Delayed diagnosis of vascular injuries during lumbar discectomy

We report an accidental perforation of the left iliac artery and vein during lumbar discectomy in the kneeling position. During the surgical procedure, a brief and transient hypotension occurred, although the surgeon did not observe any abnormal bleeding in the operating field. In the recovery room, arterial blood pressure decreased, and tachycardia, pallor, and abdominal pain occurred. Retroperitoneal bleeding was suspected. Immediate fluid resuscitation was initiated, anesthesia was continued, and red blood cells were ordered. The use of medical antishock trousers enabled temporization until vascular surgeons were ready. An emergent laparotomy was performed to repair vascular injuries. The delayed symptoms, use of medical antishock trousers, and implications for anesthetists are discussed.

Electrophysiological effects of dofetilide in an in vitro model of "border zone" between normal and ischemic/reperfused myocardium

BACKGROUND

To evaluate both class III activity and antiarrhythmic action of dofetilide at the level of the "border zone," we investigated its electrophysiological effects on guinea pig ventricular strips submitted partly to normoxia (normal zone, NZ) and partly to simulated severe ischemia, then reperfusion (altered zone, AZ).

METHODS AND RESULTS

Because of the differential class III effects of dofetilide in normal and ischemic regions, the dispersion of the action potential duration at 90% repolarization (APD(90)) between NZ and AZ was reduced by 5 nmol/L of drug during early ischemia (at 10 minutes, APD(90) NZ/APD(90) AZ was 1.68+/-0.22 versus 2.82+/-0.17 in control, P<0.05), whereas 50 nmol/L dofetilide worsened it during late ischemia (at 30 minutes, APD(90) NZ/APD(90) AZ was 4.62+/-0.76 versus 2.57+/-0.21 in control, P<0.05). Concomitantly, dofetilide at 5, 10, and 50 nmol/L abolished the early extrastimulus (ES)-induced arrhythmias, and at 10 and 50 nmol/L, it significantly enhanced the incidence of late spontaneous repetitive responses (in 86% and 75% of preparations treated with 10 and 50 nmol/L, respectively, versus 25% in control, P<0.05). During reperfusion, dofetilide at 5, 10, and 50 nmol/L exhibited concentration-dependent class III effects, as it did in the NZ, and did not modify the incidence of spontaneous arrhythmias.

CONCLUSIONS

Dofetilide 5 nmol/L decreased APD(90) dispersion between NZ and AZ and reduced the early ES-induced arrhythmias. However, dofetilide 50 nmol/L increased APD(90) dispersion, and at 10 and 50 nmol/L, it increased the late spontaneous arrhythmias.

[Mesenteric vein and inferior vena cava thrombosis: disseminated intravascular coagulation and/or G 20210 A mutation of the prothrombin gene?]

The authors report the case of a 30-year-old man who died from pulmonary embolism and multiorgan failure caused by mesenteric and inferior vena cava thrombosis. The patient was found heterozygous for the prothrombin gene variant (G 20210 A). The family study showed the same asymptomatic anomaly in his brother. This recently described mutation is associated with an increased risk for venous thrombosis. The investigations and treatment of mesenteric venous thrombosis are discussed.

In vitro effects of desflurane, sevoflurane, isoflurane, and halothane in isolated human right atria

BACKGROUND

Direct myocardial effects of volatile anesthetics have been studied in various animal species in vitro. This study evaluated the effects of equianesthetic concentrations of desflurane, sevoflurane, isoflurane, and halothane on contractile parameters of isolated human atria in vitro.

METHODS

Human right atrial trabeculae, obtained from patients undergoing coronary bypass surgery, were studied in an oxygenated (95% O2-5% CO2) Tyrode's modified solution ([Ca2+]o = 2.0 mM, 30 degrees C, stimulation frequency 0.5 Hz). The effects of equianesthetic concentrations (0.5, 1, 1.5, 2, and 2.5 minimum alveolar concentration [MAC]) of desflurane, sevoflurane, isoflurane, and halothane on inotropic and lusitropic parameters of isometric twitches were measured.

RESULTS

Isoflurane, sevoflurane, and desflurane induced a moderate concentration-dependent decrease in active isometric force, which was significantly lower than that induced by halothane. In the presence of adrenoceptor blockade, the desflurane-induced decrease in peak of the positive force derivative and time to peak force became comparable to those induced by isoflurane. Halothane induced a concentration-dependent decrease in time to half-relaxation and a contraction-relaxation coupling parameter significantly greater than those induced by isoflurane, sevoflurane and desflurane.

CONCLUSIONS

In isolated human atrial myocardium, desflurane, sevoflurane, and isoflurane induced a moderate concentration-dependent negative inotropic effect. The effect of desflurane on time to peak force and peak of the positive force derivative could be related to intramyocardial catecholamine release. At clinically relevant concentrations, desflurane, sevoflurane, and isoflurane did not modify isometric relaxation.

KATP channels and 'border zone' arrhythmias: role of the repolarization dispersion between normal and ischaemic ventricular regions

1. In order to investigate the role of KATP channel activation and repolarization dispersion on the 'border zone' arrhythmias induced by ischaemia-reperfusion, the effects of glibenclamide and bimakalim, agents modifying action potential (AP) duration, were studied in an in vitro model of myocardial 'border zone'. 2. The electrophysiological effects of 10 microM glibenclamide and 1 microM bimakalim (n=8 each), respectively KATP channel blocker and activator, were investigated on guinea-pig ventricular strips submitted partly to normal conditions (normal zone, NZ) and partly to simulated ischaemic then reperfused conditions (altered zone, AZ). 3. By preventing the ischaemia-induced AP shortening (P<0.0001), glibenclamide reduced the dispersion of AP duration 90% (APD90) between NZ and AZ (P<0.0001), and concomitantly inhibited the 'border zone' arrhythmias induced by an extrastimulus (ES), their absence being significantly related to the lessened APD90 dispersion (chi2=8.28, P<0.01). 4. Bimakalim, which also reduced the APD90 dispersion (P<0.005) due to differential AP shortening in normal and ischaemic tissues, decreased the incidence of myocardial conduction blocks (25% of preparations versus 83% in control, n=12, P<0.05) and favoured 'border zone' spontaneous arrhythmias (75% of preparations versus 25% in control, P<0.05). 5. During reperfusion, unlike bimakalim, glibenclamide inhibited the ES-induced arrhythmias and reduced the incidence of the spontaneous ones (12% of preparations versus 92% in control, P<0.05), this latter effect being significantly related (chi2=6.13, P<0.02) to the lessened ischaemia-induced AP shortening in the presence of glibenclamide (P<0.0001). 6. These results suggest that KATP blockade may protect the ischaemic-reperfused myocardium from 'border zone' arrhythmias concomitantly with a reduction of APD90 dispersion between normal and ischaemic regions. Conversely, KATP channel activation may modify the incidence of conduction blocks and exacerbate the ischaemia-induced 'border zone' arrhythmias.

[Echo-doppler surveillance of revascularization of the legs in asymptomatic postoperative patients. Why? With what rhythm? How much time? How?]

AIM

Routine duplex surveillance of patients following an arterial operation includes the scanning of symptomless patients. While the benefits of preventive correction of deteriorations, stenoses or dilatations, following aortic or lower limb arterial reconstruction are undisputed, there is no hard data on the effectiveness of this surveillance in terms of limb salvage, on its cost, and on the optimal frequency and duration.

METHODS

The AA review the literature on this subject and suggest a programme which reconciles the patients' interests with the best use of health care financial resources.

RESULTS

The possible complications depend on the type of operation. Some are symptomless. They occur mainly during the first year and less frequently, but regularly so, during the subsequent years. There is therefore no time limit for the duration of the surveillance. The effectiveness of this surveillance is low and thus the examination must be meticulous and its frequency adapted to the risks. Broadly speaking: During the first year, aorto-ilio-femoral reconstructions must be screened at one month, six months and one year; by-passes below the groin with no particular risk at six months and one year; by-passes at risk and those anastomosed to a lower leg or ankle artery require a further check-up at one month and three months. After the first year, aorto-ilio-femoral and similar by-passes must be checked annually; by-passes below the groin, when at risk, must be checked annually; in those without any particular risk, a check-up every two years seems to be sufficient. Any patient found to have a deterioration on screening must be checked every six months.

CONCLUSION

Careful screening is the only way of discovering a symptomless deterioration before the development of serious complications. As every arteriole reconstruction should be followed by a lifelong surveillance, in times of financial constraints the frequency of the check-ups must be tailored according to the risks present and the quality of the surveillance must be faultless.

[Traumatic rupture of the pericardium. A rare diagnosis]

Rupture of the pericardium is a rare complication of blunt chest trauma. The diagnosis is difficult and if it remains unrecognized, severe complications such as heart herniation may occur. We report the case of a 19-year-old patient with a traumatic rupture of the pericardium. The diagnosis was suggested by a pneumopericardium seen on the chest radiograph and CT-scan. Emergency thoracotomy enabled localisation of the tear, assessment of its size, and reparation of the tear to prevent heart herniation.

KATP channel modulators and myocardial damages induced by ischemia-reperfusion: membrane lipids injury and arrhythmias

Although KATP channels have been proposed as playing a role in most types of myocardial damage associated with ischemia/reperfusion, the potential benefits of KATP channel modulators against the biochemical and electrical disturbances observed during ischemia remain unclear. We have thus studied the effects of glibenclamide and cromakalim, KATP channel blocker and opener respectively, on membrane lipid injury and arrhythmias, in a model of ischemic-reperfused guinea-pig myocardium. Ventricular strips were prelabeled with [3H] arachidonic acid, then subjected to normal conditions (Time-related Control) or to simulated ischemic-reperfused conditions in absence of drug (Control) or in presence of glibenclamide 10 microM or cromakalim 10 microM. The release of radioactive compounds was counted by liquid scintillation spectrometry, while action potentials (AP) were recorded with intracellular microelectrodes. Reperfusion induced a significant increase of arachidonic acid release (P < 0.05 versus Time-related Control). Glibenclamide inhibited the reperfusion-induced arachidonic acid release while cromakalim only delayed it (respectively 483 +/- 87 dpm/g, P < 0.05 and 790 +/- 143 dpm/g. NS versus 838 +/- 80 dpm/g for Control, after 30 min of reperfusion). Unlike glibenclamide, cromakalim was proarrhythmic during reperfusion (in 100% of preparations versus 33% in Control or in presence of glibenclamide, P < 0.05). This in vitro study shows that glibenclamide prevented the reperfusion-induced membrane arachidonic acid release, without proarrhythmic effect, whereas cromakalim, associated with proarrhythmicity, was unable to protect myocardium from cell lipid damage.

Proarrhythmic and antiarrhythmic effects of bupivacaine in an in vitro model of myocardial ischemia and reperfusion

BACKGROUND

Bupivacaine may have toxic cardiovascular effects when accidentally administered by intravascular injection. However, its electrophysiologic effects in the presence of myocardial ischemia remain unknown. The authors evaluated the electrophysiologic and anti- and proarrhythmic effects of bupivacaine in an in vitro model of the ischemic and reperfused myocardium.

METHODS

In a double-chamber bath, a guinea pig right ventricular muscle strip was subjected partly to normal conditions and partly to simulated ischemia followed by reperfusion. The electrophysiologic effects of bupivacaine were studied at 1, 5, and 10 microM concentrations.

RESULTS

Bupivacaine (5 and 10 microM) decreased the maximal upstroke velocity of the action potential (Vmax) in normoxic conditions and further decreased (10 microM) the Vmax decrease induced by ischemic conditions. Bupivacaine reduced the mean occurrence time to the onset of myocardial conduction blocks (9 +/- 3 min; mean +/- SD; P < 0.005 with 5 and 10 microM, compared with 17 +/- 6 min during simulated ischemia with no drug or control), and it increased the number of preparations that became inexcitable to pacing (55% of preparations, with 1 microM and 100% with 5 and 10 microM, compared with 17% for the control group). The incidence of spontaneous arrhythmias was reduced by 5 and 10 microM bupivacaine during ischemia and reperfusion and was enhanced by 1 microM bupivacaine during the ischemic phase.

CONCLUSIONS

In guinea pig myocardium under ischemic conditions, bupivacaine induced a loss of excitability at concentrations of 5 and 10 microM. Proarrhythmic effects observed at 1 microM were considered as lower than the cardiotoxic range in normoxic conditions. The incidence of reperfusion arrhythmias was decreased at all concentrations.

Proarrhythmic effects of DL- and D-sotalol on the "border zone" between normal and ischemic regions of isolated ventricular myocardium and antiarrhythmic effects on reperfusion

Considering the Survival With ORal D-sotalol (SWORD) study results, in which mortality was higher in patients treated by the pure class III agent D-sotalol, we tested DL- and D-sotalol (5 and 10 microM) in an in vitro model of "border zone" arrhythmias. Isolated guinea-pig ventricular strips were partly exposed to normoxia ("Normal Zone," NZ) and partly to modified Tyrode's solution ("Ischemic Zone," IZ) for 15 or 30 min ("ischemia"), followed by return to normoxia for 30 min ("reperfusion"). Resting membrane potential, action potential (AP) amplitude, and maximal upstroke velocity of AP were not significantly modified. DL- And D-sotalol, 5 and 10 microM, lengthened AP duration 90% (APD90) in NZ (p < 0.05), whereas these drugs were unable to prevent ischemia-induced APD shortening. By using the accelerated failure time Weibull's model, and a large number of reference experiments to control random variability of analyzed covariates, DL- and D-sotalol increased significantly the incidence of spontaneous arrhythmias during ischemia (chi2 = 24.79; p = 0.0367): 83 (5 microM D- and DL-sotalol), 86, and 62% (10 microM D- and DL-sotalol, respectively) versus 32% of controls. During reperfusion, 10 microM DL-sotalol prevented the occurrence of spontaneous arrhythmias (chi2 = 46.74; p = 0.0001) similar to what seen with the beta-blocking agent propranolol (10 microM). These data, providing evidence for proarrhythmic effects of DL- and D-sotalol on border-zone arrhythmias, concomitant with differential class III actions on NZ versus IZ, might be considered for understanding the SWORD study results.

Pulsed transthrombotic fibrinolysis: technique and results in the management of occluded lower limb bypass grafts

Between March 1987 and March 1993 we used pulsed transthrombotic fibrinolysis to treat 58 symptomatic thrombotic occlusions of lower limb bypass grafts in 45 patients. There were 17 suprainguinal grafts and 28 infrainguinal grafts. Treatment consisted of pulsed infusion of fibrinolytic agents into the thrombus followed by continuous infusion using an electric pump. Minor percutaneous or surgical procedures were often associated. The mean delay to treatment was 7 days. The mean duration of treatment was 150 +/- 66 minutes. Immediate patency was achieved in 88% of cases with no significant difference between suprainguinal and infrainguinal grafts. The clinical success rate was 55%. Actuarial patency at 1 year was 54% +/- 11% for suprainguinal grafts and 26% +/- 7% for infrainguinal grafts. The probability of patency was much lower in patients whose grafts had been implanted within 3 months before occlusion and in patients in whom an adjuvant procedure had not been performed. This study demonstrates that, in cases not requiring immediate surgery, pulsed transthrombotic fibrinolysis can achieve durable patency by treating both the bypass and distal arterial network. This technique allows identification of lesions causing thrombosis and adaptation of treatment specifically to these lesions.

[Associated carotid and coronary lesions: carotid endoluminal angioplasty before coronary surgery]

OBJECTIVE

There is debate over the therapeutic strategy in patients with lesions of both the coronary arteries and the carotid arteries. Improvement in angioplasty techniques for the carotid artery would be a minimally invasive alternative.

METHODS

Between January 1993 and June 1995, 12 patients who underwent endoluminal angioplasty of the carotid artery before coronary bypass surgery (mean 17.9 days before) were included in the study. Mean age was 70 +/- 3.2 years. The carotid lesions were asymptomatic in all patients who had stable angina.

RESULTS

The mean number of bypasses was 2.9 per patient. Five patients had a contralateral stenosis of the internal carotid artery. Angioplasty was performed under cerebral protection using a three way coaxial catheter. A Strecker stent was required in 8 cases. One patient presented transient hemianopsia. All patients were seen again at 4 months for an angiogram then at 6 months for a Doppler examination. One patient needed complete redilatation with a stent and one other required dilatation of the stent.

CONCLUSIONS

Endoluminal angioplasty of the carotid arteries gave encouraging results in this high-risk population (underlying disease, age, bilateral carotid lesions, arterial coronary grafts). This technique should be used more widely for patients with severe multiple arterial lesions.

[Cardiac transplantation. Evaluation of a consecutive series of 75 grafts]

OBJECTIVES

The global results of various series of heart transplantation (HT) are essential to assess the life expectancy provided by this technique. Due to the increasing graft shortage, it appears essential to very strictly candidates for HT.

METHODS

From March 8, 1989 to December 7, 1994, 75 orthotopic Hts were performed in 62 men and 12 women (1 case of retransplantation). The mean age was 47.46 +/- 15.02 years (range: 2.5-66 years). Four patients were younger than 10 years and 22 were older than 60 years. Our series included more cases of ischaemic heart disease (36) than dilated cardiomyopathies (33), with a history of cardiac surgery in almost one quarter (20) of patients with ischaemic heart disease.

RESULTS

The immediate postoperative survival rate was 94.7% with 3 deaths attributable to refractory pulmonary hypertension associated with graft failure and one death related to postoperative tamponade. Five other patients died during the following 3 months, increasing the mean global survival to 88%. After a mean follow-up of 2.1 years (maximum 5.8 years), the actuarial 5-year survival rate was 56.8%. Eleven patients died between 4 and 38 months (mean: 18.2 months). Two deaths were due to cancers, 4 were due to septicaemia, another 4 were due to rejection and finally 1 was due to meningeal haemorrhage. The frequency (19) of reoperations for clot removal was due to the large number of patients with a history of previous heart surgery (20).

CONCLUSION

Strict recipient selection, possibly based on 123I-MIBG scintigraphy, the use of pulsatile circulatory assistance systems, improved CMV, morphometry and donor-recipient age matching, should optimize the results of a technique, whose efficacy is confirmed in this series.

[Indications and role of albumin for vascular loading in the operating room]

Prospective clinical studies on albumin and non human colloids, administered peroperatively, were analysed. Only those with a level of evidence I or II were considered. On the basis of the cost-effectiveness ratio, albumin should not be the first choice treatment for peroperative plasma volume expansion. Low molecular weight hydroxyethylstarch is as efficient for restoration and maintenance of volaemia and colloid osmotic pressure. Albumin is administered when other colloids are contra-indicated or when their upper limit of volume has been reached.

Radioimmunoassay for plasma histamine: a study of false positive and false negative values

In order to achieve a correct diagnosis of drug anaphylaxis using a radioimmunoassay devoid of interferences, we have studied factors leading to false positive or false negative values of plasma histamine. Different steps in sample collection were studied systematically in 30 normal volunteers. False positive values were found in haemolysed samples, with histamine concentrations being correlated with haemoglobin concentrations, and where plasma was aspirated from the white-cell layer. There was no significant increase when a tourniquet or vacuum tubes were used, or when blood tubes were left at 4 degrees C overnight. In 12 patients who experienced an anaphylactic reaction, histamine disappeared from blood 10 times more slowly than expected. False negative values were found in two pregnant women and one heparinized patient. Histamine was remarkably stable in vitro in blood or plasma samples, whereas it disappeared rapidly when plasma from a pregnant woman or a heparinized patient was added to the sample. We conclude that false positive and false negative values are rare when using this radioimmunoassay.

EARLY DIAGNOSIS OF ANAPHYLACTIC REACTIONS TO NEUROMUSCULAR BLOCKING DRUGS

Neuromuscular blocking drugs (NMB) are involved in most of the anaphylactic reactions occurring during anaesthesia. Patients are evaluated usually 6 weeks after the reaction, by skin testing. In order to obtain an earlier diagnosis, we have measured plasma concentrations of histamine, tryptase and NMB-specific IgE antibodies in 14 patients after an anaphylactoid reaction. We have compared the results with those of skin tests and specific IgE obtained 8 weeks later. Good agreement was observed in all subjects between the results of skin tests and the values for histamine and tryptase, provided that both markers were measured simultaneously. Furthermore, there was no significant difference between the concentrations of NMB-specific IgE antibodies observed at the time of the reaction and 8 weeks later. Thus anaphylaxis to neuromuscular blocking drugs can be demonstrated at the time of the reaction by measuring plasma concentrations of histamine, tryptase and specific IgE. In the event of the patient's death, such measurements may be useful in identifying the likely cause.

[Early biological markers of anaphylactoid reactions occurring during anesthesia]

Three markers of in vivo histamine release, i.e. plasma histamine and tryptase, and urinary methylhistamine, were assessed using sensitive radioimmunoassays in 18 patients who had experienced an adverse reaction to an anaesthetic agent. Controls were obtained from 35 patients following a general anaesthetic, which included a muscle relaxant, and who remained free from any adverse reaction. A first blood sample was obtained from all 18 patients a mean 25 +/- 26 min after the reaction, and a second one in thirteen a mean 120 +/- 65 min after the reaction. Ten patients had had a life-threatening reaction. Plasma histamine levels were increased in all these cases, and tryptase concentrations in 9 out of 10. Urinary methylhistamine rarely reached pathological levels (4 out of 10). Skin tests were positive in the four tested patients. Plasma histamine concentration was still high in 8 cases thirty minutes after the reaction, and remained increased for more than 2 h in two patients. Among the other eight patients with a moderate reaction, 3 had high histamine levels, with normal or weakly increased tryptase concentrations, and normal urinary methylhistamine. Two of these patients had positive skin tests. There were no abnormal findings in any of the investigations carried out in the other five patients, except for a slightly positive skin test to atracurium in one patient. Plasma histamine had a higher sensitivity than tryptase levels. Methylhistamine concentrations were only rarely of interest. There were no false positives with the three investigated markers.(ABSTRACT TRUNCATED AT 250 WORDS)

[Efficacy and tolerance of Elohes 6% during peroperative normovolemic dilution]

This study assessed the cardiovascular stability of intraoperative normovolaemic haemodilution carried out with 6% Elohes during the exchange, the intraoperative, recovery and postoperative periods, as well as its effects on coagulation and renal function. Ten patients, ranked ASA 1, were included. Patients were premedicated with 100 mg of hydroxyzine, and anaesthesia was induced with 2 mg.kg-1 propofol, 3 micrograms.kg-1 fentanyl, and 0.5 mg.kg-1 atracurium. Maintenance was obtained with propofol, fentanyl and 50% nitrous oxide in oxygen. Haemodilution, carried out with a peripheral venous catheter, size 14 G, consisted in the removal of 15 ml.kg-1 of blood and its simultaneous replacement with Elohes 6%. Heart rate, systolic, diastolic and mean blood pressures were recorded before anaesthetic induction, every 5 min during the haemodilution, and thereafter during surgery, recovery and postoperative periods, up to the third postoperative day. Blood haemoglobin, fibrinogen, prothrombin, sodium, potassium, urea and creatinine concentrations, haematocrit, platelet count, and bleeding and activated cephalin times were assessed before and immediately after haemodilution, and on postoperative days 1 and 3. A mean of 1,295 +/- 68 ml of blood were removed during a 32 +/- 2 min period, and replaced by 1,315 +/- 64 ml of Elohes. Haematocrit decreased from 44 +/- 1.1% to 29.7 +/- 0.8%. There were no significant alterations in other parameters, except for an increase in heart rate at the time of extubation. Cardiovascular parameters, as well as the haemodilution, were stable up to the end of the study period. It is concluded that replacing blood with Elohes for intentional haemodilution affords convenient cardiovascular stability.(ABSTRACT TRUNCATED AT 250 WORDS)

Compared peripheral vascular responses to intravenous and intra-arterial administrations of positive inotropic agents in conscious dogs

In addition to their direct effects on cardiac contractility, a number of positive inotropic agents also induce, through direct peripheral vasodilation, a reduction in afterload which is of major importance in their beneficial effects in the treatment of congestive heart failure. However, the induced increase in cardiac output can indirectly improve perfusion of peripheral vessels through a flow-mediated mechanism. Thus, the goal of the present study was to compare the direct peripheral vasomotor effects assessed in the iliac vascular bed of four positive inotropic agents: DPI 201-106, ouabain, milrinone and dobutamine, in the presence and absence of simultaneous changes in cardiac function. These drugs were administered either through intravenous or intra-arterial (aorto-iliac catheter) routes in 6 conscious dogs, chronically instrumented for the measurement of heart rate, arterial pressure, left ventricular dP/dt, iliac artery blood flow and iliac artery diameter (sonomicrometry). Intravenous doses were selected as those inducing equipotent positive inotropic responses whereas intra-arterial doses were below those required to induce any significant change in systemic hemodynamics. Ouabain decreased and milrinone increased both iliac blood flow and diameter after either intravenous or intra-arterial administrations. In contrast, iliac blood flow did not change after intra-arterial administration of DPI 201-106 and dobutamine whereas iliac diameter was not modified by DPI 201-106 and even decreased with dobutamine. After intravenous administration, DPI 201-106 but not dobutamine, increased both iliac blood flow and diameter. Thus, this experimental preparation can differentiate inotropic agents with direct vasodilating (milrinone) or constricting (ouabain) properties and those (DPI 201-106 and dobutamine) with indirect vasodilating effects most likely mediated by the improvement in cardiac function.