Frequency of anaphylactoid reactions during intravenous urography with radiographic contrast media at two different temperatures

The relationship between iodinated contrast material temperature and adverse reactions: A meta-analysis of 307,329 injections

OBJECTIVE

The effect of iodinated contrast material (CM) temperature on injection pressures and viscosity has been well established. However, the effect of extrinsic warming of CM on allergic reactions and extravasations remains unclear. The purpose of this study is to compare the rates of allergic reactions and extravasations between warmed CM to room temperature CM.

METHODS

We conducted a comprehensive systematic search using PubMed, Embase, and Web of Science databases for all studies that assess the impact of warmed CM on adverse reactions. The primary outcomes of our study were allergic reaction and extravasation rates. We calculated weighted pooled odds ratios (OR) and 95% confidence intervals (CI) for all outcomes using the random-effects model. A P-value <0.05 was considered statistically significant. We conducted subgroup analyses based on the viscosity of the CM.

RESULTS

A total of five studies, including 307,329 CM injections (86,676 at room temperature and 220,653 warmed to 37 °C), were included in the analysis. For high viscosity CM, pre-warming was associated with significantly lower allergic reaction rates (OR: 0.59, 95% CI: 0.49-0.72, P < 0.00001). There was no significant difference in rates of extravasation for high viscosity CM (OR: 0.53, 95% CI: 0.20-1.43, P = 0.21).

DISCUSSION

Our meta-analysis suggests that warming CM to 37 °C is a safe and effective approach to reduce the risk of allergic reactions and physiologic reactions during injection of high-viscosity CM. However, there was no significant difference in extravasation rates between warmed and room temperature CM, regardless of viscosity.

Influence of Contrast Material Temperature on Patient Comfort and Image Quality in Computed Tomography of the Abdomen: A Randomized Controlled Trial

BACKGROUND

International guideline recommendations on safe use of contrast media (CM) are conflicting regarding the necessity to prewarm iodinated CM.

PURPOSE

Aim of the study was to evaluate the effects of room temperature CM compared with prewarmed CM on image quality, safety, and patient comfort in abdominal computed tomography (CT).

METHODS

CATCHY (Contrast Media Temperature and Patient Comfort in Computed Tomography of the Abdomen) is a double-blinded, randomized noninferiority trial. Between February and August 2020, 218 participants referred for portal venous abdominal CT were prospectively and randomly assigned to 1 of 2 groups. All patients received iopromide at 300 mg I/mL: group 1 at room temperature (~23°C [~73°F]) and group 2 prewarmed to body temperature (37°C [99°F]). A state-of-the-art individualized CM injection protocol was used, based on body weight and adapted to tube voltage. Primary outcome was absolute difference in mean liver attenuation between groups, calculated with a 2-sided 95% confidence interval. The noninferiority margin was set at -10 HU. Secondary outcomes were objective (signal-to-noise ratio and contrast-to-noise ratio) and subjective image quality; CM extravasations and other adverse events; and participant comfort (5-point scale questionnaire) and pain (numeric rating scale). This trial is registered with ClinicalTrials.gov (NCT04249479).

RESULTS

The absolute difference in mean attenuation between groups was + 4.23 HU (95% confidence interval, +0.35 to +8.11; mean attenuation, 122.2 ± 13.1 HU in group 1, 118.0 ± 15.9 HU in group 2; P = 0.03). Signal-to-noise ratio, contrast-to-noise ratio, and subjective image quality were not significantly different between groups (P = 0.53, 0.23, and 0.99 respectively). Contrast extravasation occurred in 1 patient (group 2), and no other adverse events occurred. Comfort scores were significantly higher in group 1 than in group 2 (P = 0.03); pain did not significantly differ (perceived P > 0.99; intensity P = 0.20).

CONCLUSIONS

Not prewarming iodinated CM was found noninferior in abdominal CT imaging. Prewarming conferred no beneficial effect on image quality, safety, and comfort, and might therefore no longer be considered a prerequisite in state-of-the art injection protocols for parenchymal imaging.

Effect of Extrinsic Warming of Low-Osmolality CT Contrast Media (Iohexol 350) on Extravasations and Patient Reaction Rates: A Retrospective Study

Background: Extrinsic warming of iodinated CT contrast media to body temperature reduces viscosity and injection pressures. However, studies examining the effect of extrinsic warming on clinical adverse events are limited in number and provide conflicting results. Therefore, consensus practice recommendations have been sparse. Objective: To compare rates of extravasation, allergic/allergic-like reactions, and physiologic reactions between iohexol 350 warmed to body temperature (37°C) and maintained at room temperature. Methods: This retrospective study compared adult patients who received CT examinations using IV iohexol 350 that had either been warmed to body temperature or maintained at room temperature. At our institution, contrast media had historically been warmed to body temperature prior to a protocol change unrelated to this investigation. Patient and CT examination characteristics were extracted from the electronic medical record. Adverse events, including extravasations, allergic/allergic-like reactions, and physiologic reactions, were compared between groups. Results: A total of 3939 patients received contrast media warmed to body temperature before the protocol change; 3933 patients received contrast media at room temperature after the protocol change. The body temperature group experienced 11 (0.28%; 95% CI 0.14%, 0.50%) adverse events, all extravasations; allergic/allergic-reaction rate was 0.00% (97.5% CI 0.00%, 0.09%). The room temperature group experienced 17 (0.43%; 95% CI 0.25%, 0.69%) adverse events [13 (0.33%; 95% CI 0.17%, 0.56%) extravasations; 4 (0.10%; 95% CI 0.03%, 0.26%) allergic/allergic-like reactions]. No physiologic reaction occurred in either group. The two groups were not different in terms of overall reaction rate (p=.19), extravasation rate (p=.69), allergic/allergic-like reaction rate (p=.06), or physiologic reaction rate (p>.99). Logistic regression adjusting for patient and CT characteristics (age, sex, conventional CT vs CTA, contrast media volume, injection location, needle gauge) showed no significant association of patient group and adverse reaction rate (odds ratio=2.19, 95% CI 0.68-7.00). Multivariable regression modeling demonstrated an excess of 0.27 adverse events per 100 patients within the room temperature group, below a 0.6% non-inferiority margin. Conclusion: The data suggest that maintaining iohexol 350 at room temperature is non-inferior to warming the agent to body temperature before injection. Clinical Impact: The resources involved to prewarm iohexol 350 before injection may not be warranted.

Extrinsic warming of low-osmolality iodinated contrast media to 37°C reduced the rate of allergic-like reaction

Background: Although there is good evidence that warming of contrast media changes the bolus kinetics and injection pressure of iodinated contrast media, there has been little evidence that it affects clinical adverse event rates in a meaningful way. Objective: To determine whether the extrinsic warming of low-osmolality iodinated contrast media to 37°C reduced adverse reactions. Methods: Data on adverse reactions were collected from two cohorts, one of which used contrast media at room temperature and the other in which contrast media were warmed to 37°C before administration. Adverse reactions, including allergic-like and physiological reactions, were reviewed. We compared the incidence rates of adverse reactions between the two cohorts by using the χ2 test. Results: A total of 70,446 injections in cohort 1 and 203,873 injections in cohort 2 were included. Extrinsic warming reduced the rate of allergic-like reactions to iopromide 370, iopamidol 370, and iohexol 350 (0.32% in cohort 1 versus 0.21% in cohort 2, p = 0.003; 0.14% versus 0.10%, p = 0.046; and 0.32% versus 0.13%, p = .003, respectively). However, the physiological reaction rates could not be reduced (p = 0.057, p = 0.107, and p = 0.962, respectively). The extrinsic warming of iopromide 300 could not reduce adverse reaction rates (allergic-like reaction rates: 0.21% versus 0.16%, p = 0.407; physiological reaction rates: 0.17% versus 0.13%, p = 0.504). Conclusion: Extrinsic warming to 37°C before intravenous administration was associated with a reduction in the rate of allergic-like reactions to iopromide 370, iopamidol 370, and iohexol 350.

Rate of contrast material extravasations and allergic-like reactions: effect of extrinsic warming of low-osmolality iodinated CT contrast material to 37 degrees C

PURPOSE

To retrospectively determine whether extrinsic warming of the low-osmolality contrast material iopamidol to 37°C prior to intravenous administration at computed tomography (CT) affects extravasation and allergic-like reaction rates.

MATERIALS AND METHODS

The need to obtain informed patient consent was waived for this HIPAA-compliant and institutional review board-approved analysis. All adverse events related to the intravenous administration of iopamidol during CT examinations occurring 200 days before (period 1) and 200 days after (period 2) the cessation of extrinsic contrast material warming (37°C) for intravenous injections of less than 6 mL/sec at Duke University Medical Center (Durham, NC) were retrospectively reviewed. Adverse event rates were compared by using χ2 statistics.

RESULTS

There were 12,682 injections during period 1 (10,831 injections of iopamidol 300 and 1851 injections of iopamidol 370) and 12,138 injections (10, 064 injections of iopamidol 300 and 2074 injections of iopamidol 370) during period 2. Adverse event rates for iopamidol 300 were not affected by extrinsic warming (extravasation rates: 0.30% [32 of 10,831] in period 1 vs 0.23% [23 of 10,064] in period 2, P=.64; allergic-like reaction rates: 0.39% [42 of 10,831] in period 1 vs 0.46% [46 of 10,064] in period 2, P=.74; overall adverse events: 0.68% [74 of 10,831] in period 1 vs 0.69% [69 of 10,064] in period 2, P=.99). Discontinuation of extrinsic warming was associated with significantly increased extravasation and overall adverse event rates for iopamidol 370 (extravasation rates: 0.27% [five of 1851] vs 0.87% [18 of 2074], P=.05; allergic-like reaction rates: 0.16% [three of 1851] vs 0.39% [eight of 2074], P=.42; overall adverse events: 0.43% [eight of 1851] vs 1.25% [26 of 2074], P=.02).

CONCLUSION

Extrinsic warming (to 37°C) does not appear to affect adverse event rates for intravenous injections of iopamidol 300 of less than 6 mL/sec but is associated with a significant reduction in extravasation and overall adverse event rates for the more viscous iopamidol 370.

Temperature effect on nausea during fluorescein angiography

PURPOSE

Nausea is the most common adverse effect of fluorescein angiography (FA). Warming of fluorescein dye before injection has been reported anecdotally to decrease nausea frequency. We examined the effect of warmed fluorescein dye on the frequency of adverse effects of FA.

DESIGN

Prospective, randomized, controlled trial.

PARTICIPANTS

Five hundred forty-seven angiograms performed on 394 patients; 273 were in the control group and 274 were in the study group.

METHODS

Patients were alternately assigned to FA using dye at room temperature (control group) or dye prewarmed to body temperature (study group). All patients were masked to the dye temperature. After FA, patients were questioned regarding any adverse effects experienced.

MAIN OUTCOME MEASURES

Presence or absence of reported nausea associated with FA.

RESULTS

Adverse reactions were reported for 39 of the angiograms (7.1%), including 32 procedures for which nausea was reported (5.9%). No significant difference in the frequency of adverse reactions was found between the two groups (P = 0.41). No significant difference in the frequency of nausea was found between the two groups (P = 0.28). The sample sizes used allow an 80% power for detecting a clinically significant difference of 4% adverse effects in one group and 10% in the other group when testing at a significance level of 5%.

CONCLUSIONS

Warming of fluorescein dye does not significantly alter the incidence of nausea reported with FA.

Plasma leukotriene C4 and reactions to contrast media

Forty-five patients were randomly divided into three groups of 15 and within each group patients were given iothalamate, iopamidol or ioxaglate intravenously during radiological investigations. The plasma leukotriene C4 level was measured before and 30 s and 3 min after the administration of the respective contrast media. In patients demonstrating non-idiosyncratic contrast reactions, a consistent decrease in plasma leukotriene concentration was noted at both 30 s and 3 min following the administration of all three contrast media. A statistically significant decrease in plasma leukotriene occurred at 30 s with ioxaglate, but not with the other two agents. In the limited number of patients who experienced idiosyncratic reactions, the decrease in plasma leukotriene concentration was less apparent. This decrease in plasma leukotriene concentration has been attributed to changes in plasma volume following administration of hyperosmolar contrast media. The inability to demonstrate an increase in plasma leukotriene levels following the administration of both conventional and new, low-osmolar radiographic contrast media supports the cumulative evidence against an allergic mechanism in the majority of non-idiosyncratic and some idiosyncratic contrast reactions.

Anaphylaxis: pathophysiology, clinical presentations and treatment

Anaphylaxis and anaphylactoid reactions are abrupt, often life-threatening episodes, secondary to the liberation of certain chemical mediators, and their effects on target organs. The number of agents known to trigger such reactions is expanding, with the most common fatal reactions secondary to penicillins, iodinated contrast material (ICM), and hymenoptera stings. Limited studies point to upper airway obstruction and circulatory collapse as the causes of death in man. It is felt that the frequency of cardiovascular involvement is not widely appreciated, and that hypotensive patients can be markedly hypovolemic. The primary goals of treatment should be aimed at preventing or reversing complications, and include immediate attention to the airway, cardiac monitoring, and establishment of intravenous access. The cornerstone of pharmacologic therapy is epinephrine. A comprehensive review of the pathophysiology, symptomatology, and treatment is presented.