Exploring Intra-arterial Contrast Administration for Intraoperative Imaging Using a Swine Model.

Intraoperative computed tomography (CT) imaging with endovascular delivery of intra-arterial (IA) contrast could potentially provide higher attenuation with lower contrast volumes than intravenous (IV) administration. We aimed to compare IA and IV contrast use for organ-specific CT abdominal imaging. Five anesthetized swine had external jugular and brachial artery access with ascending aortic pigtail placement. An IV protocol was 100 mL at 5 mL/sec over 20 sec vs 50 mL of IA contrast at 5 mL/sec over 10 sec. Region-of-interest markers were applied to anatomical regions to measure attenuation (HU) over time. IA and IV contrast protocols achieved adequate aortic opacification (IA, 455 ± 289 vs IV, 450 ± 114 HU). The IA contrast aortic attenuation curve reached peak attenuation compared with IV contrast (IA, 8 vs 23 sec; P < .001). Time to peak attenuation was similar between IA and IV contrast in the portal vein (IA, 38 vs IV, 42 sec, P = .25). IA administration achieved a superior contrast-to-noise ratio (CNR) in less time compared with IV (R2 = .94; P < .001). IA contrast achieved adequate opacification with less bolus broadening and a superior CNR compared with IV contrast while using a smaller contrast volume for directed organ-directed imaging.

An Intraoperative Episode of Severe Type II Renal Tubular Acidosis in an 83-Year-Old Woman.

Type II renal tubular acidosis (RTA) is a rare defect in bicarbonate transport that can cause serious metabolic derangements. We report the case of a spontaneous, isolated intraoperative episode of severe type II RTA in an elderly woman who presented for radical neck dissection, mandible excision, and flap creation. Intraoperatively, she developed a stark metabolic acidosis with hypokalemia, progressively worsening base excess, and prolific urine output. Aggressive resuscitation with bicarbonate corrected all metabolic abnormalities. There was no identifiable trigger and the patient was successfully discharged with no further recurrences during hospitalization. The inability to identify the clinical presentation of RTA perioperatively can lead to poor outcomes.

Emergency medical services operations during civil unrest: Best practices from lessons learned.

During periods of civil unrest, emergency medical services (EMSs) clinicians will be called upon to provide care to those impacted, including those who are actively instigating violence. Working during periods of civil unrest poses significant operational and security challenges to EMS leadership and clinicians. This review provides best practices for EMS operating during periods of civil unrest through analysis of after action reports from Baltimore, Maryland; Charlottesville, North Carolina; Minneapolis, Minnesota; and Washington, DC.

The functional vascular anatomy of the swine for research.

OBJECTIVES: Swine (Sus Scrofa) are utilized broadly in research settings, given similarities to human vessel size and function; however, there are some important differences for clinicians to understand in order to interpret and perform translational research. This review article uses angiograms acquired in the course of a translational research program to present a description of the functional anatomy of the swine. METHODS: Digital subtraction angiography and computed tomography angiography were obtained throughout the course of multiple studies utilizing power injection with iodinated contrast. Subtracted two-dimensional images and three-dimensional multiplanar reformations were utilized post image acquisition to create maximal intensity projections and three-dimensional renderings of using open-source software (OsiriX). These imaging data are presented along with vessel measurements for reference. RESULTS: An atlas highlighting swine vascular anatomy, with an emphasis on inter-species differences that may influence how studies are conducted and interpreted, was compiled. CONCLUSIONS: Swine are utilized in broad-reaching fields for preclinical research. While many similarities between human and swine vasculature exist, there are important differences to consider when conducting and interpreting research. This review article highlights these differences and presents accompanying images to inform clinicians gaining experience in swine research.

Measuring Cardiac Output in a Swine Model.

Swine are frequently used in medical research given their similar cardiac physiology to that of humans. Measuring cardiac parameters such as stroke volume and cardiac output are essential in this type of research. Contrast ventriculography, thermodilution, and pressure-volume loop (PV-loop) catheters can be used to accurately obtain cardiac performance data depending on which resources and expertise are available. For this study,five Yorkshire swine were anesthetized and intubated. Central venous and arterial access was obtained to place the necessary measurement instruments.A temperature probe was placed in the aortic root. A cold saline bolus was delivered to the right atrium and temperature deflection curve was recorded. Integration of the area under the curve allowed for the calculation of the current cardiac output.A pigtail catheter was percutaneously placed in the left ventricle and 30 mL of iodinated contrast was power injected over 2 seconds. Digital subtraction angiography images were uploaded to volumetric analysis software to calculate the stroke volume and cardiac output. A pressure volume-loop catheter was placed into the left ventricle (LV) and provided continuous pressure and volume data of the LV, which allowed the calculation of both stroke volume and cardiac output.All three methods demonstrated good correlation with each other. The PV-loop catheter and thermodilution exhibited the best correlation with a 3% error and a Pearson coefficient of 0.99, with 95% CI=0.97 to 1.1, (p=0.002). The PV-loop catheter against ventriculography also showed good correlation with a 6% error and a Pearson coefficient of 0.95, 95% CI=0.96 to 1.1 (p=0.01). Finally, thermodilution against ventriculography had a 2% error with r=0.95, 95% CI=0.93 to 1.11, (p=0.01). In conclusion, we state that the PV-loop catheter, contrast ventriculography, and thermodilution each offer certain advantages depending on the researcher's requirements. Each method is reliable and accurate for measuring various cardiac parameters in swine such as the stroke volume and cardiac output.

Utility of the DIVA score for experienced emergency department technicians.

BACKGROUND: The DIVA score is validated for predicting success of the initial attempt at peripheral intravenous insertion by nurses and physicians. A score of 4 or greater is 50% to 60% likely to have a failed first attempt. The study objective was to assess the validity of this score for emergency department technicians. METHODS: This study used a prospective convenience sample of 181 children presenting to the emergency department with intravenous access attempt by one of 29 emergency department technicians. DIVA score, total number of attempts, and median time to successful intravenous cannulation were obtained. RESULTS: Comparing patients with a DIVA score <4 to ≥4, first-time IV placement failure rates were lower (9% [95% CI, 3-24] vs. 41% [95% CI, 33-49]) and median time to IV placement was shorter (75 [interquartile range (IQR) 42-157] vs. 254 [IQR 91-806]) seconds. In patients with scores ≥4, emergency department technicians with ≥5 years of experience were significantly more likely to be successful on the first attempt (OR 2.8; 95% CI, 1.03-7.63). For every year of technician experience, the time to catheter placement, adjusted for DIVA score, decreased by 25 minutes (P≤0.05, R2=0.05). Comparing our receiver operating curve to the derivation study, the areas were similar (0.67 vs. 0.65). CONCLUSIONS: This study provides preliminary evidence for the validity of the DIVA score when applied to IVs placed by emergency department technicians. For patients with high DIVA scores, ≥5 years of IV experience was associated with higher odds of successful first-time IV placement and shorter time to placement. HIGHLIGHTS The difficult intravenous access (DIVA) score may be generalizable to IVs placed by experienced emergency department technicians (EDTs) Higher odds of first-time success in difficult patients with ≥5 years EDT experience Early identification of difficult access may allow for aid of alternative technology Likely first study to evaluate EDTs IV skills in patients with varying DIVA scores.