Effect of individualized anesthesia and analgesia on postoperative pain in patients stratified for pain sensitivity: A study protocol for the PeriOPerative individualization trial randomized controlled trial.

BACKGROUND: Despite advancements in surgical and anesthesia techniques, acute and persistent postoperative pain are still a common challenge. Postoperative pain has direct effects on individual patient care and outcome, as well as putting strain on limited health care resources. Several prediction methods for postoperative pain have been described. One such method is the assessment of pain during peripheral venous cannulation (VCP). It is not known if different approaches to anesthesia and analgesia, depending on the evaluation of risk for postoperative pain, can improve outcome. The aim of this study is to evaluate if individualized anesthesia and analgesia can affect postoperative pain and recovery after surgery, in patients stratified by VCP. METHODS: Adult patients scheduled for laparoscopic surgery undergo pain-sensitivity stratification using VCP on the day of surgery. Patients scoring VCP ≥2.0 on the visual analogue scale (pain-sensitive) are randomized to multimodal anaesthesia and analgesia with opioids or standard of care. Patients scoring VCP ≤1.9 (pain-tolerant) are randomized to opioid-free anaesthesia or standard of care. The primary outcome is acute postoperative pain measured with numeric rating scale in the postoperative care unit. Secondary outcomes include analysis of pain after 24 h, persistent postoperative pain and quality of recovery. DISCUSSION: Individualized perioperative pain management has the potential to improve patient care. This study will examine the impact of different anesthesia and analgesia regimes, in patients with differing pain sensitivity, on postoperative pain. TRIAL REGISTRATION: Prospectively posted at ClinicalTrials.gov, identifier NCT04751812.

Evaluation of the Efficacy of a Novel Dermatotomy Device for Central Venous Cannulation.

OBJECTIVE: To test the effectiveness of a novel wire-guided scalpel (Guideblade) to create a precise dermatotomy incision for central venous catheter (CVC) insertion. DESIGN: Prospective, nonrandomized interventional study. SETTING: Stanford University, single-center teaching hospital. PARTICIPANTS: Cardiac and vascular surgical patients (n = 100) with planned CVC insertion for operation. INTERVENTIONS: A wire-guided scalpel was used during CVC insertion. RESULTS: A total of 188 CVCs were performed successfully with a wire-guided scalpel without the need for additional equipment in 100 patients, and 94% of CVCs were accomplished with only a single dermatotomy attempt. "No bleeding" or "minimal bleeding" at the insertion site was observed in 90% of patients 30 minutes after insertion and 80.7% at the conclusion of surgery. CONCLUSION: The wire-guided scalpel was effective in performing dermatotomy for CVC with a 100% success rate and a very high first-attempt rate. The wire-guided scalpel may decrease bleeding at the CVC insertion site.

Comparison of music and vapocoolant spray in reducing the pain of venous cannulation in children age 6-12: a randomized clinical trial.

BACKGROUND: Venous cannulation is among the most stressful and painful experiences of children hospitalization. Children with thalassemia need regular blood transfusion which needs venous access each time. The quality of care and quality of life of children will be improved if appropriate methods are used to reduce pain. This study aimed to compare vapocoolant spray and music in the reduction of pain of Venous cannulation in children with thalassemia. METHODS: The study was a randomized controlled clinical trial with a cross-over design. Thirty-six children with thalassemia from Thalassemia Patients of Pasteur Hospital in Bam from October to December 2020 and were recruited and randomly allocated to two arms. The pain of venous cannulation (no treatment) was measured in the first blood transfusion session as control. In the second and third sessions, two arms received music and vapocoolant spray before the venous cannulation with a cross-over design. The intensity of pain was measured by a Visual Analogue Scale (VAS). The change in pain scores was tested by ANOVA and Tukey post-hoc test between three measurements. RESULTS: During and after the cannulation, the pain was significantly lower in the vapocoolant measurement than in control and music (p < 0.05). There was a significant effect of vapocoolant spray during the procedure F (2, 90) = 25.604, p = 0.001. Also, there was a significant effect of vapocoolant spray after the procedure F (2, 90) = 10.087, p = 0.004). Music did not reduce the pain during cannulation (p = 0.413) and after that (p = 0.807) significantly when compared with control. CONCLUSIONS: Vapocoolant was an effective method of pain reduction in the reduction of venous cannulation pain. Music was not effective in the reduction of venous cannulation pain when we compared it with controls. The pain of venous cannulation is rated as high and it can have negative effects on the children. There is a need to do more research on the methods of pain reduction of venous cannulation. TRIAL REGISTRATION: The trial is registered: IRCT20111019007844N13, 13/03/2020. Available at: https://en.irct.ir/trial/42904 .

Absorbable sutures for cardiopulmonary bypass purse strings in pediatric heart surgery.

BACKGROUND: Absorbable sutures, commonly used in general surgery, are not routinely used as purse strings for arterial and venous cannulation for cardiopulmonary bypass in pediatric heart surgery. The general concern is absorbable sutures could predispose to immediate postoperative bleeding; this safety concern has been evaluated in this retrospective study. MATERIALS AND METHODS: A single center, retrospective study, was conducted with criteria for inclusion patient <18 years of age, operation on with cardiopulmonary bypass for heart surgery from July 1, 2018 to June 30, 2020, with purse strings for cannulation performed with absorbable sutures. Data collection included demographics at the time of surgery, site of arterial and venous cannulation with absorbable purse strings, bleeding, required reoperation, related hospital mortality, and complications. RESULTS: One hundred and ninety-eight patients, mean ± standard deviation (SD) age of 1597 ± 3021 days, mean ± SD body weight of 15.9 ± 18.8 kg, were operated on using absorbable sutures for purse strings for arterial and venous cannulation: No bleeding was reported, either intraoperative or in the immediate postoperative period, related to the type of sutures used for purse strings for cannulation. No hospital deaths or complications related to the type of sutures were observed. CONCLUSIONS: Based on the results of our analysis, we can conclude that the utilization of purse strings absorbable sutures for arterial and venous cannulation for cardio-pulmonary bypass in children is safe in relationship to the intraoperative and immediate postoperative period. No complications related to the use of absorbable sutures have been observed in a large pediatric patient population.

Reducing the prevalence of antecubital fossa peripheral intravenous cannulation.

Observational studies have found that placement of peripheral intravenous cannulas (PIVCs) in the antecubital fossa (ACF) is associated with increased risks of infection, including healthcare-associated Staphylococcus aureus bacteraemia (HA-SAB). Avoiding placement of the PIVC in the ACF area along with other preventive measures such as aseptic technique, staff education on documentation, standardised insertion packs and alerts for timely removal, may reduce the overall risk of acquiring an HA-SAB. AIM: To implement a multimodal awareness programme on ACF cannulas and the risk of infection, and to reduce PIVC-associated HA-SAB in one hospital in Australia. METHOD: The authors performed a baseline digital survey to identify root causes for clinical decision making related to PIVCs and to raise awareness of the project. The authors performed weekly audits and provided feedback on four key wards over 12 weeks. Simple linear regression was used to look at the trend of ACF cannulation rates over time. HA-SAB rates were calculated per 10 000 occupied bed days. FINDINGS: Improved insertion documentation was observed during the intervention period. The ACF cannulation rates decreased by 0.03% per day during the study, although this did not quite reach statistical significance (P=0.06). There were no PIVC-associated SAB events during the intervention period. The SAB rates decreased by 0.02% per day over the period of the study.

Acquired von Willebrand syndrome in ECMO patients: A 3-year cohort study.

BACKGROUND: Bleeding is a common but possibly underreported side effect of Extracorporeal Membrane Oxygenation (ECMO). Impairment of primary hemostasis by acquired von Willebrand syndrome (aVWS) and platelet dysfunction as well as activation and consumption of plasmatic coagulation factors contribute to hemorrhage. The aim of the present cohort study of consecutively enrolled patients admitted to our ECMO center was to collect demographic, medical and laboratory data possibly associated with i) development of clinically relevant bleeding and/or ii) death during a 12-months follow-up. RESULTS: Within a 3-year period 338 white patients aged 18-89 years (median: 60; male 64.5%) were enrolled. 78 of 338 patients (23%) presented with clinical relevant bleeding symptoms. The overall death rate was 74.6% within a median time of 9 days (1-229) post intervention. Logistic-regression analysis adjusted for age and gender revealed that i) the presence of blood group O versus non-O (Odds ratio (OR)/95%CI: 1.9/1.007-3.41), ECMO duration per day (1.1/1.06-1.14), veno-venous versus veno-arterial ECMO cannulation (2.33/1.2-4.5) and the overall need for blood product administered per unit (1.02/1.016-1.028) was independenly associated with bleeding in patients suffering from aVWS. ii) Older age (increase per year) at ECMO start (1.015/1.012-1.029) and an increasing amount of blood product units were significantly related with death (1.007/1.001-1.013). Patients with veno-venous versus veno-arterial cannulation survived longer (0.48/0.24-0.94). CONCLUSION: In the present cohort study we found a clinical relevant bleeding rate of 23% in subjects with aVWS associated with blood group O, a longer ECMO duration and veno-venous cannulation.

Incidence of posterior vessel wall puncture during ultrasound guided vascular access: Short axis versus long axis approach.

BACKGROUND AND AIMS: Posterior vessel wall puncture (PVWP) is a common complication of ultrasound (US) guided central venous cannulation. We evaluated and compared the frequency of PWVP of internal jugular vein using short axis (SA) and long axis (LA) approach of US-guided needle cannulation. As a secondary objective incidence of carotid puncture was assessed. MATERIAL AND METHODS: Prospective, single-blinded, cross over, observational study at Urban Level I Neuroanesthesiology and Critical Care Department. Residents receiving standard education on ultrasound-guided central venous cannulation were asked to place an US-guided catheter using either short axis or long axis approach on a human torso mannequin. During the procedure, the path of the needle was carefully observed by the investigator for any PVWP and carotid puncture without interference with the placement procedure. The confidence level of the resident for the intraluminal placement of the needle tip was measured on a 10-point Likert scale. RESULTS: Forty residents participated in the study. The incidence of PVWP in SA and LA group was 40% and 17.5% respectively and was statistically significant (p = 0.026). There was no incidence of carotid artery puncture in either of the group. The mean confidence of intraluminal placement of needle was significantly higher in the LA group (8.32) as compared to the SA group (5.95). CONCLUSION: Lower incidence of PVWP was seen in LA as compared to the SA approach during US-guided IJV cannulation in phantom in residents having previous experience of CVC (central venous cannulation) in landmark technique only. Participants were more confident about intraluminal needle placement in the LA group compared to the SA group.

Application of preoperative assessment of pain induced by venous cannulation in predicting postoperative pain in patients under laparoscopic nephrectomy: a prospective observational study.

BACKGROUND: Postoperative pain is the most prominent concern among surgical patients. It has previously been reported that venous cannulation-induced pain (VCP) can be used to predict postoperative pain after laparoscopic cholecystectomy within 90 mins in the recovery room. Its potential in predicting postoperative pain in patients with patient-controlled intravenous analgesia (PCIA) is worth establishing. The purpose of this prospective observational study was to investigate the application of VCP in predicting postoperative pain in patients with PCIA during the first 24 h after laparoscopic nephrectomy. METHODS: One hundred twenty patients scheduled for laparoscopic nephrectomy were included in this study. A superficial vein on the back of the hand was cannulated with a standard-size peripheral venous catheter (1.1 × 3.2 mm) by a nurse in the preoperative areas. Then the nurse recorded the VAS score associated with this procedure estimated by patients, and dichotomized the patients into low response group (VAS scores < 2.0) or high response group (VAS scores ≥2.0). After general anesthesia and surgery, all the patients received the patient-controlled intravenous analgesia (PCIA) with sufentanil. The VAS scores at rest and on coughing at 2 h, 4 h, 8 h, 12 h, 24 h, the effective number of presses and the number of needed rescue analgesia within 24 h after surgery were recorded. RESULTS: Peripheral venous cannulation-induced pain score was significantly correlated with postoperative pain intensity at rest (rs = 0.64) and during coughing (rs = 0.65), effective times of pressing (rs = 0.59), additional consumption of sufentanil (rs = 0.58). Patients with venous cannulation-induced pain intensity ≥2.0 VAS units reported higher levels of postoperative pain intensity at rest (P < 0.0005) and during coughing (P < 0.0005), needed more effective times of pressing (P < 0.0005) and additional consumption of sufentanil (P < 0.0005), and also needed more rescue analgesia (P = 0.01) during the first 24 h. The odds of risk for moderate or severe postoperative pain (OR 3.5, 95% CI 1.3-9.3) was significantly higher in patients with venous cannulation-induced pain intensity ≥2.0 VAS units compared to those <2.0 VAS units. CONCLUSIONS: Preoperative assessment of pain induced by venous cannulation can be used to predict postoperative pain intensity in patients with PCIA during the first 24 h after laparoscopic nephrectomy. TRIAL REGISTRATION: We registered this study in a Chinese Clinical Trial Registry (ChiCTR) center on July 6 2019 and received the registration number: ChiCTR1900024352.

Epirubicin chemotherapy in women with breast cancer: Alternating arms for intravenous administration to reduce chemical phlebitis.

OBJECTIVE: To establish whether using alternating arms for peripheral intravenous epirubicin administration affects the severity or duration of epirubicin-induced phlebitis. METHODS: An observational study of women with breast cancer (n = 237) in a UK Cancer Centre. Data were analysed after receiving three treatment cycles according to the arm used for epirubicin administration: same, alternating or mixed arm (two consecutive cycles in one arm and one in the alternate arm). Phlebitis severity was graded by clinical staff after each treatment; participants also self-reported symptoms during treatment and for up to 6 months after. RESULTS: The alternating arm group experienced significantly less severe symptoms than the other arm use groups, 6% (4 of 64) compared with 34% (p < 0.001, odds ratio: 0.13 (95% CI: 0.043-0.38) alternating arm compared with same arm group). The alternating arm group reported less pain (p = 0.013), lower overall impact (p = 0.009), lower effect on function (p = 0.032) and shorter duration of symptoms (p = 0.001) than the other arm use groups. CONCLUSION: Using alternating arms for peripheral administration of epirubicin significantly reduces the severity and duration of chemical phlebitis and is recommended to improve patient experience and reduce the need for central venous access devices.

Comparison of Ultrasound-Guided Right Brachiocephalic and Right Subclavian Vein Cannulation in Adult Patients.

OBJECTIVES: To compare ultrasound-guided right brachiocephalic vein (BCV) central venous catheter (CVC) placement to right subclavian vein (SCV) CVC insertion in terms of the puncture success rate and complications. METHODS: A retrospective review was performed for all adult patients who received an ultrasound-guided CVC via the right BCV or right SCV access route between January 2016 and March 2018. The puncture success rates and procedure-related complications were analyzed. RESULTS: Data were analyzed from 755 adult patients who underwent 915 CVC insertions. The overall success rate was higher in the BCV group compared to that in the SCV group (98.99% versus 96.87%; P = .019). The first-attempt success rate was higher in the BCV group compared to that in the SCV group (96.64% versus 89.34%; P < .001). Intraoperative complications were observed in 16 cases in the BCV group (2.68%) and in 12 cases in the SCV group (3.76%). The incidence rates of postprocedure complications were 5.20% in the BCV group and 6.58% in the SCV group and included catheter-related infections and thrombosis. CONCLUSIONS: Ultrasound-guided cannulation of the right BCV is an effective and safe method for CVC placement in adult patients and provides an additional option for catheter access.

Prediction of Acute Postoperative Pain from Assessment of Pain Associated With Venous Cannulation.

BACKGROUND: It has previously been reported that venous cannulation-induced pain (VCP) can be used to predict acute postoperative pain after laparoscopic cholecystectomy. Patients rating VCP at ≥2.0 VAS units had 3.4 times higher risk for moderate or severe pain. The purpose of this study was to evaluate if VCP scores of ≥2.0 VAS units are associated with higher risk for acute postoperative pain after various common surgical procedures. METHODS: In a prospective clinical observational study, 600 male and female 18- to 80-year-old patients scheduled for elective surgery were included. The primary outcome measure was the difference in maximum postoperative pain intensity between low responders (VCP < 2.0) and high responders (VCP ≥ 2.0) to VCP. Secondary outcome measures were the difference in proportion of patients with moderate or severe postoperative pain between low and high responders, and potential influence of age, gender, and preoperative habitual pain. RESULTS: Patients scoring VCP ≥2.0 VAS units reported higher acute postoperative pain intensity levels than those scoring VCP <2.0 VAS units (median 3.0 [interquartile range 0.0 to 5.0] vs. 0.2 [interquartile range 0.0 to 4.0], P = 0.001), and also had 1.7 times higher risk for moderate or severe postoperative pain (P = 0.005). Moderate or severe postoperative pain was reported by 38% of patients with VCP scores of ≥2.0 VAS units and by 26% with VCP scores of <2.0 VAS units (P = 0.005). CONCLUSION: Scoring of VCP intensity before surgery, requiring no specific equipment or training, is useful to predict individual risks for moderate or severe postoperative pain, regardless of patient age or gender, in a setting involving different kinds of surgery.

Value of Routine Sonographic Screening of Internal Jugular Vein to Detect Catheter Related Thrombosis in Intensive Care Unit.

BACKGROUND AND AIMS: Internal jugular vein (IJV) cannulation is a common procedure in the ICU with thrombosis being an uncommon, albeit serious complication. Thrombosis is one of the important complications of IJV cannulation. This study aims to evaluate the use of ultrasound screening by intensivists to assess the incidence of catheter-related IJV thrombosis in ICU. MATERIALS AND METHODS: Fifty consecutive IJV cannulations meeting the inclusion criteria were analyzed in the ICU. Duplex scanning and color doppler sonography were performed by the intensivist on day 3, 6, 9, 12 and 15 after cannulation. The thrombus, when detected, was confirmed independently by a radiologist. The patient demographics, the type of catheter, laterality and the mean duration of catheterization were recorded. Risk factors like presence of circulatory shock, thrombocytosis, DIC, liver disease, and absence of chemoprophylaxis for DVT were documented. RESULTS: A total of 39 patients and 50 cannulations were studied. The mean age of patients was 56.5±16.2 years and mean duration of catheterization was 6.6±2.1 days. We found a 38% (19/50) incidence of thrombosis in our study. There was 100% correlation in detection of thrombosis by the intensivist and the radiologist. The thrombus was detected at 6.9±2.1 days after cannulation. All the patients who developed thrombosis had one or more risk factors. The most common risk factor was circulatory shock (40%). Central line associated blood stream infection (CLABSI) was seen only in the patients in whom IJV thrombus was detected (5/19). CONCLUSION: Catheter-related IJV thrombosis is a frequent complication in ICU patients and is associated with the increased risk of CLABSI. Ultrasound screening is simple, feasible and accurate in diagnosing IJV thrombosis. HOW TO CITE THIS ARTICLE: Bhat MNM, Venkatraman R, Ramakrishnan N, Abraham BK, Rajagopalan S. Value of Routine Sonographic Screening of Internal Jugular Vein to Detect Catheter Related Thrombosis in Intensive Care Unit. Indian J Crit Care Med 2019;23(7):326-328.

Real-time ultrasound-guided axillary vein cannulation in children: a randomised controlled trial.

The axillary vein is a good site for ultrasound-guided central venous cannulation in terms of infection rate, patient comfort and its anatomical relationship with the clavicle and lungs. We compared real-time ultrasound-guided axillary vein cannulation with conventional infraclavicular landmark-guided subclavian vein cannulation in children. A total of 132 paediatric patients were randomly allocated to either ultrasound-guided axillary vein (axillary group) or landmark-guided subclavian vein (landmark group). The outcomes measured were success rate after two attempts, first-attempt success rate, time to cannulation and complication rate. The success rate after two attempts was 83% in the axillary group compared with 63% in the landmark group (odds ratio 2.85, 95%CI 1.25-6.48, p = 0.010). The first-attempt success rate was 46% for the axillary group and 40% for the landmark group (p = 0.274) and median time to cannulation was 156 s for the axillary group and 180 s for the landmark group (p = 0.286). There were no differences in complication rates between the two groups, although three episodes of subclavian artery puncture occurred in the landmark group (p = 0.08). We conclude that axillary vein cannulation using a real-time ultrasound-guided in-plane technique is useful and effective in paediatric patients.

Comparing the effectiveness of vapocoolant spray and lidocaine/procaine cream in reducing pain of intravenous cannulation: A randomized clinical trial.

INTRODUCTION: Venous cannulation is the most common procedure in emergency departments. The aim of this study was to compare the effectiveness of vapocoolant spray and EMLA cream in reduction of pain during venous cannulation in 6-12years old children. METHODS: The study was a randomized clinical trial with a crossover design. It took place between June and December 2015 at Ali-Asghar hospital in Tehran, Iran. 40 Thalassemic children who need regular blood transfusions were randomly assigned in two groups. The pain of intravenous cannulation was measured using a visual analogue scale for pain (VAS-P). With the crossover design each patient received vapocoolant spray and EMLA cream in the next two visits. The patients were allocated into two groups (A and B). The patients in Group (A) received Vapocoolant spray in the first visit and EMLA cream in the second visit before intravenous cannulation. The patients in Group (B) group were exposed to the opposite order. RESULTS: The pain after Vapocoolant spray was 3.22±1.18 which was significantly lower than control (7.12±1.36) and higher than EMLA cream (0.77±1.09), p>0.001. The anxiety before cannulation had a significant effects on the reported pain by children. The ANCOVA showed that despite the effects of anxiety the results did not change significantly. CONCLUSION: The results indicated that vapocoolant spray was not as effective as EMLA cream, in the event of an emergency and in patients with allergic reactions to lidocaine and procaine ingredients Vapocoolant is an efficacious alternative.

Evaluation of optimum time for intravenous cannulation after sevoflurane induction of anesthesia in different pediatric age groups.

BACKGROUND AND AIMS: The ideal time for intravenous (IV) cannulation following inhalational induction in children is debatable. The effect of age on this time has not been studied. We evaluated the optimum time for IV cannulation after sevoflurane induction of anesthesia in different pediatric age groups. MATERIAL AND METHODS: A prospective interventional study based on Dixon's sequential up and down method was conducted in children of age 1-10 years. They were grouped according to their age - Group 1: 1-3 years, Group 2: >3-7 years, and Group 3: >7-10 years. Anesthesia was induced with 8% sevoflurane in 5 L of 100% oxygen. IV cannulation was attempted at 3.5 min in the first child in each group. The time for cannulation in the next child was stepped up or down by 30 s depending on positive or negative response, respectively, in the previous child. Children were recruited till a minimum of six pairs of failure-success sequence which was obtained in each group. The mean of midpoints of the failure-success sequence was calculated to obtain the time for cannulation in 50% of the children in each group. RESULTS: Total number of children in Groups 1, 2, and 3 were 24, 23, and 24, respectively. The mean (95% confidence level) time for IV cannulation after sevoflurane induction in Groups 1, 2, and 3 was 53.6 (40.0-67.1), 105 (62.6-147.4), and 143.6 (108.8-178.4) s, respectively. This time was significantly shorter in Group 1 compared to those in Groups 2 and 3. CONCLUSION: The optimum time for IV cannulation in 50% of the children after sevoflurane induction of anesthesia was shorter in children of age 1-3 years than in older children.

Differences in anatomical relationship between vertebral artery and internal jugular vein in children and adults measured by ultrasonography.

Cannulation of the internal jugular vein (IJV) under ultrasound guidance can reduce complications, such as common carotid artery (CCA) puncture, accidental vertebral artery (VA) puncture. However, these complications still occur, especially in pediatric patients probably due to anatomical predisposition of VA. This study compared differences in anatomical location of VA and IJV between pediatric and adult patients. Children with body weight <20 kg (n = 16) and adults who required central venous or pulmonary arterial pressure monitoring (n = 21) were enrolled. After induction of general anesthesia and tracheal intubation, patients were positioned for IJV cannulation. Images of the right CCA, IJV and VA were recorded by ultrasonography. The size of each vessel, anatomical relationship of other vessels, distance between vessels and between each vessel and skin were measured. The size of VA relative to IJV was significantly larger in children than in adults (14 vs 7 %, P < 0.001). The absolute and relative distance between IJV and VA were significantly shorter in children than those in adults (P < 0.01). The anatomical relationships between IJV and CCA and that between IJV and VA were not different between children and adults. In children, VA was relatively larger and located closer to IJV than adults. The results call for careful attention to the position of VA during ultrasound-guided IJV cannulation especially in children.

Different mechanical properties in Seldinger guide wires.

BACKGROUND AND AIMS: Most central venous catheters are placed using Seldinger guide wires. EN ISO 11070 is the guideline for testing guide wire flexing performance and tensile strength, and we can safely assume that guide wires in use meet these requirements. Unfortunately, EN ISO 11070 guidelines do not reflect the clinical requirements and we continue to see mechanical failures and their associated complications. MATERIAL AND METHODS: This in vitro study was performed in an accredited laboratory. With regard to flexing, we: (1) Established the minimum flexing performance needed to meet clinical requirements, (2) developed flexing performance tests which mimic clinical requirement, and (3) evaluated the mechanical properties of various guide wires relative to these requirements. With regard to tensile strength, we used the testing method prescribed in ISO 11070, but did not end the test at 5 Newton (N). We continued until the guide wire was damaged, or we reached maximum tractive force. We then did a wire-to-wire comparison. We examined two basic wire constructions, monofil and core and coil. RESULTS: Tensile strength: All wires tested, except one, met EN ISO 11070 requirements for 5 N tensile strength. The mean of the wire types tested ranged from 15.06 N to 257.76 N. Flexing performance: None of the wires kinked. The monofil had no evidence of bending. Two core/coil wires displayed minor bending (angle 1.5°). All other wires displayed bending angles between 22.5° and 43.0°. CONCLUSION: We recommend that: (1) Clinicians use guide wires with high-end mechanical properties, (2) EN ISO 11070 incorporate our flexing test into their testing method, raise the flexing requirement to kink-proof, (3) and raise the tensile strength requirement to a minimum of 30 N, and (3) all manufacturers and suppliers be required to display mechanical properties of all guide wire, and guide wire kits sold.

The relative position of femoral artery and vein in children under general anesthesia--an ultrasound-guided observational study.

BACKGROUND: Femoral artery overlaps femoral vein by varying degrees distal to the inguinal ligament, which may result in difficult venous access and also increases the risk of arterial puncture. OBJECTIVE: To study the size of femoral vessels and the degree of overlap in children undergoing anesthesia using ultrasound at 1 and 3 cm distal to inguinal ligament. METHODS: A prospective observational study, 84 children aged <7 years were recruited in six different age groups. An experienced anesthetist identified the femoral vessels and their overlap using ultrasound at two fixed points distal to the inguinal ligament. We also evaluated the correlation of skin puncture site marked as per Advanced Paediatric Life support (APLS) guidance using landmark technique with the ultrasound location of femoral vein beneath the same site. RESULTS: The percentage of children with overlap of femoral vein by femoral artery increases from 5% to 60% as we move distal to the inguinal ligament. At 3 cm distal to inguinal ligament, the incidence of any degree of overlap was statistically significant (P < 0.05) in children <5 years. In 80% of children, the femoral vein was located by ultrasound beneath the skin puncture site as recommended by APLS guidelines. CONCLUSION: A significant increase in femoral vein overlap occurs as we move distal to the inguinal ligament. There is one in five chance of failure to locate femoral vein by landmark technique. In children <2 years, a high approach to femoral vein cannulation under ultrasound guidance is recommended.

Percutaneous retrieval of malpositioned, kinked and unraveled guide wire under fluoroscopic guidance during central venous cannulation.

The placement of central venous catheter using Seldinger's technique, remains a commonly performed procedure with its own risks and benefits. Various complications have been reported with the use of guide wire as well as catheter. We report a unique problem during subclavian vein cannulation due to guidewire malposition which led to its kinking and difficult retrieval requiring removal in fluoroscopy suit. The probable mechanism of guide wire entrapment and possible bedside management of similar problems is described.

Clinical significance of the cross-sectional area of the internal jugular vein.

OBJECTIVES: The aim of this study was to compare the cross-sectional area (CSA) of the right internal jugular vein (IJV) with that of the left IJV and to evaluate the anatomic location of the IJV in relation to the common carotid artery, utilizing computed tomography scans of the neck. DESIGN: Retrospective observational study. SETTING: A tertiary care hospital. PARTICIPANTS: Eighty patients with neck computed tomography scans scheduled for thyroid surgery. INTERVENTION: No. MEASUREMENTS AND MAIN RESULTS: Mean CSA of the right and left IJV were 165±81 and 119±57 mm(2), respectively (p<0.01). A relatively larger CSA of the right IJV, compared with that of the left , was seen in 63 (79%) patients. A larger CSA of the right IJV was shown in more right-handed subjects than left-handed subjects (82 v 43%, p<0.05). Small CSA (<50 mm(2)) of the right or left IJV were seen in 4 patients. Both IJVs were located commonly either laterally or anterolaterally to their common carotid arteries. A posterolateral position of the IJV was seen in 4 patients. CONCLUSIONS: This study suggested one advantage of using the right IJV compared with the left for central venous cannulation. However, anatomic variations of the IJV, such as a small CSA and a medial or posterior position, are not associated with demographic data. Although right-handedness was well-correlated with a larger ipsilateral IJV, a possibility of a larger contralateral IJV should be considered. Therefore, central venous cannulation with ultrasonography is recommended to avoid complications and repeated needling.