Dopexamine hydrochloride does not modify hemodynamic response or tissue oxygenation or gut permeability during abdominal aortic surgery

The Effect of inotropes and vasopressors on mortality: a meta-analysis of randomized clinical trials

BACKGROUND

Inotropes and vasopressors are frequently administered to critically ill patients in order to improve haemodynamic function and restore adequate organ perfusion. However, some studies have suggested a possible association between inotrope administration and increased mortality. We therefore performed a meta-analysis of randomized trials published in the last 20 yr to investigate the effect of these drugs on mortality.

METHODS

BioMedCentral, PubMed, Embase and the Cochrane Central Register were searched (all updated April 8th, 2015). Inclusion criteria were: random allocation to treatment, at least one group receiving an inotropic or vasopressor drug compared with at least one group receiving a non-inotropic/vasopressor treatment, study published after 1st January 1994, and systemic drug administration. Exclusion criteria were overlapping populations, studies published as abstract only, crossover studies, paediatric studies and lack of data on mortality.

RESULTS

A total of 28 280 patients from 177 trials were included. Overall, pooled estimates showed no difference in mortality between the group receiving inotropes/vasopressors and the control group [4255/14 036 (31.7%) vs. 4277/14 244 (31.8%), risk ratio=0.98 (0.96-1.01), P for effect=0.23, P for heterogeneity=0.30, I2=6%]. A reduction in mortality was associated with inotrope/vasopressor therapy use in settings of vasoplegic syndromes, sepsis and cardiac surgery. Levosimendan was the only drug associated with improvement in survival. Subgroup analysis did not identify any groups with increased mortality associated with inotrope/vasopressor therapy.

CONCLUSIONS

Our systematic review found that inotrope/vasopressor therapy is not associated with differences in mortality in the overall population and in the majority of subsettings.

Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Clinical review: Goal-directed therapy-what is the evidence in surgical patients? The effect on different risk groups

Patients with limited cardiac reserve are less likely to survive and develop more complications following major surgery. By augmenting oxygen delivery index (DO₂I) with a combination of intravenous fluids and inotropes (goal directed therapy (GDT)), postoperative mortality and morbidity of high-risk patients may be reduced. However, although most studies suggest that GDT may improve outcome in high-risk surgical patients, it is still not widely practiced. We set out to test the hypothesis that GDT results in greatest benefit in terms of mortality and morbidity in patients with the highest risk of mortality and have undertaken a systematic review of the current literature to see if this is correct. We performed a systematic search of Medline, Embase and CENTRAL databases for randomized controlled trials (RCTs) and reviews of GDT in surgical patients. To minimize heterogeneity we excluded studies involving cardiac, trauma, and paediatric surgery. Extremely high risk, high risk and intermediate risks of mortality were defined as >20%, 5 to 20% and <5% mortality rates in the control arms of the trials, respectively. Meta analyses were performed and Forest plots drawn using RevMan software. Data are presented as odd ratios (OR; 95% confidence intervals (CI), and P-values). A total of 32 RCTs including 2,808 patients were reviewed. All studies reported mortality. Five studies (including 300 patients) were excluded from assessment of complication rates as the number of patients with complications was not reported. The mortality benefit of GDT was confined to the extremely high-risk group (OR = 0.20, 95% CI 0.09 to 0.41; P < 0.0001). Complication rates were reduced in all subgroups (OR = 0.45, 95% CI 0.34 to 0.60; P < 0.00001). The morbidity benefit was greatest amongst patients in the extremely high-risk subgroup (OR = 0.27, 95% CI 0.15 to 0.51; P < 0.0001), followed by the intermediate risk subgroup (OR = 0.43, 95% CI 0.27 to 0.67; P = 0.0002), and the high-risk subgroup (OR 0.56, 95% CI 0.36 to 0.89; P = 0.01). Despite heterogeneity in trial quality and design, we found GDT to be beneficial in all high-risk patients undergoing major surgery. The mortality benefit of GDT was confined to the subgroup of patients at extremely high risk of death. The reduction of complication rates was seen across all subgroups of GDT patients.

Trans-Serosal Leakage of Proinflammatory Mediators during Abdominal Aortic Aneurysm Repair: Role of Phospholipase A2 in Activating Leukocytes

Gut barrier failure and the resultant translocation of luminal bacteria and bacterial products into the systemic circulation have been proposed as pathogenic mechanisms of multiorgan dysfunction syndrome (MODS) in open repair of abdominal aortic aneurysm (AAA). Our study aimed to demonstrate the direct release of gut-derived inflammatory mediators via the trans-serosal route in humans. Fifteen patients who underwent elective infrarenal open repair of AAA were randomized into two groups. In Group I patients (n = 10), the small intestine was exteriorized into a bowel bag. In Group II patients (n = 5), the small intestine was packed within the peritoneal cavity using large gauzes. We collected the bowel bag fluid in Group I and the ascites fluid, squeezed out from the gauzes at the end of surgery, in Group II. Leukocytes were collected from patients' blood samples. Incubation with the bowel bag fluid and ascites fluid caused a significant increase in both granulocyte pseudopod formation and CD11b expression compared to that with control fluid (p < 0.01). The addition of phospholipase A2 (PLA2) inhibitor quinacrine abolished leukocyte activation by the bowel bag fluid. Based on these results, we consider that trasns-serosal leakage of gut-derived mediators occurred during the open repair of AAA; further, sPLA2 may be the most potent mediator in the activation of leukocytes among such gut-derived mediators in AAA surgery.

Meta-analysis on the effect of dopexamine on in-hospital mortality

The objective of the study was to determine whether dopexamine alters in-hospital mortality. The following databases were searched, Embase (1974-July 2007), Medline (1950-July 2007), CINAHL, PubMed and Cochrane Clinical Register of Controlled Trials (CENTRAL). Two reviewers independently checked the quality of the studies and extracted data. Six randomised controlled trials totalling 935 patients were included. Mortality was not significantly different with dopexamine treatment (relative risk 0.75, 95% confidence interval 0.48-1.18, p = 0.22). In conclusion, dopexamine does not improve in-hospital mortality in patients undergoing major abdominal surgery and in the critically ill.

Effects of dopexamine on the intestinal microvascular blood flow and leukocyte activation in a sepsis model in rats

INTRODUCTION

The administration of dopexamine may constitute a therapeutical option to improve hepatosplanchnic perfusion in sepsis. In order to verify this hypothesis, we administered dopexamine in an experimental sepsis model in rats.

METHODS

This prospective, randomized, controlled laboratory study was conducted in 42 Wistar rats. The animals were divided into 3 groups. Group 1 (CON group) served as control group. The Animals of groups 2 (LPS Group) and 3 received an endotoxin infusion (20 mg/kgfor 15 min). In addition, in group 3 (DPX group) dopexamine was administered 0.5 microg/kg/minover 4 hours. One half of the animals of each group underwent studies of intestinal microvascular blood flow (IMBF) using laser Doppler fluxmetry. In the other half an intravital microscopic evaluation of the leukocyte endothelium cell interaction in the intestinal microcirculation was performed. Functional capillary denstity (FCD) in the intestinal mucosaand the circular as well as the longitudinal muscle layer was estimated.

RESULTS

One hour after endotoxin challenge IMBF decreased significantly in the untreated LPS group to 51% compared to baseline (p<0.05). In DPX treated endotoxin animals we found significantly higher values at the level of CON group. The after endotoxin challenge impaired FCD was improved by dopexamine in the longitudinal (DPX + 33% vs. LPS; p <0.05) and in the circular muscle layer (DPX + 48% vs. LPS; p < 0.05) as a result of dopexamine administration. The administration of dopexamine reduced the count of firmly adherent leukocytes when compared to the untreated LPS group (-31%, p<0.05). TNF-alpha plasma levels were reduced by dopexamine infusion (LPS group 3637 +/- 553 pg/mL; DPXgroup 1933 +/- 201 pg/mL) one hour after endotoxin challenge.

CONCLUSIONS

The administration of dopexamine improved IMBF and FCD as parameters of intestinal microcirculation and reduced leukocyte activation as a parameter of inflammation in experimental sepsis.

Effects of dopexamine in a rat model of supracoeliac aortic cross-clamping and declamping

This experimental study in rats was designed to demonstrate effects of dopexamine (3 microg kg(-1) min(-1), n = 6) or physiologic saline solution (n = 6) on systemic as well as regional perfusion during 30 min of supracoeliac aortic cross-clamping and during 180 min of reperfusion following declamping. Rats were surgically instrumented with arterial, right atrial and portal venous catheters, ultrasonic flow probes around the abdominal aorta, superior mesenteric and carotid artery, and a paediatric tonometer for intestinal mucosal PCO(2) measurement. During 120 min of reperfusion, fluid resuscitation was titrated to keep abdominal aortic blood flow above 80% of baseline values. We found that during cross-clamping, values of arterial lactate (p = 0.002) and intestinal tonometric PCO(2) (p = 0.018) were higher in the dopexamine group than in the control group.

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 and its role in the protection of hepatosplanchnic and renal perfusion in high-risk surgical and critically ill patients

BACKGROUND

Dopexamine is increasingly being used in high-risk surgical and critically ill patients to preserve hepatosplanchnic and renal perfusion. This systematic review of randomized controlled trials was undertaken to investigate the clinical evidence for using dopexamine in this role.

METHODS

Data sources included Medline, Cochrane Library, EMBASE and CINAHL and reference lists of relevant articles. Randomized controlled trials which compared dopexamine treatment with a control group, in high-risk surgical and critically ill adult patients and with primary outcome measures designed to assess hepatosplanchnic and renal perfusion were included. Articles not published in English were excluded.

RESULTS

Twenty-one trials were selected from the literature search. The results suggest that dopexamine may protect against colonic mucosal damage in patients undergoing abdominal aortic surgery and may improve gastric mucosal pHi in general surgical patients, especially those with preoperative gastric mucosal pHi measurements <7.35 and those undergoing pancreatico-duodenectomy surgery. Dopexamine may have beneficial effects on renal perfusion in patients undergoing cardiac surgery but appears to have little or no benefit on gastric mucosal pHi in the same patient population. In critically ill patients none of the studies demonstrated a beneficial effect of dopexamine on either hepatosplanchnic or renal perfusion.

CONCLUSION

The evidence provided by the existing studies is both inadequate and inconsistent. There is insufficient evidence to offer reliable recommendations on the clinical use of dopexamine for the protection of either hepatosplanchnic or renal perfusion in high-risk surgical patients. Furthermore, there is no current evidence to support a role for dopexamine in protecting either hepatosplanchnic or renal perfusion in critically ill patients.

Local Metabolic Effects of Dopexamine on the Intestine During Mesenteric Hypoperfusion

This self-controlled experimental study was designed to test the hypothesis that dopexamine, a synthetic catecholamine that activates dopaminergic (DA-1) and beta2-adrenergic receptors, improves oxygenation in the jejunal mucosa during intestinal hypotension. In six normoventilated barbiturate-anesthetized pigs, controlled reductions in superior mesenteric arterial pressure (PSMA) was obtained by an adjustable clamp around the artery. Dopexamine infusions (0.5 and 1.0 microg.kg(-1).min(-1)) were administered at a freely variable PSMA (i.e., with the perivascular clamp fully open) and at a PSMA of 50 mmHg and 30 mmHg. We continuously measured superior mesenteric venous blood flow (QMES; transit-time ultrasonic flowmetry), jejunal mucosal perfusion (laser Doppler flowmetry), and tissue oxygen tension (PO2TISSUE; microoximetry). Jejunal luminal microdialysate of lactate, pyruvate, and glucose were measured every 5 min. Measurements of mucosal PCO2 (air tonometry), together with blood sampling and end-tidal PCO2 measurements, enabled calculations of pHi and PCO2 gap. Dopexamine reduced mesenteric vascular resistance and increased QMES at a PSMA of 50 mmHg and 30 mmHg. At a PSMA of 30 mmHg, dopexamine increased mesenteric oxygen delivery but did not influence mesenteric oxygen uptake or extraction. In this situation, dopexamine had no beneficial effect on jejunal mucosal blood flow. On the contrary, dopexamine increased mesenteric net lactate production and PCO2 gap, whereas PO2TISSUE and pHi decreased. Jejunal luminal microdialysate data demonstrated an increased lactate concentration and a pattern of decreased glucose concentration and increased luminal lactate-pyruvate ratio. These negative metabolic effects of dopexamine should be taken into account in situations of low perfusion pressures.