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Correspondence  |   October 1999
Cost-efficient End-tidal Carbon Dioxide Monitoring via Hudson-style Mask 
Author Notes
  • Associate Professor
  • Department of Anesthesiology
  • University of Pittsburgh School of Medicine
  • Montefiore University Hospital
  • Pittsburgh, Pennsylvania 15213
Article Information
Correspondence
Correspondence   |   October 1999
Cost-efficient End-tidal Carbon Dioxide Monitoring via Hudson-style Mask 
Anesthesiology 10 1999, Vol.91, 1176. doi:
Anesthesiology 10 1999, Vol.91, 1176. doi:
To the Editor:—
End-tidal carbon dioxide (ETCO2) monitoring during spontaneous respiration is desirable. 1 I had been previously using intravenous cannulae to attach carbon dioxide monitoring tubing to Hudson-style masks during cases involving intravenous sedation. The cannula cost $.53 and required scissors to cut off the excessive lengths, which protruded into the masks and “tickled” noses. Recently, the Intertech Gas sampling lines (order No. 225–3421–800; Smith Industries Medical Systems, Fort Meyers, FL) have become standard in our operating rooms (fig. 1
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
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). These lines have Luer-lock hubs with an internal 4-mm long and 4-mm diameter “male” protrusion. The hub can be twisted into and quickly secured within a vent hole of standard Hudson-style (Hudson Respiratory Care, Temecula, CA) oxygen masks when counterpressure is applied from inside the mask. In this way, the additional costs are eliminated to secure carbon dioxide monitoring devices onto standard masks as is the need to carry scissors to trim intravenous catheters. I recommend this method, which allows inexpensive and hygienic ETCO2sampling, directly at the site of expired gas egress. Because the Hudson mask collects expired gases from both the mouth and the nose, this type of monitoring device is very effective in detecting carbon dioxide, irrespective of whether “mouth” or “nose” breathers are encountered. I also recommend looping the carbon dioxide sampling line under the Hudson mask strap to prevent inadvertent dislodgement of the line from the Hudson mask via  incidental traction on the sampling line. This facilitates secure intraoperative placement and rapid removal at the end of the case.
Reference 
Reference 
Lake CL: Monitoring: History and philosophy, Clinical Monitoring for Anesthesia and Critical Care, 2nd edition. Edited by Lake C. Philadelphia, WB Saunders, 1994 pp 2–10
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
Fig. 1. The gas analysis line is shown in place on the Hudson mask on the mannequin. The 4-mm “male” protrusion is also shown (  arrow  ) on separate tubing. 
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