Pathophysiology of intensive care unit-acquired anemia

Effect of hematocrit, galactose and ascorbic acid on the blood glucose readings of three point-of-care glucometers

Glucometers are commonly used in a variety of healthcare settings and use in critically ill patients should not be assumed without appropriate tool validation. The study objective was to evaluate the accuracy of three point-of-care glucometers (POCGs) to assess glucose concentration in human blood sample. The POCGs tested included three different instruments and utilized three factors (hematocrit [Hct], galactose and ascorbic acid) in glucose measurements to determine the glucometers' accuracy and compared to the reference laboratory biochemical analyzer (Cobs 8000, Roche, Basal, Switzerland). In this study, the Nova StatStrip glucometer showed no significant variation compared to the laboratory method at high glucose level with various Hct%. ACCU-Chek Inform II overestimated the glucose results at Hct 22% and underestimated at Hct 62%. The Freestyle glucometer showed lower glucose levels compared to the Cobas 8000 at Hct 62%. The ACCU-Check showed significant increase of blood glucose with low Hct% levels when compared to the laboratory method. The Freestyle showed a decreased level of glucose with high Hct 62% interference compared to the Cobas 8000. Galactose interference 100 and 200 mg/dL dramatically affected the accuracy of ACCU-Chek Inform II. Nevertheless, among all three POCGs in this study, the Nova StatStrip showed the most reliable and stable results for glucose level in the presence of interference. Especially, those in critical care units, whereas the Freestyle Precision Pro and ACCU-Chek Inform II were insufficiently accurate for critically ill patients.

Combined Neutrophil-to-Lymphocyte Ratio and CURB-65 Score as an Accurate Predictor of Mortality for Community-Acquired Pneumonia in the Elderly

Purpose

Community-acquired pneumonia (CAP) is common among the elderly; it typically has a poor prognosis and high mortality. This study evaluated the factors predicting CAP-related in-hospital mortality in the elderly to identify a simpler and more accurate predictor.

Patients and Methods

This was a single-center, retrospective study. The data used in this study was collected from all older patients (≥65) with CAP admitted to our hospital between January 2012 and April 2020.

Results

A total of 2028 older patients with CAP were included; 121 (5.97%) died in hospital. Of the patients in the study, 1267 (62.5%) were men and 261 (12.9%) had a history of malignant tumors. After performing univariate and multivariate Cox regression analyses, sex, history of malignant tumor, CURB-65 score, neutrophil-to-lymphocyte ratio (NLR), hemoglobin level, and NLR*CURB-65 levels were associated with CAP mortality. By comparing the area under the receiver operating characteristic (ROC) curves of the predicted factors, the NLR*CURB-65 level used to predict CAP mortality in the elderly was 0.755, and was superior to other measurements. All included patients were then dichotomized into two groups based on NLR*CURB-65 level (≤9.06 and >9.06) according to the ROC analysis. Patients with a high NLR*CURB-65 level had higher in-hospital mortality than those with a low NLR*CURB-65 level. The two divided groups showed significant differences in age, sex, smoking history, comorbidity, and laboratory findings. This indicates that NLR*CURB-65 is a predictive index that could reflect the comprehensive condition of older patients with CAP.

Conclusion

NLR*CURB-65 is a simpler and more accurate predictor of CAP-related in-hospital mortality in the elderly.

Pathophysiology of perioperative anaemia

Perioperative anaemia is a common clinical entity. It is usually due to combination of various mechanisms, including: pre-existing anaemia prior to surgery; anaemia due to impaired erythropoiesis, including alterations of metabolism of iron and erythropoietin (EPO); anaemia due to increased destruction of red blood cells (RBCs); and anaemia due to iatrogenic causes. Postoperatively, anaemia resembles anaemia of chronic disease and is probably related to the effects of inflammatory mediators released during and after surgery on the production and survival of RBCs. Pro-inflammatory cytokines, such as tumour necrosis factor, impair erythropoietin-dependent signalling and iron homeostasis. Iatrogenic causes, notably excessive phlebotomies, remain a major cause of perioperative anaemia. With increasing emphasis on restrictive blood transfusion strategies, understanding these mechanisms is important for the clinician.

Effect of 6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride (Voluven®) on complications after subarachnoid hemorrhage: a retrospective analysis

Background

6% Hydroxyethyl Starch 130/0.4 in 0.9% Sodium Chloride (Voluven®; 6% HES 130/0.4) is a colloid often used for fluid resuscitation in patients with subarachnoid hemorrhage (SAH), despite a lack of safety data for this use. The purpose of our study was to evaluate the effect of 6% HES 130/0.4 on major complications associated with SAH.

Methods

Medical records of all patients presenting between May 2010 and September 2012 with aneurysmal SAH were analyzed. Patients were divided in two groups based on the administration of 6% HES 130/0.4; HES group (n=57) and Non-HES group (n=72). The primary outcome included a composite of three major complications associated with SAH: Delayed Cerebral Ischemia (DCI), Hydrocephalus (HCP) requiring cerebrospinal fluid (CSF) shunting, and Rebleeding.

Results

The study groups were similar with respect to most characteristics except the incidences of hypertension, ischemic heart disease, Fisher grade and lowest hemoglobin during stay. The odds of developing the primary composite outcome was higher in the HES group [OR= 3.1(1.30-7.36), p=0.01]. The patients in the HES group had a significantly longer median duration of hospital (19 vs 14 days) and Neurointensive Care Unit stay (14 vs 10 days) compared to the Non HES group.

Conclusion

We observed increased complications after SAH with 6% HES 130/0.4 (Voluven®) administration. An adequately powered prospective randomized controlled trial into the safety of 6% HES 130/0.4 in this patient population is warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-2-314) contains supplementary material, which is available to authorized users.

Hematology and Oncology in Critical Illness

This chapter will focus on a variety of hematologic issues pertinent to the care of critically ill children. This is an area of intense research with the pathophysiology underlying these clinical conditions becoming progressively better understood. This improved understanding has resulted in new therapeutic strategies that are being assessed in multicenter clinical trials. The chapter will begin by describing the incidence and pathophysiologic significance of anemia in the pediatric intensive care unit (PICU) providing a differential diagnosis of the many conditions that may present with anemia in this setting. The chapter will next consider disseminated intravascular coagulation (DIC) focusing on the pathophysiology of a condition that has been associated with much morbidity and mortality. The underlying conditions predisposing to DIC will be detailed as well as a number of treatment options that have been implemented in clinical trials. In addition to DIC, thrombocytopenia may be caused by a number of other clinical conditions important to the pediatric critical care provider. The clinical and prognostic significance of thrombocytopenia will be addressed and a focused differential diagnosis will be provided. Thrombotic disorders are becoming increasingly recognized in children and are a particular concern for the pediatric intensivist. The epidemiology of thromboembolism in children will be reviewed focusing on the conditions most commonly associated with these thromboses. Finally, a chapter on hematologic issues in the critically ill child would not be complete without a discussion of sickle cell disease. Acute chest syndrome, one of the most frequent complications of sickle cell disease resulting in the need for intensive care services, will be discussed in detail.

Transfusion in the critically ill: does it affect outcome?

Anemia and red blood cell (RBC) transfusions are common in critically ill and injured, trauma, and surgical patients. Tolerance of anemia is highly variable, depending on the presence of cardiovascular and other comorbid diseases that may diminish the hemodynamic response to a lower hemoglobin (Hb) level. The quest to define a minimum threshold Hb concentration at which patients achieve significant benefit to improve outcome has not yet been identified. Complications related to RBC transfusion are related to RBC storage and intrinsic properties of donor allogeneic RBCs, including bacterial contamination, transfusion-related acute lung injury, and transfusion-related immunomodulation. The best evidence related to transfusion-related outcome involves titrating transfusion requirements to parameters of severity of illness rather than arbitrarily defined Hb levels.

[Diagnostic blood losses in severe trauma patients]

OBJECTIVE

To analyze diagnostic (blood drawings) and iatrogenic (Continuous Renal Replacement Therapy, CRRT) blood losses (BL) in severe trauma patients.

METHOD

A one-year descriptive, prospective and observational study. We included patients over 15 years of age, admitted with severe trauma and who had a score of > or =16 on the Injury Severity Index (ISS). Those patients in whom limitation of therapeutic effort had been indicated were excluded. A total of 225 patients with 1619 days of evolution were analyzed for volume of BL/day/patient, type of diagnostic test, clinical outcome and utilization of CRRT. The variables were described as mean +/- standard deviation with the Student's T test.

RESULTS

Average blood loss of patient per day was 55.5+/-32.2 cc. Statistically significant differences were found between the blood volume drawn when the first day was compared to the second day, 73.5+/-32.2 vs. 56.3+/-21.9 (p<0.001); clinical outcome (alive vs death) 54.8+/-33 vs. 60.7+/-24.9 (p<0.05); severity (ISS<31 or > or =31) 54.65+/-20 vs. 61.5+/-28.5 (p<0.001), No RRT vs RRT: 50.9+/-18.9 vs. 97.2+/-72.6 (p<0.001).

CONCLUSIONS

The greatest diagnostic BL occurs during the resuscitation phase, in the patients who die, in those with greater severity and those undergoing CRRT.

The prevalence of anemia and its association with 90-day mortality in hospitalized community-acquired pneumonia

Background

The prevalence of anemia in the intensive care unit is well-described. Less is known, however, of the prevalence of anemia in hospitalized patients with lesser illness severity or without organ dysfunction. Community-acquired pneumonia (CAP) is one of the most frequent reasons for hospitalization in the United States (US), affecting both healthy patients and those with comorbid illness, and is typically not associated with acute blood loss. Our objective was to examine the development and progression of anemia and its association with 90d mortality in 1893 subjects with CAP presenting to the emergency departments of 28 US academic and community hospitals.

Methods

We utilized hemoglobin values obtained for clinical purposes, classifying subjects into categories consisting of no anemia (hemoglobin >13 g/dL), at least borderline (≤ 13 g/dL), at least mild (≤ 12 g/dL), at least moderate (≤ 10 g/dL), and severe (≤ 8 g/dL) anemia. We stratified our results by gender, comorbidity, ICU admission, and development of severe sepsis. We used multivariable logistic regression to determine factors independently associated with the development of moderate to severe anemia and to examine the relationship between anemia and 90d mortality.

Results

A total of 8240 daily hemoglobin values were measured in 1893 subjects. Mean (SD) number of hemoglobin values per patient was 4.4 (4.0). One in three subjects (33.9%) had at least mild anemia at presentation, 3 in 5 (62.1%) were anemic at some point during their hospital stay, and 1 in 2 (54.5%) survivors were discharged from the hospital anemic. Anemia increased with illness severity and was more common in those with comorbid illnesses, female gender, and poor outcomes. Yet, even among men and in those with no comorbidity or only mild illness, anemia during hospitalization was common (~55% of subjects). When anemia was moderate to severe (≤ 10 g/dL), its development was independently associated with increased 90d mortality, even among hospital survivors.

Conclusions

Anemia was common in hospitalized CAP and independently associated with 90d mortality when hemoglobin values were 10 g/dL or less. Whether prevention or treatment of CAP-associated anemia would improve clinical outcomes remains to be seen.

Factors associated with the development of anemia after subarachnoid hemorrhage

INTRODUCTION

Anemia is common after subarachnoid hemorrhage (SAH) and may exacerbate the reduction in oxygen delivery that underlies delayed cerebral ischemia. Fall in hemoglobin may relate to blood loss as well as inflammatory suppression of erythropoiesis. Identifying factors associated with anemia may facilitate targeted interventions, such as the use of erythropoiesis-stimulating agents, which could minimize the burden of anemia and reduce red blood cell (RBC) transfusion requirements.

METHODS

We analyzed a cohort of patients with spontaneous SAH admitted over a 3-year period who survived at least 4 days. All patients had daily hematocrit values drawn while in the ICU. Multivariate regression was performed to determine baseline and early post-admission variables associated with development of anemia (defined as hematocrit < 30%).

RESULTS

Anemia developed in 47% of 243 patients with SAH after a mean of 3.5 days (median 2 days). Admission variables independently associated with anemia were female gender (OR 3.7, 95% CI 1.8-7.6), baseline hematocrit < 36% (OR 3.9, 1.5-10.1 compared to 36-45%), history of hypertension (OR 2.1, 1.05-4.2), and poor clinical grade (OR 5.9, 2.3-15.0). Surgical aneurysm treatment (OR 13.5, 6.0-30.3) and greater admission SIRS score (OR 5.7, 1.7-19.2 if 3-4 criteria for systemic inflammatory response syndrome were met on day of admission compared to none) were also associated with fall in hematocrit.

CONCLUSIONS

It may be possible to predict those most likely to develop anemia using simple baseline clinical variables. Anemia was strongly related to surgery, likely through greater blood loss, and greater systemic inflammatory response on admission, possibly explained by cytokine-mediated inhibition of RBC production.

Alternatives to blood transfusion

Blood transfusion therapy in the 21st century continues to present limitations regarding efficacy and risks. Blood management partners optimal blood transfusion therapy with anemia management that incorporates nonblood strategies and techniques. A planned approach to anemia prevention, identification, and treatment can reduce the need for blood transfusion and improve patient outcomes. The use of pharmaceutical agents and tools to minimize blood loss also leads to blood transfusion reduction. Nurses play an integral role in affecting the use of alternatives to blood transfusion. Through assessment, communication, and an understanding of blood management strategies, nurses are patients' front-line innovators in promoting best practices.