Ten of the 28 patients recruited had reduced Cl immediately after separation from cardiopulmonary bypass (entry criteria) and received one of the two study drugs. Patients in the treatment groups were similar (p>0.2, Student’s t test) in terms of age, body size, and preoperative serum creatinine valve (Table 3). Although creatinine clearance tended to be higher in the dobutamine group, this difference was not significant (p=0.28, Student’s t test). Preoperative left ventricular ejection fraction in the group treated with dopexamine was 65 ±7 percent, equivalent to the dobutamine group (61 ±3 percent). asthma medications inhalers
OR Loading Phase Hemodynamics
The effects of starting dobutamine and dopexamine therapy on Cl, HR, MAP, and PCWP are shown in Figure 1. As shown in Table 4, both drugs elicited more than a 50 percent increase in Cl relative to measurements obtained immediately after separation from cardiopulmonary bypass (p<0.05), and this effect was maintained throughout the study period. The HR increased and PCWP decreased in both study groups following initiation of the drug therapy, but none of these changes was significant. Mean arterial pressure was not significantly altered by starting either drug therapy. The only significant difference between the two drugs during the OR loading phase of drug administration was a single measurement of PCWP (lower in the dopexamine group at 20 min after starting drug therapy despite further crystalloid infusion, p=0.05), and this change did not remain significant.
ICU Maintenance Phase Hemodynamics
Figure 2 demonstrates the same hemodynamic variables during the maintenance dosing period from 1 h after starting the study drug therapy through the remainder of the 24-h study period. The Cl remained elevated well above baseline values for both groups. The HR (after correction by esmolol infusions—see below), MAP, and PCWP did not change significantly during this phase of the study.
Table 3—Preoperative Patient Data
|PatientNo.||Age,yr||Weight,kg||BSA,m2||Serum Creatinine, mg/dl||Ejection Fraction,%||Creatinine Clearance, ml/min|
|X ± SEM||62 ±6||91 ±9||2.10±0.14||1.3±0.1||65 ±7||54 ±18|
|X ± SEM||66 ±3||73 ±7||1.83±0.11||1.0±0.2||61 ±3||91 ±27|
Table 4—Hemodynamic Variables (Mean ± SEM)
|Variable||Baseline||30 min||4 h||8 h||24 h|
|Dose, /ug/kg/min||1.9±0.6||1.4±0.2||1.2±0.2||1.2 ±0.2|
|Heart rate, beats/min||95 ±3||104 ±5||112±4||106 ±5||101 ±4|
|Cl, L/min/m2||2.3 ±0.1||3.5±0.1||3.4 ±0.3||3.2 ±0.2||3.4 ±0.2|
|MAP, mm Hg||75 ±8||78±5||76±5||73 ±3||81 ±4|
|PCWP, mm Hg||15 ± 1||13 ± 1||11 ± 1||10 ± 1||12 ±2|
|Dose, fig/kg/min||3.0 ±0.5||3.5 ±0.6||3.5±0.6||3.5±0.6|
|Heart rate, beats/min||91 ±3||99 ±6||107 ±5||100 ±5||98 ±5|
|Cl, L/min/m2||2.2 ±0.1||3.5 ±0.2||3.0 ±0.3||3.1 ±0.5||3.4±0.1|
|MAP, mm Hg||78±7||82 ±4||88 ±5||80 ±2||78±4|
|PCWP, mm Hg||13 ±2||10 ± 1||12 ± 1||12± 1||8± 1|
Figure 1. Effects of starting dopexamine (squares) and dobutamine (circles) on hemodynamic variables measured shortly after separation from cardiopulmonary bypass. Asterisk = change from baseline level (p<0.05); 8 = difference between drugs (p<0.05).
Figure 2. Effects of maintenance dopexamine (squares) and dobutamine (circles) on hemodynamic variables early during recovery from aortocoronary bypass grafting.