Chest
Volume 102, Issue 3, September 1992, Pages 753-758
Journal home page for Chest

Clinical Investigations
Distilled Water Challenges in Asthmatic Children: Comparison of Different Protocols

https://doi.org/10.1378/chest.102.3.753Get rights and content

Inhalation of ultrasonically nebulized distilled water (UNDW) appears a promising candidate for routine challenge testing in bronchial asthma. We have compared two different methods of application of UNDW in 12 asthmatic children with a positive response to methacholine provocation (MCh), in an attempt to increase UNDW sensitivity and to establish standard testing protocols. In addition, results from UNDW challenges were compared to responses to inhalation of jet-nebulized distilled water (JNDW) and cold air (CACh). Compared to MCh, the sensitivity of continuously or intermittently (iUNDW) inhaled UNDW was 67 percent or 75 percent, respectively, when a positive response was defined by a ≥20 percent fall in FEV1, but was higher when definition of a positive response was based on results from flow volume curves. Sensitivity of continuous or intermittent inhalation of JNDW was lower than for UNDW. The UNDW inhalations were better tolerated than CACh. Following stepwise iUNDW challenge, there was a clear reaction plateau for all variables measured. Results indicate that testing protocols with iUNDW inhalations over 6 to 10 min (corresponding to 7 to 11 ml water inhalation) yield the maximum sensitivity attainable with UNDW challenges, and require a minimum of patient and investigator effort.

Section snippets

Subjects

Fifteen asthmatic patients, eight girls and seven boys, aged 11.5 ± 2.9 years (mean ± SD; range: 7.75 to 17 years) with positive results from MCh entered the study. All patients had asthma previously diagnosed by a physician and gave a history of episodic dyspnea, wheezing, and coughing. Asthma was precipitated by exercise in six patients, by exposure to known allergens in four patients, and by cold, foggy weather in three patients. Standardized skin prick testing, radioallergosorbent tests

Results

Twelve patients completed the six different challenges, and none developed symptoms or signs of respiratory distress. The challenges were well tolerated except for a mild cough at the beginning of UNDW inhalations. Three patients had to be excluded because of inability to hyperventilate as required for CACh (two patients) or for lack of compliance (one patient).

Baseline results from PFTs and maximum responses of PF to challenge tests are summarized in Table 1. There were no significant

Discussion

In our study, MCh was used as the criterion standard for measuring nonspecific bronchial hyperresponsiveness in asthmatic children. Against this standard, the sensitivity of cUNDW was 67 percent and that of iUNDW was 75 percent. This is in broad agreement with other authors who reported sensitivities of between 52 and 68 percent for iUNDW challenge.4, 5, 9 In contrast, Anderson et al3 found an iUNDW sensitivity of 100 percent. We have no ready explanation for the discrepancy between the latter

ACKNOWLEDGMENT

We thank Brigitte Pomianek and Marianne Koller for their technical assistance, and H. Herkner, Ph.D., for the PRIST and RAST studies.

References (31)

  • B Bascom et al.

    Bronchoconstriction induced by distilled water: sensitivity in asthmatics and relationship to exercise-induced bronchospasm

    Am Rev Respir Dis

    (1986)
  • AB DuBois et al.

    A new method for measuring airway resistance in man using a body plethysmograph: values in normal subjects and in patients with respiratory disease

    J Clin Invest

    (1956)
  • A Zapletal et al.

    Lung function in children and adolescents: methods, reference values

  • M Zach et al.

    Cold air challenge of airway hyperreactivity in children: practical application and theoretical aspects

    Pediatr Res

    (1984)
  • DJ Hill et al.

    Asthma: the physiological and clinical spectrum in childhood: respiratory function studies in its assessment

    Arch Dis Child

    (1972)
  • Cited by (6)

    Manuscript received October 31; revision accepted January 24.

    View full text