Circadian change in bronchial responsiveness and airflow obstruction in asthmatic children.

To throw light on the question of whether the increase in bronchial responsiveness seen during the night is due to increased airflow obstruction, nine asthmatic children with increased airflow obstruction at night (group 1) were compared with nine without (group 2). The mean fall in forced expiratory volume in one second (FEV1) between 16.00 and 04.00 hours was 21.9% in group 1 and 2.3% in group 2. Selection of patients was based on the amplitude of change in peak expiratory flow (PEF) measured every four hours for three consecutive days at home. The study was performed in hospital on four consecutive days. Medication was withheld for three days before and during the measurements at home and in hospital. On the first day in hospital (day 4) FEV1 was measured every four hours for 24 hours. On day 6 inhaled histamine provocation tests were performed at the same times as the FEV1 measurements on day 4. Both groups showed a nocturnal fall in the provocative dose of histamine causing a 20% fall in FEV1 (PC20). The mean change in histamine PC20 from 16.00 to 04.00 hours was 1.1 doubling doses of histamine in group 1 and 1.5 doubling doses in group 2. The results indicate that the increase in nocturnal bronchial responsiveness that occurs at night is not due to an increase in airflow obstruction.     

Citric acid cough threshold and airway responsiveness in asthmatic patients and smokers with chronic airflow obstruction.

The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two occasions by administering doubling concentrations of citric acid. Seven of the 11 asthmatic subjects and 14 of 25 smokers with chronic airflow obstruction had a positive cough threshold on both test days. Cough threshold measurements were reproducible in both groups (standard deviation of duplicate measurements 1.2 doubling concentrations in asthma, 1.1 doubling concentrations in chronic airflow obstruction). Citric acid provocation did not cause bronchial obstruction in most patients, though four patients had a fall in FEV1 of more than 20% for a short time on one occasion only. No significant difference in cough threshold was found between the two patient groups despite differences in baseline FEV1 values. There was no significant correlation between cough threshold and the provocative concentration of histamine causing a 20% fall in FEV1 (PC20) histamine in either group. Thus sensory nerves can be activated with a tussive agent in patients with asthma and chronic airflow obstruction without causing bronchial smooth muscle contraction.     

Nocturnal enuresis in children with upper airway obstruction

This study presents the results of our experience with 115 children between the ages of 3 and 19 years who have had symptoms of upper airway obstruction and nocturnal enuresis. Twelve children had secondary enuresis, and 103 children had primary enuresis. Surgical removal of upper airway obstruction led to a significant decrease in or complete cure of nocturnal enuresis in 87 (76%) of the children studied. Eleven children were also studied with polysomnographic tracings in an attempt to determine a relationship between their sleep patterns and nocturnal enuresis.     

Perception of airflow obstruction and associated breathlessness in normal and asthmatic subjects: correlation with anxiety and bronchodilator needs.

BACKGROUND--Perception of bronchoconstriction varies between individuals and its determinants remain to be identified. The perception of airflow obstruction and breathlessness during induced bronchoconstriction was studied, and the effects of anxiety, repetition of the stimulus, and bronchodilator needs on these measurements were examined in normal and asthmatic subjects. METHODS--Fifteen normal (control) and 25 asthmatic subjects had two consecutive methacholine inhalation tests to induce a 20-50% fall in FEV1. Evaluation of the perceived magnitude of airflow obstruction, breathlessness, level of anxiety generated, and bronchodilator needs was obtained before each FEV1 measurement on a modified Borg scale from 0 to 10. RESULTS--Mean (SE) maximal fall in FEV1 in asthmatic and control subjects was of similar magnitude: test 1, 37.6 (1.4)% and 38.7 (3.1)%, and test 2, 36.0 (1.6)% and 27.7 (2.4)% respectively. There was a large interindividual variation in perception of airflow obstruction and breathlessness but, although they were well correlated in asthmatic subjects, they were perceived differently by the control subjects. Perception of airflow obstruction was greater in asthmatic subjects. The level of anxiety and the bronchodilator use were low and did not influence perception. CONCLUSIONS--During induced bronchoconstriction, the overall perception of airflow obstruction and breathlessness were similar among asthmatic subjects but controls showed a higher perception of airflow obstruction for any given level of breathlessness. Asthmatic subjects perceived airflow obstruction and breathlessness to a greater degree than did controls but anxiety and bronchodilator need were not correlated with respiratory sensation. The variability of bronchodilator use for similar degrees of bronchoconstriction suggests that it may be misleading to assess the severity of asthma control using only this indirect measure.     

Topical lidocaine reduces the risk of perioperative airway complications in children with upper respiratory tract infections

Purpose

To determine the effect of topically applied lidocaine on perioperative airway complications when using a laryngeal mask airway device (LMAD) in children either with or without a history of recent or ongoing upper respiratory tract infection (URI).

Methods

In a randomized controlled double-blind trial, 34 children with a history of recent or ongoing URI and 32 non-URI children— all of whom were younger than age ten and scheduled to undergo minor surgical procedures—were randomly assigned to either a lidocaine or a placebo group. In the lidocaine group, an LMAD was lubricated with lidocaine gel before insertion, and a clear lubricating gel was used in the placebo group. The following data were recorded after standardized anesthesia induction and airway management: postoperative complications, such as coughing, desaturation, laryngospasm, and increased oral secretions, as well as length of stay in the postanesthetic recovery unit.

Results

Children with URI had a lower overall perioperative complication rate if they received a lidocaine gel (35%) rather than placebo (94%) (P < 0.01). Also, the incidence of postoperative coughing was less (12% vs 53%; P = 0.03). In non-URI patients, lidocaine did not significantly reduce the rate of airway complications compared with placebo (17% vs 24%, respectively).

Conclusion

Lubrication of the LMAD with lidocaine gel reduces the incidence of airway complications in children with an upper respiratory tract infection.     

Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women

BACKGROUND: Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women. METHODS: Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks. RESULTS: Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=-0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2 (r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=-0.512; p=0.051) and respiratory symptom severity score (r= -0.567; p=0.043), probably due to the masking effects of bronchodilator treatment. CONCLUSIONS: Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators.     

Surgical treatment of paraosmia secondary to an upper respiratory infection

Many people experience some degree of olfactory dysfunction during the acute stages of an upper respiratory infection (URI). The olfactory function usually returns to the preinfection level in few days. In some cases, the dysosmia remains even after the reopening of the air passageways. The olfactory loss after URI associates an hyposmia and odor distortions. We report a rare case of odor distortions after URI treated by surgery.     

Increased maintenance corticosteroids during upper respiratory infection decrease the risk of relapse in nephrotic syndrome

Relapses are common in children with idiopathic nephrotic syndrome, and this prospective study looks into the possibility of decreasing the frequency of relapses in a selected group of such patients. The study includes 36 children with a steroid-dependent, relapsing nephrotic syndrome on a maintenance prednisone therapy of about 0.5 mg/kg every other day. They were prospectively divided into two groups with comparable age and sex distribution and the number of those who had previously received cyclophosphamide therapy. Group 1 patients were advised to take daily prednisone for 5 days, starting at the time of the onset of an upper respiratory tract infection (URI). No such advice was given to those in group 2, and they remained on alternate-day prednisone during URI. At the end of a 2-year follow-up period, the total number of relapses in group 1 was 40 with a mean of 2.2 +/- 0.87 per patient as compared with 99 with a mean of 5.5 +/- 1.33 per patient in group 2 (p = 0.04). We conclude that an increased maintenance prednisone during URI helps decrease significantly the number of relapses in those on alternate-day therapy.     

The relation between upper respiratory tract infection and mild hypoxemia during general anesthesia in children]

Anesthesiologists often face the problem of a child with symptoms of an acute upper respiratory infection (URI) presenting for surgery. Anesthesia in the presence of uncomplicated URI may not be contraindicated. However, we experienced three cases of such children in which lung atelectasis developed after the induction of general anesthesia. Because continuous monitoring of arterial oxygen saturation by pulse oximetry (SpO2) was useful for detecting mild hypoxemia in these patients, we retrospectively examined the possible association between URI symptoms and SpO2 in 63 children. Patients with symptoms of URI showed a significantly high incidence of decreased SpO2 to below 95% for 5 minutes. Our results suggest that, with URI symptoms even uncomplicated, symptomatic patients have increased risks for the development of mild hypoxemia during anesthesia.     

Risk factors for perioperative adverse respiratory events in children with upper respiratory tract infections

BACKGROUND: Anesthesia for the child who presents for surgery with an upper respiratory infection (URI) presents a challenge for the anesthesiologist. The Current prospective study was designed to determine the incidence of and risk factors for adverse respiratory events in children with URTs undergoing elective surgical procedures. METHODS: The study population included 1,078 children aged 1 month to 18 yr who presented for an elective surgical procedure. Parents were given a short questionnaire detailing their child's demographics, medical history, and presence of any symptoms of a URT. Data regarding the incidence and severity of perioperative respiratory events were collected prospectively. Adverse respiratory events (any episode of laryngospasm, bronchospasm, breath holding > 15 s, oxygen saturation < 90%, or severe cough) were recorded. In addition, parents were contacted 1 and 7 days after surgery to determine the child's postoperative course. RESULTS: There were no differences between children with active URIs, recent URIs (within 4 weeks), and asymptomatic children with respect to the incidences of laryngospasm and bronchospasm. However, children with active and recent URIs had significantly more episodes of breath holding, major desaturation (oxygen saturation < 90%) events, and a greater incidence of overall adverse respiratory events than children with no URIs. Independent risk factors for adverse respiratory events in children with active URIs included use of an endotracheal tube (< 5 yr of age), history of prematurity, history of reactive airway disease, paternal smoking, surgery involving the airway, the presence of copious secretions, and nasal congestion. Although children with URIs had a greater incidence of adverse respiratory events, none were associated with any long-term adverse sequelae. CONCLUSIONS: The current study identified several risk factors for perioperative adverse respiratory events in children with lulls. Although children with acute and recent URIs are at greater risk for respiratory complications, these results suggest that most of these children can undergo elective procedures without significant increase in adverse anesthetic outcomes.