Nebulizer breathing pattern

O Callaghan, C., White, J., Jackson, J., Barry, P. W., and Kantar, A. (2005), Delivery of nebulized budesonide is affected by nebulizer type and breathing pattern, J. Pharm. Pharmacol, 57,787-790. 

Nebulizers fitted with a T-mouthpiece have an unrestricted flow of ambient air passing through the nebulizer output, supplying inhaled air flow, which effectively increases drug output. In vented nebulizers, the inhaled air must flow through the droplet production region. Therefore, the breathing pattern of the patient has an effect on the aerosol characteristics produced by such devices. The delivery efficiency of... 

The AeroEclipse (Monaghan/Trudell International) shown in Fig. 9, is a nebulizer powered by compressed air, which can be operated in both continuous nebuli-zation and breath-actuated modes. The nebulizer was characterized, in vitro, using different breathing patterns, with either continuous nebulization or breath-actuated nebulization. A piston pump was used to... 

Nebulized aerosol is introduced to the patient by compressed air, either from a constant source or from a device known as intermittent positive-pressure ventilator. Nebulized aerosols rely less on the patient s own breathing pattern. Under some circumstances the dose administered to the patient by nebulizer is inconsistent or unpredictable. In a hospital setting, the aerosol administration can be supervised by qualified individuals. Home administration is not always supervised, and there is, therefore, a potential for misuse. 

Newman SP, Woodman G, Clarke SW. Deposition of carbenicillin aerosol in cystic fibrosis effects of nebulizer system and breathing pattern. Thorax 1988, 43, 318-322. 

Several models have been proposed to calculate deposition of particles within the respiratory tract of children, but these remain highly controversial because of the assumptions about the breathing pattern and structure of the upper and lower respiratory tract that have been made (223,224). Drug delivery to the very young child is enhanced by the fact that infants with PlFs below 100 mL/s (6 L/min— generally those less than 6 months of age) will inhale pure aerosol from a nebulizer, whereas air which does not contain aerosol will be entrained in older subjects, resulting in some dilution of the delivered dose (Fig. 11) (221,225). 

Task Group on Lung Dynamics. Deposition and retention models for internal dosimetry of the human respiratory tract. Health Phys 1966 12 173-207. Findeisen W. Uber das Absetzen kleiner in der Luft suspendierten Tailchen in der menslichen Lunge bei der Atmung. Pflilgers Arch Ges Physiol 1935 236 367-379. Newman SP, Woodman G, Clarke SW. Deposition of carbeniciUin aerosols in cystic fibrosis effects of nebulizer system and breathing pattern. Thorax 1988 43 318-322. 

Figure 4 Cartoon depicting technique for quantification of nebulizer output and measurement of deposition. On the left, a patient inhales nebulized particles via a Y piece. The exhalation filter captures exhaled particles. On the right, the same patient performs a similar maneuver. The inhaled mass filter captures particles that would have been inhaled. Differences between filters measure deposition. Breathing pattern can be monitored using a pneumotachograph represents the sum of minute ventilation plus nebulizer flow leaving the expiratory arm of the Y piece). (From Ref. 9.)...

Other types of nebulizer modifications are linked to the breathing pattern and therefore can affect output. These include breath actuation, in which the... 

Figure 22 Importance of nebulizer choice in aerosol delivery via mechanical ventilation. The breathing pattern was fixed and inhaled mass (%) is plotted against time for four different nebulizers. (From Ref. 27.)...

Nikander K, Deyner J, Smaldone GC. Effects of equipment dead space and pediatric breathing patterns on inhaled mass of nebulized budesonide. J Aerosol Med 1999 12 67-73. 

A simulated inhalation flow fixed at 15 L/min was selected as a standard test condition. This total inhalation flow is positioned (operated by pump or vacuum line) in the patient s mouth it is made up of both the primary flow of compressed air through the jet nebulizer (e.g., 8 L/min) the remainder (e.g., 7 L/min) drawn from the ambient environment (Fig. 14). A flow at 15 L/min was chosen for two reasons. First, 15 L/min represents the midpoint flow of the standardized breathing pattern (15 breaths per minute x 500 mL) as well as approximating the average inhalation flow of an adult during tidal breathing. 

Denyer J. Breathing patterns in adult patients. J Aerosol Med 1997 10(1) 99. Stapleton KW, Finlay WH. Errors in characterizing nebulized particle size Distributions with cascade impactors. J Aerosol Med 1998 ll(Suppl l) 80-83. 

Pattern Tidal volume (ml) Breathing frequency (1/min) Nebulization... 

For the same pattern of breathing, the quantity of aerosol inhaled over time is strongly dependent on the type of nebulizer utilized. As shown in Fig. 5, the AeroTech II produces aerosol at a rate approximately six times that of the Respirgard II (the difference in slopes). The plateau of each curve indicates the point at which the nebulizer runs dry and defines the amount of drug inhaled by the patient. For the AeroTech II, approximately 20% of the nebulizer charge is ultimately inhaled, versus 11% for the Respirgard II (9). 

---