[The effects of dopexamine. Transpulmonary shunt volume in thoracic surgical procedures with one-lung respiration].
OBJECTIVE
To study the influence of dopexamine on pulmonary shunt and hypoxic pulmonary vasoconstriction during major thoracic surgery with one-lung ventilation (OLV).


METHODS
Prospective, randomised, placebo-controlled study.


METHODS
University hospital.


METHODS
Twenty adult patients undergoing elective pulmonary resection. ANAESTHESIA: General anaesthesia was performed using propofol, fentanyl, N2O and vecuronium. Volume-controlled ventilation was performed to maintain normocapnia over the whole investigation period. During OLV, the tidal volume was reduced and the respiratory rate was increased to avoid a peak airway pressure exceeding 40 cm H2O. Furthermore the FiO2 was increased to 1.0 and the external PEEP was removed during OLV.


METHODS
The patients received either dopexamine at 2 micrograms/kg/min (group A, n = 10) or 0.9% saline as control (group B, n = 10) after assessing the baseline values.


RESULTS
The following cardiorespiratory variables were recorded: Heart rate, mean arterial pressure and mean pulmonary arterial pressure. Cardiac output was measured by thermodilution using a continuous cardiac output thermodilution catheter. Arterial and mixed venous blood gas analysis were measured from simultaneously drawn samples. Cardiac index (CI), systemic vascular resistance index, pulmonary vascular resistance index, oxygen delivery index (DO2I), oxygen consumption index and the venous admixture were calculated using standard formula. Furthermore, pressure-flow-curves were constructed to analyse flow independent changes in the pulmonary vascular resistance. Data were recorded at the following times: After induction of anaesthesia in stable haemodynamics during two-lung ventilation (baseline values, T0), intraoperatively during one-lung ventilation (T1) and postoperatively after re-establishing two-lung ventilation (T2). Patients characteristics, data from the preoperative lung function testing and surgical procedures did not differ significantly between the groups. CI increased in the dopexamine group from 2.5 +/- 1.2 1.min-1.m-2 (T0) to 3.6 +/- 0.9 l.min-1.m-2 (T1) and 4.0 +/- 1.3 l.min-1.m-2 (T2). The course of the intrapulmonary right-to-left shunting did not differ between the groups. In the dopexamine-treated group the DO2I increased from 430 +/- 143 ml.min.m-2 (T0) to 652 +/- 255 ml.min.m-2 (T1) and 653 +/- 207 ml.min.m-2 (T2). Regarding the pressure-flow-curves there was no difference during OLV between the two groups indicating no major blocking effect of dopexamine on hypoxic pulmonary vasoconstriction.


CONCLUSIONS
It is concluded that dopexamine can be used to improve haemodynamics and oxygen delivery during thoracic surgery without increasing venous admixture during one-lung ventilation.
Müller
M
M
Abteilung für Anaesthesiologie und Operative Intensivmedizin, Klinikum der Justus-Liebig-Universität Giessen.
Sticher
J
J
Schindler
E
E
Scholz
S
S
Padberg
W
W
Jänich
S
S
Hempelmann
G
G
D000368:Aged; D000768:Anesthesia, General; D004298:Dopamine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D018491:Dopamine Agonists / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology*; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D019616:Thoracic Surgical Procedures / Q000379:methods*; D013990:Tidal Volume / Q000187:drug effects / Q000502:physiology; D014797:Vital Capacity / Q000187:drug effects / Q000502:physiology
D018491:Dopamine Agonists; C046318:dopexamine; D004298:Dopamine