C. F. Robertson

Subjective scoring of cough in children: parent-completed vs child-completed diary cards vs an objective method

Cough is often used as an outcome measure, although the reporting of cough is unreliable. Using a 24 h ambulatory cough meter to measure cough frequency, the aim of this study was to compare: 1) the correlation of child-completed diary cards to the objective measurement, with that of parent-completed diary cards; and 2) the visual analogue scale (VAS) to the verbal category descriptive (VCD) score. The cough meter consisted of a previously validated Holter monitor and a cough processor. Eighty four children (39 with recurrent cough and 45 controls, aged 6-17 yrs) used a cough meter at least once. Thirty three subjects used the cough meter twice. Parents and children completed separate diary cards using the VAS and VCD scores. The strength of the relationship between the subjective scores and the objective recordings was analysed by spearmans rank correlation coefficient. For daytime cough, child-completed diary cards and the VCD correlated better to the objective measurement than parent-completed diary cards and the VAS, respectively. In subjects that used the cough meter twice, the difference between the cough frequency correlated to the difference in the subjective scores. The confidence intervals for the correlation coefficients were wide. The agreement between the objective and subjective presence of daytime cough was good but that for night-time cough was poor. We conclude that the severity of cough defined on diary cards may not represent cough frequency. Objective readings are first choice but currently not yet practical. The verbal category descriptive diary card completed by children and assisted by parents has the highest correlation to cough frequency measured objectively.

Height prediction from ulna length

Height is fundamental to assessing growth and nutrition, calculating body surface area, and predicting pulmonary function in childhood. Its measurement is hindered by muscle weakness, joint, or spinal deformity. Arm span has been used as a substitute, but is inaccurate. The objective of the study was to identify a limb measurement that precisely and reproducibly predicts height in childhood. Males (n=1144) and females (n=1199), aged 5 years 4 months to 19 years 7 months, without disability were recruited from Melbourne schools. Height, arm span, ulna, forearm, tibia, and lower leg lengths were measured with a Harpenden stadiometer and anthropometer. Prediction equations for height based on ulna length (U) and age in years (A) were developed using linear regression. Ulna centile charts were developed by the LMS method. For males, height (cm)=4.605U+1.308A+28.003 (R2=0.96); for females, height (cm)=4.459U+1.315A+31.485 (R2=0.94). Intra- and inter-observer variability was 0.41% and 0.61% relative to the mean, respectively. Height prediction equations from tibia, forearm, and lower leg length were calculated. We show that ulna measurement is reproducible and precisely predicts height in school-age children. It appears to be superior to arm span measurement when neuromuscular weakness, joint, or spinal deformity exists. Ulna growth charts should facilitate growth assessment.

Early airway infection, inflammation, and lung function in cystic fibrosis

Aims: To determine the relation between lower airway infection and inflammation, respiratory symptoms, and lung function in infants and young children with cystic fibrosis (CF). Methods: A prospective study of children with CF aged younger than 3 years, diagnosed by a newborn screening programme. All were clinically stable and had testing as outpatients. Subjects underwent bronchial lavage (BL) and lung function testing by the raised volume rapid thoracoabdominal compression technique under general anaesthesia. BL fluid was cultured and analysed for neutrophil count, interleukin 8, and neutrophil elastase. Lung function was assessed by forced expiratory volume in 0.5, 0.75, and 1 second. Results: Thirty six children with CF were tested on 54 occasions. Lower airway infection shown by BL was associated with a 10% reduction in FEV0.5 compared with subjects without infection. No relation was identified between airway inflammation and lung function. Daily moist cough within the week before testing was reported on 20/54 occasions, but in only seven (35%) was infection detected. Independent of either infection status or airway inflammation, those with daily cough had lower lung function than those without respiratory symptoms at the time of BL (mean adjusted FEV0.5 195 ml and 236 ml respectively). Conclusions: In young children with CF, both respiratory symptoms and airway infection have independent, additive effects on lung function, unrelated to airway inflammation. Further studies are needed to understand the mechanisms of airway obstruction in these young patients.

Interlobar differences in bronchoalveolar lavage fluid from children with cystic fibrosis

Bronchoalveolar lavage (BAL) performed in specialist centres has improved the understanding of infant cystic fibrosis (CF) lung disease. As most researchers sample from a single lobe, it was determined whether BAL results could be generalized to other lung segments. Thirty-three CF children, aged 1.5-57 months, underwent in random order sequential BAL of their right middle and lingula lobes. Specimens from each lobe had separate quantitative bacteriology, cytology and cytokine analysis. Bacterial counts > or = 1 x 10(5) colony forming units (cfu) x mL(-1) were observed in nine (27%) subjects, including six involving only the right middle lobe. These six children had similar inflammatory indices in their right middle and lingula lobes, and interleukin (IL)-8 concentrations in the latter were significantly higher than that observed within the lingula lobes of the 24 CF children with bacterial counts < 1 x 10(5) cfu x mL(-1). Lingula neutrophil and IL-8 levels correlated best with right middle lobe bacteria numbers. This observational study in cystic fibrosis children suggests that while inflammation is detected in both lungs, bacterial distribution may be more inhomogeneous. Bronchoalveolar lavage microbiological findings from a single lobe may therefore, not be generalized to other lung segments. When performing bronchoalveolar lavage in cystic fibrosis children, it is important to sample from multiple sites.

Cough sensitivity in children with asthma, recurrent cough, and cystic fibrosis

In adults, cough sensitivity is influenced by gender and is heightened in those with non-productive cough. This study examined if cough sensitivity is (i) altered in children with asthma, recurrent cough, and cystic fibrosis and (ii) influenced by age, gender, or forced expiratory volume in one second (FEV1).  Cough sensitivity to capsaicin and spirometry were performed on 209 children grouped by the diagnosis of asthma, recurrent dry cough, cystic fibrosis, and controls. Cough sensitivity was increased in children with recurrent cough, and lower in children with cystic fibrosis when compared with children with asthma and controls. Age influenced cough sensitivity in the controls. In the asthmatics, FEV1 (% predicted) correlated to cough sensitivity measures. There was no gender difference in cough sensitivity. It is concluded that cough sensitivity is different among children with recurrent dry cough, asthma, and cystic fibrosis. In children, age, but not gender, influences cough sensitivity measures and when cough sensitivity is used in comparative studies, children should be matched for age and FEV1.

Totally implantable venous access devices in children with cystic fibrosis : incidence and type of complications

BACKGROUND Totally implantable vascular access devices (TIVADs) are accepted as a safe and effective method of facilitating long term intravenous therapy. We report our experience of the use of these devices in children with cystic fibrosis with a particular focus on the incidence and type of complications. METHODS The medical records of patients with cystic fibrosis who underwent placement of a TIVAD at the Royal Children’s Hospital, Melbourne, Australia from January 1987 to October 1996 were reviewed. Venous ultrasonography with Doppler was performed in surviving patients with a TIVAD in situ from November 1996 to April 1997 to detect occult thrombotic complications. RESULTS A total of 57 TIVADs were implanted in 44 children with a median functional duration of 700 days (range 27–3347 days). Twenty one children had devices inserted without complications. Forty eight complications (30 mechanical, 18 infectious) occurred in 36 devices in 23 children during a total functional duration of 53 057 catheter days. Mechanical complications occurred in 53% of devices (one per 1712 catheter days). Symptomatic venous thrombosis occurred five times in four patients (9%). Infectious complications occurred in 32% (one per 2948 catheter days) while sepsis occurred in five devices (9%). Doppler ultrasonography detected unsuspected thrombosis in two of 10 patients examined. CONCLUSIONS While TIVADs provided effective long term intravenous access, septic and thrombotic complications caused significant morbidity in this population. Careful patient selection, adherence to aseptic technique for access and blood sampling, and periodic ultrasonography with Doppler to detect early thrombosis may help reduce these risks.

A new use for an old Holter monitor: An ambulatory cough meter

Cough is commonly used as an outcome measure in clinical studies, although the subjective reporting of cough is unreliable when compared to objective measures. We describe an inexpensive new ambulatory cough meter that is based on a disused Holter monitor. The cough meter consists of a Holter monitor and a cough processor, designed on a computer to select the most appropriate filters. The cough meter was then validated against the overnight tape recorder on 21 occasions in 18 children (aged 6-15 yrs). The agreement between the cough meter and the tape recorder was good (mean difference of -0.3 coughs x h(-1); limits of agreement -2.2 to 1.7 coughs x h(-1)). We conclude that our newly described ambulatory cough meter provides a valid and inexpensive method of objectively monitoring cough for up to 24 h.

Successful implementation of spacer treatment guideline for acute asthma

AIMS To develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination. METHODS Defined strategies were used for the development and implementation of a guideline, assessed by a prospective, descriptive, study using notes review, and patient, nursing, and medical staff telephone contact. The setting was a tertiary referral hospital in Victoria, Australia with 25 000 yearly admissions, and asthma accounting for about 7% of total. The first 200 children and families to use the guideline after its introduction were evaluated. RESULTS A total of 191 (95.5%) children were treated according to the guideline. Six (3.0%) children were given nebulisers appropriately based on severity; five (2.5%) were given nebulisers at parental or child choice; and four (2.0 %) who did not have severe asthma, received nebulised treatment inappropriately. CONCLUSIONS Successful implementation of a new evidence based guideline can be achieved using specific strategies for promoting the application of research findings in the clinical arena.

Capsaicin cough receptor sensitivity test in children

Capsaicin has been used as a tussive agent in studies in adults to determine cough receptor sensitivity. The aim of this study was to determine the tolerance, repeatability and influence of inspiratory flow on the capsaicin cough receptor sensitivity test in children. Thirty children (mean age 11 yrs; range 6-16 yrs) were tested on two different days, to determine the lowest concentration of capsaicin required to stimulate two or more coughs (cough threshold (Cth)), 2-4 coughs (C2), and five or more coughs (C5). Capsaicin was nebulized through a dosimeter, with an arrangement that allowed the subjects to visualize and regulate their inspiratory flow. Using a constant inspiratory flow of 20 L x min(-1), tests were reproducible for C2, C5 and Cth (doubling dose changes of 1.13, 1.03 and 1.08, respectively). An increase in the inspiratory flow from 20 to 60 L x min(-1) significantly increased C2 (19.5 to 46.8 microM; p=0.016) and C5 (46.8 to 128.8 microM; p=0.008). We conclude that in children, the capsaicin cough challenge test: 1) is well-tolerated; 2) is highly repeatable; and that 3) the inspiratory flow significantly influences cough receptor sensitivity and repeatability of the test and should, thus, be regulated.

Frequency and perception of cough severity

Objective: The frequency of the common symptom of cough in children is unknown. The aim of this study was to compare cough frequency and perception of cough severity in children with and without recurrent cough.