Lower Superior Vena Cava Research Articles

Comparison of non-laser and laser transvenous lead extraction: a systematic review and meta-analysis.

Transvenous lead extraction (TLE) is performed using non-laser and laser techniques with overall high efficacy and safety. Variation in outcomes between the two approaches does exist with limited comparative evidence in the literature. We sought to compare non-laser and laser TLE in a meta-analysis. We searched Medline, Embase, Scopus, ClinicalTrials.gov, and CENTRAL databases for TLE studies published between 1991 and 2021. From the included 68 studies, safety and efficacy data were carefully evaluated and extracted. Aggregated cases of outcomes were used to calculate odds ratio (OR), and pooled rates were synthesized from eligible studies to compare non-laser and laser techniques. Subgroup comparison of rotational tool and laser extraction was also performed. Non-laser in comparison with laser had lower procedural mortality (pooled rate 0% vs. 0.1%, P < 0.01), major complications (pooled rate 0.7% vs. 1.7%, P < 0.01), and superior vena cava (SVC) injury (pooled rate 0% vs. 0.5%, P < 0.001), with higher complete success (pooled rate 96.5% vs. 93.8%, P < 0.01). Non-laser comparatively to laser was more likely to achieve clinical [OR 2.16 (1.77-2.63), P < 0.01] and complete [OR 1.87 (1.69-2.08), P < 0.01] success, with a lower procedural mortality risk [OR 1.6 (1.02-2.5), P < 0.05]. In the subgroup analysis, rotational tool compared with laser achieved greater complete success (pooled rate 97.4% vs. 95%, P < 0.01) with lower SVC injury (pooled rate 0% vs. 0.7%, P < 0.01). Non-laser TLE is associated with a better safety and efficacy profile when compared with laser methods. There is a greater risk of SVC injury associated with laser sheath extraction.

Standardized Criteria for Identification of Cardiac Tamponade on Non-Electrocardiogram-gated Computed Tomography: Correlation With Echocardiographic Findings.

To identify imaging parameters that can help in the diagnosis of cardiac tamponade on non-electrocardiogram (ECG)-gated computed tomography (CT) of the chest. Retrospective analysis of 64 patients who had undergone CT and echocardiography for evaluation of cardiac tamponade. Of 64 patients, 34 were diagnosed with tamponade and underwent pericardiocentesis for further diagnosis and treatment. CT measurements obtained were: pericardial effusion (PeEff) pocket size in 6 locations (anterior, posterior, superior, inferior, right, and left lateral), pericardial thickening, diameters of the coronary sinus, upper superior vena cava, lower superior vena cava, and inferior vena cava. In addition, cardiac chamber sizes were measured. Subjective assessment of coronary sinus compression, pericardial enhancement, and pericardial thickening were also recorded. Measurement of the sum of the right lateral and left lateral PeEff thickness resulted in 91.2% sensitivity and 86.7% specificity for cardiac tamponade with a threshold of 30mm (receiver-operating characteristic area under the curve=0.94 [0.84 to 0.98], P <0.0001). Using the combination of inferior PeEff >16mm, sum of right lateral and left lateral PeEff>30mm, and presence of pericardial thickening resulted in 56% sensitivity and 100% specificity and positive predictive value for the determination of cardiac tamponade. Our study suggests that CT measurements related to PeEff size and thickness aid in the diagnosis of cardiac tamponade.

The right supraclavicular fossa ultrasound view for correct catheter tip positioning in right subclavian vein catheterisation: a prospective observational study.

Central venous catheter misplacement is common (approximately 7%) after right subclavian vein catheterisation. To avoid it, ultrasound-guided tip navigation may be used during the catheterisation procedure to help direct the guidewire towards the lower superior vena cava. We aimed to determine the number of central venous catheter misplacements when using the right supraclavicular fossa ultrasound view to aid guidewire positioning in right infraclavicular subclavian vein catheterisation. We hypothesised that the incidence of catheter misplacements could be reduced to 1% when using this ultrasound technique. One -hundred and three adult patients were prospectively included. After vein puncture and guidewire insertion, we used the right supraclavicular fossa ultrasound view to confirm correct guidewire J-tip position in the lower superior vena cava and corrected the position of misplaced guidewires using real-time ultrasound guidance. Successful catheterisation of the right subclavian vein was achieved in all patients. The guidewire J-tip was initially misplaced in 15 patients, either in the ipsilateral internal jugular vein (n = 8) or in the left brachiocephalic vein (n = 7). In 12 patients it was possible to adjust the guidewire J-tip to a correct position in the lower superior vena cava. All ultrasound-determined final guidewire J-tip positions were consistent with the central venous catheter tip positions on chest X-ray. Three out of 103 catheters were misplaced, corresponding to an incidence (95%CI) of 2.9 (0.6-8.3) %. Although the hypothesis could not be confirmed, this study demonstrated the usefulness of the right supraclavicular fossa ultrasound view for real-time confirmation and correction of the guidewire position in right infraclavicular subclavian vein catheterisation.

Venous Thrombosis of the Mammary Vein Following Peripherally Inserted Central Catheter for Total Parenteral Nutrition Relying on Ecg Tip Confirmation Technology

Total parenteral nutrition (TPN) is a life-saving therapy for patients who are not able to utilize the gastrointestinal tract. There are several different types of central venous catheters (CVC) used to deliver TPN. To safely deliver hyperosmotic TPN solutions, CVC tip position should be in the in lower superior vena cava (SVC) or at the junction of SVC and right atrium (RA). New techniques such as intravascular electrocardiogram (ECG) are being used for tip confirmation to help facilitate expedient use of PICC lines replacing the need for chest x-ray (CXR) confirmation. We present a case of a TPN patient who had a PICC line placed, and ECG confirmed tip as being in the SVC. The patient developed chest pain with flushing of the PICC prompting surgical service to obtain a CXR. The CXR suggested the line was in the either in mammary vein or aorta and recommended replacement. Interventional radiology flushed a small amount of contrast through the PICC and fluoroscopy confirmed the PICC tip was in the left internal mammary vein with reflux of contrast in the left innominate vein. The left innominate vein was occluded due to thrombosis and vasospasm. The patient required increased level of care (PCU) for 2 days, but was eventually discharged with home total parenteral nutrition and has done well. We conclude that care should be taken when using ECG confirmation for PICC tip placement and we feel that patients requiring hyperosmotic TPN should still require CXR confirmation to ensure tip appropriate tip location.

The Perimetric Protuberance-Periosteal Chondroma

Total parenteral nutrition (TPN) is a life-saving therapy for patients who are not able to utilize the gastrointestinal tract. There are several different types of central venous catheters (CVC) used to deliver TPN. To safely deliver hyperosmotic TPN solutions, CVC tip position should be in the in lower superior vena cava (SVC) or at the junction of SVC and right atrium (RA). New techniques such as intravascular electrocardiogram (ECG) are being used for tip confirmation to help facilitate expedient use of PICC lines replacing the need for chest x-ray (CXR) confirmation. We present a case of a TPN patient who had a PICC line placed, and ECG confirmed tip as being in the SVC. The patient developed chest pain with flushing of the PICC prompting surgical service to obtain a CXR. The CXR suggested the line was in the either in mammary vein or aorta and recommended replacement. Interventional radiology flushed a small amount of contrast through the PICC and fluoroscopy confirmed the PICC tip was in the left internal mammary vein with reflux of contrast in the left innominate vein. The left innominate vein was occluded due to thrombosis and vasospasm. The patient required increased level of care (PCU) for 2 days, but was eventually discharged with home total parenteral nutrition and has done well. We conclude that care should be taken when using ECG confirmation for PICC tip placement and we feel that patients requiring hyperosmotic TPN should still require CXR confirmation to ensure tip appropriate tip location

Minimal guidewire length for central venous catheterization of the right subclavian vein: A CT-based consecutive case series.

Central venous catheter (CVC) misplacement occurs frequently after right subclavian vein catheterization. It can be avoided by using ultrasound to confirm correct guidewire tip position in the lower superior vena cava prior to CVC insertion. However, retraction of the guidewire during the CVC insertion may dislocate the guidewire tip from its desired and confirmed position, thereby resulting in CVC misplacement. The aim of this study was to determine the minimal guidewire length required to maintain correct guidewire tip position in the lower superior vena cava throughout an ultrasound-guided CVC placement in the right subclavian vein. One hundred adult patients with a computed tomography scan of the chest were included. By using multiplanar reconstructions from thin-sliced images, the distance from the most plausible distal puncture site of the right subclavian vein to the optimal guidewire tip position in the lower superior vena cava was measured (vessel length). In addition, measurements of equipment in common commercial over-the-wire percutaneous 15-16 cm CVC kits were performed. The 95th percentile of the vessel length was used to calculate the required minimal guidewire length for each CVC kit. The 95th percentile of the vessel length was 153 mm. When compared to the calculated minimal guidewire length, the guidewires were up to 108 mm too short in eight of eleven CVC kits. After confirmation of a correct guidewire position, retraction of the guidewire tip above the junction of the brachiocephalic veins should be avoided prior to CVC insertion in order to preclude dislocation of the catheter tip towards the right internal jugular vein or the left subclavian vein. This study shows that many commercial over-the-wire percutaneous 15-16 cm CVC kits contain guidewires that are too short for right subclavian vein catheterization, i.e., guidewire retraction is needed prior to CVC insertion.

WHEN EDEMA ISN'T ANGIOEDEMA: SUPERIOR VENA CAVA SYNDROME AS A CONFOUNDER IN HEREDITARY ANGIOEDEMA

Introduction Hereditary Angioedema (HAE) is characterized by bradykinin-mediated nonpitting, nonpruritic edema. Superior vena cava (SVC) syndrome often presents with facial swelling and dyspnea; benign etiologies comprise up to 40% of the known causes, most commonly caused by intravascular devices. We report the case of a patient with known HAE complicated by concomitant SVC syndrome. Case Description A 45-year-old white male with known HAE presented with a four-hour history of facial swelling and progressive dyspnea. The patient had throat and bilateral hand swelling. He was treated with C1 esterase inhibitor through an implanted central venous access port, which terminated in the lower SVC. His respiratory status declined, necessitating intubation. A C1 esterase inhibitor functional level drawn early in the hospital course was normal. The patient remained edematous throughout the admission. C1q and C4 levels were inconsistent with an acute HAE flare. A CT chest revealed chronic occlusions of the upper extremity vasculature concerning for an SVC syndrome. Eventually, the patient was successfully extubated. After discharge, a venacavogram revealed an occlusion of the superior vena cava above the junction with the right atrium. Discussion SVC syndrome is a possible confounding factor in patients with HAE flares. Despite the availability of subcutaneous formulations of C1 esterase inhibitor, many patients still receive intravenous C1 esterase inhibitor. The utilization of central venous access ports for medication administration in this population raises the risk of non-HAE mediated edema from SVC syndrome. Additionally, increased vascular pressures in SVC syndrome may also contribute etiologically to acute HAE flares. Hereditary Angioedema (HAE) is characterized by bradykinin-mediated nonpitting, nonpruritic edema. Superior vena cava (SVC) syndrome often presents with facial swelling and dyspnea; benign etiologies comprise up to 40% of the known causes, most commonly caused by intravascular devices. We report the case of a patient with known HAE complicated by concomitant SVC syndrome. A 45-year-old white male with known HAE presented with a four-hour history of facial swelling and progressive dyspnea. The patient had throat and bilateral hand swelling. He was treated with C1 esterase inhibitor through an implanted central venous access port, which terminated in the lower SVC. His respiratory status declined, necessitating intubation. A C1 esterase inhibitor functional level drawn early in the hospital course was normal. The patient remained edematous throughout the admission. C1q and C4 levels were inconsistent with an acute HAE flare. A CT chest revealed chronic occlusions of the upper extremity vasculature concerning for an SVC syndrome. Eventually, the patient was successfully extubated. After discharge, a venacavogram revealed an occlusion of the superior vena cava above the junction with the right atrium. SVC syndrome is a possible confounding factor in patients with HAE flares. Despite the availability of subcutaneous formulations of C1 esterase inhibitor, many patients still receive intravenous C1 esterase inhibitor. The utilization of central venous access ports for medication administration in this population raises the risk of non-HAE mediated edema from SVC syndrome. Additionally, increased vascular pressures in SVC syndrome may also contribute etiologically to acute HAE flares.

Brisk Upper Gastrointestinal Bleeding From Isolated Proximal Esophageal Varices

GI bleeding from isolated proximal esophageal varices, known as downhill varices, is a rare phenomenon comprising about 0.1% of all esophageal variceal bleeding. Superior vena cava (SVC) obstruction can impair systemic venous return and lead to the development of proximal esophageal collateralization resulting in varices. While most cases of downhill varices occur due to malignant SVC obstruction, benign causes have been reported. We describe an unusual case of benign high-grade SVC obstruction resulting in brisk downhill variceal bleeding. A 34 year-old woman with systemic lupus erythematosus complicated by ESRD requiring hemodialysis presented with large-volume hematemesis and melena. The patient had a similar presentation 16 months prior and had undergone EGD showing an actively bleeding Mallory Weiss tear and prominent proximal esophageal veins. Physical exam was notable for multiple tortuous and dilated superficial veins throughout abdomen. Urgent EGD was performed revealing grade II esophageal varices isolated to the proximal third of the esophagus with a fibrin plug. Band ligation was successfully performed. On further history, the patient revealed that over the last year she has had 9 right internal jugular central dialysis catheter placements due to repeated catheter thrombosis. A chest CT was obtained and demonstrated a high-grade short segment stenosis of the lower SVC with numerous prominent collateral vessels along the mediastinum and chest wall. The patient subsequently underwent angiography with balloon dilation and stent placement, with dramatic improvement in her physical exam findings of dilated abdominal wall veins within 24 hours. She has had no further GI bleeding. This is a rare case of hemodialysis catheter-associated SVC obstruction leading to proximal esophageal variceal bleeding in a young patient without mediastinal malignancy. Treatment for SVC obstruction varies based on the etiology and can include treating the primary malignancy, thrombolysis, balloon dilation and/or stent placement in cases of benign stenosis. Downhill variceal bleeding should be considered in patients presenting with upper GI bleeding with established or suspected SVC obstruction. Endoscopists must carefully examine the proximal esophagus and consider prophylactic intubation for airway protection. If isolated proximal esophageal varices are incidentally identified, contrast enhanced imaging of the chest is indicated to evaluate for SVC obstruction.

Limited Ultrasound Protocol for Upper Extremity Peripherally Inserted Central Catheter Monitoring: A Pilot Study in the Neonatal Intensive Care Unit.

To assess whether a limited ultrasound (US) scanning protocol to monitor the upper extremity peripherally inserted central catheter (PICC) location in neonates is feasible for experienced US operators. A radiologist, who was blinded to the PICC location on chest radiography, performed 14 US scans on 11 neonates with upper extremity PICCs. A US machine with 13-6-MHz linear and 8-4-MHz phased array transducers was used for the examinations. The study population included 54% (n = 6) preterm infants, with 72% (n = 8) weighing less than 1500 g. The US location of the PICC was the same as the chest radiographic report in all 14 scans. A subclavicular long-axis view of the anterior chest visualized all PICCs in the subclavian or brachiocephalic veins. A parasternal long-axis right ventricular inflow view was able to visualize PICCs in the superior vena cava (SVC), and a subcostal long-axis view evaluated PICCs in the lower SVC and heart. The scanning time was location dependent: less than 5 minutes for PICCs in the brachiocephalic or subclavian vein and 5 to 10 minutes for PICCs in the SVC or heart. There were no desaturations below 90%, increases in the fraction of inspired oxygen need, or hypotension episodes during scanning. A limited US scanning protocol to determine the upper extremity PICC location is feasible. Our protocol needs to be tested in neonatal providers before further dissemination.

Stress Echocardiographic Evaluation for D-Transposition of the Great Arteries after Atrial Redirection: Unmasking Early Signs of Myocardial Dysfunction and Baffle Stenosis

The authors used semisupine cycle ergometry stress echocardiography to assess cardiac function and unmask baffle stenosis in patients with d-transposition of the great arteries after atrial redirection surgery. This was a retrospective review of semisupine cycle ergometry stress echocardiography performed in 53 patients (64% male; mean age, 24.0years; 90% Mustard procedure) and 56 healthy control subjects. Incremental exercise to volitional fatigue was performed. Hemodynamic data, echocardiographic cardiac dimensions, area change, tissue Doppler velocities, strain, ventricular synchronization, and superior vena cava flow velocities before and immediately after exercise are reported. Patients had lower exercise capacity (870 vs 1,854 J/kg, P<.001) and peak heart rates (132 vs 167 beats/min, P<.001). Stroke volume index did not increase with exercise (45 vs 47mL/m2, P=.400). Cardiac index increased in both groups with exercise (3.0 vs 6.1 and 2.9 vs 7.0L/min/m2, P<.001) and was higher in control subjects (P=.006). Right ventricular diastolic and systolic areas decreased significantly with exercise in both the short-axis and four-chamber views. Right and left ventricular contraction time shortened with exercise (405 vs 247 and 338 vs 217msec, P<.001) and remained synchronous (ratio of right ventricular to left ventricular contraction time=0.080). Doppler velocities in patients with baffle obstruction were higher in the lower superior vena cava with exercise compared with nonobstructed patients (1.87 vs 1.46m/sec, P=.020) and normalized after catheter intervention (1.49 vs 1.46m/sec, P=.800). Patients with d-transposition of the great arteries have lower exercise capacity and peak heart rates. The systemic right ventricle presents a lesser but qualitatively normal systolic response and decreased diastolic filling. Semisupine cycle ergometry stress echocardiography unmasked SVC obstruction.

AAGBI Safe vascular access guidelines I

I congratulate the Working Party for their helpful and interesting vascular access guidelines 1. I have two questions. Firstly, the guidelines recommend positioning the tip of a central venous catheter in the lower superior vena cava or upper right atrium. Is there clear evidence to prove that the risk of death from erosion and cardiac tamponade at this site is lower than the risk of death from thrombosis associated with high superior vena cava tip positions (above the pericardial reflection), or does this recommendation represent the Working Party's expert consensus? Concerning immediate vessel perforation, the guidelines state that dilators should only be inserted as far as is needed to open a track to the target vessel, and yet manufacturers routinely supply long dilators. Have the Working Party contacted manufacturers requesting that only 4 cm dilator are supplied as standard, with a longer one available on request in a single item pack?

Accuracy of Intravenous Electrocardiography Confirmation of Peripherally Inserted Central Catheter for Parenteral Nutrition.

Parenteral nutrition (PN) is a life-saving therapy for patients with intestinal failure. Safe delivery of hyperosmotic solution requires a central venous catheter (CVC) with tip in the lower superior vena cava (SVC) or at the SVC-right atrium (RA) junction. To reduce cost and delay in use of CVC, new techniques such as intravascular electrocardiogram (ECG) are being used for tip confirmation in place of chest x-ray (CXR). The present study assessed for accuracy of ECG confirmation in home PN (HPN). Records for all patients consulted for HPN from December 17, 2014, to June 16, 2015, were reviewed for patient demographics, diagnosis leading to HPN initiation, and ECG and CXR confirmation. CXRs were subsequently reviewed by a radiologist to reassess location of the CVC tip and identify those that should be adjusted. Seventy-three patients were eligible, and after assessment for research authorization and postplacement CXR, 17 patients (30% male) with an age of 54 ± 14 years were reviewed. In all patients, postplacement intravascular ECG reading stated tip in the SVC. However, based on CXR, the location of the catheter tip was satisfactory (low SVC or SVC-RA junction) in 10 of 17 patients (59%). Due to the high osmolality of PN, CVC tip location is of paramount importance. After radiology review of CXR, we noted that 7 of 17 (41%) peripherally inserted central catheter lines were in an unsatisfactory position despite ECG confirmation. With current data available, intravenous ECG confirmation should not be used as the sole source of tip confirmation in patients receiving HPN.

Ultrasound confirmation of central venous catheter position via a right supraclavicular fossa view using a microconvex probe

Visualisation of a central venous catheter (CVC) with ultrasound is restricted to the internal jugular vein (IJV). CVC tip position is confirmed by chest radiography, intracardiac ECG or transoesophageal/transthoracic echocardiography (TEE/TTE). We explored the feasibility, safety and accuracy of a right supraclavicular view for visualisation of the lower superior vena cava (SVC) and the right pulmonary artery (RPA) as an ultrasound landmark for real-time ultrasound-guided CVC tip positioning via the right IJV. Ultrasound was then compared with chest radiography. An observational pilot study. Bonn, University Hospital, Germany. From July to October 2012. Fifty-one patients scheduled for elective surgery. Reasons for exclusion were emergency procedure, thrombosis or small IJV lumen and mechanical obstacle to guidewire advancement. In 48 patients, CVC insertion via the right IJV and progress of the guidewire into the lower SVC were continuously guided by an ultrasound transducer in the right supraclavicular fossa. CVC tip position in lower SVC and tip-to-carina distance were assessed with chest radiography as a reference method and additionally with TEE in cardiothoracic patients. Insertion depth was compared with intracardiac ECG and body-height formula. The guidewire tip was seen in the SVC of all patients. In four patients, the tip was not visible in proximity of the RPA. Chest radiography and TEE confirmed CVC tip position in the lower SVC (zone A). Bland-Altman analysis revealed an average of difference of 1.6 cm for ultrasound versus ECG (95% limit of agreement -2 to 5 cm) and an average of difference of 1 cm for ultrasound versus body-height formula (95% limit of agreement -2 to 4 cm). Ultrasound via a right supraclavicular view is a feasible, well tolerated and accurate approach and should be further explored. Chest radiography confirmed CVC position in the lower SVC.

The supraclavicular fossa ultrasound view for central venous catheter placement and catheter change over guidewire.

The supraclavicular fossa ultrasound view can be useful for central venous catheter (CVC) placement. Venipuncture of the internal jugular veins (IJV) or subclavian veins is performed with a micro-convex ultrasound probe, using a neonatal abdominal preset with a probe frequency of 10 Mhz at a depth of 10-12 cm. Following insertion of the guidewire into the vein, the probe is shifted to the right supraclavicular fossa to obtain a view of the superior vena cava (SVC), right pulmonary artery and ascending aorta. Under real-time ultrasound view, the guidewire and its J-tip is visualized and pushed forward to the lower SVC. Insertion depth is read from guidewire marks using central venous catheter. CVC is then inserted following skin and venous dilation. The supraclavicular fossa view is most suitable for right IJV CVC insertion. If other insertion sites are chosen the right supraclavicular fossa should be within the sterile field. Scanning of the IJVs, brachiocephalic veins and SVC can reveal significant thrombosis before venipuncture. Misplaced CVCs can be corrected with a change over guidewire technique under real-time ultrasound guidance. In conjunction with a diagnostic lung ultrasound scan, this technique has a potential to replace chest radiograph for confirmation of CVC tip position and exclusion of pneumothorax. Moreover, this view is of advantage in patients with a non-p-wave cardiac rhythm were an intra-cardiac electrocardiography (ECG) is not feasible for CVC tip position confirmation. Limitations of the method are lack of availability of a micro-convex probe and the need for training.

The malfunctioning infusion port: can the chest radiograph predict need for revision?

Purpose Malfunction of chest infusion ports leads to unnecessary peripheral IV placement and delays in infusion. When this occurs in our institution, the patient is sent for a contrast injection study. The port is injected looking for evidence of a fibrin sheath. Since tip location is the most important factor contributing to fibrin sheath formation, this expensive and potentially harmful study could be avoided if there was a way to predict the likelihood of intervention based on the tip location on chest radiograph. Materials and Methods A retrospective single-center review was performed after approval by our IRB. The chest radiographs of 60 consecutive patients who underwent 62 individual port studies within a two year period (2010-2012) were reviewed and the tip location of the port catheter was recorded. Tip locations were divided anatomically into ten zones, with appropriate position residing in zones 4 and 5 (lower 1/3 superior vena cava (SVC) and right atrium (RA)). If a tip was in a location other than 4 and 5 it was deemed “inappropriate.” The medical records of the patients were then reviewed and the findings of the port study and the outcome of the port was recorded. Results Sixty patients, (21 male and 39 female, age range 18-82) underwent 62 individual port studies preceded by frontal chest radiography. Of 62 port studies, 42 (68%) were found to be within appropriate tip zone (lower SVC or RA), and 20 (32%) were found to be malpositioned. Twelve (29%) of the appropriately positioned ports required intervention, whereas nine (45%) of the malpositioned ports were intervened upon. (p = 0.00056). Conclusion A significantly greater proportion of catheters who have a tip location outside the lower SVC and RA need to be revised or removed as opposed to ports with their catheter tip in this location. We suggest that the clinical workup of a patient with a malfunctioning infusion port start with a standard chest radiograph. If the port tip is outside of the lower SVC or RA, then a port study is unnecessary and the patient should be referred for removal or revision. The application of this screening method for infusion port studies can help reduce cost and radiation exposure to the patient.

Application and comparison of modified in vitro PICC measurement in children with blood cancer

Objective To explore the best in vitro PICC measurement in children with blood cancer. Methods 70 cases of hematology-oncology patients who aged from 1 to 7 years old from June,2009 to July, 2010 in Pediatric Hematology Oncology were selected and divided randomly into the control group and the observation group with 35 cases in each group. The measurement of the control group was from the pre-puncture point along the vein to the right chest acromioclavicular joint, the measurement of the observation group was from the pre-puncture point along the vein to 1cm below the right chest acromioclavicular joint. Results The rate of PICC placed in the lower superior vena cava was 94.29% in the observation group, and 57.14% in the control group, the difference was significant. Conclusions For children patients aged from 1 to 7 years old with blood cancer, PICC catheter length measurement from the prepuncture point along the vein to 1cm below the right chest acromioclavicular joint, can improve accuracy for the PICC into the lower superior vena cava. Key words: Peripherally inserted central catheter; Leukemia; Children; External measurement methods

Transesophageal Echocardiography in the Diagnosis of Thrombosis Associated with Permanent Transvenous Pacemaker Electrodes

We sought to assess the value of transesophageal echocardiography (TEE) in the diagnosis of PM-lead-associated central venous thrombi. Venous thrombosis is not infrequent after pacemaker (PM) or implantable cardioverter-defibrillator (ICD) implantation. Previous incidence studies of thrombosis have been based on venography or Doppler ultrasound, but the role of TEE has not been systematically evaluated in this setting. Study group comprised 66 consecutive patients (mean age 64 years, 67 % male) referred for implantation of their first PM or ICD and with a successful TEE, transthoracic echocardiography (TTE) and venography at 6 months after implantation. The total number of implanted leads was 110. During the 6 months of clinical follow-up, nuclear ventilation-perfusion scan or spiral computed tomography was performed when symptoms aroused a clinical suspicion of PE. TEE revealed a right atrium (RA) or lower superior vena cava (SVC) thrombus in 6 (9%) patients. These thrombi were not visualized by TTE or venography. Additionally, 12 (20%) patients were found to have venographic subclavian or innominate vein thrombi, but none of those could be diagnosed with TEE. Symptomatic pulmonary embolism (PE) was diagnosed in two and an asymptomatic PE in one individual and two of these occurred among the six patients with a thrombus in TEE. No clinical predictors for thrombosis were found. TEE is an excellent method to visualize electrodes within the RA and proximal SVC. Electrode-associated RA thrombi appear to be relatively common after PM implantation, and they may remain undetectable by venography or TTE. Although these thrombi are mostly asymptomatic, they can give rise to pulmonary embolism and should also be kept in mind in the differential diagnosis of endocarditis. TEE is the method of choice for the diagnosis of these lesions.

The clinical investigation of extracorporeal vein bypass during lobectomy combined with superior vena cava graft for lung cancer

To evaluate the benefits of three methods of extracorporeal vein bypass from superior vena cava (SVC) to femoral vein during lobectomy and SVC graft in patients with lung cancer. Fifty-five cases selected from the patients with lung cancer who had undergone lobectomy combined with SVC graft by sortilege were divided into 3 groups: blood discarding group ( n =20), blood drainage group ( n =20) and extracorporeal bypass group ( n =15). The mean arterial pressure (MAP) and SVC pressure were continuously monitored during the SVC graft. Hemoglobin (Hb) was measured before and during the SVC clamping and after the SVC off clamping. During SVC clamping, the patients in extracorporeal bypass group had a significantly lower SVC pressure than blood discarding group and blood drainage group, and there were significant decreases in MAP and Hb and increase in blood loss in blood discarding group than the other two groups. All the patients underwent a smooth operation and safely returned to intensive care unit. None of them involved any neurologically injured signs and symptoms. Extracorporeal SVC bypass can maintain a very stable hemodynamics and low SVCP during SVC resection and artificial vessel graft, which is an avail of brain perfusion and blood saving.

PH-stat blood gas management provides better cerebral perfusion during deep hypothermic retrograde cerebral perfusion

We performed a retrospective comparative clinical study to evaluate whether pH-stat (n=14) or alpha-stat strategy (n=15) provides better perfusion or oxygen metabolism during hypothermic retrograde cerebral perfusion (RCP). The pH-stat group showed significantly lower superior vena cava (SVC) pressure (21+/-4 versus 27+/-6 mmHg, P<0.0001), apparently lower retrograde cerebral vascular resistance index (7.4+/-2.1 versus 10.1+/-3.8 dynes/s cm(-5) m(-2), P=0.009) but there were no significant differences in RCP flow index, oxygen supply or oxygen extraction between groups. Further studies are necessary to determine which blood gas management is better for RCP, however, pH-stat strategy should be useful in deep hypothermic RCP.

Embolized Air Collection in the Superior Vena Cava of ???Upright??? Sheep

In 34 studies on six "upright" anesthetized sheep central venous pressure from sites in the upper and lower superior vena cava (SVC) was recorded before, during, and after the injection into a neck vein of 1-ml increments of air every minute for 15 min. After the injection of air, the pressure recorded from the upper site increased significantly. This increase was the result of air collecting in the SVC with a consequent loss or partial loss of the SVC hydrostatic pressure difference. The time of onset and the duration of collection were not influenced by hyper- or hypovolemia nor by 1 kPa positive end-expiratory pressure. The readily identifiable change in the venous pressure in the upper SVC provided an earlier and more reliable warning of these small-volume air emboli than did a Doppler probe directed at the right side of the heart.