The "worth" of routine spirometry in a cystic fibrosis clinic

Spirometry in Early Childhood in Cystic Fibrosis Patients

BACKGROUND

Spirometry data in cystic fibrosis (CF) patients in early childhood is scarce, and the ability of spirometry to detect airways obstruction is debatable.

OBJECTIVE

To evaluate the ability of spirometry to detect airflow obstruction in CF patients in early childhood.

METHODS

CF children (age range, 2.5 to 6.9 years) in stable clinical condition were recruited from five CF centers. The children performed guided spirometry (SpiroGame; patented by Dr. Vilzone, 2003). Spirometry indices were compared to values of a healthy early childhood population, and were analyzed with relation to age, gender, and clinical parameters (genotype, pancreatic status, and presence of Pseudomonas in sputum or oropharyngeal cultures).

RESULTS

Seventy-six of 93 children tested performed acceptable spirometry. FVC, FEV1, forced expiratory flow in 0.5 s (FEV0.5), and forced expiratory flow at 50% of vital capacity (FEF50) were significantly lower than healthy (z scores, mean +/- SD: - 0.36 +/- 0.58, - 0.36 +/- 0.72, - 1.20 +/- 0.87; and - 1.80 +/- 1.47, respectively; p < 0.01); z scores for FEV1 and FVC were similar over the age ranges studied. However, z scores for FEV0.5 and forced expiratory flow at 25 to 75% of vital capacity were significantly lower in older children compared to younger children (p < 0.001), and a higher proportion of 6-year-old than 3-year-old children had z scores that were > 2 SDs below the mean (65% vs 5%, p < 0.03). Girls demonstrated lower FEF50 than boys (z scores: - 2.42 +/- 1.91 vs - 1.56 +/- 1.23; p < 0.001). Clinical parameters evaluated were not found to influence spirometric indices.

CONCLUSIONS

Spirometry elicited by CF patients in early childhood can serve as an important noninvasive tool for monitoring pulmonary status. FEV0.5 and flow-related volumes might be more sensitive than the traditional FEV1 in detecting and portraying changes in lung function during early childhood.

Does carbon dioxide retention during exercise predict a more rapid decline in FEV1 in cystic fibrosis?

BACKGROUND

Carbon dioxide (CO2) retention during exercise is uncommon in mild to moderate lung disease in cystic fibrosis (CF). The ability to deal with increased CO2 is dependent on the degree of airflow limitation and inherent CO2 sensitivity. CO2 retention (CO2R) can be defined as a rise in P(ET)CO2 tension of > or =5 mm Hg with exercise together with a failure to reduce P(ET)CO2 tension after peak work by at least 3 mm Hg by the termination of exercise.

AIM

To ascertain if carbon dioxide retention during exercise is associated with more rapid decline in lung function.

METHODS

Annual spirometric and exercise data from 58 children aged 11-15 years, with moderate CF lung disease between 1996 and 2002 were analysed.

RESULTS

The mean FEV1 at baseline for the two groups was similar; the CO2R group (n = 15) was 62% and the non-CO2 retention group (CO2NR) was 64% (n = 43). The decline in FEV1 after 12 months was -3.2% (SD 1.1) in the CO2R group and -2.3% (SD 0.9) in the CO2NR group. The decline after 24 months was -6.3% (SD 1.3) and -1.8% (SD 1.1) respectively. After 36 months, the decline in FEV1 was -5.3% (SD 1.2) and -2.6% (SD 1.1) respectively. The overall decline in lung function was 14.8% (SD 2.1) in the CO2R group and 6.7% (SD 1.8) in the CO2NR group. Using the primary outcome measure as a decline in FEV(1) of >9%, final multivariate analysis showed that the relative risks for this model were (95% CIs in parentheses): DeltaP(ET)CO2 11.61 (3.41 to 24.12), peak VO2 1.23 (1.10 to 1.43), and initial FEV(1) 1.14 (1.02 to 1.28).

CONCLUSION

Results show that the inability to defend carbon dioxide during exercise is associated with a more rapid decline in lung function.

Assessing correlations between spirometry and Shwachman-Kulczycki score in children and adolescents

A retrospective observational study was carried out to analyze the correlations between formal pulmonary function tests and the Shwachman-Kulczycki (SK) score. Forty-six Brazilian cystic fibrosis (CF) patients, clinically stable, aged 7-19 years, were included. Clinical and radiological findings of the SK score system and spirometry variables were assessed by independent observers in a blinded manner. The strongest correlation (r = 0.75; 95% CI, 0.59-0.85; P < 0.001) was found for forced expiratory volume in 1 sec (FEV1). Despite some peculiarities of our patients, the results are in agreement with studies undertaken in industrialized countries, showing good correlation between FEV1 and SK score and its usefulness in managing CF. Accordingly, in countries where pulmonary function testing is not available, the SK score remains a valuable parameter on which to base treatment results.