Insertion Site Dilemma: Rethinking Radial Arterial Catheter Placement for Device Resilience.

The study by Marie et al (2023) discusses their outcomes regarding the distance of radial arterial catheters from the radiocarpal joint and its association to device failure, although authors found no significant difference in failure rates between catheters inserted proximally or distally to the radiocarpal joint. However, other recent studies have reported that catheters inserted more distally are more likely to fail, with rates high as 25%. Factors that contribute to failure include poor site selection, infection, device occlusion, or dislodgement. With reliance on accurate hemodynamics from arterial catheters, providers should be aware of the risks and take steps to minimize them, as catheter failure is more than just associated infection, the inability to aspirate blood or a useable arterial waveform. Optimal insertion location, use of ultrasound-guided techniques, appropriate securement, and close monitoring of the catheter, along with accurate reporting of failure reasons, will help clarify future research outcomes.

Safe Insertion of Arterial Catheters (SIA): An ultrasound-guided protocol to minimize complications for arterial cannulation.

Direct puncture and cannulation of peripheral arteries is frequently performed in critical care and in emergency settings, mainly for hemodynamic monitoring and blood sampling. While there is abundant literature on peripheral arterial cannulation in children and adults, there is still scope for clinical improvements which may impact on patient safety. Although the radial artery is the most frequently utilized access site today, due to its superficial proximity, ease of access, and low risk of adverse events, other sites are sometimes chosen. The authors propose the Safe Insertion of Arterial Catheters (SIA) protocol, an ultrasound-guided insertion bundle applying a systematic approach to arterial cannulation, with a focus on improving insertion practices, reducing procedural complications, increasing the patient safety profile, and improving device performance.

Clotted blood samples in the neonatal intensive care unit: A retrospective, observational study to evaluate interventions to reduce blood sample clotting.

BACKGROUND: Blood draws for laboratory investigations are essential for patient management in neonatal intensive care units (NICU). When blood samples clot before analysis, they are rejected, which delays treatment decisions and necessitates repeated sampling. AIMS: To decrease the incidence of rejected blood samples taken for laboratory investigation as a result of clotted sample. STUDY DESIGN: This retrospective observational study used routine data on blood draws from preterm infants collected between January 2017 and June 2019 in a 112-cot NICU in Qatar. Quality improvement interventions to reduce the rate of clotted blood samples included: awareness raising and safe sampling workshops with NICU staff, involvement of the neonatal vascular access team, development of a complete blood count (CBC) sample collection pathway, review of sample collection equipment, introducing the Tenderfoot® heel lance, establishment of benchmarks and provision of dedicated blood extraction equipment. RESULTS: First attempt blood draw occurred in 10 706 cases, representing a 96.2% success rate. In 427 (3.8%) cases, the samples were clotted requiring repeat collection. The overall rate of clotted specimens decreased from 4.8% in 2017 and 2018 to 2.4% in 2019, with odds ratios of 1.42 (95% confidence interval [CI] 1.13-1.78, p = .002), 1.46 (95% CI 1.17-1.81, p < .001) and 0.49 (95% CI 0.39-0.63, p < .001), respectively. The majority (87%-95%) of blood samples were by venepuncture using an intravenous (IV) catheter or the NeoSafe™ blood sampling device. Heel prick sampling was the second (2%-9%) most common method. Clotted samples were most frequently associated with needle use, 228 of 427 (53%), and IV cannula, 162 of 427 (38%), with odds ratios of 4.14 (95% CI 3.34-5.13, p < .001) and 3.11 (95% CI 2.51-3.86, p < .001), respectively. CONCLUSIONS: Our interventions over 3 years were associated with reduced rates of sample rejection due to clotting, and this led to improved patient experience through fewer repeated samplings. RELEVANCE TO CLINICAL PRACTICE: The insights gained from this project can help to improve patient care. Interventions that reduce the rate of blood sample rejection by clinical laboratories can lead to economic savings, timelier diagnostic and treatment decisions, and contribute to an improved quality care experience for all critical care patients, irrespective of age, by reducing the need for repeated phlebotomy and the risk of related complications.

Octyl-butyl-cyanoacrylate glue for securement of peripheral intravenous catheters: A retrospective, observational study in the neonatal population.

BACKGROUND: Evidence-based insertion and maintenance strategies for neonatal vascular access devices (VAD) exist to reduce the causes of VAD failure and complications in neonates. Peripheral intravenous catheter failure and complications including, infiltration, extravasation, phlebitis, dislodgement with/without removal, and infection are majorly influenced by catheter securement methods. METHODS: A retrospective, observational study using routinely collected data on intravenous device use in a large neonatal intensive care unit in Qatar. A 6-month historical cohort was compared with a 6-month cohort after the introduction of an octyl-butyl-cyanoacrylate glue (CG). In the historical cohort, the catheter was secured using a semi-permeable transparent membrane dressing while in the CG cohort, CG was applied at the insertion site on initial insertion and after any dressing change. This was the only variable intervention between both groups. RESULTS: A total of 8330 peripheral catheters were inserted. All catheters were inserted and monitored by members of the NeoVAT team. 4457 (53.5%) were secured with just a semi-permeable transparent dressing and 3873 (46.5%) secured a semi-permeable transparent dressing with the addition of CG. The odds ratio for premature failure after securement with CG was 0.59 (0.54-0.65) when compared to the catheters secured with a semi-permeable transparent dressing, which was statistically significant (p < 0.001). The correlation between the occurrence of a complication and the use of CG for device securement was significant (p < 0.001). CONCLUSIONS: The risk of developing device-related phlebitis and premature device removal, increased significantly if CG was not used for adjunct catheter securement. In parallel with the currently published literature, this study's findings support the use of CG for vascular device securement. When device securement and stabilization concerns are most pertinent CG is a safe and effective adjunct to reducing therapy failures in the neonatal patient population.

The SIF protocol: A seven-step strategy to minimize complications potentially related to the insertion of femorally inserted central catheters.

The insertion of central venous catheters through the femoral veins is not uncommon and is potentially associated with the risk of immediate puncture-related complications and severe late complications as infection and thrombosis. As for other central venous access devices, the use of a standardized protocol of insertion and the correct application of evidence-based strategies are beneficial in reducing the risk of complications. We proposed a standardized protocol (S.I.F.: Safe Insertion of Femorally Inserted Central Catheters) consisting of seven strategies that should be part of vascular cannulation and should be adopted during the insertion of femoral venous catheters, aiming to minimize immediate, early and late insertion-related complications. These strategies include: preprocedural evaluation of the patient history and of the veins, appropriate aseptic technique, ultrasound guided puncture and cannulation of the vein, intra-procedural assessment of the tip position, adequate protection of the exit site, proper securement of the catheter, and appropriate coverage of the exit site.

Performance of peripheral catheters inserted with ultrasound guidance versus landmark technique after a simulation-based mastery learning intervention.

PROBLEM: Ultrasound-guided peripheral intravenous catheter (USGPIV) insertion is an effective method to gain vascular access in patients with difficult intravenous access (DIVA). While USGPIV success rates are reported to be high, some studies have reported a concerning incidence of USGPIV premature failures. AIMS: The purpose of this study was to compare differences in USGPIV and landmark peripheral intravenous catheter (PIV) utilization and failure following a hospital-wide USGPIV training program for nurses. METHODS: The authors performed a retrospective, electronic medical record review of all USGPIVs and PIVs inserted at a tertiary, urban, academic medical center from September 1, 2018, through September 30, 2019. The primary outcome was differences between USGPIV and PIV time to failure. RESULTS: A total of 43,470 short peripheral intravenous catheters (PIVCs) were inserted in 23,713 patients. Of these, 7972 (16.8%) were USGPIV. At 30 days of follow-up, for PIVCs with an indication for removal documented, USGPIVs had higher Kaplan-Meier survival probabilities than PIVs (p < 0.001). CONCLUSIONS: The use of simulation-based mastery associated with USGPIVs, demonstrated lower failure rates than standard PIVs after 2 days and USGPIVs exhibited improved survival rates in patients with DIVA. These findings suggest that rigorous simulation-based insertion training demonstrates improved USGPIV survival when compared to traditional PIVCs. SBML is an extremely useful tool to ensure appropriately trained clinicians acquire the necessary knowledge and skillset to improve USGPIV outcomes.

Impact of intravenous access site on attenuation for thoracic computed tomographic angiography: A time-matched, nested, case-control study.

BACKGROUND: The objective of this study was to evaluate whether the choice of intravenous access (IVA) site affects aortic attenuation during thoracic computed tomographic angiography (T-CTA) and any associated risks with intravenous device placement. METHODS: All T-CTA exams performed between 1/1/2013 and 8/14/2015 were retrospectively reviewed to identify those performed with contrast media injection via alternative (i.e. non-antecubital) IVA (n = 1769). Using time matching, antecubital IVA exams (n = 1769) were selected as controls. For each exam, attenuation was measured in the ascending aorta. Patient and technical data was subsequently collected from all 3538 patients included in this study. Multiple linear regression was used to determine if IVA site affected attenuation. Lastly, data related to extravasations for the entire T-CTA cohort were collected and compared. RESULTS: Hand/wrist, arm, and central venous access device IVA were all equivalent to antecubital IVA in terms of attenuation (P = 0.579, P = 0.599, and P = 0.522 respectively). Forearm and intraosseous IVA had significantly higher attenuation (P = 0.010 and P = 0.002, respectively) than antecubital IVA. Right-sided IVA was associated with a small attenuation increase of 11 Hounsfield Units (P < 0.001) compared to left-sided IVA. In terms of extravasation, antecubital IVA was equivalent to hand/wrist, forearm, and upper arm IVA (P = 0.778, P = 0.060, and P = 0.090 respectively). CONCLUSIONS: Satisfactory aortic attenuation achieved with non-antecubital IVA is equivalent to attenuation achieved with antecubital IVA for T-CTA imaging. The risk of contrast media extravasation in peripheral IVA devices was relatively low, however, appropriate IVA site selection should be considered an important factor for successful administration of contrast media for future imaging studies. This prevents undue harm to patients through preventable device failures when using a peripheral IV device in areas of high flexion/range of movements undergoing pressure injection for contrast media.

The SIC protocol: A seven-step strategy to minimize complications potentially related to the insertion of centrally inserted central catheters.

Insertion of central venous catheters in the cervico-thoracic area is potentially associated with the risk of immediate/early untoward events, some of them negligible (repeated punctures), some relevant (accidental arterial puncture), and some severe (pneumothorax). Furthermore, different strategies adopted during insertion may reduce or increase the incidence of late catheter-related complications (infection, venous thrombosis, dislodgment). This paper describes a standardized protocol (S.I.C.: Safe Insertion of Centrally Inserted Central Catheters) for the systematic application of seven basic beneficial strategies to be adopted during insertion of central venous catheters in the cervico-thoracic region, aiming to minimize immediate, early, or late insertion-related complications. These strategies include: preprocedural evaluation, appropriate aseptic technique, ultrasound guided insertion, intra-procedural assessment of the tip position, adequate protection of the exit site, proper securement of the catheter, and adequate coverage of the exit site.

The ABBA project (Assess Better Before Access): A retrospective cohort study of neonatal intravascular device outcomes.

Background: Venous access devices (VADs) play a vital role within the neonatal intensive care unit. However, there are significant risks associated with the use of VADs, with complications such as infection, thrombosis, device occlusion, and infiltration/extravasation frequently contributing to device-related failures and increasing the risk of significant patient harm or injury. This study aimed to explore the relationships between risk factors and different venous access device complications in the neonatal setting, and then use that evidence to develop an algorithm based on observational data. Methods: This is a retrospective, single-center cohort study that was conducted in a large 112-bed neonatal intensive care unit in Qatar. We examined venous access device data from January 2016 to December 2018 for all term and preterm neonates. Descriptive statistics were used to summarize the outcomes, which included a mean and its standard deviation or median and an interquartile range for continuous variables regarding normal distribution, and absolute numbers with percentages for discrete variables. Results: The authors recorded a total of 23,858 VADs inserted during the study period. Of these, 21,313 (89%) were peripheral intravenous catheters, 689 (3%) were extended dwell-peripheral intravenous catheters, 1,335 (6%) were epicutaneo-caval catheters, and 521 (2%) were umbilical venous catheters. In total, 51,179 catheter days were registered, with 2.17 catheter days reported per patient. Peripheral device dwell times were significantly shorter when compared with central venous catheter devices (P < 0.001), with mean dwell times of 22 days ± 23 h and 236 days ± 183 h, respectively. After insertion, a complication occurred in 11,177 (51%) of peripheral VADs and 221 (12%) of central VADs. The type of device inserted [P < 0.001, hazard ratio (HR) = 0.52, 95% confidence interval (CI): 0.50-0.54], reason/indication for intravenous therapy (P < 0.001, HR = 0.85, 95% CI: 0.82-0.87), and the side of insertion of the device (P < 0.001, HR = 1.25, 95% CI: 1.24-1.27) had a significant relationship with outcomes. Conclusions: Four subgroups of VADs were identified (peripheral intravenous catheters, extended dwell-peripheral intravenous devices, epicutaneo-caval catheters, and umbilical venous catheters) with outcome-related differences. Central venous access devices (epicutaneo-caval catheters and umbilical venous catheters) had lower complications compared with peripheral VADs. Proper venous access device selection, early insertion, and early removal approaches remain crucial to preventing venous access device complications. Peripheral intravenous devices should be used carefully and closely watched for early detection of complications.

10 best practice tips with radial arterial catheterization.

Radial arterial catheters (RAC) are used extensively across critical care settings (Anesthesia, Intensive Care, Emergency Medicine) for continuous hemodynamic monitoring, allowing for immediate adjustments in vasopressor therapies and blood collection. Radial catheter failures are an ongoing significant issue for critical care clinicians with reported incidences at almost 25%. Common complications include loss of function, lack of blood return, poor quality waveforms and dislodgement, posing potential patient risks, and sudden loss of intra-arterial monitoring frequently requires prompt replacement. Contemporary research and technological improvements have highlighted several concepts to enhance the approach of RAC insertion and management while reducing immediate and late complications. The authors have prioritized the following 10 "best practice" aspects that may improve overall device function and reliability.

The SIP protocol update: Eight strategies, incorporating Rapid Peripheral Vein Assessment (RaPeVA), to minimize complications associated with peripherally inserted central catheter insertion.

Insertion of Peripherally Inserted Central Catheters (PICCs) is potentially associated with the risk of immediate/early adverse events, some of them minimal (repeated punctures) and some relevant (accidental arterial puncture or nerve-related injury). Several strategies adopted during the insertion process may minimize the risk of such events, including late complication risks such as infection, venous thrombosis, or catheter dislodgment and/or malposition. This paper describes an update version of the SIP protocol (Safe Insertion of PICCs), an insertion bundle which includes eight effective strategies that aims to minimize immediate, early, or late insertion-associated complications. These strategies include: preprocedural ultrasound assessment utilizing the RaPeVA (Rapid Peripheral Venous Assessment) protocol; appropriate skin antiseptic technique; choice of appropriate vein, adoption of the Zone Insertion Method™; clear identification of the median nerve and brachial artery; ultrasound-guided puncture; ultrasound-guided tip navigation; intra-procedural assessment of tip location; correct securement of the catheter, and appropriate protection of the exit site. This updated version of the SIP protocol includes several novelties based on the most recent evidence-based scientific literature on PICC insertion, such as the clinical relevance of the tunneling technique, the use of ultrasound for intra-procedural tip navigation and tip location, and the new technologies for the protection of the exit site (cyanoacrylate glue) and for the securement of the catheter (subcutaneous anchorage).

Preventing radial arterial catheter failure in critical care - Factoring updated clinical strategies and techniques.

Radial artery catheterization is a frequently performed procedure for critically ill patients. The correct function of arterial catheters is essential to provide accurate and continuous hemodynamic monitoring, facilitating intermittent blood sampling and helping to optimize the workload for critical care nurses and physicians. However, they are not without their own problems. This narrative practice review discusses several clinical aspects that are not frequently considered but may contribute to enhanced catheter functionality, less device-related failure and more acceptable dwell times. Ultrasound has demonstrated unequivocal efficacies and safety with the procedure, improving first attempt success rates with children, the obese or patients with unstable clinical vital signs and shock. Moreover, anatomic variations of the radial artery are not rare, and ultrasound-guided catheterization reduces the incidence of insertion-related complications such as hematoma, posterior wall puncture, intimal dissection, and radial nerve injury. Ultrasound guidance offers several immediate benefits by enhancing the most appropriate insertion techniques, allows for the correct catheter to vessel ratio measurements to be performed and reduces the angle of insertion, which may affect catheter failure due to inappropriate catheter length. A deeper and more proximal cannulation site at least 4 cm from wrist joint, avoiding the area of wrist flexion, reduces mechanical complications related to patient movements and may improve catheter functionality and dwell along with a better area for stabilization and securement.

Evaluation of a diluted lipid emulsion solution as a lubricant for improved peripherally inserted central catheter guidewire removal in a neonatal population.

BACKGROUND: Medical management of neonates is often established upon safe and reliable vascular access, frequently utilized to provide physiological monitoring, parenteral and supportive treatments, and diagnostic and/or procedural purposes. For this, peripherally inserted central catheters (PICCs) are often used to provide safe vascular access and infusion-related therapies in the neonatal intensive care (NICU) setting. PURPOSE: Difficult PICC guidewire removal is understood to cause catheter damage, causing luminal rupture or possible breakage of the catheter or guidewire itself. The aim of this study was to assess and compare the incidence of therapy failures with use of a preflush fluid using normal saline (NSS) versus a diluted lipid solution (DLS) prior to device insertion, to assist with guidewire removal and prevent unnecessary catheter damage. METHOD AND SETTING: A retrospective, observational study was performed in the Neonatal Intensive Care Unit (NICU) of the Women's Wellness and Research Centre, Hamad Medical Corporation, Qatar. This single site study included 507 neonates who required intravenous therapy administered via a PICC during the study period. RESULTS: Results demonstrated the use of a diluted lipid solution preflush (DLS) resulted in significantly lesser failures, when compared with the control group (NSS). This highlights a clinical significance after adjusting for day of insertion, gestational age, birth weight and catheter type. CONCLUSION: DLS preflush demonstrated a benefit over the use of a NSS preflush to enhance PICC guidewire removal in neonatal patients in the NICU. The risk for development of maintenance-related complications leading to premature device removal decreased significantly if the DLS preflush was used. During the study period, no complications related to the use of a lipid preflush solution were identified. IMPLICATIONS FOR PRACTICE AND RESEARCH: This may be the first study published investigating and supporting guidewire removal enhancement by using a diluted lipid/saline preflush solution. When the requirement for vascular access is most pertinent in the neonate, using a diluted lipid preflush may provide an effective method to assist in guidewire removal to prevent malposition and vascular device complications in the neonatal population.

Cyanoacrylate Securement in Neonatal PICC Use: A 4-Year Observational Study.

BACKGROUND: Within every neonatal clinical setting, vascular access devices are considered essential for administration of fluids, nutrition, and medications. However, use of vascular access devices is not without danger of failure. Catheter securement adhesives are being evaluated among adult populations, but to date, studies in neonatal settings are scant. PURPOSE: This research describes the prevalence of peripherally inserted central catheter failure related to catheter securement before and after the introduction of tissue adhesive for catheter securement. The identified modifiable risks might be used to evaluate efficacy, to innovate neonatal practice and support future policy developments. METHOD AND SETTING: This was a retrospective observational analysis of routinely collected anonymized intravenous therapy-related data. The study was carried out at the tertiary neonatal intensive care unit (112 beds) of the Women's Wellness and Research Center of Hamad Medical Corporation, Doha, Qatar. RESULTS: The results showed that the use of an approved medical grade adhesive for catheter securement resulted in significantly less therapy failures, compared with the control group. This remains significant after adjusting for day of insertion, gestational age, birth weight, and catheter type. IMPLICATIONS FOR PRACTICE AND RESEARCH: In parallel with currently published international literature, this study's findings support catheter securement with an octyl-based tissue adhesive in use with central venous catheters. When device stabilization is most pertinent, securement with tissue adhesive is a safe and effective method for long-term vascular access among the neonatal population.

Clinical experience with a chlorhexidine-coated PICC: A prospective, multicenter, observational study.

INTRODUCTION: This study evaluated a chlorhexidine-coated peripherally inserted central catheter (PICC) and the incidence of associated complications within both inpatient and outpatient populations. METHODS: This IRB-approved, multicenter, prospective observational study was performed at three large teaching hospitals in the US. All adults who required a PICC for ⩾14 days were considered. Patients were monitored throughout entire catheter dwell. Duplex venous ultrasounds were performed before insertion, after 10 to 14 days of dwell time, and upon removal. Data was collected from the hospital, outpatient clinic, and patient PICC diary records. RESULTS: A total of 103 patients, 56% male, with mean BMI 29 ± 8.8, were enrolled. The majority (79%) of patients were from high-risk groups-cancer, infectious diseases, transplant, and trauma. Primary treatment indications were antibiotics (66.99%) and chemotherapy (25.24%). Double lumen PICCs (59.2%) were favored clinically, as was basilic vein placement (71.84%). Mean catheter dwell was 47.01 ± 25.82 days. Three (3, 2.9%) central line-associated bloodstream infections (CLABSI) were reported. Four patients (4.6%) reported symptomatic catheter-related thrombosis (CRT), confirmed with ultrasound. Three patients (3.4%) had ultrasound-confirmed fibroblastic sleeve (FS). Eight patients (9.2%) who entered the study with pre-existing superficial thrombosis, had complete resolution at the time of catheter removal. The incidence of CLABSI was 0.82/1000 days. The combined CRT and FS rate was 6.9%. CONCLUSION: Based upon the observational findings of this study, chlorhexidine-coated PICC technology may be considered for use in patient populations who are at moderate to high-risk for catheter-related complications in both inpatient and outpatient settings.

Arterial insertion method: A new method for systematic evaluation of ultrasound-guided radial arterial catheterization.

INTRODUCTION: Peripheral arterial catheter insertion is a common procedure for critically ill patients requiring frequent blood gas sampling and continuous blood pressure monitoring. There are clear advantages of ultrasound-guided arterial cannulation, which have shown to be more effective in reducing complications, time to successful cannulation, number of attempts, and overall first-time success rates. Evidence suggests that using palpation alone has a first-time success rate of less than 70% yet is still a widely performed technique. A systematic evaluation may be required to reduce variations in arterial catheterization practices. DESIGN: The arterial insertion method is a systematic evaluation to aid in arterial catheter insertion with ultrasound guidance, intended to improve the procedural approach. The process of arterial insertion method ensures appropriate choice of zone selection to optimize catheter longevity and performance in patients requiring arterial access. Moving the insertion site proximally 4 cm from the red zone into the green zone may reduce mechanical complications and preserve catheter performance and dwell time. CONCLUSION: The standardization of ultrasound guidance in arterial catheterization promotes vessel health and patient safety through device and site optimization. The arterial insertion method systematic evaluation may be utilized to reduce variation in practice and promote the use of ultrasound as a standard for the insertion of radial arterial catheters.

Implementing an emergency department vascular access team: A quality review of training, competency, and outcomes.

Peripheral intravenous catheters are frequently used devices in emergency departments. Many patients now present with difficult anatomy and are labeled as difficult intravenous access patients. A common technology to address this challenge is ultrasound. While studies have examined the ability to train emergency staff, few have addressed how this should be done and the outcomes associated with such training. No studies were found with dedicated vascular access specialist teams in emergency departments. An emergency department vascular access specialist team was formed at a hospital in Bangor, Maine, United States to train, validate, and proctor clinicians with ultrasound-guided peripheral intravenous devices. A quality review of this process was compiled and determined that appropriate clinicians with dedicated training and guidance can achieve higher levels of procedural success. Furthermore, evidence substantiates that frequent practice is linked to a higher quality of care and that a significant need for such teams is present. This review examines how a team was implemented and its impact both department- and facility-wide. It is possible that hospitals benefit from the services of vascular access specialists to provide higher quality care. Successful implementation of such specialist teams requires foundational knowledge and skills in vascular access with ongoing quality measures to ensure competency and compliance with evidence-based practices.

Dynamic variation of the axillary veins due to intrathoracic pressure changes: A prospective sonographic study.

INTRODUCTION: The ultrasound-guided axillary vein is becoming a compulsory alternative vessel for central venous catheterization and the anatomical position offers several potential advantages over blind, subclavian vein techniques. OBJECTIVE: To determine the degree of dynamic variation of the axillary vein size measured by ultrasound prior to the induction of general anesthesia and after starting controlled mechanical ventilation. DESIGN: Prospective, observational study. METHODS: One hundred ten patients undergoing elective surgery were enrolled and classified according to sex, age, and body mass index. Two-dimensional cross-sectional vein diameter, area, and mean flow velocity were performed using ultrasound on both the left and right axillary veins of each subject before and after induction of anesthesia. RESULTS: There was statistically significant evidence showing that the axillary vein area increases when patients are mechanically ventilated. When considering venous flow velocity as a primary outcome, velocity decreased after patients moved from spontaneous to mechanical ventilation (coefficient = -0.267), but this relationship failed to achieve statistical significance (t = -1.355, p = 0.179). CONCLUSIONS: Anatomical variations in depth and diameter as well as the collapsibility due to intrathoracic pressures changes represent common challenges that face clinicians during central venous catheterization of the axillary vein. A noteworthy increase in vessel size as patients transition from spontaneous to mechanical ventilation may theoretically improve first-pass cannulation success with practitioners skilled in both ultrasound and procedure. As a result, placing a centrally inserted central catheter after the induction of anesthesia may be beneficial.