Effectiveness of ultrasonography for peripheral catheter insertion and catheter failure prevention in visible and palpable veins.

BACKGROUND: The increase in the success rate of peripheral intravenous catheterization against a difficult intravenous access (DIVA) using ultrasonography is reported; however, reports related to the effectiveness of using ultrasonography in increasing the success rate for visible and palpable veins is limited. Furthermore, according to a previous study, first attempt success in catheterization contributes to low catheter failure incidence. Thus, we developed a catheterization method using ultrasonography for peripheral veins including visible and palpable veins. This study investigates the effectiveness of ultrasonography use in improving the success rate of catheterization and preventing the catheter failure for peripheral veins including visible and palpable veins. METHODS: Adult inpatients were recruited. Trained nurses inserted intravenous catheters using ultrasonography. Ultrasonography was used for all vein assessment, target vein selection, and puncturing (i.e. target point selection and/or needle guidance), regardless of the target vein's visibility or palpability. Catheters with over a 24-h dwelling time were followed for catheter failure incidence. RESULTS: Thirty-one patients were recruited, and they required 34 catheterizations. Total number of catheterization attempts were 39. Of the peripheral veins, 51.3% (20/39) were visible and palpable, 48.7% (19/39) were DIVA. The rate of successful intravenous cannulation was 29 of 34 (85.3%) after one attempt and 4 of 34 (total 97.0%) after two attempts. The catheterization failure incidence was 3.2% (1/31) in the catheter that had an over 24-h dwelling time. CONCLUSIONS: Using ultrasonography to all target veins might have contributed to higher success rates of catheterization and extremely low incidence of catheter failure based on objective findings. Selecting the vein with larger diameters and healthy tissue as puncture point and showing center of vessel lumen clearly using ultrasonography might have been contributed the results.

Verification study on the catheterization of an upper arm vein using the new long peripheral intravenous catheter to reduce catheter failure incidence: A randomized controlled trial.

Intravenous infusion using a peripheral intravenous catheter (PIVC) is often complicated by catheter failure (CF). We hypothesized that catheterization of an upper arm vein instead of a forearm vein may help prevent CF. This study was designed to compare the incidence of CF in patients receiving hyper-stimulant drugs when catheters are placed in the forearm using short PIVCs (SPCs) with that when catheters are placed in the upper arm using the new long PIVCs. Patients admitted to a university hospital in Tokyo, Japan were enrolled in this study and were assigned to the SPC or the new long PIVC group. The primary outcome was the incidence of CF until 7 days. The secondary outcomes were the number of CFs per 1,000 days, the duration of the indwelling catheter, and the presence of thrombi and subcutaneous edema. Forty-seven patients were analyzed (median age, 67.0 years). The incidence of CF was 0% in the new long PIVCs and 32.0% (8 catheters) in the SPCs (p = 0.007), and the number of CF per 1,000 days was 0/1,000 and 81.7/1,000 days, respectively (p = 0.001). A significant difference in the duration of the indwelling catheter until CF occurrence was observed between the two groups (p = 0.004). Thrombi and subcutaneous edema were observed more frequently in the SPC group (p < 0.001). Catheterization of an upper arm vein using the new long PIVC to administer a hyper-stimulant drug might reduce CF compared with catheterization of a forearm vein using SPC.

Safety verification of a new peripheral intravenous catheter placed in the upper arm vein for administration of drugs with high irritant potential.

Despite the widespread use of peripheral intravenous catheters, unscheduled catheter failure before completion of treatment occurs frequently. If a large vein is selected, catheter failures may be prevented despite administering a highly irritant drug. In this study, we attempted to use a catheter that can be placed in a large upper arm vein. The new catheter was 88 mm long but had no guidewire to reduce contamination risk. This study aimed to evaluate the safety of the first-in-human trial for the new catheter with the administration of highly irritant drugs. This study was conducted at a university hospital in Tokyo, Japan. Eight Japanese adults were hospitalized adults with planned administration of non-cancer drugs with high irritant potential using a peripheral catheter. A trained nurse catheterized with the new catheter in the upper arm using ultrasonography. The catheterization site was monitored by staff and a research nurse once every 24 hours for up to 7 days. No adverse events or catheter failure occurred and the catheter placement success rate was 100%. In two patients, a temporary occlusion alarm of the infusion pump occurred, possibly due to the flexion of the catheter base. The new peripheral intravenous catheter did not interrupt medical treatments as is common after placement, but safety administered the irritant drugs. However, because this catheter may be easily affected by the contraction of the muscle at the fixation position, the position and method of catheter fixation in the upper arm need to be carefully considered.

[Message from clinical nursing: what to do in basic nursing education for safe medication].

There are a wide variety of drugs used in acute care hospitals. When giving medication, the nurse must first understand the instructions and decide whether the instructions are safe for the patient or can be implemented by the nurse. Then, after the work of preparing the drug, he plays the role of giving the drug by using nursing techniques such as injection, infusion, and tube injection as the final performer. In addition, it plays a role in observing the patient's reaction and promptly responding to any abnormalities. The medication by nurses is a very important, responsible and complex task. In clinical field, we are working to improve knowledge about drugs and simplify work in order to avoid medical accidents caused by medication. However, incidents of medication by nurses have not diminished, and serious medical accidents have not disappeared. In clinical field, we are exploring how to improve the education system and working environment. Appropriate judgment and reliable medication technology are required to safely administer medication. The basis for this is understanding of treatment and knowledge of drugs. What we hope for basic nursing education from the clinical field is to deepen our understanding of the pathophysiology and treatment methods of diseases, the various actions of drugs and their mechanisms, and to practice learning about the dangers hidden in medications performed by nurses.

Changes in the subcutaneous tissue of catheterization site from the precatheterization state to the onset of anticancer drug-induced induration: A case report.

This case showed that anticancer drug administration induces unhealthy subcutaneous tissue (thrombus or edema) without subjective symptoms, abnormal sign by palpation, or inspection, which have an extravasation risk.

Damage to subcutaneous tissue at the catheterization site during chemotherapy: A prospective observational study using ultrasonography.

PURPOSE: Chemotherapy administration can affect subcutaneous tissue at the catheterization site with no macroscopic signs or subjective symptoms. Yet clinical studies about the impact of chemotherapy on tissue at the catheterization site, except for apparent extravasation cases, are limited. This study aimed to investigate subcutaneous tissue changes in nonmacroscopically damaged catheterization sites after chemotherapy administration. METHODS: Participants were people with cancer receiving outpatient chemotherapy. Ultrasonographic images were used to assess the condition of subcutaneous tissues, including the vein, at the catheterization site before catheterization, immediately after chemotherapy, and on the next scheduled treatment day. Data on macroscopic inspection, palpation, and subjective symptoms were also collected and analyzed. RESULTS: Data from 41 participants were analyzed. All had normal subcutaneous tissues before catheterization. After treatment, 16 (39.0%) manifested abnormalities such as subcutaneous edema, vessel wall thickening, and/or thrombosis; there was no extravasation immediately after treatment. On the next treatment day, 15 (36.6.%) showed persistent or new onset of abnormalities, including subcutaneous edema. Eight of the 15 did not exhibit any subjective symptoms or macroscopic or palpation findings. CONCLUSION: After chemotherapy administration via peripheral intravenous catheters, it was found that this damage, which was difficult to detect by the conventional assessment method, persisted. Ultrasonography can provide useful information to avoid reusing damaged sites for chemotherapy administration.

Relationship Between Teams' Leader-Member Exchange Characteristics and Psychological Outcomes for Nurses and Nurse Managers: A Cross-Sectional Study in Japan.

INTRODUCTION: The Leader-Member Exchange (LMX) theory, based on the social exchange theory, relates to positive psychological states among nurses. However, the influence of various LMX qualities coexisting within a team on nurses or nurse managers is still uncleared. OBJECTIVE: This study examines the relationship of nurses and nurse managers' psychological states with the average LMX and LMX dispersion among nurses in their units. METHODS: The study was conducted at two university hospitals in March 2017 using anonymous questionnaires. Nurses completed the LMX-7 scale and the subscales of job satisfaction, achievement, and growth from the Checklist on Commitments Related to Work. Nurse managers completed the subscales of management satisfaction, effectiveness, and extracting extra effort from the Multifactor Leadership Questionnaire. Both nurses and managers completed the Intention to Continue Working scale. The nurses' data were analyzed using a multilevel analysis to clarify associations between nurses' psychological states and LMX, average LMX, and LMX dispersion. Hierarchical multiple regression analysis tested to test the correlations of the psychological states of nurse managers with average LMX and LMX dispersion. RESULTS: Data from 586 nurses and 28 managers were analyzed. The LMX and average LMX of nurses were positively related to positive psychological states. Nurse managers displayed significant associations between high LMX dispersion and good psychological states. When average LMX was low, management effectiveness increased as LMX dispersion increased; when average LMX was high, management effectiveness was almost constant. CONCLUSION: The unit's LMX characteristics appear to be related to the psychological states of both nurses and nurse managers. Increasing the LMX of each nurse may lead to positive psychological states for not only that nurse but all nurses in the unit. When LMX with subordinates is low, increasing LMX with a portion of nurse managers should be a priority to improve their psychological states.

Incidence, risk factors, and assessment of induration by ultrasonography after chemotherapy administration through a peripheral intravenous catheter.

AIMS: Following chemotherapy, induration may occur. This study was conducted to survey induration incidence and risk factors, and investigation for actual condition of induration. METHODS: A cohort study was conducted for survey of incidence and risk factors, and a cross-sectional observation study was conducted to examine actual condition of induration. The sites of chemotherapy administration were recorded, and these were observed on the next treatment day. Clinical nurses judged the presence or absence of induration by palpation. The sites were observed using ultrasonography. To investigate the risk factors associated with the induration, logistic regression analysis was performed using independent variables based on univariate analysis or previous reports. RESULTS: In total, 69 patients were analyzed. The induration incidence was 17.4%, and three abnormal conditions were confirmed: subcutaneous edema, thrombosis, and thickening of the vessel wall. Breast cancer, non-vesicant drug, vein diameter, and fosaprepitant use were included in the logistic regression model. Breast cancer: odds ratio (OR) 9.25; 95 CI 1.91.-44.71; non-vesicant drug: OR 1.37; 95 CI 0.13-14.95; vein diameter: OR 0.40; 95% CI 0.16-0.97; fosaprepitant use: OR 0.16; 95% CI, 0.18-10.32. CONCLUSIONS: The induration incidence was 17.4%. Risk factors for induration following chemotherapy administration were breast cancer and smaller vein diameter. Abnormal cases of subcutaneous tissue were confirmed, including subcutaneous edema, thrombosis, and thickening of the vessel wall. Induration may be prevented by selecting larger diameter vessels using ultrasonography when catheterizing for chemotherapy.

Evaluation of a thermosensitive liquid crystal film for catheterization site assessment immediately following chemotherapy administration: An observational study.

PURPOSE: Extravasation incidence is exceptionally low; however, ulceration or necrosis occurs in severe cases, possibly requiring surgical treatment. Early extravasation signs and symptoms are not always evident on treatment day, and inflammation, which leads to ulceration or necrosis, may appear several days later. Therefore, to minimize damage, identification of high-risk groups is required. This study aims to investigate the relationship between subcutaneous edema which is an early extravasation sign, and skin surface temperature using a thermosensitive liquid crystal film. METHODS: Patients receiving chemotherapy through a peripheral intravenous catheter were recruited. Subcutaneous tissue around the catheterization site was observed for the presence of subcutaneous edema by ultrasonography. During chemotherapy initiation, a thermosensitive liquid crystal film was placed on the catheterization site. Color changes of the film were observed, and each case was classified according to low-temperature distribution patterns. To investigate the factors associated with temperature distribution pattern, logistic regression analysis was performed using clinically selected independent variables. RESULTS: Data from 63 patients were analyzed. No obvious extravasation was observed. Film analysis revealed 34 cases of broadening low-temperature area from the vein and 23 cases of non-broadening low-temperature area from the vein. Subcutaneous edema was observed in 18 patients: 17 with broadening low-temperature area from the vein and 1 with non-broadening low-temperature area from the vein. Subcutaneous edema was positively correlated with broadening low-temperature area from the vein. CONCLUSION: Catheter site skin temperature distribution pattern during chemotherapy was associated with subcutaneous edema which is the early extravasation sign immediately after chemotherapy.

Development of an algorithm using ultrasonography-assisted peripheral intravenous catheter placement for reducing catheter failure.

Up to 50% peripheral intravenous catheters (PIVs) are removed prematurely because of failures. Catheter failure (CF) leads to replacement and is a great concern for patients and medical staff. It is known that visualization of catheters and vessels with ultrasonography (US) during placement prevents CF. However, US is not a common technique for general nurses. In order to standardize US-assisted PIV placement techniques, an algorithm is needed. This study aimed to develop an algorithm using US-assisted PIV placement to reduce CF rate. Furthermore, to evaluate the effectiveness of the algorithm, CF rates were compared before and after intervention. A pretest-posttest study was performed. The intervention was PIV placement by 23 nurses undergoing training sessions for the algorithm. Intention to treat, per protocol analyses were applied. Logistic regression analysis was used for factor analysis. The CF rate in the pre-intervention group 35.2% (19/54) did not significantly differ from post-intervention group 33.6% (48/143) (p = 0.831), yet significantly differ from complete algorithm-use group 8.7% (2/23; p = 0.017). In factor analysis, compliance to the algorithm was significantly correlated with CF (p = 0.032). The compliance rate was low 16.1% (23/143). Algorithm compliance reduced CF by confirming appropriate catheter tip position from the insertion to the securement phase. This algorithm effectively reduced CF, however, the compliance rate was unacceptable. In order to increase the compliance rate, modified algorithm and new visualizing technology is required.

Preventing peripheral intravenous catheter failure by reducing mechanical irritation.

Peripheral intravenous catheter failure is a significant concern in the clinical setting. We investigated the effectiveness of care protocols, including an ultrasonographic "pre-scan" for selecting a large-diameter vein before catheterization, a "post-scan" for confirming the catheter tip position after catheterization with ultrasonography, and the use of a flexible polyurethane catheter to reduce the mechanical irritation that contributes to the incidence of catheter failure. This intervention study was a non-randomized controlled trial to investigate the effectiveness of the abovementioned care protocols, the effects of which were compared to the outcomes in the control group, which received conventional care. For both groups, participants were selected from patients in two wards at the University of Tokyo in Japan between July and November 2017. Inverse probability score-based weighted methods (IPW) using propensity score were used to estimate the effectiveness of care protocols. The primary outcome was catheter failure, which was defined as accidental and unplanned catheter removal. We used Kaplan-Meier survival curves to compare rates of time until catheter failure. We analysed 189 and 233 catheters in the intervention and control groups, respectively. In the control group, 68 catheters (29.2%) were determined to have failed, whereas, in the intervention group, only 21 catheters (11.1%) failed. There was a significant difference between each group regarding the ratio of catheter failure adjusted according to IPW (p = 0.003). The relative risk reduction of the intervention for catheter failure was 0.60 (95% CI: 0.47-0.71). Care protocols, including assessment of vein diameter, vein depth, and catheter tip location using ultrasound examination for reducing mechanical irritation is a promising method to reduce catheter failure incidence.

Continuous monitoring of interface pressure distribution in intensive care patients for pressure ulcer prevention.

AIM: This paper is a report of a study conducted to examine whether continuous interface pressure monitoring of postoperative patients in an intensive care unit is feasible in clinical practice. BACKGROUND: The interface pressure between skin and surfaces is generally evaluated for pressure ulcer prevention. However, the intensity and duration of interface pressure necessary for pressure ulcer development remains unclear because the conventional interface pressure sensors are unsuitable for continuous monitoring in clinical settings. METHODS: A total of 30 postoperative patients in an intensive care unit participated in this study in 2006-2007. A sensor was built into a thermoelastic polymer mattress. The whole-body interface pressure was recorded for up to 48 hours. Pressure ulcer development was observed during the morning bed-bath. For analysis, the intensity and duration of the maximal interface pressure was evaluated. FINDINGS: The mean age of the study group was 62.0 +/- 15.4 years. Two participants developed stage I pressure ulcer and blanchable redness at the sacrum. The longest duration of pressures greater than 100 mmHg were 487.0, 273.5 and 275.7 minutes in the pressure ulcer, blanchable redness and no redness groups respectively. CONCLUSION: Continuous monitoring of the intensity and duration of whole-body interface pressure using the KINOTEX sensor is feasible in intensive care patients.

Ultrasonographic assessment of an induration caused by extravasation of a nonvesicant anticancer drug: A case report.

RATIONALE: Induration may occur after an anticancer drug extravasation in patients who recurrently receive chemotherapy because of reduced choice of an appropriate vein for inserting a peripheral intravenous catheter, resulting in catheter placement difficulty. Although induration affects treatment, its size, shape, or hardness remains unclear in the conventional observation method using palpation and inspection. Here, we report our observation results in using ultrasonography to assess the induration that occurred after an anticancer drug extravasation as a new assessment method. PATIENT CONCERNS: A 58-year-old woman with cervical cancer who complained of pain during the administration of a nonvesicant anticancer drug via a peripheral intravenous catheter. The medical staff's examination showed a swollen site; therefore, the catheter was replaced. DIAGNOSIS: Induration occurred on the site after an extravasation. Over 6 months later, pigmentation and induration, which can easily be confirmed through palpation, persisted. INTERVENTIONS: The subcutaneous tissue in the induration site was observed using ultrasonography (B-mode and elastography). OUTCOMES: The subcutaneous tissue might have degenerated the tissues surrounding the vein, making it thinner. Moreover, the hardness of the subcutaneous tissue was approximately 7 times than that of the surrounding tissues. LESSONS: Induration that affects the vein form and its surrounding tissues should be prevented, and ultrasonography is an effective method to objectively observe the site where extravasation occurred.

Characteristics of subcutaneous tissues at the site of insertion of peripheral infusion in patients undergoing paclitaxel and carboplatin chemotherapy.

Paclitaxel, a taxane, is frequently administered intravenously as an anticancer agent. When a peripheral intravenous catheter is used for paclitaxel infusion, clinical nurses often observe signs such as slight swelling at the catheter placement site, lack of blood return, and difficulty in continuing the infusion. However, the cause(s) of such phenomena at the puncture site has not yet been elucidated. The aim of this study was to obtain ultrasonography images of subcutaneous tissues and veins of patients undergoing paclitaxel and carboplatin chemotherapy and compare ultrasonography images taken immediately before catheter removal with those of patients receiving other types of taxanes. We studied 24 patients receiving chemotherapy, including seven receiving paclitaxel and carboplatin chemotherapy, through a peripheral intravenous catheter in a chemotherapy unit for outpatients of a university hospital in Japan. Ultrasonography images of venipuncture sites were obtained before catheter insertion and immediately before catheter removal. We observed subcutaneous edema in the absence of visible manifestations at the puncture sites of all patients undergoing paclitaxel and carboplatin chemotherapy, but not in any patients receiving other types of taxanes. When vesicant agents and vehicles have caused subclinical subcutaneous edema, clinical nurses may detect early slight extravasation by using ultrasonography.

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.

Removal of Peripheral Intravenous Catheters Due to Catheter Failures Among Adult Patients.

This prospective observational study was designed to clarify the rate of peripheral intravenous catheter, especially short peripheral catheter, failures among adult patients in medical and surgical wards. The study was conducted during a 2-month period at a university hospital in Tokyo, Japan. A total of 5316 catheters from 2442 patients were studied. The rate of catheter removal as a result of catheter failure was 18.8%. The reasons for removal in catheter failures were infiltration (41.3%) and pain (19.3%). Pain was a major reason for catheter failure and removal. For this reason, observing changes under the skin before signs and symptoms appear might help prevent catheter failures.

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-Whitney's U test and Fisher's 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.

Development of an Automatic Puncturing and Sampling System for a Self-Monitoring Blood Glucose Device.

BACKGROUND: Performing self-monitoring of blood glucose (SMBG) is a clinical challenge for elderly people with low dexterity. An all-in-one-type SMBG device that can simply and easily puncture and monitor would be useful for them. We developed an automatic skin-puncturing and blood-sampling (APS) system for introducing of an all-in-one-type SMBG device. The aims of this study were to determine if the developed APS system, which has automatic puncturing, squeezing, and application functions, could provide sufficient blood sample volumes for SMBG and to determine the factors associated with failure in the use of the system by adult volunteers. METHODS: We investigated the success rate of obtaining a 0.8-µL sample volume using the APS system and determined the factors associated with failure in 140 adult volunteers. The participant characteristics, induration of puncturing sites, and states of finger grip conditions were evaluated as factors of a puncturing failure. The participant characteristics, skin hydration, states of finger grip, skin elasticity of the finger pad, and blood flow were evaluated as factors of a squeezing failure. RESULTS: The success rate was 61.9%. Puncturing failure was 21.6%, and squeezing failure was 16.5%. Automatic puncturing factors associated with failure were male sex, larger finger diameter, and thicker finger pad. The only squeezing failure factor was lower peripheral skin temperature. CONCLUSIONS: Improvement of the finger station groove shape to prevent ischemia and the squeezing angle would be useful developments of the all-in-one-type SMBG device for elderly people with decreased dexterity.

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.

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.