Peripheral intravenous catheters (PIVCs) are among the most frequently utilized vascular access devices in hospitalized patients. They play a critical role in the administration of intravenous fluids, medications, blood products, and nutritional supplementation, especially in acute care settings [1]. Despite their widespread use and clinical utility, PIVCs are associated with several complications, of which catheter-related thrombophlebitis is the most common and clinically significant [2,3].

Thrombophlebitis, defined as inflammation of a vein with associated thrombus formation, contributes to patient discomfort, interruption of intravenous therapy, increased infection risk, and prolonged hospitalization [3]. Global incidence rates of PIVC-related thrombophlebitis vary widely, ranging from 1.3% to 70%, influenced by factors such as catheter dwell time, site of insertion, catheter material, and adherence to aseptic protocols [4]. In the Indian setting, the reported incidence ranges from 25% to nearly 60%, with variation attributed to differences in institutional practices, healthcare infrastructure, and infection control measures [5].

The etiology of PIVC-related thrombophlebitis is multifactorial. Mechanical factors such as repeated cannulation or the use of large-gauge catheters can damage the endothelium, initiating an inflammatory response. Chemical factors, including infusates with extreme pH or osmolarity, exacerbate vascular irritation. Infections, particularly those caused by skin flora contaminating the catheter, also play a pivotal role, with bacterial biofilms facilitating persistence and resistance [6].

Several host and procedural risk factors have been implicated in the development of thrombophlebitis. Advanced age, female sex, diabetes mellitus, immunosuppression, and comorbidities such as chronic kidney disease increase the vulnerability of patients [7]. Procedural variables such as the skill of the inserter, catheter material and gauge, site of insertion, frequency of catheter manipulation, and aseptic technique adherence significantly influence the risk profile [2,8].

Microbiologically, gram-positive organisms, especially Staphylococcus aureus and coagulase-negative staphylococci, are the most commonly implicated pathogens, often originating from skin flora. Gram-negative organisms such as Pseudomonas aeruginosa and Klebsiella spp. are increasingly isolated in immunocompromised patients or where infection control is inadequate [9]. The emergence of multidrug-resistant (MDR) organisms, particularly MRSA and ESBL-producing gram-negative bacilli, has further complicated the management of catheter-related infections [10].

Despite a growing body of evidence on PIVC-associated complications, there remain notable gaps in epidemiological data regarding thrombophlebitis in the Indian context, especially with respect to incidence, risk factor profiling, and the bacteriological spectrum. This study was conducted to estimate the incidence of catheter-related thrombophlebitis in patients receiving PIVCs at a tertiary care center.

Study Design and Setting: This study was designed as a cross-sectional observational investigation conducted at the Department of General Medicine, PGIMER & Capital Hospital, Bhubaneswar, Odisha. The study period spanned from May 2023 to December 2024. The primary objective was to assess the incidence of peripheral intravenous catheter (PIVC)-related thrombophlebitis among hospitalized patients.

Study Population: All hospitalized patients aged 14 years and older who underwent peripheral venous catheterization for at least 24 hours were considered eligible. Patient recruitment was carried out consecutively, following informed consent.

Inclusion Criteria:

• Age ≥14 years.
• Hospitalization with requirement of PIVC insertion.
• Minimum duration of catheter placement: 24 hours.
• Informed consent for participation.

Exclusion Criteria:

• Pre-existing thrombophlebitis on admission.
• Use of central venous catheters.
• Known bleeding disorders or ongoing anticoagulant therapy.

Sample Size Estimation: Assuming a baseline incidence of 10% for PIVC-related thrombophlebitis, and using a confidence level of 95% with a precision of ±1.5%, the calculated minimum sample size was 1538. After accounting for a 10% anticipated dropout, the adjusted target was 1709. However, due to logistical constraints, 1340 patients were ultimately enrolled. A post hoc power analysis confirmed this number to be statistically sufficient to detect moderate effect sizes.

Data Collection: Data were systematically gathered using a structured and validated case record form. All enrolled patients were monitored daily for signs of phlebitis until catheter removal. The Visual Infusion Phlebitis (VIP) scoring system was used to assess inflammation at the insertion site, with a score ≥2 considered diagnostic of clinically significant thrombophlebitis.

Microbiological Evaluation: In patients developing thrombophlebitis (VIP score ≥2), the catheter was removed aseptically. The distal 2–3 cm of the catheter tip was aseptically excised and transported to the microbiology laboratory in sterile containers. The roll-plate technique, as described by Maki et al., was used for semi-quantitative culture on blood agar. Colonization was defined by the growth of ≥15 colony-forming units (CFU).

Identification and Susceptibility Testing: Isolates were identified using conventional biochemical methods and automated systems where available. Antimicrobial susceptibility was determined using the Kirby-Bauer disc diffusion technique on Mueller-Hinton agar, following CLSI guidelines. Detection of multidrug-resistant organisms (MDROs) included:

• MRSA: Confirmed by cefoxitin disc diffusion.
• ESBL producers: Detected via combined disc method.
• Carbapenem resistance: Evaluated using Modified Hodge Test (MHT) or Carba NP test.

Outcome Measures:

Primary Outcome- Incidence of thrombophlebitis among PIVC recipients, diagnosed clinically (VIP score ≥2).

Secondary Outcome- Identification of independent risk factors (demographic, catheter gauge, usage of gloves).

Statistical Analysis: Data were entered into Microsoft Excel and analyzed using SPSS. Descriptive statistics were applied to summarize the study population. Categorical variables were compared using the Chi-square or Fisher’s exact test. Continuous data were analyzed using t-test or Mann–Whitney U test based on distribution. Logistic regression was employed for multivariate analysis of risk factors. A p-value of <0.05 was considered statistically significant.

The overall incidence of catheter-related thrombophlebitis, defined as a Visual Infusion Phlebitis (VIP) score of 2 or higher, was 22.0% (Figure 1).

Figure 1: Incidence if PIVC related thrombophlebitis (%)

Age-wise stratification revealed a statistically significant association between age group and thrombophlebitis incidence (p = 0.011). The highest prevalence was observed among patients aged 40–59 years, while those aged 14–39 years had the lowest (Table 1).

Table 1: Age-wise Prevalence of Peripheral Intravenous Catheter-related Thrombophlebitis

Analysis by gender demonstrated that female patients had a higher rate of thrombophlebitis compared to males. Although the culture positivity among those with thrombophlebitis was comparable across genders, a larger proportion of thrombophlebitis cases occurred in females than males, indicating a possible sex-related predisposition (Table 2).

Table 2: Gender-wise Distribution of Thrombophlebitis and Culture Positivity

Regarding the severity of thrombophlebitis, as classified by the VIP score, the majority of affected patients presented with Grade 2 phlebitis. Progressively fewer patients were observed with higher-grade inflammation, suggesting that most cases were mild to moderate in severity at detection (Table 3).

Table 3: Distribution of VIP Scores and Definition-Based Thrombophlebitis

When evaluating the size of the intravenous catheter used, smaller gauge catheters (22G and 20G) were the most frequently employed, together accounting for over 70% of the insertions. The larger bore catheters (14G, 16G, 18G) were used sparingly (Table 4). This distribution reflects a preference for smaller gauges, likely aimed at minimizing mechanical trauma and associated complications.

Table 4: Distribution of Catheter Gauge among Study Participants

An important procedural parameter evaluated was the use of gloves during cannulation. Notably, in more than half of the cases (52.1%), gloves were not used during catheter insertion (Table 5). This finding raises concern regarding adherence to aseptic precautions and its potential impact on infection-related complications, including thrombophlebitis.

Table 5: Usage of Gloves during Intravenous Catheter Insertion

This study assessed the incidence, associated risk factors, and bacteriological profile of peripheral intravenous catheter (PIVC)-related thrombophlebitis in a tertiary care setting. The overall incidence of thrombophlebitis observed was 22.0%, which aligns with previously reported data from Indian healthcare institutions, where rates have ranged between 25% and 59% [5]. The moderate incidence noted in our study may reflect institutional variations in cannulation practices, catheter dwell times, and infection control protocols.

Age-stratified analysis revealed a statistically significant variation, with the highest prevalence found among patients aged 40–59 years. While thrombophlebitis has been reported to occur more frequently in younger adults in some studies, others have noted increased vulnerability among elderly individuals due to vascular fragility and comorbidities [11,12]. This underscores the multifactorial nature of risk influenced by both host and procedural factors. The higher rate observed in middle-aged adults in our cohort may be attributed to the higher number of intravenous medications administered in this group.

Female sex was significantly associated with a higher incidence of thrombophlebitis in this study. This finding supports prior reports suggesting that hormonal differences, vein diameter, and tissue sensitivity may influence the risk of catheter-related complications [12]. Interestingly, culture positivity among thrombophlebitis cases did not differ markedly between sexes, implying that microbial burden is independent of gender and is likely more closely related to procedural sterility and catheter care.

Most thrombophlebitis cases in this study were classified as Grade 2 by the Visual Infusion Phlebitis (VIP) score, indicating early-stage inflammation. This observation suggests effective routine monitoring and early identification of phlebitis in our setting, thereby preventing progression to more severe grades. Previous literature emphasizes the value of standardized phlebitis assessment tools in facilitating timely intervention and reducing complications [1].

Catheter gauge was another important determinant. The study population predominantly received 20G and 22G catheters, which are associated with a lower risk of mechanical irritation compared to larger bore catheters [13]. Despite this preference, the incidence of thrombophlebitis remained notable, suggesting that other variables, such as dwell time, medication properties, or insertion site, may have contributed.

Aseptic technique is a cornerstone of preventing catheter-associated infections and thrombophlebitis. Alarmingly, gloves were not used in over half of the cannulation procedures in our study. Similar findings have been reported in other resource-limited settings, where compliance with infection prevention protocols remains suboptimal [14]. Lack of glove use potentially increases the risk of microbial contamination at the insertion site and subsequent catheter colonization, reinforcing the need for rigorous staff training and protocol enforcement.

The bacteriological spectrum of thrombophlebitis in the broader literature is dominated by gram-positive organisms, particularly Staphylococcus aureus and coagulase-negative staphylococci, both known for their biofilm-forming capacity [10]. Although the detailed microbial results of this study are not presented here, previous institutional data and published studies in similar settings have confirmed the predominance of these organisms, often complicated by antimicrobial resistance [14].

Overall, the findings of this study emphasize the continued burden of PIVC-related thrombophlebitis in hospitalized patients and highlight modifiable risk factors, including catheter size, aseptic technique, and regular site monitoring. Addressing these through evidence-based guidelines and staff education could significantly reduce incidence and improve patient outcomes.

Peripheral intravenous catheter-related thrombophlebitis remains a common yet preventable complication in hospitalized patients. This study identified a significant incidence rate, with middle-aged individuals and females being more frequently affected. The predominant use of smaller gauge catheters did not eliminate the risk, indicating multifactorial causation including poor aseptic practices. Most cases were of mild to moderate severity, emphasizing the importance of early detection through routine monitoring. Strengthening adherence to aseptic protocols and targeted interventions based on identified risk factors can substantially reduce the burden of thrombophlebitis.

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