Guide to Conducting the DLCO Test

Introduction

The DLCO (Diffusing Capacity of the Lungs for Carbon Monoxide) test is used to measure the efficiency of gas exchange between the lungs and the blood.

DLCO Test Procedure

Setup and Calibration

• Equipment Preparation:
  • Select the DLCO icon on the equipment.
  • Enter patient's hemoglobin and/or carboxyhemoglobin levels via 'Manual Entry' and 'Blood'.
  • Insert umbilical into the calibration port.
  • Select 'Gas Calibration' and wait for calibration to complete.

Patient Preparation and Testing

• Attach and Connect:
  • Attach umbilical clip to flow sensor.
  • Connect flow sensor to patient circuit.
• Begin Test:
  • Select 'Start'.
  • Patient instructions:
    • Insert mouthpiece tightly and breathe normally for four breaths.
    • After the fourth breath, inhale slightly, exhale totally to residual volume, inhale smoothly to lung capacity, hold for 10 seconds, then exhale completely.

Monitoring

• Gauge Indicators:
  • Top of gauge turns green at 90% vital capacity inhalation.
  • Bottom of gauge turns green within correct flow range.
  • Center shows mouth pressure; ensure it is within user-adjustable limits.

Quality Control

• Quality Graph Displays:
  • Percent of vital capacity.
  • Breath hold time.
  • Inspiratory/expiratory time.

Repeat Test (if Necessary)

• Recalibration and Repetition:
  • Insert umbilical into calibration port and select 'Gas Calibration'.
  • Repeat test if needed and check if repeatability criteria are met.
  • Scorecard will display compliance with ATS and ERS standards.

Conclusion

The DLCO test is crucial for assessing pulmonary gas exchange efficiency and should be conducted following the precise procedural steps to ensure accurate and reliable results.