Priorto begins by installing the Spirometer and the Diffusion Workstation in a dedicated pulmonary function laboratory. The Spirometer uses a disposable flow transducer (pneumotach) with a range of 0–16 L/s and accuracy of ±3%. The Diffusion Workstation is configured for singlebreath carbon monoxide uptake (DLCO) measurement, with a gas mixture containing 0.3% CO, 0.3% CH₄ (methane), 21% O₂, balance N₂. Both systems are integrated with the laboratory’s EMR via HL7, automatically populating test requests and returning results.

The Spirometer’s flow transducer is calibrated daily using a 3 L calibration syringe; the system displays the calibration factor (target 1.00 ± 0.05). For FVC maneuvers, the system provides realtime flowvolume loops and automated acceptability criteria (exhalation time ≥6 seconds, backextrapolated volume <5% of FVC). The Spirometer generates a quality grade (A–F) for each maneuver based on ATS/ERS 2019 criteria. For pediatric patients, reference equations by Quanjer (2012) are preloaded.

The Diffusion Workstation’s gas analyzer is calibrated weekly using a reference gas with known CO and CH₄ concentrations. The singlebreath maneuver requires a breathhold of 10 seconds; the system’s automated timing starts when the patient’s lung volume reaches 90% of VC. The DLCO result is corrected for hemoglobin concentration; the technologist enters the patient’s most recent Hb value (within 30 days) into the workstation. For patients with interstitial lung disease, the system automatically calculates alveolar volume (VA) and DLCO/VA.

Technical Note: The Spirometer’s disposable flow transducer is singlepatient use; reuse will increase dead space and alter flow resistance. The Diffusion Workstation’s CO analyzer should be zeroed with medical air before each patient; a zero drift >0.01% CO invalidates the calibration.

Priorto installs the Body Plethysmograph (body box) in a temperaturecontrolled room (21–24°C, stable ±1°C). The plethysmograph is a constantvolume, variablepressure design with a 800 L capacity, accommodating patients up to 200 kg. The system measures thoracic gas volume (TGV) using panting maneuvers at 1 Hz, and airway resistance (Raw) using the occlusion method. The plethysmograph’s shutter is calibrated to close completely within 50 ms, verified monthly using a test lung.

The Body Plethysmograph’s pressure transducer has a range of ±20 cmH₂O with an accuracy of ±0.5 cmH₂O. The volume transducer (thermistorbased) measures flow at the mouthpiece, integrated to volume. For TGV measurement, the patient pants against a closed shutter; the system plots pressure versus volume loop, calculating TGV from the slope. Raw is derived from the same loop before shutter closure. The system automatically corrects for equipment dead space (50 mL for mouthpiece and filter).

The plethysmograph’s door is equipped with an emergency release that opens the box in less than 10 seconds. An intercom system allows twoway communication between the patient inside the box and the technologist. For claustrophobic patients, an openplethysmograph (nonenclosed) is available but provides lower accuracy for Raw measurement. The system’s volume calibration is performed daily using a 3 L syringe; pressure calibration uses a water manometer weekly.

Technical Note: The Body Plethysmograph’s temperature stability requirement is critical; a temperature change of 1°C during a 5minute test will cause TGV errors of 5%. The patient should be instructed to wear minimal clothing and remove metallic objects to avoid interference with the plethysmograph’s inductive sensors.

Priorto sets up the CPET System. This system includes three main parts. The first part is a metabolic cart for breath by breath analysis. The second part is an ECG gated cycle ergometer or treadmill. The third part is a patient monitoring module. This module covers 12 lead ECG, SpO2, and blood pressure.

The metabolic cart measures VO2, VCO2, and VE on every breath. It uses a turbine flow sensor and fast response oxygen and carbon dioxide analyzers. The oxygen analyzer uses zirconia technology. The carbon dioxide analyzer uses infrared technology. The system connects to the electronic medical record. It generates a structured report that includes the Wasserman 9 panel plot.

The CPET System’s breath by breath analyzer has a response time of less than 300 milliseconds. This has been validated with a square wave gas injection test.

The cycle ergometer is electrically braked. It uses a ramping protocol that can be set from 5 to 50 watts per minute. For patients with neuromuscular disease, the system uses a treadmill with handrail support.

The 12 lead ECG uses carbon fiber electrodes. This design reduces motion artifact. The system performs automated ST segment analysis every 15 seconds.

Quality control for the system includes daily gas calibration. This uses a reference mixture of 16 percent oxygen, 5 percent carbon dioxide, and the balance as nitrogen. Volume calibration is done with a 3 liter syringe at two flow rates. These rates are 0.5 liters per second and 2 liters per second.

The CPET protocol is chosen based on the patient’s estimated peak work rate in watts. This estimate comes from a pre test questionnaire.

The test stops when the patient reaches volitional exhaustion. This is defined as an RER value greater than 1.10. The test also stops if predefined safety criteria are met. These criteria include ST depression greater than 2 millimeters, arrhythmias, or SpO2 below 80 percent.

The final report includes VO2 peak, anaerobic threshold using the V slope method, and the VE by VCO2 slope.

Technical note: The turbine flow sensor in the breath by breath analyzer must be cleaned and dried after each test. Moisture buildup can cause underestimation of VE by up to 15 percent. The ramping protocol on the cycle ergometer should be customized for each patient. A generic ramp of 20 watts per minute may be too steep for elderly patients or those who are deconditioned.

Priorto installs a central pulmonary function data management system that aggregates results from the Spirometer, Diffusion Workstation, Body Plethysmograph, and CPET System. The system stores all raw traces (flowvolume loops, DLCO breathhold curves, CPET breathbybreath data) in a DICOMstructured format. A single signon interface allows technologists to launch any test from a common worklist. The system automatically applies Global Lung Function Initiative (GLI) 2012 reference equations for patients aged 3–95 years.

The central management system generates a unified report for each patient, including all tests performed on a given date. The report displays predicted values, percent predicted, zscores, and interpretation statements (e.g., “obstructive pattern with reduced DLCO”). For serial testing (e.g., before and after bronchodilator), the system calculates the percentage change and flags a significant response (FVC or FEV₁ increase >12% and >200 mL). The report is automatically transmitted to the referring physician’s EMR inbox.

Quality assurance features include automated grading of each test (A–F) and a weekly summary of unacceptable tests by technologist. For CPET, the system calculates the test’s “maximality” (peak heart rate vs. predicted, RER) and flags submaximal tests for physician review. The data management system is backed up daily to an offsite server, with a local redundant copy stored on a RAID 6 array.

Technical Note: The central data management system requires a dedicated SQL server with 16 GB RAM and 1 TB SSD storage; a 5year data retention policy requires additional storage for CPET raw traces (approximately 50 MB per test). The GLI reference equations are copyrighted; a valid license must be renewed annually.

Priorto implements a comprehensive safety and infection control protocol across all pulmonary function testing equipment. Each spirometer flow transducer is singlepatient use; after each test, the mouthpiece and bacterial filter (viral filtration efficiency >99.99%) are discarded. The Body Plethysmograph’s interior surfaces are disinfected with ultraviolet C (UVC) light for 10 minutes between patients. The CPET mouthpiece and breathing circuit are autoclavable (121°C for 15 minutes).

A pretest screening questionnaire identifies patients with active respiratory infections (fever, productive cough, known COVID19, tuberculosis). For these patients, testing is deferred or performed in a negativepressure room with N95 respirator worn by the technologist. The pulmonary lab’s ventilation system provides 15 air changes per hour, with exhaust directed outside the building. An emergency cart containing bronchodilators (albuterol), oxygen, and a bagvalve mask is stationed in the lab.

For patients at risk of bronchospasm (asthma, COPD), a baseline SpO₂ is recorded; the test is stopped if SpO₂ drops below 85% or if the patient reports chest tightness. The CPET system’s emergency stop button immediately halts the ergometer and opens the treadmill brake. A defibrillator is located within 30 seconds of the lab entrance. After each CPET, the metabolic cart’s sample line is purged with medical air for 60 seconds to clear residual gases.

Technical Note: The UVC lamp in the Body Plethysmograph should be replaced every 9,000 hours (approximately one year); a timer logs usage and displays a replacement warning. The viral bacterial filter has a maximum flow resistance of 0.5 cmH₂O at 12 L/s; higher resistance indicates saturation and requires replacement before the next test.