NIOSH SSS common mistakes
NIOSH SSS · Understand the traps and how to avoid them.
Treating a recent uncomplicated myocardial infarction, unstable angina, or a recent pneumothorax as automatic hard stops without weighing urgency, while simultaneously missing that a resting SpO2 below the acceptable threshold or an acute illness warrants postponement.
Candidates memorize a single 'absolute contraindication' list and apply it rigidly; they forget that most contraindications are relative and depend on whether the result will change management, and they overlook physiologic readiness screening (vitals, oxygen saturation, ability to sit upright).
What to do instead
Frame contraindications as relative versus absolute and justify each decision by risk of harm versus value of the result. Practice classifying scenarios: recent MI, thoracic or abdominal surgery, hemoptysis of unknown origin, pneumothorax, unstable cardiovascular status, aneurysm, recent eye or ear surgery, acute illness, and poor cooperation. Always state that the supervising clinician decides when a relative contraindication is outweighed by need.
Describing calibration verification as 'calibrating the machine' and failing to distinguish a daily calibration check with a 3-L syringe from a full calibration adjustment, and not stating the accuracy tolerance for the syringe check.
The terms calibration, calibration verification, and quality control are used loosely in training materials, and candidates never anchor a numeric tolerance to the check, so they cannot answer a question that asks whether a given measured volume passes.
What to do instead
Memorize the operational sequence: perform a calibration verification at the start of each testing day and after cleaning, maintenance, or any event that could affect the sensor; a 3-L syringe discharge must read within 3.5% of the delivered volume (roughly 2.895 to 3.105 L) at multiple flows; record the result. Reserve 'calibration' for adjusting the device to a reference. Be able to state what to do when the check fails: do not test patients until it passes.
Skipping or rushing the pre-test interview and instead moving straight to the maneuver, so height, age, sex, and ethnicity used for reference values are guessed, and recent smoking, bronchodilator use, or acute symptoms are never documented.
Candidates focus their study time on the blow itself and treat preparation as clerical; under time pressure they accept a stated height without measuring and omit the medication and smoking timeline.
What to do instead
Adopt a fixed checklist: verify identity, measure standing height without shoes, record age, sex, and race/ethnicity as required by the chosen reference set, document smoking status and time since last cigarette, record all bronchodilator and other relevant medications with timing, screen for contraindications and for conditions that affect the maneuver, confirm the patient can sit upright and has no tight clothing, and explain the test and its risks. State that the predicted values depend on these inputs, so an error here corrupts every downstream number.
Giving coaching that is vague or purely verbal ('take a big breath and blow hard') without demonstrating, without using a forceful count, and without specific corrective cues when the effort is submaximal.
Candidates are uncomfortable being loud and directive, or they have never practiced the specific cue for each failure pattern, so they default to polite encouragement that does not produce a maximal effort.
What to do instead
Learn a demonstration-plus-cue script: show the maneuver, then give a rapid verbal push ('blow, blow, blow, keep going, keep going'), use a count of at least six seconds, and match the cue to the defect, for example 'blast it out faster' for a slow start, 'keep pushing, don't stop' for early termination, and 'seal your lips, don't let air escape' for a leak. Practice coaching aloud until the timing and intensity are automatic, and be able to describe how coaching differs for a child or an elderly participant.
Judging acceptability from the flow-volume or volume-time display alone, or accepting a maneuver because the numbers 'look reasonable', without applying the end-of-test and start-of-test criteria explicitly.
Candidates conflate acceptability with reproducibility and never internalize the specific criteria, so they cannot articulate why a curve with a good FEV1 but a 4-second exhalation is unacceptable.
What to do instead
State the acceptability criteria as a checklist for each maneuver: free of artifacts such as cough in the first second, glottic closure, leak, or obstruction of the mouthpiece; good start with a rapid rise to peak flow and an extrapolated volume within tolerance; satisfactory exhalation that is not terminated early, with a plateau in the volume-time curve and exhalation of at least six seconds (or until a plateau in a child); and no evidence of a second breath. Then apply the reproducibility criteria separately to the best two acceptable efforts.
Misapplying reproducibility criteria by comparing the wrong pair of efforts, or declaring a session complete after two efforts that are not the best two acceptable maneuvers, and not knowing when to stop testing.
Candidates memorize the numeric thresholds but not the rule that they apply only to the two largest acceptable FEV1 and FVC values, and they confuse the maximum number of efforts with the minimum required.
What to do instead
State the rule precisely: after at least three acceptable maneuvers, the two largest FEV1 values and the two largest FVC values must each agree within 150 mL (or 100 mL in some protocols); if not, continue testing up to a maximum of eight efforts, and stop earlier if the participant cannot continue or is exhausted. Report the largest FEV1 and the largest FVC from acceptable maneuvers, and be able to explain why the largest values may come from different curves.
Reporting a percent predicted without stating which reference equation was used, or interpreting a borderline ratio without applying the appropriate lower limit of normal and the post-bronchodilator comparison.
Candidates learn the fixed 0.70 ratio and the general shape of obstructive and restrictive patterns but not the concept of the fifth percentile lower limit of normal, the effect of age on the ratio, or the requirement to compare pre- and post-bronchodilator values.
What to do instead
Practice a structured interpretation: identify the reference set and state it, compare FEV1/FVC to the lower limit of normal rather than a fixed cutoff, then use FVC to separate obstruction from restriction and note that a low FVC with a preserved ratio suggests restriction only when confirmed by lung volumes. Describe the bronchodilator response in absolute and percent terms and state the threshold used. Be able to name the pattern for a mixed defect and to flag when test quality limits interpretation.
Producing a report that lists raw numbers without the quality grade, the number of acceptable maneuvers, or a plain-language summary, and omitting the technologist's comments about limited effort.
Candidates treat reporting as data entry and do not realize that a result without a quality statement can be clinically misleading, especially when the best effort was submaximal.
What to do instead
Build a reporting template that always includes participant identifiers, measured height and demographic inputs, the reference set, pre- and post-bronchodilator values with percent predicted and lower limit of normal, the number of acceptable maneuvers and the reproducibility achieved, an overall quality grade, and a short interpretive comment. Practice writing a two-sentence summary a non-specialist clinician can act on, and practice explaining the same result to the participant without overstating certainty.
Describing infection control as 'wipe the mouthpiece' and missing the hierarchy of barriers, hand hygiene, single-use items, and the distinction between cleaning, disinfection, and sterilization for reusable spirometer components.
Candidates reduce infection control to a single step they remember from a poster, and they have not thought about which parts contact mucous membranes versus intact skin or about handling of the device between participants.
What to do instead
State a layered routine: hand hygiene before and after every participant, gloves when contact with secretions is likely, a new single-use mouthpiece or filter for each participant, disinfection of reusable surfaces and sensors per manufacturer instructions with the correct contact time, safe disposal of consumables, and separation of clean and contaminated items. Be able to explain why a filter does not replace cleaning of the device and when a spirometer must be taken out of service.
Believing that a spirometer's internal quality-control software or a manufacturer's calibration certificate removes the need for documented daily checks and periodic biologic control testing.
Candidates assume modern devices self-verify, and they have not learned that quality control includes a documented record of calibration verification, biologic controls with a healthy nonsmoker, and review of results over time.
What to do instead
Describe a written quality-control program: daily calibration verification with a 3-L syringe before testing, periodic biologic control testing with a healthy nonsmoker whose values are tracked on a control chart with defined limits, regular review of the log, and corrective action and documentation when results drift. Be able to say what a shift on the control chart implies and why the records matter for both patient safety and accreditation.