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Autopsy Cardiac Examination
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
The SA node is generally invisible. It is a horseshoe/saddle-shaped structure lying immediately subepicardially within the terminal groove on the lateral aspect of the junction of the superior vena cava and the RA (seeFig. 1.21). Because the sinus node is not visible grossly, the entire block of tissue from the area where the superior caval vein meets the right atrial appendage should be taken as a rectangular longitudinal section to include the proximal superior vena cava and atrial appendage wall (seeFig. 1.22). The block is divided in two and embedded face down where divided (Fig. 1.39) in one block, usually number 8 in routine practice. Sections are cut parallel to the long axis of the superior vena cava. The SA node is an epicardial structure and microscopically the node consists of small diameter, haphazardly orientated atrial muscle cells admixed with connective tissue (Fig. 1.40). Many nerve bundles and ganglion cells are noted in the vicinity of the SA node. Often, the artery to the SA node can be identified in the centre of the nodal tissue. The artery supplying the sinus node is a branch of the right coronary artery in 50% of people and from the left circumflex coronary artery in the other 50%. In small infants, it is preferable to section the entire cavoatrial junction serially. There is no anatomical evidence for the existence of specialized pathways between the SA and AV nodes, but electrophysiologically, fast and slow fibre pathways are identified which can be ablated during life for supraventricular tachycardias.
Vascular access
Published in Mark Davenport, James D. Geiger, Nigel J. Hall, Steven S. Rothenberg, Operative Pediatric Surgery, 2020
Marcus D. Jarboe, Ronald B. Hirschl
Ideal catheter tip position was discussed above. The cavoatrial junction can be approximated on fluoroscopy as 1.5–2 vertebral bodies inferior to the carina. Therefore, after tunneling to the access site and before placement through the introducer into the IJ, the catheter length is measured. This can be done with either a wire or by laying the catheter on the patient's chest while using fluoroscopy. The catheter is then cut to length and advanced through the introducer. The introducer is removed, and proper position is confirmed with fluoroscopy. Target vessels of such cut-downs include the external jugular vein, facial vein, IJ vein just above the clavicle, and the proximal greater saphenous vein. Overall, the cut-down technique has been largely replaced by percutaneous access. However, the cut-down technique remains an important skill that is indispensable in many circumstances.
Paediatric cases
Published in Lt Col Edward Sellon, David C Howlett, Nick Taylor, Radiology for Medical Finals, 2017
The U VC also allows fluids and medication to be administered and is used for blood sampling. The catheter passes from the umbilical vein up to the left portal vein then courses through the ductus venosus into the IVC. The optimum tip position is at the right cavoatrial junction.
Atrial fibrillation induced by peripherally inserted central catheters
Published in Baylor University Medical Center Proceedings, 2020
Reshma Golamari, Yub Raj Sedhai, Abubaker Jilani, Karthik Ramireddy, Priyanka Bhattacharya
Peripherally inserted central catheters are placed by specialized nursing staff or interventional radiology; they are long and flexible, commonly made of nonthrombogenic material like silicone or polyurethane,3 and inserted into the cephalic vein, basilic veins, or brachial vein using an ultrasound-guided antecubital insertion technique, with the patient’s arm abducted to 90° from the body and the head turned toward the ipsilateral side. This positioning is particularly useful to straighten the curve in the subclavian vein and decrease the angle between the subclavian and internal jugular veins.4 The PICC courses along the subclavian vein to terminate at the junction of the superior vena cava and right atrium, with the optimal position being the distal third of the superior vena cava. The right tracheobronchial angle is the best landmark to identify the cavoatrial junction.4 A postprocedural chest radiograph is often obtained to confirm the placement. Fluoroscopy and transesophageal echocardiogram are other methods to confirm the placement.5
Antithrombogenic peripherally inserted central catheters: overview of efficacy and safety
Published in Expert Review of Medical Devices, 2019
Amanda J. Ullman, AndreW. C. Bulmer, Tim R. Dargaville, Claire M. Rickard, Vineet Chopra
The benefit promised by anti-thombogenic PICCs will need to withstand other factors that impact on thrombus development. Factors such as patient (e.g., prior thrombosis, cancer, critical illness), device (e.g., lumen number, tip location, catheter-to-vessel ratio), and provider (e.g., inserter experience, number of attempts) all contribute to the development of PICC-associated thrombosis [3,14]. Starting with insertion, variability in inserter technique and competence using the steel needle introducer can mean more or less vessel damage may occur at the outset. This is in addition to patients who may already be coagulopathic or with existing vessel frailty or damage. If the distal catheter tip is positioned outside of the distal superior vena cava or cavoatrial junction, there is a further increased risk for thrombosis [48]. During the weeks or months of dwell ahead, factors such as the catheter/vessel ratio, and the activity level of the patient will subject the vessel wall to repeated and ongoing physical contact with the catheter. It remains to be seen whether PICC material advancements can withstand these important sources of thrombus development. Finally, it may be that not all thrombus associated with PICCs is unwanted. The role of non-symptomatic thrombosis remains unclear clinically, and this may even have some protective effect against other unwanted adverse events, such as vessel wall rupture or insertion site irritation.
Utility of venous blood gases in severe sepsis and septic shock
Published in Baylor University Medical Center Proceedings, 2018
Heath D. White, Alfredo Vazquez-Sandoval, Pedro F. Quiroga, Juhee Song, Shirley F. Jones, Alejandro C. Arroliga
All three samples were collected in standard blood gas syringes in a sequential manner within a time frame of no more than 15 minutes. Clinical personnel collected all blood gas samples using standard blood gas collection methods, and the samples were transported on ice to a central laboratory. The ABG was collected by either needle puncture or withdrawal from an arterial catheter. The cVBG was collected from any catheter that terminated at the cavoatrial junction. Catheter placement was confirmed by chest radiograph by study personnel. The pVBG was collected from the upper extremity, and a tourniquet could be left in place for no more than 1 minute. Blood gas samples were then analyzed using a blood gas analyzer (Radiometer model ABL 700 series, Radiometer America, Inc., Westlake, OH) as part of routine processing. Data including pH, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), bicarbonate (HCO3), base excess (BE), and oxyhemoglobin saturation (O2 saturation) were recorded. Other data including the use of vasopressors and presence of mechanical ventilation were collected as well.