A quick guide for home use of inhalant medications.

The chronic and frequently recurring symptoms in an obstructive lung disease such as asthma often dictate a complex home treatment program for the child and family. In planning for discharge of an asthmatic child, the nurse assesses and evaluates a variety of treatment modalities.

Inhalation rate of sodium cromoglycate determines plasma pharmacokinetics and protection against AMP-induced bronchoconstriction in asthma.

We have investigated whether the inspiratory flow at which sodium cromoglycate (SCG) is inhaled influences the efficacy of SCG. Seven atopic asthmatic subjects (age 25 +/- 2 yrs) inhaled dry powder SCG from a Spinhaler on separate occasions at three flow rates, maximum (V1), 100 l.min-1 (V2), and 50 l.min-1 (V3), or placebo, according to a double-blind structured study. Thirty minutes after administration a bronchial provocation test was performed with adenosine 5'-monophosphate (AMP). Blood samples for measurement of plasma SCG concentration were taken and the area under the plasma concentration-time curve (AUC) calculated for each flow rate. Both inspiratory flow rate and AUC correlated significantly with the degree of protection afforded against AMP-induced bronchoconstriction (r = 0.73, p less than 0.001; r = 0.66, p less than 0.001). These findings indicate that the flow rate used to inhale powdered SCG is a major factor in determining the protective efficacy of this drug against bronchial challenge and therefore has important clinical implications.

[The role of inhalation chambers in the treatment of asthma]. / Place des chambres d'inhalation dans le traitement de l'asthme.

Inhalation chambers (spacers), interposed between the aerosol doser and the patient's mouth take 3 forms: lengthened tubes, large volume plastic sacs and conical chamber in the shape of a pear. Their chief advantages are: A greater proportion of the drug reaches the airways, as the deposition in the oropharynx is reduced. Co-ordination of lung and hand, a major obstacle to the correct use of aerosol-dosers, is no longer necessary.

Improvement in clinical asthma score and PaCO2 in children with severe asthma treated with continuously nebulized terbutaline.

We analyzed continuous nebulized terbutaline (CNT) therapy in 19 patients with 27 admissions for severe asthma and impending respiratory failure who failed to respond to our standard asthma protocol of methylprednisolone, aminophylline, and intermittently nebulized terbutaline. Terbutaline was administered by continuous face mask nebulization at a dose equaling the most frequent previous intermittent dose per hour (4 mg per hour). No patient with frank respiratory failure (i.e., PaCO2 greater than or equal to 60 torr, exhaustion, or coma) was studied. All patients improved, and therapy was stopped in a mean of 15.4 hours (range 3 to 37 hours). The average heart rate did not increase over baseline measurements through 24 hours of CNT. The mean clinical asthma score improved significantly during 8 hours, falling from 6.9 to 3.2 (p greater than 0.001). In 14 patients whose PaCO2 was greater than or equal to 39 torr (range 39 to 58 torr) and clinical asthma score was 6 or greater, PaCO2 decreased a mean of 11.7 torr during a mean of 8.1 hours. In six patients whose PaCO2 was 45 torr or greater at the start of CNT (mean 49, range 45 to 58 torr) and in whom we would have previously treated with intravenous isoproterenol, PaCO2 decreased a mean of 15 torr in an average of 8.7 hours. This preliminary study suggests that CNT is an effective therapy for severe asthma in children.

Aerosols--therapeutic use and delivery in childhood asthma.

Aerosol therapy has dramatically improved the lifestyle of the children with asthma, reflecting both the availability of more effective and safer drugs and alternative methods for their delivery. Inhaled treatment with bronchodilators, cromolyn, and inhaled corticosteroids, used singly or in various drug combinations, can control all but the most intractable asthmatic. It is essential that the inhalational device prescribed is appropriate for the child's age and that careful instructions are given as to optimal inhalation technique. Infants and young children with asthma should be given a trial of inhaled bronchodilators, recognizing the limitations this treatment may have in this age group.

Technique for aerosol deposition restricted to the nose in beagle dogs.

A method was developed for exposing the nasal cavity of beagle dogs to a radiolabeled aerosol without exposure of the remainder of the respiratory tract. Deposition efficiency, using a test aerosol of 2.0-micron particles of 99mTc-sulfur colloid delivered to the nose, was 15 +/- 2% (mean +/- SE) of inhaled activity. Gamma camera imaging showed that maximum deposition occurred in the anterior third of the nasal cavity, which contained 78 +/- 4% (mean +/- SE) of the total deposited radioactivity. The middle-third of the nasal cavity received 13 +/- 3% and the posterior third 9 +/- 2% of the deposited radioactivity. Aerosol deposition in regions of the respiratory tract below the larynx was not detectable.

Endotracheal drug administration in the critical care setting.

Administration of drugs through an endotracheal tube has been evaluated in a number of animal models. In addition, the technique has been utilized in humans as reported in several published cases. A review of endotracheal drug administration with emphasis on application to the critical care setting is presented.

Proper use of metered-dose inhalers: the role of the primary care physician.

We interviewed 50 primary care pediatricians and family physicians in order to assess their skills in instructing patients on the proper use of inhalers. Although 36 of them claimed that they were personally instructing their patients, major defects in their skills were observed. Whereas only 3 could personally perform all seven essential steps of an inhalation maneuver correctly, 20 failed on three to seven steps. Twelve failed on all steps. It is suggested that inadequate patient instruction by physicians may play a significant role in the incorrect use of inhalers by asthmatic children.

Tracheal and bronchoalveolar permeability changes in rats inhaling oxidant atmospheres during rest or exercise.

Permeability of tracheal and bronchoalveolar airways of rats was measured and used to examine the effects of inhaled oxidant-containing atmospheres. The atmospheres studied were (a) ozone (O3) at 0.6 ppm (1.2 mg/m3) or 0.8 ppm (1.6 mg/m3); (b) nitrogen dioxide (NO2) at 6 ppm (11.3 mg/m3) or 12 ppm (22.6 mg/m3); (c) O3 + NO2 at 0.6 ppm (1.2 mg/m3) and 2.5 ppm (4.7 mg/m3), respectively; and (d) a 7-component particle and gas mixture (complex atmosphere) representing urban air pollution in a photochemical environment. The rats were exposed for 2 h. The effects of exercise during exposure were evaluated by exposing additional groups in an enclosed treadmill. Exposure of resting rats to 0.8 ppm O3 increased tracheal permeability to DTPA and bronchoalveolar permeability to diethylenetriamine pentaacetate (DTPA) and bovine serum albumin (BSA) at 1 h after the exposure. Bronchoalveolar, but not tracheal, permeability remained elevated at 24 h after the exposure. Exercise during exposure to O3 increased permeability to both tracers in the tracheal and the bronchoalveolar zones, and prolonged the duration of increased permeability in the tracheal zone from 1 h to 24 h, and in the bronchoalveolar zone from 24 h to 48 h. Permeability in the tracheal and bronchoalveolar zones of rats exposed at rest to 6 or 12 ppm NO2 did not differ from controls. However, rats exposed during exercise to 12 ppm NO2 for 2 h developed a significant increase in tracheal and bronchoalveolar permeability to DTPA and BSA at 1 h, but not at 24 or 48 h, after exposure. Exposure at rest to 0.6 ppm O3 plus 2.5 ppm NO2 significantly increased bronchoalveolar permeability at 1 and 24 h after exposure, although exposure at rest to 0.6 ppm O3 alone increased bronchoalveolar permeability only at 1 h after exposure. Exposure to O3 + NO2 during exercise led to significantly greater permeability to DTPA than did exercising exposure to O3 alone. Resting rats exposed to a complex gas/aerosol atmosphere composed of the above O3 and NO2 concentrations, plus 5 ppm (13.1 mg/m3) sulfur dioxide (SO2) and an aerosol of insoluble colloidal Fe2O3 with an aerosol of manganese, ferric, and ammonium salts, demonstrated increased permeability at 1 and 24 h after exposure. Nitric acid vapor was formed in both the O3 + NO2 atmosphere and the complex gas/aerosol atmosphere.(ABSTRACT TRUNCATED AT 400 WORDS)

A new inhalation exposure system for the determination of inhaled doses in laboratory rats.

A new inhalation exposure system has been developed which allows the determination of inhaled doses of vapors and gases by laboratory rats. The system consists of saran bags connected to head-only exposure cylinders via one-way valves. One bag serves as the source of contaminant and another receives expired air. The exposure cylinders also serve as whole body plethysmographs. Up to three rats can be exposed concurrently to the same concentration of test material. The construction of the system and its use for inhalation exposures to a direct-acting radiolabeled carcinogen are described.