Asthma Inhalers - Outcomes of Intravenous and Inhaled Terbutaline in the Asthma Treatment
Basal values for the two days of the study were not significantly different for any of the indices measured. Both IV and inhaled routes of administration of terbutaline produced significant increases in FEVi, FVC, PEFR, MMFR, and MEF50. Both routes also produced a significant rise in VA and a fall in the slope of the alveolar plateau. These changes are shown graphically in Figures 3 and 4. The effect on the helium responsiveness of the MEF50 was variable, and although several patients showed increases, the mean responses of the whole group were not significantly different from the basal values. Both routes of administration also produced significant increases in effective pulmonary blood flow as measured by both single breath and rebreathing techniques. You may use ventolin, proventil, advair or flovent to treat asthma efficiently.
Using the single-breath method, Qeff showed a maximum increase from a basal value of 3.34 ± 1.56 L/min by 1.52 dr 0.88 L/min after inhaled terbutaline and from 3.38 ± 0.74 L/min by 1.54 ±: 0.92 L/min after IV terbutaline. The corresponding val ues for the rebreathing method were 3.26 db 0.75 L/min increasing by 0.59 ± 0.46 L/min after inhaled terbutaline and 3.51 it 0.75 L/min increasing by 0.71 =t 0.76 L/min after IV terbutaline. Effective blood flow per unit of ventilated lung volume (Qeff/VA) was derived by dividing individual blood flow values by their corresponding estimate of VA. This index increased significantly after terbutaline by both routes of administration for the singlebreath studies, but did not change significantly for the rebreathing estimates. Pulse rate increased significantly after IV terbutaline, but fell slightiy when the drug was given by inhalation. Only very small changes in blood pressure were observed and were not significantly different from basal values. The changes in effective pulmonary blood flow, pulse, and blood pressure are shown in Figure 5.
There were no significant differences between the effects of terbutaline by the IV and inhaled routes when comparisons were made at each of the four dosage intervals for any of the indices measured except pulse rate. The pulse rate was significantly higher after the IV route at every dose interval than for the inhaled route, when it actually fell slightly. Comparison of the maximal effects of the drug at any dose level between the two routes of administration again showed no significant difference for any of the variables measured except for pulse rate. Analysis of the results of individual patients failed to show any tendency for those with more severe airways obstruction within the group to show a greater effect produced by either route of administration.
The dose response relationship for each route of administration was analyzed by comparing the cumulative effects at each dose interval within that route. For the IV route most of the indices assessed were close to their maximal effect by the second dose, the further increments producing only small extra improvements that were usually not significant. An accumulated dose of 0.25 mg IV thus produced most of the effects obtainable by this route. For the inhaled route most indices showed continuing improvement right up to the last increment, which represented a total accumulated dose of 10 mg, ie, a plateau effect was not observed with this route of administration. Apart from mild tremor experienced by one patient on both days of the study, no other side effects were experienced by the patients.
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Figure 3. Comparison of increases in FEVj, FVC, and VA between intravenous and inhaled routes of administration. Mean±SE.
Figure 4. Comparison of the increases in MMFR and MEFS0 and effect on slope of alveolar plateau of two routes of administration. Mean 1 SE.
Figure 5. Comparison of effects on effective pulmonary blood flow, pulse and blood pressure between two routes of administration. Mean it 1 SE.