Metered Dose Inhalers for Bronchodilator Delivery in Intubated, Mechanically Ventilated Patients· ltner C. Gay, M.D., F.C.C.P.; Hemant G. lbtel, M.D.;
Steven B. Nelson, M.S.; Bernard Gilles, R.R.T.; and RolfD. Hubmayr, M.D., F.C.C.P.
We determined the relative efficacy of two bronchodilator aerosol delivery methods in 18 intubated mechanicalJy ventilated patients with airways obstruction. Two treatment arms, consisting of a1buterol 270 IJ.g (three puffs) from a metered dose inhaler and a1buterol 2.5 mg from a saline solution nebulized with an updraft inhaler, were compared in a single blind, randomized crossover design. Pulmonary fuuction was evaluated using an interrupter technique. Changes in passive expiratory Row at respiratory system recoil pressures between 6 and 10 cm HsO provided the therapeutic endpoints. Paired measurements were made befure and 30 minutes after drug delivery. The MDI and NEB resulted in similar improvements in iso-recoil Row
(mean increase for both groups=O.1 Us). Treatment sequence, severity of obstruction, and bronchodilator responsiveness had no effect on relative efficacy. A1buterol caused a small but signi6cant increase in heart rate that was similar following both delivery methods. We conclude that bronchodilator aerosol delivery with metered dose inhalers provides a viable alternative to nebulizer therapy in intubated mechanically ventilated patients and may result in a cost savings to hospitals and patients.
aerosols play an integral role in the Bronchodilator treatment of patients with airways obstruction.
in the incidence of adverse cardiovascular side effects directly attributable to the delivery system; and (3) in our practice setting, the cost per treatment is lower when using MDI.
Aerosols can be generated from a solution with a nebulizer or administered directly with a metereddose inhaler. In ambulatory, as well as nonintubated, hospitalized patients, these two delivery modes have resulted in equivalent degrees of bronchodilation, whereby large differences in cost and convenience favor the use of MDI.I-6 The responsiveness of patients to bronchodilators is usually assessed from spirometric measurements of maximal expiratory flow. Since spirometry is not a feasible technique in intubated, mechanically ventilated patients, the efficacy of MDI in this population has not yet been established. We have previously shown that nebulized metaproterenol increases isorecoil flow in many ventilator-dependent patients and have, thereby, demonstrated that bronchodilator response testing is possible in an intensive care unit environment." In this study, we have examined the following three hypotheses: (1) albuterol delivered either as a nebulized solution in an updraft inhaler or via a metered dose inhaler results in equivalent degrees of bronchodilation; (2) there is no difference -From the Department ofInternal Medicine and Thoracic Diseases, Critical Care Service, Mayo Graduate School of Medicine, Rochester, MN. This study was supported by grant HL 38107. Manuscript received March 26; revision accepted July 11. Reprint requests: Dr. Hubmayr, S3 Plummer; Mayo Clinic, Rochester; MN55905
(Cheat 1991; 99:66-71) MDI=metered dose inhaler; NEB=nebulizer; SEV=static equilibrium volume
METHODS
Twenty adult ventilator-dependent patients, in whom the physician in charge had ordered bronchodilator aerosols for suspected airways obstruction, consented to be studied. All patients were clinically stable, as indicated by the absence of hypotension, tachycardia, and/or cardiac arrhythmias. Two patients were excluded from this report, because our tests did not confirm a diagnosis of airways obstruction. Measurement Techniques
M
Airway pressure (Pao) and How were measured at the oral end of the endotracheal tube (MicroswitchIHoneywell pressure transducer; Hans Rudolph pneumotachograph), and sampled at a rate of 50 Hz with a dedicated computer. Recordings were made during stepwise deBations of the relaxed respiratory system (Hans Rudolph interrupter valve) at lung volumes between end inspiration and static equilibrium volume. After each maneuver, Pa
Steven B. Nelson, M.S.; Bernard Gilles, R.R.T.; and RolfD. Hubmayr, M.D., F.C.C.P.
We determined the relative efficacy of two bronchodilator aerosol delivery methods in 18 intubated mechanicalJy ventilated patients with airways obstruction. Two treatment arms, consisting of a1buterol 270 IJ.g (three puffs) from a metered dose inhaler and a1buterol 2.5 mg from a saline solution nebulized with an updraft inhaler, were compared in a single blind, randomized crossover design. Pulmonary fuuction was evaluated using an interrupter technique. Changes in passive expiratory Row at respiratory system recoil pressures between 6 and 10 cm HsO provided the therapeutic endpoints. Paired measurements were made befure and 30 minutes after drug delivery. The MDI and NEB resulted in similar improvements in iso-recoil Row
(mean increase for both groups=O.1 Us). Treatment sequence, severity of obstruction, and bronchodilator responsiveness had no effect on relative efficacy. A1buterol caused a small but signi6cant increase in heart rate that was similar following both delivery methods. We conclude that bronchodilator aerosol delivery with metered dose inhalers provides a viable alternative to nebulizer therapy in intubated mechanically ventilated patients and may result in a cost savings to hospitals and patients.
aerosols play an integral role in the Bronchodilator treatment of patients with airways obstruction.
in the incidence of adverse cardiovascular side effects directly attributable to the delivery system; and (3) in our practice setting, the cost per treatment is lower when using MDI.
Aerosols can be generated from a solution with a nebulizer or administered directly with a metereddose inhaler. In ambulatory, as well as nonintubated, hospitalized patients, these two delivery modes have resulted in equivalent degrees of bronchodilation, whereby large differences in cost and convenience favor the use of MDI.I-6 The responsiveness of patients to bronchodilators is usually assessed from spirometric measurements of maximal expiratory flow. Since spirometry is not a feasible technique in intubated, mechanically ventilated patients, the efficacy of MDI in this population has not yet been established. We have previously shown that nebulized metaproterenol increases isorecoil flow in many ventilator-dependent patients and have, thereby, demonstrated that bronchodilator response testing is possible in an intensive care unit environment." In this study, we have examined the following three hypotheses: (1) albuterol delivered either as a nebulized solution in an updraft inhaler or via a metered dose inhaler results in equivalent degrees of bronchodilation; (2) there is no difference -From the Department ofInternal Medicine and Thoracic Diseases, Critical Care Service, Mayo Graduate School of Medicine, Rochester, MN. This study was supported by grant HL 38107. Manuscript received March 26; revision accepted July 11. Reprint requests: Dr. Hubmayr, S3 Plummer; Mayo Clinic, Rochester; MN55905
(Cheat 1991; 99:66-71) MDI=metered dose inhaler; NEB=nebulizer; SEV=static equilibrium volume
METHODS
Twenty adult ventilator-dependent patients, in whom the physician in charge had ordered bronchodilator aerosols for suspected airways obstruction, consented to be studied. All patients were clinically stable, as indicated by the absence of hypotension, tachycardia, and/or cardiac arrhythmias. Two patients were excluded from this report, because our tests did not confirm a diagnosis of airways obstruction. Measurement Techniques
M
Airway pressure (Pao) and How were measured at the oral end of the endotracheal tube (MicroswitchIHoneywell pressure transducer; Hans Rudolph pneumotachograph), and sampled at a rate of 50 Hz with a dedicated computer. Recordings were made during stepwise deBations of the relaxed respiratory system (Hans Rudolph interrupter valve) at lung volumes between end inspiration and static equilibrium volume. After each maneuver, Pa
