Bicarbonate therapy in severely acidotic trauma patients increases mortality

Clinical efficacy of sodium bicarbonate in treating pediatric metabolic acidosis with varying level of acid-base balance parameters: a real-world study

BACKGROUND

Sodium bicarbonate (SB) infusion is commonly used to correct metabolic acidosis, but its clinical efficacy remains controversial. This study aims to investigate whether acid-base balance parameters should be a consideration for administering SB treatment.

METHODS

Children with metabolic acidosis (pH < 7.35 and bicarbonate < 22 mmol/L) who were treated with or without 50 mg/ml SB injection were grouped and extracted from a retrospective cohort database of the Pediatric Intensive Care Unit. The interaction between acid-base balance parameters and SB treatment on mortality was analyzed through mortality curves and cross-effect models. Logistic regression was conducted to estimate the risk of death following SB treatment in the overall children as well as in subgroups, and potential confounding factors were adjusted for. After employing propensity score matching to account for confounding factors, further analysis was performed to evaluate the effectiveness of SB treatment within each chloride subgroup.

RESULTS

A total of 5865 children with metabolic acidosis were enrolled, of which 2462 (42.0%) received SB treatment. In the overall population, it was found that SB treatment did not reduce hospital mortality or 28-day mortality. Interactions between acid-base balance parameters (chloride and anion gap) and SB treatment on mortality were observed. Subgroup analysis clarified that when chloride levels were below 107 mmol/L, children treated with SB had higher in-hospital mortality (29.8% vs 14.9%) and 28-day mortality (26.5% vs 13.4%), with adjusted ORs of 2.065 (95% CI, 1.435-2.97) and 1.947 (95% CI, 1.332-2.846), respectively. In contrast, when chloride levels were greater than or equal to 113 mmol/L, children treated with SB had a shorter stay in the PICU (median: 1.1 days vs 5.1 days, adjusted p = 0.004) and lower in-hospital mortality (4.3% vs 10.3%) and 28-day mortality (4.0% vs 8.4%), with adjusted ORs of 0.515 (95% CI, 0.337-0.788) and 0.614 (95% CI, 0.391-0.965), respectively. After controlling for confounding factors through matching, the impact of SB treatment on the risk of death in each chloride subgroup was consistent with the aforementioned results. However, treatment with SB did not significantly increase the risk of death in newborns or children with moderate to severe metabolic acidosis when chloride levels were below 107 mmol/L (p > 0.05).

CONCLUSIONS

The use of sodium bicarbonate for treating metabolic acidosis has been found to increase mortality in children with low chloride levels but decrease mortality in those with high chloride levels in this study. Further prospective multi-center clinical studies and basic research are needed to validate these findings.

Trauma-induced coagulopathy

Uncontrolled haemorrhage is a major preventable cause of death in patients with traumatic injury. Trauma-induced coagulopathy (TIC) describes abnormal coagulation processes that are attributable to trauma. In the early hours of TIC development, hypocoagulability is typically present, resulting in bleeding, whereas later TIC is characterized by a hypercoagulable state associated with venous thromboembolism and multiple organ failure. Several pathophysiological mechanisms underlie TIC; tissue injury and shock synergistically provoke endothelial, immune system, platelet and clotting activation, which are accentuated by the 'lethal triad' (coagulopathy, hypothermia and acidosis). Traumatic brain injury also has a distinct role in TIC. Haemostatic abnormalities include fibrinogen depletion, inadequate thrombin generation, impaired platelet function and dysregulated fibrinolysis. Laboratory diagnosis is based on coagulation abnormalities detected by conventional or viscoelastic haemostatic assays; however, it does not always match the clinical condition. Management priorities are stopping blood loss and reversing shock by restoring circulating blood volume, to prevent or reduce the risk of worsening TIC. Various blood products can be used in resuscitation; however, there is no international agreement on the optimal composition of transfusion components. Tranexamic acid is used in pre-hospital settings selectively in the USA and more widely in Europe and other locations. Survivors of TIC experience high rates of morbidity, which affects short-term and long-term quality of life and functional outcome.

Acute kidney injury in severely injured patients admitted to the intensive care unit

BACKGROUND

Our objective was to identify possible associations between clinical and laboratory variables and the risk of developing acute kidney injury (AKI) in severely injured patients admitted to the intensive care unit (ICU) for whom creatine kinase (CK) levels were available.

METHODS

For this retrospective observational study, we analyzed adult trauma patients admitted to the ICU from 2011 to 2015 at Fundación Valle del Lili (FVL) University Hospital. Our primary outcome was the incidence of AKI. Multivariate regression analysis was used to assess risk factors for this outcome.

RESULTS

A total of 315 patients were included. The trauma mechanisms were blunt (n = 130), penetrating (n = 66) and blast (n = 44) trauma. The median (interquartile range, IQR) of injury severity score (ISS) was 21 (16-29). AKI developed in 75 patients (23.8%). Multivariate regression analysis revealed that the thoracic abbreviated injury scale (AIS) value (median (IQR) in the AKI group: 3 (0-4)), Acute Physiology and Chronic Health Evaluation (APACHE II) score (median (IQR) in the AKI group: 18 (10-27)), CK greater than 5000 U/L, lactic acid concentration at admission, and dobutamine administration were independently associated with AKI.

CONCLUSION

We found that age, APACHE II score, thoracic trauma, lactic acidosis, and dobutamine administration were independently associated with AKI. Trauma surgeons need to be aware of the increased odds of AKI if one of these factors is identified during the evaluation and treatment of injured patients.

Characterization of Acidosis in Trauma Patient

Background

Recent data suggest that acidosis alone is not a good predictor of mortality in trauma patients. Little data are currently available regarding factors associated with survival in trauma patients presenting with acidosis.

Aims

The aims were to characterize the outcomes of trauma patients presenting with acidosis and to identify modifiable risk factors associated with mortality in these patients.

Settings and Design

This is a retrospective observational study of University of Arkansas for Medical Sciences (UAMS) trauma patients between November 23, 2013, and May 21, 2017.

Methods

Data were collected from the UAMS trauma registry. The primary outcome was hospital mortality. Analyses were performed using t-test and Pearson's Chi-squared test. Simple and multiple logistic regressions were performed to determine crude and adjusted odds ratios.

Results

There were 532 patients identified and 64.7% were acidotic (pH < 7.35) on presentation: 75.9% pH 7.2-7.35; 18.5% pH 7.0-7.2; and 5.6% pH ≤ 7.0. The total hospital mortality was 23.7%. Nonsurvivors were older and more acidotic, with a base deficit >-8, Glasgow Coma Scale (GCS) ≤ 8, systolic blood pressure ≤ 90, International Normalized Ratio (INR) >1.6, and Injury Severity Score (ISS) >15. Mortality was significantly higher with a pH ≤ 7.2 but mortality with a pH 7.2-7.35 was comparable to pH > 7.35. In the adjusted model, pH ≤ 7.0, pH 7.0-7.2, INR > 1.6, GCS ≤ 8, and ISS > 15 were associated with increased mortality. For patients with a pH ≤ 7.2, only INR was associated with increase in mortality.

Conclusions

A pH ≤ 7.2 is associated with increased mortality. For patients in this range, only the presence of coagulopathy is associated with increased mortality. A pH > 7.2 may be an appropriate treatment goal for acidosis. Further work is needed to identify and target potentially modifiable factors in patients with acidosis such as coagulopathy.

Diagnostic et Prise en Charge de l’Acidose Métabolique Recommandations formalisées d’experts communes Société de réanimation de langue française (SRLF) – Société française de médecine d’urgence (SFMU)

L’acidose métabolique est un trouble fréquemment rencontré en médecine d’urgence et en médecine intensive réanimation. La littérature s’étant enrichie de nouvelles données concernant la prise en charge de l’acidose métabolique, la Société de Réanimation de Langue Française (SRLF) et la Société Française de Médecine d’Urgence (SFMU) ont élaboré des recommandations formalisées d’experts selon la méthodologie GRADE. Les champs de la stratégie diagnostique, de l’orientation et de la prise en charge thérapeutique ont été traités et vingt-neuf recommandations ont été formulées : quatre recommandations fortes (Grade 1), dix recommandations faibles (Grade 2) et quinze avis d’experts. Toutes ont obtenu un accord fort. L’application des méthodes d’Henderson-Hasselbalch et de Stewart pour le diagnostic du mécanisme de l’acidose métabolique est discutée et un algorithme diagnostique est proposé. L’utilisation de la cétonémie et des lactatémies veineuse et capillaire est également traitée. L’intérêt du pH, de la lactatémie et de sa cinétique pour l’orientation des patients en pré-hospitalier et aux urgences est envisagé. Enfin, les modalités de l’insulinothérapie au cours de l’acidocétose diabétique, les indications de la perfusion de bicarbonate de sodium et de l’épuration extra-rénale ainsi que les modalités de la ventilation mécanique au cours des acidoses métaboliques sévères sont traitées dans la prise en charge thérapeutique.

Diagnosis and management of metabolic acidosis: guidelines from a French expert panel

Metabolic acidosis is a disorder frequently encountered in emergency medicine and intensive care medicine. As literature has been enriched with new data concerning the management of metabolic acidosis, the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Emergency Medicine Society (Société Française de Médecine d’Urgence [SFMU]) have developed formalized recommendations from experts using the GRADE methodology. The fields of diagnostic strategy, patient assessment, and referral and therapeutic management were addressed and 29 recommendations were made: 4 recommendations were strong (Grade 1), 10 were weak (Grade 2), and 15 were experts’ opinions. A strong agreement from voting participants was obtained for all recommendations. The application of Henderson–Hasselbalch and Stewart methods for the diagnosis of the metabolic acidosis mechanism is discussed and a diagnostic algorithm is proposed. The use of ketosis and venous and capillary lactatemia is also treated. The value of pH, lactatemia, and its kinetics for the referral of patients in pre-hospital and emergency departments is considered. Finally, the modalities of insulin therapy during diabetic ketoacidosis, the indications for sodium bicarbonate infusion and extra-renal purification as well as the modalities of mechanical ventilation during severe metabolic acidosis are addressed in therapeutic management.

Perioperative Management of Lactic Acidosis in End-Stage Liver Disease Patient

Lactic acidosis (LA) in end-stage liver disease (ESLD) patients has been recognized as one of the most complicated clinical problems and is associated with increased morbidity and mortality. Multiple-organ failure, associated with advanced stages of cirrhosis, exacerbates dysfunction of numerous parts of lactate metabolism cycle, which manifests as increased lactate production and impaired clearance, leading to severe LA-induced acidemia. These problems become especially prominent in ESLD patients, that undergo partial hepatectomy and, particularly, liver transplantation. Perioperative management of LA and associated severe acidemia is an inseparable part of anesthesia, post-operative and critical care for this category of patients, presenting a wide variety of challenges. In this review, lactic acidosis applied pathophysiology, clinical implications for ESLD patients, diagnosis, role of intraoperative factors, such as anesthesia and surgery-related, vasoactive agents impact, and also current treatment options and modalities have been discussed.

Effects of an acidic environment on coagulation dynamics

Essentials Acidosis, an outcome of traumatic injury, has been linked to impaired procoagulant efficiency. In vitro model systems were used to assess coagulation dynamics at pH 7.4 and 7.0. Clot formation dynamics are slightly enhanced at pH 7.0 in blood ex vivo. Acidosis induced decreases in antithrombin efficacy offset impairments in procoagulant activity.

SUMMARY

Background Disruption of hydrogen ion homeostasis is a consequence of traumatic injury often associated with clinical coagulopathy. Mechanisms by which acidification of the blood leads to aberrant coagulation require further elucidation. Objective To examine the effects of acidified conditions on coagulation dynamics using in vitro models of increasing complexity. Methods Coagulation dynamics were assessed at pH 7.4 and 7.0 as follows: (i) tissue factor (TF)-initiated coagulation proteome mixtures (±factor [F]XI, ±fibrinogen/FXIII), with reaction progress monitored as thrombin generation or fibrin formation; (ii) enzyme/inhibitor reactions; and (iii) TF-dependent or independent clot dynamics in contact pathway-inhibited blood via viscoelastometry. Results Rate constants for antithrombin inhibition of FXa and thrombin were reduced by ~ 25-30% at pH 7.0. At pH 7.0 (+FXI), TF-initiated thrombin generation showed a 20% increase in maximum thrombin levels and diminished thrombin clearance rates. Viscoelastic analyses showed a 25% increase in clot time and a 25% reduction in maximum clot firmness (MCF). A similar MCF reduction was observed at pH 7.0 when fibrinogen/FXIII were reacted with thrombin. In contrast, in contact pathway-inhibited blood (n = 6) at pH 7.0, MCF values were elevated 6% (95% confidence interval [CI]: 1%-11%) in TF-initiated blood and 15% (95% CI: 1%- 29%) in the absence of TF. Clot times at pH 7.0 decreased 32% (95% CI: 15%-49%) in TF-initiated blood and 51% (95% CI: 35%-68%) in the absence of TF. Conclusions Despite reported decreased procoagulant catalysis at pH 7.0, clot formation dynamics are slightly enhanced in blood ex vivo and suppression of thrombin generation is not observed. A decrease in antithrombin reactivity is one potential mechanism contributing to these outcomes.

Chloride content of solutions used for regional citrate anticoagulation might be responsible for blunting correction of metabolic acidosis during continuous veno-venous hemofiltration

Background

Citrate, the currently preferred anticoagulant for continuous veno-venous hemofiltration (CVVH), may influence acid-base equilibrium.

Methods

The effect of 2 different citrate solutions on acid-base status was assessed according to the Stewart-Figge approach in two consecutive cohorts of critically ill adult patients. The first group received Prismocitrate 10/2 (PC10/2; 10 mmol citrate/L). The next group was treated with Prismocitrate 18/0 (PC18; 18 mmol citrate/L). Both groups received bicarbonate-buffered fluids in post-dilution.

Results

At similar citrate flow, the metabolic acidosis present at baseline in both groups was significantly attenuated in PC18 patients but persisted in PC10/2 patients after 24 h of treatment (median pH 7,42 vs 7,28; p = 0.0001). Acidosis in the PC10/2 group was associated with a decreased strong ion difference and an increased strong ion gap (respectively 43 vs. 51 mmol/L and 17 vs. 12 mmol/L, PC10/2 vs. PC18; both p = 0.001). Chloride flow was higher in PC10/2 than in PC18 subjects (25.9 vs 14.3 mmol/L blood; p < 0.05).

Conclusion

Correction of acidosis was blunted in patients who received 10 mmol citrate/L as regional anticoagulation during CVVH. This could be explained by differences in chloride flow between the applied citrate solutions inducing hyperchloremic acidosis.

Hemodynamic consequences of severe lactic acidosis in shock states: from bench to bedside

Lactic acidosis is a very common biological issue for shock patients. Experimental data clearly demonstrate that metabolic acidosis, including lactic acidosis, participates in the reduction of cardiac contractility and in the vascular hyporesponsiveness to vasopressors through various mechanisms. However, the contributions of each mechanism responsible for these deleterious effects have not been fully determined and their respective consequences on organ failure are still poorly defined, particularly in humans. Despite some convincing experimental data, no clinical trial has established the level at which pH becomes deleterious for hemodynamics. Consequently, the essential treatment for lactic acidosis in shock patients is to correct the cause. It is unknown, however, whether symptomatic pH correction is beneficial in shock patients. The latest Surviving Sepsis Campaign guidelines recommend against the use of buffer therapy with pH ≥7.15 and issue no recommendation for pH levels <7.15. Furthermore, based on strong experimental and clinical evidence, sodium bicarbonate infusion alone is not recommended for restoring pH. Indeed, bicarbonate induces carbon dioxide generation and hypocalcemia, both cardiovascular depressant factors. This review addresses the principal hemodynamic consequences of shock-associated lactic acidosis. Despite the lack of formal evidence, this review also highlights the various adapted supportive therapy options that could be putatively added to causal treatment in attempting to reverse the hemodynamic consequences of shock-associated lactic acidosis.

Sodium bicarbonate therapy in patients with metabolic acidosis

Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated.

Efficient Extra- and Intracellular Alkalinization Improves Cardiovascular Functions in Severe Lactic Acidosis Induced by Hemorrhagic Shock

Background:

Lactic acidosis is associated with cardiovascular failure. Buffering with sodium bicarbonate is proposed in severe lactic acidosis. Bicarbonate induces carbon dioxide generation and hypocalcemia, both cardiovascular depressant factors. The authors thus investigated the cardiovascular and metabolic effects of an adapted sodium bicarbonate therapy, including prevention of carbon dioxide increase with hyperventilation and ionized calcium decrease with calcium administration.

Methods:

Lactic acidosis was induced by hemorrhagic shock. Twenty animals were randomized into five groups: (1) standard resuscitation with blood retransfusion and norepinephrine (2) adapted sodium bicarbonate therapy (3) nonadapted sodium bicarbonate therapy (4) standard resuscitation plus calcium administration (5) hyperventilation. Evaluation was focused in vivo on extracellular pH, on intracellular pH estimated by P31 nuclear magnetic resonance and on myocardial contractility by conductance catheter. Aortic rings and mesenteric arteries were isolated and mounted in a myograph, after which arterial contractility was measured.

Results:

All animals in the hyperventilation group died prematurely and were not included in the statistical analysis. When compared with sham rats, shock induced extracellular (median, 7.13; interquartile range, [0.10] vs. 7.30 [0.01]; P = 0.0007) and intracellular acidosis (7.26 [0.18] vs. 7.05 [0.13]; P = 0.0001), hyperlactatemia (7.30 [0.01] vs. 7.13 [0.10]; P = 0.0008), depressed myocardial elastance (2.87 [1.31] vs. 0.5 [0.53] mmHg/μl; P = 0.0001), and vascular hyporesponsiveness to vasoconstrictors. Compared with nonadapted therapy, adapted bicarbonate therapy normalized extracellular pH (7.03 [0.12] vs. 7.36 [0.04]; P &lt; 0.05), increased intracellular pH to supraphysiological values, improved myocardial elastance (1.68 [0.41] vs. 0.72 [0.44] mmHg/μl; P &lt; 0.05), and improved aortic and mesenteric vasoreactivity.

Conclusions:

A therapeutic strategy based on alkalinization with sodium bicarbonate along with hyperventilation and calcium administration increases pH and improves cardiovascular function.