Evaluation the effect of breathing filters on end-tidal carbon dioxide during inferior abdominal surgery in infants and changes of tidal volume and respiratory rate needs for preventing of increasing end-tidal carbon dioxide.

Background: The aim of this study was to prevent of increasing end-tidal carbon dioxide (ETCO with changing of vital capacity and respiratory rate when using of birthing filter in infants.

Materials And Methods: In a randomized clinical trial study, ninety-four infant' patients were studied in three groups. Basic values, such as peak inspiratory pressure, tidal volume, minute ventilation, respiratory rate, and partial pressure of ET CO (PETCO) level had been evaluated after intubation, 10 min after intubation and 10 min after filter insertion. In the first group, patients only observed for changing in ETCO level. In the second and the third groups, respiratory rates and tidal volume had been increased retrospectively, until that ETCO ≤35 mmHg was received. We used ANOVA, Chi-square, and descriptive tests for data analysis. < 0.05 was considered statistically significant.

Results: Tidal volume 10 min after filter insertion was statistically higher in Group 3 (145.0 ± 26.3 ml) versus 129.3 ± 38.9 ml in Group 1 and 118.7 ± 20.8 ml in Group 2 ( = 0.02). Furthermore, respiratory rate at this time was statistically higher in Group 2 (25.82 ± 0.43) versus Groups 1 and 3 (21.05 ± 0.20 ml and 21.02 ± 0.60 ml, respectively) ( = 0.001). Minute volume and PETCO level were statistically significant between Group 1 and the other two groups after filter insertion ( = 0.01 and = 0.00,1 respectively).

Conclusion: With changing the vital capacity and respiratory rate we can control PETCO level ≤35 mmHg during using of birthing filters in infants. We recommend this instrument during anesthesia of infants.