Biomedical subjects

Harm Tiddens

Publications and source records attributed to Harm Tiddens.

5 recordsLinked to original sources

PubMed2006

Aerosol therapy by pressured metered-dose inhaler-spacer in sleeping young children: to do or not to do?

UNLABELLED: One third of young children are distressed during inhalation therapy. It has been suggested that administration during sleep could be a good alternative for these children. A laboratory study in our department using an infant upper airway model showed significantly higher lung doses from a pressured metered-dose inhaler (pMDI)-spacer for sleep-breathing patterns compared with wake-breathing patterns. OBJECTIVE: We set up a daily life study to investigate the feasibility of aerosol administration by means of pMDI-spacer in sleeping young children. DESIGN: Over a period of 3 weeks, 30 children (age range, 6 to 23 months) with recurrent wheeze daily inhaled 1 puff of budesonide aerosol (200 mug) while awake and 1 puff during sleep. Filters positioned between the chamber and the facemask trapped the budesonide aerosol. Parents scored the child's asthma symptoms, degree of cooperation, and feasibility of administration on diary cards. RESULTS: In 69% of the sleep administrations, the children woke up, and in 75% of these cases the children were distressed. The mean filter dose (expressed as the percentage of the nominal dose) while awake was 47%, and during sleep it was 16% (p = 0.007). The median within-subject dose variability while awake was 50%, and during sleep it was 110% (p = 0.007). CONCLUSION: Aerosol administration by means of pMDI-spacer during sleep offers no advantage and is not a feasible treatment option in most young children.

Administration, Inhalation↗

PubMed2005

Pharmacodynamics of tobramycin in patients with cystic fibrosis.

Relationships between pharmacodynamic indices (PI), such as the area under the concentration-time curve (AUC)/MIC ratio and time > MIC (T(>MIC)), and efficacy have been described for antimicrobial drugs. The use of these quantitative relationships may increase the power to demonstrate significant effects of drugs, obviating the need to include large numbers in comparative trials. Patients with cystic fibrosis (CF) hospitalized for treatment of an infectious exacerbation due to Pseudomonas aeruginosa were eligible for the study. They received tobramycin 3.3 mg/kg tid as initial therapy in combination with ticarcillin 125 mg/kg qid. Blood samples were drawn at t = 0-8 h after infusion. Pharmocokinetic parameters and PI were calculated for every individual and correlated to the relative improvement in forced expiratory volume during the first second (FEV1) and forced vital capacity (FVC) between pretreatment and days 9-11 as a measure of efficacy. The 3 PI fAUC/MIC, f Peak/MIC, and T(>MIC) of tobramycin showed a significant correlation with effect and was the highest for the fAUC/MIC relationships with FEV1 and FVC as determined both by the Emax model as well as Spearman correlations (r = 0.77, P = 0.002 and 0.58, P = 0.036 for FEV1 and FVC). Pharmacokinetic parameters AUC and Peak as such showed no significant correlation with effect, nor did the MIC values. There is a significant relationship between PI of aminoglycosides and efficacy parameter (increase in FEV1 and FVC) in patients with CF. This study demonstrates the applicability of pharmacodynamic relationships in determining efficacy of antimicrobial therapy, by demonstrating a strong PI-effect relationship in a group of only 13 patients.

Adolescent↗

PubMed2005

Aerosol delivery to young children by pMDI-spacer: is facemask design important?

This study aimed at identifying in a daily-life setting the influence of facemask design on drug delivery via a spacer to young children. In a 4-week randomized crossover study, 24 children (7-23-months old) with recurrent wheeze tested the AstraZeneca, Galemed, and Hans Rudolph facemask combined with the NebuChamber at home. Each mask was tested twice daily for seven consecutive days. Filters positioned between the NebuChamber and facemask trapped the budesonide aerosol (200 microg, Pulmicort). Parents were asked to score the child's degree of cooperation during administration on diary cards. The administration procedure was evaluated through video recordings. Mean filter dose (standard deviation (s.d.)), expressed as % of nominal dose, was 39% (14), 47% (12), and 42% (11) for the AstraZeneca, the Galemed and the Hans Rudolph mask, respectively. Irrespective of the degree of cooperation, the Galemed mask gave significantly higher mean filter doses than the other masks (level of significance) (p < 0.045). Median (range) within-subject dose variability, expressed, as coefficient of variation (CV), was 37% (19-255), 32% (9-114), and 30% (9-115) for the AstraZeneca mask, the Galemed mask and the Hans Rudolph mask, respectively, not significant. Dose variability increased with decreasing cooperation for all three masks (p = 0.007). Drug delivery to young children with recurrent wheeze by means of the NebuChamber can be enhanced using the Galemed facemask. Dose variability seems to be independent of facemask design but mainly depends on cooperation.

Administration, Inhalation↗

PubMed2004

Matching the device to the patient.

Aerosol therapy is complex, especially in young children, and can only succeed when the physician has detailed knowledge about: aerosol characteristics of the various aerosol delivery systems; the pathophysiology of the lung disease; the skills of the patient in various age groups. Only when this knowledge is available the appropriate delivery device for the child can be selected and the proper instructions can be given. Most aerosol delivery devices are not primarily developed for use in children. Particle size characteristics of most delivery systems are suboptimal for children since they deliver only a low mass of extra fine aerosol particles.

Administration, Inhalation↗

PubMed2004

Inhaled antibiotics.

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Administration, Inhalation↗