Blood tranfusion in critically ill patients: state of the art

Related Factors of Anemia in Critically Ill Patients: A Prospective Multicenter Study

Anemia is common in critically ill patients; almost 95% of patients admitted to intensive care units (ICUs) have hemoglobin levels below normal. Several causes may explain this phenomenon as well as the tendency to transfuse patients without adequate cause: due to a lack of adherence to protocols, lack of supervision, incomplete transfusion request forms, or a lack of knowledge about the indications, risks, and costs of transfusions. Daily sampling to monitor the coagulation parameters and the acid-base balance can aggravate anemia as the main iatrogenic factor in its production. We studied the association and importance of iatrogenic blood loss and other factors in the incidence of anemia in ICUs. We performed a prospective, observational, multicenter study in five Spanish hospitals. A total of 142 patients with a median age of 58 years (IQI: 48-69), 71.83% male and 28.17% female, were admitted to ICUs without a diagnosis of iatrogenic anemia. During their ICU stay, anemia appeared in 66.90% of the sample, 95 patients, (95% CI: 58.51-74.56%). Risk factors associated with the occurrence of iatrogenic anemia were arterial catheter insertion (72.63% vs. 46.81%, p-value = 0.003), venous catheter insertion (87.37% vs. 72.34%, p-value = 0.023), drainages (33.68% vs. 12. 77%, p-value = 0.038), and ICU stay, where the longer the stay, the higher the rate of iatrogenic anemia (p-value < 0.001). We concluded that there was a statistical significance in the production of iatrogenic anemia due to the daily sampling for laboratory monitoring and critical procedures in intensive care units. The implementation of patient blood management programs could address these issues.

Dosing of thromboprophylaxis and mortality in critically ill COVID-19 patients

Background

A substantial proportion of critically ill COVID-19 patients develop thromboembolic complications, but it is unclear whether higher doses of thromboprophylaxis are associated with lower mortality rates. The purpose of the study was to evaluate the association between initial dosing strategy of thromboprophylaxis in critically ill COVID-19 patients and the risk of death, thromboembolism, and bleeding.

Method

In this retrospective study, all critically ill COVID-19 patients admitted to two intensive care units in March and April 2020 were eligible. Patients were categorized into three groups according to initial daily dose of thromboprophylaxis: low (2500–4500 IU tinzaparin or 2500–5000 IU dalteparin), medium (> 4500 IU but < 175 IU/kilogram, kg, of body weight tinzaparin or > 5000 IU but < 200 IU/kg of body weight dalteparin), and high dose (≥ 175 IU/kg of body weight tinzaparin or ≥ 200 IU/kg of body weight dalteparin). Thromboprophylaxis dosage was based on local standardized recommendations, not on degree of critical illness or risk of thrombosis. Cox proportional hazards regression was used to estimate hazard ratios with corresponding 95% confidence intervals of death within 28 days from ICU admission. Multivariable models were adjusted for sex, age, body mass index, Simplified Acute Physiology Score III, invasive respiratory support, and initial dosing strategy of thromboprophylaxis.

Results

A total of 152 patients were included: 67 received low-, 48 medium-, and 37 high-dose thromboprophylaxis. Baseline characteristics did not differ between groups. For patients who received high-dose prophylaxis, mortality was lower (13.5%) compared to those who received medium dose (25.0%) or low dose (38.8%), p = 0.02. The hazard ratio of death was 0.33 (95% confidence intervals 0.13–0.87) among those who received high dose, and 0.88 (95% confidence intervals 0.43–1.83) among those who received medium dose, as compared to those who received low-dose thromboprophylaxis. There were fewer thromboembolic events in the high (2.7%) vs medium (18.8%) and low-dose thromboprophylaxis (17.9%) groups, p = 0.04.

Conclusions

Among critically ill COVID-19 patients with respiratory failure, high-dose thromboprophylaxis was associated with a lower risk of death and a lower cumulative incidence of thromboembolic events compared with lower doses.

Trial registration

Clinicaltrials.gov NCT04412304 June 2, 2020, retrospectively registered.

Blood volume extracted from the critical patient in the first 24 hours after admission

OBJECTIVE

To calculate the number of analytical tests and blood volume drawn during the first 24hours of admission to the Intensive Care Unit (ICU). To analyse values of basal haemoglobin and at 24hours, relate them to blood loss, weight variation, and scoring system.

METHOD

An observational descriptive pilot study. Variables studied: age, sex, diagnosis on admission, analytical tests extracted, waste quantity before the extraction of samples, total volume blood extracted in 24hours, weight variation, APACHE, SAPS, basal haemoglobin and at 24hours. Statistical analysis with SPSS vs 20.0. Variables correlation sex, weight variation, the number of analytical tests and haemoglobin change.

RESULTS

The study included 100 patients. The average number of extractions per patient/day was 7.2 (±2.6). The average waste quantity was 32.61ml (±15.8). The blood volume used for determinations was 48.18ml / 24h (±16.74). The haemoglobin value decreased in the first 24hours of admission, being higher in men (P<.05). The scoring systems were statistically significant for levels of haemoglobin (Hb1 -0.3; P=.001; Hb2 -0.4; P=.001).

CONCLUSIONS

Of the total volume of blood extracted in ICU, 40% belongs to a volume of waste and 60% of blood is used for analytical tests. There is a decrease in haemoglobin exists 24hours after admission of the critical patient. Statistically, it has not been possible to demonstrate its relation with the number of analytical tests.

Risk Factors for Intensive Care Unit Admission in Patients with Autoimmune Encephalitis

Background

Prevention and early recognition of critical illness in patients with autoimmune encephalitis (AE) is essential to achieve better outcome.

Aim of the study

To evaluate risk factors for intensive care unit (ICU) admission and its prognostic impact in patients with AE.

Patients and methods

A reclassification of patients hospitalized between 2011 and 2016 revealed 17 “definite” and 15 “probable” AE cases. Thirteen patients (41%) developed critical illness and required ICU admission. The underlying conditions were intractable seizures or status epilepticus (54%), altered mental state (39%), and respiratory failure (8%).

Results

ICU admission was associated with longer time from first symptoms to hospitalization (p = 0.046). Regression analysis revealed that anemia on hospital admission and definite diagnosis of AE was associated with a higher risk of acquiring critical illness. At last follow-up after a median of 31 months (range 2.5–52.4), seven patients had died (23%) and 63% had a good outcome [modified Rankin Scale (mRS) 0–3]. Anemia was associated with poor prognosis (p = 0.021), whereas development of critical illness did not impact mortality and functional outcome.

Conclusion

We confirmed the need for ICU care in a subgroup of patients and the prevailing objective is improved seizure control, and definite diagnosis of AE and anemia were identified as risk factors for development of critical illness. However, prognosis was not affected by ICU admission.

Anemia in Intensive Care: A Review of Current Concepts

Anemia in patients admitted to an intensive care unit is common and affects almost all critically ill patients. The intensivist is faced with the challenge of treating multifactorial etiologies, mainly bleeding and blood loss due to phlebotomy and decreased erythropoiesis. Red cell transfusion, the most common treatment for anemia, comes with associated risks, which may further reduce the chance of survival of these patients. The best evidence suggests the practice of restrictive RBC transfusion (transfusion at Hb<7 g/dl). In this article, the etiopathogenesis of the anemia in critically ill is reviewed, and current opinion on the pros and cons of various management strategies are discussed with emphasize on restrictive transfusion policy.

In vitro and in vivo validation of stored swine erythrocyte viability to establish an experimental model of homologous red blood cell transfusion: a pilot study

Objective

To develop experimental models of erythrocyte transfusion, the first step is to ensure the viability of the red blood cells transfused. In this pilot study, we assessed the viability of transfused red blood cells with validation in vitro and in vivo of homologous swine erythrocytes stored for 14 days.

Methods

Blood collected from one Agroceres^® swine was stored in two red blood cell units. In vivo validation was performed by labeling the red blood cells with Na₂⁵¹CrO₄ and recovering the viable erythrocytes after 24 hours of infusion in one autologous and four homologous animals. In vitro validation was performed at baseline and after 14 days in sixteen red blood cell units by measuring hemoglobin, hematocrit, hemolysis index and free hemoglobin. A post-mortem splenectomy was performed to evaluate the splenic sequestration of erythrocytes, and the radioactivity of the supernatant samples was counted to evaluate intravascular hemolysis.

Results

After 14 days of storage, the red blood cell units had lower volumes and equivalent total concentrations of hemoglobin and hematocrit compared to human standards. The free hemoglobin concentration increased from 31.0±9.3 to 112.4±31.4mg/dL (p<0.001), and the hemolysis index increased from 0.1±0.1 to 0.5±0.1% (p<0.001). However, these tests were within the acceptable range for human standards. The percentage of radioactivity in supernatant samples was similar at baseline and after 24 hours, thus excluding significant hemolysis. No evidence of splenic sequestration of radioactive erythrocytes was found.

Conclusion

Swine red blood cells stored for 14 days are viable and can be used in experimental studies of transfusion. These validation experiments are important to aid investigators in establishing experimental models of transfusion.

Total knee arthroplasty: indication of blood transfusion according to hematimetric variation and clinical symptoms of hypoperfusion

OBJECTIVE

To analyze the relationship between hematimetric variation and the presence of clinical symptoms of hypoperfusion for indicating blood transfusion in patients undergoing total knee arthroplasty.

METHODS

A retrospective analysis was conducted on data gathered from the medical files of 55 patients with a diagnosis of gonarthrosis, who underwent total knee arthroplasty at a hospital orthopedics and traumatology service between February 2011 and December 2012. The patients studied presented unilateral joint degeneration and fitted into the indications for surgical treatment. All the patients underwent a preoperative cardiological evaluation, presenting a pattern of ASA I-III and absence of blood dyscrasia, and preoperative hemoglobin measurements were made. However, no minimum hematimetric value was established for the surgical treatment; there were only clinical criteria for blood perfusion.

RESULTS

Among the 55 patients, 35 were female and 20 were male, and the mean age was 68 years. Six patients underwent homologous blood transfusion, because of their clinical condition of tissue hypoperfusion, persistent hypotension, loss of consciousness, sweating and coercible vomiting. They presented postoperative hemoglobin of 7.5-8.8 g/dL.

CONCLUSION

For patients with falls in hemoglobin counts greater than 20% and values lower than 9 g/dL after the surgery, there is a possible need for blood transfusion, which should only be indicated when accompanied by major symptoms of tissue hypoperfusion.

Critical evaluation of justifications for the transfusion of red blood cells: the reality of a government emergency hospital

BACKGROUND

Blood products and derivatives are indispensable resources in medical therapies. However, it is important to note that the number of donations is far from ideal. Despite constant campaign efforts, a deficit of 1 million units is expected by 2030.

OBJECTIVES

To determine the adequacy of the indications for red blood cell transfusion in an emergency hospital in Alagoas.

METHODS

This was a cross-sectional observational study conducted at the Alagoas Blood Center. Of a total of 2936 red blood cell transfusion requests in 2009, 334 were randomized and compared with transfusion parameters described in the literature (primary variable). After analysis, the transfusion requests were categorized as adequate, inadequate or inconclusive. This last group included all red blood cell transfusion requests with insufficient clinical information, rendering their classification as adequate or inadequate impossible. The secondary variable involved the reasons for red blood cell transfusion. A 95% confidence interval was used in the statistical analysis.

RESULTS

Forty-seven (14.07%) requests were adequate and 30 (8.98%) were inadequate. Most of the requests were classified as inconclusive (76.94%). The main indications for transfusion were upper gastrointestinal bleeding (26.95%), anemia (46.71%), hypovolemia/hypovolemic shock (10.78%) and sepsis/septic shock (3.29%).

CONCLUSION

It was not possible to reach a conclusion on the adequacy of the indication for transfusion in most of the cases. Therefore, it is important to adopt a transfusion protocol, rigorously analyze blood bank requests, to provide awareness campaigns on the rational use of blood and to implement strategies to use blood products more effectively.

Blood transfusion utilization and recipient survival at Hospital das Clinicas in São Paulo, Brazil

BACKGROUND

The characteristics of blood recipients including diagnoses associated with transfusion and posttransfusion survival are unreported in Brazil. The goals of this analysis were: 1) to describe blood utilization according to clinical diagnoses and patient characteristics and 2) to determine the factors associated with survival of blood recipients.

STUDY DESIGN AND METHODS

A retrospective cross-sectional analysis was conducted on all inpatients in 2004. Data came from three sources: The first two files consist of data about patient characteristics, clinical diagnosis, and transfusion. Analyses comparing transfused and nontransfused patients were conducted. The third file was used to determine survival recipients up to 3 years after transfusion. Logistic regression was conducted among transfused patients to examine characteristics associated with survival.

RESULTS

In 2004, a total of 30,779 patients were admitted, with 3835 (12.4%) transfused. These patients had 10,479 transfusions episodes, consisting of 39,561 transfused components: 16,748 (42%) red blood cells, 15,828 (40%) platelets (PLTs), and 6190 (16%) plasma. The median number of components transfused was three (range, 1-656) per patient admission. Mortality during hospitalization was different for patients whose admissions included transfusion or not (24% vs. 4%). After 1 year, 56% of transfusion recipients were alive. The multivariable model of factors associated with mortality after transfusion showed that the most significant factors in descending order were hospital ward, increasing age, increasing number of components transfused, and type of components received.

CONCLUSION

Ward and transfusion are markers of underlying medical conditions and are associated with the probability of survival. PLT transfusions are common and likely reflect the types of patients treated. This comprehensive blood utilization study, the first of its kind in Brazil, can help in developing transfusion policy analyses in South America.

Avaliação da perda sanguínea na artroplastia total do joelho com e sem soltura do torniquete

OBJETIVO: Avaliar a perda sanguínea em pacientes submetidos à artroplastia total cimentada do joelho com e sem soltura trans-operatória do torniquete pneumático para a hemostasia. MÉTODOS: Foram estudados 72 pacientes submetidos à artroplastia total, num total de 80 joelhos, divididos em dois grupos: Grupo 1 onde se manteve o torniquete pneumático até a sutura e curativo da ferida operatória, e Grupo 2 onde foi realizada a soltura do torniquete pneumático após a cimentação da prótese, com realização de hemostasia direta, antes da sutura e curativo. Os pacientes foram avaliados quanto ao sangramento pelo dreno de sucção e à contagem de hemoglobina e hematócrito, considerando os intervalos de duas, 24 e 48 horas de pós-operatório. RESULTADOS: Não houve diferença significante entre os dois grupos quanto ao sangramento pós-operatório e decréscimo dos parâmetros hematimétricos. Somente um paciente do Grupo 2 necessitou transfusão de concentrado de hemáceas no pós-operatório. CONCLUSÃO: O sangramento pós-operatório na ATJ mostrou-se igual com e sem a soltura do torniquete pneumático para a realização da hemostasia.

Red blood cell transfusion threshold in postsurgical pediatric intensive care patients: a randomized clinical trial

BACKGROUND

The optimal transfusion threshold after surgery in children is unknown. We analyzed the general surgery subgroup of the TRIPICU (Transfusion Requirements in Pediatric Intensive Care Units) study to determine the impact of a restrictive versus a liberal transfusion strategy on new or progressive multiple organ dysfunction syndrome (MODS).

METHODS

The TRIPICU study, a prospective randomized controlled trial conducted in 17 centers, enrolled a total of 648 critically ill children with a hemoglobin equal to or below 9.5 g/dL within 7 days of pediatric intensive care unit (PICU) admission to receive prestorage leukocyte-reduced red-cell transfusion if their hemoglobin dropped below either 7.0 g/dL (restrictive) or 9.5 g/dL (liberal). A subgroup of 124 postoperative patients (60 randomized to restrictive and 64 to the liberal group) were analyzed. This study was registered at http://www.controlled-trials.com and carries the following ID ISRCTN37246456.

RESULTS

Participants in the restrictive and liberal groups were similar at randomization in age (restrictive vs. liberal: 53.5 +/- 51.8 vs. 73.7 +/- 61.8 months), severity of illness (pediatric risk of mortality [PRISM] score: 3.5 +/- 4.0 vs. 4.4 +/- 4.0), MODS (35% vs. 29%), need for mechanical ventilation (77% vs. 74%), and hemoglobin level (7.7 +/- 1.1 vs. 7.9 +/- 1.0 g/dL). The mean hemoglobin level remained 2.3 g/dL lower in the restrictive group after randomization. No significant differences were found for new or progressive MODS (8% vs. 9%; P = 0.83) or for 28-day mortality (2% vs. 2%; P = 0.96) in the restrictive versus liberal group. However, there was a statistically significant difference between groups for PICU length of stay (7.7 +/- 6.6 days for the restrictive group vs. 11.6 +/- 10.2 days for the liberal group; P = 0.03).

CONCLUSIONS

In this subgroup analysis of pediatric general surgery patients, we found no conclusive evidence that a restrictive red-cell transfusion strategy, as compared with a liberal one, increased the rate of new or progressive MODS or mortality.

[Results of a national survey on transfusion practice in Intensive Care Units]

INTRODUCTION

Blood derivatives are clinical products that are currently used, for which their lack of availability, clinical relevance and presence of associated side effect that make it necessary to known and evaluate their utility rigorously are characteristic.

OBJECTIVE

To analyze knowledge of attitudes, knowledge and behavior on transfusional policy in the different Spanish Intensive Care Units (ICU).

DESIGN

A mail-based survey (electronic and conventional) in the ICUs.

DURATION

The study was planned in 2005 and conducted during the year 2006.

SETTING

Spanish ICUs.

PATIENTS AND METHOD

A 27-question questionnaire.

RESULTS

Most are middle-sized ICUs (10-20 beds), with predominantly medical activities. The staff member, alone or with the resident, generally decides the transfusion based on his/her experience, although with a tendency to follow the scientific guidelines. Generally, there is no transfusional committee. When red blood packs are transfused, generally between 2 to 4 units are used. The hemoglobin value is orientative, although the decision is clear if < 7 g/dl (10 g/dl if there is heart disease). Drug alternatives to transfusion are not generally used due to lack of evidence and price. In 50% of cases, the association between transfusion and increase in mortality is considered to be certain.

CONCLUSIONS

Strong consideration must be made about transfusion and its over use should be avoided. For this purpose, educational guidelines and consensus meetings are necessary to establish recommendations on the use of blood products and their pharmacological alternatives.