Subintimal catheter tip placement
Submitted by Kate Laidlow, Clinical Nurse Specialist IV Therapy at Lakes DHB. Originally printed in June 2007 IVNNZ Inc. Newsletter
Nurses, generally, have always insisted on blood aspiration of any central venous catheter (CVC) before the administration of fluids or medication. The following case study confirms the reason why nurses continue to practice this. It is a timely reminder for nurses about one of the more rare complications. This can happen so easily and is considered life threatening. I hope you find the following case discussion enlightening and empowering.
Demographics
A Surgical setting, where CVCs are commonplace.
A 33yr old lady, of mäori descent, was suffering with effects of a malignant neoplasm of the pancrease. She'd had many CVC's for her total parenteral nutrition, (TPN), requirements. All previous catheters had occluded for a variety of reasons. This lady had high dependency needs. She was one of 5 patients the nurse was caring for.
The nurse was a senior nurse with much experience with CVC cares. She was struggling to keep up with her high intestinal output from nasogastric (NG) and vomiting. The lady was generally very unwell with poor pain control, had a very complex family situation, wanting to self-discharge and be at home with her 4-week-old baby. This scene is set to highlight how easily it is to miss something potentially life threatening in complex working situations, unless set procedural guidelines are followed carefully and routinely.
Day of the event:
The patient had a quadruple (4) lumen CVC sited in the left subclavian vein. She was receiving TPN via the distal lumen and had had 2500mls of TPN over the last seventeen hours. It was bag change time. During routine changeover the nurse flushes the lumen with 20ml 0.9% sodium chloride (NaCl) using a turbulent flush. The first step is blood aspiration to confirm catheter placement in the vascular space. This blood aspiration did not happen.
The nurse tried all the usual checks and tricks before my involvement. My assessment, unfortunately, confirmed her findings. The patient had no other symptoms, however every body's anxiety remained high due to previous multiple CVC occlusions, re-sites, and general illness.
Further investigation defined an anaesthetic blind insertion, non traumatic with post insertion radiograph the day before. The tip placement confirmed as intravascular, in the superior vena cava (SVC), between 4th and 5th thoracic vertebrae. The only thing of note was the lady's excessive vomiting and pain over the previous 24hrs.
Radiology was consulted and fluoroscopy requested.
During fluoroscopy the radiologist noted the hand pushed dye injection received some resistance. When filmed we saw dye travel up then dispersed into the SVC circulation at the level of the proximal lumen exit.
The radiologist confirmed a subintimal space placement of the catheter tip.
Mosbys' dictionary, 1998, defines the subintirmal space as the area beneath the intima or membrane lining a blood vessel, usually a large artery.
Further examination of the tip placement showed that the tip was at the junction of the innominate vein and the SVC. There was no change in external catheter length in the 24 hours since insertion.
Tip placement.
Anatomical landmarks on radiographs are the indicators for accurate tip placement. There is varying opinion as to the optimal position of the tip of the catheter. The majority opinion supports placement in the lower third of the SVC, Defalque & Campbell (1978) cited in Vesely (2003) use the 5th and 6th thoracic vertebrae as landmarks. Aslamy & Rutherford (1994) cited in Vesley (2003) support this with further useful landmarks being the right tracheobronchial angle and the catheter tip is 3cm below this angle. Controversially many renal interventionalists believe that performance and durability of the catheter will be improved by positioning the catheter within the upper right atrium (RA).
In 1997 The Society or Cardiovascular and Interventional Radiology, cited in Vesley (2003), produced guidelines that essentially leave tip position to the discretion of the operating physician. This then leaves the nurse with a lack of consensus to consider and a degree of risk when caring for these patients. Our question remained, how had the tip migrated without any external length change?
Other factors to consider when viewing radiographs is to look for sharp bends on the catheter that could suggest the tip in an a aberrant vein such as the azygous, hemiazgos or internal mammory vein. Sometimes subintermal placement can be identified as "slack" in the intravascular portion of the line. Ellis, Vogal & Copeland (1989). For nursing that means a fade in the line and definition of this should never be left to nursing to interpret. The inserting physician before use should identify this after insertion.
Side and site of the catheter placement are often discussed with many believing that the right internal jugular is the best site due to the direct approach and minimal chance of butting up against the vein wall. This avoids eroding the wall lining with continuous TPN and tip contact. This is defined as the abutted catheter, Wickham, Purl & Welker (1992), and poses significant risk of erosion.
Nursing Implications.
A life-threatening situation was avoided and I praise the nurse for her identification of a catheter complication. Had the TPN been left to continue how long would it have taken before complete erosion occurred or pericardial tamponade happened. Routine blood aspiration avoids this risk.
The patient is always on the move, either independently or though our nursing cares. With movement comes a natural migration or travel of the catheter tip. Knowing that this happens re-enforces the need to always have blood aspirate to confirm the tip is in the vascular space.
This lady had an excessive amount of vomiting, causing pressures change within the thoracic cavity when the patient coughs or vomits. An a-butted catheter during vomiting or movement is very irritating to the intima lining of the vessel wall. Again nursing will do well to consider and highlight factors as an increased risk of erosion and subintimal placement when assessing patients.
Blood aspirate of any CVC is vital, with much controversy about its need remaining within the health care setting. This case has clearly identified, for nursing at Lakes DHB, the importance of continual blood aspiration prior to administering anything though any CVC. Additional knowledge surrounding tip placement, subintimal space and erosion have been most helpful and have become strong education and competence assessment points. Unfortunately however, to date, the subject of subintimal placement is lacking in researched incidence and rare in its finding.
Lack of blood aspirate should always be identified and further investigation requested by nurses. Lack of blood aspirate equates to the removal of the CVC unless radiological interpretation deems it safe for nurses to continue with catheter use. This is supported by set procedural guidelines, rigorous continual assessment and accurate documentation of all activity with the CVC by all physicians and nurses on a daily basis throughout its use.
Our lady had this catheter removed after 48hours by a surgical registrar and observed very closely. She went home to her family after some additional palliative surgery and died early this year surrounded by her children.
References:
Anderson, KN Anderson, LE & Glanze, WD (Ed) Mosbys medical, nursing and allied health dictionary, 5th Ed: St Louis: Mosby (1998)
Ellis, L. Vogal, S. & Copeland, E. (1989) Central venous catheter vascular erosion. Diagnosis and clinical course. Annals of surgery. V.209 (4); 476-479
Vesely, T.M. (2003) Central venous catheter tip position: A continuing controversy. Journal of vascular and interventional radiology. 14 (5): 527-534
Wickman, R. Purl, S. & Welker, D. (1992) Long-term central venous catheters: Issues for care. Meditheses. Clinical topics in vascular access. 1992; 8 2(May): 133-147