Change the preprocedural fasting policy for contrast-enhanced CT: results of 127,200 cases

Policies and Practices Regarding Preparative Fasting for Contrast-Enhanced Computed Tomography: A Nationwide Survey

OBJECTIVES

To evaluate current policies and practices regarding preparative fasting before contrast-enhanced computed tomography (CECT) and the knowledge and attitudes of radiology head nurses.

METHODS

Radiology head nurses in 499 Chinese hospitals participated in an online survey on preparative fasting for CECT, which mainly included current departmental policies and practices and their knowledge and attitudes.

RESULTS

Response rate was 89.8% (448/499). All surveyed hospitals established preparative fasting protocols, mainly based on guidelines for iodinated contrast media (ICM) usage (68.8%). For the nongastrointestinal CECT scan, the most frequent fasting duration for solid food, semiliquid diet, liquid diet, and clear liquids was 4 to 6 hours (215/422 [50.9%]), less than 6 hours (332/396 [83.8%]), less than 6 hours (275/320, 85.9%), and less than 6 hours (151/189 [79.9%]), respectively. Forty-six percent of the respondents confirmed that unnecessary excessive fasting existed in practice, and the related patient discomfort occurred in 60.3% of the hospitals, mainly manifested as hypoglycemia (86.7%). Expert consensus and guidelines for iodinated contrast media usage (75%) were the leading approach to gain knowledge about preparative fasting; 90.6% of the respondents believed that the clinical scenarios requiring preparative fasting were the upper abdominal examinations. A majority of respondents (72.1%) believed that the current preparative fasting policies needed improvement.

CONCLUSION

Preparative fasting policies varied among hospitals in terms of the fasting content and duration. Respondents' opinions differed on fasting requirements based on various CECT examination sites and patients. The latest guideline regarding no fasting before CECT has not been fully adopted. Further research is required to promote the transformation of guideline evidence.

Fasting before contrast-enhanced CT and the incidence of acute adverse reactions: a single-center randomized clinical trial

OBJECTIVES

To evaluate the effect of eliminating the traditional preparatory fasting policy before contrast-enhanced CT on acute adverse reactions and to identify potential risk factors in a Spanish population sample, since many European patients still experience this unnecessary measure in clinical practice.

METHODS

Outpatients who underwent non-emergency CT to either 6 h of solid food fasting (control group) or an unrestricted consumption of solids (intervention group). Adverse reactions during contrast media administration and up to 30 min afterward were recorded and their incidence was calculated. Using univariate and multivariate logistic regression analyses, various patient-related and technical factors were evaluated to identify risk factors for nausea and vomiting.

RESULTS

One thousand one hundred three patients were evaluated, 560 patients in the control group, and 543 patients in the intervention group. Moderate and severe acute adverse reactions were not identified in either group. No statistical difference was found in the overall acute adverse reactions (hypersensitivity and chemotoxicity) incidence between groups (3.21% vs 2.30% p = 0.36). The total incidence of emetic adverse reactions (nausea and vomiting) was significantly lower in the intervention group than in the control group (0.92% vs 2.86% p = 0.02). Multivariate logistic regression analysis revealed that fasting, age, allergies, neurological diseases, and contrast media concentration were independent risk factors for nausea and vomiting.

CONCLUSION

Unrestricted food intake did not increase the overall incidence of acute adverse reactions and diminished the incidence of nausea and vomiting.

TRIAL REGISTRATION

ANZCTR, ACTRN12623000071628. Registered 23 January 2023-retrospectively registered, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=384985&showOriginal=true&isReview=true .

CRITICAL RELEVANCE STATEMENT

This randomized clinical trial carried out in adults undergoing a non-emergent CT scan demonstrates that fasting as a preparation before a contrast-enhanced CT scan should be discontinued and reserved only for certain specific imaging tests.

KEY POINTS

Despite low osmolar CT contrast media becoming ubiquitous, preparatory fasting is still widely practiced. The overall incidence of acute adverse reactions was unchanged after abolishing preparative fasting. Traditional preparatory fasting should be discontinued and reserved only for certain specific imaging tests.

Relationship between fasting prior to contrast-enhanced CT and adverse reaction in patients with allergies history

AIM

To examine the relationship between fasting prior to contrast-enhanced CT (CECT) and adverse reaction (AR) in patients with allergies history.

MATERIALS AND METHODS

Patients with allergies history who underwent CECT from January 2014 to December 2020 (713 cases with iodinated contrast media (ICM)-related allergy history and 27045 cases with unrelated allergies history) were retrospectively analyzed. The occurrence of ICM-related AR and patient information were recorded. The relationship between fasting and AR and emetic complications was analyzed.

RESULTS

There was no statistical difference in the overall incidence of AR and emetic complications between fasting group and non-fasting group (P>0.05) and fasting was not an influence factor for overall AR occurrence in patients with both ICM-related and unrelated allergies history. However, the incidence of severe AR in fasting group was higher than that in non-fasting group (P=0.01) in patients with unrelated allergies history. The AR incidence in fasting group was higher than that in non-fasting group (P=0.022) when receiving abdominal examinations in patients with unrelated allergies history. There was no statistical difference in the incidence of AR with different occurrence time between fasting group and non-fasting group (P>0.05) in patients with both ICM-related and unrelated allergies history.

CONCLUSIONS

Fasting was associated with higher incidence of severe AR and was associated with higher AR incidence when receiving abdominal examinations in patients with unrelated allergies history. Fasting did not have effects on the occurrence time of AR in patients with allergies history. These provided new guidance for usage of ICM in patients with allergies history.

Effects of Fasting versus Non-Fasting on Emetic Complications in Radiological Examinations Using Intravascular Non-Ionic Iodinated Contrast Media: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare the incidence of aspiration pneumonia, nausea, and vomiting after intravascular administration of non-ionic iodinated contrast media (ICM) between patients who fasted before contrast injection and those who did not.

MATERIALS AND METHODS

Ovid-MEDLINE and Embase databases were searched from their inception dates until September 2022 to identify original articles that met the following criteria: 1) randomized controlled trials or observational studies, 2) separate reports of the incidence of aspiration pneumonia, nausea, and vomiting after intravascular injection of non-ionic ICM, and 3) inclusion of patients undergoing radiological examinations without fasting. A bivariate beta-binomial model was used to compare the risk difference in adverse events between fasting and non-fasting groups. The I² statistic was used to assess heterogeneity across the studies.

RESULTS

Ten studies, encompassing 308013 patients (non-fasting, 158442), were included in this meta-analysis. No cases of aspiration pneumonia were reported. The pooled incidence of nausea was 4.6% (95% confidence interval [CI]: 1.4%, 7.8%) in the fasting group and 4.6% (95% CI: 1.1%, 8.1%) in the non-fasting group. The pooled incidence of vomiting was 2.1% (95% CI: 0.0%, 4.2%) in the fasting group and 2.5% (95% CI: 0.7%, 4.2%) in the non-fasting group. The risk difference (incidence in the non-fasting group-incidence in the fasting group) in the incidence of nausea and vomiting was 0.0% (95% CI: -4.7%, 4.7%) and 0.4% (95% CI: -2.3%, 3.1%), respectively. Heterogeneity between the studies was low (I² = 0%-13.5%).

CONCLUSION

Lack of fasting before intravascular administration of non-ionic ICM for radiological examinations did not increase the risk of emetic complications significantly. This finding suggests that hospitals can relax fasting policies without compromising patient safety.

Stratified assessment and warning regimen for prevention of acute adverse reactions to iodinated contrast media: results of 150,343 cases in a tertiary hospital

For contrast-enhanced CT examinations, there is a lack of comprehensive optimal management strategies of risk factors to reduce the risk of iodinated contrast media (ICM)-induced acute adverse reactions (AAR). Here, we determine the relationship between the rate of ICM-AAR and a stratified assessment and warning (SAW) regimen, which integrated risk identification, stratification, early warning, and prevention. A total of 120,822 cases in the conventional assessment period (58 years ± 15, 55.25% men) and 150,343 cases (58 years ± 14, 55.83% men) in the SAW period were enrolled. The results showed that the total AAR incidence in the SAW period (414/150,343, 0.28%) was lower than that in the conventional assessment period (506/120,822, 0.42%, P < 0.001), in which the proportion of AAR patients decreased by one-third. It mainly presented as decreases in mild and moderate reactions (P < 0.001), and a decrease in the proportion of moderate AAR patients (P = 0.001). Subgroup analysis showed lower mild and moderate AAR incidence in patients with different risk levels and with different ICM injection parameters following SAW regimen. We concluded that SAW regimen was associated with lower incidence of mild and moderate AAR, and decreased proportion of moderate AAR patients, which held potential for improved ICM safety.

Hemodynamic effects of intravenous bolus injection of iopromide 370 twice in abdominal contrast-enhanced CT and coronary CTA dual-site sequential examinations

Little information is available about how intravenous bolus injection of iopromide 370 twice in a short time will affect hemodynamics and whether the changes reach clinically relevant levels. In the present study, 31 healthy adult volunteers received abdominal contrast-enhanced CT and coronary CTA sequential examinations. The same dose and rate of normal saline was injected 30 min in advance as self-control. Hemodynamic data were noninvasively collected at selected time points from 1 min prior to injection to 30 min post-injection. The results showed that after iopromide 370 injection, except for stroke volume, all other indicators changed immediately during the first injection, changed most significantly during the second injection (P < 0.05), and returned to baseline within 10 min. Heart rate and cardiac output exhibited the most pronounced changes, with an increasing rate of 33.5% and 33.8%, respectively. For indicators with a change range of > 15% during the second injection, except for mean arterial pressure and total peripheral resistance, the proportions of subjects for the other indicators between the two groups were statistically different (P < 0.05). In conclusion, intravenous bolus injection of iopromide 370 twice in dual-site sequential examinations induced dose-cumulative and time-dependent hemodynamic effects, which all fluctuated within the normal ranges.