Hidenori Tanabe

Using Ultrasonography for Vessel Diameter Assessment to Prevent Infiltration.

Small veins are a risk factor for infiltration. However, there are no data regarding the ideal vein diameter for preventing infiltration. Using ultrasound, vessel diameter and calculated ratios of the vessel diameter to the catheter gauge were measured. The relationship between the ratio and infiltration was assessed to establish a cutoff point. The mean ratio of the infiltration group was significantly smaller than that of the no-infiltration group (P < .01), and the ratio was an independent risk factor according to the multivariable analysis. The ratio of 3.3 was determined to be the cutoff point that enables health care professionals to identify veins appropriately.

Low-temperature infiltration identified using infrared thermography in patients with subcutaneous edema revealed ultrasonographically: A case report.

Infiltration is a frequent complication of infusion therapy. We previously demonstrated the usefulness of infrared thermography as an objective method of detecting infiltration in healthy people. However, whether thermography can detect infiltration in clinical settings remains unknown. Therefore, we report two cases where thermography was useful in detecting infiltration at puncture sites. In both cases, tissue changes were verified ultrasonographically. The patients were a 56-year-old male with cholangitis and a 76-year-old female with hepatoma. In both cases, infiltration symptoms such as swelling and erythema occurred one day after the insertion of a peripheral intravenous catheter. Thermographic images from both patients revealed low-temperature areas spreading from the puncture sites; however, these changes were not observed in other patients. The temperature difference between the low-temperature areas and their surrounding skin surface exceeded 1.0°C. Concurrently, ultrasound images revealed that tissues surrounding the vein had a cobblestone appearance, indicating edema. In both patients, subcutaneous tissue changes suggested infiltration and both had low-temperature areas spreading from the puncture sites. Thus, subcutaneous edema may indicate infusion leakage, resulting in a decrease in the temperature of the associated skin surface. These cases suggest that infrared thermography is an effective method of objectively and noninvasively detecting infiltration.

Low-angled peripheral intravenous catheter tip placement decreases phlebitis

Introduction Peripheral intravenous catheters (PIVCs) are frequently removed due to phlebitis. We hypothesized that catheters made of polyurethane, which is more flexible than Teflon, would decrease phlebitis, and that flexibility could be estimated by measuring the catheter-tip angle. Ultrasonography in two groups of patients with different catheter types was then used to compare catheter-tip angles and phlebitis. Methods Observational studies were carried out at a medical ward in a university hospital. Infusion therapy was administered to one group of patients in 2014 using Teflon catheters (control group, n = 200), and to another group of patients in 2015 using polyurethane catheters (investigational group, n = 207). The symptoms were assessed according to a scale developed by the Infusion Nurses Society. Long-axis ultrasonography images taken immediately before catheter removal were used to measure the angle between the central line of the catheter within 2 mm from the distal point and a tangent to the vessel wall. Results There were no significant differences between the two groups with respect to sex, age, and medical diagnosis. In the control and investigational groups, the rates of phlebitis were 37% (73/200) and 17% (36/207), respectively (p<0.001). The median angles of the catheter tip were 7.8° and 4.1°, respectively (p<0.001). Phlebitis occurred more frequently when the catheter-tip was placed at angle >5.8°. Discussion The frequency of phlebitis was lower in the polyurethane, in which the catheter was placed at lower angle, almost parallel to the vessel. Our results will aid in developing new catheters and in improving PIVC-securement techniques.

The relationship between the tip position of an indwelling venous catheter and the subcutaneous edema

The present observational study aimed to clarify the relationship between the tip position of an indwelling venous catheter and the subcutaneous edema using ultrasonography images. Data were obtained before catheter removal in a medical ward of a university hospital in Tokyo, Japan. Two hundred peripheral intravenous catheters (PIVCs) from 154 patients were observed just before removal. We analyzed data for 194 PIVCs from 150 patients. Subcutaneous edema was observed in 43.8% of ultrasonography images. According to the univariate analysis, insertion site, PIVC tip contact with the vessel wall, and irritant drugs presence were selected as independent variables for logistic regression analysis. Both irritant drug and PIVC tip contact were associated with the presence of subcutaneous edema [adjusted odds ratio (OR) = 2.68, 95% confidence interval (CI) = 1.14-6.33; and OR = 2.01, 95% CI = 1.04-3.88, respectively]. To the best of our knowledge, this is the first study to use ultrasonography to simultaneously observe PIVC tip position and subcutaneous edema. Using ultrasonography to observe PIVC may be a useful method to understand these mechanisms. Medical staff should select an appropriate vein and indwelling catheter to avoid contact of PIVC tip with the vessel wall. Further studies exploring the causality of the relationship between subcutaneous edema, catheter placement, and thrombus formation is required. In addition, further development of nursing skills and medical devices to reduce mechanical stress is required.

Impact of Squeezing Condition to Obtain Sufficient Blood Volume for Self-Monitoring of Blood Glucose Using an Automatic Puncturing and Sampling System:

Blood sampling for self-monitoring of blood glucose is difficult for the elderly with low dexterity. We developed and tested the utility of an automatic puncturing and sampling (APS) system as a part of an automatic SMBG device, but success rates of securing sufficient blood volume was low (61.9%). Thus, the squeezing condition was changed to increase its success rate. The aim of this study is to investigate the impact to the amount of bleeding by making changes to the squeezing condition. In our previous experiment, blood sampling was performed simultaneously with squeezing, whereas the present study tested blood sampling after squeezing. This method increased the success rate (75%) among eight subjects who had a low success rate (25%) in the previous experiment using the APS system.

Exploring the causes of peripheral intravenous catheter failure based on shape of catheters removed from various insertion sites

The risk of peripheral intravenous catheter failure varies according to the insertion site. This study examined catheter shape just after removal to evaluate the causes of catheter failure according to site. This study was a secondary analysis of previous study data. Our observational study was conducted during a 6-month period at The University of Tokyo Hospital. Participants were hospitalized adults who received infusion therapy via a short peripheral catheter. We acquired ultrasound images of blood vessels and surrounding tissues at the catheter insertion site before catheter removal and clinical images of the removed catheters. We analyzed 184 catheters from 142 participants. There were no significant differences in the catheter failure rate (29.9%) among insertion sites. Curvature in the middle of the catheter was present in 9.2% of cases; the median bend angle at the catheter base was 9.1° (range: 0.0°-68.3°). The bend angle of catheters inserted in the upper arm was significantly greater than of catheters in the forearm (p = 0.013). Catheter curvature was related to catheter failure (14.8% of failed catheters had curvature; p = 0.035) and occlusion (35.3% of occluded catheters had curvature; p = 0.008) in upper arm and forearm placements. The median distance from the elbow to the insertion site was shorter for failed catheters than for surviving catheters. To prevent catheter failure, especially occlusion resulting from catheter curvature, a catheter should be inserted at an appropriate insertion site far from the antecubital fossa.

Is Thrombus With Subcutaneous Edema Detected by Ultrasonography Related to Short Peripheral Catheter Failure? A Prospective Observational Study

Short peripheral catheter (SPC) failure is an important clinical problem. The purpose of this study was to clarify the relationship between SPC failure and etiologies such as thrombus, subcutaneous edema, and catheter dislodgment using ultrasonography and to explore the risk factors associated with the etiologies. Two hundred catheters that were in use for infusion, excluding chemotherapy, were observed. Risk factors were examined by logistic regression analysis. Sixty catheters were removed as the result of SPC failure. Frequency of thrombus with subcutaneous edema in SPC failure cases was significantly greater than in those cases where therapy was completed without complications (P < .01). Multivariate analysis demonstrated that 2 or more insertion attempts were significantly associated with thrombus with subcutaneous edema. Results suggest that subsurface skin assessment for catheterization could prevent SPC failure.

Evaluation of the Predictive Validity of Thermography in Identifying Extravasation With Intravenous Chemotherapy Infusions

Early detection of extravasation is important, but conventional methods of detection lack objectivity and reliability. This study evaluated the predictive validity of thermography for identifying extravasation during intravenous antineoplastic therapy. Of 257 patients who received chemotherapy through peripheral veins, extravasation was identified in 26. Thermography was performed every 15 to 30 minutes during the infusions. Sensitivity, specificity, positive predictive value, and negative predictive value using thermography were 84.6%, 94.8%, 64.7%, and 98.2%, respectively. This study showed that thermography offers an accurate prediction of extravasation.

Continuous thermographic observation may predict extravasation in chemotherapy-treated patients

PURPOSE Extravasation, or leakage of vesicant drugs into subcutaneous tissues, causes serious complications such as induration and necrosis in chemotherapy-treated patients. As macroscopic observation may overlook symptoms during infusion, we focused on skin temperature changes at puncture sites and studied thermographic patterns related to induration or necrosis caused by extravasation. METHODS Outpatients undergoing chemotherapy using peripheral intravenous catheters were enrolled in this prospective observational study. We filmed and classified infrared thermography movies of puncture sites during infusion; ultrasonography was also utilized at puncture sites to observe the subcutaneous condition. Multiple logistic regression analysis was performed to examine the association of thermographic patterns with induration or necrosis observed on the next chemotherapy day. Differences in patient characteristics, puncture sites, and infusions were analyzed by Mann-Whitneys U test and Fishers exact test according to thermographic patterns. RESULTS Eight patients developed induration among 74 observations in 62 patients. Among six thermographic patterns, a fan-shaped lower temperature area gradually spreading from the puncture site (fan at puncture site) was significantly associated with induration. Ultrasonography revealed that catheters of patients with fan at puncture site remained in the vein at the end of infusion, indicating that the infusion probably leaked from the puncture site. Patients with fan at puncture site had no significant differences in characteristics and infusion conditions compared with those with the other five thermographic patterns. CONCLUSION We determined that fan at puncture site was related to induration caused by extravasation. Continuous thermographic observation may enable us to predict adverse events of chemotherapy.