Routine Blood Sampling May Increase the Chance of Developing Iatrogenic Anemia and Introduce Bloodstream Infection Risks
Critically ill patients are more numerous and severely ill than ever before.1 To effectively care for these patients, clinicians rely on physiologic monitoring of blood flow, oxygen transport, coagulation, metabolism, and organ function.
This type of monitoring has made the collection of blood for testing an essential part of daily management of the critically ill patient, yet it is widely recognized that excessive phlebotomy has a deleterious effect on patient health and may contribute to iatrogenic anemia. The process of obtaining a blood sample from an indwelling central venous or arterial catheter also requires a volume of diluted blood (2–10 mL) to be discarded or “cleared” from the catheter before a sample can be taken, adding to blood loss during phlebotomy.2,3
Almost 95% of patients admitted to an intensive care unit have an Hgb concentration that is below normal by day three of admission, often requiring blood transfusion.4 It has also been shown that phlebotomy accounts for 49% of the variation in the amount of red blood cells (RBC) transfused.2
Despite evidence to support a restrictive transfusion practice, the transfusion of packed red blood cells (PRBC) remains a primary intervention for the treatment of ICU patients with anemia.5 Blood transfusions are associated with negative effects on patient outcomes, including increased risk for infection, which may explain the positive correlation between organ dysfunction and the number of blood draws.6,7,8,9
Catheter-related bloodstream infection (CRBSI) is the most common nosocomial bacteremia in critically ill patients.10 It affects nearly 50,000 patients each year in the US, with an attributable mortality of up to 35% and a financial cost of up to $30,000 per case.11
Reducing Blood Waste or "Discard Volume" During Diagnostic Phlebotomy by Using a Closed Blood Sampling System Can Help Reduce Patient Risk
Closed, in-line blood conservation systems (BCS), such as ICU Medical's SafeSet®, eliminate the need to discard the clearing volume associated with sampling through indwelling arterial catheters, reducing blood loss as well as the potential for bacterial ingress into the closed system.12
A closed, in-line BCS also reduces clinician exposure to potential bloodborne pathogens during the sampling process. Accordingly, the ability to reinfuse blood discard with SafeSet may help reduce cases of anemia in the ICU, and subsequently reduce unnecessary transfusions.
By eliminating open systems and minimizing points for bacterial ingress, closed, in-line BCSs may significantly reduce arterial and central line contamination.13 One study found the use of a BCS correlated with lower rates of intraluminal fluid contamination compared to a traditional three-way open-port stopcock system.
The ability of a BCS to prevent microbial contamination is further enhanced by incorporating needlefree connectors into the sampling port stopcock. A study comparing conventional open sampling systems to self-sealing valve connectors within a post-surgical cardiothoracic ICU reported a 4.3% hub colonization rate with valve connectors and a 14.2% colonization rate with open sampling systems.14 The study also reported 10.9% catheter tip colonization with the self-sealing valve connectors and 17.2% colonization rate with open sampling systems (See Figure 1).
The pervasive anemia experienced by the majority of patients in the ICU is minimized by the utilization of closed, in-line blood sampling and conservation systems. By reducing blood loss and the potential for iatrogenic anemia, closed blood sampling and conservation systems help reduce the need for and inherent risk of transfusions in the ICU.
In addition, the application of closed blood sampling and conservation systems prevents the transfer of bacteria into the catheter and helps clinicians in their efforts to minimize catheter-related bloodstream infections.
- Barie, P. Phlebotomy in the intensive care unit: strategies for blood conservation. Critical Care 2004, 8(Suppl 2):S34-S36.
- Corwin HL, Parsonnet KC, Gettinger A. RBC transfusion in the ICU. Is there a reason? Chest 1995, 108:767-771.
- Zimmerman JE, Seneff MG, Sun X, Wagner DP, Knaus WA. Evaluating laboratory usage in the intensive care unit: patient and institutional characteristics that influence frequency of blood sampling. Crit Care Med 1997, 25:737-748.
- Corwin HL. Erythropoietin use in critically ill patients: forest and trees. CMAJ 2007; 17(7):747-749.
- Hebert PC, Wells G, Blajchman MA, Marshall J, Martin C, Pagliarello G, Tweeddale M, Schweitzer I, Yetisir E. The transfusion requirements in critical care investigators for the Canadian critical care trials group: a multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. N Engl J Med 1999, 340:409-417.
- Vincent JL, Baron JF, Reinhart K, et al. Anemia and blood transfusion in critically ill patients. JAMA 2002;288:1499-507.
- Tinmouth AT, McIntyre LA, Fowler RA. Blood conservation strategies to reduce the need for red blood cell transfusion in critically ill patients. CMAJ 2008, 178:49-57.
- von Ahsen N, Muller C, Serke S, Frei U, Eckardt KU. Important role of nondiagnostic blood loss and blunted erythropoietic response in the anemia of medical intensive care patients. Crit Care Med 1999, 27:2630-2639.
- Ottino G, De Paulis R, Pansini S, Rocca G, Tallone MV, Comoglio C, Costa P, Orzan F, Morea M. Major sternal wound infection after open-heart surgery: a multivariate analysis of risk factors in 2,579 consecutive operative procedures. Ann Thorac Surg 1987, 44:173-179.
- Valles J, Leon C, Alvarez-Lerma F. Nosocomial bacteremia in critically ill patients: a multicenter study evaluating epidemiology and prognosis. Clin Infect Dis 1997;24:387e395.
- Wenzel RP, Edmond MB. Team-based prevention of catheterrelated infections. N Engl J Med 2006;355:2781e2783.
- Mukhopadhyay A, Yip HS, Prabhuswamy D, Chan YH, Phua J, Lim TK, et al. The use of blood conservation device to reduce red blood cell requirements: a before and after study. Crit Care 2010;14:R7.
- Peruzzi WT, Noskin GA, Moen SG, Yungbluth M, Lichtenthal P, Shapiro BA. Microbial contamination of blood conservation devices during routine use in the critical care setting: results of a prospective, randomized trial. Crit Care Med 1996, 24:1157-1162.
- Bouza E, Munoz P, Lopez-Rodriguez J, et al. A needleless closed system device (CLAVE) protects from intravascular catheter tip and hub colonization: a prospective randomized study. J Hosp Infect 2003;54:279e287