The Differences in Acute Management of Asthma in Adults and Children

Acute asthma or wheeze is a common presentation to emergency services for both adults and children. Although there are phenotypic differences between asthma syndromes, the management of acute symptoms follow similar lines. This article looks at the similarities and differences in approaches for children and adults. Some of these may be age dependent, such as the physiological parameters used to define the severity of the attack or the use of age appropriate inhaler devices. Other differences may reflect the availability of evidence. In other areas there is conflicting evidence between adult and pediatric studies such as a temporary increase in dose of inhaled corticosteroids during an acute attack. Overall there are more similarities than differences.

Pneumothorax from subpleural blebs-a new association of sotos syndrome?

We describe two unrelated patients with molecularly confirmed Sotos syndrome with multiple subpleural blebs and pneumothorax. We propose this as a new association. Patient 1 is a 3-year-old boy with a 1.9 Mb interstitial deletion of the long arm of chromosome 5, with breakpoints at q35.2 and q35.3, encompassing NSD1 and Patient 2 is a 9-year-old girl with a de novo truncating mutation within NSD1. Both patients presented with sudden onset dyspnea due to a unilateral pneumothorax: Patient 1 at the age of 18 months and Patient 2 at 9 years. In both, the pneumothorax recurred following removal of the chest drain and, on further investigations, multiple subpleural blebs were identified necessitating a pleurodesis and tissue resection. This is the first report of multiple subpleural blebs leading to pneumothorax in association with Sotos syndrome. Given the similar and unusual presentation in the two affected patients, we suggest that this may be a real association, albeit a rare one. While screening would not be advocated for such a rare association, we recommend that clinicians consider pneumothorax in patients with Sotos syndrome and sudden onset of dyspnea and are aware that it may be refractory to first line treatment.

To clip or not to clip? Noseclips for spirometry

The use of noseclips for open-circuit spirometry is sporadic, despite guidelines encouraging their use. The authors aimed to evaluate whether noseclips significantly affected measurements of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) in children attending a tertiary, paediatric respiratory centre. Children attending the asthma and cystic fibrosis (CF) clinics were asked to perform two sets of spirometry, one with and one without noseclips in random order, 20-min apart. Paired data was obtained on 62 patients (32 asthma, 30 CF) with a median age of 11.4 yrs (range 7.2-17.2 yrs). There were no systematic differences in FEV1 or FVC measured with and without noseclips, although seven children (11%) had clinically significant differences in FEV1 of >190 mL. There is no clear advantage to wearing noseclips when performing open-circuit spirometry. Individuals should be assessed to ascertain their optimal technique, which should then be used consistently in clinical practice. Noseclips should probably be retained for research protocols.

Partial liquid ventilation and nitric oxide in experimental acute lung injury

OBJECTIVE

To investigate the effects of inhaled nitric oxide (iNO) and partial liquid ventilation (PLV) on oxygenation and pulmonary haemodynamics in acute lung injury (ALI), and to assess their effects on lung function, systemic haemodynamics and lung injury.

METHODS

Using saline lung lavage, ALI was induced in 18 piglets. A control group was ventilated with conventional mechanical ventilation (CMV) for 2 h. An iNO-first group received iNO for the first hour and then iNO with PLV. A PLV-first group received PLV for the first hour and then PLV with iNO. Variables were measured at baseline, 5 min postlavage, and at 1 h and 2 h postlavage.

RESULTS

During the first hour, both treatment groups showed improvement in oxygenation index (OI). At 2 h, the dif-ferences in OI were statistically significant (P = 0.037), with a mean +/- SD of 23.8 +/- 20.7 in the control group, 4.4 +/- 0.9 in the PLV-first group and 6.5 +/- 3.1 in the iNO-first group. The OI was similar in both treatment groups (P = 0.178). At 2 h, the pulmonary artery pressure (PAP) was significantly different (P = 0.04) between groups, with a mean +/- SD PAP of 36.3 +/- 7.2 mmHg in the control group, 27.4 +/- 4.0 mmHg in the PLV-first group and 30.0 +/- 4.1 mmHg in the iNO-first group. The PAP was similar in both treatment groups (P = 0.319).

CONCLUSION

In ALI, oxygenation and pulmonary hypertension are improved with PLV and iNO given together, regardless of the order in which they are commenced.

Assessment of a low-cost home monitoring spirometer for children

Electronic devices are now available to measure and store lung function parameters in the home. Before adopting a device for clinical or research use, it is important to validate it in the target patient group. The aim of this study was to assess a low-cost, portable, logging spirometer, the VM Plus (VM), against a standard laboratory Jaeger spirometer (JS) for use in children with respiratory disease. Seventy children with stable asthma or cystic fibrosis performed spirometry on the two devices, and results for peak expiratory flow (PEF) and forced expiratory volume in 1 sec (FEV(1)) were compared. Comparison was made both using the two devices separately (separate method) and with the devices connected in series (series method). Reproducibility of the VM measurements was also assessed. Correlation between measurements was close (R values: separate, PEF, 0.91; FEV(1), 0.94; series, PEF, 0.97, FEV(1), 0.99), but PEF readings on the VM Plus were substantially higher than with the JS (mean difference: separate, 54.8 L/min; series, 28.2 L/min). This reflects well-reported differences in PEF measurements between the Mini-Wright PEF meter, on which the VM Plus spirometer is based, and conventional spirometers. Limits of agreement (series method) were: PEF, -13.2 to +69.6 L/min; FEV(1), -0.03 to +0.19 L. Reproducibility of VM Plus measurements was acceptable: coefficient of variation for PEF was 4%; for FEV(1), 4.3%; coefficient of reproducibility for PEF, 39 L/min; for FEV(1), 0.26 L. The VM Plus provides reasonably accurate, reproducible measurements of PEF and FEV(1), but intrinsic bias, particularly in PEF measurement, needs to be taken into account. Its potential to document longitudinal changes in lung function in children with respiratory disease at home merits further study.

Short acting beta agonists for recurrent wheeze in children under 2 years of age

BACKGROUND

Wheeze is a common symptom in infancy and is a common cause for both primary care consultations and hospital admission. Beta2-adrenoceptor agonists (b2-agonists) are the most frequently used as bronchodilator but their efficacy is questionable.

OBJECTIVES

To determine the effectiveness of b2-agonist for the treatment of infants with recurrent and persistent wheeze.

SEARCH STRATEGY

Relevant trials were identified using the Cochrane Airways Group database (CENTRAL), Medline and Pubmed. The database search used the following terms: Wheeze or asthma and Infant or Child and Short acting beta-agonist or Salbutamol (variants), Albuterol, Terbutaline (variants), Orciprenaline, Fenoterol

SELECTION CRITERIA

Randomised controlled trials comparing the effect of b2-agonist against placebo in children under 2 years of age who had had two or more previous episodes of wheeze, not related to another form of chronic lung disease.

DATA COLLECTION AND ANALYSIS

Eight studies met the criteria for inclusion in this meta-analysis. The studies investigated patients in three settings: at home (3 studies), in hospital (2 studies) and in the pulmonary function laboratory (3 studies). The main outcome measure was change in respiratory rate except for community based studies where symptom scores were used.

MAIN RESULTS

The studies were markedly heterogeneous and between study comparisons were limited. Improvement in respiratory rate, symptom score and oxygen saturation were noted in one study in the emergency department following two salbutamol nebulisers but this had no impact on hospital admission. There was a reduction in bronchial reactivity following salbutamol. There was no significant benefit from taking regular inhaled salbutamol on symptom scores recorded at home.

REVIEWER'S CONCLUSIONS

There is no clear benefit of using b2-agonists in the management of recurrent wheeze in the first two years of life although there is conflicting evidence. At present, further studies should only be performed if the patient group can be clearly defined and there is a suitable outcome parameter capable of measuring a response.

Partial liquid ventilation compared with conventional mechanical ventilation in an experimental model of acute lung injury

OBJECTIVE

To compare the effects of partial liquid ventilation with conventional mechanical ventilation on oxygenation and pulmonary mechanics in saline lavaged rabbits.

METHODS

Following acute lung injury (saline-lavage), rabbits were assigned to continue conventional mechanical ventilation (n = 6) or commence partial liquid ventilation (n = 6). In both groups the inspired oxygen concentration was 100% throughout the study. The target PaCO2 of 40-60 mmHg was accomplished by keeping the tidal volume between 7 and 10 mL/kg. During the study the peak inspiratory pressure was adjusted to maintain the target PaCO2. Arterial blood gases were taken pre-lavage, immediately post-lavage (time = 0) and then hourly for 5 hours. Pulmonary mechanics were estimated by measuring compliance and resistance. Pulmonary function was measured pre-lavage, immediately post-lavage and at 1 and 5 hours. At 5 hours the rabbits were killed and the lungs were removed for histological examination.

RESULTS

Baseline PaO2, compliance and resistance were not significantly different between groups. The partial liquid ventilation group had a higher PaO2 and a significantly better oxygenation index one hour after commencing partial liquid ventilation and a significantly higher PaO2 averaged over the three hours post-treatment. There were no significant differences in compliance, resistance or lung damage scores.

CONCLUSIONS

In this experimental model of acute lung injury, partial liquid ventilation resulted in immediate and sustained increase in PaO2 over 3 hours without significant change in lung mechanics or histological lung damage.

Oxygenation is not improved by partial liquid high frequency ventilation using a high lung volume strategy. An experimental study

OBJECTIVE

To investigate the effect on oxygenation and lung damage of partial perfluorocarbon liquid high frequency oscillatory ventilation (PL-HFOV) versus high frequency oscillatory ventilation (HFOV) alone, in rabbits with acute lung injury, using high lung volume strategy HFOV.

METHODS

Twelve adult New Zealand white rabbits were initially ventilated with HFOV after anaesthesia, sedation and paralysis. After induction of lung injury with saline lavage, all animals received a single sigh breath of 30 cmH(2)O for 30 seconds. They were then allocated to receive either HFOV alone (n = 6) or PL-HFOV (n = 6). Arterial blood gases were taken pre- and post-lavage and then hourly for 5 hours. The oxygenation index (OI, in cmH(2)O/mmHg) was calculated using the formula: OI = (MAP x F(I)O(2) x 100) / PaO(2). The lungs were then removed for histological examination to score lung injury.

RESULTS

Two rabbits died in the PL-HFOV group and none in the HFOV group, p = 0.45 (Fisher's exact test). At one hour the oxygenation index (OI) was 4.5 in the HFOV group and 6.6 in the PL-HFOV group, p = 0.49 and the PaO(2) was 374 mmHg in the HFOV group and 311 mmHg in the PL-HFOV group, p = 0.39. Average OI over the first three hours was 3.6 in the HFOV group and 5.0 in the PL-HFOV group, p = 0.27 and the PaO(2) was 404 mmHg in the HFOV group and 337 mmHg in the PL-HFOV group, p = 0.12. The lung histology damage score was 2.33 in the HFOV group and 2.50 in the PL-HFOV group, p = 0.83.

CONCLUSIONS

In this model of acute lung injury, using a high volume HFOV strategy to optimise lung recruitment, PL-HFOV did not result in any further improvement in oxygenation when compared with HFOV alone. The question of safety with PL-HFOV remains.

Changes in lung function between age 8 and 14 years in children with birth weight of less than 1,501 g

We set out to determine whether lung function of children with a birth weight of <1,501 g changed relative to expectations between the ages of 8 and 14 years. We hypothesized that changes in lung function may differ between those of birth weight above and below 1,000 g. The subjects of this study were born in the Royal Women's Hospital, Melbourne. There were 86 consecutive survivors with birth weights <1,000 g born between January 1, 1977 and March 31, 1982, and 124 consecutive survivors with birth weights 1,000-1,500 g born between October 1, 1980 and March 31, 1982. Lung function was measured at both age 8 and 14 years, corrected for prematurity in 78% (67/86) of those with birth weight <1,000 g, and in 69% (86/124) of those with birth weight 1,000-1,500 g. Overall, lung function was similar to predicted values at both 8 and 14 years of age [e.g., (forced expired volume in 1 s, FEV1% predicted) at age 8 years mean 88.5% (SD 14.7) and at age 14 years, mean 94.9% (SD 13.8)]. There were significant changes, mostly improvements, in lung function between age 8-14 years relative to predicted values: FEV1 (% predicted) increased between 8-14 years of age by a mean of 6.4 (95% confidence interval, 4.4-8.3). The improvements in some lung function variables were significantly greater in those of birth weight <1,000 g compared with those of birth weight 1,000-1,500 g: improvement in FEV1 (% predicted) between age 8-14 years in infants with birth weight <1,000 g had a mean of 10.3 (SD 13.1), and in those with birthweight 1,000-1,500 g a mean of 3.3 (SD 10.1). We conclude that lung function improved significantly relative to predicted values in children of birth weight <1,501 g between age 8-14 years. The improvements were greatest in those of birth weight <1,000 g.