Respiratory symptoms or signs on the day of the study alter pulmonary function in teenagers

Common cold decreases lung function in infants with recurrent wheezing

Background

Common acute viral respiratory infections (colds) are the most frequent cause of exacerbations in infants with recurrent wheezing (RW). However, there is no quantitative information about the effect of colds on the lung function of infants with RW. This study was undertaken to determine the effect of common cold on forced expiratory parameters measured from raised lung volume in infants with RW.

Methods

Spirometric lung function (expiratory flows from raised lung volume) was randomly assessed in 28 infants with RW while they had a common cold and when asymptomatic.

Results

It was found that during colds there was a significant decrease in all forced expiratory parameters and this was much more evident for flows (FEF_50%, FEF_75% and FEF_25–75%) which were definitively abnormal (less than −1.65 z-score) in the majority of infants. There was not association between family asthma, tobacco exposure, and other factors, with the extent of lung function decrease during colds. Tobacco during pregnancy but not a history of family asthma was significantly associated to lower expiratory flows; however, the association was significant only when infants were asymptomatic.

Conclusion

This study shows that common colds cause a marked reduction of lung function in infants with RW.

Bronchodilator premedication does not decrease respiratory adverse events in pediatric general anesthesia

PURPOSE

Upper respiratory infections (URI) presage perioperative respiratory complications, but thresholds to cancel surgery vary widely. We hypothesized that autonomically-mediated complications seen during emergence from anesthesia would be predicted by capnometry and reduced with preoperative bronchodilator administration.

METHODS

Afebrile outpatient tertiary-care children (age two months to 18 yr, n = 109) without lung disease or findings, having non-cavitary, non-airway surgery for under three hours, were randomized to bronchodilator premedication vs placebo and had preoperative capnometry. After halothane via mask, laryngeal mask airway, or endotracheal tube, and regional anesthesia as appropriate, patients recovered breathing room air while cough, wheeze, stridor, laryngospasm, and cumulative desaturations were recorded for 15 min.

RESULTS

In this specific population, there was no association between adverse events and either URI within six weeks (n = 76) or URI within seven days (n = 21). Neither albuterol nor ipratropium premedication decreased adverse events. Endotracheal intubation was associated with increased emergence desaturations and placebo nebulized saline increased emergence coughing. Neither anesthesiologists nor preoperative capnometry predicted adverse events.

CONCLUSIONS

Adverse events were neither predicted nor prevented. In afebrile outpatient ASA I and II children with no lung disease or findings, having non-cavitary, non-airway surgery for under three hours, there was no association between either recent URI or active URI and desaturation, wheeze, cough, stridor, or laryngospasm causing desaturation (all P > 0.05). In this highly selected population of afebrile patients, the results suggest that anesthesiologists may proceed with surgery using specific criteria in the presence of a URI.

Impact of respiratory illness on expiratory flow rates in normal, asthmatic, and allergic children

We examined the effects of current respiratory illness (RI) on pulmonary function (PF) in 1,103 subjects who underwent spirometry at schools twice within a 4-month period. Before spirometry, subjects were asked if they had a "cold or other chest illness" during the previous month, and if so, whether they had fully recovered. Those who had not recovered were considered to have an RI. We found that children without RI at their first PF test who reported RI on retest had significantly lower forced expiratory volume in 1 sec (FEV(1)) (-0.8%), peak expiratory flow rate (PEFR) (-2.2%), forced expiratory flow between 25-75% of vital capacity (FEF(25-75)) (-3.5%), and forced expiratory flow at 75% of vital capacity (FEF(75)) (-5.1%) than those without RI on both test and retest. Restriction of subjects to those without a history of doctor-diagnosed asthma did not appreciably change these findings. Children with hay fever had significantly larger RI-associated decreases for FEV(1), FEF(25-75), and FEF(75), but not PEFR, than those without hay fever. Among asthmatic subjects, those with active asthma had larger RI-associated decreases in FEF(25-75) and FEF(75), but not PEFR, than those without asthma. There was limited evidence that small airway losses were greater in children less than 12.5 years old. We conclude that RI in children who are well enough to attend school may reduce expiratory flow rates. These effects are greater for children with active asthma or hay fever than in those without, and may be inversely related to age.

Snoring in French preschool children

The prevalence of habitual snoring and its associations with respiratory symptoms, personal and familial risk factors, ear, nose, and throat (ENT) abnormalities, and its influence on ventilatory function were studied in a sample of 190 children aged 5 to 6 years from nine kindergartens in Nancy (northeastern France). Nineteen (10%; 95% CI 5.7-14.3%) of the children were habitual snorers; the prevalence was the same in boys and girls. In univariate analysis habitual snoring was significantly associated with a personal history of exercise-induced bronchospasm [relative risk (RR) 4.50]; a history of adenotonsillectomy (RR, 2.56); a personal history of allergy (RR, 2.83); a sibling history of atopy (RR, 2.39); and doctor-assessed tonsillar hypertrophy (RR, 2.51). These factors were entered into a logistic regression model that retained as independent determinants exercise-induced asthma, personal history of allergy, sibling history of allergy, and tonsillar hypertrophy. The height-adjusted peak expiratory flow rate was slightly, non-significantly lower in habitual snorers as compared to non-snorers (2.01 +/- 0.32 vs 2.10 +/- 0.38 L/s/m2). Due to the limited numbers in the sample, the increased risk for paternal (RR, 1.8) and maternal (RR, 1.6) smoking at home remained nonsignificant.

Determinants of alveolar nitrogen slope and closing volumes in healthy adolescents

The alveolar nitrogen slope (PIII), closing volume (CV), and closing capacity (CC) were measured by the single-breath nitrogen washout method (SBN2) in a group of 187 healthy children and adolescents (92 boys, 95 girls), 10 to 16 yr old, from the general population of Lorraine, France. The test was performed using a computerized system, which also made the calculations. About one out of five healthy subjects in this population were unable to satisfactorily perform the test; the failure rate was the same for the two sexes (20% in boys, 21.5% in girls) and significantly higher in younger children (26.6 and 14.5% for children under and over the age of 13, respectively; p = 0.03). The distribution of results was skewed for PIII and practically normal for log PIII, CV, VC, and CV/VC or CC/TLC ratios. PIII was highly significantly, inversely related to anthropometric variables; the highest coefficient was that for the age-weight interaction term in boys (= r -0.57 for PIII, -0.62 for log PIII) and for weight in girls (r = -0.57 for both PIII and log PIII). Because the anthropometric variables were strongly interrelated (r between 0.45 and 0.79), multiple regressions did not materially improve the prediction of PIII. In simple regression, weight alone explained 36% of the variability of log PIII in boys and 32% in girls. The mean PIII was significantly higher in girls as compared to boys (1.14 +/- 0.38 versus 0.98 +/- 0.17% N2/L, p = 0.02); CV and CC in milliliters were related to body build as other lung volumes; the CV/VC in girls and CC/TLC ratio in both sexes were not related to anthropometric variables. In boys, CV/VC decreased significantly with height (p = 0.035 for CV/VC versus height3).

Infants with upper respiratory illnesses have significant reductions in maximal expiratory flow

We studied maximal expiratory flows at functional residual capacity (VmaxFRC) obtained by use of the chest compression technique in 9 infants who had signs of upper respiratory illness (URI) at the time of testing, and in 9 infants who were symptom-free but whose parents reported they had a URI in the previous month. When compared to 109 infants with no URI, infants with current URI had 40% lower VmaxFRC (mean +/- SD: 125.7 +/- 54.5 mL/s vs. 73.6 +/- 53.6 mL/s; P less than 0.01). Infants with a past URI had mean values for VmaxFRC (120.2 +/- 50.2 mL/s) that were not significantly different from those of infants with no URI. Changes in the shape of the flow-volume loop analogous to those reported in infants with lower airway obstruction were also noticed in infants with current URI. These findings suggest that, as in older children and adults, clinically unapparent alterations in lower airway function occur during URI in infants.

Pulmonary function following mild respiratory tract infections ("common cold") in teenagers

Ventilatory function--forced vital capacity (VC)--forced expiratory volume (in 1-sec forced expiratory flows) static lung volumes, closing volume, and phase III slope (single-breath N2 test) were compared in 94 children with and 436 children without a history of recent mild acute respiratory infection. Their age ranged from 10 to 16 years; subjects with symptoms on the day of the study were excluded. We found no difference in lung function between the two groups, with the exception of a slight (inconsistently significant) increase in closing volume (CV) and the CV/VC ratio. Although the influence of a persistent increase in interstitial lung pressure leading to early small airways closure cannot be ruled out, this isolated functional abnormality probably represents a spurious positive result, arising by chance when a large number of statistical tests are done.