5.1 Body Habitus, Sampling & Aerosol Equipment

Why ancillary equipment is scored under Domain I

On the NBRC PFT Examination (high cut = RPFT), Domain I — Instrumentation / Equipment includes more than spirometers and body boxes. Under I.A Setup, Maintain, and Calibrate, the Detailed Content Outline (DCO, effective October 2022) lists discrete equipment families you must be able to prepare for valid testing:

Sputum induction hardware is not a separate numbered Domain I item; the nebulizer that drives induction sits under I.A.4, and the filters/PPE it requires sit under I.A.18 (infection control materials / methods, section 5.3). Sputum sample collection itself is a Domain II procedure (II.5).

High-cut items often embed a wrong predicted value, a spoiled ABG, or an under-dosed challenge aerosol inside a “procedure” vignette. The first decision is frequently: was the device set up and maintained correctly? This section builds that equipment foundation; body-habitus measurement technique and blood-sampling procedure continue in later Domain II chapters.

Body habitus equipment (I.A.1)

Predicted spirometry, lung volumes, and DLCO depend on accurate height (and often weight, age, sex, and ethnicity per the reference set). The RPFT must keep the measuring tools accurate and ready—not just read a number from the EMR.

Stadiometer

A stadiometer (wall-mounted or freestanding height rod with a horizontal headpiece) is the preferred device for standing height:

• Level the base; verify the vertical scale is secure and readable.
• Headpiece should slide freely, lock, and contact the crown without tilting.
• Periodic checks against a certified length standard (or manufacturer protocol) detect bent rods and misaligned slides.
• Measure without shoes; patient stands upright, heels together, head in Frankfort plane when protocol requires it.

Exam trap: entering height from a clinic scale with a flimsy top arm, from patient report, or from a prior visit years ago introduces systematic predicted-value error. Domain I cares that you use a proper stadiometer and keep it functional.

Scale

A clinical scale (digital or beam) supports weight-dependent equations, BMI documentation, and some exercise or oxygen titration workflows:

• Zero/tare before use; confirm units (kg vs lb) match software expectations.
• Platform must be stable; battery/AC power checked on digital units.
• Wheelchair or bed scales are specialty alternatives when standing is impossible—know that the lab must have a documented pathway, not improvised estimates.

Calipers and secondary anthropometry

Skinfold or anthropometric calipers appear less often in routine PFT than stadiometer and scale, but body-composition or research protocols may require them. Maintain clean jaws, smooth action, and calibration against known thickness standards when the lab uses them. Document when secondary measures substitute for primary ones.

When standing height cannot be measured: arm span and ulnar length gear

When kyphosis, wheelchair dependence, amputation, or inability to stand prevents a valid stadiometer reading, labs use alternative height estimates. Equipment readiness matters:

Key equipment principle: alternative methods are only as good as the tape/caliper accuracy, landmark consistency, and correct equation selection in software. Never “eyeball” height. Flag estimated height in the record so interpreters know predicted values rest on a surrogate.

Blood sample collection equipment (I.A.16)

Arterial and capillary blood gas / co-oximetry workflows require collection gear that preserves gas tensions and avoids pre-analytical error. Domain I focuses on having and preparing the right tools; puncture technique is Domain II.

Arterial collection set

Typical arterial blood gas (ABG) kit components:

• Syringe: self-filling or low-resistance arterial syringe, usually pre-heparinized with lyophilized or liquid lithium heparin (or equivalent) matched to sample volume—excess liquid heparin dilutes PCO2 and can bias electrolytes if co-analyzed.
• Needles: appropriate gauge (often 22–25 G for radial) and length; safety-engineered sharps preferred; spare needles available.
• Site prep: antiseptic swabs (alcohol or facility-approved), gauze, adhesive bandage, optional local anesthetic per policy.
• Needle safety: sharps container at point of care; never recap used needles with a two-handed technique.
• Transport: ice-water slurry (not dry ice) when analysis will be delayed beyond lab policy (commonly when delay exceeds ~15–30 minutes—follow manufacturer and CLSI/lab SOP). Ice slows metabolism that consumes O2 and produces CO2 in the syringe.
• Mixing: air bubbles expelled promptly; gentle mixing so heparin contacts the full sample without frothing.

Capillary and related devices

When arterial puncture is contraindicated or for neonates/pediatrics:

• Capillary tubes or collection devices designed for blood gas (heparinized),
• Lancets of appropriate depth,
• Warming devices or warm cloths for arterialization of the puncture site when protocol requires,
• Sealant clay or caps to close tubes without introducing air.

Venous samples for some analytes use standard phlebotomy tubes, but true arterial blood gas interpretation requires arterial (or properly arterialized capillary) samples—know which tubes and anticoagulants your analyzer accepts.

Setup checklist mindset: stocked kits, in-date heparin syringes, functioning ice slurry ready before the stick, labeled containers, and a clear path to the analyzer. Missing ice or an expired syringe is an equipment failure before the needle ever touches skin.

Aerosol delivery equipment (I.A.4) and inhalers (I.A.5)

PFT labs deliver aerosols for bronchodilator response, bronchial provocation (e.g., methacholine, mannitol, exercise-related pathways), and sometimes sputum induction. Domain I expects familiarity with device types and dose-control hardware under I.A.4 (nebulizers, dosimeters) and I.A.5 (MDI/DPI).

Jet and ultrasonic nebulizers

Small-volume jet nebulizers use compressed air or oxygen to aerosolize liquid medication or challenge agent. Setup includes:

• Correct gas source and flow (often 6–8 L/min for many SVNs—follow device and drug protocol),
• Intact nebulizer cup, baffle, T-piece, mouthpiece or mask,
• Filters on the expiratory limb when scavenging or infection control requires them,
• Cleaning/disinfection or single-patient disposable cups per policy.

Ultrasonic nebulizers use a vibrating crystal; they can produce dense aerosols useful for some induction protocols but are less common for precise methacholine dosing than calibrated jet systems or dosimeters.

Dosimeters

A dosimeter (breath-actuated or timed) delivers a quantified aerosol dose per actuation or inhalation—critical for standardized methacholine challenge (e.g., five-breath or dosimeter methods per ATS/ERS-style protocols). RPFT-level setup includes:

• Verified nebulizer output / calibration of dose delivery per lab QC schedule,
• Correct diluent and agent concentrations staged in labeled syringes or cups,
• Trigger sensitivity and breath-count settings matching the written protocol,
• Backup nebulizer and clean circuits ready between concentration steps when required.

Exam focus: if challenge results look odd, ask whether the dosimeter/nebulizer output was verified—not only whether the patient inhaled “hard enough.”

MDI and DPI devices in the lab

For bronchodilator response testing and teaching:

Stock common lab agents (e.g., albuterol MDI) with spacers, and know which studies use nebulized vs inhaled-device routes. Document dose, device, and time so post-BD comparisons are interpretable.

Sputum induction equipment (I.A.4 nebulizer + I.A.18 infection control)

Sputum induction generates lower-airway secretions with inhaled hypertonic (or isotonic) saline aerosol, often for cytology, infection workups, or research. Equipment typically includes:

• Ultrasonic or jet nebulizer capable of sustained saline aerosol,
• Sterile saline of specified concentration (e.g., 3%, 4%, 5% stepwise protocols),
• Oxygen or air blender and flowmeter as required,
• Mouthpiece/mask circuit with exhalation filters when indicated,
• Specimen cups, ice for samples when ordered,
• Pulse oximeter and bronchodilator available (induction can provoke bronchospasm—link to monitoring equipment in 5.2),
• PPE and room ventilation planning (aerosol-generating procedure).

Infection-control overlap: induction is an aerosol-generating procedure. Bacterial/viral filters, staff PPE, and airborne precautions for suspected TB or other pathogens are inseparable from “having the induction machine ready.” Details expand in section 5.3; for I.A.18, know that filters, disposable circuits, and cleaning SOPs are part of the equipment package, not optional extras.

Integrated setup workflow (exam mental model)

Before a complex session that might include anthropometrics, BD response, challenge, ABG, or induction:

1. Habitus gear: stadiometer and scale checked; tape available for arm span/ulna if needed.
2. Collection gear: ABG syringes, needles, ice slurry, labels, sharps container.
3. Aerosol gear: MDI + spacer and/or nebulizer/dosimeter calibrated and stocked with agents and diluents.
4. Induction gear (if ordered): saline, nebulizer, filters, oximeter, rescue BD, specimen containers.
5. Infection control: filters, wipes, PPE staged (see 5.3).

If any of these fail, the “procedure” never becomes valid data. That is why NBRC places these tools under Domain I alongside the big analyzers—and why RPFT candidates must treat ancillary equipment with the same rigor as a body box.