Quality assurance, infection protection and control

Aims

Understanding the rationale for quality assurance including ability to correctly describe, document, and ensure quality standards and practice
Prevention of infection transmission

Overview

1. Provide strategies for quality assurance

requirements for equipment quality control
Calibration and Verification
Importance of recognising device measurement errors during calibration and quality checks

2. Provide strategies for hygiene and infection protection and control

Precautions to protect staff and patients
Rationale for regular cleaning
Describe methods for prevention of infection transmission
Performance and record of infection control procedures

Quality Assurance

Quality Control (QC) is the process of measuring and monitoring the quality of the data.
Quality Assurance (QA) is a group of routines and interventions to ensure the data is high quality.
Good QA systems use a robust series of checks before during and after the patients' visit to ensure the results will be accurate and as precise as possible.
QA and QC are valuable tools to ensure that those performing the test can resolve arising issues, providing accurate and meaningful results (best representation of the patient's clinical status).
QA/QC programme can help identify and minimise sources of error.

Pre procedure notes	Familiarise yourself with the equipment and manufacturer instructions on calibration or calibration verification. Spirometer equipment ideally is ISO 26782 compliant and calibration syringe has an in-date certificate and has been pre checked for leaks (daily inspection and monthly leak check must be documented). If using software consult the manufacturer instructions for use. Checks all parts are in good working order before this procedure. Note that room temperature and syringe temperature may negatively affect results. Refer to latest national and international standards.
Calibration types	A calibration verification is the procedure used to validate that the device is within calibration limits (i.e., =/-3% [accuracy tolerance, =/-2.5% for spirometers plus =/-0.5% for calibration syringes]). In calibration mode the equipment will exclude the BTPS factor to the results.
Note on pre-calibrated sensors	Precalibrated sensors must undergo calibration verification. Manufacturers must specify the action to be taken if a pre-calibrated device fails the calibration verification.
Setup procedure	Connect the calibrator (3 L Syringe) securely to the spirometer sensor without causing allowing air to flow through the device. If variable flow is detected during the zero-flow setting procedure or if the zero level has changed significantly, the zero-flow setting procedure must be repeated.
Perform procedure	Fill the syringe completely with air and attach the calibration syringe firmly to the equipment sensor (always use a filter during the calibration of flow sensing equipment).
	Empty the syringe smoothly and completely until a soft click is heard, continuously observe the syringe strokes on the equipment screen. Do not bang the syringe when emptying it, to avoid any damage. Tip: follow the screen or software instructions to aid performance of this procedure. Linearity of the system is assessed as follows: The calibrating manoeuver is performed three times at different flows. The recorded volume should be repeatable: when using a 3L syringe the largest - smallest measured volume should not deviate by more than 90 mL. Repeat above 3 to 5 times, you will be instructed to alter the speed of the air injections (slow, medium and fast) and must comply with the "multi flow" calibration standard (a range varying between 0.5 and 12 L/s with 3-L injection times between 0.5 and 6 s). The resulting simulated FVC values must fall within the 3% range. Each time stamped successful calibration must be stored either within the software or as a print-out.
Calibration result	The measured volume displacement should be within 2.91 and 3.09 at ATPS conditions. Results must be printed or stored for recall later.
Documentation	A log of all quality control findings, repairs and adjustments, and hardware and software updates d Verification of reference value calculations after software updates.
Spirometer	Device Quality Assurance Attention to equipment quality assurance and calibration is an important part of good laboratory practice The minimum requirements are as follows: maintenance of a log of calibration results documentation of repairs or other alterations that return the equipment to acceptable operation recording of dates of computer software and hardware updates or changes recording the dates equipment is changed or relocated (e.g., industrial surveys). Calibration verifications and quality control procedures must be repeated after any such changes before further testing begins.

Table 1. Daily calibration procedure

Video 1. Spirometer calibration

Hygiene, Infection Protection and Control

The goal of infection control is to prevent the transmission of infection to patients and staff during pulmonary function testing.
Infection can be transmitted by direct contact with surfaces such as mouthpieces, noseclips, handheld spirometers, chair arms, and immediate proximal surfaces of valves or tubing.
Indirect transmission occurs by aerosol droplets generated by the patient blowing into the equipment but also expelled into the air of the testing room between manoeuvers.

Pre procedure notes	Spirometry testing room should have adequate fresh air ventilation. Knowledge of the air changes per hour will inform the level of infection protection controls required for spirometry testing (as per local policy). HVAC and portable HEPA air cleaners may be used to boost fresh air changes. Check that patient symptoms for any possibility of transmission of infection. Postpone test if the patient is symptomatic e.g. influenza, RSV, COVID-19. Use of PPE is advised (facemask, gloves, eye-protection). Patients use surgical facemasks, practitioner should use a risk assessment prior to selecting suitable facemask for themselves i.e. FFP mask or surgical facemask). Mask fit testing and PPE training is advised. Hand hygiene is very important and must be performed by both the practitioner and patient before and after the test. Special attention to hand hygiene after touching surfaces and removal of PPE. Educate the patient on cough etiquette and removal/replacement of their surgical facemask during the test. Check for any mobility issues or if they require assistance with using their facemask or staying on the mouthpiece during the test. Consideration should be given to management of patients with special needs. Device must be clean prior to use for every patient. Refer to manufacturer instruction for cleaning of equipment Single use disposable Bacterial /viral filters must be used for all tests including when using disposable sensors Follow flow chart below for more detail
Patient factors	Extra precautions should be taken for patients with, or suspected of having, tuberculosis, hemoptysis, oral lesions, or other known transmissible infectious diseases. Some patients are known to harbour virulent bacteria in their airways:?Pseudomonas aeruginosa, or?Pseudomonas sepacia.?The equipment should be disinfected each time after use by such patients. The same holds for patients with tuberculosis in whom bacteria are demonstrable in their sputum. Immune-compromised patients, such as HIV-positives and patients treated with cytostatic drugs, should perform spirometry on instruments which have been disinfected immediately before the assessments. Patients with cystic fibrosis are similarly entitled to using a spirometer disinfected shortly before they are tested. Possible precautions include reserving equipment for the sole purpose of testing infected patients or testing such patients at the end of the workday to allow time for spirometer disassembly and disinfection and/or testing patients in their own rooms with adequate ventilation and appropriate protection for the operator.
Equipment factors	Manufacturers must explicitly describe acceptable methods of cleaning and disinfecting their equipment, including recommended chemicals and concentrations, as well as safety precautions for the operator. Local infection control requirements, especially for at-risk populations such as patients with cystic fibrosis, may supersede both manufacturers' recommendations.
Perform procedure	Source: McGowan A et al. International consensus on lung function testing during the COVID-19 pandemic and beyond. ERJ Open Research 2022 8(1): 00602-2021; DOI: 10.1183/23120541.00602-2021
Post procedure	In spirometry manoeuvres the patient not only expels air, but also saliva and/or sputum, debris. This contaminates the flow transducer of the spirometer and may cause it to malfunction. Use of single use filters will protect the sensors based on the bacterial and viral efficiency of the filter used. Nearly all flow transducers can be disassembled and should cleaned as per manufacturers instructions. All disposable items, including filters, mouthpieces, noseclips, PPE and gloves, must be disposed of at the end of the testing session. Room surfaces cleaning between patients should comply with local policy. Follow hand hygiene rules.