Blood conservation for critically ill patients

Extracorporeal membrane oxygenation in Jehovah's Witness patients: Case report, literature review, and summary of recommendations

Extracorporeal Membrane Oxygenation (ECMO) is commonly associated with a high blood transfusion requirement. Jehovah's Witness patients present a particular challenge. The impossibility of transfusing blood cells and starting anticoagulation treatment are common contraindications for this supportive measure. Here we report the case of a Jehovah's Witness patient with refractory hypoxemia due to influenza A H1N1 pneumonia who required venovenous ECMO for 11 days. We describe the use of a bloodless approach to reduce the waste of blood, avoiding anticoagulation, and improving red blood cell production. We then summarize the current literature on the use of ECMO in Jehovah's Witness patients and, finally, we propose some recommendations for their management.

Hemorrhage and Transfusions in the Surgical Patient

Hemorrhage remains the leading cause of intra-operative deaths and those in the first 24 h. Many cardiovascular and hepatobiliary procedures result in massive hemorrhage and postpartum hemorrhage events in labor and delivery place the patient at a high risk for mortality. Both upper and lower gastrointestinal bleeding (e.g., diverticulosis, esophageal and gastric varices, and peptic ulcer disease) can also result in significant blood loss requiring massive transfusion and resuscitation from hemorrhagic shock. Therefore, safe, timely, and effective transfusion of blood products is critical. The aim of this chapter is to provide clinicians with a discussion of the current literature on the various blood component products, their indications, and unique hemostatic conditions in the surgical patient. While the majority of data concerning optimal management of acquired coagulopathy and hemorrhagic shock resuscitation is based on trauma patients, many of the principles can and should be applied to the surgical patient (or likely any patient) with profound hemorrhage.

Profound Anaemia in a Jehovah's Witness following Upper Gastrointestinal Haemorrhage: Intensive Care Management

Management of the profoundly anaemic patient who competently refuses blood transfusion will always prove challenging. This article provides a review of treatment strategies based around a recent case of a patient presenting after major gastrointestinal haemorrhage. The main part of management involves providing supportive intensive care, paying particular attention to oxygen delivery and consumption, and minimising further blood loss. Specific treatments, such as pharmacotherapy to promote erythropoiesis, are based largely on indirect evidence or expert opinion. Virtually all aspects of care involve carefully balancing a shifting profile of risks and benefits; a team approach and close communication with the family are essential. This patient's successful outcome has extended our understanding of this area, which is discussed.

Hemorrhage and Transfusions in the Surgical Patient

Hemorrhage is the leading cause of intraoperative deaths. Many cardiovascular and hepatobiliary procedures result in massive hemorrhage and postpartum hemorrhage events in labor and delivery place the patient at a high risk for mortality. Gastrointestinal bleeding from diverticulosis, varices, and ulcer disease can result in significant blood loss requiring massive transfusion and resuscitation from hemorrhagic shock. Timely and effective transfusion of blood products is of critical in these scenarios. The frequency in which blood component products are transfused in surgical patients begs for a greater understanding of them. The aim of this chapter is to provide clinicians with a discussion of the current literature on the various blood component products, their indications, and unique hemostatic conditions in the surgical patient. While the majority of data concerning optimal management of acquired coagulopathy and hemorrhagic shock resuscitation is based on trauma patients, many of the principles can and should be applied to the surgical patient (or likely any patient) with profound hemorrhage.

Identifying factors to minimize phlebotomy-induced blood loss in the pediatric intensive care unit

OBJECTIVE

Phlebotomy-induced blood loss in critically ill children is common, contributes to anemia, and may be avoidable. We aimed to identify factors associated with phlebotomy-induced blood loss.

DESIGN

Prospective observational study, single-center tertiary children's hospital.

SETTING

Pediatric intensive care unit.

PATIENTS

A total of 63 patients admitted to the pediatric intensive care unit for >48 hrs from 2004 to 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Phlebotomy resulted in a mean blood volume loss of 2.5 ± 1.4 mL per draw, 7.1 ± 5.3 mL per day, and 34 ± 37 mL per pediatric intensive care unit stay, of which 1.4 ± 1.1 mL per draw, 3.8 ± 3.6 mL per day, and 23 ± 31 mL per pediatric intensive care unit stay were discarded as excess. This excess represents 210% ± 174% of the volume requested by the laboratory and a 110% overdraw. Blood drawn from central venous catheters had significantly greater overdraw volumes, 254% ± 112%, compared to those of arterial, 168% ± 44%, and peripheral intravenous catheters, 143% ± 39%, p < .001. Blood draws sent for one test had an associated overdraw of 278% ± 81%, compared to draws sent for two, 168% ± 48%, three 173% ± 4%, and four or greater tests 55% ± 5%, p < .001. Patients <10 kg had significantly greater mean volumes of blood loss/kg/day compared to patients ≥ 10 kg, p < .001.

CONCLUSION

Blood drawn in excess of phlebotomy requirements exceeds the blood volume loss drawn for phlebotomy by two fold. Using indwelling catheters for phlebotomy often requires a discard volume to be drawn before obtaining the laboratory sample. Consolidating phlebotomy tests and using a closed system may decrease the amount of blood overdrawn and minimize overall phlebotomy-induced blood loss.

Packed red blood cell transfusions in critically ill patients

Anemia, which is prevalent in critically ill patients, often requires frequent blood transfusions. These blood transfusions are not without risks. A critical review of 6 studies shows an association between red blood cell transfusion and increased mortality. However, when disease state was adjusted for in 2 studies, researchers found that red blood cell transfusion correlated with decreased mortality. Thus further research, particularly on leukoreduction and age of stored blood, must be done before a change in practice can be implemented. It is vital that nurses stay current on this research in order to improve patients' outcomes.

Red blood cell transfusion in critically ill children: a narrative review

OBJECTIVE

To review the pathophysiology of anemia, as well as transfusion-related complications and indications for red blood cell (RBC) transfusion, in critically ill children. Although allogeneic blood has become increasingly safer from infectious agents, mounting evidence indicates that RBC transfusions are associated with complications and unfavorable outcomes. As a result, there has been growing interest and efforts to limit RBC transfusion, and indications are being revisited and revamped. Although a so-called restrictive RBC transfusion strategy has been shown to improve morbidity and mortality in critically ill adults, there have been relatively few studies on RBC transfusion performed in critically ill children.

DATA SOURCES

Published literature on transfusion medicine and outcomes of RBC transfusion. STUDY SELECTION, DATA EXTRACTION, AND SYNTHESIS: After a brief overview of physiology of oxygen transportation, anemia compensation, and current transfusion guidelines based on available literature, risks and outcomes of transfusion in general and in critically ill children are summarized in conjunction with studies investigating the safety of restrictive transfusion strategies in this patient population.

CONCLUSIONS

The available evidence does not support the extensive use of RBC transfusions in general or critically ill patients. Transfusions are still associated with risks, and although their benefits are established in limited situations, the associated negative outcomes in many more patients must be closely addressed. Given the frequency of anemia and its proven negative outcomes, transfusion decisions in the critically ill children should be based on individual patient's characteristics rather than generalized triggers, with consideration of potential risks and benefits, and available blood conservation strategies that can reduce transfusion needs.

Controversies related to red blood cell transfusion in critically ill patients

OBJECTIVE

To review the evolution of and controversies associated with allogenic blood transfusion in critically ill patients.

DATA SOURCES

Veterinary and human literature review.

HUMAN DATA SYNTHESIS

RBC transfusion practices for ICU patients have come under scrutiny in the last 2 decades. Human trials have demonstrated relative tolerance to severe, euvolemic anemia and a significant outcome advantage following implementation of more restricted transfusion therapy. Investigators question the ability of RBCs stored longer than 2 weeks to improve tissue oxygenation, and theorize that both age and proinflammatory or immunomodulating effects of transfused cells may limit efficacy and contribute to increased patient morbidity and mortality. Also controversial is the ability of pre- and post-storage leukoreduction of RBCs to mitigate adverse transfusion-related events.

VETERINARY DATA SYNTHESIS

While there are several studies evaluating the transfusion trigger, the RBC storage lesion and transfusion-related immunomodulation in experimental animal models, there is little research pertaining to clinical veterinary patients.

CONCLUSIONS

RBC transfusion is unequivocally indicated for treatment of anemic hypoxia. However, critical hemoglobin or Hct below which all critically ill patients require transfusion has not been established and there are inherent risks associated with allogenic blood transfusion. Clinical trials designed to evaluate the effects of RBC age and leukoreduction on veterinary patient outcome are warranted. Implementation of evidence-based transfusion guidelines and consideration of alternatives to allogenic blood transfusion are advisable.

Clinical strategies for supporting the untransfusable hemorrhaging patient

Hemorrhaging patients who cannot be transfused due to personal beliefs or the lack of compatible blood products provide a unique challenge for clinicians. Here we describe a 58-year-old African American man with a history of sickle cell-beta(+) thalassemia who had recently received a multiunit exchange transfusion and developed hematochezia followed by severe anemia. Due to the presence of multiple alloantibodies, no compatible packed red blood cell (pRBC) units could initially be located. The patient was managed with mechanical ventilation, colloid and crystalloid solutions, procoagulants, and recombinant erythropoietin. After an extensive search by our blood bank, enough compatible pRBC units were identified and the patient survived without significant clinical sequelae. Management of the untransfusable hemorrhaging patient requires a multidisciplined approach, with coordination between blood banks, hematologists, intensivists, and other specialists. Steps should be taken to avoid or limit blood loss, identify compatible pRBC units, control hypotension, maximize oxygen delivery, minimize metabolic demand, and stimulate erythropoiesis. In dire circumstances, use of experimental hemoglobin substitutes or transfusion of the least serologically incompatible pRBCs available may be considered.

A study of blood loss from phlebotomy in renal medical inpatients

The objective of the study was to assess phlebotomy loss in renal medical in-patients in order to minimise an iatrogenic cause of anaemia. Phlebotomy has been shown to be a significant cause of iatrogenic blood loss in critical care. However, there has been limited research in patients with renal disease, at risk from anaemia. A prospective observational study was conducted of 70 consecutive patients admitted to an acute renal medicine ward in a tertiary care hospital over a period of four months. Inclusion criteria included adult patients with acute or chronic renal failure. Patients actively bleeding were excluded. Blood loss due to phlebotomy was determined from the patient's computerised records. The mean patient age was 61.5 +/- 16.5 years; the mean length of hospital stay was 23.1 +/- 19.8 days. The mean admission Hb was 9.8 +/- 2.0 g dL(-1) and 9.5 +/- 1.5 g dL(-1) on discharge. The total mean blood loss from phlebotomy during hospitalisation was 215.8 +/- 166 mL with a mean weekly blood loss of 55.7 +/- 11.23 mL. Losses were highest in the first week (mean of 76.8 mL), declining in subsequent weeks. Samples were taken for biochemistry (38%), FBC (36%), transfusion (13%) and others (13%). 46% of patients were transfused (mean 4.8 +/- 3.6 units). Blood loss was lower than in previous studies conducted in intensive care and general medicine but clinical staff should be aware of the cumulative blood loss from phlebotomy. Losses should be managed by optimising the frequency and volume of blood drawn for diagnostic laboratory tests.

DYNAMIC NEAR-INFRARED SPECTROSCOPY MEASUREMENTS IN PATIENTS WITH SEVERE SEPSIS

This study evaluated near-infrared spectroscopy (NIRS)-derived measurements in hemodynamically stable patients with severe sepsis, as compared with similar measurements in healthy age-matched volunteers. Prospective, preliminary, observational study in a surgical intensive care unit and clinical research center at a university health center. We enrolled 10 patients with severe sepsis and 9 healthy age-matched volunteers. For patients with severe sepsis, we obtained pulmonary artery catheter and laboratory values three times daily for 3 days and oxygen consumption values via metabolic cart once daily for 3 days. For healthy volunteers, we obtained all noninvasive measurements during a single session. We found lower values in patients with severe sepsis (versus healthy volunteers), in tissue oxygen saturation (StO2), in the StO2 recovery slope, in the tissue hemoglobin index, and in the total tissue hemoglobin increase on venous occlusion. Patients with severe sepsis had longer StO2 recovery times and lower NIRS-derived local oxygen consumption values versus healthy volunteers. In our preliminary study, NIRS provides a noninvasive continuous method to evaluate peripheral tissue oxygen metabolism in hemodynamically stable patients with severe sepsis. Further research is needed to demonstrate whether these values apply to broader populations of patients with systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock.