| 11 th Annual Pediatric Critical Care Colloquium |
| Session/Time | Pulmonary II/Thu, 2:00 - 4: 00 PM |
| Title | Effect of Exhalation Flow Rates and Inline Versus Bag Sampling on Pulmonary Exhaled Nitric Oxide in Children with Asthma |
| Author | Kissoon, P Silkoff, S Murphy, L Duckworth, C Taylor |
| Affiliation | Wolfson Children's Hospital, Jacksonville, FL and Univ. of Colorado, Denver, CO |
| Introduction | Pulmonary exhaled nitric oxide (ENO) is a marker of endobronchial inflammation. ENO levels are increased in asthmatics and may be used to diagnose asthma, assess disease severity and guide steroid and arginine analogs dosing. However, comparison of ENO values from different laboratories is not possible since the sampling techniques are not standardized. We evaluated the effects of varying exhalation flow rates and collection technique on ENO values. |
| Method | Eleven children (I 0-1 5 -years, mean 12.4 years) with asthma were studied (mild to moderate restrictive disease( FEV, > 50% predicted). ENO measurements in triplicate were obtained inline using a Sievers Model 280 Chemiluminescence Analyzer and by collecting exhaled breath simultaneously in mylar bags for analysis within 2 hours. Exhalation was done against an end expiratory pressure of > I Ocm H20 to ensure vellum closure and eliminate nasal NO contamination. ENO values at 4 different flow rates (46, 31, 23 and 15mls/sec) obtained by using resistors in the circuit. ENO values in parts per billion (ppb) are presented as mean i standard deviation. Differences (p <05) for NO were sought between bag and inline collection methods and flow rates using t-test and Pearson correlation coefficients. < .05) for NO were sought between bag and inline collection methods and flow rates using t-test and Pearson correlation coefficients. |
| Result | The 3 samples at each flow rate varied <5%, ( r=".99" ). ENO values increased as flow rated decreased ( 53 ± 38 ppb at 46misisec to 109 + 80 at 15mis/sec) for inline measurements and ( 47 + 24 ppb at 46mis/sec and 72 + 39 ppb at mls/sec) for bag collections. lnfine values for ENO were significantly different for each il.ow rate (p < .05). There wqs a good correlation between inline and bag ccllet,-,tion techniques at each flo i i-ate ( r>< 5%, (r= .99, p = .002). ENO values increased as flow rated decreased ( 53 ± 38 ppb at 46misisec to 109 + 80 at 15mis/sec) for inline measurements and ( 47 + 24 ppb at 46mis/sec and 72 + 39 ppb at mls/sec) for bag collections. lnfine values for ENO were significantly different for each il.ow rate (p < .05). There wqs a good correlation between inline and bag collection techniques at each flow rate (r> .99, p = .002)However, bag sampling values were consistently lower than in line values. |
| Conclusion | ENO measurements using infine and bag collection techniques are practical in children with asthma. The flow rates used in this study provide optimal signal amplification with <5% variations in ENO values. ENO values using higher flows and bag collections are consistently lower than values obtained by inline sampling. EINO values should be interpreted in relationship to exhalation rates and methods (inline versus bag collection) ci' gas sampling. asthma. The flow rates used in this study provide optimal signal amplification with <5% variations in ENO values. ENO values using higher flows and bag collections are consistently lower than values obtained by inline sampling. EINO values should be interpreted in relationship to exhalation rates and methods (inline vs. bag collection) of gas sampling. |
Use your browser's back button to return to the appropriate index of abstracts...
Back to PCCC 98 Abstract Introduction | Back to PCCC 1998