, the user can make a judgement on the suitability of the HME for particular use as part of the total system. The following presents the rationale for particular subclauses in the main body of this part of ISO 9360. The numbering therefore is not consecutive.
6.2 Measurement of moisture loss
It is impossible to specify testing equipment which will accurately mimic the physiological, anatomical and pathological parameters that may interact to affect the performance of an HME.
The test apparatus specified in this part of ISO 9360 is intended to simulate the use of an HME. Hence the moisture-conserving performance of an HME determined by this part of ISO 9360 provides comparative data only.
In order to simulate the humidification of respired air, a humidification generator is used. The output of the generator at 37 °C (when maintained) that is not returned by the HME under test is determined by the mass loss of the generator during the experimental procedure. Note that the moisture retained in the HME is considered moisture lost from the test apparatus.
In order to confirm the correct function of the test apparatus, a calibration HME is used. The moisture retention characteristics of this HME are known and need to be shown to be reproduceable by the test apparatus within defined limits.
In order to simulate inspiratory and expiratory air movement in a spontaneously breathing patient, four flow waveforms were investigated:
a) constant inspiratory flowrate and exponentially-decaying expiratory flowrate;
b) constant inspiratory flowrate and constant expiratory flowrate;
c) sinewave flow with an l:E ratio of 1:2;
d) sinewave flow with an I:E ratio of 1:1.
The water loss from the humidity generator was measured using a calibration HME, with each flow waveform. No important difference, within experimental error, was found.
Hence, as the sinusoidal waveform flow with an l:E ratio of 1:1 is the most easily defined and the least affected by experimental changes, it was selected as the preferred flow waveform for testing HME.
6.2.2.2 To record the mass of water lost from the apparatus specified in 6.2.2, heated humidified air is passed to and from the HME by a bidirectional flow generator to simulate inspiration and expiration.
b) The diameter and volume of the rigid chamber were chosen so that the reservoir bag did not undergo elastic deformation. This could occur if a smaller chamber were used and the reservoir bag pressed against the walls of the chamber when the bag was inflated.
6.2.3.2 A set of test conditions are specified so that comparisons can be made between different HMEs tested under the same conditions. However, so that the information supplied by the manufacturer is complete, the HME shall also be tested at the minimum and maximum tidal volume recommended by the manufacturer, if these tidal volumes are outside the range specified in Table 2.