More than 15 million Americans have chronic kidney disease of which approximately 500,000 require dialysis.1 The annual death rate in the United States for dialysis patients in 2007 was 212 deaths per 1000 patient-years.1 Cardiac disease is the single leading cause of death for both hemodialysis and peritoneal dialysis patients.1 Arrhythmic mechanisms or sudden cardiac arrest is implicated in 60% of all cardiac deaths in dialysis patients in the United States Renal Data System database.1-3
Dialysis patients sustaining cardiac arrest or an arrhythmia suffer poor long term survival, with a two-year mortality rate of 74%.4 Karnik et al5 reported a 48 hour mortality rate of 60% in a study of 400 cardiac arrest patients on dialysis. In a study of 74 in-hospital dialysis patients, long term survival after CPR was strikingly poor at 92%, with a six month mortality rate of 97%.6 A retrospective study that reviewed 24 patients who had CPR during dialysis in a small medical center over a 3 year period, reported a mortality rate of 100%.7
It is difficult to accurately apportion the absolute percentage of cardiac death directly attributable to complications of ischemic heart disease or arrhythmia mechanisms, as almost every dialysis patient has some level of underlying cardiac disease, placing them at risk for sudden death.1,8 Hypertension, myocardial hypertrophy, coronary artery disease, and congestive heart failure are extremely common in the dialysis population.9 Greater than 90% of dialysis patients have hypertension placing them at risk factor for sudden death.10 Continued hypertension leads to increased left ventricular hypertrophy (present in 75% of dialysis patients),11 and the prevalence of cardiomyopathy increases with time on dialysis.12 While structural disease is important, baseline problems with cardiac electrical activity are also common in dialysis patients associated with coronary artery disease and electrolyte imbalances. The QT interval, a measure of re-polarization and predictor of sudden death, is often prolonged in dialysis patients.13,15 The QT dispersion, a measure of the differences in time of the QT interval in different leads of the electro-cardiogram, is increased in dialysis patients and is also a risk factor for sudden death.14,15 As years on dialysis increase, cardiac abnormalities tend to worsen.15
End stage kidney disease with dialysis causes several additional stressors not seen in the general population with heart disease. Hemodialysis causes significant fluid fluxes resulting in repeated bouts of predialysis volume overloading and intra or postdialysis hypotension; each is a potent stressor in its own right. Similarly, potassium and other electrolytes undergo large fluxes with hemodialysis, and hyperkalemia or hypokalemia are known to precipitate sudden death and or cardiac arrhythmias.5 Based on these facts, researchers have done extensive retrospective studies and reported nearly a 50% increased frequency of sudden cardiac death on Mondays (for patients dialyzing Monday, Wednesday, and Friday), and similar trends on Tuesdays (for patients on a Tuesday, Thursday, Saturday) schedule.5,16, 22 A retrospective study to identify cardiac arrest cases at a community outpatient dialysis centers over 14-years identified 102 cardiac arrests, 10 occurred before, 72 during and 20 after hemodialysis.17 All were related to ventricular fibrillation or tachycardia. It is important to note that the overwhelming majority of sudden deaths occur outside of dialysis centers.18
The risk for cardiovascular death in ESRD patients is approximately 20 times greater than in the general US population.12,19-21 End stage renal disease patients should be considered high risk patients. When planning to use hyperbaric oxygen therapy a more aggressive work-up is warranted, including a 12 lead EKG and chest x-ray, further testing may be needed based on test results. Lab values may be of little use as they can change with each dialysis treatment, however a patient weight prior to each treatment may be useful in identifying potential volume overload. Pre and post HBO vital signs should be done with caution to ensure that they are not performed on the arm with an arteriovenous fistula/shunt. No blood draws including finger stick blood glucose levels should be taken on an arm with an arteriovenous fistula/shunt. Blood born infections are the second leading cause of death in dialysis patients.1 Manual blood pressures should be taken, as this allows the nurse or HBO technician a clear opportunity to notice an irregular pulse. Chamber operators should closely monitor these patients throughout each treatment. Any observed or patient centered concerns should immediately lead to termination of treatment. Post treatment all dialysis patients should be examined by the HBO physician to ensure that the patient is stable prior to discharge. A majority of the evidence suggests that HBO should be provided post dialysis, when these patients are at their most hemodynamically stable point. Based on the patient’s dialysis schedule, treatments on Mondays and Tuesdays morning should be avoided altogether until dialysis is completed. This may require working with the dialysis centers to adjust treatment times, thereby ensuring a higher level of patient safety.
1. US Renal Data System: USRDS 2009 Annual Data Report. Bethesda, Maryland, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Disease, 2009.
2. Herzog CA. Cardiac arrest in dialysis patients: Approaches to alter an abysmal outcome. Kidney International. 2003; 63 (Suppl 84): S197-S200.
3. US Renal Data System: USRDS 2001 Annual Data Report. Bethesda, Maryland, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Disease, 2001.
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5. Karnik JA, Young BS, Lew NL. et al. Cardiac arrest and sudden death in dialysis units. Kidney International. 2001; 60: 350-357.
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21. Henry RM, Kostense PJ, Bos G, et al. Mild renal insufficiency is associated with increased cardiovascular mortality: the Hoorn study. Kidney International. 2002; 62: 1402-1407.
22. Lafrance JP, Nolin L, Senecal L, et al. Predictors and outcome of cardiopulmonary resuscitation (CPR) calls in a large hemodialysis unit over a seven-year period. NDT. 2006; 21: 1006-1012.