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Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Conclusion

Pretrial and post-trial baseline hemodynamic values were essentially within normal limits but considerably below the optimal values empirically determined from critically ill postoperative survivors (Cl, 4.5 L/min/sq m; Do2, 600 ml/min/sq m; Vo2, 170 ml/min/sq m). Although about 75 percent of the postoperative patients achieved these goals with only therapy with fluids, all of the patients given dobutamine in the immediate postoperative period achieved these optimal goals during the titrations or in subsequent infusions of fluid and dobutamine. The relative effectiveness of both catecholamines on the disturbed circulation of the immediate postoperative state is of particular interest. The assumption here is that the lesion of peripheral circulatory postoperative shock is a maldistribution of flow from uneven vasoconstriction in which some metarterio-capillary networks are maximally constricted while others are wide open; this uneven flow pattern results in a high overall flow but inadequate oxygenation of tissues. It was assumed that the β2-adrenergic effect of dobutamine would be most clearly evident in these patients. Indeed, we found that dobutamine was most effective in the early postoperative period, and, moreover, the increases in Do2 and Vo2 were significantly greater after dobutamine than after dopamine. By contrast, the increases in Cl were smaller and not statistically significant after both dobutamine and dopamine in the elderly, in respiratory failure, in hyperdynamic states, and in patients with sepsis.
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Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Discussion

Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: DiscussionData in the Subsequent Postoperative Period and in Those with Complications
In the subset of nine patients who were studied more than three days after surgery, dopamine increased Cl by 0.71 ±0.45 (SD) from a baseline of 3.4 ±0.98 L/min/sq m, while dobutamine increased Cl by 0.79 ±0.67 from a baseline of 3.44 ±0.87 L/ min/sq m. There were appreciable changes in other variables which were not statistically significant, in part because of the small numbers in each group. Similarly, the responses to both agents were appreciable but not statistically significant in patients with sepsis, patients with respiratory or renal failure, patients who were over the age of 65 years, and hyperdynamic patients who had baseline cardiac indices greater than 4.5 L/min/sq m. Moreover, in these subsets, the responses to dobutamine were not significantly different from those to dopamine. comments
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Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Results

Analysis of Data
Differences in control values of the series as a whole, as well as diagnostic related groups, and values at the optimal dose of dobutamine were evaluated by Students f-test for paired distributions. Changes at each dosage were evaluated by ANOVA and the Newman-Keuls test.
Results
Analysis of the Series as a Whole

Hemodynamic and oxygen transport data at the pretrial control period, at each dosage level, and at a post-trial control period for dopamine and dobutamine are compared in Table 2. Figures 1 to 3 compare changes from their pretrial baseline values that occurred at each dosage level for the two agents. There were marked and significant increases in Cl, LCW, Do2, and HR, as well as reduced SVRI, as measured by ANOVA after administration of dobutamine. There were similar changes after dopamine that were not statistically significant by ANOVA; however, there were significant reductions in Pa02 and significantly increased Pv02 and Qsp after dopamine (Table 2). The increases in HR, Cl, and flow-related variables were somewhat greater after comparable dosages of dobutamine. Although Pa02 decreased after dopamine, this resulted in minimal changes in saturation, but significantly increased Qsp. Oxygen delivery, which is calculated as the product of Cl and Ca02, increased after administration of each drug in proportion to the increased flow. Dobutamine significantly increased Vo2 (Fig 3). The differences between the pretrial baseline measurements of dobutamine and dopamine were not appreciable nor statistically significant; the differences between the pretrial and posttrial measurements of both drugs were also insignificant and inappreciable. read

Data in the Immediate Postoperative Period
The data from 16 patients studied in the immediate postoperative period were analyzed separately in Table 3. There were marked and significant increases in HR, Cl, SI, Do2, and Vo2 after dobutamine administration in this subset of patients. The maximal Cl response to dobutamine regardless of dosage was 1.99 ±0.65 (SD) L/min/sq m, while the maximal response to dopamine was 0.95 ±0.29 L/min/sq m (p<0.01). The maximal response of Vo2 to dobutamine was 55 ±41 ml/min/ sq m, while the maximal response of Vo2 to dopamine was 29 ±28 ml/min/sq m.
Table 2—Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in the Entire Series

Drug and Variable PretrialBaseline Dosages jig/kg/min Post-trialBaseline
2.5 5.0 7.5 10
Dopamine
No. of subjects 25 25 20 18 15 19
MAP, mm Hg 92 ±17 92 ±18 93± 15 95± 15 93± 16 91 ±15
HR, beats per min 102 ±20 110 ±20 112 ±22 113 ±23 112 ±20 103 ±19
MPAP, mm Hg 23±8 23±8 23±6 21 ±7 23±6 23±8
PAWP, mm Hg 13 ±7 13 ±7 12 ±6 12 ±6 13 ±7 14 ±7
Cl, L/min/sq m 3.56 ±1.46 3.89 ± 1.45 4.15 ± 1.40 4.38 ±1.60 4.27±1.85 3.37 ±1.40
SI, ml/sq m 35.3 ±13.1 35.9± 12.6 38.0 ±12.6 40.0 ±15.2 39.2 ±17.4 33.3 ±13.2
LVSW, g*m/sq m 45.2 ±22.6 45.8 ±21.9 48.1 ±19.1 51.3 ±22.7 50.5±28.6 42.3 ±20.8
LCW, kg*m/sq m 4.5±2.4 5.0±2.4 5.3±2.1 5.7 ±2.5 5.5±2.9 4.2±2.1
SVRI, dyne*s/cm/sq m 1,950 ±586 1,761 ±519 1,684 ±510 1,654 ±484 1,662 ±509 2,066 ±609
PVRI, dyne*s/cm/sq m 233 ±150 232 ±115 214 ±111 184 ±79 211 ±105 250 ±171
Pa02, mm Hg 132 ±42 119 ±34 118 ±32 103 ±28 92±22t 130 ±42
Pv02, mm Hg 39 ±5 40±4 42±5 42±4t 40±4 38±4
Doa, ml/min/sq m 518 ±210 569 ±211 6Q3±207 630 ±232 611 ±254 502 ±191
Vo2, ml/min/sq m 136 ±35 138 ±33 147 ±46 143 ±48 136 ±33 138 ±33
Oxygen extraction, percent 28.2±7.6 26.5 ±7.0 25 3 ±6.2 23.8±5.9 23.9±5.5 29.1 ±6.4
Qsp, percent 14.5 ±9.0 17.0±9.6 16.7 ±8.7 21.1 ±10.6 24.0 ± 9.3t 12.9±6.7
Dobutamine
No. of subjects 25 25 25 24 20 20
MAP, mm Hg 93± 15 97 ±17 94± 16 94± 14 92± 14 90± 15
HR, beats per min 102 ±17 106 ±16 112 ±16 121 ±161: 126 ±17$ 106 ±19
MPAP, mm Hg 24±7 24±7 24±9 22±7 21 ±7 23±8
PAWP, mm Hg 15 ±6 15 ±6 14 ±6 12 ±5 11 ±5t 14 ±7
Cl, L/min/sq m 3.41 ±1.34 3.97 ±1.36 4.17± J..41 4.81±1.74t 4.79±1.38f 3.65± 1.38
SI, ml/sq m 33.6± 11.9 37.5 ±10.7 37.3± 11.6 40.2 ±13.5 37.8 ±8.5 34.4± 11.7
LVSW, g*m/sq m 43.3 ±18.9 50.0 ±18.4 48.1 ±19.3 52.1 ±21.2 47.6 ±15.5 42.7 ± 17.5
LCW, kg*m/sq m 4.4±2.0 5.3±2.2 5.4 ±2.3 6.2±2.7t 6.1±2.3 4.5±2.0
SVRI, dyne*s/cm/sq m 2,080 ±677 1,864 ±526 1,666 ± 498§ 1,467 ± 358§ 1,433 ±317§ 1,831 ±508
PVRI, dyne*s/cm/sq m 237 ±165 199 ±128 194 ±101 178 ±110 172 ±79 214 ±160
PaOs, mm Hg 125 ±37 121 ±38 121 ±38 115±41 112 ±42 126 ±43
PvQ2, mm Hg 38±5 39 ±4 39 ±5 40±5 41 ±7 39 ±5
Do,, ml/min/sq m 493 ±186 573 ±192 599 ±194 690± 248§ 693 ± 225§ 513 ±207
Vot, ml/min/sq m 139 ±40 147 ±43 151 ±38 161± 33t 158 ±49 133 ±30
Oxygen extraction, percent 29.8±7.2 26.6 ±5.3 26.4 ±6.9 24.9 ±6.2 24.0±7.2 27.8 ±7.2
Qsp, percent 13.1 ±6.3 14.5±6.9 15.1 ±6.7 16.8 ±7.3 19.1 ±10.5 15.1 ±9.3

Table 3—Comparison of Effects of Dopamine and Dobutamine in the Immediate Postoperative Period

Drug and Variable Baseline Dosage, p-g/kg/min
2.5 5 7.5 10
Dopamine
No. of subjects 13 13 11 9 7
MAP, mm Hg 92 ±13 98± 17 99± 14 97 ±14 99 ± 12t
HR, beats per min 104 ±22 113 ±20 117 ±22 116 ±27 112±21
MPAP, mm Hg 21 ±7 22 ±6 23±6 23±5 25±5
PAWP, mm Hg 13 ±5 13 ±6 13 ±6 14 ±7 14 ±7
Cl, L/min/sq m 3.31 ±1.07 3.72± 1.24 3.89± 1.15 3.89 ± 1.36 3.67 ±1.08
SI, ml/sq m 31 ±7 32 ±9 32 ±8 32 ±8 31 ±7
Do2, ml/min/sq m 467 ±177 522 ±200 540 ±198 527 ±223 472 ±104
Vo2, ml/min/sq m 130 ±33 140 ±42 153 ±51 133 ±57 121 ±36
Dobutamine
No. of subjects 13 13 13 13 12
MAP, mm Hg 98 ±14 103 ±13 99± 12 98± 10 95 ±11
HR, beats per min 105 ±15 110± 15 116 ±18 124 ±16f 127 ±18
MPAP, mm Hg 24 ±6 24±8 24±7 23±7 22±7
PAWP, mm Hg 15 ±6 14 ±6 14 ±5 12 ±5 ll±5t
Cl, L/min/sq m 3.12± 1.13 3.78 ±1.40 4.00±1.16t 4.41 ± 1.14f 4.55 ± 1.301*
SI, ml/sq m 28±8 34±7 34±8 36±7 36±7
Do2, ml/min/sq m 442 ±171 545 ±183 590 ±191 640 ± 1911 641 ±229
Vo2, ml/min/sq m 131 ±34 152 ±51 153 ±40 168 ± 39t 166 ±59

 

Figure 1. Changes in hemodynamic variables from baseline control values. Means (±SE) are shown for MAP, HR, Cl, SI, and LVSW, in response to dopamine (solid lines) and dobutamine (dashed lines) in dosages of 2.5μg/kg/min, 5μg/kg/min, 7.5μg/kg/min, and 10μg/ kg/m in.

Figure 1. Changes in hemodynamic variables from baseline control values. Means (±SE) are shown for MAP, HR, Cl, SI, and LVSW, in response to dopamine (solid lines) and dobutamine (dashed lines) in dosages of 2.5μg/kg/min, 5μg/kg/min, 7.5μg/kg/min, and 10μg/ kg/m in.

Figure 2. Changes in mean pulmonary arterial pressure. PAWP, SVRI, and PVRI, in response to dopamine (solid lines) and dobutamine (dashed lines) at various dosages.

Figure 2. Changes in mean pulmonary arterial pressure. PAWP, SVRI, and PVRI, in response to dopamine (solid lines) and dobutamine (dashed lines) at various dosages.

Figure 3. Changes in oxygen transport variables, PaOz, PvOa, Do2, Vo2, oxygen extraction, and Qsp, in response to dopamine (solid lines) and dobutamine (dashed lines) at various dosages.

Figure 3. Changes in oxygen transport variables, PaOz, PvOa, Do2, Vo2, oxygen extraction, and Qsp, in response to dopamine (solid lines) and dobutamine (dashed lines) at various dosages.

Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Materials and Methods

Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Materials and MethodsClinical Series
The study was approved by the institutions Human Subjects Review Committee, and each patient or the next of kin signed an informed consent. Studies were performed on 25 critically ill general surgical patients; Table 1 summarizes the salient clinical features. Each patient was given dopamine and dobutamine; the allocation of the first drug was by randomized order; subsequently, the other drug was given. Each drug was given in dosages of 2.5μg/kg/min, 5μg/kg/min, 7.5μg/kg/min, and 10μg/kg/min as tolerated. A minimum of 30 minutes and a maximum of two hours was allowed for equilibration between doses; post-trial baseline values were obtained 30 minutes after discontinuance of the last dose in each trial. Therapy with the drug was stopped if the HR increased over 140 beats per minute or the arterial pressure increased or fell inappropriately (>20 mm Hg). Data from the 16 patients who were studied in the immediate (0 to 72 hours) postoperative period were compared with the data from nine patients studied in later stages; the latter group also had complications such as sepsis, respiratory failure, renal failure, or other problems contributing to their critical illness and delayed recovery. www.cheap-asthma-inhalers.com
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Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients: Circulatory

The increased cardiac output was associated with reduced PAWP after dobutamine but with increased PAWP after dopamine. Improvement in tissue perfusion indicated by increased Do2 and Vo2 were demonstrated after various doses of dobutamine in critically ill general surgical patients; however, in patients with sepsis, Jardin et al found dobutamine reduced C(a-v)02 but did not significantly improve Vo2; dobutamine increased Qsp without PEEP but did not increase Qsp in patients with PEEP of 9±4 cm H20. In previous studies, we have empirically observed increased Cl, Do2, and Vo2 to median values of 4.5 L/min/sq m, 600 ml/min/sq m, and 170 ml/min/sq m, respectively, in surviving high-risk surgical patients during their early postoperative peak. In nonsurvivors, by contrast, the mean values of these three variables fell within the normal range during the first four days after surgery. Reading here
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Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical Patients

Comparison of Hemodynamic and Oxygen Transport Effects of Dopamine and Dobutamine in Critically Ill Surgical PatientsBoth dopamine, a naturally occurring catecholamine, and dobutamine, a synthetic catecholamine, have powerful positively inotropic, mild chronotropic, arrhythmogenic, and vascular effects. Dopamine raises arterial pressure by its a-adrenergic effect, but both catecholamines augment myocardial contractility by stimulation of (3-adrenergic receptors. Dobutamine is unique in that it has two stereoisomers: the (-)-isomer is more potent than the (H-)-isomer for the a-adrenergic receptor sites, while the reverse was found for the p-adrenergic receptors; moreover, the (-h)-isomer has some competitive a-adrenergic receptor blocking properties. In dogs, dobutamine increases coronary blood flow and myocardial oxygen delivery equal to, or in excess of, the increased oxygen required for positive inotropy. Most of the clinical literature on the effects of dobutamine have been concerned with cardiac patients with low cardiac output. http://cheap-asthma-inhalers.com/
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