Exploring NT-proBNP, syndecan-1, and cytokines as biomarkers for transfusion-associated circulatory overload in a critically ill patient population receiving a single-unit red blood cell transfusion

BACKGROUND

Transfusion-associated circulatory overload (TACO) is an often underdiagnosed pulmonary transfusion complication. A biomarker could aid with the diagnosis. To date, B-type natriuretic peptide (BNP) and N-terminal prohormone B-type natriuretic peptide (NT-proBNP) seem the most promising biomarkers in the general hospital population. The aim was to evaluate NT-proBNP as a biomarker for TACO in a critically ill patient population and explore syndecan-1 and cytokines as other potential biomarkers.

STUDY DESIGN AND METHODS

A retrospective study was performed using samples and clinical data collected during a prospective observational study. Adult patients admitted to the intensive care and transfused with a single red blood cell unit were included. TACO cases were retrospectively identified using a case definition based on the current TACO definition. The primary biomarker was NT-proBNP, also we measured syndecan-1 IL-6, IL-8, and IL-10. All markers were measured directly before transfusion, 1 and 24 h after transfusion.

RESULTS

Our cohort included 64 patients, 12 of which were identified as TACO patients. TACO patients had a lower PaO2 /FiO2 ratio and were more often ventilated following transfusion compared to non-TACO patients. There was no significant difference in NT-proBNP between pre- and post-transfusion levels nor between TACO and non-TACO patients. Syndecan-1 was significantly elevated in TACO patients both pre- and post-transfusion compared to non-TACO patients.

DISCUSSION

NT-proBNP was not associated with TACO in this critically ill patient population. Interestingly, levels of syndecan-1 were increased in TACO patients at baseline. More research is needed to clarify this association and its possibilities as a biomarker to predict patients at risk for TACO.

The effect of plasma transfusion in an experimental two-hit animal model of transfusion-associated circulatory overload with heart failure

BACKGROUND

Transfusion-associated circulatory overload (TACO) is a leading cause of transfusion-related morbidity and mortality. TACO follows a two-hit pathophysiology, where comorbidities like cardiac or renal failure act as the first hit followed by blood transfusion as a second hit. Observational studies suggest that plasma transfusion is more likely to cause TACO than other blood products. We conducted a randomized animal study to gather evidence that plasma transfusion can induce TACO.

MATERIAL AND METHODS

As a first hit a large myocardial infarction was created in male Wistar rats. Then animals were randomized to receive 4 units of solvent/ detergent-treated pooled plasma (SDP), fresh frozen plasma (FFP), a colloid control (albumin 5%) or a crystalloid fluid control (Ringer's lactate) (n=10 per group). The primary outcome was the difference between pre- and post-transfusion left-ventricular end diastolic pressure (ΔLVEDP). Secondary outcomes were markers for acute lung injury; lung wet/dry weight ratio, PaO2/FiO2 ratio and pulmonary histological assessment.

RESULTS

Pre-transfusion characteristics were similar between groups. ΔLVEDP increased significantly after transfusion with SDP (7.7 mmHg; 4.5-10.5) and albumin (13.0 mmHg; 6.5-15.2), but not after FFP (7.9 mmHg, 1.1; 11.3) compared to infusion with Ringer's lactate (0.6 mmHg; 0.4-2.2), p=0.007, p=0.0005 and p=0.14 respectively. There were no significant differences in ΔLVEDP between groups receiving SDP, FFP or albumin. There was no increase in acute lung injury in any group compared to other groups.

DISCUSSION

Circulatory overload, measured as ΔLVEDP, was induced after transfusion of SDP or albumin, but not after infusion of Ringer's lactate. These results show that the effect of plasma transfusion on ΔLVEDP differs from fluid overload induced by crystalloid infusion. Colloid osmotic pressure may be an important component in the development of TACO and should be a target for future research.

Can volume-reduced plasma products prevent transfusion-associated circulatory overload in a two-hit animal model?

BACKGROUND AND OBJECTIVES

Transfusion-associated circulatory overload (TACO) is a pulmonary transfusion complication and a leading cause of transfusion-related morbidity and mortality. Volume overload and rising hydrostatic pressure as a consequence of transfusion are seen as the central pathway leading to TACO. A possible preventative measure for TACO could be the use of low-volume blood products like volume-reduced lyophilized plasma. We hypothesize that volume-reduced lyophilized plasma decreases circulatory overload leading to a reduced pulmonary capillary pressure and can therefore be an effective strategy to prevent TACO.

MATERIALS AND METHODS

A validated two-hit animal model in rats with heart failure was used. Animals were randomized to receive 4 units of either solvent-detergent pooled plasma (SDP) as control, standard volume lyophilized plasma (LP-S) or hyperoncotic volume-reduced lyophilized plasma (LP-VR). The primary outcome was the difference between pre-transfusion and post-transfusion left ventricular end-diastolic pressure (ΔLVEDP). Secondary outcomes included markers for acute lung injury.

RESULTS

LVEDP increased in all randomization groups following transfusion. The greatest elevation was seen in the group receiving LP-VR (+11.9 mmHg [5.9-15.6]), but there were no significant differences when compared to groups receiving either LP-S (+6.3 mmHg [2.9-13.4], p = 0.29) or SDP (+7.7 mmHg [4.5-10.5], p = 0.55). There were no significant differences in markers for acute lung injury, such as pulmonary wet/dry weight ratios, lung histopathology scores or PaO₂ /FiO₂ ratio between the three groups.

CONCLUSION

Transfusion with hyperoncotic volume-reduced plasma did not attenuate circulatory overload compared to standard volume plasma and was therefore not an effective preventative strategy for TACO in this rat model.

Incidence of transfusion-related acute lung injury temporally associated with solvent/detergent plasma use in the ICU: A retrospective before and after implementation study

Background

Transfusion‐related acute lung injury (TRALI) is a severe complication of plasma transfusion, though the use of solvent/detergent pooled plasma (SDP) has nearly eliminated reported TRALI cases. The goal of this study was to investigate the incidence of TRALI in intensive care units (ICU) following the replacement of quarantined fresh frozen plasma (qFFP) by SDP.

Study design and methods

A retrospective multicenter observational before–after cohort study was performed during two 6‐month periods, before (April–October 2014) and after the introduction of SDP (April–October 2015), accounting for a washout period. A full chart review was performed for patients who received ≥1 plasma units and developed hypoxemia within 24 h.

Results

During the study period, 8944 patients were admitted to the ICU. Exactly 1171 quarantine fresh frozen plasma (qFFP) units were transfused in 376 patients, and respectively, 2008 SDP units to 396 patients after implementation. Ten TRALI cases occurred during the qFFP and nine cases occurred during the SDP period, in which plasma was transfused. The incidence was 0.85% (CI95%: 0.33%–1.4%) per unit qFFP and 0.45% (CI95%: 0.21%–0.79%, p = 0.221) per SDP unit. One instance of TRALI occurred after a single SDP unit. Mortality was 70% for patients developing TRALI in the ICU compared with 22% in patients receiving at least one plasma transfusion.

Conclusion

Implementation of SDP lowered the incidence of TRALI in which plasma products were implicated, though not significantly. Clinically diagnosed TRALI can still occur following SDP transfusion. Developing TRALI in the ICU was associated with high mortality rates, therefore, clinicians should remain vigilant.

Prophylactic furosemide to prevent transfusion-associated circulatory overload: a randomized controlled study in rats

Transfusion-associated circulatory overload (TACO) is the leading cause of transfusion related morbidity and mortality. The only treatment is empirical use of furosemide. Our aim was to investigate if furosemide can prevent TACO. A randomized controlled trial was performed using a previously validated two-hit rat model for TACO. Volume incompliance was induced (first hit) in anemic, anesthetized Lewis rats. Rats were randomized to placebo, low-dose (5 mg kg-1) or high-dose (15 mg kg-1) furosemide-administered prior to transfusion (second-hit) and divided over two doses. Primary outcome was change in left-ventricular end-diastolic pressure (∆LVEDP) pre- compared to post-transfusion. Secondary outcomes included changes in preload, afterload, contractility and systemic vascular resistance, as well as pulmonary outcomes. Furosemide treated animals had a significantly lower ∆LVEDP compared to placebo (p = 0.041), a dose-response effect was observed. ∆LVEDP in placebo was median + 8.7 mmHg (IQR 5.9-11), + 3.9 (2.8-5.6) in the low-dose and 1.9 (- 0.6 to 5.6) in the high-dose group. The effect of furosemide became apparent after 15 min. While urine output was significantly higher in furosemide treated animals (p = 0.03), there were no significant changes in preload, afterload, contractility or systemic vascular resistance. Furosemide rapidly and dose-dependently decreases the rise in hydrostatic pulmonary pressure following transfusion, essential for preventing TACO.

Autologous red blood cell transfusion does not result in a more profound increase in pulmonary capillary wedge pressure compared to saline in critically ill patients: A randomized crossover trial

Background and Objectives

Transfusion‐associated circulatory overload (TACO) is a major cause of severe transfusion‐related morbidity. Transfusion of red blood cells (RBCs) has been shown to induce hydrostatic pressure overload. It is unclear which product‐specific factors contribute. We set out to determine the effect of autologous RBC transfusion versus saline on pulmonary capillary wedge pressure (PCWP) change.

Materials and Methods

In a randomized crossover trial, patients who had undergone coronary bypass surgery were allocated to treatment post‐operatively in the intensive care unit with either an initial 300 ml autologous RBC transfusion (salvaged during surgery) or 300 ml saline infusion first, followed by the other. Primary outcome was the difference in PCWP change. Secondary outcome measures were the difference in extra‐vascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI).

Results

Change in PCWP was not higher after autologous RBC transfusion compared to saline (ΔPCWP 0.3 ± 0.4 vs. 0.1 ± 0.4 mmHg). ΔEVLWI and ΔPVPI were significantly decreased after autologous RBC transfusion compared to saline (ΔEVLWI −1.6 ± 0.6 vs. 0.2 ± 0.4, p = 0.02; ΔPVPI −0.3 ± 0.1 vs. 0.0 ± 0.1, p = 0.01). Haemodynamic variables and colloid osmotic pressure were not different for autologous RBC transfusion versus saline.

Conclusion

Transfusion of autologous RBCs did not result in a more profound increase in PCWP compared to saline. RBC transfusion resulted in a decrease of EVLWI and PVPI compared to saline. Our data suggest that transfusing autologous RBCs may lead to less pulmonary oedema compared to saline. Future studies with allogeneic RBCs are needed to investigate other factors that may mediate the increase of PCWP, resulting in TACO.

Differential effects of speed and volume on transfusion-associated circulatory overload: A randomized study in rats

BACKGROUND AND OBJECTIVES

Transfusion-associated circulatory overload (TACO) is the primary cause of transfusion-related mortality. Speed and volume of transfusion are major risk factors. The aim of this study was to investigate the interaction of red blood cell (RBC) transfusion speed and volume on the development of TACO.

MATERIALS AND METHODS

A validated model for TACO in anaemic Lewis rats with an acute myocardial infarction was used. The effect on pulmonary hydrostatic pressure of one, two or four units of packed RBCs transfused in either 30 or 60 min was evaluated (3.3-26.6 ml·kg-1 ·hr-1 ). Pulmonary capillary pressure was measured as left ventricular end-diastolic pressure (LVEDP). Cardiac stress biomarkers atrial natriuretic-peptide (ANP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured 1-h post-transfusion.

RESULTS

Thirty animals were included (n = 5 per group). Transfusion of RBCs increased LVEDP in a volume-dependent manner (ΔLVEDP [mmHg]: -0.95, +0.50, +6.26, p < 0.001). Fast transfusion increased overall ΔLVEDP by +3.5 mmHg and up to +11.8 mmHg in the four units' group (p = 0.016). Doubling transfusion speed increased ΔLVEDP more than doubling volume in the larger volume groups. No difference in ANP or NT-proBNP were seen in high transfusion volume or groups.

CONCLUSION

Transfusion volume dose-dependently increased LVEDP, with speed of transfusion rapidly elevating LVEDP at higher transfusion volumes. ANP and NT-proBNP were not impacted by transfusion volume or speed in this model. TACO is seen as purely volume overload, however, this study emphasizes that limiting transfusion speed, as a modifiable risk factor, might aid in preventing TACO.

Reported transfusion-related acute lung injury associated with solvent/detergent plasma - A case series

Background

Antibody‐mediated transfusion‐related acute lung injury (TRALI) is caused by donor HLA or HNA antibodies in plasma‐containing products. In the Netherlands 55,000 units of solvent/detergent plasma (SDP), a pooled plasma product, are transfused yearly. It's produced by combining plasma from hundreds of donors, diluting harmful antibodies. Due to a lack of reported cases following implementation, some have labeled SDP as “TRALI safe”.

Study design and methods

Pulmonary transfusion reactions involving SDP reported to the Dutch national hemovigilance network in 2016–2019 were reviewed. Reporting hospitals were contacted for additional information, cases with TRALI and imputability definite, probable, or possible were included and informed consent was sought.

Results

A total of three TRALI and nine TACO cases were reported involving SDP. The imputability of one TRALI case was revised from possible to unlikely and excluded; in one case no informed consent was obtained. We present a case description of TRALI following SDP transfusion in a 69‐year‐old male, 3 days following endovascular aortic aneurysm repair. The patient received one unit of SDP to correct a heparin‐induced coagulopathy, prior to removal of a spinal catheter post‐operatively. Within five hours he developed hypoxemic respiratory failure requiring intubation, hypotension, bilateral chest infiltrates, and leucopenia. The patient made a full recovery.

Conclusion

This case of TRALI, following transfusion of a single unit of SDP to a patient without ARDS risk factors, demonstrates that TRALI can occur with this product. Clinicians should remain vigilant and continue to report suspected cases, to help further understanding of SDP‐associated TRALI.

Feasibility to estimate mean systemic filling pressure with inspiratory holds at the bedside

Background: A decade ago, it became possible to derive mean systemic filling pressure (MSFP) at the bedside using the inspiratory hold maneuver. MSFP has the potential to help guide hemodynamic care, but the estimation is not yet implemented in common clinical practice. In this study, we assessed the ability of MSFP, vascular compliance (Csys), and stressed volume (Vs) to track fluid boluses. Second, we assessed the feasibility of implementation of MSFP in the intensive care unit (ICU). Exploratory, a potential difference in MSFP response between colloids and crystalloids was assessed. Methods: This was a prospective cohort study in adult patients admitted to the ICU after cardiac surgery. The MSFP was determined using 3-4 inspiratory holds with incremental pressures (maximum 35 cm H₂O) to construct a venous return curve. Two fluid boluses were administered: 100 and 500 ml, enabling to calculate Vs and Csys. Patients were randomized to crystalloid or colloid fluid administration. Trained ICU consultants acted as study supervisors, and protocol deviations were recorded. Results: A total of 20 patients completed the trial. MSFP was able to track the 500 ml bolus (p < 0.001). In 16 patients (80%), Vs and Csys could be determined. Vs had a median of 2029 ml (IQR 1605-3164), and Csys had a median of 73 ml mmHg^-1 (IQR 56-133). A difference in response between crystalloids and colloids was present for the 100 ml fluid bolus (p = 0.019) and in a post hoc analysis, also for the 500 ml bolus (p = 0.010). Conclusion: MSFP can be measured at the bedside and provides insights into the hemodynamic status of a patient that are currently missing. The clinical feasibility of Vs and Csys was judged ambiguously based on the lack of required hemodynamic stability. Future studies should address the clinical obstacles found in this study, and less-invasive alternatives to determine MSFP should be further explored. Clinical Trial Registration: ClinicalTrials.gov Identifier NCT03139929.

The recipe for TACO: A narrative review on the pathophysiology and potential mitigation strategies of transfusion-associated circulatory overload

Transfusion associated circulatory overload (TACO) is one of the leading causes of transfusion related morbidity and mortality. TACO is the result of hydrostatic pulmonary edema following transfusion. However, up to 50% of all TACO cases appear after transfusion of a single unit, suggesting other factors, aside from volume, play a role in its pathophysiology. TACO follows a two-hit model, in which the first hit is an existing disease or comorbidity that renders patients volume incompliant, and the second hit is the transfusion. First hit factors include, amongst others, cardiac and renal failure. Blood product factors, setting TACO apart from crystalloid overload, include colloid osmotic pressure effects, viscosity, pro-inflammatory mediators and storage lesion byproducts. Differing hemodynamic changes, glycocalyx injury, endothelial damage and inflammatory reactions can all contribute to developing TACO. This narrative review explores pathophysiological mechanisms for TACO, discusses related therapeutic and preventative measures, and identifies areas of interest for future research.

Colloid osmotic pressure of contemporary and novel transfusion products

Background and Objectives

Colloid osmotic pressure (COP) is a principal determinant of intravascular fluid homeostasis and a pillar of fluid therapy and transfusion. Transfusion‐associated circulatory overload (TACO) is a leading complication of transfusion, and COP could be responsible for recruiting additional fluid. Study objective was to measure COP of blood products as well as investigate the effects of product concentration and storage lesion on COP.

Materials and Methods

Three units of each product were sampled longitudinally. COP was measured directly as well as the determinants thereof albumin and total protein. Conventional blood products, that is red blood cell (RBC), fresh‐frozen plasma (FFP) and platelet concentrates (PLTs), were compared with their concentrated counterparts: volume‐reduced RBCs, hyperconcentrated PLTs, and fully and partially reconstituted lyophilized plasma (prLP). Fresh and maximally stored products were measured to determine changes in protein and COP. We calculated potential volume load (PVL) to estimate volume recruited using albumin's water binding per product.

Results

Colloid osmotic pressure varies widely between conventional products (RBCs, 1·9; PLTs, 7·5; and FFP, 20·1 mmHg); however, all are hypooncotic compared with human plasma COP (25·4 mmHg). Storage lesion did not increase COP. Concentrating RBCs and PLTs did not increase COP; only prLP showed a supraphysiological COP of 47·3 mm Hg. The PVL of concentrated products was lower than conventional products.

Conclusion

Colloid osmotic pressure of conventional products was low. Therefore, third‐space fluid recruitment is an unlikely mechanism in TACO. Concentrated products had a lower calculated fluid load and may prevent TACO. Finally, storage did not significantly increase oncotic pressure of blood products.

Volume incompliance and transfusion are essential for transfusion-associated circulatory overload: a novel animal model

BACKGROUND

Transfusion‐associated circulatory overload (TACO) is the predominant complication of transfusion resulting in death. The pathophysiology is poorly understood, but inability to manage volume is associated with TACO, and observational data suggest it is different from simple cardiac overload due to fluids. We developed a two‐hit TACO animal model to assess the role of volume incompliance (“first‐hit”) and studied whether volume overload (“second‐hit”) by red blood cell (RBC) transfusion is different compared to fluids (Ringer's lactate [RL]).

MATERIALS AND METHODS

Male adult Lewis rats were stratified into a control group (no intervention) or a first hit: either myocardial infarction (MI) or acute kidney injury (AKI). Animals were randomized to a second hit of either RBC transfusion or an equal volume of RL. A clinically relevant difference was defined as an increase in left ventricular end‐diastolic pressure (ΔLVEDP) of +4.0 mm Hg between the RBC and RL groups.

RESULTS

In control animals (without first hit) LVEDP was not different between infusion groups (Δ + 1.6 mm Hg). LVEDP increased significantly more after RBCs compared to RL in animals with MI (Δ7.4 mm Hg) and AKI (Δ + 5.4 mm Hg), respectively. Volume‐incompliant rats matched clinical TACO criteria in 92% of transfused versus 25% of RL‐infused animals, with a greater increase in heart rate and significantly higher blood pressure.

CONCLUSION

To our knowledge, this is the first animal model for TACO, showing that a combination of volume incompliance and transfusion is essential for development of circulatory overload. This model allows for further testing of mechanistic factors as well as therapeutic approaches.

Transfusion-associated circulatory overload-a systematic review of diagnostic biomarkers

BACKGROUND

Transfusion‐associated circulatory overload (TACO) is the leading cause of transfusion‐related major morbidity and mortality. Diagnosing TACO is difficult because there are no pathognomonic signs and symptoms. TACO biomarkers may aid in diagnosis, decrease time to treatment, and differentiate from other causes of posttransfusion dyspnea such a transfusion‐related acute lung injury.

STUDY DESIGN AND METHODS

A systematic review of literature was performed in EMBASE, PubMed, the TRIP Database, and the Cochrane Library, from inception to June 2018. All articles discussing diagnostic markers for TACO were included. Non‐English articles or conference abstracts were excluded.

RESULTS

Twenty articles discussing biomarkers for TACO were included. The majority investigated B‐type natriuretic peptide (BNP) and the N‐terminal prohormone cleavage fragment of BNP (NT‐proBNP), markers of hydrostatic pressure that can be determined within 1 hour. The data indicate that a post/pretransfusion NT‐proBNP ratio > 1.5 can aid in the diagnosis of TACO. Posttransfusion levels of BNP less than 300 or NT‐proBNP less than 2000 pg/mL, drawn within 24 hours of the reaction, make TACO unlikely. Cut‐off levels that exclude TACO are currently unclear. In critically ill patients, the specificity of natriuretic peptides for circulatory overload is poor. Other biomarkers, such as cytokine profiles, cannot discriminate between TACO and transfusion‐related acute lung injury.

CONCLUSION

Currently, BNP and NT‐proBNP are the primary diagnostic biomarkers researched for TACO. An NT‐proBNP ratio greater than 1.5 is supportive of TACO, and low levels of BNP or NT‐proBNP can exclude TACO. However, they are unreliable in critically ill patients. Other biomarkers, including cytokines and pulmonary edema fluid‐to‐serum protein ratio have not yet been sufficiently investigated for clinical use.

Transfusion-associated circulatory overload: A survey among Dutch intensive care fellows

OBJECTIVES

Transfusion-associated circulatory overload (TACO) is a severe pulmonary transfusion reaction and leading cause of transfusion-related morbidity and mortality in Europe. TACO is of particular importance in critically ill patients, since they often receive blood transfusions and have multiple risk factors for TACO. This study investigates transfusion practices in patients at risk of developing TACO, and furthermore knowledge concerning risk factors, diagnoses and treatment strategies among Dutch intensive care unit (ICU) fellows.

MATERIAL AND METHODS

An unannounced paper-based survey was conducted among Dutch ICU fellows during an educational conference. The survey consisted of 16 multiple and open choice questions.

RESULTS

Of all 65 Dutch ICU fellows 56.8% completed the survey; of respondents 88.9% identified the correct constellation of symptoms for TACO. In total, 29.7% of the respondents are aware they are obligated to report TACO cases to the blood bank. Major risk factors for TACO that respondents identified were reduced left ventricular function, infusion volume and infusion rate. In a non-emergency setting, 45.9% of fellows start red blood cell transfusion with 2 units or more. Transfusion rates exceeded national guidelines in 15.4% of fictitious cases. TACO is treated with furosemide by 94.5% of the fellows, however goals of the therapy varied greatly.

CONCLUSION

Dutch ICU fellows are knowledgeable of TACO symptoms, risk factors and treatment, however knowledge on reporting and transfusion practice in the setting of at risk patients for TACO should be improved.

The practice of diagnosing and reporting transfusion-associated circulatory overload: a national survey among physicians and haemovigilance officers

OBJECTIVES

This study aims at identifying factors that disciplines consider when diagnosing and reporting transfusion-associated circulatory overload ('TACO').

BACKGROUND

TACO is a clinical diagnosis based mainly on subjective factors. Therefore, TACO could be an underreported complication of blood transfusion.

METHODS

A survey was conducted among critical care physicians, anaesthesiologists, haematologists, transfusion medicine physicians and haemovigilance officers using case vignettes and a questionnaire. Factors that may affect diagnosing TACO were investigated using conjoint analysis. A positive B-coefficient indicates a positive preference for diagnosing TACO. Participants rated factors influencing reporting TACO on a 0- to 100-point scale.

RESULTS

One hundred and seven surveys were returned (62%). Vignettes showed preferences in favour of diagnosing TACO with the onset of symptoms within 2 h [β 0·4(-0·1-1·0)], positive fluid balance [β 0·9(0·4-1·5)] and history of renal failure [β 0·6(0·1-1·2)]. Compared with transfusion of a single unit of red blood cells (RBC), respondents showed a preference for diagnosing TACO following a single unit of solvent/detergent (S/D) plasma or pooled platelet concentrate (PPC) [β 0·3(-0·2-0·7) resp. 0·5(-0·1-1·2)]. Multiple transfusion (6 RBC + 4 S/D plasma) was a strong preference for diagnosing TACO compared to 1 RBC and 1 S/D plasma [β 0·3(-0·8-1·3)]. Respondents did not fully take into account new hypertension and tachycardia when reporting TACO [median 70 (IQR 50-80) resp. 60 (IQR 50-80)]. No differences were observed between disciplines involved.

CONCLUSION

When diagnosing and reporting TACO, physicians and haemovigilance officers do consider known risk factors for TACO. Reporting could be improved by increasing the awareness of haemodynamic variables in future education programmes.

Balanced versus isotonic saline resuscitation-a systematic review and meta-analysis of randomized controlled trials in operation rooms and intensive care units

BACKGROUND

Fluid resuscitation is the cornerstone in treatment of shock, and intravenous fluid administration is the most frequent intervention in operation rooms and intensive care units (ICUs). The composition of fluids used for fluid resuscitation gained interest over the past decade, with recent focus on whether balanced solutions should be preferred over isotonic saline.

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs) comparing fluid resuscitation with a balanced solution versus isotonic saline in adult patients in operation room or ICUs. Primary outcome was in-hospital mortality, secondary outcomes included occurrence of acute kidney injury (AKI) and need for renal replacement therapy (RRT).

RESULTS

The search identified 11 RCTs involving 2,703 patients; 8 trials were conducted in operation room and 3 in ICU. In-hospital mortality, as well as the occurrence of AKI and need for RRT was not different between resuscitation with balanced solutions versus isotonic saline, neither in operation room nor in ICU patients. Serum chloride levels, but not arterial pH, were significantly lower in patients resuscitated with balanced solutions.

CONCLUSIONS

Currently evidence insufficiently supports the use of balanced over isotonic saline for fluid resuscitation to improve outcome of operation room and ICU patients.

Transfusion of 35-day-stored red blood cells does not alter lipopolysaccharide tolerance during human endotoxemia

BACKGROUND

Transfusion-related immunomodulation (TRIM) encompasses immunosuppressive and proinflammatory effects induced by red blood cell (RBC) transfusion. Changes that occur during storage in the RBC product have been hypothesized to underlie TRIM, mediated by tolerance of toll-like receptors (TLR). We investigated whether transfusion of 35-day-stored autologous RBCs alters cytokine production in response to stimulation with lipopolysaccharide (LPS) or lipotheic acid (LTA), in a clinically relevant model of endotoxemia.

STUDY DESIGN AND METHODS

Eighteen volunteers received 2 ng/kg LPS intravenously, followed by normal saline or 2- or 35-day-stored autologous RBC transfusion. Before LPS, before transfusion, and 6 hours after transfusion blood was collected to measure cytokine gene expression. Whole blood was used for ex vivo stimulation with LPS and LTA, after which cytokine levels were measured with enzyme-linked immunosorbent assay.

RESULTS

In vivo LPS induced a biphasic response in cytokine mRNA with peak values 2 hours after LPS infusion. Storage time of RBC transfusion did not influence cytokine mRNA levels. In vivo infusion of LPS resulted in tolerance for ex vivo stimulation with LPS and LTA. However, transfusion of either fresh or stored RBCs did not further affect the capacity to produce cytokines after ex vivo stimulation.

CONCLUSION

In a clinically relevant model of human endotoxemia, autologous transfusion of 35-day-stored RBCs does not influence cytokine mRNA levels nor does it change the capacity of white blood cells in whole blood to produce cytokines after ex vivo stimulation with LPS or LTA.

Adenoma detection rate varies greatly during colonoscopy training

BACKGROUND

The adenoma detection rate (ADR) is considered the most important quality indicator for colonoscopy and varies widely among colonoscopists. It is unknown whether the ADR of gastroenterology consultants can already be predicted during their colonoscopy training.

OBJECTIVE

To evaluate the ADR of fellows in gastroenterology and evaluate whether this predicts their ADR as gastroenterology consultants.

DESIGN

Retrospective observational study.

SETTING

Academic and regional centers.

PATIENTS

Symptomatic patients undergoing colonoscopy.

MAIN OUTCOME MEASUREMENTS

The variance in ADR among 7 gastroenterology fellows during their training (between May 2004 and March 2012) and of the same fellows after they registered as consultants (between October 2011 and April 2014) was evaluated. Multivariate logistic regression was performed to compare the highest detector (endoscopist with highest ADR) with the individual fellows and to evaluate whether an ADR of 20% or higher during the training was predictive of a high ADR as a consultant.

RESULTS

During training, ADRs ranged from 14% to 36% (P < .001). Compared with the highest detector, the OR for detecting an adenoma ranged from 0.64 (95% CI, 0.40-1.03) to 0.29 (95% CI, 0.17-0.48). After registration, ADR ranged from 19.8% to 40.2% (P = .066). Compared with the highest detector during consultancy, the OR ranged from 0.64 (95% CI, 0.34-1.21) to 0.26 (95% CI, 0.13-0.52). Only 2 fellows significantly improved their ADR after completing their training. An ADR lower than 20% during training was associated with a lower ADR as a consultant (OR 0.51; 95% CI, 0.30-0.87).

LIMITATIONS

Retrospective study.

CONCLUSIONS

Variance in ADR is already present during the endoscopy training of gastroenterology fellows. Most fellows do not improve their ADR after completing their training. These findings suggest that the ADR can be predicted during colonoscopy training, and we suggest that feedback and benchmarking should be implemented early during training of fellows in an effort to improve ADR in future daily practice as a consultant.