The effect of dopexamine on regional tissue oxygenation, systemic inflammation and amino acid exchange in major abdominal surgery

BACKGROUND: Beta-adrenergic agents are frequently used to improve cardiac performance in surgical and intensive care patients. Beta-adrenergic agents have metabolic and anti-inflammatory effects in addition to their cardiovascular effects. Splanchnic metabolic activity increases in response to surgery and inflammation. Dopexamine is believed to favor blood flow distribution to the splanchnic region. METHODS: We investigated the effect of dopexamine, started before major abdominal surgery, on postoperative patterns of systemic and regional blood flow, metabolic response, and markers of inflammation. Twenty-one patients undergoing major abdominal surgery were studied. All patients were stabilized preoperatively to predefined hemodynamic endpoints with fluids. After preoperative measurement of systemic and splanchnic oxygen transport and splanchnic lactate, glutamine and alanine exchange and blood levels of tumor necrosis factor (TNF) and interleukin-6 (IL-6), the patients were randomized to receive an infusion of dopexamine at 0.5 microg kg(-1) min(-1) (group 1) or 2.0 microg kg(-1) min(-1) (group 2) or placebo. Measurements were repeated at 6 h and 24 h after the end of the operation and the blood levels of cytokines also at 36 h postoperatively. RESULTS: Dopexamine evoked an increase in cardiac index preoperatively. Postoperatively, there was no difference between the groups in systemic and regional hemodynamics or oxygen transport: cardiac index, splanchnic blood flow and oxygen delivery increased similarly in each group. Accordingly, systemic oxygen extraction decreased. Glutamine, alanine and lactate exchange did not differ between the groups. The only metabolic change was an increased splanchnic uptake of alanine, which also was unaffected by dopexamine. There was no difference between the groups in TNF and IL-6 levels; TNF level did not change, while IL-6 level increased in response to surgery. CONCLUSIONS: Dopexamine, when added to a preoperative stabilization protocol with fluids, did not augment the postoperative hemodynamic response, and had no effect on postoperative metabolic and inflammatory responses.     

Supraceliac aortic cross-clamping and declamping. Effects of dopexamine and dopamine on systemic and mesenteric hemodynamics, metabolism and intestinal tonometry in a rat model

BACKGROUND: The effects of dopexamine and dopamine on mesenteric ischemia during reperfusion following aortic cross-clamping are not known. We determined intramucosal tonometric PCO2 and PCO2 gap using a rat model of supraceliac aortic cross-clamping and declamping. METHODS: Under pentobarbital and fentanyl anesthesia, 24 rats were surgically instrumented with arterial, right atrial, and portal venous catheters, ultrasonic flowprobes for measurements of abdominal aortic, superior mesenteric and carotid artery blood flow, and a pediatric tonometer for intestinal mucosal PCO2 measurements. Rats were randomized to receive a continuous infusion of dopexamine (10 x microg(-1) x kg(-1) x min(-1), n=8), dopamine (10 microg x kg(-1) x min(-1), n=8 ), or physiologic saline (control, n= 8), infused at a rate of 4 ml x kg(-1) x h(-1), administered throughout the experimental protocol. After 30 min of drug infusion, the aorta was cross-clamped at the supraceliac level for 30 min. Reperfusion following declamping was observed for 180 min. RESULTS: Intestinal tonometric PCO2 remained unchanged during drug treatment before aortic cross-clamping, increased similarly in all groups following declamping during early reperfusion, and recovered to baseline within 30 min of reperfusion. Dopexamine treatment was associated with higher lactate levels and increased heart rate (P<0.05) during aortic cross-clamping. CONCLUSIONS: 1) Mesenteric ischemia, determined by intestinal tonometric PCO2 and PCO2 gap, recovers within 30 min of reperfusion following 30 min of aortic cross-clamping irrespective of drug treatment and, 2) dopexamine induced higher lactate levels and increased heart rate during aortic cross-clamping and should be carefully analyzed for potentially adverse effects on cardiac function.     

Effects of Dopexamine on Lipid Peroxidation During Aortic Surgery in Pigs: Comparison with Dopamine

OBJECTIVE: We investigated the dose-related effect of dopexamine and dopamine on free radical production and lipid peroxidation estimated by MDA measurements in an ischaemia-reperfusion model of supraceliac aortic repair. DESIGN: Prospective, randomized, blinded experimental study. MATERIALS: Twenty-five healthy pigs. METHODS: All experiments were performed under general endotracheal anaesthesia. Supraceliac aortic cross clamping was performed in all pigs. The pigs were randomly assigned into five groups (n=5 in each group) and received a continuous intravenous infusion of normal saline (CTL), dopamine 2 microg kg(-1)min(-1) (dopa 2), dopamine 8 microg kg(-1)min(-1) (dopa 8), dopexamine 2 microg kg(-1)min(-1) (dopex 2), dopexamine 8 microg kg(-1)min(-1) (dopex 8). Cardiac output, mean arterial pressure, arterial blood gas analysis and blood sampling for plasma MDA measurements (to reveal lipid peroxidation) were recorded after induction of anaesthesia (baseline), 60 and 120 min after cross-clamping of aorta (ischaemia phase), and 60 and 120 min after restoration of flow (reperfusion phase). RESULTS: Dopexamine and dopamine at 8 microgkg(-1)min(-1) reduced MDA at 60 and 120 min after reperfusion. CONCLUSION: Dopexamine seems superior to dopamine in reducing oxygen free radicals and subsequent lipid peroxidation during reperfusion after supraceliac aortic cross clamping in pigs.     

Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+/-14.2 ml/min, placebo group LIMA flow at 26.1+/-16.3 ml/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+/-9.6 beats/min and placebo group at 71.1+/-7.6 beats/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may improve graft flow in the early post CABG period with minimal haemodynamic changes.     

Effects of dopexamine and volume loading on hemodynamics and oxygenation parameters in patients undergoing pulmonary resection

BACKGROUND: Pulmonary resection may result in a reduction in arterial oxygen pressure as well as in cardiac output. Since cardiac index, oxygen delivery, and oxygen consumption are considered as important determinants of patients' outcome, we evaluated the effects of dopexamine and volume loading on cardiopulmonary variables in patients undergoing pulmonary resection. METHODS: Forty adult patients undergoing pulmonary resection for lung or bronchial tumors were included in an open placebo-controlled study. The patients were selected according to a randomized sequence to group A (n=20) or group B (n=20). Dopexamine (2 microg x kg(-1) x min(-1)) was started when steady state conditions were achieved after induction of anesthesia in group A. Saline 0.9% was given as control (group B). Hemodynamic monitoring was performed using a pulmonary artery catheter. RESULTS: Dopexamine increased heart rate, cardiac output and oxygen delivery compared with control without increasing oxygen consumption during anesthesia and surgery. Furthermore, dopexamine was found not to alter the course of PaO2/FiO2 values. CONCLUSION: In patients undergoing pulmonary resection, dopexamine can be used perioperatively to increase cardiac index without decreasing the PaO2/FiO2 ratio.     

A randomized study to evaluate the effect of a perioperative infusion of dopexamine on colonic mucosal ischemia after aortic surgery

PURPOSE: Colonic ischemia after aortic surgery is associated with increased mortality and morbidity rates. This study was conducted as a single-center side arm to a multicenter, randomized, placebo-controlled study to evaluate the effect of dopexamine hydrochloride on its incidence. METHODS: Thirty patients, mean age 65.1 years (range, 46-84), undergoing elective infrarenal aortic surgery were entered. Preoperative hemodynamic and respiratory parameters were optimized. Patients were then randomly assigned to receive a perioperative infusion of dopexamine at 2 microg/kg per minute (n = 12) or 0.9% saline placebo (n = 18). All patients underwent colonoscopy and biopsy preoperatively and 1 week postoperatively. Specimens were assessed for evidence of mucosal ischemia, presence of mast cell tryptase, myeloperoxidase activity, and both the inducible and endothelial isoforms of nitric oxide synthase. RESULTS: There was no significant difference in perioperative fluid and blood requirements or hemodynamic and respiratory parameters between the two groups. However, there was significantly less evidence of mucosal ischemic changes in dopexamine-treated patients (n = 1) compared with placebo (n = 8) (P =.049). Furthermore, when preoperative biopsies were compared with those performed 1 week postoperatively, nine (50%) patients in the placebo group and two (16.7%) in the dopexamine group scored worse. Although there was no significant difference in inflammatory markers between the two groups, both mast cell tryptase and myeloperoxidase expression were increased in patients with histologic evidence of ischemia (P <.05). Furthermore, inducible nitric oxide synthase staining within the vascular (P =.001) and lamina propria (P <.05) components of the mucosa was also significantly greater. CONCLUSION: A perioperative dopexamine infusion affords significant histologic protection to colonic mucosa after aortic surgery.     

Renal tubular injury after infrarenal aortic aneurysm repair

OBJECTIVE: To investigate markers of tubular injury (glutathione-S-transferase [GST] isoforms) as early markers for renal damage in patients undergoing abdominal aortic aneurysm repair. DESIGN: Prospective study. SETTING: Regional teaching hospital. PARTICIPANTS: Eight consecutive patients undergoing elective infrarenal abdominal aortic aneurysm repair. INTERVENTIONS: All patients received a standard anesthetic technique including a dopamine infusion (3 microg/kg/min) but without supplemental renoprotective agents. Urine and blood samples were taken at induction, at 1 hour and 3 hours after limb reperfusion, and on days 1 and 2 postoperatively. Urine microalbumin and creatinine concentrations were measured using standard assays, and urine pi-GST and alpha-GST enzyme measurements were performed by a commercial immunoassay (Biotrin, Biotrin International Ltd., Co., Dublin, Ireland). MEASUREMENTS AND MAIN RESULTS: Five patients (63%) showed a postoperative elevation of serum creatinine (median increase from baseline, 35.4%; range, 8.3% to 50.6%) that was associated with significant elevations of urinary microalbumin-to-creatinine, alpha-GST-to-creatinine, and pi-GST-to-creatinine ratios soon after clamp removal. The remaining 3 patients showed no increase in serum creatinine or urine proteins. Peak alpha-GST-to-creatinine levels were different between the 2 groups. The peak levels of GST enzymes were significantly (r(2) > 80%) associated with the percent increase in serum creatinine from baseline. CONCLUSION: Urinary GST-to-creatinine ratios are a sensitive early biomarker for renal injury after infrarenal abdominal aortic aneurysm repair.     

Evaluation of dopexamine hydrochloride as a renoprotective agent during aortic surgery

Thirty-two patients undergoing elective infrarenal aortic surgery were randomly assigned to receive a perioperative infusion of either dopexamine hydrochloride at a rate of 2 g/kg/min (n = 15) or 0.9% saline solution as placebo (n = 17). Renal function was monitored by regular measurements of serum creatinine levels. There were significant mean percentage increases in serum creatinine (p < 0.001) at all time points up to 3 days postoperatively in the placebo group but only at 2 and 12 hours in the dopexamine group. It was concluded that dopexamine hydrochloride confers renal protection in patients undergoing aortic reconstruction.     

Comparison of systemic and renal effects of dopexamine and dopamine in norepinephrine-treated septic shock

OBJECTIVES: Vasopressor-induced vasoconstriction may compromise renal and splanchnic blood flow in patients with septic shock, resulting in secondary organ failures. The authors compared the effects of the vasodilatatory agent dopexamine against renal-dose dopamine and placebo in patients with norepinephrine therapy and septic shock, using 24-hour serum creatinine clearance (C(crea)) as a major endpoint. The primary hypothesis to be tested was that dopexamine is more effective than dopamine and that dopamine shows better effects than placebo regarding organ failures and C(crea). DESIGN: A prospective, randomized, controlled, double-blinded study. SETTING: Intensive care unit in a tertiary care university hospital. PARTICIPANTS: Sixty-one patients with septic shock defined according to established criteria. INTERVENTIONS: Patients received either dopexamine (2 microg/kg/min, n = 20), dopamine (3 microg/kg/min, n = 21), or placebo (n = 20). RESULTS: The trial groups were similar in terms of baseline characteristics. The authors found no significant differences among the dopexamine, dopamine, and placebo groups with regard to a comprehensive number of renal function parameters including C(crea) and organ-failure scores. There was a significant increase in heart rate after dopexamine infusion; other hemodynamic parameters remained unchanged in the dopexamine group. In a post hoc analysis that included only patients with renal impairment at study inclusion (n = 28), patients who received dopamine showed significant improvements in C(crea) when compared with placebo. Dopexamine was not effective in this subgroup. CONCLUSIONS: Dopexamine is no more effective than dopamine or placebo regarding renal function in patients with septic shock requiring norepinephrine. Both therapies do not influence organ-failure scores.     

The use of a remifentanil infusion for hemodynamic control during intracranial surgery.

Remifentanil is an extremely rapid and short-acting opioid analgesic which is effective in controlling acute stress responses during surgery. During neurosurgical anesthesia, laryngoscopy and intubation, application of the head holder, scalp incision, and the craniectomy can produce significant increases in mean arterial pressure (MAP). In this dose-response study, we evaluated the efficacy of a remifentanil infusion in maintaining hemodynamic stability during intracranial surgery under desflurane anesthesia. Forty-five patients were assigned randomly to one of the three remifentanil infusion groups. All patients received a standardized anesthetic induction consisting of midazolam, 2 mg IV, lidocaine 0.75 mg/kg IV, propofol 1.0 mg/kg IV, and remifentanil 0.5 microg/kg IV. Immediately after induction of anesthesia, a remifentanil infusion was started at 0.0625 microg x kg(-1) x min(-1) (Group 1), 0.125 microg x kg(-1) x min(-1) (Group 2), or 0.250 microg x kg (-1) x min(-1)(Group 3) according to a double-blinded study protocol. Maintenance of anesthesia consisted of desflurane 3% (end-tidal) in air/oxygen. If the MAP exceeded 80 mm Hg, a supplemental bolus of remifentanil, 0.5 microg/kg IV was administered, and when the MAP decreased below 65 mm Hg, the remifentanil infusion was discontinued temporarily. "Rescue" cardiovascular medications consisted of nitroprusside (100 microg IV) or phenylephrine (100 microg IV). Heart rate, systolic, diastolic, and MAP values, were recorded every minute for 20 min after each specific stimulus. The overall quality of the intraoperative hemodynamic control was evaluated by the attending anesthesiologist on a scale from 1 = poor to 5 = excellent. The overall quality of the hemodynamic control was superior in Group 2 compared with Group 1 (P < 0.05). Although the total dose of remifentanil administered during the study period did not differ among the three groups, Group 1 required significantly more supplemental boluses of remifentanil (66%-80%) than Groups 2 (13%-33%) and 3 (70% 13%), and the remifentanil infusion was discontinued more often in Group 3 (80%-93%) than in Groups 1 (0%-13%) and 2 (21%-40%). In conclusion, the recommended remifentanil infusion rate for controlling acute autonomic responses during neurosurgical anesthesia is 0.125 microg x kg(-1) x min(-1) when administered during a desflurane-based anesthetic. IMPLICATIONS: Compared with remifentanil 0.0625 microg x kg(-1) x min(-1) and 0.250 microg x kg(-1) x min(-1), a remifentanil infusion rate of 0.125 microg x kg(-1) x min(-1) provided more stable hemodynamic conditions during intracranial surgery under desflurane anesthesia.     

Monitoring of end-tidal carbon dioxide partial pressure changes during infrarenal aortic cross-clamping: a non-invasive method to predict unclamping hypotension

BACKGROUND: To assess the variations in end-tidal CO2 in response to aortic cross-clamping and the relationship with systolic arterial pressure (SAP) changes induced by unclamping. METHODS: Thirty-three patients undergoing infrarenal aortic abdominal aneurysm repair by aorto-aortic prothetic bypass were prospectively studied. All patients were anesthetized with i.v. midazolam (0.05 mg x kg(-1)), thiopentone (3-5 mg x kg(-1)), fentanyl (5 microg x kg(-1)), pancuronium (0.1 mg x kg(-1)) and the maintainance of anesthesia used was 1-1.5% end-tidal isoflurane and i.v. fentanyl. The perioperative management was standardized. End-tidal CO2 and SAP were measured 5 min before (Pre-XAA), 15 min after infrarenal aortic cross-clamping (XAA), 5 min before (Pre-UXAA) and immediately after unclamping (UXAA). RESULTS: A total of 16 (48.5%) from 33 patients presented decrease in SAP following aortic unclamping, and 13 out of these patients had arterial hypotension defined as SAP<90 mmHg. End-tidal CO2 variation (PreXAA-PreUXAA) induced by aortic clamping was correlated with SAP variation (PreUXAA-UXAA) induced by unclamping (r=0.763; P=0.0001). An end-tidal CO2 reduction above 15% after aortic cross-clamping was found to have a 100% sensitivity to detect a SAP decrease greater than 20% after unclamping, with a 100% specificity and a negative predictive value of 1.0. Complete aortic occlusion duration was not correlated to SAP unclamping variation (deltaSAP). Intraoperative characteristics (fluid loading, hematocrits, urinary output) were comparable, although blood loss was higher in patients experiencing deltaSAP>20%. CONCLUSIONS: End-tidal CO2 variation monitoring during aortic cross-clamping may provide a reliable and non-invasive method to predict unclamping hypotension. When the aortic clamp was released, systolic hypotension (>20%) occurred in those subjects who had a decrease in end-tidal CO2 greater than 15% during aortic cross-clamping.     

Blood loss and transfusion in elective abdominal aortic aneurysm surgery

BACKGROUND: Intraoperative blood loss and transfusion are known determinants of mortality and morbidity of elective abdominal aortic aneurysm (AAA) repair. The present study analysed the pattern of blood loss and transfusion and evaluated the risk factors of blood loss during open repair of infrarenal AAA. METHODS: Blood loss, transfusion and fluid replacement during elective open repair operation for patients with infrarenal AAA were correlated to demographic data, operative findings and procedural information. RESULTS: A total of 129 patients with a mean age of 71 years was analysed. The mean blood loss was 1000 +/- 887 mL (200-6000 mL). Blood transfusion, with a mean transfusion volume of 400 +/- 591 mL (0-3000 mL), was required in 46% of patients. Univariate analysis showed that bodyweight, renal impairment, low haemoglobin and platelet counts, iliac artery involvement, large aneurysm, bifurcated graft, large graft diameter, prolonged aortic clamp time and long operation time were associated with a higher blood loss. A haemoglobin level of <10.5 g/dL (relative risk (RR): 4.6), platelet count <130 x 10(9)/L (RR: 3.9), aortic clamp time >50 min (RR: 15), total operation time >200 min (RR: 11) and type of graft (RR: 3.5) were identified as independent determinants of blood loss on multivariate analysis. CONCLUSION: Intraoperative blood loss in elective infrarenal aneurysm surgery is influenced by patients' haematological parameters, distal involvement of aneurysm and degree of difficulty of operation.     

Effects of low dose ketamine before induction on propofol anesthesia for pediatric magnetic resonance imaging

BACKGROUND: We aimed to investigate effects of low dose ketamine before induction on propofol anesthesia for children undergoing magnetic resonance imaging (MRI). METHODS: Forty-three children aged 9 days to 7 years, undergoing elective MRI were randomly assigned to receive intravenously either a 2.5 mg x kg(-1) bolus of propofol followed by an infusion of 100 microg x g(-1) x min(-1) or a 1.5 mg x kg(-1) bolus of propofol immediately after a 0.5 mg x kg(-1) bolus of ketamine followed by an infusion of 75 microg x kg(-1) x min(-1). If a child moved during the imaging sequence, a 0.5-1 mg x kg(-1) bolus of propofol was given. Systolic and diastolic blood pressures, heart rate, peripheral oxygen saturation and respiratory rates were monitored. Apnea, the requirement for airway opening maneuvers, secretions, nausea, vomiting and movement during the imaging sequence were noted. Recovery times were also recorded. RESULTS: Systolic blood pressure and heart rate decreased significantly in the propofol group, while blood pressure did not change and heart rate decreased less in the propofol-ketamine group. Apnea associated with desaturation was observed in three patients of the propofol group. The two groups were similar with respect to requirements for airway opening maneuvers, secretions, nausea-vomiting, movement during the imaging sequence and recovery time. CONCLUSIONS: Intravenous administration of low dose ketamine before induction and maintenance with propofol preserves hemodynamic stability without changing the duration and the quality of recovery compared with propofol alone.     

The use of remifentanil for cesarean section in a parturient with recurrent aortic coarctation

PURPOSE: To illustrate the clinical utility of a short acting opioid (remifentanil) based general anesthetic for Cesarean section in a parturient with compromised cardiac function. CLINICAL FEATURES: A 23-yr-old primigravida, complicated by a recurrent aortic coarctation with an approximate 50% narrowing of the aortic arch, presented for elective Cesarean section at 37 wk gestational age. Initially asymptomatic, her clinical condition had deteriorated as the pregnancy progressed, with worsening episodes of mild chest pain and shortness of breath. A semi-elective Cesarean section under general anesthesia was planned at 37 wk to minimize the potential for aortic complications associated with the hemodynamic stress of labour. Remifentanil was infused at 0.05 to 0.1 microg x kg(-1) x min(-1) with good sedation and analgesia for the placement of invasive monitors. The infusion was increased to 0.2 microg x kg(-1) x min(-1) for induction, and combined with isoflurane 0.4 to 0.6% for maintenance of anesthesia. The patient maintained stable hemodynamics throughout and her trachea was extubated without difficulty at the end of the procedure. The newborn did not require tracheal intubation, mask ventilation or naloxone and was in excellent condition upon transfer to the well baby nursery. CONCLUSION: Remifentanil, when used as part of an opioid-based general anesthetic for Cesarean section, can provide maternal hemodynamic stability with minimal neonatal respiratory depression and should allow for immediate postoperative tracheal extubation of the mother.     

The efficacy of preemptive Milrinone or Amrinone therapy in patients undergoing coronary artery bypass grafting.

Acute deterioration in ventricular function and oxygen transport is common after cardiac surgery. We hypothesized that milrinone or amrinone may reduce their occurrence and catecholamine requirements and increase cellular enzyme levels in patients undergoing coronary artery bypass. In 45 patients, we randomly administered milrinone 50 microg/kg plus 0.5 microg x kg(-1) x min(-1) infusion for 10 h, amrinone 1.5 mg/kg plus 10 microg x kg(-1) x min(-1) infusion for 10 h, or placebo at release of aortic cross-clamp. Hemodynamic variables, dopamine requirement, and laboratory values were recorded. At the postoperative nadir, stroke volume index was higher in the Milrinone and Amrinone groups (mean +/- SD, 27.8 +/- 4.0 and 26.1 +/- 3.2 vs. 20.4 +/- 5.1 mL x min (-1) x m(-2) per beat, P < 0.0001), and oxygen transport index was higher (354.7 +/- 57.8 and 353.7 +/- 91.2 vs 283.0 +/- 83.9 mL. min(-1) x m(-2), P = 0.009). The postoperative dopamine requirement was less (6.6 +/- 2.7 and 6.8 +/- 2.6 vs 10.4 +/- 2.0 mg/kg, P < 0.008), and postoperative serum lactate, alanine and aspartate aminotransferase, lactate dehydrogenase, creatinine kinase, C-reactive protein, and glucose levels were less (P < 0.01). The mean postoperative heart rate was faster in the Milrinone group than in the Amrinone and Placebo groups (96.8 +/- 10.3 vs. 86.9 +/- 9.5 and 87.8 +/- 10.8 bpm, P < 0.01). Milrinone and amrinone administered preemptively reduce postoperative deterioration in cardiac function and oxygen transport, dopamine requirement, and increases in serum lactate, glucose, and enzyme levels, although milrinone may increase heart rate. IMPLICATIONS: Preemptive milrinone or amrinone administration before separation from cardiopulmonary bypass in cardiac surgical patients not only ameliorates postoperative deterioration in cardiac function and oxygen transport, but also reduces dopamine requirement and increases serum lactate, glucose, and cellular enzyme levels, although milrinone may increase heart rate.     

Remifentanil for modulation of hemodynamics in a patient undergoing laparoscopic resection of pheochromocytoma

The present report monitors the hemodynamic fluctuations in a 63 year-old female patient undergoing laparoscopic resection of right adrenal pheochromocytoma during remifentanil-based anesthesia. Anesthesia was induced with lidocaine 1 mg x kg(-1), propofol 3.5 mg x kg(-1), and cisatracurium 0.2 mg(-1) x kg(-1) and a remifentanil infusion was started at a rate of 1 ug.kg (-1) x min(-1). Anesthesia was then maintained with remifentanil infusion (0.5 microg(-1) x kg(-1) x min), sevoflurane 1-2% (end-tidal) in a mixture of air/oxygen (3:1), and a continuous infusion of cisatracurium. There were no significant changes of BP and HR following tracheal intubation or surgical incision. However, creation of pneumoperitoneum as well as tumor manipulation resulted in a dramatic increase of systolic BP and pulmonary artery pressure, associated with a decrease in cardiac output. These hemodynamic changes were unresponsive to an increase in the remifentanil infusion rate up to 1.5 ug.kg(-1) x min(-1), but were controlled by increasing the concentration of sevoflurane up to 6%, and by a nitroglycerin (NTG) infusion. Ten min after removal of the tumor, and despite discontinuation of the NTG infusion as well as a reduction in the remifentanil infusion and sevoflurane concentration, the BP decreased down to 64/43 mmHg. In conclusion, the present report shows in a patient undergoing laparoscopic resection of adrenal pheochromocytoma that remifentanil does not prevent the severe hypertensive episodes associated with intraperitoneal carbon dioxide insufflation or tumor manipulation. However, it can be titrated to prevent the hemodynamic reflex response to tracheal intubation and surgical stimulation.     

Influence of dopexamine on hemodynamics, intramucosal pH, and regulators of the macrocirculation and microcirculation in patients undergoing abdominal aortic surgery

OBJECTIVE: To investigate whether dopexamine hydrochloride beneficially influences splanchnic perfusion and regulators of the macrocirculation and microcirculation in patients undergoing surgery of the abdominal aorta. DESIGN: Prospective, blinded, and randomized study. SETTING: University-affiliated hospital. PARTICIPANTS: Twenty patients undergoing elective abdominal aortic surgery. INTERVENTIONS: The patients were randomized to one of two groups. In the dopexamine group (DOP, n = 10), dopexamine, 1 microg/kg/min, was started before surgery and continued for 24 hours. In the control group (COG, n = 10), patients received saline solution as placebo. Extensive hemodynamic monitoring was carried out using a pulmonary artery catheter, and intramucosal pH was measured using a gastric tonometer. From arterial blood samples, important regulators of the circulation were measured before dopexamine was administered (T0), before aortic clamping (T1), 20 minutes after aortic clamping (T2), after declamping the first leg (T3), at the end of surgery (T4), 1 hour postoperatively (T5), and 24 hours postoperatively (T6). MEASUREMENTS AND MAIN RESULTS: Heart rate increased significantly in DOP (63+/-16 to 84+/-18 beats/min). At T5, mean pulmonary artery pressure was significantly lower in DOP (15+/-6 mmHg) than in COG (22+/-6 mmHg). During aortic clamping, pulmonary capillary wedge pressure increased significantly in both groups. Cardiac index increased significantly from baseline only in the dopexamine patients. No significant differences between the groups were seen with regard to oxygenation parameters and intramucosal pH. Renin plasma levels increased significantly only in COG (46+/-32 to 99+/-55 microU/mL). Endothelin and atrial natriuretic peptide plasma levels showed no significant differences between the two groups. Atrial natriuretic peptide increased significantly only in DOP (366+/-171 pg/mL; COG, 159+/-71 pg/mL). Antidiuretic hormone, norepinephrine, and epinephrine plasma levels increased significantly from baseline in both groups, without showing significant differences between the groups. CONCLUSIONS: In patients undergoing abdominal aortic surgery, prophylactic perioperative administration of dopexamine hydrochloride produced effects on hemodynamics but without improving oxygenation and intramucosal pH. From the measured regulators of the circulation, only renin was beneficially affected.     

A case of heparin-induced thrombocytopenia associated with unexpected excessive argatroban anticoagulation after abdominal aortic aneurysm resection

We experienced excessive anticoagulation induced by argatroban for the treatment of heparin-induced thrombocytopenia (HIT). A 74-year-old man was scheduled for elective abdominal aortic aneurysm resection. During the surgery, both femoral arteries were found non-pulsatile requiring thrombectomy. The next day, second laparotomy was needed because of superior mesenteric artery occlusion. After the surgery, acute renal failure and hypoxemia continued with progressive thrombocytopenia necessitating frequent administration of platelet concentrates. Considering possibility of HIT, we stopped heparin and began argatroban. Due to his mild liver dysfunction, we initiated argatroban at 0.5 microg x kg(-1) x min(-1) one-fourth of standard initial dose, according to its drug information approved by FDA. Although expected APTT level was from 50 to 60 sec, it increased immediately up to 93 sec. Excessive anticoagulation continued more than 24 hours after cessation of argatroban and bleeding occurred from the tracheostomy site. When APTT decreased to the target range, we restarted argatroban and found the adequate dosage at 0.08 microg x kg(-1) x min(-1). After argatroban treatment, platelet count recovered immediately and no thromboembolism was observed. We recommend that argatroban should be initiated at a lower dosage than the dose shown in its drug information for HIT patients after cardiovascular surgery with frequent monitoring of APTT.     

Splanchnikusperfusion unter Dopexamin bei kardiochirurgischen Eingriffen

The present study investigates the effects of dopexamine on the splanchnic perfusion and the general circulation in patients undergoing coronary artery bypass grafting. METHODS: 34 Patients undergoing elective coronary artery bypass grafting were randomized to receive either dopexamine (1 microg/kg/min) or placebo (0,9% NaCl. ) Cardiac output was measured by thermodilution using a pulmonary artery catheter. Splanchnic blood flow was determined by constant infusion technique of indocyanine green dye (ICG) using a hepatic vein catheter. RESULTS: Under steady state conditions before surgery, dopexamine increased systemic oxygen supply and cardiac output by an increase in heart rate and stroke volume, with no increase in systemic oxygen demand. Before surgery dopexamine increased splanchnic blood flow together with an increase in cardiac output. After cardiopulmonary bypass dopexamine increased splanchnic perfusion without a concomittant rise in cardiac output. CONCLUSION: These results provide evidence that dopexamine improves splanchnic blood flow in patients with coronary artery disease before and after pulmonary bypass without impairment of general hemodynamics.