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Patient Safety Tip of the Week

December 7, 2021

The Hidden Dialysis Catheter



One of the first patient safety incidents we investigated over thirty years ago was a case of massive blood loss in a patient undergoing dialysis (see our March 26, 2007 Patient Safety Tip of the Week “Alarms Should Point to the Problem”). An ESRD patient was having his regularly scheduled dialysis session. Since he would be in the dialysis center for several hours, he was in a comfortable lounge chair that tipped back. Also, since it was somewhat cool, he was offered a blanket to keep warm. Midway through the dialysis session, the low-pressure alarm rang. The nurse turned off the alarm and eyeballed the patient and saw no blood. Nothing further was done. Soon thereafter the low pressure alarm triggered again. This time it was recognized that the dialysis catheter had become dislodged and the patient had, in fact, had considerable blood loss. It had not been appreciated immediately because the blanket had been covering up the catheter site and the blood, rather than being visible on the floor, had been pooling in the webbing of the lounge chair.


The thrust of our March 26, 2007 Patient Safety Tip of the Week “Alarms Should Point to the Problem” was that alarm system setups should focus visual attention to that part of the system where the problem originates. Anyone who has ever spent time in an ICU or other high tech medical environment knows that the usual first response to an alarm is to turn the alarm off. Proper design of medical equipment therefore should force the responder to focus on the source of the problem. In the case at hand, the equipment and alarm were on the side of the patient opposite from the involved limb so that the visual attention of the responder was not directed immediately to the site the alarm was drawing attention to.


A second consideration was the complexity of the alarm screen. That complexity may lead to responders simply taking the easy way out and clearing the alarm, particularly if they anticipate the alarm will be re-triggered if something serious is really going on. The most reliable patient safety interventions are forcing functions. We’ve, therefore, suggested that these alarm systems program in a “hard” stop for this particular alarm that requires the responder to verify that he/she has inspected the access site. That verification should then become part of the medical record.


In our April 25, 2017 Patient Safety Tip of the Week “Dialysis and Alarm Fatigue” we discussed a case with striking similarities to that in our previous column (CDPH 2017). A patient admitted with an MI suffered deterioration of his chronic renal disease and was begun on continuous renal replacement therapy (CRRT) with a femoral catheter for dialysis access (technically, it was continuous veno-venous hemofiltration or CVVH). For comfort, the patient was covered with a blanket, which obscured the catheter access site. Unfortunately, at some point the return line became loose and disconnected from the femoral catheter which caused massive blood loss and cardiac arrest. He received CPR and blood transfusions and was resuscitated but died several days later. That case had a cascade of errors that all contributed to the fatal incident (see the prior column for details) but, once again, failure to heed the alarm was a major one.


In both the cases described in our prior columns, blankets had obscured the access sites. In yet another case of a dislodged dialysis needle (see our December 10, 2019 Patient Safety Tip of the Week “Dialysis Line Dislodgements”) a blanket also covered the access site (Fields 2010). So, that is a recurrent theme. Use of the blankets is a well-intentioned effort to keep the patients comfortable. But it obviously subverts the recommendation to maintain visualization of the access site at all times. We’ve previously recommended that, if a blanket is necessary, it should be one that has a substantial cut-out section that allows adequate visualization of the access site.


Recently, a report from the Veterans Health Administration (Walton 2021) identified 281 bleeding events, including 14 deaths, during hemodialysis treatments over an 18-year period. The onset of the bleeding was unwitnessed in 67% of the cases, leading to a delay in its discovery and intervention. Most deaths were associated with central venous catheter access. 33% of root cause analyses identified physical barriers to direct observation or an equipment issue as root causes.


Of the 14 bleeding events that resulted in death from catastrophic hemorrhage, 11 (79%) deaths were associated with hemodialysis through a central venous catheter and 3 (21%) deaths were reported in patients receiving hemodialysis through a vascular shunt or graft.


In every fatal event, bleeding was discovered only after irreversible hemorrhage had occurred. Mental status and the failure to maintain visibility of the access site were significant contributors to fatal events. In 57% of deaths, alteration of mental status or confusion contributed. Likewise, in 57% of deaths the access site was not visible to the staff because of physical environmental barriers blocking the view or the access site was covered and concealed from view. Both alteration of mental status and a dialysis site that was obscured from view were present in 36% of fatal cases.


An alteration to the patient’s mental or behavioral health status contributed to 19% of all bleeding events, whereas 31% were unintentionally disconnected by a patient with normal mental status. In 8, bleeding was the result of an intentional action by the patient such as disconnection of the dialysis machine from the shunt/graft in a moment of anger or frustration, and opening the hemodialysis ports or cutting through the central dialysis catheter in an attempted suicide.


In their review of root causes analyses (RCA’s) of these cases, Walton et al. highlighted four areas of attention and concern:


1.     The physical location and the equipment being used during hemodialysis.
The physical layout of the dialysis unit may obscure direct line of sight to the patient. Staff may not be competent in the operation of the hemodialysis equipment or no plan for managing equipment malfunctions has been established. Importantly, they note that reliance on pressure-sensing alarms is not recommended because this technology is known to be unreliable.


2.     Staff commitment to standardization and attention to detail.
The majority of bleeding events occur unwitnessed and often associated with a failure to maintain direct observation of the patient and/or the hemodialysis access site during the treatment. Covering the patient with a blanket or bedding resulting in concealment of the hemodialysis access site is a known contributing factor to unrecognized bleeding events. Recommendations to mitigate bleeding risk during hemodialysis include staff attention to detail when preparing the vascular access shunt or graft site and the secure taping of the needles, ensuring bloodlines run unobstructed from the patient to the dialysis machine and securing connecting points to prevent separation with clips, and maintaining visibility at all times to the vascular access site and bloodline connections. Patient safety checklists are suggested as an important preventive intervention.


3.     The mental status of the patient.
Altered mental status is often associated with hemodialysis-related bleeding event, including those unrecognized and those deemed self-harming acts, both intentional and unintentional. The authors note that patients receiving chronic hemodialysis have significantly higher rates of depression and suicidal ideation and are known to engage in suicidal acts, commonly associated with incision of a peripheral arteriovenous shunt or graft in the outpatient setting. Close observation is needed in patients with alteration of mental status. They mention that physical restraint may be considered but must be used judiciously, as it exposes patients to additional risk and potential adverse outcomes. Psychological support services should be a part of the multidisciplinary team of every patient on chronic hemodialysis.


4.     The method for hemodialysis delivery.
Central venous catheters have been associated with significant and fatal bleeding events in both the inpatient and outpatient settings. Exsanguination from a central venous catheter if unchecked can occur within minutes. Guidance from  the Centers for Medicare & Medicaid Services and the Kidney Disease Quality Outcome Initiative recommend that central venous access catheters remain in place no longer than 90 days to avoid complications including bleeding. Furthermore, the use of a central venous catheter was found to present more than one point of failure, including dislodgment, disconnection, and uncapping.


Many of these recommendations were discussed in our December 10, 2019 Patient Safety Tip of the Week “Dialysis Line Dislodgements”. In that column we noted a review (Saha 2017) that noted the following major factors leading to needle dislodgement:

·       Issues related to access care (improper taping of access tubing to the skin, loose luer lock tubing connection, bloodlines not being looped loosely, or access site not being visible)

·       Patient factors (eg. a confused patient pulling the needle out of the access)

They describe the role of the venous alarm monitor but note that multiple factors aside from venous pressure can affect the alarm. Plus, there are differences in venous pressure between grafts and fistulas. As a result of wide variation in venous pressures, staff often set the alarm thresholds at levels below that at which a dislodgement should have triggered an alarm. They then discuss various sensors that can detect blood leaks during venous needle dislodgement, noting the tradeoff between safety and cost.


In that column we also noted the work of the American Nephrology Nurses’ Association (ANNA) Venous Needle Dislodgement Special Project Workgroup (Axley 2012), which reviewed recommendations of care for venous needle dislodgement prevention and detection. They developed a set of easy-to-use tools outlining their recommendations. These focused especially on the procedures for taping and positioning of needles and lines. But they stressed that vascular access and needles should be visible at all times during hemodialysis. Checking the vascular access should be part of the monitoring routine. And, most importantly, “When the venous pressure alarm is activated, the vascular access, needle sites, and blood line positions should always be inspected prior to resetting the alarm and/or the alarm limits.” They also discussed the importance of patient and staff education about needle dislodgement, including caution that alarm systems are not infallible. They also included a risk assessment tool to help identify patients at high risk for venous needle displacement. When such high risk patients are identified, they suggest interventions such as stabilizing the access limb, using one-on-one monitoring, and consideration of a blood leak detection device.


Likewise, The Renal Association (The Renal Association 2018) recommends that connections and lines are kept in full view of dialysis staff during dialysis, secured with tape if necessary, and that any alarm should prompt visual inspection of these. It is customary in most units to place the dialysis machine on the same side as patient access, a practice we have recommended since our first column. They recommend local dialysis nursing supervision guidelines should be adhered to, though these vary from unit to unit. Some units have double-checking of line connections by 2 nurses included in their protocols for starting dialysis.


The excellent work of Walton et al. adds to a growing body of literature on these disastrous bleeding incidents during hemodialysis. Heeding the advice in their study and our prior columns hopefully can help prevent similar incidents in your facilities.



Some of our prior columns on dialysis, CKD, and ESRD:


March 26, 2007           “Alarms Should Point to the Problem”

February 2009             “Unintended Consequences of eGFR Reporting”

May 2009                    “Erythropoiesis-Stimulating Agents and Mortality”

September 20, 2011    “When Practice Changes the Evidence: The CKD Story”

September 2013          “Is Nephrologist Caseload Related to Dialysis Mortality?”

September 2014          “New Tubing Connections”

June 23, 2015              “Again! Mistaking Antiseptic Solution for Radiographic Contrast”

November 1, 2016      “CMS Emergency Preparedness Rule”

April 25, 2017             “Dialysis and Alarm Fatigue”

July 16, 2019              “Avoiding PICC’s in CKD”

December 10, 2019     “Dialysis Line Dislodgements”

February 4, 2020         “Drugs and Chronic Kidney Disease”

October 2021              “Overdoing It on CKD?”






CDPH (California Department of Public Health). Complaint Intake Number: CA00471877; posted 4/20/2017



Fields R. When Needles Dislodge, Dialysis Can Turn Deadly ProPublica 2010; Nov. 10, 2010



Walton E, Charles M, Morrish W, Soncrant C, Mills P, Gunnar W. Hemodialysis Bleeding Events and Deaths: An 18-Year Retrospective Analysis of Patient Safety and Root Cause Analysis Reports in the Veterans Health Administration. J Patient Saf. 2021 September 24, 2021



Saha M, Allon M. Diagnosis, Treatment, and Prevention of Hemodialysis Emergencies. Clinical Journal of the American Society of Nephrology 2017; 12(2): 357-369



Axley B, Speranza-Reid J, Williams H. Venous needle dislodgement inpatients on hemodialysis. Nephrology Nursing Journal 2012; 39(6): 435-445



The Renal Association (UK). Severe blood loss in haemodialysis patients from dialysis line disconnection and femoral catheter removal. July 23, 2018







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