Acid-base, electrolyte and metabolite concentrations in packed red blood cells for major transfusion in infants

Acid-base and electrolyte changes in dogs after packed red blood cell transfusion

BACKGROUND

Packed RBC (pRBC) transfusions are often necessary to enhance organ perfusion and tissue oxygenation in cases of severe anemia.

OBJECTIVES

We aimed to describe changes in acid-base and biochemical parameters in dogs after transfusion of pRBC and potential effects on the outcome.

METHODS

The prospective observational study included anemic dogs requiring pRBC transfusions. Venous blood gas and electrolytes were measured pre-transfusion and repeated within 1 h post-transfusion. Signalment, pre-existing conditions and underlying disease(s), number of days spent of hospitalization, the quantity of transfused pRBC units, and the outcome were also recorded. Associations between analytical values and all other parameters before and after transfusion were assessed using the Wilcoxon test. A generalized linear model was generated for each of the blood gas parameters post-transfusion, including the pre-transfusion values and the characteristics of the animal as fixed effects. The effect of the blood gas parameters on the mortality and hospitalization length was assessed using logistic regression and generalized linear models, respectively.

RESULTS

Twenty-six dogs with different causes of anemia were included in the study, with dogs remaining hospitalized for a median of 3 days (range: 0-11). Pre-transfusion heart rate, respiratory rate, Angap, base excess, and lactate were higher than post-transfusion values. Post-transfusion results showed an increase in hematocrit, hemoglobin, HCO3-, PCO2, tCO2, and chloride. Pre-transfusion hypophosphatemia and receiving an increased volume of transfused pRBC were associated with a longer hospital stay, while higher pre-transfusion lactate values were associated with higher mortality.

CONCLUSIONS

pRBC transfusion in anemic dogs was associated with an improvement in perfusion and acid-base parameters. Pre-transfusion lactate may be an indicator of mortality in dogs.

[Improved quality of stored packed red blood cells by mechanical rinsing]

BACKGROUND

The transfusion of packed red blood cells (PRBC) is associated with various side effects, including storage damage to PRBCs. The cells change their structure, releasing potassium as well as lactate. Mechanical rinsing, available in many hospitals, is able to remove toxic substances and possibly minimizes the negative side effects of transfusion.

OBJECTIVE

The primary aim of our study was to improve the quality of PRBCs before transfusion. The effects of different washing solutions on PRBC quality were analyzed.

MATERIAL AND METHODS

This in vitro study compares 30 mechanically washed PRBCs. They were either processed with standard normal saline 0.9% (n = 15, N group) or a hemofiltration solution containing 4 mmol/l potassium (n = 15, HF group) by a mechanical rinsing device (Xtra, LivaNova, Munich, Germany). A subgroup analysis was performed based on the storage duration of the processed PRBCs (7, 14, 37 days). Samples were taken before washing (EKprä), immediately after washing (EKpost) and 10 h later (EKpost10h), after storage in the "wash medium" at room temperature. Concentrations of ATP (probability of survival in transfused erythrocytes), lactate, citrate and electrolytes (potassium, sodium, chloride, calcium) were tested.

RESULTS AND CONCLUSION

Mechanical rinsing improves pretransfusion quality of PRBC. Washing with a hemofiltration solution results in a more physiological electrolyte composition. Even 10 h after mechanical rinsing with a hemofiltration solution, the quality of 37-day-old PRBC is comparable to young PRBC that have been stored for 7 days and have not been washed. Washing stored PRBC increases the ATP content, which subsequently leads to an increased probability of survival of red cells after transfusion.

ECMO for paediatric cardiac arrest caused by bronchial rupture and severe lung injury: a case report about life-threatening rescue at an adult ECMO centre

BACKGROUND

Bronchial rupture in children is a rare but dangerous complication after chest trauma and is associated with increased mortality. Veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) is reported as one of the treatments for this life-threatening complication.

CASE PRESENTATION

A 4-year-old boy with bronchial rupture and traumatic wet lung complicated by cardiac arrest after chest trauma was admitted to an adult ECMO centre. He experienced two cardiac arrests, one before and one during the operation. The total duration of cardiac arrest was 30 min. V-V ECMO was initiated because of severe hypoxia and hypercapnia during the operation. ECMO was performed for 6 days, and mechanical ventilation lasted 11 days. On the 31st day after surgery, he had recovered completely and was discharged without neurological deficit.

CONCLUSION

V-V ECMO can be considered for supportive care in children with severe acute respiratory failure after bronchial rupture. In an emergency, V-V ECMO can be carried out effectively in a qualified and experienced adult ECMO centre. However, the application of ECMO in children is different from that in adults and requires more refined management.

The Acute Effect of Packed Red Blood Cell Transfusion in Mechanically Ventilated Children after the Norwood Operation

Packed red blood cell (PRBC) transfusions are commonly administered in pediatric patients following the Norwood operation. This study was conducted to determine the effect of PRBC transfusions on hemodynamic parameters in pediatric patients with single-ventricle physiology and parallel circulation. A single-center, retrospective chart review was conducted. Pediatric patients admitted to the cardiac intensive care unit after Norwood operation between 2017 and 2018 were identified. Hemodynamic parameters were collected within a four-hour period before and after a PRBC transfusion. Univariate analyses using paired t tests were conducted to compare blood gas values before and after PRBC transfusion. Next, multivariate regression analyses were conducted to model the impact of transfusion volume, change in hemoglobin levels, and change in FiO2 on the change in PaO2 and PaCO2. These analyses included data from 33 eligible patients who received a PRBC transfusion following a Norwood operation. The hemoglobin levels (p < 0.01) and the PaO2/FiO2 ratio (p = 0.04) were significantly increased, while arterial lactate levels (p = 0.03) were significantly decreased following the transfusion. Transfusion for a pre-transfusion hemoglobin of 12.4 g/dL appears to provide greatest reduction in lactate, used as a surrogate marker for systemic oxygen delivery. No significant changes were found in arterial pH, PaO2, and PaCO2. PRBC transfusions following the Norwood operation may be a useful intervention to increase systemic oxygen delivery, improving PaO2/FiO2 ratio and improving serum lactate. The benefits of PRBC transfusions must be weighed against previously identified risks on a patient-specific basis. Further studies are warranted to further delineate the effects of such transfusions in this population.

Massive Transfusion in trauma: an evolving paradigm

A considerable amount of literature has nurtured the idea that massive transfusion is an independent trauma disease and therapeutic tool. In this opinion paper, the authors expose the evolution and challenge the classic paradigm and historic definition of massive transfusion. Based on current evidence the elements of an evolving strategy in transfusion management and bleeding control are exposed such as use of tranexamic acid, combination and ratios of blood products, use of fluids and viscoelastic testing. The synergy of these elements provides the basis to develop updated strategies and perspectives for transfusion management after trauma and to consider a classic definition of massive transfusion as outdated or the need for massive transfusion as failure. An alternative concept, Time Critical Transfusion may be better placed to take into account modern transfusion management after trauma.

The Optimal Cell Salvage Settings to Maximize Hematocrit and Minimize Potassium Using the Cobe BRAT2 Autologous Blood Recovery Unit

OBJECTIVE

The objective was to determine the optimal cell saver device settings (infusion rate and wash rate) at which hematocrit is preserved and potassium and lactate are removed from banked red blood cells (RBC).

DESIGN

Red cells were washed using the Cobe BRAT 2 Autologous Blood Recovery Unit and sampled for electrolyte composition and hematocrit pre- and postwash.

SETTING

This was a single-center study.

INTERVENTIONS

Red cells were washed using six infusion rates (100-1,000 mL/min) and six wash rates (100-1,000 mL/min) for a total of 36 combinations. Hematocrit, potassium, glucose, and lactate were evaluated before and after washing.

MEASUREMENTS AND MAIN RESULTS

At wash rates ≤400 mL/min, hematocrit increased independent of infusion rate. At wash rates ≥400 mL/min, slower infusion rates were associated with higher hematocrit compared to faster infusion rates (p < 0.0001 for a wash rate 400-800 mL/min, p < 0.0005 for a wash rate 1,000 mL/min). Maximal wash speeds were associated with decreasing hematocrit. Infusion and wash rate were both independent predictors of potassium change; slower rates were associated with a larger decrease in potassium. Glucose decreased proportionally as infusion and wash rate decreased. Lactate did not show an association with either infusion or wash rate.

CONCLUSION

Red-cell washing produces higher hematocrit and lower potassium as infusion rate and wash rate decrease. A 340-mL unit of RBC can be processed in 4.26 minutes without loss of hematocrit or an increase in potassium when both infusion and wash rates are set to 400 mL/min.

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.

Recent innovations in perfusion and cardiopulmonary bypass for neonatal and infant cardiac surgery

The development and refinement of cardiopulmonary bypass (CPB) has made the repair of complex congenital heart defects possible in neonates and infants. In the past, the primary goal for these procedures was patient survival. Now that substantial survival rates have been achieved for even the most complex of repairs in these patients, focus has been given to the reduction of morbidity. Although a necessity for these complex neonatal and infant heart defect repairs, CPB can also be an important source of perioperative complications. Recent innovations have been developed to mitigate these risks and is the topic of this review. Specifically, we will discuss improvements in minimizing blood transfusions, CPB circuit design, monitoring, perfusion techniques, temperature management, and myocardial protection, and then conclude with a brief discussion of how further systematic improvements can be made in these areas.

The Evolution of Damage Control in Concept and Practice

Damage control surgery (DCS) began as an adjunct approach to hemorrhage control, seeking to facilitate the body's innate clotting ability when direct repair or ligation was impossible, but it has since become a valuable instrument for a broader collection of critically ill surgical patients in whom metabolic dysfunction is the more immediate threat to life than imminent exsanguination. Modern damage control is a strategy that combines the principles of DCS with those of damage control resuscitation. When used correctly, damage control may improve survival in previously unsalvageable patients; when used incorrectly, it can subject patients to imprudent risk and contribute to morbidity. This review discusses the evolution of damage control in both concept and practice, summarizing available literature and experience to guide patient selection, medical decision-making, and strategy implementation throughout the preoperative, intraoperative, and early postoperative periods.

Comparison of stored red blood cell washing techniques for priming extracorporeal circuits

BACKGROUND

The aim of this study was to compare three different blood washing techniques and describe the differences for the composition of the washed red blood cells (RBC).

METHODS

Stored RBCs less than 5 days old were washed using three different techniques. 1) Washing with normal saline with the COBE Model 2991 blood processor in the blood bank (BB-S). 2) Washing with normal saline with the Continuous AutoTransfusion System (C.A.T.S) in the operating room (OR-S). 3) Washing with Plasma-Lyte with the C.A.T.S in the operating room (OR-PL). Then, we compared the values for hemoglobin (Hb), hematocrit (Hct), blood volume, RBC volume, lactate, glucose, sodium and potassium of the three different groups.

RESULTS

Forty-five units of RBCs were washed and analyzed (15 for each technique). The OR-S RBCs, when compared to the BB-S RBCs, had lower hemoglobin (g/dL) (22.8 vs 24.1, p=0.006), lower hematocrit (%) (67 vs 71, p=0.006), higher RBC volume (ml) (161 vs 130, p<0.001), higher glucose (mg/dL) (185 vs 46, p<0.001) and lower sodium (mmol/L) (153 vs 158, p<0.001). When compared to the OR-S RBCs, the OR-PL RBCs showed higher potassium (mmol/L) (5.3 vs 2, p<0.001) and lower sodium (mmol/L) (129 vs 153, p<0.001).

CONCLUSION

RBCs washed with an autotransfusion device had a higher RBC volume and more physiological levels of glucose and sodium when compared with the blood processor in the blood bank. It can be an alternative option to use RBCs washed with an autotransfusion device for priming the extracorporeal circuits utilized in patients undergoing cardiac surgery.

Hemodiafiltration-A Technique for Physiological Correction of Priming Solution in Pediatric Cardiac Surgery: An In Vitro Study

Pediatric cardiopulmonary bypass (CPB) circuit invariably requires priming with packed red blood cells (PRBCs). Metabolic composition of stored PRBCs is unphysiological and becomes worse with increasing duration of storage. It is recommended to correct these abnormalities before initiation of CPB. We tested the hypothesis that hemodiafiltration of the prime with 0.45% saline is sufficient for reducing the metabolic load and reaching a physiologic state. In an in vitro study, 100 mL of blood each from 45 units of PRBCs stored for 3-20 days were used for priming the 45 neonatal CPB circuits. Based upon the method used for removal of excess crystalloid from the prime, circuits were divided into three groups. Group 1: Direct removal through manifold line. Group 2: Ultrafiltration of prime. Group 3: Hemodiafiltration of the prime. Blood gas analyses were obtained from the PRBCs and from the prime before and after removal of crystalloid. Both direct removal of crystalloid and ultrafiltration resulted in significant reduction in biochemical and metabolic load of blood (P < 0.001). However, the final composition of the prime was far from being physiological. Hemodiafiltration resulted in improvement of metabolic parameters to near physiological range (lactate: 33.8 ± 4.44 vs. 14 ± 2.53 mg/dL, pH: 7.05 ± 0.15 vs. 7.34 ± 0.06, bicarbonates: 4.83 ± 0.59 vs. 27.6 ± 2.94 meq/L; P < 0.001). Similarly, sodium (147.76 ± 12.73 vs. 144.6 ± 5.96 meq/L) and potassium (9.6 ± 2.83 vs. 4.23 ± 0.37 meq/L) also changed significantly (P < 0.001) to near physiologic range. Hemodiafiltraion of final prime is a simple, efficients and rapid method of correcting the biochemical parameters and reducing the metabolic load of stored PRBCs towards the physiological range before initiating the CPB.

Comparison of bicarbonate-buffered fluid and isotonic saline solution as Cell Saver washing fluids for packed red blood cells

OBJECTIVES

Massive transfusion (MT) can cause severe electrolyte and acid-base disturbances in neonates and infants due to the unphysiological composition of packed red blood cells (PRBCs). Washing of the PRBCs using Cell Saver systems prior to MT is recommended for this reason.

AIM

The composition of normal saline (NaCl), the standard wash fluid for Cell Saver systems, is considerably different from that of physiological plasma. The aim of the study presented here was to investigate the effect of washing the PRBCs with a bicarbonate-buffered hemofiltration solution (BB-HS) in comparison with washing with NaCl and to evaluate the impact on electrolyte concentrations, acid-base balance and the stability of PRBCs.

METHODS

In an experimental in vitro setting, PRBCs were washed with Cell Saver systems prepared with NaCl or BB-HS as washing solutions. Before and after the washing procedure, electrolyte concentrations, acid-base parameters, adenosine triphosphate (ATP) and free hemoglobin (fHb) concentrations were measured.

RESULTS

In both groups, the potassium concentrations decreased (baseline: 18.4 ± 5.17 mmol·l(-1), end of study: NaCl 2.71 ± 1,81 mmol·l(-1), BB-HS 2.50 ± 1.54 mmol·l(-1), P < 0.05) while the acid-base balance improved only in the BB-HS-group (baseline: base excess -21.6 ± 3.52 mmol·l(-1), end of study: NaCl -30.2 ± 1.42 mmol·l(-1), BB-HS -7.51 ± 2.49 mmol·l(-1) , P < 0.05). Furthermore, markers of erythrocyte stability such as fHb and ATP concentrations were improved in the BB-HS-group.

CONCLUSIONS

Washing of PRBCs with BB-HS rather than NaCl results in a more physiological composition with improvements of electrolyte concentrations, acid-base balance and erythrocyte stability.

Hyponatremia during arginine vasopressin therapy in children following cardiac surgery

OBJECTIVE

To describe the incidence and severity of hyponatremia after initiation of arginine vasopressin therapy in children recovering from cardiothoracic surgery, and to compare these patients with a control group with similar disease complexity and severity who did not receive arginine vasopressin.

DESIGN

Retrospective chart review.

SETTING

PICU at a tertiary care university hospital.

PATIENTS

Twenty-nine patients who received arginine vasopressin for at least 6 hours during the first 48 postoperative hours following cardiothoracic surgery were compared with 47 patients who did not receive arginine vasopressin. After surgery, all patients received intravenous fluids consisting of dextrose and 0.22% saline for daily fluid requirements as well as isotonic colloid and blood products as needed for additional resuscitation.

RESULTS

Mean initial postoperative serum sodium did not differ between groups, 144.6 ± 3.4 in those patients who received arginine vasopressin and 144.5 ± 3.7 in those who did not, p = 0.969. Mean lowest sodium in the first 72 hours, however, was 134.7 ± 3.8 in those who received arginine vasopressin as compared with 137.1 ± 4.3 in the control group, p = 0.019. Hyponatremia occurred in 14 of the patients (48%) who received arginine vasopressin but only in 8 of the patients (17%) in the control group, p = 0.004. Mean age, weight, sex, Aristotle score, and duration of cardiopulmonary bypass were not statistically different between groups. Mean volumes of hypotonic fluids administered and cumulative diuretic dosing during the first 72 hours post-surgery were also not statistically different between groups.

CONCLUSIONS

Hyponatremia occurred in nearly half of the infants and children receiving arginine vasopressin therapy in this study. Clinicians should be aware of this association, monitor serum sodium values closely, and consider providing less free water to these patients before hyponatremia occurs.

Red blood transfusion in preterm infants: changes in glucose, electrolytes and acid base balance

Background:

Preterm neonates comprise the most heavily transfused group of patients, and about 85% of extremely low birth weight newborns receive a transfusion by the end of their hospital stay. The aim of this study was to assess the possible metabolic effects of RBC transfusion on preterm infants, especially during the first 2 weeks of life, and its relation to blood volume.

Materials and Methods:

This study was conducted on 40 preterm neonates with gestational age of less than or equal to 34 weeks. They received RBCs transfusion during first 2 weeks of life. Venous blood samples of infants were collected 2 to 4 hours before and 1 hour after the end of transfusion to evaluate hemoglobin (Hb) level, hematocrit, acid-base, electrolytes, and glucose status. Then, infants were classified into two main groups: those who received RBCs volume less than or 20 ml/kg and those who received RBCs volume more than 20 ml/kg.

Results:

Infants received a mean volume of 20.38 ± 3.2 ml/kg RBCs (range, 10.9 - 26.6 ml/kg) at a median age of 9.8 ± 3.6 days. After transfusion, a significant increase of mean Hb (P<0.001), mean Hct (P<0.001), pH (P<0.001), pO₂ (P<0.05), and a significant decrease of the pCO2 (41.46 ± 8.8torr vs 35.4 ± 9.34 torr; P<0.001) were observed. In addition, there was a significant increase of serum K⁺ (P<0.001), and a significant decrease of Ca⁺² (P<0.001). A positive correlation was found between the K⁺ intake and the changes of kalemia (r = 0.99; P = 0.00). Furthermore, we observed an inverse correlation between the patients’ calcium intake and the changes of calcemia (r = -0.35; P = 0.02). On comparing the changes in clinical and biochemical variables between two groups after transfusion, we observed a significant increase in mean Hb and Hct associated with a significant decrease in mean serum Ca⁺² (P<0.001) in the group receiving the larger blood volume.

Conclusion:

RBC transfusion was effective in improving anemia, oxygenation, increasing pH, and decreasing CO₂ and Ca⁺². However, from a more clinically relevant point of view, we demonstrated the development of hyperkalemia, especially in infants with a previously borderline hyperkalemia.

Washing of banked blood by three different blood salvage devices

BACKGROUND

Storage lesions in red blood cells (RBCs) lead to an accumulation of soluble contaminants that can compromise the patient. Organ failures, coagulopathies, and cardiovascular events including lethal cardiac arrest have been reported, especially with massive transfusion or in pediatric patients. Washing improves the quality of stored RBCs, and autotransfusion devices have been proposed for intraoperative processing, but these devices were designed for diluted wound blood, and limited data on their performance with RBCs are available.

STUDY DESIGN AND METHODS

Three autotransfusion devices (Electa, Sorin; CATS, Fresenius; OrthoPAT, Haemonetics) differing in function of their centrifugation chambers were evaluated with RBCs at the end of their shelf life and with dilutions thereof. Elimination rates of potassium, plasma free hemoglobin, total protein, citrate, acid equivalents, and iomeprol added as a marker substance were analyzed, in addition to RBC recoveries.

RESULTS

Product hematocrit (Hct) levels ranged between 54.8 and 72.6%. RBC recovery rates were between 62.7 and 95.0%, the lowest being with the OrthoPAT processing of undiluted RBCs. Plasma elimination rates increased with predilution and ranged from 46.6% to 99.5%, the lowest being with the CATS and undiluted RBCs. Washing did not change pH and buffering capacity of RBCs.

CONCLUSION

Autotransfusion devices offer a practical and obviously economical option to wash banked RBCs intraoperatively to prevent hyperkalemia and other disturbances in massive transfusion or pediatric patients. Predilution improves elimination rates, especially in devices that produce high product Hct levels. With a Y-tubing the RBCs should bypass reservoir and vacuum, and the procedure should be guarded by a policy and procedure manual and a quality management system.

Impact of a new refrigerator for the preservation of whole blood

BACKGROUND

A new refrigerating system has been recently developed, which can cool the inside of a material to the required temperature by frequently sensing the temperature of both the inside and the surface of the materials. The purpose of this study was to evaluate the usefulness of this new system in whole blood preservation.

MATERIALS AND METHODS

Study 1 (human blood): Whole blood samples from healthy volunteers were anticoagulated with CPDA. The samples were divided into two groups. Group A, whole blood preserved in ordinary refrigerator and Group B, whole blood preserved in new refrigerator (4°C, 15 wk). After preservation, ammonia, lactate, pH. and ATP levels were analyzed. Study 2 (rat experiment): Whole blood samples from male Wistar rats, stored in ordinary refrigerator (Group C) or new refrigerator (Group D). Whole blood was transfused after 8-wk storage and survival was compared.

RESULTS

Study 1: The ammonia concentrations in Group B were significantly lower than those in Group A at 7 and 9 wk after preservation (P < 0.05). The lactate levels in Group B were significantly lower than those in Group A at 9 wk after preservation (P < 005). The pH levels in Group B were higher than those in Group A at 5 to 13 wk after preservation (P < 0.05). The ATP levels in Group B were higher than those in Group A at 5 to 13 wk after preservation. Study 2: In rat studies using blood transfusion in acute hemorrhagic shock model, survival rate in Group C was significantly higher than those in Group D (P < 0.05).

CONCLUSIONS

Our new refrigerator is useful in preserving whole blood with good condition during preservation.

Bicarbonate-buffered ultrafiltration during pediatric cardiac surgery prevents electrolyte and acid-base balance disturbances

Pediatric cardiopulmonary bypass is still a challenge because of electrolyte disturbances and inflammation. Many investigations deal with different types of hemofiltration to reduce these potentially harmful side effects. We tested the hypothesis of whether bicarbonate-buffered hemofiltration of the priming solution minimizes electrolyte and acid-base disturbances during the initiation of cardiopulmonary bypass and whether bicarbonate-buffered hemofiltration performed during cardiopulmonary bypass could reduce cytokine levels. Twenty children younger than 2 years of age (mean age 166 ± 191 days; mean weight 6.42 ± 3.22 kg) scheduled for pediatric cardiac surgery with cardiopulmonary bypass were enrolled in this prospective clinical study. Cardiopulmonary bypass circuits were primed with a bicarbonate-buffered hemofiltration solution, gelatin and 1 unit of packed red blood cells. The priming was hemofiltered using an ultrahemofilter until approximately 1000 mL of ultrafiltrate was restored with the buffered solution. Further hemofiltration was performed throughout the whole bypass time, especially during rewarming. Blood gas analyses and inflammatory mediators were monitored during the operation. Blood gas analysis results after initiation of cardiopulmonary bypass and throughout the entire study remained within the physiologic ranges. Even potassium decreased from 4.0 ± 0.3 to 3.4 ± 0.4 mmol.l−1 after initiation of cardiopulmonary bypass. Plasma levels of tumor necrosis factor alpha decreased significantly (47 ± 44 vs. 24 ± 21 pg.mL−1) whereas complement factor C3a (5.0 ± 2.9 vs. 16.8 ± 6.6 ng.mL−1) and interleukin-6 (7.3 ± 15.2 vs. 110 ± 173 pg.mL−1) increased despite hemofiltration. In conclusion, this study shows that bicarbonate-buffered ultrafiltration is an efficient, simple and safe method for performing hemofiltration, both of the priming solution and during the entire bypass time. The use of a physiological restitution solution prevents electrolyte and acid-base balance disturbances. The elimination of inflammatory mediators seems to be as effective as other ultrafiltration methods.

Bicarbonate buffered ultrafiltration leads to a physiologic priming solution in pediatric cardiac surgery

Pediatric cardiopulmonary bypass (CPB) involves a high ratio of priming blood volume to patient blood volume. The composition of packed red blood cells (RBCs) is very unphysiological in terms of acid-base, electrolyte and metabolite values. Therefore, we tested the hypothesis whether ultrafiltration of the prime and replacement with bicarbonate buffered hemofiltration solution (BB-HS) is sufficient for reducing the metabolic load and reaching a physiologic state. For planned surgery of congenital heart defects with cardiopulmonary bypass, 20 CPB circuits were primed with BB-HS, gelatin and 1 unit of RBCs. The fluid was hemofiltrated using an ultrahemofilter at 300 ml/min until approximately 1000 ml of ultrafiltrate was restored with BB-HS. Blood gas analyses were obtained from the priming blood, once before and once after bicarbonate buffered ultrafiltration (BBUF). The measured substrates decreased significantly (P<0.001) after BBUF (glucose from 13.0+/-2.6 to 6.3+/-1.0 and lactate from 3.8+/-1.5 to 2.3+/-1.0 mmol/l). Acid-base parameters increased (P<0.001) to normal or high normal values (pH from 7.01+/-0.09 to 7.68+/-0.12; HCO(3) from 12.1+/-2.4 to 25.4+/-3.6 mmol/l and BE from -15.4+/-3.6 to -0.8+/-3.7 mmol/l). Even the electrolytes sodium, potassium and calcium changed significantly (P<0.001) toward the physiologic range. BBUF is an efficient method of reducing the metabolic load of priming. After BBUF, even the electrolyte and acid-base balance reached a physiologic state, which is important for minimizing electrolyte and acid-base disturbances after initiation of CPB.

Effects of red blood cell transfusions during the first week of life on acid-base, glucose, and electrolytes in preterm neonates

BACKGROUND

More than 90 percent of extremely low-birth-weight infants receive one or more transfusions of red blood cells (RBCs). The objective was to assess if RBC transfusions may induce significant changes of plasma acid-base, electrolyte, and glucose status in extremely preterm infants.

STUDY DESIGN AND METHODS

Records of infants with gestational age of less than 31 weeks who were transfused with RBCs during the first week of life were reviewed (n = 61). Blood samples were collected from infants before and after transfusions to evaluate hemoglobin (Hb) level, hematocrit, acid-base, electrolyte, and glucose status. Then infants were stratified into four groups that received a RBC volume of less than 15, 15 to 20, more than 20 to 25, or more than 25 mL per kg.

RESULTS

Infants received 20.7 (+/-1.5) mL per kg RBCs. After transfusions, a significant increase of pO(2) (p < 0.0001) and decrease of Ca(2+) (p = 0.047) and glycemia (p < 0.0001) were observed. Infants who were transfused with more than 25 mL per kg were significantly less immature, heavier, and more anemic than infants in other groups. A positive relationship was found between changes of patients' potassium plasma level and K(+) intake through RBC transfusion (r = 0.442, p = 0.008). Three (4.9%) infants developed hyperkalemia, one (1.6%) had an exacerbation of his hypocalcemia, and another (1.6%) of his hypoglycemia.

CONCLUSIONS

RBC transfusions were effective in correcting anemia in our patients and induced a slight increase of pH and pO(2) and decrease of Ca(2+) and glycemia, which were not clinically relevant. A linear direct correlation was observed between potassium intake by RBC transfusions and changes of kalemia in our infants, but there was not an increase of K(+) plasma level after transfusions.

The effect of preprocessing stored red blood cells on neonates undergoing corrective cardiac surgery

This study compared the effect of unprocessed and processed packed red blood cells (PRBCs) with the continuous autotransfusion system (CATS) during neonate heart surgery. Sixteen neonatal patients undergoing cardiac surgery were randomly divided into two groups: unprocessed PRBC (C group, n = 8); processed PRBC (P group, n = 8). The CATS was employed perioperatively. Series laboratory and clinical parameters, including levels of hematocrit, blood potassium, blood glucose, blood lactate, acid-base, and total priming volume of PRBC, were used to compare the effect between the two groups. Before CPB, the hematocrit of processed PRBCs in P group was significantly higher than those in C group (p < 0.01), and the concentrations of potassium, blood glucose, and lactate of processed PRBCs in P group were significantly lower than those in C group (p < 0.01). At the beginning and the end of CPB, the hematocrit levels in P group were all higher than those in C group (p < 0.05); lactate levels in P group were significantly lower than those in C group at the beginning of CPB (p < 0.01), and lower than that of C group at the end of CPB (p < 0.05). The total priming of PRBCs in P group was significantly less than that in C group (p < 0.01). Perioperative processing with CATS provided a high-quality RBC concentration, decreased the total priming of PRBCs, providing increased high-quality blood salvage during neonatal CPB procedure.

Washing of irradiated red blood cells prevents hyperkalaemia during cardiopulmonary bypass in neonates and infants undergoing surgery for complex congenital heart disease

OBJECTIVE

High concentrations of potassium and lactate in irradiated red cells transfused during cardiopulmonary bypass may have detrimental effects on infants and neonates undergoing cardiac surgery. The effects of receiving washed and unwashed irradiated red cells from the cardiopulmonary circuit on serum potassium and lactate concentrations were compared.

METHODS

The study population included neonates and infants undergoing heart surgery for complex congenital heart disease. A control group (n=11) received unwashed irradiated red cells and the study group (n=11) received irradiated red cells washed in a cell saver (Dideco Electa) using 900ml of 0.9% saline prior to pump priming. Potassium and lactate concentrations were compared before, during and after bypass.

RESULTS

Washing irradiated red cells reduced donor blood [potassium] from>20 to 0.8+/-0.1mmol/l, and [lactate] from 13.7+/-0.5 to 5.0+/-0.3mmol/l (p<0.001). The resulting prime had significantly lower [potassium] and [lactate] than the unwashed group (potassium 2.6+/-0.1 vs 8.1+/-0.4mmol/l, p<0.001; lactate 2.6+/-0.2 vs 4.6+/-0.3mmol/l, p<0.001). Peak [potassium] in the unwashed group occurred 3 minutes after going on bypass (4.9+/-0.3mmol/l) and during rewarming (4.9+/-0.4mmol/l). These were significantly higher than the washed group (3.1+/-0.1, p<0.001 and 3.0+/-0.1mmol/l, p<0.001). The [potassium] was greater than 6.0mmol/l for 4 out of these 11 unwashed patients compared with none of the washed group. Immediately post-bypass the washed group had significantly lower serum [potassium] (3.2+/-0.1 vs 4.2+/-0.2mmol/l, p=0.002). There was no significant difference in [lactate] between groups during and after cardiopulmonary bypass.

CONCLUSIONS

The washing of irradiated red cells reduces potassium and lactate loads and prevents hyperkalaemia during cardiopulmonary bypass. The washing of irradiated red cells should be considered in neonates and infants undergoing cardiac surgery for complex congenital heart disease.

The lactate:pyruvate ratio following open cardiac surgery in children

OBJECTIVE

To explore the relationship between lactate:pyruvate ratio, hyperlactataemia, metabolic acidosis, and morbidity.

DESIGN AND SETTING

Prospective observational study in the paediatric intensive care unit (PICU) of a university hospital.

PATIENTS

Ninety-seven children after open cardiac surgery. Most children (94%) fell into low-moderate operative risk categories; observed PICU mortality was 1%.

INTERVENTIONS

Blood was sampled on admission for acid-base analysis, lactate, and pyruvate. Metabolic acidosis was defined as standard bicarbonate lower than 22 mmol/l, raised lactate as higher than 2 mmol/l, and raised lactate:pyruvate ratio as higher than 20.

MEASUREMENTS AND RESULTS

Median cardiopulmonary bypass and aortic cross-clamp times were 80 and 46 min. Metabolic acidosis occurred in 74%, hyperlactataemia in 42%, and raised lactate:pyruvate ratio in 45% of children. In multivariate analysis lactate:pyruvate ratio increased by 6.4 in children receiving epinephrine infusion and by 0.4 per 10 min of aortic cross-clamp. Duration of inotropic support increased by 0.29 days, ventilatory support by 0.27 days, and PICU stay by 0.42 days, for each 1 mmol/l increase in lactate. Neither standard bicarbonate nor lactate:pyruvate ratio were independently associated with prolongation of PICU support.

CONCLUSIONS

Elevated lactate:pyruvate ratio was common in children with mild metabolic acidosis and low PICU mortality. Hyperlactataemia, but not elevated lactate:pyruvate ratio or metabolic acidosis, was associated with prolongation of PICU support. Routine measurement of lactate:pyruvate ratio is not warranted for children in low-moderate operative risk categories.

Unmeasured anions in children after cardiac surgery

OBJECTIVES

Acidosis caused by increased unmeasured anion levels occurs frequently after cardiac surgery, with uncertain significance. We examined the ability of unmeasured anions and lactate to predict major events after cardiac surgery, in addition to lactate/increased unmeasured anion levels during low cardiac output states.

METHODS

In the initial 6 months, all patients admitted after cardiac surgery were enrolled. Arterial samples were taken at 0, 4, 8, 12, 24, and 36 hours postoperatively. The Stewart method was used to calculate excess acid and unmeasured anion levels. Major adverse events were defined as low cardiac output states requiring cardiac massage or mechanical support. In the second 6-month period, data were collected from a further 8 infants during cardiac arrest/extracorporeal membrane oxygenation cannulation.

RESULTS

One hundred thirteen patients were analyzed. Major adverse events occurred in 8 (7.1%) of 113 patients. On admission, metabolic acidosis occurred in 94 of 113 samples: lactate alone (n = 25); mixed lactate and unmeasured anions (n = 44); and unmeasured anions alone (n = 25). All of the patients who experienced major adverse events had unmeasured anion levels of greater than 3 mEq/L on admission. Initial unmeasured anion levels were significantly higher in those infants with major adverse events (10.6 mEq/L [standard deviation, 8.2 mEq/L] vs 4.8 mEq/L [standard deviation, 6.6 mEq/L], P = .024). Lactate levels did not differ between the 2 groups. In the 16 patients sampled during major adverse events, metabolic acidosis occurred in 15 of 16, with a mean excess acid level of 14.9 mEq/L (standard deviation, 8.3 mEq/L). Although unmeasured anions made a significant contribution, lactate was the predominant acid.

CONCLUSIONS

After cardiac surgery, unmeasured anion levels were significantly higher in those children with major adverse events. The greatest risk of major adverse events was found in children with both increased lactate levels and increased unmeasured anion levels on admission.

The strong ion gap predicts mortality in children following cardiopulmonary bypass surgery

OBJECTIVE

Stewart's strong ion theory quantifies unmeasured tissue acids produced following hypoxia or hypoperfusion, by calculation of the strong ion gap. Our study objectives were as follows: a) to determine the 24-hr profile of the strong ion gap following cardiopulmonary bypass surgery; and b) to compare the prognostic value in terms of intensive care unit mortality of this variable with blood lactate.

DESIGN

Prospective, observational study.

SETTING

Tertiary pediatric intensive care unit.

PATIENTS

Eighty-five children following surgery for congenital heart disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Arterial blood samples for lactate and strong ion gap calculation were obtained at intensive care unit admission and at 24 hrs. A raised strong ion gap (>3 mEq/L) was present in 41.1% and 51.7% of admission and 24-hr samples, respectively, being elevated at both time points in 30.5%. Both the strong ion gap and lactate increased with surgical complexity, but neither was correlated with length of bypass (r = .13 and -.02) or aortic cross-clamp (r = .13 and .10). The crude mortality was 5.8% (5/85). Four of the five deaths were associated with a persistently elevated strong ion gap, in contrast to two with ongoing hyperlactatemia (>2 mmol/L). The admission strong ion gap (cutoff, >3.2 mEq/L) was superior to lactate (cutoff, >3.0 mmol/L) as a mortality predictor (area under receiver operating characteristic curve of 0.85 [95% confidence interval, 0.74-0.95] vs. 0.71 [95% confidence interval, 0.44-0.98], respectively).

CONCLUSIONS

An elevated strong ion gap occurs commonly following bypass surgery and appears to be superior to lactate as a mortality predictor.

Systemic Responses to Hemodilution After Transfusion with Stored Blood and with a Hemoglobin-Based Oxygen Carrier

We assessed the systemic effects of exchanges with blood or hemoglobin (Hb) raffimer under conditions of critical oxygen delivery (Do(2)crit). We compared Do(2)crit in animals receiving Hb-based oxygen carrier (HBOC; Hemolink), fresh blood (collected <24 h), or stored blood (10 days) before hemodilution. Rats were randomized to control, blood, or HBOC isovolemic exchange. Oxygen consumption was measured by using expired gas (o(2)a) and blood (o(2)b) samples, whereas whole-body oxygen delivery (Do(2)) was calculated from cardiac output and arterial oxygen content. After exchange, rats were subjected to stepwise isovolemic hemodilution. Blood pressure, gases, acid-base status, glucose, Hb oxygen saturation, heart rate, and total peripheral resistance were also measured. We found that 1) HBOC-treated rats showed an increased mean arterial blood pressure and total peripheral resistance throughout the hemodilution, 2) Do(2)crit calculated with o(2)a or o(2)b gave identical results, 3) Do(2)crit was not different between animals receiving blood and those receiving HBOC, 4) the terminal Hb concentration (1.8 +/- 0.1 g/dL) and Do(2) (5 +/- 1 mL . min(-1) . kg(-1)) were similar for all animals, and 5) most oxygen transport and biochemical variables changed similarly during hemodilution. The data suggest that tolerance to Do(2)crit is not altered by 50% replacement of native Hb by stored blood or Hb raffimer.

The metabolic effects of fresh versus old stored blood in the priming of cardiopulmonary bypass solution for pediatric patients

OBJECTIVES

Pediatric cardiopulmonary bypass involves the creation of a large obligatory priming reservoir. Packed red blood cells are an essential part of the cardiopulmonary bypass priming solution in children. The storage media in packed red blood cells might cause significant acid-base, glucose, and electrolyte imbalances, which have been associated with severe complications. The purpose of the present study was to evaluate the metabolic effects of fresh (< or =5 days) versus old (>5 days) stored packed red blood cells added to the priming solutions of pediatric patients undergoing cardiac surgery.

METHODS

Blood samples were drawn from cardiopulmonary bypass priming of 30 consecutive pediatric patients undergoing cardiac surgery. Patients were divided into 2 groups. Fresh (< or =5 days old) stored packed red blood cells were added to the priming solution in group 1, and old (>5 days old) stored packed red blood cells were added to the priming solution in group 2. In each group blood samples were drawn from the packed red blood cells on arrival to the operating room and from the priming solution immediately after packed red blood cells were added and after 20 minutes of prime circulation. Samples were also collected at the beginning of cardiopulmonary bypass and after 30 minutes. The last sample was collected on arrival to the pediatric intensive care unit. The levels of potassium, glucose, and lactate and the acid-base balance were analyzed in each sample.

RESULTS

There was a linear increase in potassium levels in packed red blood cell samples with increasing packed red blood cell age, ranging from 5.4 to 18.4 mEq/L. Significant differences in the concentrations of potassium, glucose, and lactate and the acid-base balance were found when comparing old and fresh packed red blood cells in samples taken during the packed red blood cell and early prime time. Those differences resolved after 20 minutes of reconstitution of the priming solution. The age of the packed red blood cells had no effect on the samples taken during bypass and those taken in the pediatric intensive care unit.

CONCLUSION

The significantly higher concentration of potassium and lactate and lower pH in old stored packed red blood cells has a minimal effect on the final constitution of priming solution before and during cardiopulmonary bypass in children undergoing corrective cardiac surgery.

Efficacy of a criterion-driven transfusion protocol in patients having pediatric cardiac surgery

OBJECTIVES

Low-hematocrit bypass is one technique used to prevent allogeneic transfusion during cardiopulmonary bypass. The purpose of this study is to determine the efficacy of a criterion-driven transfusion protocol and the effect of low-hematocrit bypass with moderate hypothermia in pediatric cardiac surgery.

METHODS

Seventy-five children who underwent cardiopulmonary bypass with low-hematocrit bypass for repair of congenital heart disease were studied. Criteria for red blood cell transfusion included anemia with a hematocrit level of less than 15% during bypass and 20% after bypass. During cardiopulmonary bypass, venous oxygen saturation, hematocrit values, and regional cerebral oxygenation were continuously monitored. Arterial lactate levels were measured postoperatively.

RESULTS

All patients had an uncomplicated perioperative course, and no perioperative death occurred. Twenty-two patients (29.3%) received a transfusion, and 53 (70.7%) patients did not. The hematocrit levels before and after modified ultrafiltration in the transfused group (21.6 +/- 5.5%, 26.6 +/- 6.5%) were significantly higher than those in the nontransfused group (18.9 +/- 3.7%, 23.1 +/- 4.1%) (P <.05). There was no significant difference between the group's arterial lactate levels immediately after admission to the intensive care unit and 1 day after the operation. The arterial lactate levels 6 hours after the admission to the intensive care unit for the nontransfused patients were higher than with the transfused patients (4.3 +/- 3.0 versus 2.5 +/- 1.5 mmol/L, (P <.05). For arterial lactate level, the relation with patients' weight had the highest correlation (R = 0.678, P <.0001).

CONCLUSIONS

A criterion-driven transfusion program can be effective, and low-hematocrit bypass with a hematocrit value below 20% may affect lactate production or clearance from the body.