The Science Journal of the American Association for Respiratory Care

2007 OPEN FORUM Abstracts

PERFORMANCE AND CLINICAL EFFICACY OF EXTENDED LENGTH NASAL CANNULA TUBING IN CONJUNCTION WITH A PULSE DOSE OXYGEN DELIVERY DEVICE

J. P. Stegmaier1, R. L. Chatburn2


Background: Pulse dose oxygen delivery (PDOD) devices are considered a standard of practice in the delivery of long term oxygen therapy (LTOT) in the home. PDOD devices deliver a volume (bolus) of oxygen with each breath, operating in many ways like a simple volume ventilator. PDOD device performance is usually specified for use with a standard nasal cannula (NC) length of 7 ft. Our hypothesis was that increasing the NC tubing length will alter the bolus delivery characteristics and potentially diminish the clinical efficacy in some patients, which can be corrected through simple titration.
Materials: Inogen One (Inogen, Inc) portable oxygen concentrator (POC), standard NC with 7 ft of tubing (Salter Labs), 21 ft oxygen extension tubing (Invacare, Inc), and pulse oximeter (BCI).

Method: 19 patients (11 female, 8 male) mean age 71, currently prescribed home LTOT of ≤3 L/min were evaluated. Physician orders were obtained for titration with the POC to a target SpO2 ≥90% during all activities using the 7 ft and 28 ft NC. Patients were titrated to the POC at rest and during a 3 minute walk (activity) on a 7 ft NC (baseline). Following the baseline titration, 21 ft of oxygen extension tubing was added to produce a total tubing length of 28 ft. The titration procedure was repeated both at rest and with activity. In the event the patient’s SpO2 fell below 90%, the POC setting was titrated until the SpO2 reached ≥90% at rest and with activity. Median values for were compared with the Wilcoxon Signed Rank Test with p < 0.05 considered significant.

Results: All patients tolerated and completed the study. Mean (standard deviation) results are shown in the table. The addition of 21 ft of NC extension tubing (no additional titration) produced a modest drop in mean SpO2 at rest (p < 0.001), which was exaggerated with activity (p < 0.001) before any additional titration. Titration to the 28 ft length produced SpO2 values comparable to baseline even at activity (p = 0.07).

Conclusion: The results support the hypothesis that when appropriately titrated, a PDOD used with a POC can provide adequate oxygen delivery with tubing lengths up to 28 feet.

Test POC Setting SpO2 Rest (%) SpO2 Activity (%)
7 ft cannula baseline 2 (0.6) 92 (1.3) 92 (1.1)
28 ft cannula no additional titration n/a 91 (1.8) 89 (1.1)
28 ft cannula titrated 3 (1.0) 92 (1.3) 91 (0.9

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