Peter Brand

Bio: Peter Brand is an academic researcher from RWTH Aachen University. The author has contributed to research in topics: Welding & Shielded metal arc welding. The author has an hindex of 17, co-authored 42 publications receiving 1072 citations.

Inhaling to mitigate exhaled bioaerosols

Abstract: Humans commonly exhale aerosols comprised of small droplets of airway-lining fluid during normal breathing. These “exhaled bioaerosols” may carry airborne pathogens and thereby magnify the spread of certain infectious diseases, such as influenza, tuberculosis, and severe acute respiratory syndrome. We hypothesize that, by altering lung airway surface properties through an inhaled nontoxic aerosol, we might substantially diminish the number of exhaled bioaerosol droplets and thereby provide a simple means to potentially mitigate the spread of airborne infectious disease independently of the identity of the airborne pathogen or the nature of any specific therapy. We find that some normal human subjects expire many more bioaerosol particles than other individuals during quiet breathing and therefore bear the burden of production of exhaled bioaerosols. Administering nebulized isotonic saline to these “high-producer” individuals diminishes the number of exhaled bioaerosol particles expired by 72.10 ± 8.19% for up to 6 h. In vitro and in vivo experiments with saline and surfactants suggest that the mechanism of action of the nebulized saline relates to modification of the physical properties of the airway-lining fluid, notably surface tension.

Lung deposition of inhaled α1-proteinase inhibitor in cystic fibrosis and α1-antitrypsin deficiency

Abstract: Individuals with alpha(1)-antitrypsin (AAT) deficiency and cystic fibrosis (CF) have a protease-antiprotease imbalance in their lungs, which leads to early onset progressive lung disease. Inhalation of AAT may restore protective levels in the lungs. This study aimed to determine the efficiency of delivering AAT using a novel inhalation device in subjects with AAT deficiency and CF compared with healthy subjects. In total, 20 subjects (six healthy, seven with AAT deficiency and seven with CF) inhaled approximately 70 mg of radiolabelled active AAT, with controlled breathing patterns adjusted to lung function. Post-inhalation, total and regional lung deposition and extrathoracic deposition of radiolabelled AAT were measured. Total lung deposition of AAT was approximately 70% of the filling dose. The magnitude of deposition was similar in all treatment groups, with no adverse effect on lung function or any influence of disease severity on total lung deposition. Inhalation with controlled breathing patterns using the AKITA(2) device (lung function adapted) leads to high total lung deposition regardless of the degree of lung function impairment. Delivery of large amounts of AAT was achieved in a short period of time. This device may be an ideal option for aerosol therapy.

Higher lung deposition with Respimat® Soft Mist™ Inhaler than HFA-MDI in COPD patients with poor technique

Abstract: Aerosols delivered by Respimat® Soft Mist™ Inhaler (SMI) are slower-moving and longer-lasting than those from pressurized metered-dose inhalers (pMDIs), improving the efficiency of pulmonary drug delivery to patients. In this four-way cross-over study, adults with chronic obstructive pulmonary disease (COPD) and with poor pMDI technique received radiolabelled Berodual® (fenoterol hydrobromide 50 μg/ipratropium bromide 20 μg) via Respimat® SMI or hydrofluoroalkane (HFA)-MDI (randomized order) on test days 1 and 2, with no inhaler technique training. The procedure was repeated on test days 3 and 4 after training. Deposition was measured by gamma scintigraphy. All 13 patients entered (9 males, mean age 62 years; FEV1 46% of predicted) inhaled too fast at screening (peak inspiratory flow rate [IF]: 69–161 L/min). Whole lung deposition was higher with Respimat® SMI than with pMDI for untrained (37% of delivered dose vs 21% of metered dose) and trained patients (53% of delivered vs 21% of metered dose) (pSign-Test].15; pANOVA < = 0.05). Training also improved inhalation profiles (slower average and peak IF as well as longer breath-hold time). Drug delivery to the lungs with Respimat® SMI is more efficient than with pMDI, even with poor inhaler technique. Teaching patients to hold their breath as well as to inhale slowly and deeply increased further lung deposition using Respimat® SMI.

Peripheral deposition of alpha1-protease inhibitor using commercial inhalation devices.

Abstract: Patients with hereditary alpha1-proteinase inhibitor (alpha1-PI) deficiency are at risk of developing lung emphysema. To prevent the development of this disease, alpha1-PI replacement therapy via inhalation may be a more convenient and effective therapy than the intravenous administration of the drug. In order to optimise this treatment approach, lung deposition of inhaled radiolabelled alpha1-PI (Prolastin) was studied using four different commercial inhalation devices (PARI-LC Star, HaloLite, and AKITA system in combination with LC Star and Sidestream) in six patients with alpha1-PI deficiency and mild-to-severe chronic obstructive pulmonary disease. The time required to deposit 50 mg of the Prolastin (5% solution) in the lung periphery was used as a measure for the efficiency of delivery. The time was calculated from measurements of total and peripheral lung deposition of the radiolabelled alpha1-PI. This time was shortest for the AKITA system (18-24 min) and significantly higher for the PARI-LC Star (44 min) and the HaloLite (100 min). The higher efficiency of drug delivery using the AKITA system is due to the fact that this device controls breathing patterns, which are optimised for each patient individually.

Number size distribution of fine and ultrafine fume particles from various welding processes.

Abstract: Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

Superspreading and the effect of individual variation on disease emergence

Abstract: Population-level analyses often use average quantities to describe heterogeneous systems, particularly when variation does not arise from identifiable groups. A prominent example, central to our current understanding of epidemic spread, is the basic reproductive number, R(0), which is defined as the mean number of infections caused by an infected individual in a susceptible population. Population estimates of R(0) can obscure considerable individual variation in infectiousness, as highlighted during the global emergence of severe acute respiratory syndrome (SARS) by numerous 'superspreading events' in which certain individuals infected unusually large numbers of secondary cases. For diseases transmitted by non-sexual direct contacts, such as SARS or smallpox, individual variation is difficult to measure empirically, and thus its importance for outbreak dynamics has been unclear. Here we present an integrated theoretical and statistical analysis of the influence of individual variation in infectiousness on disease emergence. Using contact tracing data from eight directly transmitted diseases, we show that the distribution of individual infectiousness around R(0) is often highly skewed. Model predictions accounting for this variation differ sharply from average-based approaches, with disease extinction more likely and outbreaks rarer but more explosive. Using these models, we explore implications for outbreak control, showing that individual-specific control measures outperform population-wide measures. Moreover, the dramatic improvements achieved through targeted control policies emphasize the need to identify predictive correlates of higher infectiousness. Our findings indicate that superspreading is a normal feature of disease spread, and to frame ongoing discussion we propose a rigorous definition for superspreading events and a method to predict their frequency.

Aerosol emission and superemission during human speech increase with voice loudness

Abstract: Mechanistic hypotheses about airborne infectious disease transmission have traditionally emphasized the role of coughing and sneezing, which are dramatic expiratory events that yield both easily visible droplets and large quantities of particles too small to see by eye. Nonetheless, it has long been known that normal speech also yields large quantities of particles that are too small to see by eye, but are large enough to carry a variety of communicable respiratory pathogens. Here we show that the rate of particle emission during normal human speech is positively correlated with the loudness (amplitude) of vocalization, ranging from approximately 1 to 50 particles per second (0.06 to 3 particles per cm3) for low to high amplitudes, regardless of the language spoken (English, Spanish, Mandarin, or Arabic). Furthermore, a small fraction of individuals behaves as "speech superemitters," consistently releasing an order of magnitude more particles than their peers. Our data demonstrate that the phenomenon of speech superemission cannot be fully explained either by the phonic structures or the amplitude of the speech. These results suggest that other unknown physiological factors, varying dramatically among individuals, could affect the probability of respiratory infectious disease transmission, and also help explain the existence of superspreaders who are disproportionately responsible for outbreaks of airborne infectious disease.

What the pulmonary specialist should know about the new inhalation therapies

Abstract: A collaboration of multidisciplinary experts on the delivery of pharmaceutical aerosols was facilitated by the European Respiratory Society (ERS) and the International Society for Aerosols in Medicine (ISAM), in order to draw up a consensus statement with clear, up-to-date recommendations that enable the pulmonary physician to choose the type of aerosol delivery device that is most suitable for their patient. The focus of the consensus statement is the patient-use aspect of the aerosol delivery devices that are currently available. The subject was divided into different topics, which were in turn assigned to at least two experts. The authors searched the literature according to their own strategies, with no central literature review being performed. To achieve consensus, draft reports and recommendations were reviewed and voted on by the entire panel. Specific recommendations for use of the devices can be found throughout the statement. Healthcare providers should ensure that their patients can and will use these devices correctly. This requires that the clinician: is aware of the devices that are currently available to deliver the prescribed drugs; knows the various techniques that are appropriate for each device; is able to evaluate the patient's inhalation technique to be sure they are using the devices properly; and ensures that the inhalation method is appropriate for each patient.