Histamine provocation in young, awake children with bronchial asthma, using a fall in oxygenation as the only indicator of a bronchial reaction

The aim of the present study was to determine the relationship between bronchodilator response, assessed by interrupter resistance (Rint), and bronchial reactivity in preschool children with chronic cough. Thirty-eight children coughers (median age 5.0 years, range 2.8-6.4) were tested. Bronchodilator response was recorded within 4 months before methacholine challenge. Response to the latter was assessed using transcutaneous partial pressure of oxygen and Rint. Children were considered responders if a 20% fall in transcutaneous partial pressure of oxygen occurred during the bronchial challenge. Bronchodilator response was not different between responders (n = 24) and nonresponders (n = 14) [median (range) -0.11 (-0.44-0.09) vs. -0.08 (-0.21-0.10) kPa L(-1) sec; respectively]. However, none of the nonresponders had a bronchodilator response larger than -0.21 kPa L(-1) sec, this cutoff had a 100% positive and a 44% negative predictive value to predict a positive methacholine challenge. The relationship between bronchodilator response and bronchial methacholine responsiveness reached the limit of significance (P = 0.048). Furthermore, the magnitude of the bronchodilator response was correlated to the level of methacholine-induced level of bronchoconstriction (P = 0.01), and to the postchallenge bronchodilation (P = 0.04), all values expressed as % predicted. Moreover, the postbronchodilator Rint value obtained with preceding methacholine challenge was lower than the postbronchodilator value without preceding methacholine challenge in 71.4% (10/14) of the nonresponders and in only 33.3% (8/24) of the responders. Conclusions in preschool coughers bronchodilator response, assessed by the interrupter technique, was correlated to the bronchial responsiveness to methacholine. Non responders had a bronchodilator response not larger than -0.21 kPa L(-1) sec.

Section: Relationship Between Bronchodilator Response and Bronchial Rmentioning

confidence: 98%

Can bronchodilator response predict bronchial response to methacholine in preschool coughers?

Beydon

Mbuila

Peiffer

et al. 2008

Repeated blood gas monitoring in healthy children and adolescents by the transcutaneous route

Lagerkvist

Sten

Redfors

et al. 2003

The aim of the study was to establish transcutaneous oxygen tension (tcPO(2)), carbon dioxide tension (tcPCO(2)), and oxygen saturation (tcSO(2)) values and to investigate the intra- and interindividual variation in these values in healthy children and adolescents. Forty-one healthy children/adolescents (21 girls; mean age, 12.1 years; SD, 3.5; range, 5.0-19.0 years) participated. Continuous recordings of tcPO(2), tcPCO(2), tcSO(2), and heart rate (HR) were made for 30 min on two occasions, with a mean interval of 10.3 days, with the child/adolescent in a sitting position. The respiratory rate (RR) was counted manually during the last 5 min of each recording. The mean values of tcPO(2), tcPCO(2), tcSO(2), HR, and RR during the last 5 min of the recordings were reported. At the first recording, the mean value for tcPO(2) was 10.8 kPa (SD 1.0), for tcPCO(2) 5.1 kPa (0.4), for tcSO(2) 97.4% (1.1), for HR 82.2 min(-1) (9.9), and for RR 19.0 min(-1) (2.8). The coefficient of variation for tcPO(2) was 9.3%, for tcPCO(2) 7.8%, for tcSO(2) 1.1%, for HR 12.0%, and for RR 14.7%. The mean intraindividual variation in tcPO(2) was 0.3 kPa (SD 1.0), tcPCO(2) 0.0 kPa (0.5), tcSO(2) 0.1% (1.3), HR 0.1 min(-1) (7.7), and RR 0.5 min(-1) (2.7). No significant differences were observed in tcPO(2), tcPCO(2), tcSO(2), HR, or RR between the two recordings. In conclusion, the reproducibility of tcPO(2), tcPCO(2), and tcSO(2) monitoring during 30 min in healthy children and adolescents was good. This indicates that transcutaneous blood gas monitoring may be used to document significant changes in blood gas tensions and oxygen saturation over time.

Measurements of resistance by the interrupter technique and of transcutaneous partial pressure of oxygen in young children during methacholine challenge

Beydon

Trang-Pham

Bernard

et al. 2001

Measurement of bronchial airway responsiveness requires noninvasive techniques in young children. The study was designed to examine the changes in resistance as measured using the interrupter technique (Rint) at the dose of methacholine (M) that induced a fall in transcutaneous partial pressure in O2 (P(tc)O2) > or = 20% (PD(20)P(tc)O2) in young children. Rint was calculated using the linear back-extrapolation method (Rint(L)) and the end-interrupter method (Rint(EI)). Twenty-two children (mean age, 5.2 +/- 1.1 years; range, 3.4 - 7.1 years) with nonspecific respiratory symptoms (mainly chronic cough, n = 17) were tested. P(tc)O2, Rint(L), and Rint(EI) were measured before the test, after saline challenge (baseline (B)), after each dose of M delivered by a dosimeter, and after bronchodilator (BD) inhalation. P(tc)O2 decreased significantly during M challenge, from 85 +/- 6 mmHg (B) to 62 +/- 9 mmHg (P < 0.05), and increased after BD inhalation, to 82 +/- 8 mmHg. Rint(L) and Rint(EI) increased significantly during M challenge, from 0.94 +/- 0.2 KPa/L/s and 1.11 +/- 0.19 KPa/L/s (B) to 1.27 +/- 0.35 KPa/L/s and 1.47 +/- 0.37 KPa/L/s, respectively (P < 0.05), and decreased after BD inhalation to 0.80 +/- 0.17 KPa/L/s and 0.95 +/- 0.18 KPa/L/s, respectively. Nineteen of 22 children reached the PD(20)P(tc)O2 at a dose of M ranging from 50-400 microg. At the PD(20)P(tc)O2, significant changes in Rint(L) and Rint(EI) (sensitivity index (SI) > or = 2) were found in 79% and 63% of children, respectively. We conclude that: 1) M challenge using P(tc)O2 is safe in young children; and 2) our findings are not in favor of the use of Rint as the only indicator of bronchial reaction in young children during M challenge.