Therapeutic apheresis in neurology critical care

Therapeutic apheresis has been widely accepted in the treatment of neurological disorders that are understood to be mediated by humoral and/or cellular immunity. The clinical presumption is that well-established and/or unknown insults cause damage to nerves or their myelin sheaths. The rationale for apheresis treatments for these neurological disorders relates to removal of offending immune (or other) mediators, thus blunting the attack and permitting recovery of nerve and/or myelin. This review will concentrate on the role of therapeutic apheresis, in particular therapeutic plasma exchange, in neurological disorders that may frequently be seen by intensivists.     

Glucocorticoid therapy in neurologic critical care

BACKGROUND: The pivotal role of inflammation and edema across the spectrum of central nervous system injury has driven extensive investigation into the therapeutic potential of glucocorticoids. OBJECTIVE: To review the experimental and clinical data relating to the efficacy and adverse effects of glucocorticoids in conditions encountered in critical neurologic and neurosurgical illness. DATA SOURCE: Search of MEDLINE and Cochrane databases, manual review of article bibliographies. DATA SYNTHESIS AND CONCLUSIONS: The efficacy of glucocorticoids is well established in ameliorating edema associated with brain tumors and in improving outcome in subsets of patients with bacterial meningitis. Despite frequently encouraging experimental results, clinical trials of glucocorticoids in ischemic stroke, intracerebral hemorrhage, aneurysmal subarachnoid hemorrhage, and traumatic brain injury have not shown a definite therapeutic effect. The evidence supporting glucocorticoid therapy for spinal cord injury is controversial; however methylprednisolone continues to be widely employed in this setting.     

Nurses' knowledge and attitudes about antibiotic therapy in critical care.

PURPOSE: To assess critical care nurses' knowledge about antibiotic use in critical care settings, and attitudes concerning the role of the nurse in monitoring response to and appropriate use of antibiotic therapy. METHOD: 90 critical care nurses from 6 adult critical care units at a 780-bed academic, health sciences centre, completed an investigator-developed survey about their knowledge of antibiotic use and their attitudes concerning the role of the nurse. RESULTS: The majority of respondents worked full time (83%) and were BSN (Bachelor of Science in Nursing) prepared (62%), with an average of 9 years' nursing experience and 7 years' experience in intensive care. Using a 100-mm visual analog scale, mean scores on knowledge and comfort with: (1) interpreting culture and sensitivity; (2) white blood cell (WBC) data; and (3) discussing results and therapy with physicians were all less than 50 mm. However, the mean score for nurses' belief of responsibility related to this collaborative role was 76. A knowledge quiz of lab interpretation and antibiotic therapy revealed a mean score of 53.8%. Beliefs about roles were correlated with comfort in discussing therapies with physicians rather than with knowledge. Although nurses value the collaborative surveillance role, they may lack the knowledge and confidence to enact it.     

Efficacy of different low-density lipoprotein apheresis methods.

Low-density lipoprotein (LDL) apheresis is a treatment option in patients with coronary heart disease and drug resistant hypercholesterolemia. Various apheresis systems based on different elimination concepts are currently in use. We compared the efficacy of 4 different apheresis systems concerning the elimination of lipoproteins. The study included 7 patients treated by heparin extracorporeal LDL precipitation (HELP), 10 patients treated by immunoadsorption, 8 patients treated by dextran-sulfate adsorption, and 4 patients treated by cascade filtration. Ten subsequent aphereses were evaluated in patients undergoing regular apheresis for more than 6 months. Total cholesterol decreased by approximately 50% with all 4 systems. LDL cholesterol (LDL-C) (64-67%) and lipoprotein a [Lp(a)] (61-64%) were decreased more effectively by HELP, immunoadsorption, and dextran-sulfate apheresis than by the less specific cascade filtration system [LDL-C reduction 56%, Lp(a) reduction 53%]. Triglyceride concentrations were reduced by 40% (dextran-sulfate) to 49% (cascade filtration) and high-density lipoproteins (HDL) by 9% (dextran-sulfate) to 25% (cascade filtration). On the basis of plasma volume treated, HELP was the most efficient system (LDL-C reduction 25.0%/L plasma), followed by dextran-sulfate (21.0%/L plasma), cascade (19.4%/L plasma), and immunoadsorption (17.0%/L plasma). However, a maximal amount of 3 L plasma can be processed with HELP due to concomitant fibrinogen reduction while there is no such limitation with immunoadsorption. Therefore, the decision of which system should be used in a given patient must be individualized taking the pre-apheresis LDL concentration, concomitant pharmacotherapy, and fibrinogen concentration into account.     

Critical care apheresis: hepatic failure.

Hepatic failure is a common feature of critical care. Most hepatic dysfunction in the ICU responds to medical management and metabolic support. The role of extracorporeal organ support in hepatic failure is not as well defined as it is in renal failure and pulmonary failure. Nevertheless, artificial organ support has been successful in the treatment of advanced liver failure. Hybrid bioartificial liver substitutes show great promise, especially as a bridge to liver transplant.     

Efficacy of fentanyl analgesia for trauma in critical care transport

INTRODUCTION: Pain relief is one of the most important interventions for out-of-hospital patient care providers. This paper documents the need for and benefits from the administration of fentanyl to trauma patients during critical care transport. METHODS: We underwent a retrospective review of the transport charts of 100 trauma patients who received fentanyl analgesia during transport and who were able to use a numeric response scale to rate their pain from 0 to 10. RESULTS: Mean initial pain report was 7.6 +/- 2.2 units, relieved to 3.7 +/- 2.8 units by a mean total fentanyl dose of 1.6 +/- 0.8 microg/kg (P < .001). Neither initial pain level nor pain relief differed between male and female patients, but did differ between patients originating at the site of injury and those transferred between hospitals. Fentanyl dose correlated poorly with the magnitude of pain relief (r = 0.22), but a dose greater than 2 microg/kg provided more relief than lower doses (5.1 +/- 2.1 vs 3.6 +/- 2.4, P < .02). CONCLUSION: Fentanyl analgesia from these critical care transport teams provided significant pain relief to trauma patients. Pain reduction was greater for patients who received more than 2.0 microg/kg of fentanyl.     

Renal replacement therapy in the critical care unit

Acute renal failure is common in critically ill patients. Many intensive care unit patients require renal replacement therapy (RRT). Hemodialysis can be performed as intermittent treatments or as continuous RRT, which can be customized to clinical goals by the use of carefully designed replacement fluids and hemodialysates. The available forms of RRT are reviewed, with emphasis on the clinical indications that contribute to the choice and design of therapy. Practical issues and troubleshooting are discussed, as are available options for anticoagulation during RRT. Consideration is given to modality choice, hemodynamic issues, costs, and physiologic outcomes.     

Antibiotic therapy of methicillin-resistant Staphylococcus aureus in critical care

The treatment of methicillin-resistant Staphylococcus aureus (MRSA) in the critically ill patient is challenging. Data for treatment of critically ill patients are often lacking because many such patients are excluded from industry-sponsored prospective randomized clinical trials. Infections due to MRSA are common in the critical care setting. Up to 24% of patients in intensive care units are colonized with MRSA, and 20% of all nosocomial bloodstream infections are due to MRSA. It is also one of the leading bacterial causes of ventilator- and hospital-acquired pneumonia. Vancomycin has been the drug of choice for treatment of MRSA in the critical care setting. Recent data showing vancomycin resistance, increasing numbers of MRSA isolates with higher vancomycin minumum inhibitory concentrations, and an apparent increase in vancomycin clinical failures have brought vancomycin's utility into question. A variety of treatment options for MRSA are available. Quinupristin-dalfopristin was the first alternative to vancomycin. However, its safety profile and potential for drug interactions limit its use. Linezolid has been shown to be effective in the treatment of pneumonia and skin and skin-structure infections due to MRSA. The drug's potential to cause bone marrow suppression limits its use, especially in treatment durations extending beyond 14 days. Daptomycin has been shown to be effective for the treatment of MRSA bloodstream and of MRSA skin and skin-structure infections. Tigecycline is the newest available drug with MRSA activity. It has demonstrated noninferiority to vancomycin in skin and skin-structure infections. However, its role in the treatment of ventilator- and hospital-acquired pneumonia is still unclear.     

Hemoadsorption in critical care.

This paper concerns the results of endotoxin hemoadsorption therapy using a PMX column in patients with perforative peritonitis complicated by multiple organ failure. The subjects were 31 patients aged 68 +/- 12 years. When systolic arterial pressure decreased to less than 90 mm Hg, endotoxin hemoadsorption was initiated and continued for 2 h. At the completion of endotoxin hemoadsorption, systolic arterial pressure, diastolic arterial pressure, and mean arterial pressure were significantly increased. Platelet count decreased to less than 50,000/mm(3) in 30% of patients. As for cytokines and vascular endothelial cell function markers, interleukin-6 and plasminogen activator inhibitor-1 significantly decreased. These results suggest favorable effects of endotoxin hemoadsorption on the hemodynamic and pathophysiological conditions in patients with septic shock although attention should be given to the decrease in platelet count.     

Nursing's role in complementary and alternative therapy use in critical care

Critical care nurses can expect to encounter more patients using CAT and increasing opportunities and requests for CAT use in their critical care environments. This provides an opportunity for nurses' involvement to shape proactively how the use of these therapies will unfold in critical care. This can be accomplished in various ways. Actively ask patients and families about use of CAT. Initiate discussions with colleagues and peers about professional and personal use of therapies. Explore the knowledge and education needed to administer specific CAT. Engage in research regarding the use of CAT in critical care. Identify experts in the institution and surrounding community. Encourage critical care units and institutions to consider how CAT should be implemented across the institution. From a broader perspective, nurses may become part of professional political processes shaping patient accessibility to CAT and the use of CAT in the discipline, across disciplines, and in healthcare settings and public domains. It is crucial that nurses not relinquish their role as traditional providers of CAT in providing safe, effective, and holistic care at the bedside of critically ill patients.     

Red cell transfusion therapy in the critical care setting

According to our own experience and published reports the frequency of red cell transfusion in intensive care units is in the range of 0.2 to 0.4 units per patient per day and is dependent upon the local strategy, the patients involved and the kind of surgery performed. The rationale for red cell transfusion is to maintain or restore the oxygen carrying capacity of the blood to avoid tissue hypoxia which occurs when oxygen delivery drops below a certain critical value. Besides bleeding, phlebotomy is also a significant source of blood loss in critically ill patients. According to several recent reviews and consensus articles there is no basis for a fixed indicator for transfusion, such as a haemoglobin concentration of < 100 gL-1. The decision to transfuse has to be made according to the patients individual status. The major adaptive mechanism in response to acute anaemia is an increase in cardiac output and hence blood flow to tissues. As a consequence even moderate degrees of acute anaemia may not be tolerated by patients with cardiac disease, whilst marked anaemia carries a considerable risk of ischaemia in patients with brain lesions or cerebral arterial stenoses. In critically ill patients it has been postulated that supply dependency of oxygen consumption occurs over a wide range of oxygen delivery, far above the critical values of oxygen delivery seen under normal conditions. Maximising oxygen delivery was therefore formulated as a goal in these patients. However, whether pathological supply dependency of oxygen delivery really exists in critically ill patients is still under discussion and recent studies found no benefit in maximising oxygen delivery to this patient group. However, individualised triggers for red blood cell transfusion are adequate for critically ill patients considering their co-morbidities and severity of disease. Finally, the decision to transfuse must also take into account the potential risks (infectious and non-infectious), as well as benefits for the individual patient. In the future, the level of transfusions may be reduced by using blood sparing techniques such as blood withdrawal in closed systems, bedside microchemistry, intravascular monitors, or autotransfusion of drainage blood in intensive care units.     

Current status of blood component therapy in surgical critical care

PURPOSE OF REVIEW: The use of blood component therapy, with transfusion of red cells, plasma, and platelets, is common in critical care. New evidence has emerged documenting the risks associated and lack of efficacy or improvement in clinical outcome with blood transfusion for the treatment of anemia in critically ill patients who are hemodynamically stable. RECENT FINDINGS: The safety of a restrictive transfusion strategy (transfuse only if hemoglobin < 7 g/dL) was reported in 1999. Despite compelling evidence from this prospective randomized clinical trial, clinicians have not substantially changed practice regarding blood transfusion in critical care. The recently published CRIT trial reported that the mean pre-transfusion hemoglobin was 8.6 g/dL in this large multicenter trial that examined transfusion practices in critical care in the US. Furthermore, only 19% of hospitals had an institutional blood transfusion protocol. The Surviving Sepsis Campaign guidelines have also recommended blood transfusion only when hemoglobin falls to 7.0 g/dL, following resolution of tissue hypoperfusion and in the absence of significant coronary artery disease or acute hemorrhage. We have an increased understanding of the pathophysiology of the anemia associated with critical care, related to the inflammatory response, downregulation of erythropoietin, and lack of iron availability due to macrophage sequestration. Clinical trials are underway to confirm the efficacy of recombinant erythropoietin in the treatment of critically ill patients with anemia. SUMMARY: Current data regarding blood transfusion thresholds and risks of blood transfusion have not as yet significantly altered practice patterns. Efforts to reduce blood transfusion rates in critically ill patients are required. These strategies will require education, unit and institutional protocols, and reduction of phlebotomy for diagnostic laboratory testing in the intensive care unit. Further investigations regarding anemia in critical care and new treatment and prevention strategies are required.