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PubMedDate not supplied

Metrizamide, the ideal radiopaque filling material for detachable silicone balloon embolization.

Porcine visceral and extremity arteries were embolized with detachable silastic balloons; 10 balloons were filled with isoosmolar metrizamide, five were filled with 30% meglumine-sodium diatrizoate and five were filled with 3:1 mixtures of blood and 76% meglumine-sodium diatrizoate. Follow-up radiographs were obtained weekly for 2 weeks, at 4 weeks and at 5 months. At 3 months, arteriography was performed. All balloons occluded the vessel completely upon detachment. Balloons filled with metrizamide did not change their volume or radiopacity during the entire observation period and all remained inflated. The balloons filled with diatrizoate salts enlarged by osmotic growth during the first two weeks and there was a decrease in opacity. Thereafter, one balloon filled with 30% diatrizoate salt solution and one filled with blood-76% diatrizoate deflated. In the former, the embolized artery remained occluded, while in the latter, the vessel reopened and the balloon was found incorporated into the vessel wall at the site of detachment. It is concluded that isoosmolar metrizamide is an ideal filler for detachable silastic balloons since it does not lead to changes in volume or radiopacity and also guarantees long-term vascular occlusion.

Angiography↗
PubMed2002

Ionic radiocontrast media disrupt intercellular contacts via an extracellular calcium-independent mechanism.

Direct cytotoxic effects of radiocontrast (RC) agents have been implicated in radiocontrast nephropathy (RCIN). The interaction between extracellular calcium, which plays a central role in intercellular contacts, and the in vitro toxicity of RC was tested in Madin-Darby canine kidney (MDCK) cell monolayers grown on permeable supports. Cell viability was determined by trypan blue exclusion. The function of intercellular junctions was assessed by measuring the electrical transmonolayer resistance (TMR). The cell contacts were examined with indirect immunofluorescence microscopy using antibodies against the junctional proteins E-cadherin, ZO-1 and occludin. The ionic RC agents diatrizoate and ioxaglate (74 mg iodine/ml), but not the nonionic compounds iohexol or iodixanol, decreased ionized calcium (Ca2+) in the incubation media from 1.48 +/- 0.04 mM (control) to 0.89 +/- 0.06 mM (diatrizoate), respectively to 1.05 +/- 0.08 mM (ioxaglate). Diatrizoate, and to a lesser extent ioxaglate, reduced the number of viable MDCK cells and showed a redistribution of the E-cadherin, ZO-1 and occludin immunofluorescence signal with a parallel decrease of the TMR indicating an impaired monolayer integrity. A similar reduction of extracellular Ca2+ through EGTA failed to reproduce these effects. Conversely, raising Ca2+ in diatrizoate-containing media to control levels did not abrogate its toxicity. In conclusion, the ionic RC agents diatrizoate and ioxaglate, but not the nonionic compounds iohexol or iodixanol, reduce extracellular Ca2+ in vitro. However, this reduction of Ca2+ does not explain their cytotoxic effects which could contribute to the pathogenesis of RCIN in vivo by opening intercellular junctions.

Animals↗
PubMed1991

Renal vasoconstriction after low and high osmolar contrast agents in ischemic and non ischemic canine kidney.

We have assessed the effect of contrast media on renal blood flow before and after inducing renal ischemia. Diatrizoate, iopamidol and ioxaglate were injected within 15 seconds at 20 min intervals, at the dose of 1 ml/kg during a control period and 15 min after applying an aortic clamp to reduce the renal perfusion pressure to 70 mmHg. During the control period iopamidol, ioxaglate (17 +/- 13%) and diatrizoate (16 +/- 2%) induced a comparable decrease in renal blood flow (RBF). During the ischemic period the effects of diatrizoate on renal hemodynamic were dramatically enhanced. Ioxaglate andiopamidol induced a 20 +/- 12 and a 32 +/- 9% decrease in RBF at 1 minute, respectively. Iopamidol induced an increase in renal vascular resistance (RVR) from 0.8 +/- 0.08 to 1.46 +/- 0.26 mmHg min/ml (p less than 0.05). Ioxaglate induced an increase in RVR from 0.8 +/- 0.09 to 1.36 +/- 0.38 (p less than 0.05). Diatrizoate induced a 77 +/- 10% decrease in RBF and a maximum increase in RVR at 1 minute from 0.9 +/- 0.09 to 26 +/- 12 mmHg min/ml. There was still a 36 +/- 14% and a 23 +/- 13% decrease in RBF 10 and 20 min after diatrizoate administration. These changes were significantly higher than those observed with all contrast media during the control period and low osmolar contrast media during the ischemic period. We have thus shown that ischemia potentiates the renal vascular effect of contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1989

Hemorrheologic effects of iotrolan after intra-arterial injection in rabbits: comparison with other types of contrast media.

Aqueous solutions of the x-ray contrast media (CM) iotrolan and meglumine diatrizoate with and without gelatin added were injected into the rabbit aorta just above the bifuraction in a dose of 0.3 g I/kg and the duration of opacification of the vessel was measured. The difference between the periods recorded for iotrolan and the viscous diatrizoate solution (4 to 6 seconds) and those for the pure diatrizoate solution (3 to 4 seconds) was statistically significant (p less than or equal to 0.05). The differences are directly correlated to the viscosity of the CM solutions. At first the intra-aortal injection of iotrolan causes a somewhat more marked decline in femoral artery blood flow than diatrizoate. The increase in blood flow, which begins 10 seconds after injection is, however, significantly (p less than or equal to 0.05) less after iotrolan than after diatrizoate. This is attributable to the differences in the osmolalities of the two CM. Due to the fact that it is isotonic to blood and because of its viscosity, iotrolan has certain advantages over conventional agents for arteriography that are relevant to clinical practice.

Angiography↗
PubMedDate not supplied

Contrast media induced ventricular fibrillation during coronary angiography in dogs.

This study is designed to determine which is more critical for contrast media induced ventricular fibrillation (VF), hyperosmolality or lack of sodium ions. The right coronary artery in the canine model was infused continuously with contrast media (CM) for 25 seconds or until ventricular fibrillation occurred. The test solutions included isotonic saline, 305 mg I/ml of meglumine diatrizoate, 370 mg I/ml of meglumine/Na diatrizoate and 370 mg I/ml of metrizamide. The incidence of VF with meglumine/Na diatrizoate was significantly higher than with metrizamide (p less than 0.05). These observations suggest that the hyperosmolality is more critical than the lack of sodium ions in CM when metrizamide is compared with conventional ionic CM. On the other hand, the results showing that contact time until VF was shorter with meglumine diatrizoate than with meglumine/Na diatrizoate may reflect the importance of sodium ions in CM with similar osmolality.

Animals↗
PubMedDate not supplied

Calcium binding by radiopaque media.

This study quantified the binding of ionic calcium by contrast media with disodium edetate and trisodium citrate versus those with only calcium disodium edetate. First, calcium binding by sodium diatrizoate with calcium disodium edetate was measured using an ion-selective electrode at ionic strengths of .08, .16, and .80 molal. Significant binding of calcium was observed, and the probable reaction product is calcium chloride diatrizoate. Second, solutions were mixed containing Renografin 76 (or Hypaque 76) and NaCl at a physiologic ionic strength. The Renografin, which contains disodium edetate and trisodium citrate, caused significantly more binding than did the Hypaque. However, 60% of the drop in ionic calcium was observed with Hypaque and is related to the diatrizoate anion. The nonionic agent iopamidol produced no decrease in ionic calcium. Significant reductions in ionic calcium are produced by both the diatrizoate anion and by edetate and citrate additives.

Calcium↗
PubMed1986

Incidence of fibrillation with dilute contrast media for intra-arterial coronary digital subtraction angiography.

State-of-the-art imaging technology such as digital subtraction angiography can produce coronary artery opacification with contrast media formulations that contain less than 170 mgI/ml. We examined the effect of electrolyte composition in such formulations on the incidence of fibrillation. Right coronary injections of contrast were made for 25 seconds in anesthetized dogs. This injection is longer than clinical injections, but the model approximates the worst condition of a wedged catheter preventing media washout. Formulations of several mixtures of meglumine and sodium diatrizoate (173 to 141 mgI/ml) and sodium diatrizoate alone (143 mgI/ml) produced fibrillation in only 10 to 20% of the injections. Meglumine diatrizoate (141 mgI/ml) and full strength meglumine/sodium diatrizoate (Angiovist 370) produced fibrillation in 100% and 50% of the injections, respectively. These animal studies demonstrate that dilute contrast media containing few or no sodium ions are more likely to induce fibrillation than Angiovist 370, whereas dilute contrast media containing sodium are the least likely to induce fibrillation.

Angiography↗
PubMedDate not supplied

In vitro effects of iodinated contrast media on the growth of staphylococci.

Seven commonly used arthrographic contrast media were examined in vitro for bactericidal effects against Staphylococcus aureus under various conditions simulating clinical settings, using a wide range of bacterial populations (10(1) to 10(8) colony-forming units per ml). The media tested were: sodium diatrizoate and megulumine diatrizoate (E.R. Squibb and Sons, Renogragin-60 and Renografin-76), megulumine diatrizoate (E. R. Squibb and Sons, Renografin-M-60), sodium iothalamate and megulumine iothalamate (Mallinckrodt Chemical Works, Vascoray), sodium iothalamate (Mallinckrodt Chemical Works, Conray 400), meglumine iothalamate (Mallinckrodt Chemical Works, Conray 60), and sodium diatrizoate (Winthrop Laboratories, Hypaque sodium 50%). Effects secondary to the contrast medium used, dilution ratios of the specimens, and time elapsed between the collection and cultivation of the specimens were examined. The contrast material used was found to affect bacterial growth: the Renografin materials showed a bactericidal or bacteriostatic effect, while Vascoray, the Conray materials, and Hypaque sodium 50% failed to inhibit bacterial growth. Bacterial inoculum size exhibited a direct bearing on the bactericidal or bacteriostatic effects of the Renografin but had no effect with the other media. The results indicate that Vascoray, Conray and Hypaque sodium 50% are superior to the Renografin materials for use in arthrography and other procedures in which the aspirate is submitted for microbial culture, because they interfere less with the recovery of these microorganisms.

Contrast Media↗
PubMed1995

Urine profiles and kidney histology after ionic and nonionic radiologic and magnetic resonance contrast media in rats with cisplatin nephropathy.

RATIONALE AND OBJECTIVES: The nephrotoxic drug cisplatin has been used successfully in treating some cancers. Patients with suspected carcinoma frequently undergo examinations with contrast media. We examined whether ionic and nonionic radiologic and magnetic resonance contrast media would have any effect on cisplatin nephropathy in rats. METHODS: Urine and serum profiles were monitored for 24 days after intravenous (i.v.) injections of saline, diatrizoate, iohexol, gadopentetate dimeglumine, and gadodiamide in high doses (4.59 mmol/kg body weight) in rats that received a weekly intraperitoneal (i.p.) injection of cisplatin (1 mg/kg) for 10 weeks. There were 10 rats in each group. Another 10 rats injected with both i.p. and i.v. saline served as control subjects. After euthanization, rats' kidneys were removed for examination by light microscopy and electron microscopy. RESULTS: Light and electron microscopy showed severe morphologic changes, including tubular dilatation, atrophy, and necrosis induced by cisplatin; however, the contrast media did not induce any additional morphologic changes. Gadopentetate dimeglumine, diatrizoate, and iohexol significantly increased (3-20 times) albuminuria compared with i.v. saline in cisplatin nephropathy, whereas gadodiamide did not. Albuminuria was highest after diatrizoate injection. All four contrast media caused an immediate and transient significant increase in the excretion of the brush border enzymes alkaline phosphatase and gamma-glutamyltransferase (125-500 times) and the cytoplasmatic enzymes alanine aminopeptidase and lactate dehydrogenase (16-100 times). Compared with saline, the ionic agents significantly increased the excretion of both glucose (two times) and sodium (three to five times), whereas the nonionic agents did not. CONCLUSION: High doses of radiologic and magnetic resonance contrast agents cause temporary dysfunction in rats with cisplatin nephropathy. Gadodiamide caused the least dysfunction and diatrizoate the most.

Animals↗
PubMed2001

An analysis of mechanisms underlying the antifibrinolytic properties of radiographic contrast agents.

BACKGROUND: Radiographic contrast agents inhibit fibrinolysis, although by poorly defined pathways. The purpose of this study was to define specific mechanisms by which contrast agents inhibit clot lysis. METHODS AND RESULTS: Diatrizoate (high osmolar ionic agent), ioxaglate (low osmolar ionic), and ioversol (nonionic) were studied in vitro. Diatrizoate inhibited clot lysis by 81.3+/-0.6% vs. control (p<0.001). Ioxaglate inhibited clot lysis by 41.7+/-11.9%, which was of borderline significance (p=0.07). Ioversol did not significantly inhibit clot lysis (14.9+/-11.5% decrease vs. control; p>0.3). Inhibition of fibrinolysis was not explained by the high osmolarities of contrast agents, by their iodine content, or by their effects on the amidolytic activities of t-PA, urokinase, or plasmin. However, plasminogen activation by t-PA, urokinase, or streptokinase was significantly inhibited by contrast agents. Diatrizoate, ioxaglate, and ioversol inhibited plasminogen binding to plasma clots by 51+/-4% (p<0.001), 30.1+/-4% (p<0.01), and 19.4+/-7% (p=0.07), respectively. Plasma clots formed in the presence of contrast agents were resistant to lysis by plasmin. Diatrizoate produced the most potent effect, inhibiting clot lysis by 40+/-5.7% (p<0.03). Contrast agents did not inhibit plasminogen binding to fibrin or plasmin-mediated fibrinolysis if they were added after clot formation. Contrast agents altered clot turbidity, an index of fibrin structure, if present during clot formation, but not if added to preformed clots. Contrast agents did not affect plasminogen activator inhibitor-1 or alpha(2)-antiplasmin function. CONCLUSIONS: Contrast agents inhibit clot lysis by inhibiting plasminogen activation and by disrupting interactions of plasminogen and plasmin with fibrin by altering fibrin structure. Significant variation in antifibrinolytic properties exists between different contrast agents.

Antifibrinolytic Agents↗
PubMed1995

Nephrotoxicity of ionic and nonionic contrast media in 1196 patients: a randomized trial. The Iohexol Cooperative Study.

The incidence of nephrotoxicity occurring with the nonionic contrast agent, iohexol, and the ionic contrast agent, meglumine/sodium diatrizoate, was compared in 1196 patients undergoing cardiac angiography in a prospective, randomized, double-blind multicenter trial. Patients were stratified into four groups: renal insufficiency (RI), diabetes mellitus (DM) both absent (N = 364); RI absent, DM present (N = 318); RI present, DM absent (N = 298); and RI and DM both present (N = 216). Serum creatinine levels were measured at -18 to 24, 0, and 24, 48, and 72 hours following contrast administration. Prophylactic hydration was administered pre- and post-angiography. Acute nephrotoxicity (increase in serum creatinine of > or = 1 mg/dl 48 to 72 hours post-contrast) was observed in 42 (7%) patients receiving diatrizoate compared to 19 (3%) patients receiving iohexol, P < 0.002. Differences in nephrotoxicity between the two contrast groups were confined to patients with RI alone or combined with DM. In a multivariate analysis, baseline serum creatinine, male gender, DM, volume of contrast agent, and RI were independently related to the risk of nephrotoxicity. Patients with RI receiving diatrizoate were 3.3 times as likely to develop acute nephrotoxicity compared to those receiving iohexol. Clinically severe adverse renal events were uncommon (N = 15) and did not differ in incidence between contrast groups (iohexol N = 6; diatrizoate N = 9). In conclusion, in patients undergoing cardiac angiography, only those with pre-existing RI alone or combined with DM are at higher risk for acute contrast nephrotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1989

Contrast nephrotoxicity: a randomized controlled trial of a nonionic and an ionic radiographic contrast agent.

Experimental studies have suggested that nonionic contrast agents are less nephrotoxic than ionic contrast agents. To examine the relative nephrotoxicity of the two types of agents, we randomly assigned 443 patients to receive either iopamidol (nonionic) or diatrizoate (ionic) for cardiac catheterization. The patients were stratified into low-risk (n = 283) or high-risk (n = 160) groups, on the basis of the presence of diabetes mellitus, heart failure, or preexisting renal insufficiency (base-line serum creatinine level, greater than 133 mumol per liter). Serum and urine analyses were performed at base line and 24 and 48 hours after the infusion of contrast material. Nephrotoxicity was defined as an increase in the serum creatinine level within 48 hours of at least 44 mumol per liter. The median maximal rise in the serum creatinine level was 18 mumol per liter in both the diatrizoate group (n = 235) and the iopamidol group (n = 208) (P not significant; power to detect a difference greater than 9 mumol per liter, greater than 90 percent). Creatinine levels increased by at least 44 mumol per liter (0.5 mg per deciliter) in 10.2 percent of the patients receiving diatrizoate and 8.2 percent of the patients receiving iopamidol (P not significant). Among the high-risk patients, creatinine levels increased by at least 44 mumol per liter in 17 percent of the patients in the diatrizoate group, as compared with 15 percent of the patients in the iopamidol group (P not significant). We were unable to demonstrate a difference in the incidence of nephrotoxicity between patients receiving a non-ionic contrast agent and those receiving an ionic contrast agent.

Cardiac Catheterization↗
PubMedDate not supplied

Metrizamide in experimental urography. V. Renal excretion mechanism of a non-ionic contrast medium in rabbit and cat.

The excretion mechanisms of the non-ionic contrast medium, metrizamide, and the ionic, sodium diatrizoate, are compared to investigate the potential usefulness of metrizamide in clinical urography. A mixture of 125I-labeled metrizamide and 131I-labeled diatrizoate was injected intravenously to rabbits or cats. Urine, bile and blood were analyzed for their concentration of iodine. From these concentrations the renal and total clearance was calculated. In the rabbit the excretion of metrizamide was also compared with that of 3H-inulin with or without influence of p-aminohippurate or probenecid. The earlier reported relatively low urinary iodine concentrations after intravenous injection to rabbits of low doses were explained by the following findings: In the rabbit the volume of distribution, the renal clearance and the total clearance of metrizamide were smaller than those measured for diatrizoate and inulin. The biological half-life in serum measured 30-150 min after injection was the same for all three compounds. No indication of tubular secretion was found. The excretion mechanism of the contrast media exhibits species differences as no differences between metrizamide and diatrizoate in the parameters mentioned above could be measured in the cat.

Aminohippuric Acids↗
PubMedDate not supplied

Direct and reflex myocardial effects of intracoronary administered contrast materials in the anesthetized and conscious dog: comparison of standard and newer contrast materials.

The direct and indirect actions on left ventricular dynamics of contrast material (sodium meglumine diatrizoate) currently used for coronary arteriography, modified ionic material (sodium meglumine calcium metrizoate) and non-ionic material (metrizamide) were assessed in conscious and anesthetized dogs. In both anesthetized and conscious animals, the diatrizoate compound caused an early (3--10 sec after injection) decrease in peak dp/dt and dp/dt/LVP40, followed by late (10--20 sec after injection) increases in these variables. The predominant early and later effects of the calcium metrizoate compound were increases in parameters of LV contractile state. Metrizamide produced no significant early alterations, but later induced a small increase in these variables. The positive inotropic actions of each of the contrast materials were attenuated by beta adrenergic blockade. The early effects of the contrast materials were similar in the presence of segmental ischemia. The late positive inotropic effects in response to the diatrizoate compound and metrizamide were not observed in the ischemic state, while the positive inotropic response induced by the calcium metrizoate compound was significantly reduced. Thus intracoronary administration of sodium meglumine diatrizoate produced direct myocardial depression, followed by adrenergically mediated myocardial stimulation. Calcium metrizoate caused prominent direct and adrenergically mediated augmentation in contractile state. Metrizamide induced the least alteration in LV contractile state.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Trapped plasma vs. osmolality in canine microcapillary hematocrits.

The trapped plasma in the packed red cell portion of the microcapillary hematocrit of hypertonic canine blood was measured with I-125 labelled albumin. Blood osmolalities were raised by the addition of sodium chloride and meglumine/sodium diatrizoate. The trapped plasma was 1.12 +/- 0.15%, 1.75 +/- 0.27% and 1.77 +/- 0.22% at 300, 580, and 723 mOsm/kg, respectively, for sodium chloride solutions. At 924 mOsm/kg some of the blood plus sodium chloride samples hemolyzed. In the group without hemolysis the trapped plasma was 5.84 +/- 1.35% while in the group with hemolysis it measured 12.43 +/- 1.90%. The trapped plasma with diatrizoate solutions was 1.41 +/- 0.11, 2.15 +/- 0.18 and 5.32 +/- 0.56 at 458, 531 and 602 mOsm/kg, respectively. Above an osmolality of 458 mOsm/kg the trapped plasma was significantly greater for the diatrizoate solutions than for the sodium chloride solutions. At osmolalities below 458 mOsm/kg only a small correction is needed for trapped plasma with either sodium chloride or meglumine/sodium diatrizoate solutions.

Animals↗
PubMed1989

Choice of contrast material for four-hour delayed contrast-enhanced computed tomography of the liver.

Four-hour delayed contrast-enhanced computed tomography (DCECT) shows promise for improved detection of focal liver lesions. No previous studies have examined the use of nonionic contrast materials for DCECT. The authors undertook a case-controlled study in monkeys to define the relative efficacies of iopamidol and diatrizoate for DCECT. In this model, diatrizoate made the liver significantly more opaque at four hours than did iopamidol (mean 126.5 vs 87.6 HU, P less than or equal to 0.05). Opacification of the gallbladder and biliary tract occurred more often and was denser with diatrizoate. The relative efficacies of biliary excretion correlate with similarities in molecular structure. While it has been shown that the increased density from DCECT with diatrizoate may allow detection of more metastatic lesions, the clinical utility of the inferior parenchymal density obtained with iopamidol, extrapolated to be approximately 11 to 14 HU in humans, remains to be-established.

Animals↗
PubMed1993

Effect of contrast material osmolality on the electrocardiogram during intrauterine injection.

RATIONALE AND OBJECTIVES: In a previous study, intrauterine injection of meglumine-sodium diatrizoate (high osmolar contrast media) during hysterosalpingography was found to induce lengthening of the QTc interval on electrocardiography. To evaluate the relationship between high osmolality and electrocardiographic changes during intrauterine injection, the authors evaluated the effect on QTc of two ionic contrast agents with different osmolality during routine hysterosalpingography. METHODS: Forty-eight women undergoing routine hysterosalpingography were included in the study. Thirty-two women received meglumine-sodium diatrizoate (1500 mOsm/kg) and 16 received meglumine-sodium ioxaglate (600 mOsm/kg). QTc changes were evaluated using a 12 lead computerized electrocardiogram system during all the stages of the procedure. RESULTS: In the meglumine-sodium diatrizoate group, QTc interval was prolonged significantly from 419 +/- 19 msec at baseline to 447 +/- 30 msec during injection of contrast material, P < .001, and returned to baseline values in late phase (416 +/- 18 msec). The meglumine-sodium ioxaglate group showed no change in the QTc interval. CONCLUSION: As the single major difference between the two ionic agents is osmolality, we believe that QTc interval prolongation in the meglumine-sodium diatrizoate group is related to increased osmolality.

Adult↗
PubMed1994

Cardiorespiratory responses elicited by right atrial injections of iodinated contrast media. Comparative evaluation of four agents.

RATIONALE AND OBJECTIVES: The purpose of this study is three-fold: 1) to quantify the cardiorespiratory responses to rapid right atrial injections of meglumine/sodium diatrizoate, ioxaglate, iotrolan, and iopamidol; 2) to compare the effects of each contrast medium to that of its corresponding vehicle and saline; and 3) to evaluate the role of the vagus nerve in the cardiorespiratory responses. METHODS: Seventeen anesthetized dogs, breathing spontaneously, were used. Injections of 2.0 mL/kg were given into the right atrium in 2 seconds. Each contrast medium, along with its vehicle and saline, was tested on 4 dogs (5 dogs for diatrizoate). Blood pressure, air flow, tidal volume, upper airway pressure, esophageal pressure, mean arterial pressure and heart rate, breathing frequency, dynamic lung compliance, upper airway resistance, and total lung resistance were recorded or calculated. RESULTS: Diatrizoate and its vehicle caused a significant increase in blood pressure, tidal volume, esophageal pressure, and a decrease in mean arterial pressure with an increase in heart rate. These responses were not mediated by vagal afferents. Ioxaglate and iotrolan, but not their vehicles, increased breathing frequency; this response was abolished by vagal block. Ioxaglate decreased mean arterial pressure and increased heart rate; the decrease in mean arterial pressure was still present during vagal block. Iopamidol and its vehicle did not alter respiratory parameters. Iopamidol, but not its vehicle, caused only a minimal and transient increase in mean arterial pressure before and during vagal block. None of the contrast media changed upper airway resistance, total lung resistance, and dynamic lung compliance. CONCLUSION: Both diatrizoate and its vehicle elicited the largest changes in respiratory and cardiovascular functions, not mediated by vagal afferents and caused by osmolality of the solution. Ioxaglate, iotrolan, and iopamidol induced smaller cardiorespiratory changes, mediated by vagal afferents. Their respective vehicles did not cause any effects, which suggests that the chemical structure plays a role. Nonionic contrast media elicited only minor and transient cardiorespiratory alterations.

Airway Resistance↗