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Biomedical subjects

G C Geelhoed

Publications and source records attributed to G C Geelhoed.

16 recordsLinked to original sources

Croup.

The management of mild to severe croup has undergone dramatic changes in the last 5 years, primarily due to the increased understanding of the benefits of treating it with steroids. Steroids have been used in the treatment of croup for many years, but, until recently, their use has remained controversial. Earlier studies were often not blinded or used inappropriate outcome measures, such as respiratory rate, which have not proven appropriate. Two attempts to review the literature in 1980 and 1989 cautiously supported the use of steroids. Despite these recommendations many practitioners continued to view croup in most cases as a benign self-limited condition, and since steroids have potential side-effects, their use was not considered justified. More recently, however, a number of developments such as the successful use of the inhaled steroid budesonide and oral dexamethasone have reinforced the argument for using steroids. Recent work has also shown that both inhaled and systemic steroids work by 1 hour and dramatically reduce morbidity and hospitalization time. The demonstration that an oral dose of 0.15 mg/kg dexamethasone is as effective as larger doses has made the use of systemic steroids more acceptable to many practitioners. All children with croup severe enough to be admitted to hospital should receive steroids. Two recent studies have shown that steroids also benefitted children who presented to emergency departments for treatment, but whose croup was not considered severe enough for admission. The type of steroid, the dose, and the mode of administration will need to be decided by the attending clinician.

Administration, Inhalation

Efficacy of a small single dose of oral dexamethasone for outpatient croup: a double blind placebo controlled clinical trial.

OBJECTIVE: To assess the efficacy of a single dose of oral dexamethasone 0.15 mg/kg in children with mild croup not admitted to hospital. DESIGN: Double blind, randomised, placebo controlled clinical trial. SETTING: The emergency department of a tertiary paediatric hospital. SUBJECTS: 100 children aged 4-122 months presenting with mild croup. INTERVENTION: A single oral dose of dexamethasone 0.15 mg/kg or placebo. MAIN OUTCOME MEASURE: Return to medical care with ongoing croup. RESULTS: Baseline characteristics of the two treatment groups were similar. Eight children (all from the placebo group) returned to medical care with ongoing croup, one being admitted. There was no reported difference in duration of croup symptoms, duration of viral symptoms, or rate of return to medical care for other reasons. CONCLUSION: Oral dexamethasone in a dose of 0.15 mg/kg is effective in reducing return to medical care with ongoing croup in children with mild croup.

Administration, Oral

Sixteen years of croup in a Western Australian teaching hospital: effects of routine steroid treatment.

STUDY OBJECTIVE: To describe the experience of croup at Princess Margaret Hospital for Children (PMH), the only tertiary pediatric hospital in Western Australia, from 1980 through 1995 with reference to the introduction of routine steroid treatment in the ICU in 1989, in the general hospital wards from 1989 through 1993, and in the emergency department observation ward in 1993. METHODS: Information on the numbers of children with croup presenting to PMH from 1980 through 1985 who were admitted to the general wards, the ICU, and the observation ward; intubation rate; and length of stay was obtained from a combination of state health records, hospital statistics, logbooks, and computer records. RESULTS: The numbers of children who presented to and were admitted to PMH with croup were similar for all years of the study period. Since 1989, the annual number of children intubated (1980-1989 average, 8; 1990-1995 average, 4) and total ICU days for croup (1980-1989 average, 129; 1990-1995 average, 24) has decreased dramatically. The annual percentage of children transferred to the ICU (1980-1989 average, 11.6%; 1994-1995 average, 2.6%) and the average length of stay for PMH (1980-1989 average, 2.03 days; 1994-1995 average, 1.1 days) decreased every year from 1989 through 1994, coincident with increasing use of steroids for croup in the general wards. The change of policy from no steroids to compulsory use of steroids in the observation ward coincided with an increase in the percentage of children discharged home directly from the observation ward (to 97% from 80%). CONCLUSION: The introduction of steroids at PMH coincided with a dramatic decrease in measures of severity for children admitted to hospital with mild to severe croup. All children hospitalized with croup should receive steroid therapy.

Child, Preschool

Oral and inhaled steroids in croup: a randomized, placebo-controlled trial.

It was the objective of this study to compare the efficacy of oral dexamethasone and inhaled budesonide in children hospitalized with croup, using a three-way, double blind, randomized, placebo-controlled clinical trial design. The trial was carried out in the Emergency Department Observation Ward of a tertiary pediatric hospital. The subjects for the study were 80 children (age range 5 to 158 months) who were hospitalized with croup. Children received either 2 mg of nebulised budesonide, dexamethasone syrup (0.6 mg/kg) or a placebo. Median duration of hospitalization was shorter for children treated with dexamethasone (12 hr) and budesonide (13 hr) compared to placebo (20 hr) (P < 0.03). There was no significant difference in hospitalization time between children treated with dexamethasone and budesonide. Median time to a croup score of < or = 1 was shorter for children treated with dexamethasone (2 hr) or budesonide (3 hr) compared to those who received placebo (8 hr) (P < 0.01). Croup scores for both steroid groups were significantly lower than the placebo group by 1 hr and remained so subsequently. The croup scores did not differ significantly in the 2 steroid treated groups. Six of the 30 children (20%) in the placebo group required adrenaline after the first hour compared to none of the 50 children in the steroid treated groups (P < 0.02). We conclude that oral dexamethasone and inhaled budesonide are both effective in reducing symptoms and duration of hospitalization in children with croup.

Administration, Inhalation

Oral dexamethasone in the treatment of croup: 0.15 mg/kg versus 0.3 mg/kg versus 0.6 mg/kg.

The objective of this study was to compare the efficacy of a single dose of oral dexamethasone of varying sizes in 120 children hospitalized with croup in two sequential double blind, randomized, controlled clinical trials (Trials A and B). The study was conducted in the Emergency Department Observation Ward of a tertiary pediatric hospital. One hundred and twenty children (age range 6 to 160 months) hospitalized with croup participated. Baseline characteristics for the two groups in each trial were similar. In Trial A 60 children received either 0.6 or 0.3 mg/kg dexamethasone syrup; in Trial B 60 children received either 0.3 or 0.15 mg/ kg dexamethasone syrup. Duration of hospitalization, reduction in croup scores, and adrenaline usage were evaluated. Median duration of hospitalization was similar for children in Trial A (7 and 8 hr), and in Trial B (9 and 9 hr). Croup scores following treatment did not differ and were significantly lower than initial scores for all groups and in each trial. Other outcome measures were similar for the two groups in each trial, including need for nebulized adrenaline, numbers of patients admitted to intensive care, rate of return to medical care with reoccurrence of croup, and readmission to hospital with croup following discharge from hospital. We conclude that oral dexamethasone in a dose of 0.15 mg/kg is as effective as 0.3 or 0.6 mg/kg in relieving symptoms and results in a similar duration of hospitalization in children with croup.

Child, Preschool

Evaluation of SaO2 as a predictor of outcome in 280 children presenting with acute asthma.

STUDY OBJECTIVES: To evaluate the initial measurement of arterial oxygen saturation (SaO2) as a predictor of outcome in acute childhood asthma compared with other factors of past and present asthma history. DESIGN: Prospective observational double-blind study. SETTING: The emergency department of an urban pediatric hospital with a 1988 annual census of 50,000 children. TYPE OF PARTICIPANTS: Two hundred eighty children with recurrent wheezing that was diagnosed by a physician as asthma, who presented to the ED with wheezing. INTERVENTION: SaO2 was measured on arrival in the ED, and a detailed history of the present attack and past asthma was recorded. Children were treated according to then-current practice guidelines. Parents were contacted by telephone to determine the outcome of the attack; a "poor outcome" was defined as admission to hospital or re-presenting with ongoing symptoms to receive medical care if sent home from the ED. A "worst outcome" was defined as receiving IV aminophylline and steroids after failing to respond to repeated bronchodilation and oral steroids. MEASUREMENTS AND MAIN RESULTS: The proportion of children at each percent SaO2 who had a poor outcome increased with decreasing SaO2 (r = .97). Likelihood ratios for a poor outcome were 35 (confidence interval [CI], 11 to 150) for an SaO2 of 91% or less compared with 96% or more and 4.2 (CI, 2.2 to 8.8) for an SaO2 of 92% to 95% compared with 96% or more. An SaO2 of 91% or less predicted with a sensitivity of 100% and a specificity of 84% those children with a worst outcome who required IV therapy. Other factors of current or past asthma history failed to predict outcome. CONCLUSION: We have shown that in acute childhood asthma, the initial level of SaO2 reflects severity as it predicts the likelihood of poor outcome. This predictive quality of SaO2 is independent of current or past clinical factors.

Acute Disease

A comparison of a bodyweight dose versus a fixed dose of nebulised salbutamol in acute asthma in children.

OBJECTIVE: To compare the efficacy of salbutamol as a fixed dose Ventolin Nebule (2.5 mg) and as variable dose respirator solution (0.1 mg/kg bodyweight). DESIGN: Multicentre, randomised, double-blind, parallel group comparison. SETTING: The Emergency Departments of the Royal Children's Hospital, Melbourne, Victoria; Princess Margaret Hospital for Children, Perth, Western Australia; and The Children's Hospital, Sydney, New South Wales. PATIENTS: Ninety-nine children between four and 12 years of age who presented to the Emergency Departments with mild to moderate acute asthma from May to December 1990. INTERVENTIONS: Children enrolled in the study were randomly allocated to one of two groups. Group 1 received one Nebule (2.5 mg salbutamol in 2.5 mL aqueous solution) delivered by wet nebulisation. Group 2 received salbutamol (approximately 0.1 mg/kg bodyweight) diluted with saline to 2.5 mL, delivered by identical wet nebulisation. MAIN OUTCOME MEASURES: (i) Clinical score; (ii) pulse oximetry; and (iii) peak expiratory flow rate (PEFR) where possible--measured before, and at 15 and 30 minutes after treatment with salbutamol. RESULTS: The clinical score significantly improved in both treatment groups after 15 minutes (P < 0.001), but the difference between the two treatments (adjusted for covariates) was not significant (P = 0.97). Both preparations of salbutamol produced a significant increase in oxygen saturation after 15 minutes (P < 0.05), while the difference between the two treatments (adjusted means) was not significant (P = 0.46). Peak flow measurements were available for 65 of the 99 patients. Both preparations of salbutamol produced highly significant (P < 0.001) improvements in PEFR at 15 minutes after treatment. The difference in peak flow rates between the two treatment groups (adjusted means) was not significant (P = 0.89). The study had a power of 0.8 to detect differences between treatments of 9% PEFR (percentage predicted), 0.8% oxygen saturation and 0.77 units of clinical score. CONCLUSIONS: A fixed dose of nebulised salbutamol is as efficacious as a salbutamol dose calculated for bodyweight in children with mild to moderate acute asthma.

Administration, Inhalation

The effect of age on oxygen desaturation during histamine inhalation challenge in normal infants.

Arterial oxygen saturation (SaO2) is usually measured during inhalation challenges in infants as desaturation has been demonstrated with provoked bronchoconstriction. We wished to examine whether measurement of SaO2 would provide a simple noninvasive indicator of respiratory function (RF) changes occurring during inhalation challenge in infants. Histamine inhalation challenges were performed longitudinally in 22 normal healthy infants at 4 and 26 weeks of age. RF was measured by calculating maximum forced expiratory flow at functional residual capacity (VmaxFRC) using the rapid thoracic compression technique. Airway responsiveness was assessed using histamine; the provoking concentration (PC) was that which caused a fall in VmaxFRC of at least 40% from baseline. The provocative concentration for an exact fall of 40% in VmaxFRC (PC40) from baseline was derived by linear interpolation. SaO2 was continuously monitored by pulse oximetry. One month old infants had higher SaO2 levels throughout the inhalation challenge in comparison to their SaO2 levels at 6 months of age. Significant falls in SaO2 were observed at the PC at both ages. However, at the age of 26 weeks the infants had greater median falls in SaO2 [PC, 4.5% (95%CI: 3.0, 7.0)] compared to the response at age 4 weeks [3.0% (95%CI: 1.0, 4.0) (P < 0.01)]. Median falls in VmaxFRC at the PC were not different between the ages. These results indicate an age-dependent discordance between airway and SaO2 response in healthy infants during histamine-induced bronchoconstriction.

Age Factors

The influence of a family history of asthma and parental smoking on airway responsiveness in early infancy.

BACKGROUND: Airway responsiveness to inhaled nonspecific bronchoconstrictive agents has been demonstrated in normal, healthy infants. However, it is unknown whether airway responsiveness is present from birth or if it develops as a result of subsequent insults to the respiratory tract. To investigate this question, we assessed airway responsiveness in 63 normal infants at a mean age of 4 1/2 weeks. METHODS: Respiratory function was measured with use of the partial forced expiratory flow-volume technique to determine the maximal flow at functional residual capacity (VmaxFRC). The infants inhaled nebulized histamine at sequentially doubled concentrations (0.125 to 8.0 g per liter), until a concentration was reached at which the VmaxFRC fell by 40 percent from the base-line value (PC40) or until a concentration of 8.0 g per liter was reached. We also assessed maternal serum levels of IgE, cord-serum levels of IgE, the infants' skin reactivity to several allergens, and the parents' responsiveness to histamine and obtained family histories of asthma and smoking. RESULTS: Airway responsiveness was increased in infants with a family history of asthma (n = 19; median PC40, 0.78 g per liter; 95 percent confidence interval, 0.44 to 1.15; P less than 0.01), parental smoking (n = 13; median PC40, 0.52 g per liter; 95 percent confidence interval, 0.43 to 5.40; P less than 0.05), or both (n = 20; median PC40, 0.69 g per liter; 95 percent confidence interval, 0.37 to 2.10; P less than 0.05), as compared with the infants with no family history of asthma or smoking. The infants with no family history of asthma or smoking had a median PC40 of 2.75 g per liter (95 percent confidence interval, 1.48 to 4.00). No significant relations were detected between the immunologic variables and the PC40 in the infants. CONCLUSIONS: This study indicates that airway responsiveness can be present early in life and suggests that a family history of asthma or parental smoking contributes to elevated levels of airway responsiveness at an early age.

Asthma

Time course of change in oxygen saturation and peak expiratory flow in children admitted to hospital with acute asthma.

The time course for recovery of the arterial oxygen saturation (SaO2) in acute childhood asthma is unknown. Serial measurements of SaO2 were made in 47 children during an acute attack of asthma that required admission to hospital. Adequate serial peak expiratory flow (PEF) measurements were possible in 28 children (mean age 8.3 years; group A), but not in the other 19 children (mean age 3.2 years; group B). Measurements of PEF and SaO2 were recorded twice daily before and 30 minutes after they had received salbutamol by nebuliser. Initial SaO2 values (mean (SD) %) were similar in groups A and B at 92.2 (3.5) and 92.4 (2.9). For the children in group A, PEF plateaued 36 hours after admission and SaO2 plateaued 12 hours later. Mean PEF improved after each dose of nebulised salbutamol during the first 36 hours, whereas mean SaO2 increased only after the first dose. SaO2 increased more rapidly in group B. Length of hospital stay was not related to initial SaO2 or PEF values. These data suggest that in children admitted to hospital for acute asthma arterial oxygen saturation is low at admission, recovers more slowly than airway function, reflects bronchodilatation with salbutamol only when SaO2 is low, and recovers more rapidly in younger children than in older children.

Acute Disease

Response of normal infants to inhaled histamine.

The age at which nonspecific bronchial hyperresponsiveness (BHR) is first seen in humans is unknown, though both genetic and environmental factors have been implicated in its development. The current study aimed to establish whether BHR to histamine can be demonstrated in normal infants. Twelve infants, mean age of 7.8 months (range, 3 to 18 months), were studied. None had any history of a previous significant respiratory illness. Respiratory function was monitored using the maximal flow at function residual capacity (VmaxFRC) obtained with the forced expiratory flow-volume technique. Histamine was inhaled in doubling concentrations from 0.125 to 8 g.L-1. A greater than 30% fall in VmaxFRC was considered a response. All infants responded to histamine, the geometric mean concentration for their response being 1.4 g.L-1. Associated transient changes for the group were an increase in respiratory rate (p less than 0.02) and a fall in SaO2 (p less than 0.001). Forced expiratory flow-volume curves were concave in all infants after the last dose of histamine. We speculate that humans are born with "bronchial hyperresponsiveness" and that genetic or environmental factors determine which infants lose it thereafter.

Bronchi